Questions tagged [jet-engine]

Engines which propel aircraft via "jet propulsion", i.e. by expelling high-velocity gasses (usually primarily air) through propelling nozzles.

Jet engines are engines which propel aircraft by jet propulsion, ejecting high-velocity exhaust gasses through propelling nozzles to generate thrust that moves the aircraft. In common use, the term refers specifically to airbreathing jet engines, which require a continuous supply of outside air in order to function. The most-commonly-used types of jet engine are the (including the ) and ; the and are much less common, and seen almost exclusively on and/or aircraft. Other, rarer types include the , which is unusual in that it uses pulsed (rather than continuous) combustion, and is generally only seen on unmanned aircraft, and the , a very early type of jet engine which is mainly of historical interest.

Jet engines are commonly found on transport-category airliners, as well as many corporate aircraft.

More information on jet engines can be found on Wikipedia.


Related Aircraft Propulsion Tags

  • for reciprocating engines, usually gasoline powered. Mainly used on light aircraft.
  • for turbine engines which drive a propeller to generate thrust rather than using jet propulsion.
  • for turbine engines which are used to provide electrical, hydraulic, and/or pneumatic power, rather than directly for propulsion.
  • for engines which carry an onboard supply of oxidizer in addition to fuel, and do not need to take in outside air.
946 questions
37
votes
2 answers

Why should jet engine throttles be moved smoothly?

On the only jet engined aircraft I'm trained on, the Bell 206B (Allison 250 engine), I was taught to move the throttle slowly and smoothly, especially when opening. I've also see this done with Rolls Royce testing RB211s and early Trents. I've…
Simon
  • 31,213
  • 4
  • 141
  • 163
36
votes
2 answers

Jet engines: are they owned by the airline or just rented?

For commercial jets, the engines are complex parts of the aircraft, are the most expensive components, and must be carefully maintained. Source When a company buys an aircraft, do they also own the engines, or are they still the property of the…
mins
  • 72,728
  • 27
  • 308
  • 441
35
votes
6 answers

On which point(s) in a jet engine does the reaction force act?

Turbojet and turbofan engines are part of a family of engines referred to as reaction engines to emphasize the fact the aircraft is pushed forward mostly by Newton's 3rd law of motion when gases are accelerated. Diagram of a turbofan jet engine,…
mins
  • 72,728
  • 27
  • 308
  • 441
33
votes
4 answers

Why do jet engines smoke?

(YouTube video) From the video linked above, I was wondering why the engines emit so much smoke? Has something gone wrong? Poor maintenance? Isn't it dangerous?
Fabrizio Mazzoni
  • 9,882
  • 15
  • 64
  • 113
29
votes
2 answers

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, thus its blade tips may be moving at a supersonic…
Manu H
  • 16,468
  • 25
  • 101
  • 210
26
votes
4 answers

If jets carried pure O2 to use for combustion, would they be more efficient?

Air is around 21% Oxygen. The bulk of air is non-flammable Nitrogen. Wouldn't surrounding the jet fuel with only O2 create more efficient and clean combustion?
Jon Rausch
  • 271
  • 3
  • 4
25
votes
7 answers

Are German, Japanese, and Chinese companies not able to build aircraft jet engines on their own?

As far as I know, only 4 countries can build aircraft jet engines on their own: USA {GE, P&W} Russia {Klimov, NPO Saturn} France {Safran} UK {Rolls-Royce} All other countries use jet engines bought from companies of these 4 countries. Is that…
user8792
16
votes
3 answers

Do the design and manufacturing of cruise missile engines and aircraft jet engines require the same amount of efforts?

Cruise missile engines are relatively smaller in size. However, they might need the same level of expertise e.g. metallurgy, single-crystal blades, etc. Do the design and manufacturing of cruise missile engines and aircraft jet engines require the…
user366312
  • 868
  • 1
  • 5
  • 20
16
votes
5 answers

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]
jwzumwalt
  • 11,461
  • 8
  • 52
  • 91
16
votes
1 answer

What is this on the aft end of this GEnx engine?

In the next picture, corresponding to a GEnx engine, what is the item circled in red? Thank you very much again.
XF-91
  • 2,096
  • 2
  • 24
  • 32
16
votes
5 answers

Why do some fighters have two engines and other have only one but still give the same performance?

The F-16, F-35, and Gripen have single engines. On the other hand, the Ching-kuo (Taiwan) and F/A-18 have double engines, but the combined thrust of two engines is almost equal to the single engine thrust. Why do some aircraft use double engines?
user8792
15
votes
6 answers

How does jet engine water injection work?

How did the "wet takeoff" of old days work? Was the water used ordinary distilled water, or did it have additives? Where is it carried in the aircraft?
Germano Cavalcanti
  • 323
  • 1
  • 2
  • 8
15
votes
1 answer

What is the lifespan of an airline engine?

As per subject, what is the lifespan of a jet engine? Do they have a fixed hours which they can be used and regardless of the state have to be exchanged or are they serviced and maintained until they are deemed not good for use? If they do have a…
Fabrizio Mazzoni
  • 9,882
  • 15
  • 64
  • 113
15
votes
2 answers

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 understand, all of this predated any practical…
Eric Urban
  • 1,596
  • 2
  • 11
  • 23
13
votes
6 answers

What is the relationship between thrust and engine RPM in a turbojet?

I understand that, to increase the thrust of a turbojet engine in flight, it is necessary to increase fuel mass flow rate. This throttling then increases the exit velocity of air and gives increased thrust (if this was wrong, please also explain how…
Raj
  • 2,088
  • 3
  • 22
  • 28
1
2 3 4 5 6 7