Range + Endurance

Question 1

How is max range in level flight achieved?

Answer 1

When the greatest distance is covered for the amount of fuel used

Question 2

SAR

Answer 2

Specific air range = air distance flown / fuel used

Question 3

SFC

Answer 3

Specific fuel consumption is fuel flow per unit of power produced

Question 4

Fuel flow

Answer 4

Units of fuel used per hour

Question 5

Max SAR =

Answer 5

Max SAR = airframe efficiency (or TAS / power) x engine efficiency (1 / SFC)

Question 6

How is max range achieved from an airframe efficiency perspective

Answer 6

By flying at the min drag speed (on a PR curve this occurs where the line draw from the origin of the graph is tangential to the curve)

Question 7

Wind effect on range

Answer 7

Range reduces in headwind and increases in tailwind, in strong headwinds the optimum speed for range is increased and in strong tailwinds the optimum speed is reduced

Question 8

Engine considerations for flying range

Answer 8

Lowest SFC and the best range is achieved by:
- having no more than weak mixture MAP set
- min RPM
- engine is properly leaned
- supercharger in low gear
- a/c at full throttle height
- carb heat OFF + air filter OUT

Question 9

Altitude and Weight effect on range

Answer 9

Altitude has no effect on the best IAS to fly but if weight is increased range is reduced and the best speed to fly is increased