Timeline for How (and why) does engine thrust change with airspeed?
Current License: CC BY-SA 4.0
10 events
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| Mar 28, 2019 at 6:17 | comment | added | Peter Kämpf | @AbanobEbrahim: Yes, that is correct. For the nitpickers: The actual numbers might vary a bit between the different scenarios. | |
| Mar 27, 2019 at 23:24 | comment | added | Abanob Ebrahim | @PeterKämpf: Thank you. I'm new here on Aviation and I already admire your awesome answers. But just to make sure I understand you correctly, let's assume the exhaust velocity when the engine is stationary is 500 $m/s$. Now by approx. constant you mean that when the aircraft is moving at 200 $m/s$, the exhaust speed relative to the aircraft is still 500 $m/s$ but to someone standing on the ground the exhaust speed is just 300 $m/s$ in the opposite direction of the aircraft. So is that correct? | |
| Mar 27, 2019 at 22:01 | history | edited | Peter Kämpf | CC BY-SA 4.0 |
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| Mar 27, 2019 at 22:00 | comment | added | Peter Kämpf | @AbanobEbrahim: Yes, very good question! The exit speed is approx. constant relative to the aircraft, so this puts an upper limit on the maximum speed which can be achieved. | |
| Mar 27, 2019 at 17:56 | comment | added | Abanob Ebrahim | @PeterKämpf when you said $v_{exit}$ is almost constant, is it constant relative to the aircraft so when the aircraft accelerates the exhaust velocity actually decreases relative to someone standing at the ground? or do you mean that the exhaust velocity is constant regardless of how fast the aircraft is going and so it actually increases relative to aircraft? | |
| Feb 25, 2019 at 6:18 | comment | added | Peter Kämpf | @Talisker: Yes, supersonic means more than the speed of sound of this hot air. There are supersonic aircraft with subsonic engine exit speed, and that only works because of the higher speed of sound in hot air, but those are the exception. | |
| Feb 24, 2019 at 22:04 | comment | added | Talisker | Just to clarify, by a turbojet's exit speed being "supersonic" is that meaning within the exhaust (with a higher speed of sound because it's hot) the actual flow is supersonic, or is it subsonic but faster than the speed of sound in the surrounding air? | |
| Mar 30, 2018 at 14:43 | vote | accept | Darjan | ||
| Mar 29, 2018 at 21:33 | history | edited | Peter Kämpf | CC BY-SA 3.0 |
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| Mar 29, 2018 at 21:19 | history | answered | Peter Kämpf | CC BY-SA 3.0 |