Modifying AT reloadable closures for use as interstage coupler

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

J Blatz

Well-Known Member
TRF Supporter
May 8, 2010
Reaction score
Let's say that a fella, a friend of mine, a guy I know, is wanting to flying a minimum diameter 29mm job using the upper stage motor as the interstage (ie approx 1" of the upper stage motor slides into the top of the booster airfame and holds things together until upper stage ignition). This used to be easily done with single use motors which didn't have thrust rings. Well now I believe all the AT single use 29mm motors ave thrust rings (maybe the F50 doesn't?) so that option is out.

Could the aft closure on an AT 29MM reloadable be turned down so that the thrust ring part is removed? Seems doable, right?
Well now I believe all the AT single use 29mm motors ave thrust rings...
The DMS motors have glued-on cardboard thrust rings which could be cut off without too much trouble.
CTI loads also have the power pellet for ignition. . Although cost is same of more than dms

Worth mentioning, Composite motors can't be gap staged like BP motors, so you will need some sort of electronics to fire the 2nd stage. Another area to explore, maybe is the 29mm BP motors currently being offered by estes if you don't have the electronics capability to fire the upper stage.