Reliadable motor question

[Trenman]

This is a real newb question. Have been building for a while but never with a reloadable motor. Just finished my carbon mongoose 38mm and am waiting for my reliadable motor tube to arrive. My question is how does it stay in the bottom of the rocket? Do I somehow add threading to the bottom or is it held in with a bolt or the same way a single use is? Please advise.

 

[powderburner]

I don't think that is such a "noob" question- it's not all that obvious how to retain the RMS casing if you haven't seen it before.

There area a few different ways but they are basically the same, they use a metal clip that screws on from the bottom (outside the rocket) and holds the motor case in. There are products that you can buy, and others that you can make yourself. But you definitely need to use something because otherwise that motor case is gonna be expensive to lose when it pops out of the rocket.

I don't have any pictures handy to show what to use for motor retention, but I'll bet some of these other guys do.

Edit: here's one-
https://www.coastrocketry.com/Motor Retention.htm

 

[Toyguy]

Not that I would recommend it, given the cost, but I have successfully used the old friction-fit method with an RMS case in the past :y:

 

[El Cheapo]

Heck, Yeah...Friction fit the motor and then run a couple wraps of tape around the protuding motor tube & then fold over the end of the casing. Works like a charm.

 

[MaxQ]

friction fit a 38mm reload...with tape..?

Once that motor burns, the tape will heat up....you'll have weaker adhesion, you'll more than likely loose the motor case upon ejection, and then you'll loose the rocket, as there will be no ejection to pop the main.

Good luck.

I wouldn't do it.
That Mongoose is too nice to loose, and pretty dangerous coming in ballistic.

 

[El Cheapo]

Oh, Ye of little faith.

 

[MaxQ]

Fine...go right ahead...it's his nickel anyway.

I saw a Level One go in...he thought friction fit was a good idea for his H reload too

The impact and debris field was good enough for funiest home videos ....
If it had gone through someones car roof it would not have been that funny.

This is a nice rocket...if he could afford the Mongoose he can afford to buy one of these, and do it right.

https://www.aeropack.net/motor_retainers.html
https://blastzone.com/aeropack/partnumbers.asp

38P = Madcow paper, PML and GLR phenolic, Hawk Mt and Performance Rocketry fiberglass

 

[Trenman]

In all seriousness this post has been beyond informative. Aside from just posting an explanation, others have gone out of their way to post links and how-to guides. Thanks to all! Such a wealth of knowledge. L

 

[MaxQ]

We all just want to help...and if you can avoid some poblems we may have had that's great too.

 

[Pem Tech]

It would seem that luck with "friction fitting" differs from individual to individual. Personally, I friction fit about everything from 18mm through 38mm and have only come close to losing a case twice, once due to VERY high humidity and once due to me forgetting to actually put tape around the end of the motor tube.
:shock:

Got my L1 on our Space Ark using friction fitting.

My advice, try all the means of retention that call out to you and find the one that works best for you. Aero Pack retainers are very cool, Kaplow clips are easy and cheap, bend a bit of wire in a squared "U" shape and epoxy it to the motor mount tube (the retainer method used on our 3FNC), or slap some tape on the motor case and friction fit.

Let you imagination run wild!
Do it!
Do them ALL!!!
BWHAHAHAHAHAHAHAHAHAHA!!!!

Sorry, did I do that out loud?