Ye Olde Rocket Forum - Designer's Corner

CPMcGraw

01-09-2007, 12:55 AM

In keeping with the nature of this private development forum, I am starting this thread for posts dealing exclusively with new model rocket designs that will use some of the new motors we are anticipating from SEMROC. It should be understood that designs presented here cannot be openly discussed on the "public" side of Ye Olde Rocket Forum, as they will contain information which has not been made available to the general public. Therefore, anything presented here will NOT be posted to the BARCLONE website until after such information has been released by SEMROC, nor will it be transferred to the "Scrounged" thread for general release.

I am going to set some additional rules for this thread. While most of the designs on the public "Scrounged" thread presently follow these rules, on this thread they will have to. First: All plans must be submitted in RockSim file format. Second: Include the 2D and 3D exported images from RockSim as visual references. Third: When rendering the 3D image, set the resolution to HIGH, and fill the window with the image; we need the largest 3D image RockSim can produce. Fourth: Send the 3D image as a JPG file, not as a PNG or BMP.

As information comes in on the new motors, special motor files and component CSV files will be created and posted on this thread for exclusive advanced use by the SVDT designers. These files are not to be shared, or made publicly available. These files will also be subject to unannounced change as circumstances warrant.

CPMcGraw

01-09-2007, 01:46 PM

The following motor file was developed for testing by adapting the Apogee motors from 1/4A through B. Both 10mm and 15mm sizes have been simulated where possible. The motor power/delay curves have not been modified, but the time delay values have been added to cover a number of choices, generally beginning with 2 or 3 seconds, and going as high as 9 seconds. Some of these values will be arbitrarily high, but it allows for simulation tweaking.

Remember: These motors are for testing only, and do not necessarily represent the final production motors. It's just a starting point.

How to use:

Unzip the SEMROC.ZIP to get the SEMROC.RSE file. Save the RSE file in your DATA folder in the RockSim directory. Open RockSim. Click FILE | Reload Engines. Add the SEMROC.RSE file to the list on the right. Close this window. You can now use the SEMROC motors in your designs.

CPMcGraw

01-09-2007, 01:56 PM

Here is the first BARCLONE design to use a 10mm 1/4A2-4 SEMROC motor. It is a micro version of an early MMI favorite, the Aerobee 150. This one is called the Microbee 150. It is streamer-recovery, and has spectacular performance.

Length: 9.06"
Diameter: 0.448" (Apogee 10.5mm tubes)
Fin Span: 2.188"
Weight: 0.1173 oz

1/4A2-4T......370'......Dv 6 FPS......18" launch rod

Notice the last column -- it takes only an 18" launch rod to reach safe flight velocity.

Also note, I tried to create a new ST-4 body tube for use with these motors, but RockSim declared the diameters to be only usable with 6mm MicroMaxx motors. It would not offer the 10mm motors as an option. This will be tweaked later in the program.

Study the new design and get the feel for what's in the works!

Pyro Pro

01-09-2007, 03:00 PM

Here's one I designed a few months ago. It's not designed specifically for any of the new motors (although the design could very easily be adapted), but I thought it would make a neat kit.

The Micro Hustler, a 42.65% scale model of the SLS Hustler. Uses 18mm motors, but could also be adapted to fly on 13mm or 10mm motors. Gets to about 1450' with a C6.

Length: 16.3015"
Diameter: 0.998", 0.759" (ST-9 payload section, ST-7 body)
Fin Span: 4.8751"
Weight: 0.7675 oz

1/2A6-2 . . . . . . 130' . . . . . . Dv 20 FPS* . . . . . . 36" launch rod
C6-7 . . . . . . . . 1448' . . . . . . Dv 26.6 FPS* . . . . 36" launch rod

*Both simulations are "in between" delays, a 1/2A6-3 or a C6-6 would be nice :rolleyes:

CPMcGraw

01-09-2007, 03:39 PM

Pyro,

I modified your design (nice one, BTW...) to use the 10mm motors, with a motor mount based on 10.5mm tubes. Not too shabby results...

Hope you like how this turned out...

ADDENDUM: And no sooner than I get this posted, I discover it needs a long rod (49" long!) to become stable on this motor.

Let me try this one again on 15mm power...

CPMcGraw

01-09-2007, 03:51 PM

OK, sorry about the weak design with the 10mm motor. It almost worked. The truth is, I ran into the same issue with the A2 motor I've included here. It's a weak motor for this size model.

The B2 and B7 motors are better; the B7 is perhaps the best of the three, jumping off the pad with enough velocity to get stable in 18". The B2 requires a full 36" of launch rod, so it's right at the transition.

CPMcGraw

01-09-2007, 04:06 PM

OK, I've added some old favorites to the SEMROC.RSE file. I've cobbled the Estes 1/4A through B6 motors into 10mm and 15mm packages, and I've added these with the previous batch.

If you've already added the previous file, just replace that file with this one. If you haven't installed that first version yet, unzip this file to the DATA folder for RockSim, open RockSim, and click FILE | Reload Engines. Add this file from the left column to the right column, close that window, and you're set to go.

CPMcGraw

01-09-2007, 04:36 PM

This is Version 3. Some corrections have been made to the list. These represent only the 10mm and 15mm 1/4A through B motors.

Pyro Pro

01-09-2007, 05:15 PM

Thanks,

Well, after posting my Micro Hustler, I decided that I wanted to design something impressive to go with the 10mm motors. The first rocket that came to mind was the Saturn V, so after about 2 hours of designing (4:00 -> 5:50), it was finished. The resulting model is based on the ST-16 body tube, and flies on a cluster of FIVE 10mm motors. Since I couldn't accurately represent the shrouds around the base of the body in RockSim, I substituted ST-7 and ST-4 sized tube (but if this were to be built they would be paper or balsa parts). Other than that, it's as accurate as I could make it (including an escape tower :D).

The 10mm Saturn V
Scale: 1/245.5

Length: 17.3225"
Diameter: 1.64"
Fin Span: 3.08"
Weight: 2.7451 oz (with noseweight)

(5x) 1/2A2-5 . . . . . . 470' . . . . . . . Dv 7.21 FPS . . . . . . 36" launch rod

*On the actual model, the S-II, S-IVB, SM and CM would come down horizontally on one parachute, and the S-IC first stage would come down on it's own parachute as well, which should help the descent rate and prevent damage to the upper stages.

Well, here it is:

Pyro Pro

01-09-2007, 05:37 PM

CPMcGraw

01-09-2007, 05:58 PM

Well, I was just reading over the motor thread, and saw a mention of ST-6 body tube for 15mm motors, with an OD of 0.62". That would be a more "to scale" size for the command module body (actual size is somwhere arount .65"), and could replace the current ST-5 tube.

The ST-6 is my own creation -- it doesn't actually exist yet. I needed a tube to use as a motor tube for the 15mm, so I created those specs to "fit" the motor casing with similar play to the ST-5 using the 13mm motors.

OD = 0.620"
ID = 0.594"
Wall Thickness = 0.013" (Same as ST-5)

CPMcGraw

01-09-2007, 07:07 PM

Here's an example of what we could be doing in the area of two-stage models once we get the booster motors. This design is tweaked for 10mm motors.

Length: 23.45"
Diameter: 0.908" (ST-8)
Fin Span: 4.41"
Weight: 1.105 oz

A8-0 | 1/2A6-5......430'......Dv 25 FPS
A10-0 | A8-5........700'......Dv 2 FPS
A8-0 | A10-5........724'......Dv 12 FPS
A10-0 | A10-4.......750'......Dv 22 FPS
A8-0 | A3-5.........755'......Dv 5 FPS
A10-0 | A3-5........780'......Dv 5 FPS

The model qualifies as a "Schoolyard Sounder" by using motors 13mm or smaller [I may allow 15mm motors here, but not just yet.] All motor combinations reach flight velocity on a 36" standard rod.

Enjoy!

CPMcGraw

01-09-2007, 07:29 PM

In the spirit of the Farside-X, here is the Whippit-X.

Length: 22.5"
Diameter: 1.04" (ST-10)
Fin Span: 4.41"
Weight: 1.16 oz

A8-0 | 1/2A6-4......410'......Dv 7 FPS
A10-0 | A8-5........668'......Dv 5 FPS
A8-0 | A10-5........700'......Dv 14 FPS
A8-0 | A3-5.........725'......Dv 9 FPS
A10-0 | A10-5.......726'......Dv 13 FPS
A10-0 | A3-5........750'......Dv 8 FPS

All motor combinations reach flight velocity on a standard launch rod.

Enjoy!

CPMcGraw

01-09-2007, 07:44 PM

Better results using the most-recent motor file...

Length: 16.3"
Diameter: 0.998" (ST-9)
Fin Span: 4.875"
Weight: 0.83 oz

1/2A6-3......121'......Dv 15 FPS
A8-4......358'......Dv 3 FPS
A10-4......413'......Dv 4 FPS
A3-4......421'......Dv <1 FPS

Thanks for the great design, David. This is going to be a popular model when those motors finally come on-line. I like this one!

CPMcGraw

01-09-2007, 08:11 PM

Version 4. I added the Quest A6 and B6 sizes to the 10mm and 15mm lines.

Same installation instructions as before.

rocket_james

01-09-2007, 08:19 PM

How to use:

Unzip the SEMROC.ZIP to get the SEMROC.RSE file. Save the RSE file in your DATA folder in the RockSim directory. Open RockSim. Click FILE | Reload Engines. Add the SEMROC.RSE file to the list on the right. Close this window. You can now use the SEMROC motors in your designs.
All of my engine files are accessed as .eng files. Am I missing something?
James

CPMcGraw

01-09-2007, 08:35 PM

All of my engine files are accessed as .eng files. Am I missing something?
James

What you have are RASP files. If you are using RockSim versions 7 or 8, you can import ENG files into the EngEdit program and convert them to RSE (RockSim Engine) files. RockSim reads RSE files only, but the Engine Editor program is where you create new engine values, or (as I'm doing) modify existing data files to appear as the new motors.

rocket_james

01-09-2007, 09:01 PM

What you have are RASP files. If you are using RockSim versions 7 or 8, you can import ENG files into the EngEdit program and convert them to RSE (RockSim Engine) files. RockSim reads RSE files only, but the Engine Editor program is where you create new engine values, or (as I'm doing) modify existing data files to appear as the new motors.
Interesting, as there are no .rse files in my Data folder except the Semroc files you provided. I am using RockSim version 7. I do have an RSEngine.dbs file, though. Nothing happens when I open RockSim and select File>Reload engine data.
James

CPMcGraw

01-09-2007, 09:25 PM

Interesting, as there are no .rse files in my Data folder except the Semroc files you provided. I am using RockSim version 7. I do have an RSEngine.dbs file, though. Nothing happens when I open RockSim and select File>Reload engine data.
James

Interesting. Apogee must have made a change between 7 and 8. I use version 8, and just had it updated in the last week. Let me look into this, and I'll see what can be done.

CPMcGraw

01-09-2007, 09:36 PM

Another cluster of 10mm motors. This design is a 5-fin sibling to the Snitch.

Length: 22.8"
Diameter: 1.04" (ST-10)
Fin Span: 4.04"
Weight: 1.26 oz

(3) 1/2A3-4......365'......Dv 5 FPS
(3) A6-5.........602'......Dv 11 FPS
(3) A8-5.........667'......Dv 13 FPS
(3) A10-5........795'......Dv 3 FPS
(3) A3-5.........819'......Dv 15 FPS

Enjoy!

rocket_james

01-09-2007, 09:36 PM

Thanks, Craig. I really don't remember, but my original version may have been V5 on disk, then upgraded to V7 by download. At least the pdf manual that is in my files appears to be from V5, RS5MANV2. At any rate, my engine compiler, COMPENG, only looks for the RASP or .eng files.
James

CPMcGraw

01-09-2007, 10:05 PM

Thanks, Craig. I really don't remember, but my original version may have been V5 on disk, then upgraded to V7 by download...
James

Try the latest DEMO from Apogee to use these files. It's good for 30 days (I think). I'm really waiting to see what version 9 might have in it, if and when it finally comes out.

CPMcGraw

01-09-2007, 10:19 PM

Folks, I had to create some new tube sizes to use the 10mm and 15mm motors, so keep in mind you can't just order up these tubes yet from SEMROC to build anything. These new tubes -- called ST-4 and ST-6 -- will need to be manufactured and sold to Carl first.

Another reminder -- Carl may not select these sizes for the final parts. He may have something else in mind. But for now, these are the dimensions I am using.

ST-4 dimensions: 0.399" ID, 0.425" OD Wall thickness 0.013"
ST-6 dimensions: 0.594" ID, 0.620" OD Wall thickness 0.013" [thin wall]
ST-6 dimensions: 0.594" ID, 0.636" OD Wall thickness 0.021 [thick wall]

Hope this will help everyone with their new designs.

CPMcGraw

01-10-2007, 12:34 AM

A little more ambitious project here...

A sibling to the (still untested) Andromeda, but using only a two-cluster 10mm mount.

Length: 29.2"
Diameter: 1.04" (ST-10)
Fin Span: 8.08"
Weight: 1.84 oz

(2) A8-4.......315'......Dv 10 FPS
(2) A10-4......355'......Dv 13 FPS
(2) A3-4.......365'......Dv 9 FPS

All motors reach flight velocity on a standard rod.

Enjoy!

CPMcGraw

01-10-2007, 01:52 PM

Based on the Centuri Long Tom, this two-stage model fills my requirement for a "Schoolyard Sounder" nicely. Everything happens within visual range, too. All motors reach flight velocity in the length of a standard rod, though admittedly at the very tip of the rod...

Length: 24.0"
Diameter: 1.04" (ST-10)
Fin Span: 5.04"
Weight: 1.16 oz

1/2A6-0 | 1/2A3-4......280'......Dv 17 FPS
A6-0 | 1/2A6-4.........355'......Dv 5 FPS
A8-0 | 1/2A6-4.........375'......Dv 5 FPS
A10-0 | A3-4...........655'......Dv 10 FPS

Enjoy!

CPMcGraw

01-10-2007, 05:56 PM

Now includes the B14 curve in 15mm.

CPMcGraw

01-10-2007, 07:44 PM

This model tries to use a wide variety of power cores to get the optimum results. It may be a 3FNC, but the performance is great, and the semi-open-frame fins give it a bit more personality.

Length: 17.463"
Diameter: 0.908" (ST-8)
Fin Span: 5.91"
Weight: 0.84 oz

1/2A6-3......122'......Dv 15 FPS
A6-4.........323'......Dv 2 FPS
A8-4.........363'......Dv 1 FPS
A10-4........422'......Dv 2 FPS
A3-4.........428'......Dv 6 FPS
B14-6........786'......Dv 5 FPS
B6-6.........787'......Dv 15 FPS
B8-6.........806'......Dv 8 FPS
B7-6........1012'......Dv 6 FPS
B2-5........1021'......Dv 10 FPS

All motors reach flight velocity on a standard launch rod.

Enjoy!

snaquin

01-10-2007, 10:05 PM

Let me start by saying the Semroc Lune R-1 Retro-Repro is a really cool little rocket :)

I wanted to design a "new" two stager and wanted a sleek light weight sustainer that looked good but would fly well on some of the estimated engine simulation files that Craig created.

I just couldn't get past the good looks of the Lune R-1 so I built a booster for it. The nice thing about this design is you just toss an extra set of fins in the bag with an extra motor mount and a short 3" piece of ST-10 and it's ready to ship. The Lune R-1 sustainer is already set up to carry a payload.

I simmed it with larger Estes D and E motors and the design would lend itself well to a slight upscale to SLS proportions using LT-125 for the airframes (although there are no LT-125 or ST-13 conical nose cones listed at this time).

Minimum velocity for stable flight reached at just under 17 inches with the B14-0 booster motor Craig provided.

Length: 26.3"
Diameter: 1.04" (ST-10)
Fin Span: 4.04"
Weight: 1.75 oz

B8-0 | B7-6......1,073'......Dv 7 FPS
B14-0 | B2-5........1,143'......Dv 2 FPS
C6-0 | C6-7........1,816'......Dv 23 FPS

.

Carl@Semroc

01-10-2007, 10:27 PM

Thanks, Steve!

I never thought of the Lune R-1 as a two-stage; that looks really neat.

SEL

01-11-2007, 02:28 PM

Let me start by saying the Semroc Lune R-1 Retro-Repro is a really cool little rocket :) ........

Coincidently enough I just ordered one, along with a few others I've been meaning get, last night. I had surgery on my right knee yesterday and figured I'll have some time over the next few weeks to put together some easier kits in between Saturn 1B work sessions.
Anyway, to get back on topic, I've taken to leaving room for boosters on the last few clones that I've built (FSI NOVA, Voyager, EOS to name a few) and like Steve thought the Lune R-1 would be a fine candidate as well. As far as an SLS upscale, doesn't Carl make a FSI Black Brant cone?

Sean

rocket_james

01-11-2007, 07:22 PM

As far as an SLS upscale, doesn't Carl make a FSI Black Brant cone?

Sean
Isn't it the BC-20107? It is the equivalent of the FSI NC-191 per the conversion list on Carl's site.

SEL

01-11-2007, 08:35 PM

Isn't it the BC-20107? It is the equivalent of the FSI NC-191 per the conversion list on Carl's site.

Thanks, that's the one - I was just too lazy to look it up.

S.

snaquin

01-11-2007, 09:22 PM

Thanks, Steve!

I never thought of the Lune R-1 as a two-stage; that looks really neat.

Carl,

Thanks for the compliment; I do appreciate that! I thought about adding a paper shroud to the sustainer aft end like the original version Lune R-1 but I wasn't sure of the dimensions. The Lune R-1 and booster parts are on my list of Semroc items I intend to get with my next order :)

Coincidently enough I just ordered one, along with a few others I've been meaning get, last night. I had surgery on my right knee yesterday and figured I'll have some time over the next few weeks to put together some easier kits in between Saturn 1B work sessions.
Anyway, to get back on topic, I've taken to leaving room for boosters on the last few clones that I've built (FSI NOVA, Voyager, EOS to name a few) and like Steve thought the Lune R-1 would be a fine candidate as well. As far as an SLS upscale, doesn't Carl make a FSI Black Brant cone?

Sean

Sean,

I hope you are feeling better today and recovery from the surgery you had is a complete success. I'm going to pick your brain soon about your FSI clones. The Voyager, OSO and Mach-1 Dart were my favorite F engine rockets. I'll have to check the Semroc site to see what sizes the conical shaped cones are available in, I only looked for ST-13 and LT-125 sizes. I was working on some Mach-1 Dart simulations with Semroc parts last night and here is what I came up with.

*** Semroc Mach 1 Dart with Thruster System ***

"FSI presents the mach 1 system - A model rocket system with the ability to BREAK THE SOUND BARRIER". As a teenager when I first read those words in the FSI catalog I rushed to buy one. I had to have it. Most are familiar with the original design with the fins glued directly to the F100-0 booster and all the versions I had the D20 for the sustainer slipped directly into the top of the F100 and it looked as if perhaps a couple of cardboard layers of the id of the F100 were removed to accomplish this slip fit. I'm not sure, because I don't remember but I don't think a standard FSI D20 would slip fit in the top of an F100. I thought I read somewhere that some users had a coupler for the stages but all of the ones I built the sustainer motor slipped directly into the top of the F100.

Since the 24mm and 29mm Semroc PB port burners will be last in the production schedule, I can't guess if this type of coupling the booster and sustainer could be duplicated. Instead of having fins glue directly to a 29mm motor I used a LT-125 tube for the booster with a small sleeve to allow the 24mm sustainer motor to slip through to couple the stages. I'm not real fond of this configuration because it shifts the CG back by moving the booster motor aft one inch and would probably require about 1/2oz of nose weight. This may not be necessary when we have the Semroc 29mm port burners in hand, so consider this "a work in progress".

I'm sure the Semroc PB's will have no problem with achieving the needed velocity in a two stage rocket and I'm convinced the reason the FSI version was so efficient was due to a good design and PB motors. The F100 was barely an F at only 41.6 ns and the D20 was 17 ns. It could quite possibly be done with Semroc PB's staged E to D depending on the final designs.

Since both stages of the Semroc design use airframes, this could easily be adapted for 15mm and 18mm Semroc PB's for a smaller field and you don't waste gluing the booster fins to a disposable motor, making the booster reusable.

Although not a new idea, this would be a model rocket system design that would only be able to be achieved using Semroc PB engines. None of the other rocket companies could make this claim.

It could be a fun design challenge for Semroc Virtual Design Team to improve on the original design. Creativity is certainly not lacking with the members of SVDT! Possibly make something uniquely Semroc. I toyed with the Lune R-1 as a sustainer with only 3 fins and with a redesigned booster. Any other ideas?

What do you guys think?

.

rocket_james

01-11-2007, 11:08 PM

I was working on some Mach-1 Dart simulations with Semroc parts last night and here is what I came up with.

*** Semroc Mach 1 Dart with Thruster System ***

What do you guys think?

.
Cool! I like the idea. Machs my day! :D
James

SEL

01-12-2007, 02:44 AM

Sean,

I hope you are feeling better today and recovery from the surgery you had is a complete success. I'm going to pick your brain soon about your FSI clones. The Voyager, OSO and Mach-1 Dart were my favorite F engine rockets.

Ouch! Just go easy there, Stevie-boy - there's mighty slim pickins up there at this point :eek:

Sean

barone

01-12-2007, 08:52 PM

.... I'm going to pick your brain soon about your FSI clones. The Voyager, OSO and Mach-1 Dart were my favorite F engine rockets. I'll have to check the Semroc site to see what sizes the conical shaped cones are available in, I only looked for ST-13 and LT-125 sizes. I was working on some Mach-1 Dart simulations with Semroc parts last night and here is what I came up with.

What do you guys think?

