The training system Evo is actually a .455 engine. I had to search a long time to find any information on it. The three bladed prop with flywheel setup is designed to be a reliable engine for students. Score a 100 on that goal. Mine has only quit twice, and that was due to trash in the high speed needle valve. I flushed it and collected the trash in a coffee filter, so I can't blame the engine for my nose over landings in the weeds. The advantages of the 3 bladed prop are good ground clearance, and it wil slow the plane quickly if you go to idle. Evo claims better noise reduction, but we know that is probably crap...at least to me. I can shove full throttle at any time and count on the engine giving top power. I never worry with the Evo.

You can order a plastic thrust washer for the Evo. It is only something like $2.50. I used that to replace the weighted flywheel, and put on a 11x7 prop. The engine screams and will pull my Xtra Easy 2 out of sight if I let it. The XE2 is a heavy plane too. I haven't flown the trainer in a while, but I miss that Evo a lot. I can only compare the Evo to a TT Pro .46 and an OS .46 FX. I would take my Evo any day. It is totally reliable and I trust it to keep running no matter what. I can't say that for the TT or OS.

RCM reviewed the .46NT and the .61NT in either the Jan or Feb issue if you want to look that up.

The trainer may be about 99% retired now, but not the engine. That is going on the next plane I build, probably a Sig Something Extra or 4 Star.