24mm is a funny motor size.
I've just done a mental search, and have only maybe build 4 or 5 24mm MMT rockets.
One of them is still in flying condition, somewhere in the basement. Two new ones (Expedition and LJ-II) are in my build pile, courtesy of Estes's black Friday sale.
To answer your questions:
- All other things being equal, APCP motors are harder to CATO then Estes black powder motors.
- That is because larger and longer BP slugs are more susceptible to fracture with temperature cycling, and occasional drops. Drops may accumulate throughout the supply chain, long before the motors came into your possession.
- It's hard to mishandle APCP slugs.
- All other things are not equal. You have to build your 24mm AeroTech APCP motors, and not screw up the build process, not skip any steps, not get distracted, etc. While many of us find assembling reusable motors a fun and enjoyable activity, it does introduce a > 0% error rate into the process.
- Consequently, I've had at least two (2) AT CATOs, but they were all my fault. And those happened early on, when I was still getting on with the art of new screwing up motor assemblies.
- I have had ZERO (0) 24mm Estes CATOs, but I must have been lucky. And/or my sample size is too small. The total count of Estes D's and E's (9's and 12's) I've ever burned is probably in the dozens (mid 2-digits), definitely not 3-digits.
- All of my D's and E's have been sourced from HobbyLobby (via 40% discount), which might suggest that they handle their inventory gently and carefully.
If you are thinking of buying 24mm AT hardware - do it!
F39T is one of my all-time favorite motors, and is a great value!
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