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Maximum Range Maximum Endurance Econ

The document discusses different cruise speeds for aircraft: 1) Maximum Range speed provides the best fuel mileage but the slowest speed. Maximum Endurance speed gives the minimum fuel flow and can be used for holding patterns. 2) Long Range Cruise speed is 99% of Maximum Range speed, achieving a significant speed increase over Maximum Range with only a 1% reduction in fuel efficiency. 3) Economic (ECON) cruise speed results in the lowest operating cost per mile considering fuel costs and time-related fixed and variable costs, as determined by the airline's cost index. The ECON speed is calculated based on various factors and adjusted for winds.

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AmirAli Mohebbi
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115 views11 pages

Maximum Range Maximum Endurance Econ

The document discusses different cruise speeds for aircraft: 1) Maximum Range speed provides the best fuel mileage but the slowest speed. Maximum Endurance speed gives the minimum fuel flow and can be used for holding patterns. 2) Long Range Cruise speed is 99% of Maximum Range speed, achieving a significant speed increase over Maximum Range with only a 1% reduction in fuel efficiency. 3) Economic (ECON) cruise speed results in the lowest operating cost per mile considering fuel costs and time-related fixed and variable costs, as determined by the airline's cost index. The ECON speed is calculated based on various factors and adjusted for winds.

Uploaded by

AmirAli Mohebbi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PPT, PDF, TXT or read online on Scribd
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Maximum Range

Maximum Endurance
ECON

Wen-hung wang
Maximum Range
• Maximum Range speed is obtained from the
largest ratio of TAS/FF
Maximum Range
• MRC speed is the speed for best
fuel mileage
•May be obtained by entering a
cost index of 0
Maximum Endurance
• The horizontal tangent to the curve gives the
minimum FF and thus the Maximum Endurance
speed
Maximum Endurance
•Max. Endurance => min drag => min. FF
•Can be flown in the holding pattern
•In climb it’s close to maximum angle of climb
speed.
•In level flight it provides relatively constant
pitch attitudes and requires little change in
thrust at different flap settings.
Long Range Cruise (LRC)
• Long range speed = 99% maximum
range speed
Long Range Cruise (LRC)
• LRC was defined to achieve a significant increase
in speed compared to MRC, with only a 1% loss in
specific range
• This speed is not modified for head or tail wind
conditions and results in a constant angle of attack
• Both MRC and LRC speed increases with
increasing altitude up to the calculated optimum
altitude where they remain constant. At a constant
altitude, speed for both cruise regimes decreases
with decreasing weight
ECON

• Cost index (CI) is determined by the airline usi


ng a formula that takes into account the fuel co
sts and time related costs, both fixed and varia
ble, to achieve minimum cost.
• CI = Time related cost / Fuel cost
• ECON cruise speed results in minimum operati
ng cost per nautical mile travelled at the specifi
c cruise altitude
ECON
• In FMC, It is calculated based on the
current cost index, altitude, air temperature,
wind and gross weight; then adjusted for
current or predicted wind at the top of climb
How ECON speed is determined
THE END

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