Coning Primary forces involved: 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

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 Resultant Lift Centrifugal Force

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

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