I know. mine was a suggsstion for quad vtol minijets.
Fanjet engines are not practical for an Osprey-type aircraft because of the high thrust engines required and the subsequent high exhaust velocities. Also, for maneuverability, fanjets are much less responsive to quick changes in thrust commands than variable pitch rotor blades are.
The Osprey already has a high blade disc loading compared most helicopters and the increased downwash velocity is a problem. A jet engine would have 10x more downwash concentrated in a smaller column of air.
Then there is the issue of the hot exhaust melting tarmac. This is already a problem for the Osprey and the F-35B.