What are the four forces always acting on an airplane?

The four forces acting on an airplane are lift, weight, thrust, and drag.

Lift is the upward force generated by the wings, allowing the airplane to rise and stay in the air. It is created due to the difference in air pressure on the upper and lower surfaces of the wings, which is influenced by the aircraft's speed and the angle of attack.

Weight is the downward force acting on the plane due to gravity, pulling it toward the Earth. It is the total mass of the aircraft, including its fuel, crew, passengers, and cargo.

Thrust is the forward force produced by the airplane's engines. It propels the aircraft forward and must be sufficient to overcome drag, the force that opposes motion due to air resistance.

Drag is the resistance force that acts opposite to the direction of thrust. It is caused by the interaction between the airplane's surfaces and the air as it moves through it. Drag increases with the aircraft's speed and surface area.

Understanding these four forces is essential for a pilot because they play a crucial role in aircraft performance and flight maneuvers. Balancing these forces during flight is key to achieving stable and controlled flight.