Range - Ch 10 Flashcards Preview

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Flashcards in Range - Ch 10 Deck (16):
1

Specific Range

Distance flown per unit of fuel

2

SAR

Specific Air Range: Air Mass related

3

SGR

Specific Ground Range: Wind Affected

4

Fuel Flow

Turbojet: Fuel flow is proportional to Thrust

Prop: Fuel flow is proportional to power

5

SFC

Specific Fuel Consumption

6

SFC Jet =

Fuel Flow / unit of thrust

Lowest: low temp, high alt, optimum rpm

7

SFC Prop:

Fuel Flow / unit of power

8

Specific Range Jet

= TAS / SFC x Drag

Best range - optimum rpm
1.32VMD

9

Specific Range Prop

TAS / SFC x PWR Required

Piston: Lower altitude : full throttle height
Turboprop: High for prop but lower than Jet (high-mid 20s)

10

Factors Affecting Range

Increasing Mass decreases range

Increasing Wind: SAR Unaffected SGR: Affected

11

Wind Impacts

Headwind - Fly faster into it and spend less time in it
Tailwind - Fly slower in it
For a Jet.

Prop: Mental calculation to work out fuel burn and adjust accordingly

12

Optimum Altitude

Decreases as flight continues

Aim to keep at optimum alt

Cruise climb, would be ideal but clearance issues, ops dictate a step climb

13

Step Climb

Will be told by FMC when to

May avoid flying optimum altitude around jet streams (fuel burn considerations)

14

Long Range Cruise

Mmlc: Operating cost + fuel cost considered
4% faster than 1.32VMD
Reduces range by 1% (99% original)
Mmlc > Mr (max range speed)
Specific Range = 0.99 S.R. Max Range

15

Cost Index

Time/Fuel cost balance

ECON Profile - based on cost index

Higher cost index = more fuel burn

16

Cruise SPD

Reduces as flight goes on

If high cost index: Constant Mach Number