Steve,

I like the idea. I only got to fly my Dart once (I thought it blew up when it hit mach....you know those pesky, prone to cato, FSI motors). And, as you've mentioned, the current assortment of motors just can't make it work now. Another interesting configuration would be for the FSI Intrepid. It used a cluster of one F100-6 and two D20-0s. I'd sure like to fly it the way it was intended.......

snaquin

01-12-2007, 10:31 PM

Steve,

I like the idea. I only got to fly my Dart once (I thought it blew up when it hit mach....you know those pesky, prone to cato, FSI motors). And, as you've mentioned, the current assortment of motors just can't make it work now. Another interesting configuration would be for the FSI Intrepid. It used a cluster of one F100-6 and two D20-0s. I'd sure like to fly it the way it was intended.......

Hey Don,

I remember the picture you posted a while back of your Mach 1 Dart. IIRC you had a white dart and booster on top of a tall tripod.

I never owned the FSI Intreped but I remember when I came out. I waited too long and FSI went out of business before I hand a chance to get one. :mad:

It goes without saying that Semroc port burners will change the way we fly rockets. It opens up a lot of welcomed new possibilities. I would imagine the longer burn EB motors will set new contest records.

.

barone

01-13-2007, 02:05 AM

I remember the picture you posted a while back of your Mach 1 Dart. IIRC you had a white dart and booster on top of a tall tripod. Yep, I remember that somewhere. That tripod sure makes it easy to hook up igniter wires......

I never owned the FSI Intreped but I remember when I came out. I waited too long and FSI went out of business before I hand a chance to get one. :mad:

You know, you can almost clone it. Instructions and templates are here http://www.oldrocketplans.com/fsi/fsi1032/fsi1032.htm and Carl has a partial partslist here http://www.semroc.com/Store/scripts/ClassicParts.asp?ID=695 (well, two items with add buttons) :rolleyes:

Ltvscout

01-13-2007, 09:23 AM

You know, you can almost clone it. Instructions and templates are here http://www.oldrocketplans.com/fsi/fsi1032/fsi1032.htm and Carl has a partial partslist here http://www.semroc.com/Store/scripts/ClassicParts.asp?ID=695 (well, two items with add buttons) :rolleyes:
When looking for parts to clone old kits, always ask Carl if he has the other parts available that aren't listed. He has many parts for kits that haven't been posted to his site yet.

Initiator001

01-13-2007, 12:25 PM

FWIW,

Years ago, I flew a FSI Dart system at the (only) night 'velocity' launch outside of Las Vegas.

The D20 didn't ignite (my mistake) but the F100 booster pushed the model to 460 MPH.

Bob

CPMcGraw

01-13-2007, 08:28 PM

Latest file includes the C10 and B14 in the 18mm packages. Added the 13mm and 18mm packages for several of the other motors as well.

CPMcGraw

01-13-2007, 09:05 PM

This is a revision of an older design, but one that really begs for one of the potential SEMROC motors. I tried out a C10-3, and wound up with the perfect match. The Dv is feather-soft at a mere 3 FPS, and the time delay of 3 seconds was just ahead of apogee. The model jumps off the pad and reaches flight velocity in less than 20".

Length: 40.196"
Diameter: 1.34" (ST-13)
Fin Span: 8.11"
Weight: 3.41 oz

C10-3......360'......Dv 3 FPS

I chose to use the 3/16" launch rod due to the length of the model.

Enjoy!

James Pierson

01-15-2007, 07:22 PM

Craig said,

Folks, I had to create some new tube sizes to use the 10mm and 15mm motors, so keep in mind you can't just order up these tubes yet from SEMROC to build anything. These new tubes -- called ST-4 and ST-6 -- will need to be manufactured and sold to Carl first.

Another reminder -- Carl may not select these sizes for the final parts. He may have something else in mind. But for now, these are the dimensions I am using.

ST-4 dimensions: 0.399" ID, 0.425" OD Wall thickness 0.013"
ST-6 dimensions: 0.594" ID, 0.620" OD Wall thickness 0.013" [thin wall]
ST-6 dimensions: 0.594" ID, 0.636" OD Wall thickness 0.021 [thick wall]

Craig, I realize that these new tubes are preliminary but I just
started thinking like a carpenter again :o .
I was just playing with these ST-4 and ST-6 tube as motor mounts and
realize that they don't fit very well into other tubes(ST-5 and ST-7).
Maybe we should make them a little thicker to fit into other tubes as
sleeve motor mounts.

*Maybe ST-4 OD(.425) change to .51 to fit into a ST-5(.515)
*Maybe ST-6 OD(.626) change to .745 to fit into a ST-7(.715)
I am narrowing each about .005 which is what Carl's HTC couplers are narrowed.

My reason are to easily fit the new tubes into existing tubes. Also I
like the ST-5 tubes from the SchoolYard Sounder design and would like
to use the 10mm motors in them easily. Also there are no nose cones for either
new tube and an CR that is .09 tall is just too small (ST-4 to ST-5) :( .

What are your thoughts on this.

James Pierson
NAR# 77907

foose4string

01-15-2007, 08:50 PM

Craig said,

Craig, I realize that these new tubes are preliminary but I just
started thinking like a carpenter again :o .
I was just playing with these ST-4 and ST-6 tube as motor mounts and
realize that they don't fit very well into other tubes(ST-5 and ST-7).
Maybe we should make them a little thicker to fit into other tubes as
sleeve motor mounts.

*Maybe ST-4 OD(.425) change to .51 to fit into a ST-5(.515)
*Maybe ST-6 OD(.626) change to .745 to fit into a ST-7(.715)
I am narrowing each about .005 which is what Carl's HTC couplers are narrowed.

My reason are to easily fit the new tubes into existing tubes. Also I
like the ST-5 tubes from the SchoolYard Sounder design and would like
to use the 10mm motors in them easily. Also there are no nose cones for either
new tube and an CR that is .09 tall is just too small (ST-4 to ST-5) :( .

What are your thoughts on this.

James Pierson
NAR# 77907

How about masking tape wrap and a layer of glue in place of a CR? That should take up any slack I would think. Although, having the tubes resized does make sense in the fact you could make couplers out of them also.

CPMcGraw

01-15-2007, 11:21 PM

*Maybe ST-4 OD(.425) change to .51 to fit into a ST-5(.515)
*Maybe ST-6 OD(.626) change to .745 to fit into a ST-7(.715)

On the ST-4, you're describing a wall thickness of 0.0555", or just a fraction thicker than Carl's 0.05" fiberboard material used for centering rings. That's a very thick-walled tube, thicker even than Carl's LT series of tubes.

On the ST-6, using an OD of 0.710", the wall thickness becomes 0.058". Again, a very thick-wall tube.

I am narrowing each about .005 which is what Carl's HTC couplers are narrowed.

My reason are to easily fit the new tubes into existing tubes. Also I
like the ST-5 tubes from the SchoolYard Sounder design and would like
to use the 10mm motors in them easily. Also there are no nose cones for either
new tube and an CR that is .09 tall is just too small (ST-4 to ST-5) :( .

What are your thoughts on this?

I see your reasoning behind it, but I think you need to look at other possibilities for those centering rings instead of laser-cut fiberboard. Think about using 3/16" wide thick-wall spiral-wound tubes as centering rings. This is really all that the Estes rings, Apogee rings, and even some of Carl's rings, are. I would rather go this route than try to increase the wall thickness of the ST-4 or ST-6 series. Remember, fitting them inside ST-5 or ST-7 tubes is not their only application. These tubes could eventually have their own sets of turned components; you can "create" these components yourself in RockSim.

Give me some additional time, and I'll work up a full set of components around these tubes. The wall thicknesses of these tubes are "standard" in comparison to the other tubes; I'd really like to keep it that way if possible.

Carl@Semroc

01-15-2007, 11:52 PM

CPMcGraw

01-16-2007, 12:09 AM

Best guess for ST-4 is:

ST-4 0.406" ID 0.432" OD .013" Wall

10mm tube will be mfg at .3940" OD (10.0mm) because that is FAI minimum.

After pressing, it can expand to about .400". That leaves about .006 clearance. If it expands more, we will reduce starting size to wind up with 10.0mm.

That makes the centering rings .032" wall thickness for ST-5 (with .002" clearance)

CR-4-5 0 .434" ID .498" OD probably from fishpaper like HTC-5.

I was thinking along the lines of using the ST-4 tube for the 10mm motors, but you're describing yet another tube that's smaller than this. What exactly is going to be the OD for the 10mm motors? The casing OD would have to be smaller than 10mm to fit into a 10mm OD tube. I was under the impression that the motor casing itself was 10mm, but you're saying the FAI minimum is for the body tube itself, and thus the motor would be smaller.

A fishpaper centering ring would be nice and stiff, come to think about it...

Carl@Semroc

01-16-2007, 12:12 AM

Sorry. That was not too clear.

10mm ENGINE tube will be mfg at .3940" OD (10.0mm) because that is FAI minimum.

CPMcGraw

01-16-2007, 12:18 AM

Sorry. That was not too clear.

10mm ENGINE tube will be mfg at .3940" OD (10.0mm) because that is FAI minimum.

So, are you saying you want a tube that is larger than my ST-4 spec of 0.399" ID and 0.425" OD for use with these 10mm motors? A little more slip-clearance inside? I was trying to match the slip-clearances given for the ST-5...

CPMcGraw

01-16-2007, 05:38 PM

The attached files contain listings for the new Semroc ST-4 and ST-6 components, based on recent discussions. Please go through your current RockSim files (BHDATA, BTDATA, CRDATA, and TCDATA) and remove all references to earlier versions of these components before installing the new files. This is unfortunately a manual process using Excel (or Notepad); there is no automated way to remove old data from the database files yet. Leave all other Semroc component data as it is.

Save these four files in the ROCKSIM | DATA | NEW folder before running RockSim. The program will merge the data from these files into the master files of the same name for you.

I will try to develop NCDATA and TRDATA files (nose cones and transitions) shortly.

CQBArms

01-16-2007, 08:50 PM

Craig would you be able to adapt this to some of the larger motors?
Something is a "big D" would be awesome.

CPMcGraw

01-16-2007, 10:02 PM

Craig would you be able to adapt this to some of the larger motors?
Something is a "big D" would be awesome.

From one Craig to another...

Is this more satisfying to your hunger??? :D

Understand, I haven't started working on any 24mm or larger motors yet, but I gathered you were looking for something to give this design more "WOW" at the field. It's hard to beat 29mm "H" power for that...

CPMcGraw

01-16-2007, 10:14 PM

CQBArms

01-16-2007, 10:16 PM

Buhahahahaha. You are "da man"!

From one Craig to another...

Is this more satisfying to your hunger??? :D

Understand, I haven't started working on any 24mm or larger motors yet, but I gathered you were looking for something to give this design more "WOW" at the field. It's hard to beat 29mm "H" power for that...

CPMcGraw

01-16-2007, 10:56 PM

snaquin

01-17-2007, 07:08 PM

I tried this tonight and found it works without a problem. Instead of having to continually edit your component databases each time I bring out something new, create a new folder called "RockSim SVDT", then do a "Select All" of the folders and contents of your base RockSim installation. COPY these to the "RockSim SVDT" folder. Now, edit out everything that IS NOT Semroc from each of the CSV files. What this leaves you is a clean set of Semroc-only components to work with. You can leave the base RockSim folder alone, and use it for other projects. Create a new icon on the desktop pointing to the SVDT version, and now you've got separate "Standard" and "Semroc SVDT" installations to choose from.

I'm going to edit the SEMROC CSV files and get a clean set for everyone to work with, including all of the new components and (hopefully) all of the actual turned components on the website.

Great idea! Much better than having to continue editing a single file.

It probably goes without saying but I'll say it anyway for all of the SVDT members here; remember it's good practice to back up your entire RockSim folder every so often in case of hard drive failure. It does happen.

I also copy the CSV file I'm about to edit to a new directory prior to editing to keep in case of an accidental deletion of valid information. I won't need to worry about this anymore using your suggestion.

Thanks Craig

.

CPMcGraw

01-19-2007, 12:53 PM

snaquin

01-19-2007, 08:07 PM

I'm posting this here because of some special motor data used in the simulations. This revision of the Andromeda tweaks the fin shape a little (increases it outward a smidge), and trims down the shroud "coils". I still think RockSim is mis-calculating the effect these trims have on the simulations, because the only way to add them is as "fins".

Length: 27.95"
Diameter: 1.64" (ST-16 shrouds)
Fin Span: 5.859"
Weight: 1.95 oz

B4-4.......330'......Dv 13 FPS
B6-4.......337'......Dv 9 FPS
B14-4......344'......Dv 2 FPS
B8-4.......348'......Dv 2 FPS
B6Q-4......385'......Dv 2 FPS
B7-4.......456'......Dv 7 FPS
C6-5.......777'......Dv 6 FPS
C10-5......846'......Dv 9 FPS

All motors reach flight velocity on a standard (36" x 1/8") launch rod.

Do you think I need anything else on this model? I think the "coil detail" around the shrouds was much needed, even if it did knock off some of the upper-end performance.

Enjoy!

I think it looks great just how it is. If you wanted to add something perhaps one or two little corrugation wraps to break up the space between the nose cone and fin details. I've been looking at these on the Apogee site:

http://www.apogeerockets.com/vac-form_wraps.asp

Really though as far the the design I'd say it's good. With all that detail it's hard to believe it has a mass of just under 2 ounces.

A cool decal on that space would work just as well to finish it

.

CPMcGraw

01-19-2007, 10:48 PM

I think it looks great just how it is. If you wanted to add something perhaps one or two little corrugation wraps to break up the space between the nose cone and fin details. I've been looking at these on the Apogee site:

http://www.apogeerockets.com/vac-form_wraps.asp

Really though as far the the design I'd say it's good. With all that detail it's hard to believe it has a mass of just under 2 ounces.

A cool decal on that space would work just as well to finish it

.

Thanks, Steve. I was thinking along the lines of a decal of some sort, as I don't want to add any more weight to it. A wrap would be a little tight around that ST-7 main tube. I might have better results with wraps around those shrouds; it might satisfy my need for some raised details without incurring the fin penalty...

snaquin

01-19-2007, 11:07 PM

Thanks, Steve. I was thinking along the lines of a decal of some sort, as I don't want to add any more weight to it. A wrap would be a little tight around that ST-7 main tube. I might have better results with wraps around those shrouds; it might satisfy my need for some raised details without incurring the fin penalty...

The fact that it can be flown from a standard 36" rod with those motor choices is reason enough not to want to add any additional weight. I like the design. At 28" long with the fin span it's a nice looking rocket.

Ever since I read the post Bob Thomas made and saw what he did with that Orion clone I've had wraps on the brain :o I downloaded your BARCLONE / Semroc Orion file and I'm thinking hard about ordering the needed parts and just buying the wraps.

.

Mark+3

01-20-2007, 01:21 AM

CPMcGraw

01-20-2007, 06:34 AM

Nothing special about this one, but it's my first design post so I thought I'd throw it out here for you folks to check out. Please let me know what you think.

Semroc's Lil' Ivan is a great sport rocket suitable for small fields on A's and B's.
Here's my 80% downscale for 'T' size motors. Prototype is built; waiting for paint, pictures, and flight testing.

Mark,

Good looking downscale. One point of caution, however. Take careful note of the "MARGIN" value shown in the 2D line drawing. While the model as-configured might burn off enough mass before leaving the rod, and thus the margin value come up as a result, don't rely upon it happening every time. You need to re-distribute some mass, or add some ballast, toward the nose to get the margin at or above 1.00. That's the "magic number" to work toward, and models that have a margin of 1.00 or better usually fly the way they were intended to.

I played with the model (in RockSim) and found if you put 1/4 oz of ballast under the screw eye it will bring the margin back above 1.00 when using your selected motors at a penalty of lower performance. Tiny Ivan is a short-coupled design, and thus requires more ballast than a longer-body design. Stretching the body 1" eliminates the need for any ballast, however; if you're willing to accept a slight "out-of-scaleness" in the model, not adding any ballast keeps your performance numbers up.

Since we're in the SEMROC area of the forum, some of the "proposed" motor values might work even better than the standard-fare 13mm stuff we have right now...:D

Mark+3

01-20-2007, 01:35 PM

Mark,

Good looking downscale. One point of caution, however. Take careful note of the "MARGIN" value shown in the 2D line drawing. While the model as-configured might burn off enough mass before leaving the rod, and thus the margin value come up as a result, don't rely upon it happening every time. You need to re-distribute some mass, or add some ballast, toward the nose to get the margin at or above 1.00. That's the "magic number" to work toward, and models that have a margin of 1.00 or better usually fly the way they were intended to.

I played with the model (in RockSim) and found if you put 1/4 oz of ballast under the screw eye it will bring the margin back above 1.00 when using your selected motors at a penalty of lower performance. Tiny Ivan is a short-coupled design, and thus requires more ballast than a longer-body design. Stretching the body 1" eliminates the need for any ballast, however; if you're willing to accept a slight "out-of-scaleness" in the model, not adding any ballast keeps your performance numbers up.

Since we're in the SEMROC area of the forum, some of the "proposed" motor values might work even better than the standard-fare 13mm stuff we have right now...:D

A have read several references to keeping the stability margin at or above one BT diameter.
RockSim shows the Semroc Lil' Ivan at a margin of .62 on a C6-5 and .70 with an A8-3. I have flown the Lil' Ivan many times on Estes A, B, and C motors w/o a hint of instability.

***However, I am wondering if anyone has practical experience with other models that RockSim shows as having marginal stability.***

The 'T'iny Ivan sims at a margin of .95, a significant increase over the Lil' Ivan. So although it hasn't reached one caliber I have high confidence flight testing will go well. I will bring ballast just in case.

Pyro Pro

01-20-2007, 09:22 PM

Here's another design I created today. I couldn't think of a good name, so I just called it the "HiPerformance 2-Stage" for now. It's not really made for any of the new motors, but I thought it would be a neat design nonetheless. It's supposed to be somewhat reminiscent of a sounding rocket, red/white/black paint scheme with a roll pattern. The booster was interesting to make, because it had an ST-9 motor mount, but at the top had to transition to the ST-8 booster joining tube that supports the transition. ST-8 is too loose of a fit inside ST-9 to just glue them in, and too close of tolerances to support a centering ring (0.0425" on either side). It turns out that the inside of an HTC-9 tube coupler is the perfect size to slip over the outside of an HTC-8 tube coupler, so by gluing those together midway it is possible to transition between the two tubes. Also, to permit tumble recovery for the booster, the fins had to be mounted up 1.75" from the base of the booster tube, making the booster just barely unstable when loaded with an empty motor casing (The entire rocket is still 1.13 calibers stable with all motors loaded, no noseweight required). Sims out to just over 2400' with a D12-0 staging to a C6-7. Sustainer recovery is by a 2.5" by 25" crepe paper streamer, which gives a descent rate of ~27 FPS at landing (Although a 12" parachute with a large spill hole could also work).

----------

First number is just the sustainer, second number is for both stages:

Length: 21.8"; 30.8"
Diameter: 0.908" (ST-8); 1.34" (ST-13)
Fin Span: 3.408"; 5.34"
Weight: 1.23 oz; 2.48 oz

A8-3 (single stage) . . . . . . 250' . . . . . . Dv 11.6 FPS
C6-7 (single stage) . . . . . . 1358' . . . . . Dv 15.3 FPS
D12-0 ---> C6-7 . . . . . . . . . 2431' . . . . . Dv 11.7 FPS

Here it is:

Pyro Pro

01-20-2007, 09:28 PM

Here are pictures and a RockSim file of just the booster, for clarity. The RockSim file already has an empty motor casing mass object added to show the instability (21.5 grams).

Length: 9"
Diameter: 1.34" (ST-13)
Fin Span: 5.34"
Weight: 1.28 oz

Just a note: That little red thing that you can see rendered near the tip of the booster in the transparent image is something associated with the 0.0001" x 0.0001" nose cone that I had to put in for the sustainer to prevent the stability margin from being 'nan'. It is NOT any part of the booster (you can also see it in the 2D model as the skinny rectangle just behind the forward stage coupler).

CQBArms

01-20-2007, 09:32 PM

That is SICK! (in a good way)

I'm working on a two stage SLS SkyHook...I think it will be cool.
I want to build a couple and really test it.

CPMcGraw

01-20-2007, 09:35 PM

Here's another design I created today. I couldn't think of a good name, so I just called it the "HiPerformance 2-Stage" for now...

First number is just the sustainer, second number is for both stages:

Length: 21.8"; 30.8"
Diameter: 0.908" (ST-8); 1.34" (ST-13)
Fin Span: 3.408"; 5.34"
Weight: 1.23 oz; 2.48 oz

A8-3 (single stage) . . . . . . 250' . . . . . . Dv 11.6 FPS
C6-7 (single stage) . . . . . . 1358' . . . . . Dv 15.3 FPS
D12-0 ---> C6-7 . . . . . . . . . 2431' . . . . . Dv 11.7 FPS

How about "Hi-Per-2-S", or "Hypertuse"??? :rolleyes: :D

Do you have the "preliminary motor files" I posted a few days ago? Quite a few of the motors I speculated on are on Carl's list. Why not grab a copy of his early list and use those motors which now have matching ENG files for in your simulation.

Word of advice: Any deployment velocity over 20 FPS is asking for a shread of the parachute or streamer. Try to tweak your power to achieve a deployment velocity (Dv) of less than 20 FPS; below 10 FPS is even better, and lower still, the model will rarely suffer a zipper.

Pyro Pro

01-20-2007, 09:51 PM

I've got the motor list from a few days ago with just the smaller motors, but I'll go download the newer one and re-sim with some of the other motors.

Thanks for the feedback, I'll try to work on some of those other Dv's (the D12-0 to A8-5 didn't look too good to me either :eek: , or the B6-6).

Pyro Pro

01-20-2007, 10:11 PM

Ok, re-simmed with every combination of the newer motors. Some highlights:

C10 (18)-7 . . . . . . . . . . . .1484' . . . . . . Dv 0.7 FPS
D12-0 ---> B6 (18)-7 . . 1835' . . . . . . Dv 2.6 FPS
B6 (18)-5 . . . . . . . . . . . . . 627' . . . . . . . Dv 4.9 FPS

And the file:

CPMcGraw

01-20-2007, 10:38 PM

Pyro Pro

01-21-2007, 01:08 PM

Using some of the new motor files, I did a few more simulations with my Micro Hustler design. Most of the B motors could have done with some 0.5 second delay increments, (lots of 5.3, 5.5, 5.6's as optimal delays), but there were a few good flights. I also tested it on my interpretation of a 4.5" long, 20 n/s D5 motor.

