Initial Motor Requests

[Mark+3]

What motors would everyone like to see Semroc release first?

Carl: "The order of release will be based on discussions here. The smaller 18mm and under machine is being built first. Engines over 70mm long or over 18mm in diameter will be done on the larger machine."

Carl: "The absence of 1/2A and A boosters is a good example of why there is little new or innovative kits to use low power boosters. The places available to fly two-stage rockets with a minimum of a C6-0 is growing smaller all the time. If the C6 was a C12 or C20, at least you could do low altitude two-stage rockets with heavier designs. That is just my opinion. I always liked two-stage rockets that you could see and recover. I also liked the B14-0 because I could make the rocket a little heavier."

13mm 1/2A and A boosters, 18mm A and B power boosters are first on my wish list.
Obviously the B-14 is in high demand as I don't believe a day goes by that someone doesn't publicly mourn it's absence

[Royatl]

What motors would everyone like to see Semroc release first?13mm 1/2A and A boosters, 18mm A and B power boosters are first on my wish list.
Obviously the B-14 is in high demand as I don't believe a day goes by that someone doesn't publicly mourn it's absence

Definitely with the 13mm motors. I'd like to be able to fly the Fire Fly! and I'd like to be able to build and fly a Midget.

[CPMcGraw]

I highly agree -- 13mm boosters, 18mm A and B boosters, and better variety of power choices among both 13mm and 18mm A and B single-stage motors. "C" class is nice, but I'm not able to take advantage of them as much where I fly.

[Doug Sams]

What motors would everyone like to see Semroc release first?While making motors equivalent to the commonly available, medium thrust motors already out there makes sense in the long run, I'd say that the differentiated products should be first. 29mm cored BP motors - woo hoo! I never go to play with any of these (eg, F100, et al) but I am chomping at the bit.

Likewise, I want to see cored 24mm versions, too. D30, E40. In 18mm, a C20 to go with the B14 (if it's possible...to fit in that much impulse/powder along with a deep core).

If the reliability problems of cored motors can be solved/avoided, then it's possible to position these fast burn/high thrust motors against medium thrust motors. IOW, almost any rocket than can fly on a B6-6 can fly on a B14-6 without adverse consequences. So a high thrust motor can be sold into mainstream applications as well as heavy lift.

OTOH, while low thrust motors are fun, they can't cross over into medium thrust applications without lots of complaints and/or warrany claims. So the high thrust motors should have the best potential for getting a return on investment in a timely fashion. IOW, save the low-thrust and medium thrust motors for later.

I wonder about reliability and cost. I've heard that some large BP motors had fiberglass cases. If that's what it takes, then I wonder if the added cost will pose retail price problems. I'm willing to pay extra, but I worry about others.

Seeing Carl's old catalog along with the AVI motors, the idea of adjustable delays is stuck in my head. If I understand it correctly, a booster motor plus DECAP makes a delay motor, right? Will it be possible for the user to trim the delay before gluing it in? Will it even be sold in pieces to allow that?

The potential beauty of this is that only two pieces are required (plus glue) to make a myriad of delay options. Looking at Aerotech thru an accountant's eyes, I was able to learn the huge costs they have tied up in delays and delay spacers. They have over 20 of each for their 29 and 38mm motors. Cesaroni has 1. They use the same delay grain in all 38's and (I think) 54's. It may be 13 secs in one motor and a 15 in another, but it's the same delay. 1 inventory item. (BTW, with BP motors, there will be no variations due to motor burn pressure since the delays don't light until motor burnout.)

From a manufacturing perspective, delay grains would be cranked out along with 0 delay motors. Advanced users - us - would buy these two piece motors and use them however we need - eg, C20-0, C20-5, C20-10. But ordinary retail channels can be served with pre-trimmed, pre-glued products as well. However, these would be built up using the same two pieces. There would be no large factory inventories of pre-trimmed, pre-glued motors.

Again, I'm not sure it's possible to build a trimmable delay for BP motors. One experiment I have yet to try is gluing an AT delay into a BP booster motor. If it will light, then it will be possible to trim custom delays with that method. I do wonder if having an APCP delay and BP together poses any sore of shelf life issues.

I also wonder about assembly issues. There needs to be a way to reliably glue the delay in without getting glue on the delay face while getting a good seal around the delay.

Anyway, the idea of a universal motor-delay combo is very tantalizing. There's a potential for having wide variety without proliferation of parts/part numbers.

So, in summary, I'll take:

29mm F100-adj
24mm E40-adj
24mm D30-adj
18mm C20-adj
18mm B14-adj
13mm 1/2A8-0T

Doug

[Mark+3]

I'd say that the differentiated products should be first. 29mm cored BP motors - woo hoo!

Likewise, I want to see cored 24mm versions, too. D30, E40.

Per Carl: " The smaller 18mm and under machine is being built first. Engines over 70mm long or over 18mm in diameter will be done on the larger machine."

[billspad]

Again, I'm not sure it's possible to build a trimmable delay for BP motors. One experiment I have yet to try is gluing an AT delay into a BP booster motor. If it will light, then it will be possible to trim custom delays with that method. I do wonder if having an APCP delay and BP together poses any sore of shelf life issues.

Doug

You're going to have to cut it really short. Most of the delay element is burned while an APCP motor is burning. What's left burns at something like 1/32" per second so you're going to have a thin piece of rubbery stuff that's going to need a bulkhead to keep it from blowing out too soon. What you end up with may work but I think Carl's DECAP system is a lot simpler.

[Eagle3]

... 29mm cored BP motors - woo hoo! I never go to play with any of these (eg, F100, et al) but I am chomping at the bit.

The Rocketflite 29mm G100 is one of the most kick ass motors I've ever used. It was definitely jaw dropping. :)

[Carl@Semroc]

Good input! This is very well received. As I said, the first step is to get a large enough list to get started, get the list approved, then be able to ship samples for testing.

How about any other different sizes? The 15mm will probably be removed. It just does not have too many good uses.

About the port burning C engines, we did have a 3/4C19 that was reliable in testing, but the full C was too much to drill. Maybe if it was done in two operations... In any case, it would be closer to a C32 with the same .3 second burn. Peak thrust of 60 N - 13 pounds. That looks like too much warranty work! >400G's in a Sky Hook!

[Carl@Semroc]

You're going to have to cut it really short. Most of the delay element is burned while an APCP motor is burning. What's left burns at something like 1/32" per second so you're going to have a thin piece of rubbery stuff that's going to need a bulkhead to keep it from blowing out too soon. What you end up with may work but I think Carl's DECAP system is a lot simpler.BP delay burns at about .05"/sec so it may be a little easier to trim than the BJ delays. But, I don't think we will release trim directions. I am not comfortable with 14 year olds drilling Black Powder. With every delay from 2-9 seconds available, there is not as much need to modify one to get a particular delay.

[Eagle3]

Good input! This is very well received. As I said, the first step is to get a large enough list to get started, get the list approved, then be able to ship samples for testing.

How about any other different sizes? The 15mm will probably be removed. It just does not have too many good uses.

About the port burning C engines, we did have a 3/4C19 that was reliable in testing, but the full C was too much to drill. Maybe if it was done in two operations... In any case, it would be closer to a C32 with the same .3 second burn. Peak thrust of 60 N - 13 pounds. That looks like too much warranty work! >400G's in a Sky Hook!

Imagine clustering 3 of those C32's! <BG>

I guess I would suggest waiting on the 15mm until after the 10, 13, 18mm line. Then see if there is a real need/interest?

*still thinking about port burning C's* :D Imagine a Cobra or Ranger on 3xC19's!

[Carl@Semroc]

IOW, save the low-thrust and medium thrust motors for later.Once we get the engine machine cranking out a particular size, that whole lineage will be available. That means a B4, B6, B8, and B14 would all be released at the same time.I wonder about reliability and cost. I've heard that some large BP motors had fiberglass cases. We will avoid THAT! I think the fiberglass tubes would not work with our machine anyway. The potential beauty of this is that only two pieces are required (plus glue) to make a myriad of delay options. Looking at Aerotech thru an accountant's eyes, I was able to learn the huge costs they have tied up in delays and delay spacers. .....From a manufacturing perspective, delay grains would be cranked out along with 0 delay motors. Advanced users - us - would buy these two piece motors and use them however we need - eg, C20-0, C20-5, C20-10. But ordinary retail channels can be served with pre-trimmed, pre-glued products as well. However, these would be built up using the same two pieces. There would be no large factory inventories of pre-trimmed, pre-glued motors.We had originally thought about just that... Build 18mm boosters on a machine and DECAPS on another much smaller and simpler machine, then glue them together to "fill the matrix." When we ran the numbers, the projected retail price was:

B6-0 $2.05 each
B6-4 $2.30 each
DECAP $0.75 each

So to make them up separately "just-in-time" would bring a premium in price of about $.50 each. For people that want the best, it is still an option. The DECAP should be far more accurate in delay time. Once a DECAP is glued-in, it is permanent. We will have the top of the DECAP color-coded with the BBROYGBVGW scheme so the delay time would be known.

