specific fuel consumption


specific fuel consumption

[spə′sif·ik ′fyül kən‚səm·shən] (mechanical engineering) The weight flow rate of fuel required to produce a unit of power or thrust, for example, pounds per horsepower-hour. Abbreviated SFC. Also known as specific propellant consumption.

Specific fuel consumption

The ratio of the fuel mass flow of an aircraft engine to its output power, in specified units. Specific fuel consumption (abbreviated sfc or SFC) is a widely used measure of atmospheric engine performance. For reciprocating engines it is usually given in U.S. Customary units of pound-mass per hour per horsepower [(lbm/h)/hp or lbm/(hp·h)], and International System (SI) units of kilograms per hour per kilowatt [(kg/h)/kW]. See Reciprocating aircraft engine

For the gas turbine family of atmospheric aircraft engines, and for ramjets, performance is usually given in terms of thrust specific fuel consumption (abbreviated tsfc or TSFC) expressed as fuel mass flow per unit thrust output with Customary units of pound-mass per hour per pound-force [(lbm/h)/lbf] or SI units of kilograms per hour per newton [(kg/h)/N; 1 N equals approximately 0.225 lbf]. For high-supersonic and hypersonic ramjets, specific fuel consumption is sometimes given in pound-mass per second per pound-force [(lbm/s)/lbf] or kilograms per second per newton [(kg/s)/N]. See Aircraft propulsion, Jet propulsion, Propulsion, Ramjet, Turbine propulsion, Turbojet

specific fuel consumption (SFC)

The quantity of fuel consumed (by weight) to produce one unit of power in one unit of time. In piston engines, the SFC is equal to the mass ratio of fuel/shaft horsepower. In gas turbine engines, the SFC is equal to the mass ratio of fuel/thrust. It is best when its value is minimum. The value of the SFC decreases with height and in colder temperature conditions.