RE: best t-maxx engine
Nitro heli engines have a fan on the clutch bell to keep them cool. Also, they have a very narrow power range since the rotors spin between 1500-2000 RPM, with 7-9:1 ratio gives roughly 15K RPM give or take, and they are usually set at a given RPM by the pitch and throttle curves in the controller, some even have governors. They are just designed to work in a very narrow power range and makes gobs of power in that range, car/truck engines make power over a much wider range.