[CPMcGraw]

Good input! This is very well received. As I said, the first step is to get a large enough list to get started, get the list approved, then be able to ship samples for testing.

How about any other different sizes? The 15mm will probably be removed. It just does not have too many good uses.

I wouldn't discount this size just yet, Carl. This is an intermediate diameter between the standard 18 and the mini 13; I can see possibilities here for "B" class motors that can't be done in 13. If I had some power numbers that I could feed into RockSim's Motor Editor, I could run some tests on various designs. Since we don't have those numbers yet, I really don't know what the potential is.

Maybe that is something you could work up for us -- a RockSim motor chart with all of the data you've worked out to this point. With a starting point like that, we can start playing with the motors before you get them in production, and we can give you additional feedback as to what works and what doesn't.

I'm also interested in the 10 as a class; if I can get 500' from a 13mm A3, and even 200' on a 1/2 A3, then there is potential in this size. What have you been able to realistically predict as far as power in this size package?

Side thought here -- are you considering the 18mm "S" series for anything, or is this a dead size?

About the port burning C engines, we did have a 3/4C19 that was reliable in testing, but the full C was too much to drill. Maybe if it was done in two operations... In any case, it would be closer to a C32 with the same .3 second burn. Peak thrust of 60 N - 13 pounds. That looks like too much warranty work! >400G's in a Sky Hook!

My Triton 3-stage design needs a reliable 18mm booster for the first stage. Right now, it will take a D12 to get it off the pad with enough kick for a 48" rod; I'd like something in the 18mm size for lifting heavier stacks like this, and like the old Centuri T-Bird.

[snaquin]

*still thinking about port burning C's* :D Imagine a Cobra or Ranger on 3xC19's!

..... or a Goliath

Would make for a nice fire and smoke video with 3xC19's in a Goliath fitted with the Oracle camera

The availability of these new Semroc motors will open up many new opportunities! When the new port burners are produced they will be great for getting staged models moving off the rod a little quicker. I'm really interested in clustering and staging them .....

:)

.

[CPMcGraw]

..... or a Goliath

...Or a Hydra-7... :eek:

Maybe that's too much caffine...

[Eagle3]

...Or a Hydra-7... :eek:

Maybe that's too much caffine...

*LOL* I was just thinking of a Hydra 7 too. Better epoxy those fins on!.

[snaquin]

...Or a Hydra-7... :eek:

Maybe that's too much caffine...

*LOL* I was just thinking of a Hydra 7 too. Better epoxy those fins on!.

We'll have to dub that special flight configuration with an appropriate nickname,
like the Semroc Screaming Hydra VII


:)

.

[Mark+3]

RE: 15mm motors I wouldn't discount this size just yet, Carl. This is an intermediate diameter between the standard 18 and the mini 13; I can see possibilities here for "B" class motors that can't be done in 13. Side thought here -- are you considering the 18mm "S" series for anything, or is this a dead size?


Craig, I also would like to see the "S" short series motors. Being 18mm X 45mm a new size tube isn't needed. I see no need to complicate things with another diameter.

Carl, were you planning on releasing the 18 X 45mm when you kitted the Firefly? This size isn't in the family portrait. Will a "B" power load fit this package?

THE 18 X 45mm IS HIGH ON MY WISH LIST.

[Carl@Semroc]

Carl, were you planning on releasing the 18 X 45mm when you kitted the Firefly? This size isn't in the family portrait. Will a "B" power load fit this package?

THE 18 X 45mm IS HIGH ON MY WISH LIST.The family portrait is not complete. I hope to get it updated soon. The S is there. I think only a 3/4B-x will fit in the 1.75" package. But a full B6-0 will fit. Or B14-0S.

[Mark+3]

The S is there. I think only a 3/4B-x will fit in the 1.75" package. But a full B6-0 will fit. Or B14-0S.

Fun stuff, I hope the S makes it onto the first run.

[CPMcGraw]

The family portrait is not complete. I hope to get it updated soon. The S is there. I think only a 3/4B-x will fit in the 1.75" package. But a full B6-0 will fit. Or B14-0S.

Good to hear, as I want to have a FireFly in my collection, too. Maybe even an Estes Midget (or two... Blame Doug S...)... :D

[Carl@Semroc]

Fun stuff, I hope the S makes it onto the first run.It will be a post-production part, so it should be. All the "S" engines I saw were cut from standard engines.

[CPMcGraw]

...I see no need to complicate things with another diameter...

Well, Carl DID mention it... :rolleyes:

...And I actually like the variety in power / weight ratios such a size range can offer. Reducing the mass of the casing while retaining the same (or similar) power can mean extra altitude or extra payload for a given set of designs. That's the real upshot here -- better designs taking advantage of a better variety of motors. We've been motor-starved for so long, we don't really know what it's like to have a smorgasbord to choose from!

[Mark+3]

I twill be a post-production part, so it should be. All the "S" engines I saw were cut from standard engines.

Carl, just as an historical note, I have an original tube of Estes S motors that have the same I.D. as the mini "T" motors with a really thick wall to get to 18mm.

This is NOT the way I would like to see them manufactured, as it adds unnecessary weight.

[Mark+3]

Well, Carl DID mention it... :rolleyes:

...And I actually like the variety in power / weight ratios such a size range can offer. Reducing the mass of the casing while retaining the same (or similar) power can mean extra altitude or extra payload for a given set of designs. That's the real upshot here -- better designs taking advantage of a better variety of motors. We've been motor-starved for so long, we don't really know what it's like to have a smorgasbord to choose from!

I agree, I was just hoping the same thing could be done with "S" size. A lighter weigh package package that utilizes the ST-7/BT-20 we are already using. These could be great for your Schoolyard Sounders.

[James Pierson]

Ok all you rocket experts this is some off the wall motors I have ended up with.

1/2 A6-2 18mm?? about 20 years old that a buddy bought in a box at a garage sale.
What are the good for and are they worth making again?

Also have, but cannot find, some ?Black Diamond? maybe B16-4 18mm :confused: in a black and blue colored two pack of motors. What about these?

James Pierson
NAR# 77907

[Mark+3]

Ok all you rocket experts this is some off the wall motors I have ended up with.

1/2 A6-2 18mm?? about 20 years old that a buddy bought in a box at a garage sale.
What are the good for and are they worth making again?

James Pierson
NAR# 77907

This is the "S" size 18 X 45mm "Short" series motor. See previous posts.

[Ltvscout]

I'm happy to see someone brought up the "Shorty's". I'd love to fly my FireFly as God intended it to be flown. ;-)

Now, regarding motor sizes. I like to be able to fly multi-stage rockets in a smaller field. I'd like to see either the 1/2A6-0 and/or A8-0 boosters come back. Those are nice for three stagers. Use a B14-0 in the first then one of the two listed above in the second. For the third stage, either a 1/2A6-4 or an A8-5. The kids can be wowed with a three stage flight and you can easily get all the parts back.

Another cool motor I thought was the A5 series.

A long burn 18mm in the 114mm length would be neat.

Since Rocketflite still does not seem to be close to coming back, how about making some BP motors with sparky effects? I'm not sure if you were planning on going up to 38mm size with BP or not, but those H BP motors Rocketflite made were pretty slick.

[Ltvscout]

This is the "S" size 18 X 45mm "Short" series motor. See previous posts.
They made the 1/2A6 size in both 45mm and 70mm. I have both in my collection.

[CPMcGraw]

...1/2 A6-2 18mm?? about 20 years old that a buddy bought in a box at a garage sale.
What are the good for and are they worth making again?

Depends on which version you have, James. Estes produced both a standard and a short for a few years (late 1960s into early 1970s). Which do you have?

If they're the "S" version, check out the Estes Star Blazer, K-31, and the Estes Beta, K-45.

Also, check out the original Centuri FireFly, KA-6.

If they're the standard version, that one was called out for the Estes Scout, K-1, Mark and Mark II, K-2 and K-2A, Sky Hook, K-8, Aerobee 300, K-17, and likely many other lightweight designs.

[Ltvscout]

I forgot this one. How about bringing back the old Cox D8 series?

Or, how about showing Estes how to make a D13 that doesn't cato? ;)

[CPMcGraw]

I forgot this one. How about bringing back the old Cox D8 series?

Or, how about showing Estes how to make a D13 that doesn't cato? ;)

Do I correctly understand that the D8 was an 18mm motor?

That could have potential today, like on the Orion!

[Ltvscout]

Do I correctly understand that the D8 was an 18mm motor?
Das ist richtig.

[Carl@Semroc]

Do I correctly understand that the D8 was an 18mm motor?

