Scratch built version 2

[my65pan]

I made this little rocket up this morning after destroying version 1 yesterday when the motor blew instead of the chute. I re-used the nosecone, but everything else has been replaced. I made this one a little shorter and with a different fin shape. We'll see how she flies soon.

Homebrew nylon nosecone $0
Packing tube body $0
Cable modem box for fins $0
Plastic tube from a new drill bit for lug $0
Bent strip of aluminum motor clip $0
Seeing my sons face when it lifts off, Priceless

Markhttp://i98.photobucket.com/albums/l260/my65pan/000_0159.jpg

[JSP]

Let us know how she does!

[barone]

Did you ever figure out why the engine blew instead of the parachute? Just not held in tight enough?

Don
NAR 53455

[my65pan]

Did you ever figure out why the engine blew instead of the parachute? Just not held in tight enough?

Don
NAR 53455

What happened was that it had a hard landing on the previous flight and bent my makeshift motor clip, for lack of a better word. I thought it would still be OK, but found out different.

I took the new one up to the park with the last motor I have, but I forgot the ignitor, so we watched some guys fly remote control airplanes instead. I'll let you guys know how it goes though.

I did find that shipping tube is too porous (sp) to take spray paint well though :-).

Mark.

[CPMcGraw]

I did find that shipping tube is too porous (sp) to take spray paint well though :-).

Mark.

A few quick tips to offer for your 3rd attempt... (You WILL have a 3rd attempt, right??? :) )

The shipping tube is not a bad start. I've seen some thin-wall white-outer-layer shipping tubes from Staples that I might try myself for an odd-rock project. For those fins, though, try laminating two layers of that cardstock together, and press them between two solid, heavy, flat objects to dry. If you can detect any sort of grain pattern in the cardstock, criss-cross the grain in each layer, and your dimensional stability will improve (less warping).

I think I see some type of hot-glue holding everything together on this model. Grab a bottle of Titebond II from Lowes or Home Depot. You'll find the adhesion to be far superior under the stress from hot motors, quick accelerations, and hard landings. This is what most of us use for general construction. Elmers also makes a professional-grade yellow construction glue, which I've used myself. I keep coming back to the Titebond II because of the "grab" it has when assembling a model.

For finishing the model, try a good sprayed-on coat of Kilz as your first primer, and let it dry several days before sanding it. This will seal every pore in the paper.

Every flight is a learning process, but it's also supposed to be fun. I personally enjoy the building process for the challenges it offers; but I also enjoy flying when I get the chance, just to see my birds strut their stuff.

[my65pan]

Thanks for the tips and I'm sure there will be many more rockets to come. The only reason I'm using the materials I am are that I already have them here at the house. You are correct on the hot glue, it was also what I happen to have, the carpenters glue I would have used was all dried up. I'll look for Titebond II, sounds ideal.

I was thinking of thinning out some Elmers with some liquid latex and making a sort of shadetree sanding sealer for the tubing I have, again because I have the latex and tubing, just need the Elmers. I like the lamination idea for fins, I think I'll run with it once I find some more cardstock.

I plan on ordering some actual rocket body tubing, but for now I think I'll fabricate the rest because that's what I enjoy the most about every hobby I have.

Motorcycles
Ham radio
A little bit of guitar
and now, Rockets

Mark.

[barone]

I plan on ordering some actual rocket body tubing, but for now I think I'll fabricate the rest because that's what I enjoy the most about every hobby I have.

Motorcycles
Ham radio
A little bit of guitar
and now, Rockets

Mark.

Mark,

Just to let you know, you can actually fabricate your own body tubes. Use an expended motor and roll paper or cardstock around it. Can be pretty stout if you don't go with one too long. You can even use cardstock to make conical shaped nose cones.

Don
NAR 53455

[Green Dragon]

Mark,

Just to let you know, you can actually fabricate your own body tubes. Use an expended motor and roll paper or cardstock around it. Can be pretty stout if you don't go with one too long. You can even use cardstock to make conical shaped nose cones.

Don
NAR 53455

I've never had much luck with rolling my own tubes, but have made a couple 'iffy' ones from gummed paper tape.

