Interesting paper about the variable diameter tilt rotor. Sounds more complex than the V-22 if that is possible.
I saw the V-22 fly at Oshkosh earlier this month.
And the Martin jetpack was demonstrated for its first public display. The jetpack was really two ducted fans with a piston engine for power. It managed to climb about 4 feet. The designer said flights of 6 feet have been accomplished. It seemed to require two assistants for stability.
slowrotor