Coning is a phenomenon which affects
helicopter rotor 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, mobil ...
, 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 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.
See also
*
Unequal rotor lift distribution
Unequal rotor lift distribution is an effect where the blades of a helicopter rotor generate more lift at the rotor tips than at the rotor hub.
A helicopter rotor blade is an aerofoil, which is driven through the air to create lift. The lift ge ...
References
Helicopter aerodynamics
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