To burn or not to burn

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kclo4

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...that is the question.

So I was at a launch today and was checking with folks on whether or not I could fly some very old motors. We fly research rules so just wanted to check as they are most certainly not currently certified. Can't even find the things on thrust curve.
Anyway, one of the guys insists I should not fly them. I protested insisting that they should be used for their original purpose.

The motors in question:

Rocket Dyne Systems 40E25-4, and a 40E50-8. Yeah.

They are composite, so ignition could be dicey, but if I could get them lit, they should run just fine.

What say you all? Condemn them to somebody's dusty motor collection full of memberberries for a couple hamburgers worth of green, or let the newtons flow and bring joy to those around?
 
kclo4 said:
...that is the question.

So I was at a launch today and was checking with folks on whether or not I could fly some very old motors. We fly research rules so just wanted to check as they are most certainly not currently certified. Can't even find the things on thrust curve.
Anyway, one of the guys insists I should not fly them. I protested insisting that they should be used for their original purpose.

The motors in question:

Rocket Dyne Systems 40E25-4, and a 40E50-8. Yeah.

They are composite, so ignition could be dicey, but if I could get them lit, they should run just fine.

What say you all? Condemn them to somebody's dusty motor collection full of memberberries for a couple hamburgers worth of green, or let the newtons flow and bring joy to those around?
Click to expand...

Either put em in a holder on the ground and light em' or put em' in a rocket and light em', we frequently have individuals to "demo" burns of old motors by putting burying them in the dirt up to the nozzle and lighting them off, its a chance for some folks to see motors they will likely never have the chance to see again, and yes some do CATO thats whe we do it out at the HPR pads.
 
If you fill out paperwork with NAR, you can fly decertified motors as long as it was an OOP decertification, not a safety one, with them. The old motor firing is to gauge how performance changes as motors age.

I don't know for Tripoli, but if it was decertified for OOP reasons, you should be able to as well.
 
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If you fly with a NAR section then contact the chairman of the Sport Services committee (Steve Lubliner) in writing (E-mail works) about the OOP motors you wish to fly. He can be somewhat slow to respond so give yourself plenty of lead time.

I have done this several times over the past 4-5 years, the last time was for NARAM-58 this past Summer. No problem getting an approval. Just follow all the guidelines for flying the motors.
 
I am not really worried about whether it's ok per rules, I would just as soon not fly it at a club launch if I had to.
Was more worried about whether they should be burned at all. Some folks seem to think they should be kept as collectors items. I don't know how rare they really are, or if it even matters.

It's interesting in that I literally cannot find reference to them anywhere. Google has zero hits relating to the name and the motor code. I found a listing of larger RDS motors as well as some talk of the larger kits. The oldest web page on the wayback machine is from 2008 and it looks like RDS stopped motor production long before that. I think I was given these motors around 2000-2002 and I think they were old then.
 
Keep in mind also, that various old composite motors tend to have the delay trains burn slower, so the ejection may be very late. Or not even eject at all.

Also of course, if they were stored well in a dry place or stored very badly in a humid area, especially a garage or undeveloped basement. Heck, I even had some reloads that were stored at home, air conditioned, but I had opened the bag years before and the natural high humidity in Alabama did its thing to make the grains swell up to the point I could not use them. I had identical packs bought at the same time that had not been opened, which did not have this problem.
 
georgegassaway said:
Keep in mind also, that various old composite motors tend to have the delay trains burn slower, so the ejection may be very late. Or not even eject at all.

Also of course, if they were stored well in a dry place or stored very badly in a humid area, especially a garage or undeveloped basement. Heck, I even had some reloads that were stored at home, air conditioned, but I had opened the bag years before and the natural high humidity in Alabama did its thing to make the grains swell up to the point I could not use them. I had identical packs bought at the same time that had not been opened, which did not have this problem.
Click to expand...

So then problably test launch one in a rocket where the ejection doesn't matter and is vented, like a spool spinner or saucer.
 
kclo4 said:
I am not really worried about whether it's ok per rules, I would just as soon not fly it at a club launch if I had to.
Was more worried about whether they should be burned at all. Some folks seem to think they should be kept as collectors items. I don't know how rare they really are, or if it even matters.

It's interesting in that I literally cannot find reference to them anywhere. Google has zero hits relating to the name and the motor code. I found a listing of larger RDS motors as well as some talk of the larger kits. The oldest web page on the wayback machine is from 2008 and it looks like RDS stopped motor production long before that. I think I was given these motors around 2000-2002 and I think they were old then.
Click to expand...

Keep them then. If it's a matter of whether it's worth collecting, stash it up for a couple of decades and YES!
If people collect OOP kits, why not OOP motors?
 
Alright! Here are some pics.

So it looks like RDS was releasing motors and getting them certified around 1998. One of the local Albuquerque club guys, now deceased, was a vendor at the time as was getting either demo motors or production motors from ODI. There was stuff going on at the LDRS's at the time with demos and such.

ODI was a distributor or related to the manufacture, but I can't find any details.
I think the manufacture is some of the same people that have manufactured for aerotech. The construction looks pretty similar. Epoxy, fiber composite tubes, phenolic nozzles, etc.

