Which force acts upward to keep the UAS in flight?

Which force acts upward to keep the UAS in flight?

• A. Drag
• B. Weight
• C. Thrust
• D. Lift

Answer: (D)

Upward lift is the force that keeps the UAS in flight. It comes from the rotor blades pushing air downward; as the air is pushed down, the craft experiences an equal and opposite reaction that pushes it upward. In steady, level flight, lift must balance the weight pulling the drone downward, so the aircraft stays at the same altitude. Weight is the downward pull of gravity, which lift must counter. Drag is the air resistance opposing the motion, not the upward support. Thrust is the force that pushes the drone forward (and can contribute to vertical motion when the craft pitches), but the specific upward force that counters gravity and keeps the drone aloft is lift.

Upward lift is the force that keeps the UAS in flight. It comes from the rotor blades pushing air downward; as the air is pushed down, the craft experiences an equal and opposite reaction that pushes it upward. In steady, level flight, lift must balance the weight pulling the drone downward, so the aircraft stays at the same altitude.

Weight is the downward pull of gravity, which lift must counter. Drag is the air resistance opposing the motion, not the upward support. Thrust is the force that pushes the drone forward (and can contribute to vertical motion when the craft pitches), but the specific upward force that counters gravity and keeps the drone aloft is lift.