Range Flashcards
(13 cards)
Range is defined as
Distance covered on the available fuel
Specific range is the ratio between
True air speed and rate of fuel consumption
SAR
Specific Air Range:
TAS/Fuel Flow
Or
TAS —————————- SFC X (Thrust Required)
SGR
GS/Fuel flOW
Fuel Flow vs thrust
Higher thrust = more fuel flow (Jet)
Higher power = more fuel flow (Propeller)
Specific Fuel Consumption in a jet and propeller aircraft
Fuel flow per unit of thrust in a jet
Fuel flow per unit of power in a propeller aircraft
SFC is lowest when
Air temperature is low engine running as design RPM 90-95%
Best range cruise speed for a jet is
1.32VMD
Best range cruise speed for a propeller aircraft is
VMD
Optimum altitude
Best range
2000ft deviation = 1% change in consumption
8,000ft deviation = 10% change in consumption
Wind Vs Range
Does not affect SAR
SGR
Tailwind - Slightly slower than 1.32MD
Headwind - Slightly faster than 1.32MD - flying faster to compensate for wind
Long range cruise speed
Flying faster than 1.32MD MMR speed to complete more flights
MLRC = Long range cruise speed
SR long range = 0.99 x SR max range
4% faster than MMR
SFC Consumption Formula
Fuel Flow/Thrust