During hovering flight, a single main rotor helicopter tends to move in the direction of tail rotor thrust. This lateral movement is called

During hovering flight, a single main rotor helicopter tends to move in the direction of tail rotor thrust. This lateral movement is called

• A. Translating tendency
• B. Translational lift
• C. Transverse drift
• D. Yaw movement

Answer: (A)

Translating tendency is the lateral drift a single-main-rotor helicopter experiences in hover, moving in the direction of the tail rotor thrust. The tail rotor’s anti-torque thrust acts on the tail and, through the aerodynamics of the rotor downwash and fuselage interaction, causes the helicopter to tend to slide sideways rather than stay perfectly still. To hold a hover, a pilot applies slight cyclic input to tilt the rotor disk enough to produce a horizontal component of lift opposing that drift, effectively counteracting the tendency. Translational lift is the increased efficiency once the helicopter moves forward, which isn’t about hover drift, and yaw movement refers to rotation about the vertical axis, not sideways translation.

Translating tendency is the lateral drift a single-main-rotor helicopter experiences in hover, moving in the direction of the tail rotor thrust. The tail rotor’s anti-torque thrust acts on the tail and, through the aerodynamics of the rotor downwash and fuselage interaction, causes the helicopter to tend to slide sideways rather than stay perfectly still. To hold a hover, a pilot applies slight cyclic input to tilt the rotor disk enough to produce a horizontal component of lift opposing that drift, effectively counteracting the tendency. Translational lift is the increased efficiency once the helicopter moves forward, which isn’t about hover drift, and yaw movement refers to rotation about the vertical axis, not sideways translation.