That could have potential today, like on the Orion!They were standard 18mm x 70mm and only available as D8-0 and D8-3, both almost filled to the top. They were really just HOT C engines with 12.5 N-sec spec and about 11 N-sec tested. They did have a core to get the peak thrust up to about 16-18 N but the average thrust was closer to 7 N rather than 8 N.

[Carl@Semroc]

Carl, just as an historical note, I have an original tube of Estes S motors that have the same I.D. as the mini "T" motors with a really thick wall to get to 18mm.

This is NOT the way I would like to see them manufactured, as it adds unnecessary weight.We are planning the "thick-walled" version as our "R" package. It was the original Estes size tube in the early 1960's. The famous A.8-3 and B.8-4 used that tube.

Retro (R) family



Old# New# Impulse Burn Time
N-sec sec
1/4A.8-0 1/2A5-0R 0.75 0.15
1/4A.8-2 1/2A5-2R 0.75 0.15
1/4A.8-4 1/2A5-4R 0.75 0.15
1/2A.8-0 A4-0R 1.56 0.40
1/2A.8-2 A4-2R 1.56 0.40
1/2A.8-4 A4-4R 1.56 0.40
1/2A.8 A4-5R 1.56 0.40
A.8-0 .6B3-0R 3.12 0.90
A.8-3 .6B3-3R 3.12 0.90
A.8-4 .6B3-4R 3.12 0.90
A.8-5 .6B3-5R 3.12 0.90
B.8-0 B3-0R 4.90 1.40
B.8-2 B3-2R 4.90 1.40
B.8-4 B3-4R 4.90 1.40
B.8-6 B3-6R 4.90 1.40
B3-0 B16-0R 4.90 0.30
B3-5 B16-5R 4.90 0.30
C.8-0 .7C3-0R 6.67 2.00

[James Pierson]

Bad weather here and having internet/computer problems. A power surge took out on of my router sockets. That took me three hours :o to figure it out.


Craig said,
Depends on which version you have, James. Estes produced both a standard and a short for a few years (late 1960s into early 1970s). Which do you have?


Scott said,
They made the 1/2A6 size in both 45mm and 70mm. I have both in my collection.

I have the longer version which to me is 2 3/4 inches long on my American tape measure. As a carpenter I absolutely refuse the metric :confused: system.


James Pierson
NAR# 77907

[Doug Sams]

Make no mistake, I want 1/2A boosters. 1/4 could be fun, too. I read about someone flying a Farside using 1/4A boosters in the first two stages, on a baseball diamond. Sounds like fun, but I'm afraid of the risk - will there be enough buyers to justify 1/4A boosters?

So, here's my take on how to mitigate the risk on this part of of the motor spectrum. Build only T motors (13x45mm). Ship each pack with one 18x70mm empty casing to be used as an adaptor. Pre-print a dashed line on the casing where the user saws it down to 45mm for use as a shorty case. One motor could be used as 13x45, 18x45 or 18x70mm. If users have a hard time making one case last for the entire pack (ie, 3 or 4 motors), then ship one empty case for each motor in the pack.

If a smaller (than T) size is deemed necessary, pre-print a cut line on it. I know 1/4A3-3T and 1/2A3-0T motors can be cut down to 1.25". I've done if before (in what else, a tiny Midget :)

The key here is that, for example, one motor takes the place of three. An A10-0T can also be used as an A10-0S and an A10-0 (~A8-0).

In the case of this particular motor, I'd like to see the thrust tail shortened a bit (in time). It's my understanding the better description of the motor is a 1/2A with extra powder loaded on it to keep it from bursting during the initial thrust spike. That may or may not be true, but the point is that, while a nice spike is good, the low tail is undesirable.

What all this leaves out is 13mm B motors. Perhaps those would use a longer case. I suspect there may be some serious technical challenges with these. MPC had problems. And I think Centuri did, too. And that may explain why Estes never did B-T's.

Now, if a reliable B motor can be built in a 13mm case, then the same adaptor scheme described above may apply. I have a hunch there's a certain minimum aspect ratio (diameter to length) that applies for getting high reliability. IOW, you can't put a big core in a narrow motor. So a 13mm B14 might not be possible, but I'm not an expert.

Anyway, that's my two cents on the 1/4A, 1/2A and A impulse segment of the spectrum.

Regards,
Doug

[Doug Sams]

Good to hear, as I want to have a FireFly in my collection, too. Maybe even an Estes Midget (or two... Blame Doug S...)... :D (vbg) I saw the LDRS video at yesterday's DARS meeting. Seems I made the cut. They had my 4" upscale Midget sustainer on an I285. The rocket and flight looked great; I looked and sounded like my usual hillbilly redneck self :)

Doug

[Initiator001]

Carl,

What market(s) are you planning to go after with your initial motor release?

1) Hobby distributors, dealers, stores

2) Mail-order only (Guys like us)


If #1, then you should make A8, B6 & C6 as they will fit in the 'other' guys rocket kits. You'll
probably have to try and beat them on price to have any hope of getting shelf space. This would not be a concern if Semroc kits are being mass-marketed as you can change your kit instructions to reflect any motor types you produce.

As for #2, I like 'em all! 13mm, 18m, 24mm, etc. As for 15mm, unless there are models that use that size motor, I'd leave it on the drawing board.

At AeroTech, we actually experimented with 15mm motors. We built and fired some for Apogee Components in the early 1990s when we were trying to get a full 'C' motor in a 13mm case. The 15mm seemed like a good compromise but it would have required Apogee to carry a whole set of additional parts for this motor size. Plus, we noticed the casings were pretty close to failing by the end of the burn.

I have one of these burned, 15mm, C20, casings in my collection.

Bob

[Carl@Semroc]

Carl,

What market(s) are you planning to go after with your initial motor release?

1) Hobby distributors, dealers, stores

2) Mail-order only (Guys like us)


If #1, then you should make A8, B6 & C6 as they will fit in the 'other' guys rocket kits. You'll
probably have to try and beat them on price to have any hope of getting shelf space. Since the bulk of our current kits are designed around the A8, B6, and C6, it is not an option to skip them. It is probably true that very few hobby stores will carry specialty engines that Estes or Quest do not offer, with the possible exception of low impulse boosters. We are targeting the online market with the "non-standards" hoping that as they become more mainstream, the more sophisticated hobby stores will add them.
As for #2, I like 'em all! 13mm, 18m, 24mm, etc. As for 15mm, unless there are models that use that size motor, I'd leave it on the drawing board.Our list is more for planning than anything else. We will be freezing the list in a few weeks. It does not mean we will do all of them, but we won't have the paperwork to do any additional ones in the near future.

[Initiator001]

Carl,

Don't forget about California classification for your motors.

I want to fly them! ;)

Bob

[Carl@Semroc]

...will there be enough buyers to justify 1/4A boosters?We don't have the same problem as the larger companies. We already have more items online than they have combined. Are there enough buyers to justify a BNC-10A nose cone? No, but there are enough buyers for a wide selection of parts as long as each one does not require capital investment and large inventories. We look at engines the same way.
What all this leaves out is 13mm B motors. Perhaps those would use a longer case. I suspect there may be some serious technical challenges with these. MPC had problems. And I think Centuri did, too. And that may explain why Estes never did B-T's.

Now, if a reliable B motor can be built in a 13mm case, then the same adaptor scheme described above may apply. I have a hunch there's a certain minimum aspect ratio (diameter to length) that applies for getting high reliability. IOW, you can't put a big core in a narrow motor. So a 13mm B14 might not be possible, but I'm not an expert.The original Estes engines were the same ID (.406") as current 13mm engines. They changed to .5" ID for "manufacturing reliability." Their C.8-0 was a 2.25" slug of BP. It was packed in about 6 different steps. You can only pack one charge a depth of roughly the diameter of the tube, so the .5" ID made for fewer steps, just like shortening the length of the 13mm "T" engines.

[Carl@Semroc]

Carl,

Don't forget about California classification for your motors.

I want to fly them! ;)

BobWe will have that! They can't be contest certified without it either.

[Royatl]

Carl,

Have you ever asked Vern or Ed Brown about the run of mini-motors they made in glassine covered spiral-wound tubes (or did *you* ever try making motors like that?) The ones I have (two A3-0T and one 1/2A3-0T) are marked 6M171 and 6M271. I can't remember for sure, but I think I got them at NARAM-13. Maybe they were test motors that somehow got out in the wild. I think I flew a few of them, but don't remember if I just had boosters or if there were delay ones made. I certainly don't remember the flights or if they had any problems due to the spiral.

Knowing what little I know now about the motor making process, I could see a few problems starting with manufacture (could the tube survive the pressure needed for pressing) to operation (did the pressure on the slurry force propellant into the groove enough that there was no way for the flame front to propagate up it?).

