Altitude and efficiency
All,
Probably one you have all been asked at some point and an old favourite for selection interviews - the question of why do aircraft, especially jets, fly so high.
I am currently embarking on a number of selection interviews, and have researched the topic, but would like to see what some of you experienced guys make of my reasoning.
Basically, I gather that as an aircraft climbs into the rarefied atmosphere holding a constant airspeed, the true airspeed of the aircraft increases. Thus, by flying at FL370 (or whatever), you are effectivly travelling a lot faster than you would at a lower altitude for a given thrust setting.
Also, the amount of thrust required to hold a given IAS increases with altitude. Thus, this allows the EPR's to be set higher, and at higher RPM, the turbines operate more efficiently.
Am I heading in the right direction or will I make a fool of myself?? Thanks for taking the time to read this (if anyoine has!!)
Cheers
Cuban