B14 (18)-6 . . . . . . 777' . . . . . . Dv 10 FPS
B4 (18)-5 . . . . . . . 782' . . . . . . Dv 11 FPS
C10 (18)-7 . . . . . . 1574' . . . . . Dv 12 FPS

----------

CPMcGraw

01-22-2007, 07:10 PM

Fancy name for a simple 3FNC...

Makes good use of motors yet seen... :D

Length: 23.59"
Diameter: 0.908"
Fin Span: 5.9"
Weight: 1.21 oz

A8-3......250'......Dv 11 FPS
B4-5......586'......Dv 7 FPS
B6-5......596'......Dv 3 FPS
B8-5......607'......Dv 5 FPS

All motors reach flight velocity on a standard launch rod.

Enjoy!

Tau Zero

01-22-2007, 11:07 PM

A have read several references to keeping the stability margin at or above one BT diameter. [SNIP]

***However, I am wondering if anyone has practical experience with other models that RockSim shows as having marginal stability.***Read this, and let us all weep together in unison :( :

http://forums.rocketshoppe.com/showpost.php?p=9780&postcount=20

Notice the bit that mentions a margin of 0.95 on a C6-5. Make sure you don't overlook the reference to...

CARTWHEELS! :mad: :mad:

Yes, I've had real-life practical experience with this. :eek: Trust me. :mad:

Cheers,

James Pierson

01-23-2007, 09:46 PM

Well, I am a little slow (not playing dumb here) :o when it comes to adding new files and other computer stuff, but I finally got my files updates.

Here is my first design using the 15mm motors. I am just starting to realize the design implications that these motors and the choice of delays will have on future design. We may not have to do as much tweeking for stability and just tweek for the looks of the design. :cool: COOL!

I would like to take the time say a special THANKS! to Craig and Carl for thier hard work and leadership with this "Designer's Corner" thread. Without the motor and tube specs we would be behind the eight ball as it were when it comes to new design for these motors.

Thanks Agian and Enjoy, JP

James Pierson
NAR# 77907

Venus Explorer (15mm)
Launch guide length: 36.0000 In

MOTOR MAX. ALTITUDE DEP. VELOCITY
[A6-3]..........119.95801 Ft............16.4077 ft/s
[A8-3] .........136.62402 Ft............17.1787 ft/s
[A10-3].........142.47638 ..............19.6701 ft/s
[B4-4] .........389.77362 Ft............3.0033 ft/s
[B6-4] .........402.08661 Ft............8.5786 ft/s
[B7-5]..........580.05578 Ft............2.3424 ft/s
[B14-5] ........416.25000 Ft............12.3579 ft/s
[B6Q-5] ........472.59843 Ft............10.8417 ft/s

.

James Pierson

01-24-2007, 09:09 PM

Here is another design I call the Space Argosy which has no pesky paper transitions but has many centering rings. It has a retro look to it as well.

With an itch to build something lately I have been thinking about doing another prototype of one of our designs, but cannot make up my mind which one ;) to do. I will definetly have to convert many to all Semroc parts before I start. All you folks have seen the photo's of the prototypes that I have built on the 'Scrounged Thread". Well, all but one that needs some minor re-designing :D .

Do you folks have any favorites that you would like to see a real version of??

I am also thinking of posting a poll with a few designs listed and put it to a vote. What do you folks think??

With an itch to build something.

Enjoy and Thanks Again, JP

James Pierson
NAR# 77907

Space Argosy (15mm)
Launch guide length: 36.0000 In

MOTOR.........MAX. ALTITUDE........DEP. VELOCITY
[A6-3]..........118.86155 Ft............17.4803 ft/s
[A8-3] .........135.20669 Ft............18.3947 ft/s
[A10-3].........140.12270 Ft............21.4717 ft/s
[B4-4] .........365.96785 Ft............6.7546 ft/s
[B6-4] .........377.29331 Ft............0.7025 ft/s
[B7-5]..........528.91404 Ft............12.0403 ft/s
[B14-4] ........387.88714 Ft............11.3531 ft/s
[B6Q-4] ........436.95538 Ft............12.0275 ft/s

I really love these motors!

CPMcGraw

01-28-2007, 08:33 PM

James or Eric, have either of you tried the "pre-production" B14-3 or C10-4 motors on the Sabertooth? I think you'll like the results.

(Meggadogfighter, AKA Sabertooth)

B14-3......208'......Dv 5 FPS......Requires 22" of launch rod
C10-4......565'......Dv 10 FPS......Requires 18" of launch rod

Of the two motors, it's more likely we'll see the B14 in an 18mm package. Carl has already indicated the 18mm C10 might not be feasable, but if it could be done in a 21mm package, this design could be re-fitted. The C10 looks like the optimum choice.

James Pierson

01-28-2007, 08:54 PM

CPMcGraw

01-29-2007, 12:26 AM

I wanted something to use 15mm motors instead of 13mm, and I wanted to to take advantage of Carl's 0.05" fiberboard material for fins. This model tries to work in a number of advanced ideas, including a ringfin and some exposed centering rings. No, the ringfin does not have any internal pylons between it and the main body tube; it has the appearance of "floating". I think it turned out aestetically satisfying...

Length: 15.70"
Diameter: 0.908", 1.340" (ST-8 body, ST-13 ringtail)
Fin Span: 3.415"
Weight: 1.124 oz

A6-3......176'......Dv 7 FPS
A8-3......198'......Dv 9 FPS
B4-4......383'......Dv 19 FPS
B7-4......440'......Dv 16 FPS

All motors reach flight velocity on a standard launch rod.

Enjoy!

EchoVictor

01-29-2007, 09:27 AM

I have tried the 24m D12-3 and the E6-4 seem to work good. I kept this design in the "Scrounged" area for privacy ;) reasons since Eric was working on it as an 18mm design. Today I have invited Eric via Carl to join us here at SVDT. I hope thats alright with you folks.

Craig, please feel free to post the Rocksim file of Sabretooth with any motor version if you would.

James Pieson
NAR# 77907

Eric on board, here!

Thanks for the RockSim work on this. I'm planning on an 18mm mount since my home flying field just got cut in half (they're finally building their church, oh well...).

I'm still getting up to speed with this new forum. Am I reading this right that there are going to be B10 to 14 and C10 18mm motors? Sweet!

Later,
Eric

CPMcGraw

01-29-2007, 12:26 PM

Eric on board, here!

Thanks for the RockSim work on this. I'm planning on an 18mm mount since my home flying field just got cut in half (they're finally building their church, oh well...).

I'm still getting up to speed with this new forum. Am I reading this right that there are going to be B10 to 14 and C10 18mm motors? Sweet!

Later,
Eric

Actually, no... :(

The B14 looks like it will be produced as an 18mm in Carl's DECAP configuration. That means we get to choose the delay time in one-second increments...

The C10 is a bit problematic. Carl indicated it needs a larger casing to be reliable, so I'm hoping a compromise at 21mm is possible. The numbers in the "pre-production" list are simply copies of the available information transposed to the other case diameters. Apogee had that C10 in the 18mm casing, but it may not have been reliable.

If that 21mm version is possible, I'd consider building Sabertooth with a 21mm mount; anything larger would permit heavier motors, and that's too much weight in the wrong place for a short-coupled model.

Initiator001

01-29-2007, 12:31 PM

The C10 is a bit problematic. Carl indicated it needs a larger casing to be reliable, so I'm hoping a compromise at 21mm is possible. The numbers in the "pre-production" list are simply copies of the available information transposed to the other case diameters. Apogee had that C10 in the 18mm casing, but it may not have been reliable.

The Apogee C10 worked just fine. I've flown both C10s and C4s and never had any trouble (Other than getting the motors to ignite! :rolleyes: )

Bob

CPMcGraw

01-29-2007, 12:45 PM

The Apogee C10 worked just fine. I've flown both C10s and C4s and never had any trouble (Other than getting the motors to ignite! :rolleyes: )

Bob

That's good information, Bob. Maybe with time Carl can tweak the machine to get us a DECAP version in 18mm. I've got a design that is just begging for the C10, so he knows there's interest in it...:D

Carl@Semroc

01-29-2007, 01:08 PM

Apogee had that C10 in the 18mm casing, but it may not have been reliable.
The Apogee C4 and C10 are composite, so they won't have the same characteristics of BP.

CPMcGraw

01-29-2007, 03:05 PM

The Apogee C4 and C10 are composite, so they won't have the same characteristics of BP.

That would make a difference.

You indicated earlier a BP C10 in 18mm would be difficult if not impossible. Would an increase of 3mm be enough to create that motor (21mm) or are we limited to a minimum of 24mm before we could see one?

Carl@Semroc

01-29-2007, 03:15 PM

That would make a difference.

You indicated earlier a BP C10 in 18mm would be difficult if not impossible. Would an increase of 3mm be enough to create that motor (21mm) or are we limited to a minimum of 24mm before we could see one?a 21mm eninge would be about a C8 or C9 with about a 1.1 second burn.

James Pierson

02-03-2007, 09:02 PM

Here is another attempt at a mid-size (15mm) jet and I call it the Hyper Jett.
I would prefer this bird to be a little shorter but it just can't be done to get the proper static margin. Also a design note: The outter BT pods on the wings fit into a cut hole in the wing itself for ease of installation. A little inspiration from some of Craig's funky wing designs there :D .

Enjoy and Thanks Again, JP

James Pierson
NAR#77907

Hyper Jett (15mm)
Launch guide length: 36.0000 In

MOTOR........MAX. ALTITUDE........DEP. VELOCITY
[B4-3] .........265.01378 Ft............5.9382 ft/s
[B6-3] .........270.59777 Ft............10.4015 ft/s
[B7-5]..........362.70669 Ft............8.8274 ft/s
[B14-4] ........277.73327 Ft............11.8744 ft/s
[B2-3] ........ 315.57743 Ft............6.2477 ft/s

.

CPMcGraw

02-08-2007, 12:18 AM

Folks,

This has taken longer than I expected to get back to, but here's the complete body tube CSV file for every tube currently listed on the SEMROC website. It includes both the "Standard Tubes" (SEMROC/Centuri) and the "Classic Body Tubes" (Estes).

For your SVDT copy of RockSim, you need to REPLACE the existing BTDATA file with this one. For your base installation of RockSim, you need to edit out the existing SEMROC data from the BTDATA file, then save this new file in the DATA | NEW folder before cranking up RockSim. Using Excel is really the easiest way to do the editing, as you can see everything that is contained in the file. It's easy to locate duplications in the database using a spreadsheet.

CPMcGraw

03-15-2007, 07:53 PM

Coming across as a combination of the Nomad, the Payloader II, and the ARCON HI, the Nova and Nova-Hi have good looks and are functional as payload lofters. I tried to optimize the designs for 0.5 oz payloads, so keep that in mind when you look at the simulation runs.

Be aware that both models currently require a 3.5" length of ST-10 to use as a payload compartment, as we don't have the CPT-1035 yet. I have drawn it in as "something yet to come, hopefully, one day soon". That's one reason why they're being released here on SVDT and not on the public forum. I also ran the simulations with NYA Semroc motors...

SINGLE STAGE Nova

Length: 20.70"
Diameter: 1.04" (ST-10)
Fin Span: 3.54"
Weight: 1.35 oz (empty)

A8-3......0.0 oz payload......202'......Dv 8 FPS.......36" rod
A8-3......0.5 oz payload......140'......Dv 19 FPS......40" rod
B6-4......0.0 oz payload......475'......Dv 14 FPS......36" rod
B6-4......0.5 oz payload......380'......Dv 12 FPS......36" rod
C6-5......0.0 oz payload......990'......Dv 14 FPS......36" rod
C6-5......0.5 oz payload......895'......Dv 17 FPS......36" rod

The A8-3 carrying the payload is not a recommended configuration. Only use this motor for initial test flights with no payload installed.

TWO-STAGE Nova-Hi

Length: 23.95"
Diameter: 1.04" (ST-10)
Fin Span: 3.54"
Weight: 1.93 oz (empty)

B14-0 / C6-6.........0.0 oz payload......1333'......Dv 22 FPS......36" rod
B14-0 / C6-6.........0.5 oz payload......1300'......Dv 14 FPS......36" rod
3/4C19-0 / C6-6......0.0 oz payload......1456'......Dv 18 FPS......36" rod
3/4C19-0 / C6-6......0.5 oz payload......1450'......Dv 14 FPS......36" rod

Yes, the performance is nearly equal with or without the payload!

Enjoy!

Mark II

03-15-2007, 09:16 PM

CPMcGraw

03-15-2007, 09:45 PM

Hello, SVDT.

I have a trial copy of Rocksim and want to try out some design ideas that I have, using Semroc components, of course. No Semroc components are listed in the trial copy's database, but I assume that I can add them in. Is there an exisiting database of current Semroc components available in Rocksim format that I can append to the default parts database, or will I need to build my own?

Mark

It's a "Work In Progress", Mark, but some of the components are available to SVDT members. My message ahead of the Nova in this thread has a file containing the body tube CSV. I think I've posted the nose cone data somewhere on this thread, it may be a few messages back.

ADDENDUM: Here's the link for some of the files: Message (http://forums.rocketshoppe.com/showpost.php?p=15332&postcount=50)

Mark II

03-15-2007, 10:41 PM

Mark II

03-16-2007, 12:18 AM

It's a "Work In Progress", Mark, but some of the components are available to SVDT members. My message ahead of the Nova in this thread has a file containing the body tube CSV. I think I've posted the nose cone data somewhere on this thread, it may be a few messages back.

ADDENDUM: Here's the link for some of the files: Message (http://forums.rocketshoppe.com/showpost.php?p=15332&postcount=50)

Thanks, Craig; this is just what I was looking for. As you can probably tell, I'm a Rocksim newbie. Shortly after I posted, I figured out how to add custom components to the database. :o

Mark

James Pierson

03-16-2007, 08:49 PM

Here is another SVDT design called the Baracuda, with flight specs on the new motors. I have been working on this one a while and am finally happy with the results. A few weeks ago at work we went to 60 hours a week so I haven't had much time for the fun things in life. Also the weather is starting to mellow out but the only day I have to myself is Sunday.

I am working on a 24mm version of this design and am wondering if Carl will also be making some mid power motors (D12, E-6)?

Enjoy and Thanks Again, JP

Baracuda (SVDT 18mm)
Launch guide length: 36.0000 In

MOTOR.................MAX. ALTITUDE...........DEP. VELOCITY
[B4 [18mm]-3}.........299.04921 Ft............5.4768 ft/s
[B6 [18mm]-4] ........308.09514 Ft............14.7346 ft/s
[B8 [18mm]-4].........305.07251 Ft............9.3283 ft/s
[B14 [18mm]-4]........312.26411 Ft............3.7712 ft/s
[B16R [18mm]-4].......293.81890 Ft............5.9176 ft/s
[7/10 C3R [18mm]-3]...430.04593 Ft............10.0871 ft/s
[3/4 C19 [18mm]-5]....519.62599 Ft............5.5239 ft/s
[C6 [18mm]-5].........708.93701 Ft............13.4748 ft/s

James Pierson
NAR# 77907

.

CPMcGraw

03-30-2007, 01:25 PM

I almost goofed and sent this to the "Scrounged" thread by mistake. :eek:

This plan uses our new, soon-to-be-seen motors to achieve safe deployment velocities. It also fits into the VR category of designs, remaining under the 800' max altitude when using a "C" motor.

Length: 23.20"
Diameter: 1.04" (ST-10)
Fin Span: 3.04"
Weight: 1.32 oz

A8-3..........165'......Dv 17 FPS......30"
A5-3..........186'......Dv 11 FPS......20"
3/4B7-3.......288'......Dv 10 FPS......9"
B8-3..........360'......Dv 19 FPS......26"
B6-3..........376'......Dv 14 FPS......18"
7/10C3-3......491'......Dv 10 FPS......30"

The ringfin pulls a lot of drag, as you can see by the max altitude values. It's not a fancy design, compared to others, but it's simple and flyable; and that's what I think we still fly more often.

Enjoy!

James Pierson

03-30-2007, 06:35 PM

CPMcGraw I almost goofed and sent this to the "Scrounged" thread by mistake.

I have almost done the same Craig :eek: . To help solve the confusion I have been including in the file name SVDT (15-18mm). I have also created a seperate file to store all other SVDT file.
The biggest confusion for me is which Rocksim files I am still working on, whiich ones are ready to post, the junkyard files, and already posted :confused: . Too many folders!

James Pierson
NAR# 77907

CPMcGraw

03-30-2007, 07:39 PM

Another VR-class ringfin model. This one has a payload compartment, so the following simulations should be considered without payload.

Length: 21.20"
Diameter: 1.04" (ST-10)
Fin Span: 3.26"
Weight: 1.43 oz

A5-3...........177'......Dv 11 FPS......20"
3/4 B7-3.......281'......Dv 10 FPS......8"
B14-4..........353'......Dv 13 FPS......19"
3/4 C19-4......473'......Dv 8 FPS.......15"

Enjoy!

CPMcGraw

03-30-2007, 07:48 PM

I have almost done the same Craig :eek: . To help solve the confusion I have been including in the file name SVDT (15-18mm). I have also created a seperate file to store all other SVDT file.
The biggest confusion for me is which Rocksim files I am still working on, whiich ones are ready to post, the junkyard files, and already posted :confused: . Too many folders!

James Pierson
NAR# 77907

You're just dealing with folders? :rolleyes:

I have one entire 30GB partition on my hard drive set aside for rocketry-related stuff, and even then there are some things located on other partitions. :eek: One day, when it comes time to clean out the munge again on this box, I'll have to bring everything back together under a single partition. What I really need to do is set up a NAS box (network area storage) and move all of this over to it. That way I can access it from all of my computers.

The SVDT mark in the name is a good idea, though. It would help remind me which ones are for "private" release and which ones are for "public" release.

CPMcGraw

04-05-2007, 02:39 PM

This is another two-stage design similar to the Nova and Nova Hi, except in the larger ST-13 size, and it accepts long 24mm motors. Additionally, it requires a large clear payload tube which is not available just yet; this can be swapped out with a length of ST-13 at present.

Length: 34.40"
Diameter: 1.34" (ST-13)
Fin Span: 4.34"
Weight: 2.83 oz

Selected simulation runs:

7/10 C3-0 / 7/10 C3-4......886'......Dv 3.3 FPS......48" x 3/16" rod
B14-0 / C6-5...............971'......Dv 6.5 FPS......36" x 3/16" rod
3/4 C9-0 / C6-5...........1083'......Dv 3.8 FPS......36" x 3/16" rod
D12-0 / C6-5..............1477'......Dv 5 FPS........48" x 3/16" rod
E9-0 / C6-5...............1912'......Dv 6.2 FPS......48" x 3/16" rod

Payload section is empty on these flights. With the right motors, this might make a great BoosterVision lofter. Which reminds me, I need to revise the motor files soon and try out the new motors in the Cherokee Double-D...

Enjoy!

Pyro Pro

04-07-2007, 10:51 PM

Ok, another one from me. Here's another (semi, +- ~.1") scale model, the AIM-120 AMRAAM air-to-air missile. A few notes about the design:

1. Requires a few minor custom parts, a 5" piece of ST-13, and CR-1013 Centering rings to go from ST-13 to ST-10.

2. Although RockSim automatically does this, the aft fins should NOT be blended in with the transition, rather the root edge should be flat for its entire length.

3. Requires 20 grams of noseweight to ensure greater than 1 caliber stability with heavier motors.

4. Conduit is a slice of ST-5 (and the end DOES blend in with the aft transition), so the mass overide of the item has been slightly lowered to account for the missing material.

5. The motor mount was made 6" long to allow for the use of D5 motors.

6. As an afterthough, a baffle unit could be installed against the top of the ST-10 stuffer tube.

7. Scale reference: Peter Alway's scale data page (http://yellowjacketsystems.com/alway/images/amraam.gif).

---+++---+++---+++---+++---+++

Length: 27.55"
Diameter: 1.34" (ST-13)
Fin Span: 4.8854"
Weight: 3.87 oz

Selected simulation runs:

B8-3 . . . . . . . 153' . . . . . . Dv 9.3 FPS . . . . . 36" x 1/8" rod
B14-3 . . . . . . 157' . . . . . . Dv 4.6 FPS . . . . . 36" x 1/8" rod
B7-3 . . . . . . . 213' . . . . . . Dv 1.8 FPS . . . . . 36" x 1/8" rod*
C10-5 . . . . . . 553' . . . . . . Dv 9.5 FPS . . . . . 36" x 1/8" rod

* The simulation says that with the B7, safe minimum velocity (44 FPS) wasn't reached until a bit over 38" of guidence, so a 40" - 48" rod might be a bit safer. This wasn't a problem with any of the other motors.

Enjoy.

CPMcGraw

04-10-2007, 01:39 PM

Nothing major, and maybe whacked out when compared to what we eventually see in the new motors. Some of the low-end motors have been tweaked to resemble end-burners, which I suspect they will be.

All speculation, and subject to change... :D

CPMcGraw

04-10-2007, 01:56 PM

Model should be painted solid black with narrow, evenly-spaced vertical pinstripes on the body, and similar pinstriping following the leading edges of the fins...

Length: 14.52"
Diameter: 1.04" (ST-10)
Fin Span: 5.04"
Weight: 1.03 oz

1/2 A6-3......115'......Dv 16 FPS
A4-3..........150'......Dv 9 FPS
3/4 A6-3......212'......Dv 9 FPS
A5-4..........331'......Dv 4 FPS
A8-4..........333'......Dv 2 FPS
B16-6.........726'......Dv 12 FPS
B4-5..........758'......Dv 2 FPS
B8-6..........759'......Dv 16 FPS
B14-6.........761'......Dv 11 FPS
B6-5..........774'......Dv 12 FPS
C6-6.........1412'......Dv 4 FPS......48" x 3/16" rod required

All motors except the C6-6 can launch from a standard 36" x 1/8" launch rod. The design is shown with a 1.5" x 1/8" launch lug. This is a performance demonstrator, and should make a good flying model once the new motors are available. Current Estes motors are not optimized in their delay times for this model.