I have ,however, used the rolled paper cone method - see attached photo - that's a paper towel roll, rolled paper cone ( with about 20 coats of titebond for strength amd rigidity), and leftover balsa fin stock.
made the centering rings from corugated cardboard, witht he only commercial parts being the motor tube and launch lugs.
made that years back to demonstrate to a middle school group that it was easy to build from nothing - had another with a turned balsa cone , but it was damaged by a late chute deployment ( like 2 feet from the ground ) .

also, no problems in painting the un-sealed tubes, just use a couple coats of a good primer, then sand the 'fuzzies' off, and spray multiple coats on until it looks ok - might never get a glossy show-quality finish, but mine look ok to me .

keep posting, and building, it's addicting, lol .

~ AL

[JSP]

Way back millions of years ago when I was a serious competitor, I made mini engine sized body tubes and nose cones out of notebook paper (single thickness) and carbon or very thin ply fins. It's amazing how a cylinder will actually hold up under stress. However, one range box slides across a back seat and you can lose a whole fleet! :eek:

[my65pan]

Well, I still haven't tried #2 yet, but I did turn a dummy "C" size motor from aluminum for mocking things up with. I also found some carboard tube that a new long drill bit came in that will work perfect for motor tube, and a whole bunch of short plastic tubes for launch lugs. At work I also sheared of a handful of stainless steel strips to make motor hooks from. Where is the best place to order an assortment of cardboard tubing from?

Mark.

[snaquin]

Well, I still haven't tried #2 yet, but I did turn a dummy "C" size motor from aluminum for mocking things up with. I also found some carboard tube that a new long drill bit came in that will work perfect for motor tube, and a whole bunch of short plastic tubes for launch lugs. At work I also sheared of a handful of stainless steel strips to make motor hooks from. Where is the best place to order an assortment of cardboard tubing from?

Mark.

I get mine from Semroc

http://www.semroc.com/Store/Products/BodyTubes.asp

The ones marked "large body tubes" are the heavy duty ones with thick wall

[my65pan]

I still haven't flown version 2 yet, but I have a good start on version 3. This one is a bit more involved. Today I machined the nose cone, and the reducers to transition between body tubes from white Delryn.
I also turned a pair of stamps to stamp out my centering rings, and bent a piece of spring steel for a motor hook. All of the tubing is castoff tooling sleeves from work. The heavy cardstock on the left was liberated from a three ring binder for fins. This stuff is addicting!

Any suggestions for a shape for the fins?

http://i98.photobucket.com/albums/l260/my65pan/000_0161.jpg

[my65pan]

Here's a mock up shot.

http://i98.photobucket.com/albums/l260/my65pan/000_0163.jpg

[JSP]

I vote trapazoid....but I usually do.....

[barone]

I think something like the old Estes Cobra fins would look good on that.

Don
NAR 53455

[CPMcGraw]

I still haven't flown version 2 yet, but I have a good start on version 3. This one is a bit more involved. Today I machined the nose cone, and the reducers to transition between body tubes from white Delryn.
I also turned a pair of stamps to stamp out my centering rings, and bent a piece of spring steel for a motor hook. All of the tubing is castoff tooling sleeves from work. The heavy cardstock on the left was liberated from a three ring binder for fins. This stuff is addicting!

Any suggestions for a shape for the fins?

We have 'em now! :D :D :D

What are the lengths and diameters of those tubes and the "visible", or external portions of those turned components? I could whip up a RockSim file to find an optimum shape...

[my65pan]

Thanks CP, the lower tube is 1.275 dia X 3.65 long, reducer is .56 long. Center tube is .890 dia X 4.35 long, reducer is .50 long. Top tube is 1.165 dia. X 3.95 long. The nose cone is 2.15. I primed the tubes last night, today I'll pick up some Tite bond II and a few other items and start assembly.

I know this may be frowned upon, but I just have to know how the aluminum rocket flies. Since my son has attached himself to the first one and won't let me fly it, I've built another slightly modified version. I live in Phoenix, so I'll take it out to the open desert to try it. I'll post a pic of it this afternoon if you like, gotta go to work.

I hope you guys don't dis-own me.

Mark.

[Tweener]

May I suggest extra long launch control line and a makeshift bunker of some sort - just to be on the safe side? ;)

[JSP]

Inside a car works fairly well....except for the possibility of broken glass...

[CPMcGraw]

Thanks CP, the lower tube is 1.275 dia X 3.65 long, reducer is .56 long. Center tube is .890 dia X 4.35 long, reducer is .50 long. Top tube is 1.165 dia. X 3.95 long. The nose cone is 2.15. I primed the tubes last night, today I'll pick up some Tite bond II and a few other items and start assembly.

