RE: which engine besides OS for Raptor
The OS 32 is nowhere near the TT39 in terms of power. The TT is a bit finickier but once it's settled in I wouldn't trade it for an OS for anything. I have ran both in my Hawk Sport and my Caliber 30. The TT wins hands down. Can't comment on Webra or Irvine as I have never ran one in a heli.
basmntdweller