Computer drawing of an airliner showing the thrust vector.

Thrust is the force which moves an aircraft through the air. Thrust is generated by the engines of the airplane. What is thrust?

Thrust is a mechanical force. It is generated most often through the reaction of accelerating a mass of gas. The engine does work on the gas and as the gas is accelerated to the rear, the engine is accelerated in the opposite direction. The acceleration of the engine mass produces a force on the aircraft. How the aircraft responds depends on the balance of forces on the airplane.

The physics involved in the generation of thrust is introduced in middle school and studied in some detail in high school and college. To accelerate the gas, we have to expend energy. The energy is generated as heat by the combustion of some fuel. The thrust equation describes how the acceleration of the gas produces a force. The propulsion system used on an aircraft may vary from airplane to airplane and each device produces thrust in a slightly different way. We will discuss four principal propulsion systems; the propeller, the turbine,or jet, engine, the ramjet, and the rocket.


Button to Display Slide


Guided Tours

Button to Display Aerodynamics Index Button to Display Propulsion Index Button to Display Model Rocket Index Button to Display Kite Index


Back to top

Go to...

Beginner's Guide Home Page

byTom Benson
Please send suggestions/corrections to: benson@grc.nasa.gov