Definition
The forward force produced by a rotating propeller as it accelerates a mass of air rearward. The propeller's blades act as rotating airfoils, and the difference in pressure between their forward and rear surfaces, combined with the rearward acceleration of air, generates a forward-acting force on the airplane along the propeller's axis of rotation.
Plain English
The pulling (or pushing) force the spinning propeller creates that moves the airplane forward through the air.
Context Anchor
Encountered when learning how the airplane accelerates for takeoff, climbs after liftoff, and maintains speed in cruise.
Derivation
Propeller comes from the Latin propellere, meaning to drive forward. Thrust is from Old Norse thrysta, to push or press. Together the term literally describes the forward-driving push produced by the propeller.
Why Pilots Care
Propeller thrust is the primary force that overcomes drag and allows acceleration for takeoff and sustained climb performance.
Analogy
A propeller is like a strong fan aimed backward. As it sends air behind the airplane, the airplane is pushed or pulled forward.
Intuition Check
Do not confuse propeller thrust with engine power. Engine power turns the propeller; propeller thrust is the forward force the propeller creates.
Example Sentence 1
On the takeoff roll, propeller thrust accelerates the airplane until enough lift is generated for liftoff.
Example Sentence 2
In cruise, propeller thrust is adjusted with power and pitch to exactly balance drag for constant airspeed.