slowrotor;
Halftime at the Super bowl?
It appears that this could be significantly more efficient than the current design of tiltrotor; assuming that major problems don't crop up. Theoretically, an increase in the diameter of the rotors will improve the FoM at the expense of high forward speed.
Leishman (2006) says that the current V-22 looses 10% in Figure of Merit due to the downwash on the wing alone. He also says that the streamtube only contracts to 0.8, not the originally held belief that it contracted to 0.707. However he says that it is fully contracted within .25R below the rotor.
AERODYNAMIC OPTIMIZATION OF A COAXIAL PROPROTOR
Dave