EX Motor Questions (no formulation data please)

Before I start:

Please do not post anything that could get any of us in trouble. No formulas, no ingredients, nothing.

With that being said, the questions are simple. I could probably locate this info on the web, but I didn't have any success in my searches.

Very soon I'm going to be getting into EX. I've already started working on a basic understanding. As I won't have my L2 until at least February, I cannot gain access to the research forum. Nothing I'm asking will break the law.

I know you can use Loki, AMW, and Gorilla motors for EX loads. Are there any other motors that can be used?

Loki has reusable nozzles. Do any of the others offer this,

My experience with RMS is strictly Aerotech. There are washers and o-rings in them. Do the snap ring motors use these? Are they some special order item or can they be obtained normally?

I've seen pictures of the mixing being done in kitchen aid mixers. I've heard tale of a shaking table. I know there's a mandrel used to create the core. Is there any other equipment required that I could start purchasing ahead of time?

I know they are packed into liners then cut to length. Is there two liners like with AT motors? One the grains are packed and formed in and a second one to line the motor case?

That's it. If there's anything else that I need to know ahead of time, fill me in. Just please don't get us in trouble.

ADMIN: By everything I have read and checked, these questions are not an issue from any legal standpoint. If you do not agree, feel free to delete. I won't be offended. I just want to be prepared as much as I legally can.

I think you're OK unless you post formulas.

Most snap ring motors use reusable nozzles. They are generally considered to be the best option for research/EX. A great way to start are Dan's 29mm cases. https://www.etsy.com/shop/EasyResearchRocketry

They use o-rings. The manufacturers generally post the sizes you need. I just buy packs of 100 from McMaster, and recently Amazon. You can get parts for Aerotech from https://www.rocketmotorparts.com. Note that Aerotech is generally considered not to be a good choice for starting out in EX.

You also need casting and liner tubes. There are a few sources for those depending on the size and manufacturer of the cases.

I like Kitchen Aid mixers. I started hand mixing, and it does work. But larger batches can really tire your arms out. If you watch classified ads, you can usually get them for half the new cost. Another nice thing to have is a vacuum pump. It's not required, but I was surprised at how much air I was able to get out with one.

you can use Aerotech and CTI case for Research loads too.
Snap ring motors use a (metal) nozzle washers and o-rings. You can purchase them directly from the motor vendors.
There's a bunch of stuff you'll need to mix and make motors. It would be best to find a local mentor top help you figure out what you have and what you'll need to get.

A good start might be getting a book called..
Experimental Composite Propellant
by P'rfesser Terry McCreary Ph.D. Murray State University, Kentucky

Tony

And listen to Tony. That guy knows his stuff.

tfish said:

A good start might be getting a book called..
Experimental Composite Propellant
by P'rfesser Terry McCreary Ph.D. Murray State University, Kentucky

Tony

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Good suggestion Tony.

Here is the link... https://www.compositepropellantbook.com/

The requirements for access to the research forum do not include L2 status.

Ok, you guys are awesome. Thank you for sharing.

I do have a potential mentor. I've always felt more comfortable asking things in forums. Here you can choose to answer or not. Asking questions in person really puts someone on the spot.

A recent search turned up posts on another forum that actually has formulas. Can't that get you in trouble with Homeland Security? But I will admit it explained a lot. Not enough, but a lot.

Chemistry is easy. Technique is the part I'm most concerned about. And locating the accessories will be fun lol. Especially the mandrels for the cores. Unless I just use a round core. But that's just for bates and moon grains right?

Steve Shannon said:

The requirements for access to the research forum do not include L2 status.

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Good catch Steve.

https://www.rocketryforum.com/showthread.php?17943-Research-Forum-Access

You don't have to be level 2 to access the Experimental sub-forum. Just click on the sub-forum and it will tell you what you need to do to gain access. I sent in my request and was granted access in a day or so. TRA level 1.

Mike Fisher over at Binder Design also does Fisher Research hardware. Snap ring cases, reusable nozzles, O-rings..all that jazz. 38mm 2 grain through 16 grain. Think that would be about 120 through 960. He may even have some fancy colors he can do em in, don't know for sure.

