[Fragment]

The only reason for tilt-rotors is when you need to keep the main body of the aircraft level.

The only problem with tail-sitters is the pilot (and possibly the payload).

[lutusp]

> The only reason for tilt-rotors is when you need to keep the main body of the aircraft level.

Actually, a tilt-rotor can be manipulated to make the aircraft go where you want it to. The same idea explains how helicopters make their way across the landscape.