[Carl@Semroc]

Carl,

Have you ever asked Vern or Ed Brown about the run of mini-motors they made in glassine covered spiral-wound tubes (or did *you* ever try making motors like that?) The ones I have (two A3-0T and one 1/2A3-0T) are marked 6M171 and 6M271. I can't remember for sure, but I think I got them at NARAM-13. Maybe they were test motors that somehow got out in the wild. I think I flew a few of them, but don't remember if I just had boosters or if there were delay ones made. I certainly don't remember the flights or if they had any problems due to the spiral.

Knowing what little I know now about the motor making process, I could see a few problems starting with manufacture (could the tube survive the pressure needed for pressing) to operation (did the pressure on the slurry force propellant into the groove enough that there was no way for the flame front to propagate up it?).I never knew that!The Micro-Max II engines are spiral wound fishpaper like coupler tubes. Looked like a great idea for 10mm and 13mm since fishpaper is about eight times stronger than kraft. The walls could be much thinner. Unfortunately, fishpaper burns through much faster and the spirals, unless very tight, form a "fuse" of black powder around the delay. The spiral fills up with black powder so the delay gets bypassed.

I have tried glassine covered spiral tubes for DECAPS. It holds together for nine seconds, being a much better insulator and does not deform as bad as I thought it would under pressure. The difference in cost between high-pressure kraft and the spiral tubes is very small so the parallel kraft is probably better..

[Mark+3]

Checked the 2006 Estes catalog and online, the 1/2A6-2 is still listed.

[Mark+3]

Good input! This is very well received. As I said, the first step is to get a large enough list to get started, get the list approved, then be able to ship samples for testing.


How large of a list?

A full line of 18X70, the "R", "S", and "T" series. Including low power boosters and core burners.

Is there any reason the "R" series could not be made in a thinner walled 13X70mm tube as well as the heavy wall 18mm?

A 13mm (or 18mm) B3-x with a 1.4 sec burn, more fun stuff!

How about the 10mm for the contest folks.

[Carl@Semroc]

How large of a list?As complete as possible for at least the first year.

Is there any reason the "R" series could not be made in a thinner walled 13X70mm tube as well as the heavy wall 18mm?The "R" series is the "Retro" series modeled after the original from the early 60's. Also the early A5 engines used the thicker walls.

A 13mm (or 18mm) B3-x with a 1.4 sec burn, more fun stuff!The 13mm B is there, but the long burn in the 13mm tube may not be feasable.
How about the 10mm for the contest folks.That is definitely in there!

[Mark+3]

The family portrait is not complete. I hope to get it updated soon. The S is there. I think only a 3/4B-x will fit in the 1.75" package. But a full B6-0 will fit. Or B14-0S.

I checked an Estes B6-4 with a depth gauge, 1.2" of headroom above the cap. How much clearance is needed for manufacturing?

[Carl@Semroc]

I checked an Estes B6-4 with a depth gauge, 1.2" of headroom above the cap. How much clearance is needed for manufacturing?The Estes B6-4 is only about 4.3 N-sec. We are trying to get closer to the specified limit. Then it might be close.

[Mark+3]

Are "core burning" and "port burning" the same thing?

[Carl@Semroc]

Are "core burning" and "port burning" the same thing?Yes, in model rocket jargon.

[rocket_james]

Since the bulk of our current kits are designed around the A8, B6, and C6, it is not an option to skip them. It is probably true that very few hobby stores will carry specialty engines that Estes or Quest do not offer, with the possible exception of low impulse boosters. We are targeting the online market with the "non-standards" hoping that as they become more mainstream, the more sophisticated hobby stores will add them.
Our list is more for planning than anything else. We will be freezing the list in a few weeks. It does not mean we will do all of them, but we won't have the paperwork to do any additional ones in the near future.

I'm getting in a little late and really haven't talked a lot with others, but here are my opinions:

I personally would like to see the Semroc motors provide a greater opportunity to fliers. It never made sense to me that Quest repeated the same motors that Estes offered. I seldom buy Quest motors for that reason.

I love the idea of having variable delays that can be attached, 2-9 seconds works great. If that isn't possible, then I can modify my list, below, to add the requested delays:

Specific impulses I'd like to see in 10mm are A5, A8
Specific impulses I'd like to see in 13mm are B3 , B5, B8
Specific impulses I'd like to see in 18mm are B14, C3, C8, D12

I don't know if any of those are feasible, just what I'd like. If the impulse for the specified 10mm and 13mm doesn't work in the smaller size tube, then the next largest tube is fine. If I want to use a smaller motor in a lager tube, I can make an adapter. No need to provide that with the motor.

Thanks for the opportunity to input!
James

[msprague]

I strongly agree with James, above. I too, rarely buy Quest motors (other than MicroMaxx), for the exact reasons listed. I find many of the proposed motors and sizes listed earlier in this thread exciting ... but at least from my point of view, we don't need yaec (yet another Estes clone).

If you can get me motors that fit gaps ... either in size or in power ... then I am very interested.

Personally, I would buy 10 and 15 mm motors and simply convert existing kits or design my own to use them. That said, the more standard sizes would be preferable. I have a couple of 18mm kits converted to 13 mm, just to take advantage of that pesky A10-3 motor.

~ Mike

[Bob Thomas]

Specific impulses I'd like to see in 10mm are A5, A8
Specific impulses I'd like to see in 13mm are B3 , B5, B8
Specific impulses I'd like to see in 18mm are B14, C3, C8, D12


James

I am equally enthusiastic about the above impulse availability. Especially in 18mm. B14-0 is a definite wish. C-5 is noticeable absent, but one sorely missed.

I wish I did not have to go to 24mm mounts just to get the performance I need from my heavier current and future clones, and without wondering if she'll come home! In particular, Skylab, Orion, Redstone, USS America, Deep Space Transport. We need a Super C again. Would that be a reasonable request?

[rocket_james]

I am equally enthusiastic about the above impulse availability. Especially in 18mm. B14-0 is a definite wish. C-5 is noticeable absent, but one sorely missed.

I wish I did not have to go to 24mm mounts just to get the performance I need from my heavier current and future clones, and without wondering if she'll come home! In particular, Skylab, Orion, Redstone, USS America, Deep Space Transport. We need a Super C again. Would that be a reasonable request?
Yep, I really do miss those B14's. If we had to choose one motor in the 18mm line, that's what I would choose. I went with the C3 instead of C5, for differentiation. The C5 is nice, but still pretty close to the C6 - not the same, but close. I went with the C8 and D12 in 18mm for the rockets you noted, plus a few others. ;)
James

[rocket_james]

...we don't need yaec (yet another Estes clone).

If you can get me motors that fit gaps ... either in size or in power ... then I am very interested.

Personally, I would buy 10 and 15 mm motors and simply convert existing kits or design my own to use them. That said, the more standard sizes would be preferable. I have a couple of 18mm kits converted to 13 mm, just to take advantage of that pesky A10-3 motor.

~ Mike
My thoughts, exactly! Motor variability is the biggest link that's missing, IMHO. Motor availability for the high power guys is pretty good, but Estes and Quest left low-power fliers with few options. Maybe folks weren't buying them, I don't know. Possibly, with the increased interest in high power, low power availability waned. Then, as if to pour salt in the wound, even if you bought a bunch of the old motors, the NAR would just come in and decertify them. :confused:
James

[CQBArms]

I would really like to see a wider variety of delays. Or BP "component" motors. D12 with a delay cap and change that can be had in any number of delays. Sort of stack the charge on the motor as needed.
Also a real solid E motor in BP. Not that E9 stuff.

[chanstevens]

Count me in on the bandwagon of 10.5mm fans and some 13mm. I'd really like to see more variety in that area.

18mm seems light a tight/competitive area to be avoided, unless you want to go with longer burn motors, though that's probably not going to have a wide appeal.

In my opinion, the 24mm is pretty open, mainly because Estes has CATO and violent ejection charge issues. I'd love to see a full E, or a slow-burn F that I could use to power gliders. Again, might not be much of a market there, but motor choices for gliders are pretty thin/hard to get.

[Gus]

..Are there enough buyers to justify a BNC-10A nose cone? No, but there are enough buyers for a wide selection of parts as long as each one does not require capital investment and large inventories. We look at engines the same way.
Carl,

Are you saying you will make motors of specific impulses as orders come in?

As for specific impulses, the two of most interest to me so far are the B14s and C3s.

[Carl@Semroc]

Are you saying you will make motors of specific impulses as orders come in?

I meant it more in the sense that when we have the press and dies for 18mm engines, doing the broad spectrum that share the tooling will allow us to do many of the possibilities insteat of limiting it to just the 5-10 "popular" types. We don't have the problems with having too many SKU's that plague the big companies.

[dwmzmm]

I strongly agree with James, above. I too, rarely buy Quest motors (other than MicroMaxx), for the exact reasons listed. I find many of the proposed motors and sizes listed earlier in this thread exciting ... but at least from my point of view, we don't need yaec (yet another Estes clone).

If you can get me motors that fit gaps ... either in size or in power ... then I am very interested.

