Simple Affordable Flying. Wherefore Art Thou? On condition is Not well founded in science either, especially with 2 strokes . Stick to the TBO. It's NOT there for Nuthin. Running them over TBO makes the engines More expensive to rebuild than Otherwise would be the Case . That's a Proven Fact. IF you operate from the right Place you could cope with engine failures and fly with a real Rotary with really Low hours between repair. Fit and Forget is Nerd thinking. You make your own Luck. Nev