Rocketarium 24mm motor retainer not working with RMS casing?

[mark4ro]

Hello Folks, I just finished off a new rocket build and set it up with a fancy Rocketarium 24mm motor retainer only to learn that it only works with disposable motors! The thrust ring on My Aerotech RMS case is too wide for this retainer to close! Did anyone else run into this and is there a wider cap that I can buy so it can close? I don’t like taping motors in for flying. The AeroPac retainer cap is wider but the threads are different.
Any ideas appreciated.
Thanks
Mark

 

[Lotronex]

That feels like a pretty big oversight. The Rocketarium website even states:

For use with BT-50 tubes and 24 mm motors, including Estes/Quest 24 mm D-E motors, Cesaroni Pro24, Aerotech single use and Reloadable 24 mm motors.

My suggestion would be to contact Rocketarium and see if they have an updated cap they can send you. In the meantime, you could try 3D printing a temporary cap.

 

[SolarYellow]

24/60 aft closure is larger OD and longer than 24/40.

 

[mark4ro]

That feels like a pretty big oversight. The Rocketarium website even states:


My suggestion would be to contact Rocketarium and see if they have an updated cap they can send you. In the meantime, you could try 3D printing a temporary cap.

Thanks for the reply, I did contact Rocketarium but it was after hours. Hopefully they have a wider cap. I don’t have any experience yet with 3D printing so not sure that option would work. I never realized until now how different the thrust ring was on the RMS.

 

[ljwilley]

Nice rocket, though!

 

[jmasterj]

The 24/60 doesn't play nice with a number of retainers, including 29mm ones when it's in an aeropack adapter.

 

[4regt4]

The 24/60 can be used (barely) with the Estes 24mm retainer. And I've used them with the Estes 29mm using one of the cardboard/plywood adapters available from Apogee and LOC.

For the 24/40 case, I'm using the plastic Estes adapter.

Hans.

 

[mark4ro]

Thank you all for your replies. I did get in contact with the good folks at Rocketarium. They acknowledged the problem and said at the time of design there was only 1 reload available for the 24/60 (but there are now at least 4 now). They were also kind enough to try to 3D print (as @Letronex suggested) a new cap that will fit. Hopefully that works. I'll keep you posted.

@4regt4 , Yes. I did try fitting the 24/60 in a build I have with an Estes 24mm retainer and it does catch on a short amount of thread. Have you flown this configuration? Do you think it will be strong enough to hold?
Thanks
Mark

 

[mh9162013]

Thanks for posting this OP, as I've always been curious about how RMS engines work with threaded retainers.

But just for clarity: the AT RMS 24/40 will work just fine with the Rocketarium's 24mm threaded metal retainer, but the RMS 24/60 will not?

 

[jmasterj]

If you've already installed the retainer, I'd just friction fit the 24/60 motors. If not, you could explore the 3D printed options on the various repositories (thingiverse, etc.).

 

[4regt4]

@4regt4 , Yes. I did try fitting the 24/60 in a build I have with an Estes 24mm retainer and it does catch on a short amount of thread. Have you flown this configuration? Do you think it will be strong enough to hold?
Thanks
Mark

Yes, I've done it numerous times. If you inspect how the parts (retainer body, retainer cap, motor case) fit together and their threaded surface, you can grind just a small amount away on the retainer body to get about another 1/4 turn on the retainer cap. It looks to be about 1/2 turn w/o modifying, 3/4 to almost a full turn after modifying.

I also do this with HP 29mm cases using the Estes 29mm retainer. I can get a full turn on those. Although there have been a sparse few comments here about people using them w/o modifying.

Hans.

 

[mark4ro]

So Cheers to Rocketarium. In less than one day they responded to my issue and 3D printed a revised cap to fit the 24/60. I'll keep you posted on how well it works. Nice to see real customer service still exists.
Thank you Rocketarium and thank you to everyone who contributed yesterday to my post.

 

[mark4ro]

Thanks for posting this OP, as I've always been curious about how RMS engines work with threaded retainers.

But just for clarity: the AT RMS 24/40 will work just fine with the Rocketarium's 24mm threaded metal retainer, but the RMS 24/60 will not?

Correct! I’m told the 24/40 aft closure is much smaller than the 24/60, but I don’t have first hand experience yet. I’ll post back when I do.

 

[Lotronex]

Correct! I’m told the 24/40 aft closure is much smaller than the 24/60, but I don’t have first hand experience yet. I’ll post back when I do.

You can find the drawings for both here, but that's correct, the 24/40 is .125in thick while the 24/60's is .250in thick.

 

[rocketarium]

RMS 24/40 and all known (to me) 24mm Casings and Single-Use motors work with this retainer. The problem with 24/60 is not the lenghth of the closure, but its diameter.

 

[afadeev]

But just for clarity: the AT RMS 24/40 will work just fine with the Rocketarium's 24mm threaded metal retainer, but the RMS 24/60 will not?

This is to confirm that AT RMS 24/40 case works perfectly fine with Rocketarium's 24mm retainer. As well as with the Estes 24mm retainer (which is way bulkier).

I've never wanted to invest into 24/60 hardware, and probably never will. So no comment on that white elephant.

HTH,
a

 

[mark4ro]

Yes, I've done it numerous times. If you inspect how the parts (retainer body, retainer cap, motor case) fit together and their threaded surface, you can grind just a small amount away on the retainer body to get about another 1/4 turn on the retainer cap. It looks to be about 1/2 turn w/o modifying, 3/4 to almost a full turn after modifying.

I also do this with HP 29mm cases using the Estes 29mm retainer. I can get a full turn on those. Although there have been a sparse few comments here about people using them w/o modifying.

Hans.

Thanks for the tip on the 24mm Estes retainer. Ground it down a bit with the Dremel and got the same result as you. Almost a full turn.