RE: Hanger Nine Twin Otter build
We recommend the 36's because they fit so nicely in the cowls and have plenty of power - very comparable to a good 40. The TPS 46's will of course work with the airplane but the extra power is unnecessary on this lightly loaded airplane. As a note to everyone, we flew the very first prototypes on the EFLPower 15's and it flew well. On the Power 25's the takeoff performace is awesome and the single engine performance leaves nothing to be complained about either.
Pete