Enjoy!

CPMcGraw

04-15-2007, 11:16 AM

Not to be confused with the Hornet V design from 2003, which was a futuristic rendition of the F-18...

This is a simple stepped-diameter design, with the fin shape and size picked by RockSim (default size and shape for custom fins). Using the proposed new motors achieves some great results.

Length: 22.70"
Diameter: 1.04" (ST-10)
Fin Span: 5.20"
Weight: 1.32 oz

A8-4...........262'......Dv 12 FPS
3/4 B7-5.......471'......Dv 16 FPS
B7-5...........640'......Dv 10 FPS
B8-5...........644'......Dv 8 FPS
B14-5..........647'......Dv 12 FPS
B6-5...........655'......Dv 2 FPS
7/10 C3-5......876'......Dv 4 FPS

All motors above reach safe flight velocity on a standard 36" x 1/8" launch rod.

Enjoy!

Pyro Pro

04-15-2007, 04:14 PM

Another small-field design. This model has a small (ST-10) payload section suitable for mini-altimeters, transition down to ST-8 for the rest of the rocket. There are 4 "radiator" fins in between the main ones, one of which acts as a standoff for the launch lug. Could also use 18mm motors if more performance or use of a shorter launch rod is desired, but 13mm's should be fine in most cases.

Length: 15.225"
Diameter: 1.04" (ST-10 payload); 0.908" (ST-8 main body)
Fin Span: 3.908"
Weight: 1.10 oz

3/4 A3-3 . . . . . . . . . . 202' . . . . . . Dv 3 FPS . . . . . 48" x 1/8"
3/4 B3-5 . . . . . . . . . . 546' . . . . . . Dv 10 FPS . . . . 48" x 1/8"
A10-4 . . . . . . . . . . . . 334' . . . . . . Dv 4 FPS . . . . . 36" x 1/8"
B3-5 . . . . . . . . . . . . . 770' . . . . . . Dv 11 FPS . . . . 48" x 1/8"

Enjoy

Pyro Pro

04-30-2007, 05:46 PM

Here's another one...
This is based off of ST-16, with a transition to ST-13 for the last 0.5" of the rocket, and a 24mm motor mount. The ring fin adds a lot of drag, making the optimal delay on almost all the motors tested (from C11 to F21) about 3 seconds. This would be a good demo rocket, and could benefit with some new, higher-thrust 24mm motors (though safe speed is reached in 36" by all motors). Recovers on a 16" parachute with a 2" spill hole.

Length: 17.3"
Diameter: 1.64" (ST-16)
Fin Span: 5.64"
Weight: 2.08 oz

D12-3 . . . . . 500' . . . . . Dv 3.3 FPS . . . . . 3/16" x 36" rod
E9-4 . . . . . . 789' . . . . . Dv 28.1 FPS* . . . 3/16" x 36" rod

*Could do with a 3 second delay, Dv would then be 0.2 FPS.

Pyro Pro

04-30-2007, 05:55 PM

Now, moving to the complete opposite side of the board, here is a very high-performance, minimum-diameter model for 24mm motors. This is a scaled up version of the design from The Handbook of Model Rocketry (originally for 13mm motors). This one could really benefit from some long-burning (4+ seconds) D and E motors to achieve extreme (for a black-powder powered model rocket) altitudes. Recovers on (2) 30" crepe streamers.

Length: 15"
Diameter: 0.998" (ST-9)
Fin Span: 4.998"
Weight: 0.78 oz

D12-7 . . . . . 2118' . . . . . Dv 12.2 FPS . . . . . 3/16" x 36" rod
E9-8 . . . . . . 3119' . . . . . Dv 3.5 FPS . . . . . . 3/16" x 36" rod

CPMcGraw

04-30-2007, 06:56 PM

David,

If I've not said it before, I appreciate your contributions to the design threads. I really enjoy seeing everyone's creativity through these RockSim plans. We have a deep pool of talent here, and that's a good thing for both SEMROC and the hobby.

Once SEMROC gets the motors into production, I'll be able to send these designs to BARCLONE for general web posting (if that's OK with you). Anything you want to keep out of the public for development, just shout and I'll hold it out.

CPMcGraw

05-22-2007, 12:35 PM

Almost goofed and posted this in the "Scrounged" thread... Yikes! :eek:

These two designs are part nostalgic, part whimsical, and were inspired by Gravitybandit Bob's posts about the old Centuri plans. In particular, the Micro-Probe...

I combined elements of the Estes Mini Bertha, the Estes Apogee II, and the Centuri Micro Probe to reach this design. The model is intended for the planned 13mm motors from Semroc, which explains why it was almost a mistake posting to the other thread. This model proves you don't need large 18mm motors to get great performance, you just need the right motors to do the job.

Mk I specs:

Length: 14.15"
Diameter: 0.736" (BT-20)
Fin Span: 4.49"
Weight: 0.6 oz

A10-0 / 1/4 A4-5.......625'......Dv 7 FPS
A10-0 / 1/2 A3-6.......823'......Dv 11 FPS
A10-0 / 3/4 A3-6......1005'......Dv 4 FPS
A10-0 / A3-6..........1164'......Dv 6 FPS

All motors reach flight velocity on a standard 36" x 1/8" launch rod.

Mk II specs:

Length: 18.65"
Diameter: 0.976" (BT-50)
Fin Span: 4.49"
Weight: 0.84 oz

A10-0 / 1/4 A4-5......487'......Dv 10 FPS
A10-0 / 1/2 A3-5......646'......Dv 5 FPS
A10-0 / 3/4 A3-5......798'......Dv 15 FPS
A10-0 / A3-6..........934'......Dv 12 FPS

All motors reach flight velocity on a standard 36" x 1/8" launch rod.

Enjoy!

Pyro Pro

05-22-2007, 06:08 PM

Hmmm... Well, I guess I should post another one too :D

Originally this was going to be a purely hypothetical design, but now that I'm done I'm thinking I might just build one. It's a 2-stage rocket with about average sport rocket performance (ie, small field flights single-staged on A's and B's, bigger field flights on C's and 2-stage flights). The design uses a unique (I think...) interlocking booster design. Rather than using a recessed sustainer motor tube and hollow tube coupler, the fins on the sustainer wrap around the outside of the booster, and then an extended motor tube fits through 2 closely positioned centering rings. Attached to the bottom of one of these rings is a sleeve coupling the two motor tubes, ensuring that the booster motor blowby has no chance of missing the sustainer nozzle. Due to the tight diminsional tolerances in that area, a new length of ST-7 would need to be manufactured, with a 7.125" length.

Optimus Prime
Length: 28.1"
Diameter: 1.34" (ST-13)
Fin Span: 6.34"
Weight: 2.57 oz

A few flight results (many more in the .rkt file [hence it's large size])

A4R [18mm] - 2 . . . . . . . . . . . . . . . . . 86' . . . . . Dv 1.44 FPS
B4 (18) - 4 . . . . . . . . . . . . . . . . . . . . . . 428' . . . . Dv 4.52 FPS
C10 (18) - 6 . . . . . . . . . . . . . . . . . . . . . 1042' . . . Dv 6.29 FPS
3/4 C19 - 0 --> 7/10 C3R - 5 . . . . . . 1185' . . . Dv 7.48 FPS
3/4 D6 - 0 --> D5 [18mm] - 7 . . . . . 2602' . . . Dv 17.67 FPS

Enjoy!

CPMcGraw

05-22-2007, 06:21 PM

Optimus Prime
Length: 28.1"
Diameter: 1.34" (ST-13)
Fin Span: 6.34"
Weight: 2.57 oz

A few flight results (many more in the .rkt file [hence it's large size])

A4R [18mm] - 2 . . . . . . . . . . . . . . . . . 86' . . . . . Dv 1.44 FPS
B4 (18) - 4 . . . . . . . . . . . . . . . . . . . . . . 428' . . . . Dv 4.52 FPS
C10 (18) - 6 . . . . . . . . . . . . . . . . . . . . . 1042' . . . Dv 6.29 FPS
3/4 C19 - 0 --> 7/10 C3R - 5 . . . . . . 1185' . . . Dv 7.48 FPS
3/4 D6 - 0 --> D5 [18mm] - 7 . . . . . 2602' . . . Dv 17.67 FPS

Enjoy!

David,

One point to remind you about, which still occasionally catches me by surprise -- watch the Flight Data Simulation Results (double-click one of the simulation runs), and look carefully down the list at the "Launch Guide Data" field.

Note this example line from your 3/4 B3R-3 flight:

"Minimum velocity for stable flight reached at: 50.0882 In. "

It means you'd need a 60" long rod to be safe. In other words, it's not really achievable on this motor.

RockSim can sometimes give very rosy data for a simulation, making you think you've found a great motor. This is where it bites you in the ... asperations...:o

Interesting design, otherwise. I've got to study it some more...

Thanks!

Pyro Pro

05-22-2007, 10:58 PM

CPMcGraw

05-22-2007, 11:10 PM

Thanks for the reminder, I usually try to check, but often forget :o . You'd probably only want faster burning motors for this one anyway, especially in 2-stg configuration.

It occured to me that drag separation might become a problem with some of the larger/faster burning booster motors... all that flat surface area on the front of the booster gives it a rather high drag coefficient. Then again, if it goes fast enough, maybe the air would slipstream right over the gap, generating a vacuum and thus holding the booster on until sustainer ignition. Or maybe not. There's one [easy] way to find out . . .

As long as the booster hangs around to light the sustainer, that's tight enough. Stine suggested the friction fit should be just enough to keep the sustainer in place if you hold the booster upside down without it falling off. Not enough to bind, not too loose to slip off without a little help.

Pyro Pro

05-22-2007, 11:19 PM

Then I guess it should work... I'll just have to check tightness and add tape if necessary.

On the previous note of launch rod length, I went ahead and made a list of the motors from the simulation that are either: Not reccommended, <more emphasis> NOT reccomended, or recommended only under certain conditions:

3/5 B3R - 3: Not reccommended
Minimum velocity for stable flight reached at: 50.0882 In.

3/4 C6 - 5: Only reccommended under the condition that the flyer has a 48" launch rod
Minimum velocity for stable flight reached at: 46.7165 In.

3/4 D6 - 6: NOT reccommended
Minimum velocity for stable flight reached at: 83.6217 In.

D5 - 6: NOT reccommended
Minimum velocity for stable flight reached at: 112.4839 In.

3/4 D6 - 0 --> D5 - 7: NOT reccommended
Minimum velocity for stable flight reached at: 117.4807 In.

Pyro Pro

06-04-2007, 03:37 PM

Time for a new design:

The Talos, a 7x 18mm cluster rocket, styled after the Saturn 1B with its scalloped transition. This would be a very good candidate for scale-like decals, graphics, etc. Needs about 3/4 oz of noseweight to be stable according to Barrowman on a full loadout of C6's, but only .18 oz according to the RockSim method. A note about the file: The 1/16" thick launch lug standoff (that allows the launch lug to be glued in between two tubes, rather than in-line with them) should be positioned 1" aft of where it is located in the file. The screenshots show the proper positioning, but in order to get valid simulation results (ie, not "nan"), the part must be completely within the diminsions of its owning part, which is the cardstock tube underneath the main transition (when you open the file it is in the "wrong" physical position). For ejection charges, a "Hydra 7" approach could be taken, with all or as many outboard tubes as you want being blocked, and the remaining open tubes (if any) venting into the central tube (although probably would require extra reinforcement in the transition area).

Length: 26.033"
Diameter: 2.283" (3x 0.759 (ST-7) + 0.006" for cardstock)
Fin Span: 5.283"
Weight: 3.97 oz

----- ----- -----

(6x) 3/4 B7-5 . . . . . . 692' . . . . . . Dv 3.89 FPS . . . . . . 3/16" x 36" rod
(6x) B6-5 . . . . . . . . . . 784' . . . . . . Dv 2.38 FPS . . . . . . 3/16" x 36" rod
(6x) 3/4 C19-6 . . . . . 1167' . . . . . Dv 0.99 FPS . . . . . . 3/16" x 36" rod
(6x) C10-6 . . . . . . . . . 1507' . . . . . Dv 2.61 FPS . . . . . . 3/16" x 36" rod

For some reason, the 2D image does not want to upload with the other images, even when I try to upload it afterwards, so I'll attach it in another post.

Enjoy

Pyro Pro

06-04-2007, 03:41 PM

2D image:

(turns out that the file, though it had been exported as a .png, was pretending to be a bitmap at 1.38 MB. I opened it in paint and simply saved it again as a png, which reduced the file size to a much more respectable 14kb).

James Pierson

06-04-2007, 08:51 PM

Wow David, great design and even better Dv's. I found another design that I do not believe has been done if you are into scale. I think it is called the Exos.

Keep up the great designs, JP.

James Pierson
NAR# 77907

CPMcGraw

07-22-2007, 09:09 PM

This is a work-in-progress, since the nose cone still needs to be plugged into the Krellvenator :D , but it really shows what can be done on 13mm motors. The only current motor available is the Estes A3-4T, but the performance numbers are excellent.

This design will be part of the "Schoolyard Sounders" series.

An early designation for the nose cone might be "BC-1067NS". The actual length is 6.68". In the RKT file, it shows BC-10700NS, so the final call is not yet etched in stone (or balsa...).

[Late addendum] The sustainer is shown as 8.5", but should actually be 8.25". I forgot to remove the transition length from the total length. All other components remain as shown, and the performance remains the same.

The scale factor is 15.87, based on the Stine line drawing from 1967. Details that might be found in a larger scale can be duplicated in label stock and applied after the primer has been sanded.

Length: 15.11" (Corrected)
Diameter: 1.11" (Nose Cone; ST-10)
Fin Span: 3.76"
Weight: 0.68 oz (Corrected)

1/2A3-3T (DECAP)......185'......Dv 2.2 FPS
3/4A3-3T (DECAP)......310'......Dv 8 FPS
A3-4T.................475'......Dv 7 FPS

All motors reach flight velocity on a 36" x 1/8" launch rod.

Enjoy!

CPMcGraw

07-23-2007, 07:17 PM

This is a smaller Nike-Smoke for ST-8 body tubes. The scale-down value is 18.17 of full-size. I chose to use a streamer instead of a parachute since the upper altitudes are quite high for a model this size. The deployment velocities are also high for the two lower-power motors.

A nose cone still needs to be programmed into Carl's machine, but a preliminary designation might be BC-859NS. The overall length of this cone is 5.87" from absolute tip to the bottom of the transition.

The ST-873 sustainer tube should be shortened to 7.2", but I chose to leave it at the stock component length of 7.3" for simplicity.

A small 0.05 oz ballast (washer) needs to be added under the screw eye as ballast, to compensate for the marginal static number when using A3 and A2 motors.

Length: 13.13"
Diameter: 0.97" (BC-859; ST-8)
Fin Span: 3.31"
Weight: 0.59 oz

1/2A3-4......245'......Dv 18 FPS
A10-5........555'......Dv 20 FPS
A3-5.........575'......Dv 14 FPS
A2-5.........670'......Dv 12 FPS

Enjoy!

CPMcGraw

08-10-2007, 11:33 AM

snaquin

08-15-2007, 09:16 PM

Another Tau-ish design that manages to require exclusively the SEMROC line of motors :D :cool: , and DECAPs at that...

I call this one ZONDAKHOD...

Length: 17.95"
Diameter: 1.64" (ST-16 shroud)
Fin Span: 4.34"
Weight: 0.93 oz

A5-4.............355'......Dv 3 FPS
A8-4.............355'......Dv 5 FPS
3/4 B7-5.........585'......Dv 5 FPS
B14-5............650'......Dv 10 FPS
B3R-5............720'......Dv 7 FPS
B6-5.............770'......Dv 10 FPS
7/10 C3R-5......1000'......Dv 2 FPS
3/4 C19-6.......1030'......Dv 2 FPS

All motors reach minimum flight velocity on a standard 36" x 1/8" rod.

Enjoy!

Nice design Craig, looks like a 2-stager. How in the world did you come up with the name ZONDAKHOD? It sounds Eskimo-ish ;)

Are the Semroc Component files and preliminary Semroc motor file on page 5 of this thread the latest versions? Have you posted anything on the nose cones and transition files that I may have overlooked? I had to reinstall RockSim and I'm trying to get it back where I had it.

I've been pressed with work but I'd like to get back to some RockSim designing.

Thanks!

.

CPMcGraw

08-15-2007, 10:05 PM

Nice design Craig, looks like a 2-stager. How in the world did you come up with the name ZONDAKHOD? It sounds Eskimo-ish ;)

Are the Semroc Component files and preliminary Semroc motor file on page 5 of this thread the latest versions? Have you posted anything on the nose cones and transition files that I may have overlooked? I had to reinstall RockSim and I'm trying to get it back where I had it.

I've been pressed with work but I'd like to get back to some RockSim designing.

Thanks!

.

Steve,

I've been a bit slack in updating the components lists. They're something I need to get back to. The motor list is "complete" in the sense that I've included everything 18mm and under that Carl mentioned in the master line up. I'm not absolutely sure the curves are accurate, but they do fit the impulse parameters. Probably need a little tweaking to get them spot-on.

The ZOND part of the name was what the Russians named some of their early probes (http://www.lpi.usra.edu/expmoon/zond/zond.html). The KHOD part comes from Lunakhod (http://www.aerospaceguide.net/spacecraft/lunakhod.html), which was their name for a wheeled moon lander that touched down about the same timeframe as Apollo 12-13.

barone

08-16-2007, 07:36 AM

At NARAM, Carl showed me some of his prototype motor casings (ok markings wrapped around Estes motors) and possible shipping containers. Sweet. Looking forward to the first shipment.

Pyro Pro

01-12-2008, 11:24 PM

The Tetraphelion

A nice, fast, somewhat high-performance clustered, two-stage model with a payload. Sustainer is ST-10 based, booster is ST-20 and contains a 4x 18mm cluster. The sustainer is powered by a single 18mm motor. It uses 3/16th inch launch lugs, due to the potential 40Ns full-E power that it could have on takeoff with a full load of "C"s in the booster. The launch lug on the sustainer is mounted on a 1/2" standoff, which was large enough that I decided to just put another one on the other side and pretend it was just another set of fins. I'm not sure whether the half inch offset on such a small tube will have any levering effect during the guided portion of single-staged flight, but if it did it wouldn't be hard to just install another launch lug further up the tube to prevent this. Static stability margin looks okay for most motor choices (without added noseweight), the lowest would be something like a 1/4A in the sustainer with 4 C's in the booster, which gives a ~0.6 margin. In most ideal cases it is in the 0.8 - 1.2 range. RockSim says that the booster, despite its stable-looking design, should have close enough to neutral stability with expended engine casings loaded to allow it to tumble. I'm thinking that some sort of cone-type structure (with a base at the forward end of the motor mount, with an O.D. of 2", tapering up towards the ST-10 tube at the top of the booster) within the booster should be used (made of aluminum foil/Nomex paper, or something else flame resistant) to duct the booster gasses through to the sustainer through the ST-10 tube, and also to get rid of any corners where black powder soot could build up inside the booster. In the current design the ST-10 tube is 3" long, the shortest available one. A shorter tube (2", for example) would allow for a longer cone, to be used, and therefore make it a bit easier to the booster gasses and flaming bits to get to the upper stage (if my logic is correct here). Excess gas could vent through the small opening in between the four booster tubes, and if more venting was neccesary, through smaller openings made on the outsides of the centering rings (see Texas Firefly). I have the recovery system for the sustainer at the moment to be a 12" parachute with a generous spill hole cut out, but it probably would be wise to switch to a streamer due to the ~2500'+ altitude this design could potentially reach (plus, all balsa stock used is 3/32"- 0.09375", so the sustainer fins could probably survive a faster-than-normal descent).

Whew. That took a little longer than I thought. Now, the design:

Length:::: 25.4" --- (w/Booster) | 17.9" --- (Sustainer)
Diameter:: 2.04" --- (Booster) ||| 1.04" --- (Sustainer)
Fin Span:: 8.04" --- (Booster) ||| 3.54" --- (Sustainer)
Weight:::: 3.04 oz - (w/Booster) | 1.29 oz - (Sustainer)

A8 [18mm] - 4 ........................ 267' ..... Dv 11 FPS ..... 18"
B8 [18mm] - 5 ........................ 645' ..... Dv 7 FPS ...... 25"
C6 [18mm] - 6 ....................... 1255' ..... Dv 7 FPS ...... 37"
4x C6 [18mm] - 0, C6 [18mm] - 7 ..... 2603' ..... Dv 12 FPS ..... 34"

Enjoy.

Ltvscout

01-12-2008, 11:29 PM

The Tetraphelion
Whoa! Like a Quad Laser-X!

Pyro Pro

01-12-2008, 11:45 PM

This is what I'm thinking of, if it helps:

(and thanks, Ltvscout)

CPMcGraw

01-12-2008, 11:56 PM

The Tetraphelion...

Impressive!

Concerning those launch lugs, did you try using two on just the booster?

This might be an interesting project for a micro electronics ignition system. A booster with 4xC casings in a tumble is still going to have a lot of inertia when it hits. Probably enough to knock off a fin or two. I think even a small 12" plastic chute might be useful to prevent landing damage.

Wonder how it might work if you connected just two of the motor tubes to the sustainer, and used the other two to eject the transition shroud section a few seconds later (2 seconds?), tossing a couple of 10" chutes in the process? With Carl's DECAP motors, you could trim the delay on two of them down to a bare minimum to allow for the staging using 0-delay boosters.

Pyro Pro

01-13-2008, 12:06 AM

Impressive!

Concerning those launch lugs, did you try using two on just the booster?

This might be an interesting project for a micro electronics ignition system. A booster with 4xC casings in a tumble is still going to have a lot of inertia when it hits. Probably enough to knock off a fin or two. I think even a small 12" plastic chute might be useful to prevent landing damage.

Wonder how it might work if you connected just two of the motor tubes to the sustainer, and used the other two to eject the transition shroud section a few seconds later (2 seconds?), tossing a couple of 10" chutes in the process? With Carl's DECAP motors, you could trim the delay on two of them down to a bare minimum to allow for the staging using 0-delay boosters.

