Answer some advanced propulsion questions. Describe what you would go through if
ID: 1816593 • Letter: A
Question
Answer some advanced propulsion questions. Describe what you would go through if you sat on a volume of air as it traveled through an afterburning turbojet engine (aside from vertigo and severe burns). Challenging. What limits the altitude at which a jet engine may fly? What could happen if you flew too high? (I mentioned this in lecture a couple of times - it is very bad from a performance point of view.) More challenging. What are the advantages of having multiple spools in a turbo fan engine? (It is related to the behavior of the fan. Think of it as comparable to a big propeller... and how the flow changes as it pass through the core.)Explanation / Answer
(b) As aircraft climb to higher altitudes, the air outside gets thinner. The actual equation for the change in pressure with altitude gives an exponential rather than linear decay. This is essentially because air is squashable so is compressed together at lower altitudes. Therefore pressure is decreased more rapidly near the ground than at higher altitudes.