A human-powered helicopter (HPH) is a helicopter powered solely by one or more humans carried on board. As in other human-powered aircraft, the power is usually generated by pedalling. It remains a considerable engineering challenge to obtain both the power-to-weight ratio and rotor efficiency required to sustain a helicopter in flight.
AeroVelo's Atlas human-powered helicopter shortly after its first flight
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of short take-off and landing (STOL) or short take-off and vertical landing (STOVL) aircraft cannot perform without a runway.
A Bell 206 helicopter operated by the Los Angeles Police Department Air Support Division
Cabin view looking out from a helicopter in flight
Bell 412CF looking forward from the tail, showing its twin turbine endinge exhausts
1956 Hiller YROE-1 one-man "Rotorcycle" being tested at NASA Ames Research Center