I wanted to keep at least one launch lug on the sustainer, in case a single-staged flight was desired, and I wanted to allow it to still be functional when used with the booster, because for some reason I just don't like having wasted launch lugs in a particular configuration (though, 2 3/16ths lugs on the booster and then 1 or 2 1/8" lugs on the sustainer, all mounted directly on the tube, would ensure adequate guidence on both clustered and single staged flight, so that would probably be the best option.

As far as the active recovery device goes, what if I did something like this:
(need to go RockSim this to get a good 3D model, but this might just work...)

barone

01-13-2008, 12:09 AM

This is what I'm thinking of, if it helps:

(and thanks, Ltvscout)
I just don't know about that. With no direct (straight) shot from the boosters to the sustainers, I don't think you'll get very reliable upper stage ignition. Has anyone ever tried this?

Mark II

01-13-2008, 12:19 AM

The Tetraphelion

A nice, fast, somewhat high-performance clustered, two-stage model with a payload.

...

I'm thinking that some sort of cone-type structure (with a base at the forward end of the motor mount, with an O.D. of 2", tapering up towards the ST-10 tube at the top of the booster) within the booster should be used (made of aluminum foil/Nomex paper, or something else flame resistant) to duct the booster gasses through to the sustainer through the ST-10 tube, and also to get rid of any corners where black powder soot could build up inside the booster.
I would guess that putting an inverted funnel shape inside the transition would probably work. You might be able to get away with making one out of cardstock and then coating it with epoxy to make it burn-resistant. I like the look of the design; like Scott said, it resembles a clustered 2-stage Laser-X, and I'm a fan of clusters :D (and multi-stagers).

I would definitely build this one for my fleet, either as designed, or else as a single-staged version (like the Laser-X). I think that it would make a real neat kit (even scale it up to 24mm and make it an SLS kit?). :)

Regarding the LL stand-offs - would it be possible to route the launch rod inside the booster stage (between two motor tubes, and either reduce or eliminate the need of standoffs for the upper stage? Doing so might even eliminate the need for having a launch lug on the upper stage altogether. To facilitate staging in this scenario, you would just need to design an indentation into the funnel inside the transition, and have the launch rod routed through this indentation so that it would bypass the funnel without entering it (imagine a kitchen funnel with a dent or a crease in the side).

Mark

ADD: Whoa! It looks like Craig and Don got their comments in while I was editing mine - sorry for the redundancy!

Mark II

01-13-2008, 12:32 AM

This is what I'm thinking of, if it helps:

(and thanks, Ltvscout)
I was thinking of something similar, but I would suggest shortening the length of the single straight tube at the upper end of the funnel shape; IOW, move the conical part closer to the sutainer nozzle, or even eliminate the straight tube altogether and have the nozzle end of the sustainer motor plug right into the top of the conical part of the funnel.

Mark

Mark II

01-13-2008, 12:37 AM

I just don't know about that. With no direct (straight) shot from the boosters to the sustainers, I don't think you'll get very reliable upper stage ignition. Has anyone ever tried this?
Has anyone ever tried doing this in a two-stage Nike Hercules? The N-H might be a good analogue for this.

Mark

Pyro Pro

01-13-2008, 12:56 AM

I was thinking of something similar, but I would suggest shortening the length of the single straight tube at the upper end of the funnel shape; IOW, move the conical part closer to the sutainer nozzle, or even eliminate the straight tube altogether and have the nozzle end of the sustainer motor plug right into the top of the conical part of the funnel.

Mark

The idea of the bit of ST-10 is to provide a sturdy point of attachment for the stage coupler, since the tube can be centered at the top of the ST-20.

Here was my idea for active deployment:
The motor mount tubes should be made of 4" lengths of ST-7 instead of 3", allowing an HTC-7 to be put into the tops of them. Built and glued into the model would be a matching set of 4 more 4" ST-7's. So, the HTC's at the top of the motor tube fit together with the 4 ST's in the main booster tube. Two opposing tubes (these are the ones glued into the booster) will be open, and act just like the motor tubes did in my original design. The other two will have a BTC-7 at their forward end, with an eye bolt, short length of elastic, parachute tied about 6-8" up the elastic, which is then tied to a fairly long (12-18") piece of Kevlar that is attached to the motor block in the motor tube. There should also be some sort of solid barrier that seals up the tube well enough that a minimal amount of wadding would be needed. The entire motor mount assembly is friction fitted into the base of the booster, tight enough that it will not eject itself at staging. When the ejection charges of the 2 standard booster motors fire, they will pressurize the area in between themselves and the small solid block that seperates the long piece of kevlar from the parachute section. Since there is a good bit of Kevlar in this area, the motor mount assembly should be ejected from the rocket at a fairly good speed, enough so that when it reaches the end of the Kevlar line, the resulting jerk should be enough to pull the parachute out of the tube.

If none of that made sense, I have another picture :); much easier to explain that way.

Think that might work?

(Note, on the RockSim image, I did not put the centering rings on the glued-in tube set to save time, but there should be two there).

Mark II

01-13-2008, 04:52 AM

The idea of the bit of ST-10 is to provide a sturdy point of attachment for the stage coupler, since the tube can be centered at the top of the ST-20.
My idea was intended to reduce the number of times that the burning propellant particles would have to change direction on their way up to the nozzle of the sustainer motor.

Here was my idea for active deployment:
The motor mount tubes should be made of 4" lengths of ST-7 instead of 3", allowing an HTC-7 to be put into the tops of them. Built and glued into the model would be a matching set of 4 more 4" ST-7's. So, the HTC's at the top of the motor tube fit together with the 4 ST's in the main booster tube. Two opposing tubes (these are the ones glued into the booster) will be open, and act just like the motor tubes did in my original design. The other two will have a BTC-7 at their forward end, with an eye bolt, short length of elastic, parachute tied about 6-8" up the elastic, which is then tied to a fairly long (12-18") piece of Kevlar that is attached to the motor block in the motor tube. There should also be some sort of solid barrier that seals up the tube well enough that a minimal amount of wadding would be needed. The entire motor mount assembly is friction fitted into the base of the booster, tight enough that it will not eject itself at staging. When the ejection charges of the 2 standard booster motors fire, they will pressurize the area in between themselves and the small solid block that seperates the long piece of kevlar from the parachute section. Since there is a good bit of Kevlar in this area, the motor mount assembly should be ejected from the rocket at a fairly good speed, enough so that when it reaches the end of the Kevlar line, the resulting jerk should be enough to pull the parachute out of the tube.

If none of that made sense, I have another picture :); much easier to explain that way.

Think that might work?

(Note, on the RockSim image, I did not put the centering rings on the glued-in tube set to save time, but there should be two there).
That looks like a good idea; it would eliminate the need for electronic deployment.

Mark

Pyro Pro

01-13-2008, 12:52 PM

My idea was intended to reduce the number of times that the burning propellant particles would have to change direction on their way up to the nozzle of the sustainer motor.
Mark

I definitely see your point, I'm just trying to think of how I could sturdily mount the HTC-10 stage coupler at the top of the booster without a support tube. I'm sure there's a way, and you're right, that would give the burning propellant an easier route up towards the sustainer's nozzle.

Pyro Pro

01-13-2008, 04:37 PM

CPMcGraw

01-13-2008, 05:52 PM

...Here was my idea for active deployment:
The motor mount tubes should be made of 4" lengths of ST-7 instead of 3", allowing an HTC-7 to be put into the tops of them. Built and glued into the model would be a matching set of 4 more 4" ST-7's....[Big Snip]...The entire motor mount assembly is friction fitted into the base of the booster, tight enough that it will not eject itself at staging...the resulting jerk should be enough to pull the parachute out of the tube...Think that might work?...

Essentially a pair of rear-ejection deployments. Sounds workable. The one (negative) thing I can see happening here is one or both of the parachutes snagging inside the booster between the rings instead of sliding completely out.

A solution might be to have a 5" length of tube, with its ID the same as the motor tube's OD, that the motor tube assembly could slide into. This would also eliminate any thrust vectoring of a motor tube not aligning itself properly, as well as give the parachute a full-length sleeve to pull out from. The parachute needs to be rolled tight enough to slip loosely to the end of the upper tube without binding, too.

Addendum: And as I re-read the above snippit, I actually see the words "entire motor mount assembly is friction fit". My eyes are not what they never were...:D

If I understand this concept now:

1. Two motors now ignite the sustainer...
2. The remaining motors eject the motor mount assembly out the rear of the booster...
3. The mount is attached to the outer shell of the booster with a harness that also is the attach point for the parachute(s)...
4. The parachutes essentially fall out? Perhaps they need a "rip chord" of some sort to ensure they get positively pulled out when the motor mount assembly is ejected...

Mark II

01-13-2008, 06:49 PM

Think something like this might work (provided the cardstock, or whatever material the shrouds are made of, are strong enough? The coupler would be supported by both the external and internal shrouds, and there could even be a very short (.125 or so, not shown) piece of ST-10 glued 0.5" from the top of the coupler to ensure the external transition blended with the sustainer. A few centering rings keep things in the right place when putting it together.
That certainly looks good to me, and is essentially what I was envisioning. Totally Tubular lists Nomex paper in a range of weights (thicknesses) in its website; this might be something to use in the internal shroud, either by itself or glued on top of cardstock (laminated to the cardstock). It is a bit pricey, especially for the thicker sheets, but you probably wouldn't need to use much of it. Something to consider.

Mark

Pyro Pro

01-13-2008, 06:58 PM

If I understand this concept now:

1. Two motors now ignite the sustainer...
2. The remaining motors eject the motor mount assembly out the rear of the booster...
3. The mount is attached to the outer shell of the booster with a harness that also is the attach point for the parachute(s)...
4. The parachutes essentially fall out? Perhaps they need a "rip chord" of some sort to ensure they get positively pulled out when the motor mount assembly is ejected...

That's the idea. I was hoping that, given the small volume between the "parachute protection" bulkhead and the end of the motor at ejection (something in the realm of 3/4 of a cubic inch), the ejection charge should blow out the motor tube assembly at a fairly good speed, and if the parachute is packed well, shouldn't require much of anything to pull them out of their tubes. It would be nice to have some sort of more positive pulling system, but all I can really think of at the moment would be to minimize the length of the Kevlar cord so that the motor tube assembly would have just ejected from the tube and not slowed down much (maybe 2-3 inches of slack between it and the bulkhead when ready for launch). Another would be to increase the length of HTC-7 that is friction fitted into the upper tubes, maybe gluing only about 1/4" into the top of the motor tubes, thus increasing the effective length of the piston, = more time under pressure = higher ejection velocity.

Pyro Pro

01-13-2008, 07:14 PM

That certainly looks good to me, and is essentially what I was envisioning. Totally Tubular lists Nomex paper in a range of weights (thicknesses) in its website; this might be something to use in the internal shroud, either by itself or glued on top of cardstock (laminated to the cardstock). It is a bit pricey, especially for the thicker sheets, but you probably wouldn't need to use much of it. Something to consider.

Mark

Thanks for the information. It looks like a $5.00 sheet of 0.005" would work, and last for quite a while (a 0.68" -> 1.98" x 5" long shroud would have a large radius of 7.68" and a 46.41* central angle when layed out on paper, so roughly 18-20 should be able to fit on a sheet, at a cost of around $0.25 each.)

James Pierson

01-13-2008, 07:54 PM

Pyro Pro

01-13-2008, 08:54 PM

Looks Great David, an innovative and amazing design. I am also glad this thread is finally active again.

Have you thought of adding some otter side pods to carry some rear ejection parachutes? Kinda like the Gemeni D.C. has for safe recovery of the Booster Stage. Also I think that the Sustainer stage, with the launch lug on one side only may track off to that side in flight. What do you think, I am just guessing on that?

James Pierson
NAR# 77907

The side pods did cross my mind, and they'd be a very reliable alternative if this current setup doesn't go smoothly (need to build this sometime...). As far as launch lugs go, I went ahead and took CPMcGraw's advice on them, using (2) 2" x 3/16" lugs on the booster for cluster flight, and having a single 1.75" x 1/8" on the sustainer for single-staged lower-powered flights. Attached is a RockSim file consolidating most of these new ideas:

Mark II

01-13-2008, 09:40 PM

The side pods did cross my mind, and they'd be a very reliable alternative if this current setup doesn't go smoothly (need to build this sometime...). As far as launch lugs go, I went ahead and took CPMcGraw's advice on them, using (2) 2" x 3/16" lugs on the booster for cluster flight, and having a single 1.75" x 1/8" on the sustainer for single-staged lower-powered flights. Attached is a RockSim file consolidating most of these new ideas:
The design looks much more refined and much more thought-out ;) :D now, especially with the removal of the launch lug stand-offs and the change to dual parachute recovery for the booster. I said before that I could readily see myself building this one right away; I'm even more eager to do so now. :)

Needless to say, this would definitely grab my interest if I saw some manufacturer offering it as a kit :D assuming that the other remaining details are worked out. Not that I'm trying to send any hints or anything.

Mark

James Pierson

01-13-2008, 10:15 PM

Pyro Pro Quote:
(need to build this sometime...).

Key Word here...........sometime. :D ;) .

This word "sometime" strikes a famillar cord with me as well. Once I think I have finally perfected a design it will soon change as another idea pops up :eek: . Must be "Rocket Evolutionary Chain" or something.

James Pierson
NAR# 77907

Pyro Pro

01-17-2008, 04:50 PM

No, I haven't built my design yet, but I think this is a pretty cool way to post screenshots of complex designs. Using the stereo-3D method of picture viewing, by having two images that are taken from slightly different locations, when your eyes are crossed the images are superimposed onto one another, giving the illusion that you are looking at a single 3D object. This in mind, I made a couple of sample images using 3D exports from RockSim (take a screenshot, pan the camera over, take another, paste them next to each other, crop and shrink as neccesary). The first is a closeup of the transition area of an Aerobee 350, and the second is a see-through image of the Tetraphelion's booster. It's a little strange explaining how to view them, but the idea is that you relax your eyes until what your eye is seeing seperates into your left and right eye's individual images. Then, you just have to focus and control the amount of relaxation until the right images are on top of each other. To make it easier (maybe?) I put a colored dot on each half, lining up the dots on top of each other will produce the effect.

I thought this might be a good idea to use, especially with complex designs, as it really helps bring all the parts and locations into perspective.

(Be advised, however, it can make your eyes a bit sore if you keep it up for too long, a few seconds at a time is usually fine)

(And one other thing is that the effect is, to me at least, much more realistic if you are about 2 feet away from your moniter, otherwise the pixelation can disrupt the image)

Mark II

01-18-2008, 02:41 AM

Rocket Doctor

01-31-2008, 12:47 PM

I have quite a few prototypes that Estes rejected or were not interested in and they didn't see the light of day at any new product meetings.

I designed a mini engine two stage rocket at their request, but, since they didn't want to produce mini motor boosters, that was a waste of my time.

I also made a companion to the mini two stage, using regular motors.

Just got back a box of about 13 prototypes besides the ones that I have already, quite a few.

Once again, estes needs competition on designs to go up against them.

For 2007, they were supposed to come out with three kits per month, and, I sat there in marketing when that "order" was announced by Barry. Did Estes come out with that amount, NO. They barely came out with anything close to that.

There marketing manager was fired and their VP of sales and marketing left, lots of turmoil out there.

Pyro Pro

01-31-2008, 05:22 PM

David,

I made a couple of small revisions in your RocSim file, mainly by specifying Semroc components where you hadn't done so (such as the nose cone) and making some corrections in other component specs (you specified some 4" long ST-7 tubes as ST-730, when they should be ST-740). I also ran a bunch of simulations. It looks like the Tetraphelion would do nicely on a combination of 2 Aerotech D21-4's and 2 Estes C6-0's in the booster, and an Estes B6-6 in the sustainer. It would hit about 3000 ft. with that setup. :) (This assumes, of course, that you can synch the ignition of the D21's with the C6's, but that wouldn't be a problem, right? ;) ) According to the simulations that I ran, it looks like you would need a little more oomph in the booster stage than you could get with an all-BP setup. (Watch the flight profile animations to see what I mean.) An all-Estes C6 setup in the booster will work (and get you to 2200 ft.) but you will still get a slight tip over just before the sustainer lights. What do you think?

(I had to Zip the RockSim file because it was just a little too big to upload otherwise.)

Mark

Thanks, I finally got a chance to go look this one over (been meaning to for a while). I hadn't thought of putting composite motors in the deployment tubes, but that would make for an impressive flight (if they all lit :)). I think that the tip-over you saw was due to the ejection delays that you put on two of the C6 in the simulation. While it is true that this is how the rocket would be flown in actuality, it has to be changed a bit for use in RockSim. RockSim doesn't light the upper stage motor until the delay on the longest burning booster motor has burned all the way through, so there was an additional 3 seconds worth of coasting after booster burnout (from those two C6-3's) and before sustainer ignition, which would explain the progressive tip over as the rocket coasted. I reran the simulation with 4x C6-0's and a C6-7 in the upper stage, then put an ejection delay on the booster parachutes (using the Flight Events window) of 3 seconds after stage separation to simulate the remaining delay time left on the 2 C6's, and the simulation looked better, with the sustainer lighting immediately after booster motor burnout, and recovery devices for the booster deploy a few seconds later.

Something else I noticed, and I might contact Apogee about this, is that when looking at the Deployment velocity category of your already-run simulations, the velocity is apparently a reading of the FIRST recovery device deployment. (I found this out when using a 0 second delay on the booster motors and got a Dv of around 400 feet per second, even though the graph showed that the rocket was traveling around 30 fps at sustainer deployment. When I put the 3 second deployment delay on the booster, it dropped down to 90, confirming this problem).

Thanks for updating the file, and I thought I'd post a few screenshots of the new design if anyone doesn't have RockSim and hasn't seen it since its creation.

Mark II

01-31-2008, 08:16 PM

Thanks, I finally got a chance to go look this one over (been meaning to for a while). I hadn't thought of putting composite motors in the deployment tubes, but that would make for an impressive flight (if they all lit :)).
Wouldn't it, though!! But admittedly, that's a mighty big "If". :rolleyes:

I think that the tip-over you saw was due to the ejection delays that you put on two of the C6 in the simulation. While it is true that this is how the rocket would be flown in actuality, it has to be changed a bit for use in RockSim. RockSim doesn't light the upper stage motor until the delay on the longest burning booster motor has burned all the way through, so there was an additional 3 seconds worth of coasting after booster burnout (from those two C6-3's) and before sustainer ignition, which would explain the progressive tip over as the rocket coasted. I reran the simulation with 4x C6-0's and a C6-7 in the upper stage, then put an ejection delay on the booster parachutes (using the Flight Events window) of 3 seconds after stage separation to simulate the remaining delay time left on the 2 C6's, and the simulation looked better, with the sustainer lighting immediately after booster motor burnout, and recovery devices for the booster deploy a few seconds later.
That's a relief. I was hoping that someone would be able to explain to me that what I saw was just an artifact of RockSim. It just didn't make sense to me, but because I'm still a relatively new user of the program, I couldn't pick out what might be wrong with the sim (let alone how to correct for it).

Something else I noticed, and I might contact Apogee about this, is that when looking at the Deployment velocity category of your already-run simulations, the velocity is apparently a reading of the FIRST recovery device deployment. (I found this out when using a 0 second delay on the booster motors and got a Dv of around 400 feet per second, even though the graph showed that the rocket was traveling around 30 fps at sustainer deployment. When I put the 3 second deployment delay on the booster, it dropped down to 90, confirming this problem).
I'm sure that Tim from Apogee would be the first one to point out that RockSim, for all its obvious strengths, is still a work in progress.

Thanks for updating the file, and I thought I'd post a few screenshots of the new design if anyone doesn't have RockSim and hasn't seen it since its creation.
I really like the see-through view. At first I was mystified about how you achieved that, until I realized that you must have temporarily changed the relevant body tubes to clear plastic in order to generate the graphic. I'll have to try that with some of my designs!

Mark

Pyro Pro

01-31-2008, 09:04 PM

I really like the see-through view. At first I was mystified about how you achieved that, until I realized that you must have temporarily changed the relevant body tubes to clear plastic in order to generate the graphic. I'll have to try that with some of my designs!

The ability to do see-through textures really is a nice tool. It's actually not the material that is changed, but the color. Basically, when you bring up a menu for editing a part, you've got tabs for General--Database--Mass Override--Color--Texture. When you bring up the color sub-menu, you have options like 2D color, boxes for choosing the color, and other things like that. At the bottom right of this menu, right above the 2D preview, there is a slider to change the opacity, and this is how you make the translucent 3D images. I think most parts are "1" by default, which is completely opaque. Just the same, "0" gives an invisible part. For my images I used 0.250 to make them mostly clear, but still retain a shadow of the part they represent. You can use personal preference on that part and figure out what works best to you. To toggle between a see-through and non-see through image, the toolbar just above the 3D rendering screen on the main RockSim page contains a button that looks like a red sphere with a chunk sliced out of it. If you click it, a check mark will toggle in its image. If it is checked, the opacity value is activated and applied to your 3D model, giving you a clear/translucent model. If it is unchecked, all parts are rendered opaque.

Here's an image with all the key parts highlighted, hopefully this helps:

Pyro Pro

02-01-2008, 06:22 PM

Well, here's what I picked up today after school :D

No idea when I'll find the time to build this, but it's all here when I do.

If I do happen to find the time, I'd like to get this done by this month's Bayboro launch to test it out. I'm thinking a first flight of 2x C6-0's in the booster ignition tubes, 2x A8-5's in the deployment tubes (gives a booster deployment 3.87 seconds after separation, which might be a little much, but at least rear deployment shouldn't be as bad, plus, it lets me use up a whole pack of A8-5's, instead of having to buy a separate pack of A8-3's, since the sustainer really needs the 5 second delay (more like a 6 second, actually).

I might get a chance to start working on it next Saturday (the 9th) night and Sunday, as I've got a lot of things to do for Science Olympiad, but the competition is on the 9th, so it'll all be done by then (or else!).