Mikey D

Worsaer said:

Good catch Steve.

https://www.rocketryforum.com/showthread.php?17943-Research-Forum-Access

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That's interesting. You have to be TRA L2 to do research motors. If you don't have to be L2, why does HPR cert matter at all? Not arguing. Just don't get it. I'll send my request immediately. Thanks for sharing that.

as I understand it, you need to be L2 to fly ex motors at a TRA research launch, forum access is entirely different.
Rex

I also just recently found out the EX forums only require L1. I should read the rules more carefully.

Dan's ERR cases are a great starting point. Cut down CTI spacer plus AT FSD lets you run anyone's HP grains.

Grab some of his 3D printed parts, a long 29mm MMT, etc.... I'm not sure it's possible to do EX any more cost-effectively.

Forum access aside- I would recommend to start with a small case (G or H motors), and have a somewhat disposable rocket that you can test fly things in for their first flight test. Please note that most EX motors do not have ejection charges, so it would have to be electronic deploy. I use a wildman interceptor 54 with a nose cone av bay. I have an eggtimer quark in the av bay to pop the chute at apogee. Not a large amount of cost if something were to go kafloopy, and it's easy to get ready at the range.

Some good recommendations on cases above- I would also recommend the 38mm Loki cases. Also watch the for sale section of the forum- you can get some good deals on there, although EX motor cases tend to get snapped up pretty quickly.

Snap ring motors do use o-rings, but they are not as 'fiddly" as aerotech motors, in my opinion. The o-rings are to provide a seal for the nozzle and the forward bulkhead- 2 orings per motor, usually.

Text me if you have any more specific questions.

I just requested access to the research forum. Should be able to get in to more detail soon.

djs said:

Forum access aside- I would recommend to start with a small case (G or H motors), and have a somewhat disposable rocket that you can test fly things in for their first flight test. Please note that most EX motors do not have ejection charges, so it would have to be electronic deploy. I use a wildman interceptor 54 with a nose cone av bay. I have an eggtimer quark in the av bay to pop the chute at apogee. Not a large amount of cost if something were to go kafloopy, and it's easy to get ready at the range.

Some good recommendations on cases above- I would also recommend the 38mm Loki cases. Also watch the for sale section of the forum- you can get some good deals on there, although EX motor cases tend to get snapped up pretty quickly.

Snap ring motors do use o-rings, but they are not as 'fiddly" as aerotech motors, in my opinion. The o-rings are to provide a seal for the nozzle and the forward bulkhead- 2 orings per motor, usually.

Text me if you have any more specific questions.

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I'm trying not to beat you up with direct questions. You've already provided so much info and time. And now I have a lot more. And soon I'll have even better access.

There are some good threads in there for beginners in there, prepare for a LOT of reading.

https://en.wikipedia.org/wiki/Japan's_space_development

If you read the history section of "Japan's space development", they started with minimal knowledge and very small first articles. Good approach.

As ttabbal wrote, your best first work should be to read + read + read. Things happen fast in the world of high energy chemical reactions.

Kruegon said:

A recent search turned up posts on another forum that actually has formulas. Can't that get you in trouble with Homeland Security? But I will admit it explained a lot. Not enough, but a lot.

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In reality? No. None of this stuff is classified. People get in a crazy twist about ITAR. They'll tell you the world will end and black helicopters come attack you.

This stuff is not top secret.

DavidMcCann said:

In reality? No. None of this stuff is classified. People get in a crazy twist about ITAR. They'll tell you the world will end and black helicopters come attack you.

This stuff is not top secret.

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Agreed. I think it is more for liability, but that is just a guess.

I got a lot of early info / formulas from other sites - some data is pretty old. Either way, you need to follow the rules of the forums you belong to.

