Editing Thrust-specific fuel consumption (section)

{{short description|Fuel efficiency of an engine design with respect to thrust output}}
'''Thrust-specific fuel consumption''' ('''TSFC''') is the [[fuel efficiency]] of an [[engine]] design with respect to [[thrust]] output. TSFC may also be thought of as fuel consumption (grams/second) per unit of thrust (newtons, or N), hence ''thrust-specific''. This figure is inversely proportional to [[specific impulse]], which is the amount of thrust produced per unit fuel consumed.

TSFC or SFC for [[reaction engine|thrust engine]]s (e.g. [[turbojet]]s, [[turbofan]]s, [[ramjet]]s, [[rocket engine|rocket]]s, etc.) is the mass of [[fuel]] needed to provide the net thrust for a given period e.g. lb/(h·lbf) (pounds of fuel per hour-pound of thrust) or g/(s·kN) (grams of fuel per second-kilonewton). Mass of fuel is used, rather than volume (gallons or litres) for the fuel measure, since it is independent of temperature.<ref>[http://selair.selkirk.bc.ca/Training/Aerodynamics/range_prop.htm Specific Fuel Consumption<!-- Bot generated title -->].</ref>

Specific fuel consumption of air-breathing jet engines at their maximum efficiency is more or less proportional to exhaust speed. The fuel consumption ''per mile'' or ''per kilometre'' is a more appropriate comparison for aircraft that travel at very different speeds.{{cn|date=February 2021}} There also exists [[power-specific fuel consumption]], which equals the thrust-specific fuel consumption divided by speed. It can have units of pounds per hour per horsepower.