When new engines are designed for aircraft (military or civilian) they undergo high altitude testing (especially the military ones).

What is high altitude testing of engines? How is that important?


1 Answer 1


High altitude means low air density. Ignition is harder to achieve with lower density, and the size of the combustor determines up to which altitude and throttle setting an engine will stay lit. Testing that it really works at those low densities before flying is a really good idea.

  • 2
    $\begingroup$ ....and also explores the altitudes at which an engine re-light is possible. $\endgroup$
    – Simon
    Jul 8, 2015 at 11:30
  • $\begingroup$ Do they actually have to mount the engine to a test-bed plane and fly it at high altitude, or can they simulate the altitude in a test chamber on the ground? Or should I ask a new question? $\endgroup$
    – FreeMan
    Jul 8, 2015 at 12:09
  • 3
    $\begingroup$ @FreeMan: Both! Initially the test chamber is used, but later a multi-engined plane will carry one of the new ones aloft. $\endgroup$ Jul 8, 2015 at 13:52

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