Endurance, cost index, optimum altitude (01-06-18) Flashcards
What is the speed of long range cruise?
4% faster than max range speed
1.37Vmd
What is cost index?
The ratio of cost of time to cost of fuel
What does a low cost index indicate?
Minimal fuel cost
What does a high cost index indicate?
Minimal cost of time.
What cost index correlates to max range speed?
0
What cost index correlates to Vmo/Mmo?
200(max)
At what speed does lowest total operating costs occur?
MECON
What is the equation for Jet endurace?
Jet E = 1/(SFC x drag)
What is the equation for prop endurance?
Prop E = 1/(SFC x power)
What is the best altitude for high endurance for a jet?
High due to SFC being lower
What is the best altitude for endurance for a prop?
low due to power required being lowest.
What is the best altitude for endurance for a turboprop?
Medium due to SFC being improved at higher altitudes offsetting the increas in power required.
What is the equation which compares fuel flow and aircraft mass for 2 different scenarios?
New fuel flow / old fuel flow = new mass / old mass
What is the optimum altitude?
The altitude for best specific range
Describe a step climb
Where the aircraft flies at the same altitude until 2000ft below the optimum altitude, it then climbs 2000ft above and then flies at that new altitude until 2000ft below again.
