Depends on whether you want to play with Engines OR Fly your Plane. IF you like PLAYING with engines do it with engines in some object that doesn't fly, preferably OR fly where an engine failure doesn't mean you would be lucky to survive. Engine failures can also CAUSE a FIRE which when airborne really becomes a life and death issue very Rapidly.. An aero engine HAS to theoretically Meet Original Performance Parameters till it's removed to be Overhauled.. Nev