I know this may be frowned upon, but I just have to know how the aluminum rocket flies. Since my son has attached himself to the first one and won't let me fly it, I've built another slightly modified version. I live in Phoenix, so I'll take it out to the open desert to try it. I'll post a pic of it this afternoon if you like, gotta go to work.

I hope you guys don't dis-own me.

Mark.

Mark,

Additional questions...

What is the wall thickness of those tubes, and are those Delrin components hollow completely through? I'm setting up the RockSim simulation to get the fins shaped right, and I'm finding the component weights a bit whacked out. If you've got a postal scale, could you give me an idea of what your total weight is right now, without fins? That will also let me know if I'm in the right ballpark...

[my65pan]

It won't happen for some time, but I was thinking behind the truck, minus my son.

CP, I don't have a scale sorry. The reducers are hollow with a wall thickness of approx .05 all of the way through except where the shoulder is, the nose cone is hollow also with about a .05 thickness at the skirt and about .09 past that. The tip of the cone is much thicker though, I didn't have a long and narrow enough boring bar to get down there, so I step drilled it out as well as I could. the tubes are .045 for top & bottom and .065 for the middle one. I hope this helps.

On another note, a guy at work gave me a box full of rockets, a launcher, and a handful of assorted engines today. All in an Estes range box. There was even an unbuilt Corkscrew kit in the box.

Mark.

[my65pan]

I launched version II 4 times without a hitch, and then it lawn darted on me. I don't know why, it had a C6-3 in it just like the previous launch and it didn't blow the streamers or the motor. Oh well, right after that a park cop came and told me it is illegal to launch in a City of Phoenix park. I guess it's illegal to have fun anymore!

Mark.

[CPMcGraw]

CP, I don't have a scale sorry. The reducers are hollow with a wall thickness of approx .05 all of the way through except where the shoulder is, the nose cone is hollow also with about a .05 thickness at the skirt and about .09 past that. The tip of the cone is much thicker though, I didn't have a long and narrow enough boring bar to get down there, so I step drilled it out as well as I could. the tubes are .045 for top & bottom and .065 for the middle one. I hope this helps.

Mark.

Helped quite a bit, Mark. I was able to get a more accurate simulation with your numbers...

Try out the fins I have here. The performance is not too shabby given the high weight, although you might want to use a 48" rod instead of a 36" rod for both motors. It takes all of 38" of continuous launch guide length before the rocket reaches safe flying velocity. Dv, if you haven't followed our threads before, means Velocity at Deployment. This is how fast the rocket will be moving when it pops the cork...

Some specs:

B6-4......267'......Dv 17 FPS......Margin of Stability 3.03 (very stable)
C6-5......769'......Dv 12 FPS......Margin of Stability 2.81 (very stable)

Length: 15.16"
Diameter: 1.275"
Fin Span: 4.22"
Weight: 2.65 oz (rather heavy)

[my65pan]

Thanks man! I ordered some blank balsa fin stock from Semroc so I'll use that fin design. Can you give me dimensions?
I realize it is a heavy model. I think most of that is due mostly to the heavy tubing. I lightened the plastic pieces as much as I could. I'm gonna run with it.

BTW
I called Phoenix PD and they don't know anything about any ordinance against launching in city parks. The desk Seargent told me to have the park ranger prove it was illegal or call a real cop. Does anyone know the real scoop for Phoenix parks?

If model rockets are illegal in parks, baseballs, Frisbees, soccer balls, and of course hot dogs, lest someone choke on city property, should also be banned.

Mark.

[JSP]

If model rockets are illegal in parks, baseballs, Frisbees, soccer balls, and of course hot dogs, lest someone choke on city property, should also be banned.

Mark.

I usually try to not eat public property...Who knows where it's been! :eek:

[Royatl]

I was looking at that and thought.... I've seen that somewhere before (of course, there's nothing new under the sun). So, I skimmed through my files and found this...

[Royatl]

BTW
I called Phoenix PD and they don't know anything about any ordinance against launching in city parks. The desk Seargent told me to have the park ranger prove it was illegal or call a real cop. Does anyone know the real scoop for Phoenix parks?

Mark.

Wish we'd known last week that you were from Phoenix. The 48th National Model Rocket Championships (NARAM 48) just ended at Rainbow Valley yesterday.

You can see what you missed at www.naramlive.com.


