Coning is a phenomenon which affects

helicopter rotor A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) with a control system, that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aero ...

discs. The tips of the helicopter rotor blades move faster through the air than the parts of the blades near the hub, so they generate more

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...

, which pushes the tips of the blades upwards, resulting in a slight cone shape to the rotor disc. This is balanced by centrifugal force. If rotor RPM drops too low, the rotor blades fold up with no chance of recovery. Helicopter rotors are typically designed with washout (twist) so that lift is relatively uniform along the blades. However, because lift increases quadratically with airspeed, coning still occurs at higher RPMs. Some helicopters such as the

Bell UH-1 Iroquois The Bell UH-1 Iroquois (nicknamed "Huey") is a utility military helicopter designed and produced by the American aerospace company Bell Helicopter. It is the first member of the prolific Huey family, as well as the first turbine-powered hel ...

are designed with "pre-coned" blades, which are curved downwards but lay more flat in flight. The ratio of aerodynamic forces to inertial forces is called the Lock number.

References

Helicopter aerodynamics {{aircraft-stub

See also

References