Carl@Semroc

02-01-2008, 07:20 PM

Well, here's what I picked up today after school :D

David,

Don't yell them you stopped by to pick it up after school, or EVERYBODY will be stopping off after school/work. :eek:

Pyro Pro

02-01-2008, 07:39 PM

Right... :D

This is what I looked at when I got home from school :)

Mark II

02-01-2008, 07:41 PM

Well, here's what I picked up today after school :D

I'm thinking a first flight of 2x C6-0's in the booster ignition tubes, 2x A8-5's in the deployment tubes (gives a booster deployment 3.87 seconds after separation, which might be a little much, but at least rear deployment shouldn't be as bad, plus, it lets me use up a whole pack of A8-5's, instead of having to buy a separate pack of A8-3's, since the sustainer really needs the 5 second delay (more like a 6 second, actually).
Are you sure that you'll have enough altitude at staging with that combo to let the booster fall for 4 secs. before it deploys the chutes? Maybe zippering won't be a problem, but what about the possibility of the booster experiencing an abrupt cessation of flight if the Earth were to intersect its descent trajectory somewhere within your projected ejection delay? :eek:

Mark

CPMcGraw

02-01-2008, 08:09 PM

Well, here's what I picked up today after school :D...

Whimper...

Sniff...

Such a beautiful picture... All nice and pretty, laid out as if it were a SEMROC kit... Brings back memories of when I last had the time to work on something...:(

I gotta pick out a project to build, now. I'm suffering with-drawl symptoms (I can do that: I'm a Southerner!). :eek:

Pyro Pro

02-01-2008, 09:51 PM

Are you sure that you'll have enough altitude at staging with that combo to let the booster fall for 4 secs. before it deploys the chutes? Maybe zippering won't be a problem, but what about the possibility of the booster experiencing an abrupt cessation of flight if the Earth were to intersect its descent trajectory somewhere within your projected ejection delay? :eek:

Mark

I did think about that, and though RockSim shows the booster coasting up from 296 feet up to about 700something, staging is usually a bit violent from the booster's side, so I went through a few little math things, assuming I'm remembering them right, though I probably am not. I think the height of a dropped object on earth over time is equal to -16t^2 (though, correct me if I'm wrong). I plugged it into my calculator, and assuming that the model stages at 296 feet, the booster immediately stops in the air with no coasting whatsoever, and that the launch is conducted in a vacuum, then it would take the booster 4.301 seconds to fall to the ground, where it would impact at 137.6 ft/s. Now, the ejection delay on the A8-5 would actually be more like 3.87 seconds, since the C6 burns for 1.13 seconds longer and staging wouldn't occur until the A8 is already 1.13 seconds into its delay burn, but I think you're right, I'm not sure I want to risk it falling even halfway down to the ground before deployment. I think I'll just go with the A8-3's in the booster :).

Whimper...

Sniff...

Such a beautiful picture... All nice and pretty, laid out as if it were a SEMROC kit... Brings back memories of when I last had the time to work on something...

I gotta pick out a project to build, now. I'm suffering with-drawl symptoms (I can do that: I'm a Southerner!).

Just because I got it all doesn't mean I can work on it :D. In fact, I think the last rocket that I completely finished, paint and all was... :eek: my Mars Lander, I think... that was nearly two years ago! Of course, I've built about 10-12 rockets since then, but they're all either half-finished, or in need of paint (unless you count my rocket glider and helicopter from last NARAM, which don't get any paint).

barone

02-01-2008, 10:07 PM

....... Of course, I've built about 10-12 rockets since then, but they're all either half-finished, or in need of paint (unless you count my rocket glider and helicopter from last NARAM, which don't get any paint).
They may not have got any paint but you did take a marker to them, didn't you? They be complete. Still got them? Lost my glider and my helicopter was a big old honker :rolleyes:

Pyro Pro

02-01-2008, 11:31 PM

They may not have got any paint but you did take a marker to them, didn't you? They be complete. Still got them? Lost my glider and my helicopter was a big old honker :rolleyes:

Yep, still have them both, in all of their red and black Sharpie colorfulness. Flew the glider a couple of months ago (November, I think) at a Bayboro launch on a B6. Didn't time the flight, but it was at least a minute, possibly a bit more. I still need to make a piston to fly my helicopter (built an improvised floating head one in the hotel room the night before the competition; it served its purpose and nothing more, falling apart on the way home :D), since there's no room for launch lugs and it relies on guide rods at the top of the piston to hold it in place until it reaches safe flight speed.

Soon it'll be time to make some new ones for NARAM 50... (along with all the other events)

barone

02-02-2008, 08:03 AM

Yep, still have them both, in all of their red and black Sharpie colorfulness. Flew the glider a couple of months ago (November, I think) at a Bayboro launch on a B6. Didn't time the flight, but it was at least a minute, possibly a bit more. I still need to make a piston to fly my helicopter (built an improvised floating head one in the hotel room the night before the competition; it served its purpose and nothing more, falling apart on the way home :D), since there's no room for launch lugs and it relies on guide rods at the top of the piston to hold it in place until it reaches safe flight speed.

Soon it'll be time to make some new ones for NARAM 50... (along with all the other events)
My glider thermaled off at NARAM (best glider I had :( ) but lost site after about 2 min and some odd seconds. Helicopter was a honker though. Usually get about 80 second flights with an A8-3. Good qualifier and guarranteed return.

So, do you drive your piston into the ground or fly off a pad? I usually fly off a pad. I glue launch lugs at the top and bottom of the piston tube for rod guidance. The rocket is usually friction fitted well enough that as long as the piston tube is guided, the rocket will be too. Ever piston launch a glider? Real bugger. Sometimes that momentary pause right before the rocket pops is enough to send the glider free from the pod (DQ - sep under boost). Hey, maybe we need a competition thread and hope it doesn't start sounding like CROC :rolleyes: .

Pyro Pro

02-02-2008, 01:12 PM

My glider thermaled off at NARAM (best glider I had :( ) but lost site after about 2 min and some odd seconds. Helicopter was a honker though. Usually get about 80 second flights with an A8-3. Good qualifier and guarranteed return.

So, do you drive your piston into the ground or fly off a pad? I usually fly off a pad. I glue launch lugs at the top and bottom of the piston tube for rod guidance. The rocket is usually friction fitted well enough that as long as the piston tube is guided, the rocket will be too. Ever piston launch a glider? Real bugger. Sometimes that momentary pause right before the rocket pops is enough to send the glider free from the pod (DQ - sep under boost). Hey, maybe we need a competition thread and hope it doesn't start sounding like CROC :rolleyes: .

Built a small wooden base that the piston rod slid inside. Might try the launch lug idea later...

Pyro Pro

02-02-2008, 09:02 PM

Went ahead and mocked up the transitions and internal shroud to see how they look pieced together:

Mark II

02-03-2008, 02:48 AM

I did think about that, and though RockSim shows the booster coasting up from 296 feet up to about 700something, staging is usually a bit violent from the booster's side, so I went through a few little math things, assuming I'm remembering them right, though I probably am not. I think the height of a dropped object on earth over time is equal to -16t^2 (though, correct me if I'm wrong). I plugged it into my calculator, and assuming that the model stages at 296 feet, the booster immediately stops in the air with no coasting whatsoever, and that the launch is conducted in a vacuum, then it would take the booster 4.301 seconds to fall to the ground, where it would impact at 137.6 ft/s. Now, the ejection delay on the A8-5 would actually be more like 3.87 seconds, since the C6 burns for 1.13 seconds longer and staging wouldn't occur until the A8 is already 1.13 seconds into its delay burn, but I think you're right, I'm not sure I want to risk it falling even halfway down to the ground before deployment. I think I'll just go with the A8-3's in the booster :).
Exactly the same analytical process that I followed... :rolleyes::D;)

Mark

James Pierson

02-13-2008, 10:35 PM

Well, this is was I have been pondering on for the past few weeks. Baically is an 36" version of the Tranquility series. Just calling it Tranquility 9 for now. It would be like building an Defender Space Probe with alot of added wieght and parts :D .

My main concerns are the wiegh of this design which is 9.6985 oz. unloaded and with 3-C6-5 wieghs in at 11.8873 oz. :eek:. Rocsim says that Estes motors all have bad lift off speeds, however the Quest B6 and C6 speeds are good for a 48" rod. Also, of course, many Semroc motors work great however Carl is working on these as we know.

Does anyone have first hand knowledge of the Quest motors and how accurate are they simmulated in Rocksim? I seem to need the little extra kick off the pad for this design. Any other motor suggestion would be helpful. Also if you see any improvements that could be made please jump in. I am not so sure about the upper paper transition stoutness :confused: .

Enjoy and Thanks in Advance, JP.

James Pierson
NAR# 77907

Mark II

02-13-2008, 11:22 PM

Does anyone have first hand knowledge of the Quest motors and how accurate are they simmulated in Rocksim? I seem to need the little extra kick off the pad for this design.
Hmm... [muttering]... ...Quest... ...motors... ...18... ...millimeter... ...D's... ...Hmmmmm... ...[muttering]... ... !! ...[expletive deleted]... :(

Mark

CPMcGraw

02-14-2008, 07:20 AM

Well, this is was I have been pondering on for the past few weeks. Baically is an 36" version of the Tranquility series. Just calling it Tranquility 9 for now. It would be like building an Defender Space Probe with alot of added wieght and parts...[snip]...

James,

Have you tried running this one with RMS motors? The 18mm D13 and D24 are in that family...

Addendum: I just tried to run this simulation, but I didn't see these motors in my RockSim files. Does anyone have them already, or do these need to be created?

Pyro Pro

02-17-2008, 07:51 PM

Well, this is was I have been pondering on for the past few weeks. Baically is an 36" version of the Tranquility series. Just calling it Tranquility 9 for now. It would be like building an Defender Space Probe with alot of added wieght and parts :D .
NAR# 77907

Wow! That's a cool design, it's like a mega-Defender/1B hybrid :D.

An update of sorts on the Tetraphelion; the centering rings have been cut (took a while to get the technique right for cutting them without tearing them to pieces). I also sanded down one end of each of the HTC's where they friction-fit with the deployment/gas-flow tubes (the new ones are a lot tighter than they used to be). Next up will be cutting out the fins. Another problem I had seen when doing the initial revisions to the design, but have yet to come up with a good solution to, is the gap between the bottom of the booster tube and the bottom of the deployment tubes. When readying the rocket for flight, the parachutes must somehow be loaded into these tubes, then all the Kevlar cord be inserted, and the motor mount assembly slid inside the rocket for flight. I'm trying to come up with a way to make sure all the cord stays where it needs to be once the motor mount assembly is put in, as opposed to it bunching up and preventing the motor mount from going in as far as it needs to go by blocking the tube couplers. I'll be working on this tonight a bit, but if anyone has a clever solution that I can't see, please let me know!

Mark II

02-18-2008, 04:29 AM

When readying the rocket for flight, the parachutes must somehow be loaded into these tubes, then all the Kevlar cord be inserted, and the motor mount assembly slid inside the rocket for flight. I'm trying to come up with a way to make sure all the cord stays where it needs to be once the motor mount assembly is put in, as opposed to it bunching up and preventing the motor mount from going in as far as it needs to go by blocking the tube couplers. I'll be working on this tonight a bit, but if anyone has a clever solution that I can't see, please let me know!
One thing to keep in mind is that you probably shouldn't have too much line between the motor and the balsa plug. When the motor is ejected it will begin to lose speed and momentum the instant that it gets all of the way out of the deployment tube because the ejection gas pressure will be relieved and the motor tube will begin to encounter wake turbulence and air drag. It will still need to have a lot of speed when it reaches the end of the Kevlar line, though, so that it can pull the plug and the parachute all the way out of the tube. Therefore, I think that you should have the Kevlar lines be only long enough to let the two motor tubes get just beyond the ends of the deployment tubes in order to insure that they retain enough force to pull out the recovery system. If you design them like that, then you will not have all that much line to pack in ahead of the motor mounts; you can probably just get the lines to fit into the couplers at the top of each motor tube as you are pushing the tubes in.

OK, here's what you can do: leave the two motor tubes empty until you have packed in the chutes. First insert the shock line for each chute, followed by the chute itself, and then the balsa plug. Push everything forward as far as you can with the empty motor tube, and then insert a dowel through the motor tube to push the recovery system and the plug in the rest of the way. Then pull the motor tube either part of the way or most of the way back out and insert the motor. Push the motor tube back in, allowing the short length of Kevlar line to accumulate in the coupler in the front of the motor tube. You won't be dealing with that much line, so you shouldn't have any trouble with it bunching up and blocking the tube.

You only need to have that line be just long enough to let the motor mount completely exit the tube and get perhaps two or three inches further out before the line goes taut and pulls out the recovery system. If you have it any longer than that, you run the risk of having the mount lose so much momentum that it can't pull the chute all the way out. And one more thing should be included in the design: if you haven't done so already, you should punch a couple of holes (or provide some other form of pressure relief) in the deployment tubes in the sections above where the balsa plugs will be seated, so that as the plugs start to get pulled out, they don't create a vacuum behind themselves. Another way to provide this vacuum relief might be to perforate the bulkheads at the upper ends of the tubes.

Do these ideas make sense?

Mark

Pyro Pro

02-18-2008, 12:18 PM

Mark II

02-18-2008, 01:47 PM

That does make sense, and it gave me another idea (sort of an add-on to yours). If there was a wire tool with 2 hooks on it, long enough to extend all the way through the motor tubes (at least 4.5" long), then the parachutes could be loaded ahead of time as per your method, leaving only the Kevlar cord to pack. Then, these two hooks could inserted through the motor tubes, hooked around the Kevlar, then be used to keep tension (but not too much tension) on the Kevlar as the motor tubes are inserted. Once the motor mount is in, a dowel or similar could push any Kevlar in the motor-containing part of the motor tube back past the thrust ring, then the motors could be installed for flight.
That's the right idea, but I'm not sure that your loading sequence (and the use of the tool) doesn't make things more complicated than they need to be. I do think that your method would work just fine, but I also think that there is an easier way. I'm not as skilled with an illustration program as you are, so I'll have to rely on a verbal description:

1) Pull the booster motor tubes and recovery system all the way out of the tubes (fully extend the shock cord).

2) Fold and prepare the parachutes as you normally would.

3) Begin inserting everything back into the tubes, starting with the loose shock cord and the parachute. Just stuff it in. Then insert the balsa plugs.

4) Insert the empty motor tubes next (stuff in the Kevlar leashes just ahead of them) and use them to push the shock cords, parachutes, and balsa plugs in as far as you can without losing hold of the motor tubes.

5) Pull the motor tubes most of the way, but not all of the way, back out.

6) Insert a dowel into each empty motor tube and use it to push the recovery system the rest of the way in.

7) Leaving the motor tubes about 3/4 hanging out of each deploy tube, install the motors into each mount.

8) Push the mounts into the deploy tubes. As you push in the mounts, they will push the Kevlar leashes in ahead of themselves. The leashes will just bunch up ahead of the motors, but there won't be enough leash in each tube to cause any problems with inserting the motor tubes. There should be plenty of room ahead of the fully inserted motor tubes for the leashes to just bunch up without impinging on anything.

Mark

Pyro Pro

02-20-2008, 06:28 PM

Ok, now I think I understand your way more... it should work. The hooks I had in mind were just a bit of added reassurance that the Kevlar wouldn't get pinched inside the coupler, but if the tube is put in right they probably wouldn't be needed.

I got the fins cut out last night, now it's time to put it all together! Hopefully I can have it done by Saturday :)

Mark II

03-23-2008, 08:48 PM

I don't know how well known this is... but, while I was perusing back issues of Apogee's Peak of Flight newsletter, I found a little tidbit about enhancing the 3-D in the 3-D view in RockSim. It seems that if you view a design in 3-D view, and are wearing 3-D glasses (red lens on the left, blue lens on the right), and then type in the number 3 on your keyboard, the image actually becomes a real 3-D image (as in, seeming to pop out of the screen). It's no joke; I just tried it, and it worked! It really helps to have the various rocket components in the desin be individually colored, especially the exterior, and not displayed in the default (fast-view) over all blue.

Take a design that has a colored view, like the Tetraphelion, and click on the 3-D button. Press 3 on the main keyboard or on the keypad; I'm not sure which one works better, so try hitting the 3 in both places. Now swing the Tetraphelion into an oblique view, and then slowly magnify it using the camera controller. Click on the trackball button, and use your mouse to move the image around to view it from different angles (Hold down the mouse button and drag the pointer around.)

Hey, Pyro Pro! Your design now looks even cooler than before! :D

Now let me go back and take another look at the other designs posted in this thread... :cool: :cool: :cool:

Mark

Tau Zero

03-30-2008, 01:28 AM

Oddly enough, only the second one with a BC-760 that I've ever completed. :o

For those who may be interested:

http://www.oldrocketforum.com/showpost.php?p=37035&postcount=49

Cheers,

James Pierson

04-19-2008, 11:42 PM

These Images are for Carl and all at Semroc but I know they would want me to share them with the rest of you folks do here they are. Also a big THANK YOU ;) to Carl for the custom cut fins and custom centering ring. These incredible parts made this build sooooo much easier. So easy in fact that I got it built in about three hours :D .

The weather here stinks, in fact it snowed the past two days off and on so I havn't got much painting done and will postpone any test launches as well :( .

Enjoy and Thanks to Semroc!

James Pierson
NAR# 77907

http://i134.photobucket.com/albums/q104/rocketry_preservation_society/Tranquility9Image1.jpg

http://i134.photobucket.com/albums/q104/rocketry_preservation_society/Tranquility9Image2.jpg

http://i134.photobucket.com/albums/q104/rocketry_preservation_society/Tranquility9Image3.jpg

.

Carl@Semroc

04-19-2008, 11:46 PM

James,
That came out great! NOW I see how it all goes together. Thanks for the photos.

James Pierson

04-20-2008, 12:25 PM

Carl@Semroc
James,
That came out great! NOW I see how it all goes together. Thanks for the photos.

Thanks Carl, I just hope it flies as well as it went together. It's actual build wieght is about 1/2 0z. heavier than Rocksim says without paint and CG is about 1.5 inchs aft. The first flight is I plan on using 3- C6-3 instead of C6-5 as Rocksim says. Should be an exciting test launch :D . Pictures & Video pending launch.

PS. Also have a 1/4 ich stainless steel launch rod that is 6 foot long to launch with. Just trying to avoid that worm seeking missile transformation :eek: .

James Pierson
NAR# 77907

James Pierson

05-11-2008, 10:26 PM

Paint and launch of Tranquility 9 finally complete.

http://i134.photobucket.com/albums/q104/rocketry_preservation_society/Tranquility1and9.jpg

OPROC Launch May 10th 2008 at Discovery Bay launchsite: Tranquility 9 being flown on 3-C6-3 for it's first Test Flight :eek: . We used an 1/4 inch Stainless Steel launch rod that was 6 foot long. I just wasn't sure about the launch speed for stability. I would appreciate all input and might just go to an maxi rod of 3/16 inch and 48 inches long. Also might just try this design next time on 3-B6-2 for a lower pod ejection??? Your input Please.

PS. I am new a posting this video stuff so I see one problem and need help. Can the general public view all my photo's on photobucket or is there a way to keep them locked and private???

http://i134.photobucket.com/albums/q104/rocketry_preservation_society/th_Tranquility9Launch.jpg (http://s134.photobucket.com/albums/q104/rocketry_preservation_society/?action=view&current=Tranquility9Launch.flv)

James Pierson
NAR# 77907

CPMcGraw

05-11-2008, 11:24 PM

James,

The (3) C6-3s looked OK as far as altitude, not more than 350' from the camera angle. Anything below this power probably wouldn't feel right (or safe).

What was that dark mass the camera kept looking at after deployment? A clump of wadding, or the upper part of the model?

PhotoBucket and privacy, what a concept... :o No answer there, James. For stuff like this, I wouldn't worry about it that much. Most folks would just look at it and say we're a bunch of geeks with too much time on our hands; they probably wouldn't look at the model and say "OOH, there's a hot design we can pirate!" :D

Great flight, BTW! :cool:

James Pierson

05-11-2008, 11:45 PM

CPMcGraw
What was that dark mass the camera kept looking at after deployment? A clump of wadding, or the upper part of the model?

Dark Mass was the nose cone on a seperate chute. The lower main body had its own chute but the 1/4" shock cord (Singer Brand woven ) burnt off at the mount. Luckily no damage on impact to the lower body tube. I really need to start using the Kevlar :o .

James Pierson
NAR# 77907

Mark II

05-17-2008, 09:18 PM

Here is a re-creation (a Retro-Repro!) of a design that appeared in the May, 1970 Astronautics Modeler (http://www.ninfinger.org/%7Esven/rockets/catalogs/semroc570/570semroc4.html) by a little company that was called, I believe, Semroc Astronautics Corporation. The design appeared on pp. 5-6 of the publication, and was presented as a free complimentary rocket plan. It is a minimum diameter 3-stage rocket that flew on 18mm propulsion modules. I have reproduced the design in RockSim, substituting modern day Semroc parts for the parts listed in the plan. I did upgrade the shock cord system to use current techniques, and I also substituted a streamer for the original design's 12 inch parachute.

Length: 21.4 inches
Diameter: 0.759 inches
Span: 8.259 inches
Empty Weight (all stages): 1.08 oz.

Sustainer Length: 17.4 inches

I didn't have (or couldn't find) an engine file for the Semroc motors, so I simmed the Cyber III on Estes and Quest motors. The sustainer alone will do 984 ft. on an Estes B6-6, and will go to 1785 ft. on a C6-7. In full up 3 stage configuration, the Cyber III will go to almost 3300 ft. when it is loaded will all C's. :eek: (But seriously, who would ever do that?)

I have all the parts on order from Semroc, and I do plan on building this one. I'll also make sure to take plenty of pictures of it, so that I will have something to remember it by after I launch it.

Mark \\.

CPMcGraw

05-17-2008, 11:31 PM

Here is a re-creation (a Retro-Repro!) of a design that appeared in the May, 1970 Astronautics Modeler (http://www.ninfinger.org/~sven/rockets/catalogs/semroc570/570semroc4.html) by a little company that was called, I believe, Semroc Astronautics Corporation....

