RE: Which engine for WM T-34 Mentor?
As these inexpensive and agile aircraft are being used extensively for pylon racing, the required engine is the O.S. 46 FX.
A new O.S. motor, the .46 AX has just been introduced to replace the FX. The old .46 has been discontinued and is hard to find. The new AX is very powerful and lends itself perfectly to the WM T-34. And at around a hundred bucks it doesn't hurt the wallet to much!
Mikey