Personally, I would buy 10 and 15 mm motors and simply convert existing kits or design my own to use them. That said, the more standard sizes would be preferable. I have a couple of 18mm kits converted to 13 mm, just to take advantage of that pesky A10-3 motor.

~ Mike

Quest motors are actually pretty good, with two major exceptions: (1) The soot from the ejection charge is incredibly heavy and, depending on the size/length (and color) of the model, will stain the exterior of the upper portion of the bodytube, and (2) The Quest motor
casing's diameter is a bit less than the standard 18 mm size, and will make for a rather loose
fit if your motor mount uses an engine clip. When I flew my son's Estes Sizzler (the current
version) on a Quest A6-4, the ejection charge simply escaped through the wall of the motor
mount out to the rear with no recovery deployment, causing the Sizzler to lawndart (at first,
I thought the ejection charge simply failed, but discovered otherwise upon removing the
engine from the rocket after recovery). So if you're using an engine clip motor mount with
the Quest motor(s), you'll need to wrap some masking tape to insure this doesn't happen.

[billspad]

I meant it more in the sense that when we have the press and dies for 18mm engines, doing the broad spectrum that share the tooling will allow us to do many of the possibilities insteat of limiting it to just the 5-10 "popular" types. We don't have the problems with having too many SKU's that plague the big companies.


When you get close to putting these into production I know that NAR S & T would appreicate a heads up. All the motors you mention are going to take several days of testing.

[Mark+3]

We don't have the problems with having too many SKU's that plague the big companies.

Carl you mentioned one second delay intervals for DECAPS. Are you considering a full spread
(2 to 8, 3 to 7 or 9) in 2 second steps across the rest of the line?

[ghrocketman]

Here are the motors I'd like to see come out first :
1) A 70mm x 18mm "baby 12-13nsec" D like the old Cox D8-3 and D8-0....those really gave the Mars Lander a good flight seeing as they had about 50% more impulse than the Typical 8nsec Estes C6 and about 30% more impulse than the C5. They worked great in the Estes #1284 Space Shuttle too....I'm almost out of them...down to my last 6.

2) A B14 or B16 port burner in 18mm with -0, 3, 5, and 7 delays....never understood why the B14-6 existed, but thought the -3 should have. For one year Centuri offered an Estes manufactured B8-3 (along with the B8-0, B8-5, and B8-7) which was almost as good....dunno why Estes never offered the B8-3 in their line as THEY made them; Estes only offered the B8-0, 5, and 7.

3) A return of the semi-port burning C5-x 18mm motors

4) Return of the B8-0, 3, 5, and 7

5) A semi-port burning 24mm D motor like the 18mm B8/C5 with about twice the avg. thrust of the Estes D12.....(D24 ?) which would be great as a booster to a "long burn" 18mm long-length "D" like the old AVI D6.1.

Make sure ALL of your new motors produce PLENTY of dense tracking smoke like the Estes/Centuri motors up until the 80's did, not like the lame ones they make now.
Also make sure you get the ejection charges right....seems like 25% of Estes are weak, 50% are just right, and 25% are rocket-destroying "shotgun blasts"...that has caused much more nervousness per flight than I remember flying before I was a BAR....I used to teach rocketry classes to the local Elementary schools and NEVER had a "shotgun" ejection charge through about 1990 (13 years of flying)....have had PLENTY of them since being a BAR....does not seem to follow any particular engine either.

Will you be offering any composites ?
I would REALLY like to see the zero-smoke thrust single use Enerjet F67, F52, and E24 return even if in limited production runs every couple of years....those would be GREAT !
I never got a chance to fly any of those, but did fly several Composite Dynamics Pro-Jets in E and F sizes.

[Bob H]

Depends on which version you have, James. Estes produced both a standard and a short for a few years (late 1960s into early 1970s). Which do you have?

If they're the "S" version, check out the Estes Star Blazer, K-31, and the Estes Beta, K-45.

Also, check out the original Centuri FireFly, KA-6.

If they're the standard version, that one was called out for the Estes Scout, K-1, Mark and Mark II, K-2 and K-2A, Sky Hook, K-8, Aerobee 300, K-17, and likely many other lightweight designs.
I'm surprised that no one mentioned the Estes Astron Sprite. A great rocket for "shorty" motors and with the tumble recovery, a great small field flyer.

I still have my 1967 original and flew it twice this summer on 1/2A6-4S motors.

I always liked the "S" motors and when they were not available any more I glued a 13mm motor mount into my K-31 Star Blazer.

The original Estes Midget was made for "S" motors and was a fun rocket.

[Carl@Semroc]

Bob,
What is the body tube length on your original Sprite?

[dwmzmm]

I still fly my Estes Birdie (also used the "S" motors) with the A10-3T; I just wrap an orange
plastic streamer around the casing with just enough to give a good, snug fit in the BT-20 and
it flies great. With the orange streamer taped on, the engine casing is easy to spot falling
down and on the ground...

[Ltvscout]

Bob,
What is the body tube length on your original Sprite?
Heh, I may have to get another tube from you if the '74 parts catalog was off. ;)

[Carl@Semroc]

Heh, I may have to get another tube from you if the '74 parts catalog was off. ;)Scott, I sent one 2-3/4" and one 2.34" so YOU could sort it out!

[Ltvscout]

Scott, I sent one 2-3/4" and one 2.34" so YOU could sort it out!
Heh, THAT'S what the extra tube was for in the box! I didn't put them next to each other so didn't notice one was longer. Thanks, Carl. :D

Now to wait to hear how long the original Sprite tube actually was and we'll be all set.

I think Kurt Schachner bought the parts for a Sprite from you last Christmas. Kurt, did you build yours yet? It "may" have the wrong length tube.

[Bob H]

Bob,
What is the body tube length on your original Sprite?

And the winner is: 2.75". The hole is .25" and the bottom edge of the hole is 1.25" from the rear.

[Ltvscout]

And the winner is: 2.75". The hole is .25" and the bottom edge of the hole is 1.25" from the rear.
Thank you, Bob!

Now Carl just needs to figure out how to burn a .25" hole in those tubes with his laser. ;)

How does everyone else do it when cloning? Use a hole punch? If so, any problems with disfiguring the tube?

[Eagle3]

And the winner is: 2.75". The hole is .25" and the bottom edge of the hole is 1.25" from the rear.

Phew! Now I don't have to smash my clone to pieces and start over. :rolleyes: :D

[barone]

Thank you, Bob!

Now Carl just needs to figure out how to burn a .25" hole in those tubes with his laser. ;)

How does everyone else do it when cloning? Use a hole punch? If so, any problems with disfiguring the tube?

Scott,

I Just use a hole punch and I've never had a problem disfiguring the tube. Of course, it's got to be large enough for the punch to fit inside..... :rolleyes:

[CPMcGraw]

Carl,

I know that the burn profiles of these motors are different, but are there any general "rules of thumb" that I can follow? Do all of the EBs have a "tail" of constant-thrust following an initial spike? Do the PBs have a generally constant burn, with a simple rise and fall pattern? Is there a "demarcation line" between what Impulse/Time combinations go into the EB category versus the PB category?

This might be useful information for the motor chart...

[CPMcGraw]

Everyone,

Here is the first RSE file based on the motor list from the SEMROC website. The thrust profiles may or may not be correct, but they are probably usable for the present time. As more data is received on these motors, I will correct any power curves that need it.

The following is a recommended procedure for using this file:

1. Create a second copy of your RockSim folder, with all of its files included, and call this file RockSim SVDT. Create a separate icon for your desktop pointing to this new copy of the program.

2. (UPDATED PROCEDURE) Save the attached "SEMROC-NEW" RSE file into the original DATA folder (the original RockSim installation folder). When you run the SVDT copy of RockSim, it will call up the motor files from the original installation and not your new SVDT version.

3. (UPDATED PROCEDURE) To get the SVDT copy to see the new motors, you need to click FILE | Reload Engines. This brings up the available motor files from the original folder. Select the existing SEMROC file(s) in the right-side window and click "REMOVE". Select the "SEMROC-NEW" file from the left-side window and click "ADD". You don't have to remove any of the others unless you just want to use the new SEMROC motors exclusively.

[Mark+3]

Our list is more for planning than anything else. We will be freezing the list in a few weeks. It does not mean we will do all of them, but we won't have the paperwork to do any additional ones in the near future.

Has the list of possibilities for the first round of manufacturing been finalized?

Is the "Family" chart of 1-20-2007 the final?

[Ltvscout]

There hasn't been any news on this front in a long time. Carl, is there any new news you can share with us regarding the possibility of Semroc BP motors?

[Carl@Semroc]

There hasn't been any news on this front in a long time. Carl, is there any new news you can share with us regarding the possibility of Semroc BP motors?Still working away!

We are only able to spend about ten hours a week on it. The first machine is well along. We just got PC boards for the controller populated and debugged. The software/firmware for the controller is almost finished. Then the main program.

