Linked Questions

36
votes
4answers
14k views

Why do gases in the combustion chamber only flow one direction to the gas turbine in a jet engine?

As far as I know from the working principle of jets engines, compressed air in the combustion chamber (or combustion canister) is mixed with fuel. The ignited mixture expands backwards to turn the ...
17
votes
5answers
8k views

Why do most military aircraft use different engines than commercial aircraft?

Why do most military aircraft and helicopters use different engine technology (fighters, B52, U2, etc) than most commercial aircraft? [I removed the use of axial terminology]
31
votes
2answers
12k views

Why does afterburner exhaust have “pulses”?

Instead of being consistently-dense, the afterburner exhaust looks "pulsed" in these pictures below. Is this a trick of the camera, a natural result of interaction with the air, or is there some ...
29
votes
2answers
5k views

Are the fastest moving pieces of a jet engine supersonic?

A jet engine is composed of fast moving pieces. Those pieces are moving into an airmass different form the ambient airmass the aircraft is flying into. The turbine pieces are spinning quite fast, ...
16
votes
2answers
19k views

Why do military turbofan engines use a low bypass ratio?

I know that the most civilian engines use a high bypass ratio which is good for fuel economy and noise reduction. What prevents military engines from using the same technology instead of opting for ...
11
votes
4answers
3k views

What is a ramjet?

What is a ramjet? Was it used on the SR-71 Blackbird?
10
votes
5answers
6k views

Can a convergent nozzle be used for a supersonic jet engine?

Can a supersonic fighter incorporate a convergent nozzle or does it always have to be a convergent-divergent nozzle?
15
votes
2answers
5k views

What is the significance of the speed of sound to aerodynamics and aircraft design?

Almost every aspect of flight seems to be affected by the speed of sound, somewhat in the same way that nearly everything in physics is determined by the speed of light. Obviously it's not exactly ...
15
votes
2answers
1k views

What are the differences between pre-transistor and transistor era jet engines?

What are the differences between pre-transistor and transistor era jet engines? Towards the end of the second world war, most of the air powers had started development on jet engines. From what I ...
8
votes
1answer
5k views

How does a supersonic jet engine differ from a subsonic jet engine? [duplicate]

All jet engines have the same method of air flowing into the engine, which is compressed and ignited. What can engine designers do to make an engine design create more thrust? For example, what is ...
13
votes
2answers
762 views

Is there a surface of a commercial jet exposed to air flow at speed near Mach 1?

With commercial aircraft flying slightly above Mach 0.8, is there any surface exposed to speed of air significantly larger, e.g. near Mach 1? ignoring: The engine components, The boundary layer as ...
4
votes
1answer
430 views

How does the EPR reading behave in reverse, and in reheat modes?

Will an engine pressure ratio indicator (EPR) show the same at full mil thrust as with full reversed thrust? What does the EPR indicate at afterburner active? Will it just show the same as for max mil ...
3
votes
1answer
487 views

How does a wing mounted jet engine on a supersonic airplane prevent the interference in the flow due to Shock? [duplicate]

Wing mounted jet engines face the free stream at Mach number 1 or above, and they work perfectly for Mach numbers below 1 as well, even though the free stream characteristics change a lot after Mach 1....