RMS and hooks

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Well-Known Member
Sep 20, 2003
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I have discovered that the "delay" closure of my RMS is hanging up on the forward end of the motor hook. Anybody have suggestions for a solution. Seems like fileing the hood would work with a little patience....

Yep...you found the solution. Get a thin file and get started on that back hook until you have enough clearance.

Next time you build one, trim it off before you glue it together. Or just put in the thrust ring and put in a retainer on the aft end.

yes, filing works OK but it takes patience I don't have. it's easier to file enough off the 24mm than 18mm; with a smaller radius the 18mm ejection caps are closer to the end of the clip.

depending on pliers you have and access in to the MMT, you might try just bending over the tab. that's not as good as filing.

maybe the best thing is to plan ahead when building and either use a grinder to take material off the hook, or omit the hook entirely and just use tape.
One thing I've done in the past is to just reach up through the MMT with a pen or pencil and push the tang of the engine hook partway out of the MMT. Generally keeps interference with RMS from happening and is also less permanent for when you're flying SU motors.

Only works if you haven't glued the top tang down really well. I found I was able to do this consistently with most Estes-type MMTs.

All of you need to put down those files and go out and buy a Dremel MotoTool!

It is the handiest tool for rocketry -- you cannot live without one.

And get the flexible cable extension. A 225 if you can find it. It fits down most MMT's and can fix a myriad of sins.