Unfortunately, we are going to have to put it aside again for new releases and hobby store push. Got to get $$$ to keep everything else going!

The first machine will do 18mm max diameter and 70mm max length. We are planning on 18mm line first then 10mm, then 13mm.

As an aside, Bill Simon asked if we were doing a "Mabel" style or "Hathaway" style. He explained that an Estes employee named Claude Hathaway "was in his late 60's when he worked at Estes and designed the igniter machine, based on technology that GE used for making miniature lamps. Claude had been a protoge of Steinmetz at GE Labs, and went on to found his own company, Hathaway Instruments, where he designed and built the fault detection gear used in power grids all over the world."

Claude designed an engine machine that sounds like our final design we used in the 60's and our current design. He was not sure if Estes ever built one, but in Bill's opinion, it had many advantages over the multi-station Mable.

[Ltvscout]

Still working away! The first machine will do 18mm max diameter and 70mm max length. We are planning on 18mm line first then 10mm, then 13mm.
Great! I'm glad to hear that there is still a possibility of fresh new BP motors to come.

Unfortunately, we are going to have to put it aside again for new releases and hobby store push.
What's this? New releases? Do tell! ;)

[foose4string]

I figured it was getting time for some new Semroc stuff! Track record has shown a least one new kit about every three months or so, at least that's what my Semroc account reflects. ;) I know there was talk of the Omega, the Centauri, and a Mercury Atlas. Oh wait, that was me, not Carl who said Atlas. :D How's that Orion coming along? ;) :D A guy can dream can't he? :p

Good to hear things are well under way for the motors. Can't wait to grab some of those bad boys. Have there been any talks with other vendors possibly marketing rebadged Semroc motors?

[ghrocketman]

Sounds great that the motors a coming along !!!
Can't wait to get my hands on some port-burning 18mm engines once again !

Speaking of kits, I need to get back to ordering some more Semroc kits....I keep forgetting to send in my order for an Arcas and Space Shuttle !

[James Pierson]

Thanks for the update Carl and since we are on the subject of motors have you had any luck with the orange smoke??

James Pierson
NAR# 77907

[CPMcGraw]

From the "Mainline" threads: ...Or, could Estes have heard something "through the grapevines" that has changed their tactical plan?...

Carl, does Estes know about your "motor madness" yet? Could they be pre-emptively knee-jerking in advance of your getting into production?

[Carl@Semroc]

From the "Mainline" threads:

Carl, does Estes know about your "motor madness" yet? Could they be pre-emptively knee-jerking in advance of your getting into production?I don't think so. We are so small, they would probably not change anything.

I think they are "knee-jerking" more because of the apparent slow-down of the airplane sales (Cox) and apparent slow-down of Wal-Mart sales. I think they were depending on both of those!

[Eagle3]

So what have I missed? Is something going on at Penrose (outside the norm)?

[kurtschachner]

Thank you, Bob!

Now Carl just needs to figure out how to burn a .25" hole in those tubes with his laser. ;)

How does everyone else do it when cloning? Use a hole punch? If so, any problems with disfiguring the tube?

I have a punch that I think you know about. It was the only one I could find that had the required reach. It does flatten the tube somewhat, but it can be pushed back into shape with no permanent damage.

[Ltvscout]

I have a punch that I think you know about. It was the only one I could find that had the required reach. It does flatten the tube somewhat, but it can be pushed back into shape with no permanent damage.
Yup, I remember your punch. I also remember the punch you got from McMaster-Carr that we used for punching out Camroc film disks in your basement in complete darkness. What fun! :D

[Mark II]

I have a punch that I think you know about. It was the only one I could find that had the required reach. It does flatten the tube somewhat, but it can be pushed back into shape with no permanent damage.
Earlier this year, I used a standard hand punch to punch out THREE port holes spaced around the circumference of a Semroc BT-30 when I built my Astron Scout clone. It worked like a charm, with no deformation or undue weakening of the tube.

I have also used the hand punch to cut out gap-staging vents in centering rings. In rings that were too narrow to accomodate the 0.25" hole, I just used the punch to make little semicircular "bites" out of the edges, alternating between the OD and the ID as I went around the edges of each ring. I used this technique to make a gap-staged 24mm motor mount for the booster of my FSI Echo 1 clone (and I also used it to cut the vent holes in the motor tube).

It looks like I'll also be able to use the punch to make the vent holes in the motor tube for my planned Sky Dart clone, too. In making a quick search of plans that include at least one hole-punched tube, I see that in many of these designs (perhaps in all of them), the vent holes are placed close enough to the end of the tube to be within easy reach of a hand punch. :) Which says to me, "Hmmmm..., do ya think...?" ;)

It probably pays to spring for a brand-new punch for this (that's what I did), so that you are using one that has sharp new cutting edges. I think that I paid about $2.50 or thereabouts for my hand punch.

Mark K.

[kurtschachner]

Earlier this year, I used a standard hand punch to punch out THREE port holes spaced around the circumference of a Semroc BT-30 when I built my Astron Scout clone. It worked like a charm, with no deformation or undue weakening of the tube.

Mark K.


The Scout holes are near the forward end of the tube but the one Sprite hole is farther down. That makes it somewhat more difficult, you have to make sure your punch has sufficient throat depth.

[Ltvscout]

The Scout holes are near the forward end of the tube but the one Sprite hole is farther down. That makes it somewhat more difficult, you have to make sure your punch has sufficient throat depth.
I've got all my Sprite parts from Semroc that I ordered last year. One of these days I'll have to meet up with you to punch the hole in the tube.

[kurtschachner]

Yup, I remember your punch. I also remember the punch you got from McMaster-Carr that we used for punching out Camroc film disks in your basement in complete darkness. What fun! :D

There were two problems with cutting Camroc film. The first is that the polyester substrate for the film is incredibly tough, the only way I found to cut it with an arch punch was on a copper backing sheet which was placed directly on the basement floor. An arch punch really isn't the correct tool for cutting film, you need a punch/die combination. I had enough problems finding a 1 9/16" arch punch as it was.

The other problem is that even with this setup you have to hit the punch hard and square. Try doing that in total darkness! You gotta use a small sledge and the risk of hitting your hand is pretty significant. After about 15 good cuts the punch got dull and became useless.

Despite getting some good disks I never flew the Camroc. I did take some static shots but nothing from the air. It makes flying a Cineroc look easy, at least there all you have to do is wind film on the spool. I think you and I did that together as well ;)

[Ltvscout]

The other problem is that even with this setup you have to hit the punch hard and square. Try doing that in total darkness! You gotta use a small sledge and the risk of hitting your hand is pretty significant. After about 15 good cuts the punch got dull and became useless.
Heh, I could've sworn a couple of those swings with the mini-sledge in total darkness did meet with our hands instead of the punch. ;)

Despite getting some good disks I never flew the Camroc. I did take some static shots but nothing from the air. It makes flying a Cineroc look easy, at least there all you have to do is wind film on the spool. I think you and I did that together as well ;)
Yup, we rolled a number of Cineroc cartridges that day as well. Did you ever transfer the Cineroc footage to VHS or DVD? I'd like to get a copy of that if you did or when you do.

[Chas Russell]

Carl,

Amy motor plan updates and/or motor machine progess to report?

Its been quiet here and the crickets are driving me crazy(er)...

Chas

[Carl@Semroc]

Carl,

Amy motor plan updates and/or motor machine progess to report?

Its been quiet here and the crickets are driving me crazy(er)...

ChasStill working on it... I just can't give it more than about 10-20% of my time lately. We were still trying to get five kits out, but there have been many challenges.

Magazine is completed. We are trying to find a day soon to go to SBI and get fingerprints for LEMP.

I have held off on EX application until I could research a little more on AP-butyl rubber.

Only two more air cylinders to order for engine machine.

Printed circuit boards to control engine machine and build static test stands is completed and coded (PIC16C771).

All suppliers for engine parts (tubes, black powder, delay, and ceramic) lined up. Still deciding whether to us plastic or paper mailing tubes for packaging. The old paper tubes like we all used in the 60's is actually more expensive than plastic. I like the view of the engines inside with the plastic.

First engine machine will work with 10mm, 13mm, and 18mm up to 2.75" long, so that will limit the inital offering.

Yeah, I hate those crickets, too. They seem to be telling me that if I work harder, I won't notice them!

[Mark II]

Yeah, I hate those crickets, too. They seem to be telling me that if I work harder, I won't notice them!
Crickets? In December?!? :eek: :D

Glad to hear that things are moving along - it sounds like you are approaching the final stage of preparation. I'm especially interested in seeing those 10mm motors, since I missed out out when Apogee made them (by being AWOL from the hobby). Also, I'm looking forward to the day when I can once again buy"shortie"-style 18mm motors and A-impulse boosters. (I want to fly my retro-repro Firefly and my Midget clone like they were meant to fly! :) :D ). And then, of course, I am also still going to bed on many cold winter nights with visions of adjustable delays dancing in my head...

