ARMY V-280  

Little or no ability to auto depending on phase of flight. unable to glide due to wing surface area being too small. no recovery from a vortex ring state. Slow transition to wing loading. Boeing helped build the V-22 and decided against siding with Bell on this project. Sold all rights off on the AW 609. I'm guessing they know something or they would be involved if they believed it a viable option. On a side note Boeings original design on the tilt rotor concept had vertical engines and only moved the rotors. Interesting now Bell has decided that's the better option.