Definition
A unit of torque equal to the twisting force produced by one pound of force applied at the end of a one-foot lever arm. In turboprop engines, foot-pounds measure the rotational force the engine delivers to the propeller shaft, and torque in foot-pounds is one of the primary power indications the pilot monitors.
Plain English
A way of measuring twisting force. One foot-pound is the amount of twist you get when you push with one pound of force on the end of a stick that is one foot long.
Context Anchor
Seen in turboprop engine power and torque discussions, especially when reading engine instruments or operating limits.
Derivation
The name combines the two things being measured: the length of the lever arm in feet, and the force pushing on it in pounds. Multiply them together and you get the twisting strength.
Why Pilots Care
Torque values in foot-pounds directly affect available power for takeoff, climb, and propeller control settings.
Analogy
Think of using a wrench to tighten a bolt. If you push with one pound of force on a wrench that is one foot long, you are applying one foot-pound of torque. A longer wrench or a harder push gives you more foot-pounds.
Intuition Check
Do not read foot-pounds as the airplane’s weight or as fuel quantity. Here it means twisting force. Even though the source writes ft/lb, in this context it is being used for foot-pounds of torque, not feet per pound.
Example Sentence 1
The pilot advanced the power lever until the torque gauge read 1,800 foot-pounds for takeoff.
Example Sentence 2
Free-turbine designs transmit power to the propeller through a shaft measured in foot-pounds of torque.