Aircraft Motion
Physics of Aircraft
Lift
Drag
Weight and Thrust
Secondary Controls
Stability
Straight and Level
Climbing
Descending
Turning
Aircraft Design Features
The Stall
Practice Exam

The Four Forces

The Four Forces

When the four forces of lift, weight, thrust and drag are balanced in flight, the aircraft is said to be in equilibrium. In this state of equilibrium, the aircraft will continue at the same velocity and altitude until something disturbs it – such as an input from the pilot or a gust of wind.