I recently received an Aerotech RMS 29/40-120, my first reloadable system. Not wanting to look like a total fool when I went to the local launch, I figured a practice assembly and static firing was in order. I assembled the engine with an F22J reload kit, and was pleasantly surprised at the simplicity... it went together in about 10 minutes. Into a static stand, hook it up, and presto..... worked like a charm.
I let the motor cool, and disassembled it for cleaning. I was somewhat surprised to note the paper grain holder was ruptured along one seam, with clear evidence of leakage (physical expansion, soot, charring). The rupture apparently occurred just at the top of the fuel grain (reload is a short grain + spacer).
Two questions occur-- is this sort of rupture normal? If so, does it eventually weaken the case?
Now, a totally different question. It's freezing here more than half the year... if you want to fly, you freeze. The Aerotech RMS case uses O-rings, and I can't help but think "Challenger". Have any problems been reported using these motors in freezing (or even sub-zero) temperatures? I found nothing on the Aerotech site.
TIA for any input!
Kevin