AP-butyl rubber propellant, huh? Interesting...

I say to go with the plastic mailing tubes (we're going to need payload sections! :D ).

Looking forward to seeing those new kits!

Mark K.

[CPMcGraw]

...I say to go with the plastic mailing tubes (we're going to need payload sections! :D )...

That's a thought...

Mailing tubes from convienient lengths of CPT-10...:rolleyes:

[Ltvscout]

Carl,

Here's something I don't recall us discussing...

Does Semroc have its own igniter design that you plan on using? If so, can you share any info about the igniters with us?

[Carl@Semroc]

That's a thought...

Mailing tubes from convienient lengths of CPT-10...:rolleyes:Yeah... with one end cap shaped like a nose cone and the other shaped like a nose block! I had not thought of that.

[Carl@Semroc]

Carl,

Here's something I don't recall us discussing...

Does Semroc have its own igniter design that you plan on using? If so, can you share any info about the igniters with us?We always used nichrome wire held in place with balsa strips. I liked the idea that the plugs would not litter but be easier than the tissue balls to use. Our final design used a small bit of pyrogen on the ends of the balsa strips. Our new igniters will probably be nichrome, plated with copper and dipped in a flammable insulator held in place with balsa strips.

[foose4string]

Yeah... with one end cap shaped like a nose cone and the other shaped like a nose block! I had not thought of that.


Now, there's an added incentive to buy Semroc motors!

[barone]

Now, there's an added incentive to buy Semroc motors!
As if any would be needed..... :D

[Ltvscout]

We always used nichrome wire held in place with balsa strips. I liked the idea that the plugs would not litter but be easier than the tissue balls to use. Our final design used a small bit of pyrogen on the ends of the balsa strips. Our new igniters will probably be nichrome, plated with copper and dipped in a flammable insulator held in place with balsa strips.
Thanks for the insight, Carl.

[foose4string]

As if any would be needed..... :D

Not for me, that's for sure. But if people were getting half a rocket with their motor purchases, that sure would sweeten the deal! ;) :D

[barone]

Not for me, that's for sure. But if people were getting half a rocket with their motor purchases, that sure would sweeten the deal! ;) :D
LOL.....buy some motors and get a free almost rocket.... ;)

[foose4string]

"Parts is parts." :) Maybe Carl was joking, I don't know. Sounded good though. ;)

[Mark II]

"Parts is parts." :) Maybe Carl was joking, I don't know. Sounded good though. ;)
Building rockets out of motor mailing tubes is almost as old as the hobby itself. Estes actually sold a few different nose cones that fit their mailing tubes, and published some designs for that tubing in their design book. In the design book, the mailing tubing is designated as BT-40.

Semroc sells BT-40, along with some nose cones for it, and even a balsa block. It is sturdy, heavy-walled stuff (I have some). Incidentally, BT-30 is a perfect slip fit into BT-40, and can be used as a tube coupler.

Mark K.

ADDENDUM: BT-40 is also a perfect intermediate size between ST-7 and ST-8. - MK

[Carl@Semroc]

Still laughing!

A few SVDT members saw a prototype of the engine tube with engine labeling at NARAM last summer. The tube is a 9" length of CPT-8 with two flat removable/replaceable clear end caps. The nose cone and coupler idea would have been nice, but costs would be way too high. The end caps are about 3 cents each.

[Mark II]

Still laughing!

A few SVDT members saw a prototype of the engine tube with engine labeling at NARAM last summer. The tube is a 9" length of CPT-8 with two flat removable/replaceable clear end caps. The nose cone and coupler idea would have been nice, but costs would be way too high. The end caps are about 3 cents each.
LOL! I didn't think you were serious about the nose block and nose cone idea. Oh well, we'll just have to purchase those separately! :D

Mark K.

[ghrocketman]

Hey Carl,
Any progress on the Semroc motors ? :D

[Carl@Semroc]

Hey Carl,
Any progress on the Semroc motors ? :DSlowly. It is mixed in with the other 100 high priority items we have to get done before yesterday. :o

I am working on a final spreadsheet for EX-number application. This will cover the family for at least the first year of production. I hope to post it here in the near future.

[ghrocketman]

Even SLOW progress is good !
You are one of very few that actually responds to the needs/wants of real rocket buliders in the LPR/MPR arena.


So you have a list of 100 high priority items as well....sounds like my job as an Automotive Electrical Engineer.... :p
EVERYTHING that gets sent my way at work seems to be of HIGH priority and every request seems to have a delivery date of a week before LAST Tuesday..... :p

[foose4string]

That motor discussion the Doctor started is garnering a lot of attention and discussion. Most activity I've seen around here in a while. Loads of great input there. Getting these motors out takes Semroc to a whole new level....can't wait. :D The "Semroc C5".....hmmm ...kinda has a ring to it...don't it? :D

[CPMcGraw]

That motor discussion the Doctor started is garnering a lot of attention and discussion. Most activity I've seen around here in a while. Loads of great input there. Getting these motors out takes Semroc to a whole new level....can't wait. :D The "Semroc C5".....hmmm ...kinda has a ring to it...don't it? :D

Yeah, and it's going to be so much fun listening to the reaction when Carl finally "spills the beans" about all these new motors...:D

[Carl@Semroc]

Yeah, and it's going to be so much fun listening to the reaction when Carl finally "spills the beans" about all these new motors...:DSeveral people have "warned" us that there might be some at eight-one-two-four-zero....

[CPMcGraw]

Several people have "warned" us that there might be some at eight-one-two-four-zero....

No doubt. Might raise an eyebrow at eight-one-one-four-seven as well.

[foose4string]

Think we'll need to hire Carl a body guard? :D

[Ltvscout]

You guys made me go to www.usps.gov to verify what I figured those numbers were. ;)

[Ltvscout]

Carl,

I don't recall if this was discussed earlier in the motor thread or not. Are you working on a delay formula that will offer a denser smoke trail than what is currently offered by other BP motor mfg's?

After things get rolling, have you given any thought about possibly doing some special effects type motors? Something like what the Silver Streaks gave us?

[Carl@Semroc]

Carl,

I don't recall if this was discussed earlier in the motor thread or not. Are you working on a delay formula that will offer a denser smoke trail than what is currently offered by other BP motor mfg's?

After things get rolling, have you given any thought about possibly doing some special effects type motors? Something like what the Silver Streaks gave us?Smoke is much more complex. I am not going to dwell on it as much as I have been. Orange (yellow,red) is too messy and unreliable. Mods to the propellant means much more complex EX testing.

So, at least initially, grey smoke and BP propellant.

[Ltvscout]

Smoke is much more complex. I am not going to dwell on it as much as I have been. Orange (yellow,red) is too messy and unreliable. Mods to the propellant means much more complex EX testing.

So, at least initially, grey smoke and BP propellant.
I wasn't looking for a different color smoke, just more of it. ;)

[Gus]

Carl,

I really appreciate the risks you're taking to produce motors.

So here is my commitment to you.

The day you start producing motors, I will fly only Semroc motors of any type you produce.

Period.

Put me on the list for ten 3-packs of each type, the first day they are offered for sale.

The first box of motors that Sheryl sends out I want to be addressed to me.

I don't care what they cost.

And I will personally sponsor "Semroc Day" at my local club, so everybody has a chance to fly the new motors just as soon as they are available. (You hear that Buzz, your first day of Semrocs are on me!)

On the day I receive my first Semroc motors, my old motors of the same type will go into my collectables pile.

From that day on, I will fly Semroc.

All I ask is that you make a success of this (and that I go on the early list for an "I Fly Semroc" t-shirt and launch box sticker). ;)

There are many of us who REALLY want you to succeed at this.

So I personally will do whatever I can to see that happen.


Steve

[foose4string]

You guys made me go to www.usps.gov to verify what I figured those numbers were. ;)


Flew completely over my head, I had to ask Craig.

Gus, that's the spirit! I at least want to buy and test the product before I make that kind of statement. But really, given Semroc's track record, it's safe to assume the motors will be top notch.

There's only a few suggestions over there that I don't agree with , but for the most part, everything I'm seeing sounds good. I don't think B14's and similar are worth the risk. I thought the colored smoke would be a good way to make the motors stand out from the competition, but I'd rather see some reliable, safe, motors be produced above all. Keeping it simple in the beginning makes good sense. Just getting these in people hands and creating a buzz will be challenging enough, but with the loyal following Semroc has cultivated, I think we've(this is a team effort with some kick ass owners) got a good shot at this!

[ghrocketman]

B14's and the like are EXACTLY what I want from a new motor manufacturer and am willing to pay for them....frankly I'd be glad to buy B6-4's from Semroc instead of that unresponsive to customers company that Estes has become.

