I guess I'm whipping a dead horse here and expect to be brought up on the carpet but I was looking at Warp Drive props recently and although they've had some problems with hubs cracking and prop blades separating it seems to be with the lighter weight hubs and not their HP hubs, otherwise they're pretty bullet proof. Seems that the props aren't optimum for faster airplanes as they don't have any washout and have a constant pitch from the root to the tip and what happens on faster airplanes is they end up cavitating towards the root and become inefficient. Another consideration is their 2 blade props aren't recommended for 4 cylinder engines production or otherwise as they are prone to inducing distructive stresses on the hubs between power pulses but work well on 6 cylinder engines also stresses are imposed when the prop cavitates that are hard on the hubs and cranks. Seems the 3 blade props correct the problem but from what I've gleaned about props is for a faster airplane a 2 blade prop is more efficient as the third blade is only more drag as the extra bite you might get from the third blade is not counteracted by the additional drag the third blade imposses and you actually end up on the negative side in the drag department. This is by no means the definitive answer just food for thought