...In full up 3 stage configuration, the Cyber III will go to almost 3300 ft...

I just looked at the sim file, and spotted some naughties... :(

Your deployment velocities for full-house stacks are in the shredder range, and your guide rod requirements are well beyond 36". Some are approaching 60", which means your liftoff velocity is dangerously low. :eek:

This is the CORE REASON (pun intended) why we need those core-burner motors Carl is planning. :rolleyes: The regular end-burners just don't have the power to launch these stacks. Think Mars Lander here. The C5 was a much better motor than the C6...

It's also why we don't fly Farsides and T-Birds anymore (aside from not having fields large enough to recover them in), and why the Comanche III needs a D12 booster.

You might want to hold off trying to launch a full-house stack until we get some proper motors from Carl.

Mark II

05-18-2008, 03:55 AM

CPMcGraw

05-18-2008, 07:57 AM

Yes, I would have preferred to sim the model using Semroc's motors, but I couldn't find the file. Using a 4 or 5 ft. launch rod is a personal preference; in the past 5 years that I have been flying rockets, I have very rarely had the pleasure of launching into calm winds (less than a handful of times, in fact). A 4 or 5 foot rod is pretty much standard where I launch; it is also the rod length on my club's launch pads and towers. What length of launch rod do you use?

36" mostly. I do substitute a steel rod for the lightweight aluminum two-piece in all my pads (common Estes types). I have one 48" x 3/16" rod for larger birds. I fly in a schoolyard, so there's not a lot of room for drift. If the winds are steady or gusting above a certain limit, I don't fly.

Also, just exactly when does the deploy velocity of a streamer reach the point of shredding? This has always been a mystery to me in RockSim. When I look at the results table, I can tell when the dv's are way too high (in triple digits of ft./sec.) as well as when they are apparently safe (in the single digits for ft./sec.), but it is the transition point between safe and shred that I have never been able to figure out. Maybe I just haven't launched enough rockets yet either, but in real life I have never had a streamer or chute shred on me in anything that I have ever launched, and I mostly fly low power scratch-builds that I have never simmed. I don't doubt for a minute that it happens, but perhaps because I personally have never seen one, I just don't know when a streamer deployment would cross the line between OK and Not OK in real life either.

Anything above 20 FPS is in the "danger zone" (cue up the Top Gun theme music here) for parachutes; streamers should be able to take a little more, maybe up to 30 FPS, and still be safe. Some of your sim runs were in the high 50's, though, and that's pushing the construction envelope for crepe paper and safety tape streamers. If you can here an audible "POP" like a gunshot when a parachute opens, the Dv is excessively high. The best way to "guess" at the safety zone is simply to trim the power curve to reduce the Dv as much as possible for any model, parachute or streamer.

I am also in the dark about liftoff velocity when I am looking at the results table after performing a sim. Which column of numbers tells me that it is too low, the "Max velocity Feet/Sec" or the "Max acceleration Feet/sec/sec"? The only time that I ever see a liftoff speed that is too low in the Flight Profile animation is when the animation shows the rocket pranging after liftoff. And the only time I ever see that is when I try to sim a rocket using a motor that is obviously too small (a 1/2A in a Big Bertha, for example). If I don't see a prang, and the rocket continues on an essentially vertical course in the animation (something that is also affected by how much wind I have input into the Launch Conditions preference screen), then I interpret that to mean that the rocket had a safe liftoff. Where did you see that the liftoff velocities were too low?

Any LPR stack we come up with should reach flight V before it reaches 48", and most stacks should reach the same V before 36". This is what most of us will have with any standard Estes pad. I think RockSim is programmed with 49 FPS as the target V for safe flight. It has to do with the interaction of the airflow over the fins, and at what point there is enough resistance to rotational forces to keep the model on a straight path.

Again, I would LOVE to use the new motors that Carl is developing, but I don't have .eng or .rse files for them yet.

I whipped up a set of those files, but they're not completely accurate. They work in a pinch, but the motor curves are not tweaked to conform to any actual firing data (obviously). I thought they were posted somewhere here in the SVDT area.

Mark II

05-18-2008, 04:26 PM

A sincere thank you, Craig. You answered a whole boatload of questions for me. I think that I will be able to use RockSim a bit more intelligently now. :D

I do recall that you had created an engine file for the Semroc motors. I'll search back through the thread for it.

After I created the Cyber III file, I started running simulations using various motor combinations. Obviously, several of them didn't work, especially the first 7 or 8 sims I ran. I usually just leave the unsuccessful sims in my RockSim design files along with the successful ones as a personal log of what combinations I had tried. My Cyber III working file, with all the sims that I had run up to that point, was the one that I attached to my original post. My inclusion of all of my sims in the file was not meant to indicate that I thought they all worked, but I did hope to get some comments on the sims that did work and maybe some feedback on the ones that didn't work. (And as I indicated in my last post, I wasn't sure which sims really didn't work, but I had an idea, and which sims were kind of marginal but maybe could work under the right conditions. I really didn't know how to identify which ones were of that last type. I was hoping for some feedback about it, which you did provide.)

Anyway, here is a revised file with all of the sims that had obviously unworkable combinations removed. I also changed my launch rod length to 36", and reran all of the sims that are left from the file that was in my earlier post. I also ran a completely new sim using an "all up Estes C" combination (Sim #6), and got some surprisingly different results from my previous sim of that combo. (After your last post, I did do some looking around in RockSim and at last found out where to get the more complete sim results, which included the information that you had mentioned.) As you can see from the list, I repeatedly ran that same combination of motors while trying to tweak the delay to match what Rocksim indicated as the ideal delay. The combined results indicated that RockSim's estimate of the "ideal delay" was a moving target. Also, the program kept producing inconsistent results when using the same motors with the same delay. See especially Sim #7 and Sim #8. Also, it seemed odd to me that a few hundredths of a second of delay made so much difference in the dv when the rocket was at the point in its flight where its velocity had already slowed down quite dramatically and the rocket was moving pretty slowly or even, perhaps, was barely moving at all.

This reminded me of some sims that I had recently run using the design file provided by Apogee for the Cosmodrome Aerobee-Hi. In all the multistage configurations that I ran, the results kept showing quite high deployment velocities, even though recommended ideal delays were almost identical to the ones that I was using, and the profile animation showed safe recoveries. It caused me to wonder whether RockSim consistently overestimated the dv of the sustainer in multistage designs. I have also attached that file (compressed, because otherwise it was too large for YORF). Take a look especially at Sim #52, the last one on the list. The delay that I used was eighteen one-hundredths of a second (0.18) off of the recommended delay, and yet this difference resulted in a dv of over 467 ft./sec. :eek: The only way that the Aerobee-Hi would slow down from 467 ft./sec. to 0 ft./sec. in 0.18 seconds was if it hit a solid brick wall (at 2206 feet altitude!). And yet, the sim showed that it continued climbing for another 3838 feet after the streamer deployed (which was 0.18 seconds too early, according to the sim)! :eek: :eek: I am running the latest version update of RockSim 8 (version 8.2.2f4).

Mark \\.

CPMcGraw

05-18-2008, 06:47 PM

...It caused me to wonder whether RockSim consistently overestimated the dv of the sustainer in multistage designs...

It wouldn't be the first time RockSim dropped the ball on some calculations. I just ran into some really bizzare errors that affect one of my designs (Dominion Keeper). Bottom line, RockSim said it was very stable, but the model said otherwise in flight... :(

Now that I think about it, this makes two such errors! Kitfox was a bust in reality, while RockSim said it was fine...

So, don't accept anything RockSim says as written in stone. Mud, maybe, but not stone...

Pyro Pro

05-18-2008, 09:28 PM

In all the multistage configurations that I ran, the results kept showing quite high deployment velocities, even though recommended ideal delays were almost identical to the ones that I was using, and the profile animation showed safe recoveries. It caused me to wonder whether RockSim consistently overestimated the dv of the sustainer in multistage designs

I haven't looked at your file yet, but it sounds like the same problem I've had when simming some of my other designs. I think that RockSim gives the Dv of the booster instead of the sustainer, apparently just looking for whatever device deploys first. If you're using a 0-second delay as a booster motor, this could be giving you very high Dv values. Since you need a 0-second delay to get good stage ignition when simulating, try setting under the flight events window for the booster parachute/recovery device to be deployed at a specified time after stage separation, and see if this affects your Dv. Of course, if you want the sustainer Dv, you'll just have to temporarily delete the booster recovery device.

EDIT
Just looked at the Aerobee file, and that looks like what it was doing. You did set a 2 second delay for booster recovery device deployment, gave a much lower Dv than deployment at stage separation.

Mark II

05-21-2008, 12:15 AM

OK, consider this to be a work in progress. Attached is a RockSim file for my SLS Cyber III, a 176.55% upscale of the design that I posted the other day. I have had to play around with the fin material to get a rocket that will boost safely off a 48" long x 3/16" diameter rod. The sim log reflects a succession of trials with fins made from balsa, thin plywood and finally, 1/16" thick G-10 (which, I know, Semroc doesn't carry) in a variety of wind conditions. I also had to switch the body tube material from LT-125 to ST-13 to shave off more weight. If I can believe the velocity figures shown in RockSim's launch reports, launching the full-up 3-stage version seems to work a little better with lower impulse motors in the two upper stages, simply because they give it a lower GLOW. But doing so significantly lowers the max altitude. Using 3 stages to barely get to 1000 feet hardly seems like it is worth the effort.

A full-up configuration with 24 mm black powder motors in all 3 stages appears to be within the weight limit for the 1st stage D12 booster (with about 2 oz. to spare), though, so I'm not quite sure what the problem is.

I designed a modified version that has 18mm motor tubes in booster 2 and the sustainer, but that has its problems, too. Launching it in 2-stage configuration just doesn't seem to work, and it feels like it is almost criminal to launch the sustainer in single stage mode with just a C motor. In full-up mode, it barely scratches 1500 ft, which might actually be a blessing in disguise.

I put a rip-stop nylon streamer in the sustainer for recovery, to try to insure that it would recover somewhere within North America, but now I'm wondering if switching to a medium-sized parachute would actually save some weight. Anyway, I am interested in anyone's comments and suggestions. I rather like this old Astronautics Modeler free design, and would like to find more ways to optimize it for better performance.

Mark \\.

ADDENDUM: I had to delete some repetitive sims from the file to get it down to within YORF's limits.

CPMcGraw

05-21-2008, 05:33 AM

...If I can believe the velocity figures shown in RockSim's launch reports, launching the full-up 3-stage version seems to work a little better with lower impulse motors in the two upper stages, simply because they give it a lower GLOW. But doing so significantly lowers the max altitude. Using 3 stages to barely get to 1000 feet hardly seems like it is worth the effort...

GHS said basically the same thing in the chapter on staging. Your sim runs seem to be confirming his prediction that the top-end performance drops off of (almost any) stack once it reaches about three stages. At some point, it's not the mass of the entire model, but just the mass of the motors, that the first stage has to struggle to lift.

Mark II

05-21-2008, 02:49 PM

GHS said basically the same thing in the chapter on staging. Your sim runs seem to be confirming his prediction that the top-end performance drops off of (almost any) stack once it reaches about three stages. At some point, it's not the mass of the entire model, but just the mass of the motors, that the first stage has to struggle to lift.
Yeah, I need to start hitting the Handbook again. Mr. Short Attention Span here has only read little bits and pieces of The Handbook of Model Rocketry, but probably not enough to get a thorough grounding - apparently I know just enough to get myself into trouble. :D What you said about staging, though, reminds me of something that I read somewhere about the development of the Saturn moon rocket. Von Braun and his tream of designers had to add a fifth F-1 engine to the first stage partly because the first stage needed the extra thrust to enable it to lift its own load of fuel. (At least, I think I read that somewhere.) But it illustrates your point. I guess that with our own model rockets, optimal multistage performance is all about the Isp.

I haven't totally given up on the design yet, though - there's a few more tweaks that I want to try with both versions.

Mark \\.

Mark II

05-21-2008, 03:39 PM

OK, that's better. The Cyber III design that was included in the May, 1970 Astronautics Modeler called for 4 fins on each stage, for a total of 12 fins. Well, as it turns out, that number of fins adds quite a bit of drag. I don't know why I didn't see that before. So what I did was to drop one fin from each stage. The result: much better performance in all configurations. :D The new version no longer requires a long rod; it gets going safely off of a standard 36" launch rod. Even with B6-0's in both booster stages and a C6-7 in the sustainer, the revised 9-fin Cyber III gets some serious altitude. And in single stage configuration, it hits over 1000 feet on a B6. :eek: No ultralightweight G-10 fin material needed, either; this revised design uses stadard 3/32" balsa for the 9 fins. The attachments tell the story.

Now let me try the same thing with the SLS version...

Mark \\.

Mark II

05-21-2008, 04:25 PM

Not as much of an improvement in the SLS version, though. That D12 just doesn't have enough punch as a booster motor. Using 9 fins made from 1/8" balsa, it really only works with a D12-0, B6-0, A8-5 combination, off a 48" launch rod. Pretty much the same is true with fins made from 1/16" aircraft plywood, even though the fins are lighter. I still have to go with fiberglass fins to get acceptable performance with more than one combination of motors, and even then, it's not all that great. The GLOW with a full stack appears to be well within the D12's comfort zone, yet it struggles to get up enough speed off a 4 foot launch rod. These results just don't make sense to me.

Mark \\.

CPMcGraw

05-21-2008, 04:49 PM

...Cyber III design that was included in the May, 1970 Astronautics Modeler called for 4 fins on each stage, for a total of 12 fins. Well, as it turns out, that number of fins adds quite a bit of drag...what I did was to drop one fin from each stage. The result: much better performance in all configurations...

And this part of the story reminds me of what I've read about the development of the WAC Corporal...

Seems the "rocket experts" of the day didn't believe a three-fin rocket could fly correctly, and insisted the Corporal needed four. The designers simply applied the weight of history, in the form of a three-feather arrow, which always seemed to fly quite well, thank you...:D

Drag is a major component that can either be a hinderance (as in that 4-fin stack) or it can a helpful companion (a drogue chute on a hang glider).

CPMcGraw

05-21-2008, 05:36 PM

Not as much of an improvement in the SLS version, though. That D12 just doesn't have enough punch as a booster motor...

I just ran your 9-fin version with my SEMROC motor files, and here is an example of having a decent spike from a cored motor:

C5-0/B14-0/C6-7......3025'......Dv 15.9 FPS......31" x 1/8" rod
B14-0/C5-0/C6-7......3270'......Dv 14.4 FPS......44" x 3/16" rod

You should notice the discrepancy of 250' when using the B motor in the first booster, instead of the C motor. The B14 has nearly 3X the kick (23 Newtons vs 7.6 Newtons) of the C5. The B14 only burns for ~0.34 seconds, where the C5 burns for ~2 seconds. What the B14 does best is drop-kick the stack off the pad, probably staging almost as quickly as it reaches the end of the rod. The ~2 second burn of the C5 is a good sustainer for the second booster.

Mark II

05-21-2008, 06:03 PM

I just ran your 9-fin version with my SEMROC motor files, and here is an example of having a decent spike from a cored motor:

C5-0/B14-0/C6-7......3025'......Dv 15.9 FPS......31" x 1/8" rod
B14-0/C5-0/C6-7......3270'......Dv 14.4 FPS......44" x 3/16" rod

You should notice the discrepancy of 250' when using the B motor in the first booster, instead of the C motor. The B14 has nearly 3X the kick (23 Newtons vs 7.6 Newtons) of the C5. The B14 only burns for ~0.34 seconds, where the C5 burns for ~2 seconds. What the B14 does best is drop-kick the stack off the pad, probably staging almost as quickly as it reaches the end of the rod. The ~2 second burn of the C5 is a good sustainer for the second booster.
Thank you for running those sims. That was with the SLS design? If so, which fin version did you use (balsa, plywood or glass)?

I do remember the old Estes B14, even though I never got to try it. That B14 was the secret to getting the Farside and the Omega up and on their way, wasn't it? Yup, I do understand the importance of having the first booster deliver a big thrust spike to overcome inertia; it takes a lot of energy to get something moving from a standing start (especially if the direction is straight up). Once the thing is moving, it doesn't need quite as much power to keep it going. One of the most successful motor combinations for the SLS Cyber III involved putting a D12 in the first stage, a Quest B6 (which is a little bit more powerful than the Estes version) in the second stage, and an A8 in the sustainer. The lower mass of the upper two motors helps out more than their lower impulse hurts; once the stack is moving, it doesn't require all the power of a C or a D (or an E9 - you don't want to see what that combination did) to keep it moving upward and turning in a nice flight. I am so looking forward to seeing core-burning black powder motors like the B12 becoming available again, so that I finally get to fly some decent 3-stagers.

Mark \\.

Mark II

05-21-2008, 06:07 PM

One other variation that I thought of (and I may indeed try to sim it) involves adding two strap-on boosters loaded with A10's to the first stage. Now that I have gotten three fins out of the way, I might be able to make it work. I would call that version the Cyber IIIc. :D :D :D

Mark \\.

CPMcGraw

05-21-2008, 09:58 PM

Thank you for running those sims. That was with the SLS design? If so, which fin version did you use (balsa, plywood or glass)?

No, it was the one previous to the SLS posts. This is the ST-7 version with 9 fins instead of 12.

I do remember the old Estes B14, even though I never got to try it. That B14 was the secret to getting the Farside...up and on their way, wasn't it?

That and the Centuri T-Bird. Very large spike, very short burn. All-at-once grunt power.

You'll see the B14 especially used in nearly all of the larger 2-stage models of the '60s, like the Centuri Marauder and Long Tom, and the Estes Delta and Avenger. In fact, the Delta (used with the Camroc) recommended a B14-0/B14-6 and B14-0/B14-7 combination.

Pyro Pro

06-02-2008, 10:43 PM

Well, now that I'm out for the summer, I can actually get around to building some of these rockets! Reviewing my Tetraphelion design, I've decided to make a couple of changes, in that I am going to be converting the design from its original nasty rear-ejection-removable-motor-mount form, to rear-ejection using dummy strap-on boosters. The strap ons should make the rocket MUCH more user-friendly as far as flight prep goes, uses fewer parts, and should be more reliable. Using ST-7 strap-ons with the BC-726CN (http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=699) gives the design a kind of neat, space-launcher-like look, and the nozzle-half of the BC-726CN can be used just like a nose cone in a traditional model (though the shoulder is a tiny bit short, it shouldn't be a huge problem). Unfortunately, RockSim doesn't really allow for true strap-ons, but I did the best I could aesthetically with 2 offset inside tubes (I didn't go so far as to simulate the nose cone and nozzle, as this could only be done with many, many layers of tube couplers, engine blocks, or centering rings, but this gets the idea across). The simulation data in this case shouldn't be too accurate, since the tubes will add a lot of drag that isn't accounted for, but it should be somewhat similar to the original design.

snaquin

06-03-2008, 05:58 PM

Looks really interesting David .....

I like it!

.

Mark II

06-05-2008, 04:05 AM

Yesterday I finished building my first version of the Cyber III. I was conservative with this build and, for the most part, I strictly followed the published plan. This version has 12 fins (4 per stage) made from 3/32" balsa, and they are airfoiled as specified in the plan instructions. The empty weight (minus streamer) is right about 40 grams, or 1.14 oz. I made an obvious tweak in the RockSim file that I had previously overlooked - I aligned the sustainer fins with the first stage booster fins, instead of having the fins of all three stages set ay different angles in relation to each other, to reduce the drag somewhat. I didn't realize that I could do that until I stacked the three completed stages together!

Length: ...................21 in. ; 53.34 cm.
Weight: ...................1.14 oz. ; 40 gm. (without streamer)
Diameter: .................0.759 in. ; 19.28 mm.
Maximum Fin Span: ....8.26 in. ; 20.98 cm.

Qst B6-0/Qst B6-0/Est C6-7........ alt. 2570.12 ft.; 783.37 m......... v. 628 ft/sec......... accel. 966 ft/sec/sec.............. dv. 13.19 ft/sec.
Qst C6-0/Qst C6-0/Est C6-7........ alt. 3404.36 ft.; 1037.65 m........v. 641.2 ft/sec....... accel. 1038.36 ft/sec/sec........ dv. 16.05 ft/sec
Est A10-0T/Est A3-0T/Est B6-6.... alt. 1443.65 ft.; 440 m..............v. 444.37 ft/sec...... accel. 996.53 ft/sec/sec...........dv. 21.95 ft/sec

(Whew! I'm glad that I used epoxy to attach those fins!)

For the time being, I will be investing in some Quest B and C booster motors, and will be looking for calm days if I decide to fly it. ;) But I'll be waiting for the day when I can fly this baby the way it was really meant to be flown: on Semroc motors!!! :D

Mark \\.

snaquin

06-09-2008, 09:35 PM

Mark II

06-09-2008, 10:48 PM

Looks nice Mark ..... any idea what colors you will use to finish Cyber III?

.
I took a stab at that issue in the 3d view of the Rocksim file. But nothing is set in stone (or paint) yet. I took a cue from the grayscale illustration on the first page of the plan, and made each stage a different color. I'm still thinking of what elements I want to use on a decal or a set of decals, too.

Other than that model, I haven't built much lately. Instead, I have decided to struggle my way through the learning curve and (attempt) to paint the 40 rockets that I built last year. Painting the Cyber III is part of that initiative, too. ;)

I did start designing a Mega Cyber III (2.5x), but suspended it to concentrate on the SLS version. The Mega version will either have electronic ignition of composite motors in the upper stages, or will feature clusters of BP motors, or both. :D I can't help it, I just like the design. :p

Mark \\.

Mark II

06-25-2008, 09:57 PM

I have made a few modifications in this design, which have resulted in improved performance.

switched to 1/16" balsa for the fins for Booster #2 and the Sustainer
switched to 3/32" balsa for Booster #1's fins
changed the motor mounts in Booster #2 and the Sustainer to 18mm
Also, take a look at the fin orientation in the three stages. Because they do not overlap, the fins for the two boosters are in line. The sustainer's fins do overlap those of Booster #2, but I twisted the stage so that the sustainer fins are as close as possible to Booster #2's fins. I did this to try to minimize the drag as much as possible.

