What two forces need to be in balance for a helicopter to hover?

What two forces need to be in balance for a helicopter to hover?

• A. Thrust and drag
• B. Lift and weight
• C. Lift and thrust
• D. Weight and drag

Answer: (B)

In a hovering helicopter, the critical balance involves lift and weight. Lift is the force created by the helicopter's rotor blades as they spin and push air downwards, and this upward force needs to be equal to the downward force of weight, which is determined by the mass of the helicopter and the force of gravity acting on it. When these two forces are equal, the helicopter can maintain its position in the air without ascending or descending. Thrust and drag, while important in various phases of flight, do not directly correspond to a helicopter's ability to hover. Thrust typically refers to the forward force produced by the helicopter’s engines and rotors, while drag is the resistance the helicopter faces moving through the air. In a hover, the aircraft is neither moving forward nor backward, so the relationship between thrust and drag is not as significant as the balance between lift and weight.

In a hovering helicopter, the critical balance involves lift and weight. Lift is the force created by the helicopter's rotor blades as they spin and push air downwards, and this upward force needs to be equal to the downward force of weight, which is determined by the mass of the helicopter and the force of gravity acting on it. When these two forces are equal, the helicopter can maintain its position in the air without ascending or descending.

Thrust and drag, while important in various phases of flight, do not directly correspond to a helicopter's ability to hover. Thrust typically refers to the forward force produced by the helicopter’s engines and rotors, while drag is the resistance the helicopter faces moving through the air. In a hover, the aircraft is neither moving forward nor backward, so the relationship between thrust and drag is not as significant as the balance between lift and weight.