En-route Flashcards
What is range dependent on
Mass Cg position Thrust / drag How much fuel Speed
What is Specific air range (SAR)
TAS / fuel flow
Nautical air miles / kg fuel
What is specific ground range (SGR)
Ground speed / fuel flow
Nautical ground miles / kg fuel
What a jet what is the SAR equation
Specific air range = TAS / drag (or thrust) x specific fuel consumption
For a propeller what is the specific air range equation
TAS / power required x specific fuel consumption
What is the speed for best range for a jet
1.32 Vmd
Where is a piston most efficient
Low / medium alt
Where is a turboprop most efficient
Mid / high alt
Where is a jet most efficient
High alt
What is the speed for best range turboprop
Vmd
How does mass affect the drag curve and Specific range
Drag curve up and right
Tangent steeper therefor more drag
Less SR
What do you do when you burn fuel in cruise to try and maintain optimum level
Step climb
How does wind affect best range speed
Fly slower in tailwind to make most use of the wind
Fly faster in headwind to minimise time in headwind
What is the long range cruise speed for jet
4% faster than 1.32 Vmd
99% of max range achieved
What is the cost index used for
If fuel / operating costs are less then more fuel can be burned for the same price making the flight quicker
What is the cost index
0 - 200
0= lowest cost index = need to be most economic = fly at 1.32 Vmd
50= long range cruise (ish)
200 = highest cost index = can be fastest flight
What is the endurance equation
Endurance = 1 / drag (or thrust) x specific fuel consumption
What is the speed for max endurance at high alt for jet
Vmd
What speed is max endurance for propeller
Vmp
Piston low alt
Turboprop = medium alt
When is mass proportional to fuel flow
Vmd only!
Does wind affect endurance
No
What happens to change over alt with a higher cas
Higher cas lower change over alt
What happens to change over alt with a lower Mach
Lower Mach = lower change over alt
What happens to flight path angle
AOA
Pitch in a descent on Mach
Flight path angle increases
AOA decreases
Pitch decreases
