Flight at high altitude
From NPrize
Flight at high altitude
Some information is summarized in the main page already, in the aircraft section.
Gas properties and altitude
Density is used to calculate lift of an wing and thrust of an engine amongst other. We need to know what air densities will be faced in order to design everything.
Atmospheric density depends on pressure. This table gives atmospheric pressure and temperature depending on altitude. We can see that a tenth of ground atmospheric pressure is met at around 16km altitude, and a hundredth of it at around 31km altitude.
Approaches overview
High engine power at low air density
Is it possible to have a low total pressure ratio engine operating at subsonic inlet speeds? The MiG 25 has supersonic inlet, which allows him to have a significant pressure increase before the compressor actually gives energy to the flow.