[Royatl]

Not to be a spoil sport or a stick in the mud, but I really wish the hobby would get away from the emphasis on "effects" motors (though if the effect is simply part of the improvement of the motor's characteristics, I can't complain). White lightning is nice, blue thunder -- could take it or leave it, smoky motors are ok if that's the only way to get a slower burning propellant (though I doubt it!). To me, sparky motors are cool once, after that, just go burn some fireworks.

I'd rather have varied and reliable thrust characteristics.

[foose4string]

GH, from what I've been reading, it sounds like the B14 adds an addtional risk to the manufacturing process. I'm more concerned with safety issues for Carl and Co., over my need for thrust options. If Carl thinks it can be made safely, then by all means...crank 'em out! I've never used a motor that size, so I suppose I don't know what I'm missing. Was the B8 be a suitable replacement?

[Royatl]

The B8 was OK, as was it's brother the C5, but I really couldn't tell much of a difference. Other people swear by them, however.

In 1972-73, Trip Barber tested a number of B14s and B6's on MIT's test stand (one of fairly modern design, though it recorded onto pen/paper instead of to a computer), and there wasn't much difference between the two types! The B14s did have twice the max thrust, but it must've been a very quick spike, as the average thrust remained around 6 newtons. Earlier English unit Estes B3's did measure closer to spec, having a max thrust almost two pounds more than the 14s, with an average thrust of 15 newtons. I think the difference may have been the increased grain diameter of the newer motors (0.5" vs 0.41") didn't allow as deep a core as the old B3s.

[Carl@Semroc]

So here is my commitment to you....
SteveAnd our commitment to you is that we will not offer them for sale unless you feel the same way AFTER we have them.

Thanks for the confidence in us. It goes a long ways.

[Carl@Semroc]

Not to be a spoil sport or a stick in the mud, but I really wish the hobby would get away from the emphasis on "effects" motors.We spent a lot of time in the late 60's working on a dense white smoke or bright orange smoke. The purpose was to provide a "signature", so everyone would know just after launch that the rocket was powered by Semroc. We would still like that, but a reliable delay is the first priority. Our white smoke had the drawback that the volatiles would evaporate over time, shortening the delay. The orange smoke is really messy and when it is bright and looks the best, has the very nasty habit of going out!

My goal is to eventually get back to the Estes smoke of the late 60's and early 70's, dense dark yellow with very low "cookoff" after delay burnthrough. And that super sulphurous smell that mixes with Johnson's Baby Powder and makes a unique smell that is so 60's. Now THAT is an effect! :D

[Carl@Semroc]

GH, from what I've been reading, it sounds like the B14 adds an addtional risk to the manufacturing process. I'm more concerned with safety issues for Carl and Co., over my need for thrust options. If Carl thinks it can be made safely, then by all means...crank 'em out! I've never used a motor that size, so I suppose I don't know what I'm missing. Was the B8 be a suitable replacement?It will be safe. When you get older, you take fewer chances. We will drill the B8 as well. Our machine is not like Mabel.

[A Fish Named Wallyum]

To me, sparky motors are cool once, after that, just go burn some fireworks.


You forgot to say "...after that, stomp out the brush fire, THEN just go burn some fireworks." :rolleyes:

[barone]

......... And that super sulphurous smell that mixes with Johnson's Baby Powder and makes a unique smell that is so 60's. Now THAT is an effect! :D
Aaaahhhhhh! The good old days ;)

[Eagle3]

.... And that super sulphurous smell that mixes with Johnson's Baby Powder and makes a unique smell that is so 60's. Now THAT is an effect! :D

You just described my hobby room *stirs the box of burnt casings* Ahhhhhhhh..... ;)

[Ltvscout]

You just described my hobby room *stirs the box of burnt casings* Ahhhhhhhh..... ;)
Heh, ya know, when I got back into the hobby in '98 the first thing I did after my first launch was to sniff the spent motor casing. Smells really do bring back memories!

[foose4string]

I love the smell too. I noticed the smell had changed slightly from what I remembered as a kid. A burnt rocket motor is a smell you never forget. Did they change the formula at some point which made the motors smell differently, or am I just imagining things?

[Ltvscout]

I love the smell too. I noticed the smell had changed slightly from what I remembered as a kid. A burnt rocket motor is a smell you never forget. Did they change the formula at some point which made the motors smell differently, or am I just imagining things?
Like Carl was saying, I believe the delay train used to have a higher sulfur content then what it does now.

[foose4string]

Ah, I missed where he said that. That would explain it. I do remember a more sulphurous smell compared to the newer ones. That was something that hit me bigtime after getting into the hobby again a few years ago. Funny how distinct smells will get stuck in your brain like that.

[Eagle3]

Heh, ya know, when I got back into the hobby in '98 the first thing I did after my first launch was to sniff the spent motor casing. Smells really do bring back memories!

*LOL* No kidding. When I need a pick me up I grab a old casing (I really do keep a box of spent ones in the room) and take a whiff. Good times. :p

[kurtschachner]

Heh, ya know, when I got back into the hobby in '98 the first thing I did after my first launch was to sniff the spent motor casing. Smells really do bring back memories!

Once back in college I read an article about what senses made the deepest impression in the brain. It turned out that olfactory was #1. You remember smells longer than anything else and they have the ability to conjure up memories more strongly than any other sense.

The other day there was some show on TV about fireworks companies and the families that run them. There were a bunch of brothers from one family standing around and the reporter asked what it was they enjoyed most about the business and what it was that kept them there. The answer came almost immediately and in unison from them all – “the smell of burnt black powder!”

[Carl@Semroc]

We always did static testing behind the old manufacturing building. The smell was potent after going through several batches of engines. The young ladies, mostly, avoided it because of the smell. Their descriptions were graphic. My canned response was that "it smells like money to me." I think they preferred checks.

[ghrocketman]

The B8 and C5 series were decent motors in that they could lift a good bit more than the run of the mill B6 or C6 motors, but they were no B14/original B3.
I have quite a few B8, C5 and B14 motors in my stash and still fly a few of them each year.
Needless to say I fly on my own private land and am not the least concerned whether their "certification" has lapsed.

Probably at least 25-30% of the BP SU motors I regularly fly have been de-certed....never had a CATO either with any of them except the following:
Estes C5-3's from the "bad" lot before I knew it was bad
Estes E15-x, about 30% CATO rate for everything but the E15-P, which has NEVER CATOed for me to this day & I still fly the "P" variety, but nothing else.
FSI E60-x; over 75% CATOs
FSI F100-x; at least 30% CATOs

The majority of the B14's I have are of the B14-0 variety.
I am down to around only 3-4 packs of B14-5's and 7's.
I think I only have 2-3 loose B14-6's left

[Rocket Doctor]

As we can all see, the thread "Motor matters" has generated a lot of discussion.

When the estes forum was up and running, we also discussed motors there. From the input that we received on the forum, I passed this information along to Barry and Joe Sieberlich, their engine production manager, also, Mike Dorffler got involved.

The type of motors were discussed, and, the B14 was shot down immediately. Also requested was the C5-3, mini boosters and lower power boosters. Right now, you can purchase an educators bulk b pack that included the B6-0, but, Estes is way too stubborn to put those in three packs for whatever reason.

I was told that a lot of motors were dropped because of the units sold didn't make it worth them to produce them anymore.

Estes deals in voulume and $$$, if it's not bringing in the bucks, it's dropped.

Also discussed was bulk packs of "D" motors being sold in walMart, which, Estes will not do either.

As I have mentioned previously under "Motor matters" we need competiton, Estes is the "bully" on the block, they know they don't have competition form anyone (Quest is not a threat as far as motors go) and they feel, if your going to fly rockets, you have to buy your motors from us.

The prices have jumped up again, way, way too high in my opinion.

[Ltvscout]

Carl,

I was looking at the Estes '61 catalog. What can you tell me about the B.16-x motors they made then?

http://www.ninfinger.org/%7Esven/rockets/catalogs/estes261/261est10.jpg

P.S. - I posted here to also see how things are coming along on the motor making front. :D

[Carl@Semroc]

Carl,

I was looking at the Estes '61 catalog. What can you tell me about the B.16-x motors they made then?

http://www.ninfinger.org/%7Esven/rockets/catalogs/estes261/261est10.jpg

P.S. - I posted here to also see how things are coming along on the motor making front. :DThey were the core burners using Mabel I. They had the .406" ID casing and a long, drilled port. They were stated to be a 16 lb average thrust as opposed to the .8 lb of the end burner. This would have made them D impulse by todays standards!

It was difficult using early static test stands to test a core burner that created not much more than a spike. They were later designated B3-x (pre-metric) which signified 3 lbs of average thrust. After the change to metric (thrust in newtons, etc.) and the change to Mabel II with .5" ID, they were replaced by the B14-x (which was about 3 lbs average thrust also.)

We are still working with the various governmental agencies AND trying to keep everything else spinning!

[Ltvscout]

Thanks for the info on the B.16.