Definition
An engine instrument found on some turboprop aircraft that displays the power being produced by the engine in units of shaft horsepower (shp). It is driven by a torque sensor in the reduction gearbox, with the reading derived from measured torque and propeller shaft rpm.
Plain English
A cockpit gauge that shows how much power the engine is currently delivering to the propeller, measured in horsepower.
Context Anchor
Seen on the engine instrument panel of some turboprop airplanes, especially when setting takeoff, climb, or cruise power.
Derivation
The term combines 'horsepower,' a unit of power coined by James Watt in the 1780s to compare steam engines to draft horses, with 'gauge,' meaning a measuring instrument. So the gauge literally indicates the engine's power output in horsepower.
Why Pilots Care
Confirms the engine is delivering the power needed for safe takeoff and climb performance while helping avoid overstress or insufficient thrust.
Intuition Check
A horsepower gauge does not directly show airspeed or thrust. It shows engine power output, which the propeller then turns into pulling force.
Example Sentence 1
After advancing the power levers for takeoff, the pilot checked the horsepower gauge to confirm the engine was producing the published takeoff power.
Example Sentence 2
In level cruise the pilot reduced throttle until the horsepower gauge showed the target setting for best fuel economy.