To: maxtork
If you tilt the rotor in relation to the mast you would encounter excessive lead lag which could possibly tear the rotor to pieces. This assumes a fully articulated system which also has design limits relative to flapping.. There is a possibility that excessive tilt on a Bell rotor system would exceed the design limits of the underslinging and you may encounter excessive lead lag, which will exceed the structural limits of the rotor system. This does not include mast contact.
But then again, I’m not a graduate engineer.
As far as the efficiency or the V-22 Prop rotor ® is concerned in an auto rotation the ROD can reach 6000 feet per minute. I believe this is the reason for certifying any prop rotor aircraft as a powered lift aircraft and not as a helicopter. That way they don’t have to demonstrate auto rotation.
The length of the Prop rotor ® blades are such that if the aircraft makes a run on landing the blades extend beneath the fuselage and are designed to fracture in small pieces keeping the possibility of shrapnel intrusion into the fuselage to a minimum.
I’ll leave it up to NickLappos to explain the relative merits of the two designs.
