Definition
A unit of work or torque in the U.S. customary system, equal to the energy transferred when a force of one pound acts through a distance of one foot in the direction of the force. When used as a measure of torque, it expresses the twisting effort produced by one pound of force applied at the end of a one-foot lever arm.
Plain English
The amount of effort it takes to push something with one pound of force over a distance of one foot, or to twist something with one pound of force on a one-foot wrench.
Context Anchor
Seen in basic aircraft physics, engine power explanations, and discussions of work, energy, or lifting force.
Derivation
The name simply combines the two units involved: one foot of distance and one pound of force. The order matters by convention — 'foot-pound' for work or torque, distinguishing it from the older 'pound-foot' usage that some engineering texts still use interchangeably.
Why Pilots Care
Correct foot-pound values ensure critical components such as propeller bolts are tightened without risk of loosening or damage.
Grounding Statement
If you pull with one pound of force and the object moves one foot in the direction of the pull, one foot-pound of work has been done.
Intuition Check
Do not read foot-pound as a foot plus a pound separately. It is one unit that measures work or energy: force applied through distance.
Example Sentence 1
The maintenance manual calls for the spark plugs to be torqued to 30 foot-pounds.
Example Sentence 2
The engine produces 350 foot-pounds of torque at takeoff power.