RDS was pretty prominent for a while but changed hands a number of times for various reasons and I am sure the rocket motor product fell off. I am not even sure if these ever got certified.

Anyway, I am pretty sure I can get the scoop from the guy who gave them to me. The treasure hunt is kind of fun though.



1114160715.jpg1114160658a.jpg1114160658.jpg
 
Very cool and thank you for sharing, $7 a piece and no shoulder. Interesting.

The nozzle looks a little rough in one of them or at least gray.

I say fly em!
 
I think all the econojet motors don't have a thrust ring either. Not sure if the newer DMS motors do or not.

The nozzles are pretty smooth, that's just dust. I was trying to think of a tool small enough to try to rough up the propellant grain inside the motor without messing up the nozzle throat.
 
Paperclip, 1/8 inch of one end of a straightened paper clip into an approx. 30 degree hook. Or just push the straightened clip towards the wall of the grain.

(lightly, or course. Not shoved into the propellant, just enough to scratch up the outer coating.

Or superglue some sandpaper onto the end of the paperclip.
 
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Those motors look like older AeroTech single-use motors that were made for another company to label and resell (NCR, Public Missiles, Rocket Vision/Impulse Aerospace).

Phenolic case with bonded nozzle and paper cap.
 
Initiator001 said:
Those motors look like older AeroTech single-use motors that were made for another company to label and resell (NCR, Public Missiles, Rocket Vision/Impulse Aerospace).

Phenolic case with bonded nozzle and paper cap.
Click to expand...

I beg to differ, based on the end cap info: MFG BY DPT LLC IN USA, I'd say some incarnation of the crazy world of Jerry Irvine/U.S. Rockets.

View attachment 305351

https://v-serv.com/usr/motors.htm

I'd like to find out what the NAR would say about burning them under the OOP motor umbrella.


[edit] I think you nailed it first dhbarr !
 
Yeah, I think you got it samb - those look like USR and I know that Mike Gillette and Jerry I had some things cooking.
 
fly them! Go to a Tripoli launch and if you're L2 it's all good.
(if you don't want to use them, I volunteer to fly, or, ahh, dispose them
 
I collect various composites and fly those that I have many of. The inability to ship makes finding a buyer tougher than finding a kit collector. Might be best to arrange sale at a regional launch nearby - no clue on the value or if they are a USR. Some a truly collectable, others rare and kind of neat, others are simply old and unreliable as flyers.

I buy vintage at a discount because if I do fly them, so work perfect, some never lit after burning 4-5 igniters, some chuff and rod / rail hop before finally kicking in (very entertaining). Delays are often off or no ejection. So as a flyer they are worth much less than a new motor IMO. Options vary, but this is my experience. Lots of fun in saucers, or rockets of little value to you (maybe some cheap electronic deployment).

If poorly stored, igniters may not fit in the propellant core due to grain swelling. I have recently been gifted reloads than have muffin top grains on some of the bates grains, C-Slots that opened up like a PacMan when he died. If this was in a casing, it would seal the C-Slot and require opening it through the nozzle (drill, small pipe cleaning brush, bamboo skewer or whatever).

Some are perfect and no issue. Inspect them to the best of your ability, fly them in something you are not to attached to and enjoy the result. Regardless of wind direction, aim away from any people / vehicles in case of a lawn dart.

My 2 cents.
 
This is definitely a USR E25 and E50 still listed under motors.

I tried finding the rocket dyne v-serv page but didn't think to look through JI's current list of motors.

Might be fun to burn them, dunno how reliable those particular USR motors are. Don't have anything small enough capable of electronic backup.
 
kclo4 said:
This is definitely a USR E25 and E50 still listed under motors.

I tried finding the rocket dyne v-serv page but didn't think to look through JI's current list of motors.

Might be fun to burn them, dunno how reliable those particular USR motors are. Don't have anything small enough capable of electronic backup.
Click to expand...

Not sure on the current vintage line of USR. The old Fire starters were awesome to see. Overall they motors were cheaper, but more likely to CATO or lawn dart than the Vulcan and Aerotech of the time. This is based on observance at some of the East coast launches I attended as a kid (no statistical data). USR did have its loyal followers. I however new to watch as there was a good chance of something exciting happening.

Build a small, cheap rocket - don't focus too much on making it pretty and get them a try.
 
https://v-serv.com/usr/motors/e25.html
E25-4,8
0.938 x 2.75"
5.30
1.7
40 Ns
21 g.
B
10.95

https://v-serv.com/usr/motors/e50.html
E50-4,8,12
0.938 x 2.75"
11.20
0.8
40 Ns
21 g.
B
10.95

Take those numbers for what they are ; I have a hard time believing those figures work exactly, and would expect them not to hit those performance numbers even if they do light and don't asplode.
 
Last edited:
kclo4 said:
This is definitely a USR E25 and E50 still listed under motors.

I tried finding the rocket dyne v-serv page but didn't think to look through JI's current list of motors.

Might be fun to burn them, dunno how reliable those particular USR motors are. Don't have anything small enough capable of electronic backup.
Click to expand...

I wouldn't put alot of resources into the airframe for the test platform. How about an Art Applewhite free saucer. https://www.artapplewhite.com/free.html
 

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