Joined: 11 Dec 2005
|Posted: Mon Apr 02, 2012 11:38 am Post subject: Jet Fuel Consumption
| Fuel consumption for a jet can be measured in terms of:
1) The mass of fuel burnt for each unit of thrust. This is (thrust) specific fuel consumption (SFC).
Jet SFC = Fuel Flow / Thrust
SFC reduces with altitude up to the tropopause after which it remains constant.
2) Air distance flown for each unit of fuel. This is Specific Air Range (SAR).
SAR = TAS / Fuel Flow
SAR improves with height as the increase in TAS at altitude adds to the benefit of reducing SFC