The Four Forces of Flight: Lift, Weight, Thrust, and Drag – how these forces interact to achieve equilibrium during steady level flight of an aircraft.

When are the four forces that act on an aircraft in equilibrium?

During unaccelerated level flight.

The four forces that act on an aircraft are lift, weight, thrust, and drag. An aircraft is said to be in equilibrium when the sum of these four forces is equal to zero. This occurs during steady level flight and when the aircraft is neither accelerating nor climbing or descending.

More specifically, lift is the force that opposes weight, and is generated by the wings of the aircraft. Weight is the force that is caused by the gravity acting on the airplane, pulling it towards the ground. Thrust is the force that opposes drag, and is generated by the aircraft’s engines. Finally, drag is the force that is caused by the resistance of the air, opposing the motion of the aircraft.

When the aircraft’s lift force is equal to its weight force, and thrust force is equal to its drag force, the aircraft is in equilibrium, and it maintains a steady level flight path. This means that the aircraft is not accelerating or changing its altitude, and the passengers and crew on board will feel a constant force of gravity acting upon them.

More Answers: