For rotary wing aircraft, you require much more power due to losses and inefficiencies.
Check this link out to see the differences in propellers and rotors:
http://www.heli-chair.com/aerodynamics_101.html
Theoretical thrust developed by common airplane engine - propeller combinations:
300 hp, 78" propeller develops 1,300 pounds of thrust
80 hp, 50" propeller develops 400 pounds of thrust
1.5 hp, 12" propeller develops 10.5 pounds of thrust
Theoretical lift developed by common helicopters:
300 hp, 30' rotor develops 3,400 pounds of lift
25 hp, 12' rotor develops 347 pounds of lift
2 hp, 6' rotor develops 39 pounds of lift