The 4 forces that affect flight
Four forces act on an aircraft, making up the ‘principles of flight’.
These main forces are thrust, drag, weight, and lift.
Thrust
Thrust is the forward force produced by the propeller. It opposes or overcomes the force of drag.
Drag
Drag is a rearward, retarding force caused by disruption of airflow by the wing, fuselage, and other protruding objects. Drag opposes thrust and acts rearward parallel to the relative wind
Weight
Weight is the combined load of the aircraft, the crew, the fuel, and the baggage. The weight pulls the aircraft downward because of the force of gravity.
Lift
Lift opposes the downward force of weight, produced by the dynamic effect of the air acting on the wing and acts perpendicular to the flight path through the wing’s centre of lift.
The 3 axes of movement
An aircraft moves in three dimensions and is controlled by moving it about one or more of its axes.
The lateral or pitch axis extends across the aircraft on a line through the wing tips, passing through the centre of gravity.
The longitudinal, or roll, axis extends through the aircraft from nose to tail, with the line again passing through the centre of gravity.
The vertical, or yaw, axis passes through the aircraft vertically, intersecting the centre of gravity.
All control movements cause the aircraft to move around one or more of these axes and allow for control of the aircraft in flight.
