its been done....
Seriously tho'....the PAV was solved about 20 yrs ago by the Voljet. It uses a standard turbine to copress air and squirt it out of the tips of the rotors. No need for a boom (tail) as in standard helicopters. Its quiet, safer than most helios and can be flown with no hands ! so its easy to train people. Those megacorp helicopter manufacturers wont take it up tho' because amongst other things it requres much less maintenance than a standard heli.
Watch the video on youtube. Its a big file but look at what it does at 7 mins into the video. Rises vertically like its on elastic !