What term describes the additional lift obtained when entering forward flight due to rotor efficiency?

What term describes the additional lift obtained when entering forward flight due to rotor efficiency?

• A. Translational Lift
• B. Induced Lift
• C. Ground Effect
• D. Dynamic Lift

Answer: (A)

Translational lift is the extra lift you gain when the rotor system starts to move into forward flight and encounters undisturbed air ahead of the rotor disc. In hover, the rotor is working in its own downwash, which creates recirculating flow and a higher induced inflow that reduces the effective blade angle of attack and makes power demand higher for the same weight. As you accelerate forward, the rotor disc slices through air that hasn’t been churned by the rotor, so the blades see more forward airspeed and become more efficient. That increased efficiency produces additional lift for the same blade pitch, or allows you to hold altitude with less power. This effect grows with forward airspeed and is distinct from ground effect (which occurs near the ground). It’s not the term used for the general lift component or for downwash-related effects, but specifically the boost in lift from moving into undisturbed air.

Translational lift is the extra lift you gain when the rotor system starts to move into forward flight and encounters undisturbed air ahead of the rotor disc. In hover, the rotor is working in its own downwash, which creates recirculating flow and a higher induced inflow that reduces the effective blade angle of attack and makes power demand higher for the same weight. As you accelerate forward, the rotor disc slices through air that hasn’t been churned by the rotor, so the blades see more forward airspeed and become more efficient. That increased efficiency produces additional lift for the same blade pitch, or allows you to hold altitude with less power. This effect grows with forward airspeed and is distinct from ground effect (which occurs near the ground). It’s not the term used for the general lift component or for downwash-related effects, but specifically the boost in lift from moving into undisturbed air.