If you have not done so already, check out Chris Short & Chris' Rocket Supplies for chemicals. Also, Dan Patell and Easy Research Rocketry for hardware and other tid-bits. I may have missed it in earlier posts, but get yourself a hands-on mentor that will work with you as you learn the basics of motor making. There are some good ones down your way, including Chris Short. Be safe, have fun, and learn; I think you will find this aspect of the hobby rewarding and challenging.

The restricted access research forum was created by the former owner of this forum, Kevin Trojanowski (troj). I recall seeing a post where he stated that one of things (the thing ?) that motivated him to do this was a conversation he had with a representative of a governmental agency. Still searching for that dang post so I can prove my memory isn't completely failing me. :blush: Anyway I don't think the men in black are waiting to take us to Guantanamo and yes, you can find lots of places on the Wacky Weird Web to discussion all manner of chemical formulas for fun and profit. +1 on the advice of finding a local mentor.

samb said:

The restricted access research forum was created by the former owner of this forum, Kevin Trojanowski (troj). I recall seeing a post where he stated that one of things (the thing ?) that motivated him to do this was a conversation he had with a representative of a governmental agency. Still searching for that dang post so I can prove my memory isn't completely failing me. :blush: Anyway I don't think the men in black are waiting to take us to Guantanamo and yes, you can find lots of places on the Wacky Weird Web to discussion all manner of chemical formulas for fun and profit. +1 on the advice of finding a local mentor.

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Generally if one takes a course or works with a mentor they will get one started with recipes. Kurt

I think the best advice you've gotten so far, get a mentor!

I started in EX when I got my L3. I bought a Loki 76/6000 case for my L3 just so I could make my own grains for it. It was the first EX case I owned. What made it work so well was my mentor had a 12 quart mixer where we could mix a complete 3000g load for the Loki case. That was my first mix. It was done at my mentors house, with his materials and his formula. I've since gotten a 6 qt mixer and branched out to my own formula and 38mm and 54mm motors. I'm sure I would not have been near as successful with my start in EX without my mentor. I tend to rely on him more as I learn more.


You asked what equipment and supplies you could buy before hand. I would recommend you don't buy any. Whoever you find as a mentor will have methods and processes that work for them. What equipment you need will depend on those methods and processes to some degree. Once you've learned what your mentor can teach you, you can talk with a other Ex mixers and learn other methods. In my case we used end caps and mandrels and each packing tube was cut to the grain length, the grain was packed and pulled off the mandrel when it set up. There was no cutting to length or drilling of cores needed. Just trim the ends a little and it was ready to go. Your mentor may teach you pourable formulas and methods and drilling the cores. It's all good and works well. Which ever way you start out, you can learn other methods later and those other methods will be much easier to learn once you've learned the basics.

I do have a potential mentor. He told me, "Get your L2 and I'll get you over here mixing".

Of course the unspoken part included to also get my TRA membership lol. Didn't want to pay for both until there was a good reason. So soon I'll be NAR and TRA.

And I'm reading. And reading. Started with Tony's primer. I need to find a chemical glossary. An explanation of the common chemicals used and what effect they have on the motor.

Don't link it here. Don't discuss them. Just a comment on what I needed to find.

I also need to find the above link. If someone has a decent one they can put in the research forum that would be great.

Reply to the last two posts: Dr. McCreary's book. That gives you a basic understanding of what you need to know regarding chemicals and their effect on a formula.

Thank you. I'm going to be checking into that.

"Of course the unspoken part included to also get my TRA membership lol. Didn't want to pay for both until there was a good reason. So soon I'll be NAR and TRA."


Not to bash NAR, but if money is tight, why pay them???

FredA said:

"Of course the unspoken part included to also get my TRA membership lol. Didn't want to pay for both until there was a good reason. So soon I'll be NAR and TRA."


Not to bash NAR, but if money is tight, why pay them???

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My home club is NAR and I'm an officer in the club.

Kruegon said:

My home club is NAR and I'm an officer in the club.

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I've never regretted my dual membership; it allows me to vote in both organizations, serve in any office in my dual section/prefecture, and launch at any launch. The additional money is $5.84 per month, less than a fancy drink somewhere.


Steve Shannon