Definition
A unit of torque equal to the rotational force produced when one pound of force is applied at the end of a lever one foot long. In turbine engine instrumentation, foot-pounds expresses the twisting force the engine delivers to the propeller shaft or rotor drive, as displayed on the torquemeter.
Plain English
A way of measuring twisting force. Imagine pushing down on the end of a one-foot wrench with one pound of force — that amount of twist is one foot-pound. The bigger the number, the harder the engine is twisting the shaft.
Context Anchor
Seen on turbine engine instrument discussions, especially turboprop torquemeters that show engine torque.
Derivation
From 'foot' (the length of the lever arm) and 'pound' (the force applied at the end of it). The unit literally describes the setup: one pound of force, one foot away from the pivot point. Knowing this makes the gauge reading easier to picture as a real twisting action, not just a number.
Why Pilots Care
Shows whether engine torque is within safe operating limits during takeoff, climb, and cruise.
Analogy
Think of using a torque wrench on a wheel lug nut. If the wrench is one foot long and you push the end with one pound of force, you're applying one foot-pound of torque. A turbine engine doing the same twist on its output shaft, just on a much larger scale, is what the torquemeter reads.
Intuition Check
Foot-pounds do not mean the airplane weighs a certain number of pounds, and they do not mean feet of altitude. Here, foot-pounds measure twisting force produced by the engine.
Example Sentence 1
After advancing the power levers for takeoff, the pilot checked that torque was stabilized at 1,800 foot-pounds, within the engine's limit.
Example Sentence 2
The pilot reduced power when foot-pounds approached the redline limit.