1. Coning
As the helicopter develops lift during takeoff and flight, the
the blade tips rise above the straight-out position and assume
a coned position.
Primary forces involved:
Centrifugal Force: The force which tends to make rotating bodies
move away from the center of rotation
Centrifugal force adds rigidity to the rotor blade, causing it to assume
a straight-out position
Lift: As the collective is increased and lift develops, the blades respond by
rising above the straight-out position

2. Coning
Resultant: The combined effects of centrifugal force and lift
cause the blades to assume a coned position.
The angle between the straight-out position and the path
flown by the blades is the coning angle.
Some amount of coning is normal, however, excessive coning
can create problems
t
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Res
Lift
Centrifugal Force

3. Causes of excessive coning
•Low rotor RPM = Loss of centrifugal force
•High gross weight = More lift required
•High “G” maneuvers = More lift required
•Turbulence = Updrafts increase angle of attack,
which increases coefficient of lift which increases lift

4. Effects of excessive coning
•Decreased rotor area and useful lift
•Stress on blades and blade roots
Resultant or effective lifting area
Lift
Centrifugal Force