The people at http://www.sssrocketry.org/ (Superstition Spacemodeling Society) can probably tell you about any ordinance in the Phoenix area.

[CPMcGraw]

Thanks man! I ordered some blank balsa fin stock from Semroc so I'll use that fin design. Can you give me dimensions?

Mark,

The fin image is full-size already. Just print it out onto cardstock without changing anything to create a template, or print three copies of it onto a sheet of self-stick label stock for a set of ready-to-cut balsa fins.

For the record, though, the root edge is 3"...

Just wait until you start ordering tubes and other goodies from SEMROC...:rolleyes:

[my65pan]

Hmm, the image takes up my whole screen when I open it. I already ordered some tubing, chutes, etc. from Semroc :-).

[CPMcGraw]

Hmm, the image takes up my whole screen when I open it. I already ordered some tubing, chutes, etc. from Semroc :-).

What are you opening it up in? I use PhotoShop Elements 1, but you could use The GIMP (which is free) and the image should open up correctly...

[my65pan]

I was looking at that and thought.... I've seen that somewhere before (of course, there's nothing new under the sun). So, I skimmed through my files and found this...

There was no picture :-(.


I downloaded The Gimp and it wouldn't open it either, I was just clicking the thumbnail before and opening it in Explorer.

[barone]

Tif images, at least for me, need to be downloaded to your local drive and then opened.

Don
NAR 53455

[my65pan]

I still haven't gotten those images to work for me. I'll sketch the fin shape onto paper, no problem.

On another note, apparently there was a new batch of Park Rangers and I got one. There are no ordinances against model rockets in City of Phoenix Parks.

[my65pan]

I have the fin shape laid out now, thanks CP. I think I've been making my fins a little on the large size so far. When I scaled your image onto paper with a 3" root edge it looked tiny, but it looks perfect when I hold the pattern next to the mocked up body.
I should get the balsa, etc from Semroc soon and then I'll be in business.

Mark.

[Royatl]

There was no picture :-(.


I downloaded The Gimp and it wouldn't open it either, I was just clicking the thumbnail before and opening it in Explorer.

You must have your browser locked down pretty tight, or you're missing some essential .DLLs.

I just downloaded the picture and opened it in GIMP 2.2 with no problem.

my image is a plain old .TIF file. I created it in Epson Scan and made it a bit smaller in Paint.Net. (http://www.getpaint.net -- free download)

[my65pan]

I've never had a problem with TIF files before. Oh well.

[my65pan]

Does anyone have any ideas for a paint scheme for version 3? I'm calling it Scavenger III to keep with the whole scratch built theme. I cut the fins out last night and started assembly this morning. I assembled the Sidewinder kit this morning also.

Royalt, what is the Tif image of? I downloaded it again and tried to open it to no avail, apparently there is something wrong on my end.

[barone]

Does anyone have any ideas for a paint scheme for version 3? I'm calling it Scavenger III to keep with the whole scratch built theme. I cut the fins out last night and started assembly this morning. I assembled the Sidewinder kit this morning also.

Royalt, what is the Tif image of? I downloaded it again and tried to open it to no avail, apparently there is something wrong on my end.

It's a picture of a rocket that won a Centuri Design of the Month Contest. It looks similar to your design. After downloading the image (saving it to your hard drive), try to open it using Windows Picture and FAX Viewer. I'm not having any trouble with it. Here a jpeg version.

Don
NAR 53455

[my65pan]

Wow, that does look real similar doesn't it? I can't take credit for the design, it is what it is as far as the body goes, and the fin design is from CP McGraw.

http://i98.photobucket.com/albums/l260/my65pan/000_0173-1.jpg

[my65pan]

Well, I launched Scavenger III this morning. OK on B engines. Unstable on a C6-3. Recovery was no problem on either flight, but I think I'm done flying this one.

[CPMcGraw]

Well, I launched Scavenger III this morning. OK on B engines. Unstable on a C6-3. Recovery was no problem on either flight, but I think I'm done flying this one.

The tube weights must be a bit heavier toward the rear of the model than we calculated in RockSim. That same design using SEMROC's thinner-walled stock would likely have flown with no instability issues...

Still looks great!

[my65pan]

Hey, I had fun building it. I think I like building more than launching anyhow. I have 4 or 5 that I haven't even tried yet now. Funny thing is, on the other hand I have no interest in paint, decals, etc. I just want to fly 'em once they are assembled.