This season there has been quite a bit of discussion in the aerobatic community about installing very light weight 2 blade props on 4 cylinder Lyco engines. The short version is that the engine needs mass to absorb the power pulses. This mass can be in the form of 6th order crankshaft counterweights, or a propeller that is heavy enough, or made of the right materials, to absorb the energy pulses. I know of at least one owner who discovered that a carbon fiber 2 blade propeller was bad for his un-counterweighted Lyco. The engine was discovered to be internally destructing. Gears coming apart and other very expensive problems.

The bolt loosening described in the previous post is a symptom of the prop (and the engine) getting beat up by the lack of dampening of the engine power pulses.

Interestingly, 6 cylinder engines have much lower amplitude power pulses so they don't have this problem. 3 blade propellers absorbe the energy differently than 2 blade props (different phase relationships) also, so the 3 blade MT's (wood core blades) seem to work well.

Hope this info helps. My guess is that you should not do that installation.

Best of luck,

Wes
N78PS