Launching off of a 60" rod (it needs at least a 48" rod), a combination of a D12-0, a C6-0 and an A8-5 will nicely lift the sustainer to 1225', even in 3-7 mph winds (with the launch rod angled 6.5° with the wind).

Mark \\.

CPMcGraw

06-25-2008, 10:06 PM

...Also, take a look at the fin orientation in the three stages. Because they do not overlap, the fins for the two boosters are in line. The sustainer's fins do overlap those of Booster #2, but I twisted the stage so that the sustainer fins are as close as possible to Booster #2's fins. I did this to try to minimize the drag as much as possible...

You know, if you had asked GHS about this, he would have recommended rotating the three stages so that each set of fins had their own path through the airflow. This would have maximized the corrective effect. Placing the fins inline with each other, according to this theory, reduces the corrective effect because the following fins do not have the full benefit of the airflow working on them.

As with any theory, however, YMMV... :rolleyes:

CPMcGraw

06-25-2008, 10:08 PM

...Launching off of a 60" rod (it needs at least a 48" rod), a combination of a D12-0, a C6-0 and an A8-5 will nicely lift the sustainer to 1225', even in 3-7 mph winds (with the launch rod angled 6.5° with the wind)...

Curious...

What does RockSim show to be the altitude reached by the sustainer alone on a C6-5 or C6-7?

Mark II

06-25-2008, 10:26 PM

Curious...

What does RockSim show to be the altitude reached by the sustainer alone on a C6-5 or C6-7?
In 3-7 mph winds, and a 60 inch rod angled 6.5°, it shows that the sustainer will reach 548 feet on a C6-5, with a dv of 22.39 fps. On a C6-7, it will go 554 feet, with a dv of 73.87 fps (very late deployment).

Mark \\.

Mark II

06-25-2008, 10:38 PM

In 3-7 mph winds, and a 60 inch rod angled 6.5°, it shows that the sustainer will reach 548 feet on a C6-5, with a dv of 22.39 fps. On a C6-7, it will go 554 feet, with a dv of 73.87 fps (very late deployment).

Mark \\.
It also doesn't reach a stable speed until it has gone about 50.75" on either motor.

Mark \\.

Mark II

06-26-2008, 02:31 AM

You know, if you had asked GHS about this, he would have recommended rotating the three stages so that each set of fins had their own path through the airflow. This would have maximized the corrective effect. Placing the fins inline with each other, according to this theory, reduces the corrective effect because the following fins do not have the full benefit of the airflow working on them.

As with any theory, however, YMMV... :rolleyes:
I've looked at it from that perspective, too. But the last thing that this rocket needs is more fin-induced stability; it is so prone to weather-cocking as it is (as, I'm sure, most 3-stagers are). More thrust, or more thrust-induced stability, is what this design really needs, as you pointed out many posts ago. I tried rearranging the way the fins on all three stages were oriented toward each other as a possible way to further reduce drag and to get more out of the thrust available in current BP boosters. But I realize that doing so may cause the stack to need more launch rod length before it reaches a stable speed.

By the way, I couldn't get the 2-stage configuration (booster 2 and the sustainer) to be stable without having to revert to using a D12 in booster 2. A C6-0 just won't give the shorter stack enough of a kick.

Anyway, I think that the latest tweaks have given it an incremental improvement. The original ST-7 sized design, in contrast, does fine in RockSim, and I hope to do some real-world testing of my built version soon.

As a next step, I will try substituting ST-13 for the LT tubing. It can still use the same nose cone; I would just have to build up the shoulder a little bit. Doing this, and reducing the motor size in the upper two stages to 18mm, creates an existential dilemma, though: is it really an SLS model, then? :eek: :rolleyes:

I could probably make a 24mm minimum-diameter version of it that would fly better, but it might need a custom nose cone in that case, and it wouldn't be in SLS-scale anymore.

At any rate, this has been a learning experience for me, and I'm building on that with another SLS-type design that I'm working on.

Mark \\.

James Pierson

07-08-2008, 07:57 PM

Small request for all you Computer Genieuses here on the Forum ;) .

I would like to update my PDF copy of all the Semroc balsa parts. I have noticed quite few new nose cones and other parts posted and updated on the Semroc site :D . If a person just does a search for "balsa" on the Semroc search engine you will see what I mean. Can someone post an updated PDF with all the pictures of the Semroc balsa parts, Please :rolleyes: . I do not have the knowledge to do this myself :o .

Thanks in Advance, JP.

James Pierson
NAR# 77907

Mark II

07-08-2008, 08:25 PM

Mark II

07-08-2008, 10:08 PM

OK, maybe it is a bit of a problem...:(

Because each page of the balsa parts list is HUGE,

I had to print the pages as individual Acrobat files. 14 pages = 14 Acrobat files.

With few exceptions, the individual Acrobat files are TOO LARGE for YORF (300 Kb file size limit).

I tried various ways to compress the files, but because the files consist almost entirely of graphics, FILE COMPRESSION WAS MINIMAL.

Besides the only type of archive that YORF will permit to be uploaded is .zip files, which REALLY DON'T COMPRESS GRAPHICS (or pretty much anything else, for that matter) AT ALL.

If you PM me with your email address, I will send you the 14 Acrobat files as attachments.

BTW, I can also combine the 14 pages into ONE GINORMOUS ACROBAT FILE, which might make it easier to search for a specific part, but it will take me a few hours to create it, and then I will have to send it to you by freight.

Mark \\.

Carl@Semroc

07-08-2008, 11:14 PM

The balsa parts and tubes are the sticking part of our proposed catalog. in the old 8 1/2 x 5 1/2 format, with small pictures, the nose cones were 6 pages alone. This was trying to get them in the familiar Estes/Centuri format. The rest of the balsa parts and all the body tubes came out to be about 15 pages! So... the catalog is on hold. Also, we have released about 30 new balsa parts and about 20 new tubes since the last cut. I think we will do one catalog for kits and another one just for parts.

But at a $2500 minimum order for about 1000 catalogs (with about 44 pages), we will have to let the trees live a few months longer!

Eagle3

07-09-2008, 07:15 AM

Any chance of releasing the catalog(s) in PDF from Semroc.com? A parts catalog would be a huge reference help. I made a pdf of Semroc balsa parts a while back that Scott posted on YORS, but it's way out dated. I use it all the time for scratch building reference and starting parts lists. It's a handy time saver to be able to refer to that without getting online. I can update the old one I did when I get time. Even make it smaller so it will print easier if you're not able to post an official one.

Ltvscout

07-09-2008, 08:40 AM

Any chance of releasing the catalog(s) in PDF from Semroc.com?
That would be great thing to have. Another vote for this until/if a printed catalog is available.

CPMcGraw

07-09-2008, 12:16 PM

Any chance of releasing the catalog(s) in PDF...?
That would be great thing to have. Another vote for this until/if a printed catalog is available.

I'll add my vote for PDF catalogs. It would certainly be cheaper to produce...

Pyro Pro

07-09-2008, 07:54 PM

I'll add my vote for PDF catalogs. It would certainly be cheaper to produce...

And me as well. If I'm not online, I generally just go by the pages I've saved off the website, which I update ever couple of months. But a nice, condensed PDF catalog would be great.

James Pierson

07-09-2008, 08:24 PM

Carl@Semroc
Also, we have released about 30 new balsa parts and about 20 new tubes since the last cut. I think we will do one catalog for kits and another one just for parts.

Thirty new balsa parts released by Semroc :eek: and we were never told in advance here at SVDT. :rolleyes:

STOP the presses I am gonna call the Seattle PI, New York Times and Chicago Daily! This news of new parts is what I live for as a rookie designer. Very News Worthy, Indeed.

James Pierson
NAR# 77907

CPMcGraw

07-09-2008, 10:47 PM

...we have released about 30 new balsa parts and about 20 new tubes since the last cut. I think we will do one catalog for kits and another one just for parts...

Another reason to go with PDF - by the time a printed (paper) catalog is ready to ship, the catalog is already out of date. With PDF, you could update the list several times in the year - quarterly (or even just twice-yearly) would be great for the kits catalog, and bi-monthly for the parts (which get added more frequently).

Pyro Pro

12-26-2008, 10:17 PM

So much activity over here!

Well, to break in my copy of RockSim 9, I thought I'd revisit the Tetraphelion, taking advantage of some of the new capabilities of v9. I actually started from scratch on this design, but it draws a significant amount of inspiration from the original. Changes include the addition of 2 more side pods, a 24mm sustainer, and generally a much larger design (nearly a foot longer at 42.9", yet still weighs in at ~5 oz dry). Even with 2 A8-3's (deployment mounts) and 2 B6-0's (booster mounts) loaded, it still manages 34 MPH by the end of a 36" rod.

Length: 42.9"
Diameter: 1.34" (ST-13; Sustainer), 2.04" (ST-20; Booster)
Weight: 5.37 oz

Flight Data:
C6-0, C6-0, C6-3, C6-3 ---> E9-8 . . . . . 3056' . . . . . Dv. 33.3 ft/s
with a theoretical E9-7, Dv. 6.91 ft/s

B6-0, B6-0, A8-3, A8-3 ---> C11-7 . . . . . 1086' . . . . . Dv. 13.2 ft/s

CPMcGraw

12-26-2008, 11:50 PM

So much activity over here!

Well, to break in my copy of RockSim 9, I thought I'd revisit the Tetraphelion, taking advantage of some of the new capabilities of v9. I actually started from scratch on this design, but it draws a significant amount of inspiration from the original. Changes include the addition of 2 more side pods, a 24mm sustainer, and generally a much larger design (nearly a foot longer at 42.9", yet still weighs in at ~5 oz dry). Even with 2 A8-3's (deployment mounts) and 2 B6-0's (booster mounts) loaded, it still manages 34 MPH by the end of a 36" rod.

Length: 42.9"
Diameter: 1.34" (ST-13; Sustainer), 2.04" (ST-20; Booster)
Weight: 5.37 oz

Flight Data:
C6-0, C6-0, C6-3, C6-3 ---> E9-8 . . . . . 3056' . . . . . Dv. 33.3 ft/s
with a theoretical E9-7, Dv. 6.91 ft/s

B6-0, B6-0, A8-3, A8-4 ---> C11-7 . . . . . 1086' . . . . . Dv. 13.2 ft/s

That's a beauty!

If you filter out all references to Semroc motors from your simulations, and just go with "standard Estes or Quest" motors, you can post this one in the "Designer's Studio" thread and I can include it in the Master List. This would be a welcome addition!

Pyro Pro

12-27-2008, 12:34 AM

Thanks;

At the moment, I haven't put any Semroc motors into my program yet, so as it stands, the file ought to be clean enough (Just Estes and AeroTech E9's, D21's, C11's, C6's, B6's, and A8's ATM). I'll probably just delete the reference to the original Tetraphelion in the rocket design description, but that probably isn't a huge deal in the first place.

I need to actually build some of these!

CPMcGraw

12-27-2008, 12:38 AM

Pyro Pro

12-27-2008, 12:43 AM

Oh, whoops!

Typo :o

CPMcGraw

01-01-2009, 07:47 PM

I just ran through all of the posts here in our "private thread", and I've located no less than 29 designs which are not yet available to the BARCLONE Master List. The biggest reason is the use of NYA Semroc motors, which we still cannot discuss away from the SVDT.

If you will locate your respective designs, try to re-motor the simulations with currently-available Estes-Quest-Aerotech motors and see if you can get reasonable Dv numbers and launch guide requirements less than 40" and 30" (for 48" and 36" rods, respectively). When you are satisfied with the results, please re-post them into the (new) BARCLONE Designer's Studio 2009 thread, and I'll get them added to the Master List on our Wordpress site.

Here's the list:

1. Venus Explorer
2. Micro Hustler
3. Hypertuse
4. Tiny Ivan
5. King Vidar
6. Mach I Dart with Thruster System
7. Lune R1 Plus 1
8. Skeeter
10. Mini Tom
11. Korviena
12. Triplet
13. Tensor
14. SLS Cyber III
15. Tetraphelion
16. Zondakhod
17. Nike-Smoke 13mm
18. Talos
19. Micro Bertha Probe Mk I
20. Micro Bertha Probe Mk II
21. G Harry Stine Basic Design
22. Deimios
23. Rayfinder
24. Zoot
25. Sky Master
26. Baracuda
27. Nova Hi
28. Hyper Jett

This represents 28 designs that will get us closer to the 600-design milestone. A few other designs are dependent on motors and components that don't yet exist, so they're not included here. But if these can be re-worked, let's get them available.

Thanks!

snaquin

01-01-2009, 09:39 PM

Craig

I'd be happy to look over my designs you listed.

I also posted two SLS kits over in the Potential SLS kits? thread.

http://forums.rocketshoppe.com/showthread.php?t=1408

I had a SLS Magnum-D Hornet & a SLS Lune R-1 design there. The SLS Lune R-1 has been flight proven and I have a few build and finish pics of that one.

Would BARCLONE be interested in either of these?

.

CPMcGraw

01-01-2009, 10:28 PM

CPMcGraw

01-02-2009, 02:52 PM

Carl,

It's been quite a while since this was mentioned, but have you had any additional requests for a smaller set of Nike-Smoke nose cones? I'm looking at revising this design (http://forums.rocketshoppe.com/showpost.php?p=22335&postcount=116) and was wondering if you could add it to the list? I think my pattern in the RKT file is close for measurements.

Mark II

01-02-2009, 07:43 PM

snaquin

01-03-2009, 07:24 PM

Steve,

Thanks for the heads-up. It's been some time since I looked through all of the SVDT threads. Yes, I'd be interested in those as well!

I revised and posted one of the two you mentioned on your list as well as the two I mentioned. I'll look for others.

I'm going to rework the Mach-1 Dart file. All my FSI files I entered into RockSim were originally version 5 files and used FSI parts so I need to rework them with Semroc parts. I have flown the Mach-1 Dart many times using a motor mount in a mock up booster and it always flew well.

.

CPMcGraw

01-05-2009, 07:07 PM

The acronym stands for "Low Earth Orbit Payload System".

This is a design that uses the new (not yet announced) ST-6 tubes that Carl has announced for his "Deci-Scale" series. They're a little larger than ST-5, but smaller than ST-7 (well, duh... I knew that! :o ). You can fit a length of ST-5 inside them and still need centering rings (narrow, fragile, but still possible) for use as motor mounts.

Length: 20.75"
Diameter: 1.34" (ST-13)
Fin Span: 3.10"
Weight: 1.15 oz

1/2 A3-4T......282'......Dv 8 FPS......36" x 1/8" rod

Once Carl officially reveals the ST-6 tube and components, I'll post this to the "Studio" thread.

Enjoy!

CPMcGraw

01-16-2009, 07:57 PM

Mark II

01-17-2009, 11:44 AM

Over on the Designer's Studio thread (mainstream area), RKT2K1 shared his version of the Centuri Bulldog in RockSim format. His simulation runs were marginal and had very high Dv numbers. I noticed in the kit instruction scans that the B8 and C5 were listed, which made a lot of sense. This design appears to have been a pig from the get-go; yet the performance even with the listed core-bores was not really in the ballpark. So I tried the design out with some of SEMROC's Secret Sauces, and spotted an interesting simulation. The B14-4 has a very nice flight profile, with a Dv of only 15 FPS, and an altitude of 263'.

Now, I've never personally had any experience with this model. I'm only going on what Bill [RKT2K1] described in his post. The simulation he worked up seems to be on-par with his recollections of the original kit. Is there anyone here in the SVDT who has or had the Bulldog kit? What are your recollections as to its performance, and what engines did you see the best flights with? Am I wrong about the kit being more a sow's ear instead of a silk purse?
I don't recall if it was discussed in that post, but why not just upgrade the whozis mount to 24mm? The tailcone adapts down from BT-70 to BT-55, so instead of sticking a BT-20 mount in there, why not go with a BT-50/ST-9 mount instead? Heck, you could even go with an LT-115! Or a 3 x BT-5 cluster! I don't know how these would sim, but I would think that there ought to be something there that works. I think that the Centuri Bulldog is a very attractive model, and it is one that I would certainly want to build.

Mark \\.

Pyro Pro

02-21-2009, 12:28 AM

Though, a bit of bad news first. It seems like RockSim doesn't like my design when it comes to getting any useful flight-testing results, so in that respect, it is "virtually-unproven" until Apogee works out what's wrong (I'm going to email them later this weekend, but I'll wait first to see if someone is able to point out something that I'm missing).

That being said, I now present the first functional strap-on design for this thread (I think). I was at a loss for a name while working on it, so I just called it, "Straponski" until I can think of something better. I thought it sounded vaguely Russian (even though the design is loosely inspired by the Ares V). It is based on ST-20 for the core vehicle, which has a large (33.9 cu. in.) payload for launching cameras, experiments, etc. I have a somewhat limited knowledge of how passive strap-on designs work; what I've gathered is that the strap-ons are designed to accelerate faster than the core throughout their motor's burntime, thus holding them in place, and at burnout, drag forces them to slide off their rails/holders, as the core continues burning. I didn't actually run calculations on the core vehicle and strap-on approximations to see if the acceleration worked for various motor combinations, I just guessed that an 18mm motor mount in a ST-11 based, lightweight booster would accelerate faster than a big, long piece of ST-20 on an E9 or other longer-burning core motor (carring a payload would expand the motor range a good bit, if any of these setups are too close to call). Anyway, I also wanted the strap-ons to not just fall away, but "peel off" like they do on real space vehicles. The way I planned on doing this is just something I came up with in my head (and later sketched out on paper), and involves a short section of dowel rod, mounted horizontally, attached to the base of the core stage. The strap-ons would have a corresponding section/slice of launch-lug material towards their base, and when the standard strap-on lugs have allowed the booster to slide backwards, instead of falling off the rocket, the launch leg slice would hit and wrap around the dowel, creating a hinge on which the base of the booster pivots as it falls away. A small piece of balsa might be needed up higher on the booster to give it a slight "kick" to get the rotation started, to make sure it doesn't just hit the dowel rod and get stuck there. I've tried to make the RockSim file as accurate as possible, so it will probably make more sense when you look at what I've set up by looking at the 3D exports and RKT file. The boosters can be held in place at launch using a piece of thread that wraps around the lower attachment point and over the nozzle of the motor; if it lights, it will burn through the string, freeing the booster to slide; if there is a misfire, the string will remain to keep the booster latched in place--just in case it should happen to ignite late. The completed rocket comes out at exactly 36" long (I actually had to modify the nose cone a bit to do this... it was originally 4.5" long, but when the length of the rocket came out to 35.7500" long, I couldn't pass up the opportunity to make it an even 3 feet. So it's got a 4.75" ogive now.).

Now, to those simulation results...

The rocket only weighs about 6 oz empty, so it ought to have decent performance on 2 18mm's and a 24. However, RockSim has been acting strangely, and is only giving me altitudes around 50-100 feet for all flights (For instance, 2 C6-3's and an E9-6 went to 51 feet, maxed out at about 19 mph (according to the flight summary--though according to the data plot, it really only reached 8 mph), had an optimal delay of 0.19 seconds, and strangest of all, apparently reached stable launch speeds at -36.37" (that's NEGATIVE!). Looking at the 2D flight profile, it almost seems like it's simulating a ridiculously high Cd, because the rocket just chugs along while under power, stops right after burnout, freefalls *very* slowly, deploys its parachute and drops very quickly (relatively; DR's are comparable with other rockets, but the rest of the flight goes so slowly that descent under parachute is actually the fastest part). However, a high Cd value would not explain the strange -36" minimum launch rod length, nor the fact that, according to plots, it really cleared the rod at less than 2 mph, and yet it continues to fly in a stable manner (according to the simulation results, it apparently cleared the launch guide at 18.7 mph... I give up). Also, RockSim is rendering strange tube-like objects when I look at the 2D base view (see attached) that I am at a loss to explain (I didn't create them, and they show up nowhere else). Similar results happen, even when I try to simulate with the strap-ons off (ie, checking the "Mark this pod as ejected." box in the Pods interface), flights on a single E9 barely differed from the flight on E9's and C6's.

So, as far as I can tell, something is just very wrong with the program, or I really messed something up. I'm using the lastest version (9.0.2f72), as far as I know.

Anyway, enjoy, if possible.

Straponski
Length - 36"
Diameter - 2.04" (Core; ST-20), 1.17" (Strap-ons; ST-11)
Fin span - 8.04"
Weight - 5.89 oz

Simulations

n/a

Pyro Pro

02-21-2009, 03:56 PM

Whoops, of course I forgot the launch lugs. I was tired! :rolleyes:

I'll add them on in a bit; ought to just be a couple of 3/16" lugs (2" long), spaced about 6-10" apart, centered in between the fins of the core tube.

Pyro Pro

02-23-2009, 09:28 PM

Well, turns out the problem was that all the tiny "fins" I had on the outside of the pods to simulate the strap-on holding mechanisms was really messing with the drag coefficient, which was up around 300 :)

Cd override was set to 0.80, and the results look much more respectable!

Flights look fairly nice on black powder, especially the (2x) B6-2 and E9-4 (though an E9-5 would give a bit better Dv's, 4.5 would be even better) flight, which clears a 36" rod, stages at about 80-100 feet, and stays under 1000. This ought to really fly even nicer with high-thrust A's or B's in the pods for demo flights.

[2] B6-2 -> E9-4 ..... 992' ..... Dv 18.7 ft/s ..... 3/16" x 36"
[2] C6-3 -> E9-5 ..... 1196' ..... Dv 2.4 ft/s ..... 3/16" x 36"
[2] D10-3 -> F12-5 ..... 1735' ..... Dv 9.1 ft/s ..... 3/16" x 36"

Now I need to find time to build it! I've always liked parallel-staged designs, but I've never built one before, just read reviews of kits and diagrams of how they work.

(It turns out those strange ring things in the base view were artifacts of the centering rings inside the pods. I removed the rings for now, since they hardly add any weight, and aren't hard to add back in [rear ring is a double-layered piece of fiber, 0.1" thick, forward ring is standard 0.05"].)