Linked Questions
14 questions linked to/from How (and why) does engine thrust change with airspeed?
15
votes
6
answers
7k
views
Why aren't takeoff flaps used all the way up to cruise altitude?
In general aviation aircraft such as Diamond star DA-40, flaps to take-off are used until 500ft AGL and speed before retracting flaps is Vy (best ROC speed)-67kts and after retracting flaps is 80kts.
...
- 1,021
16
votes
5
answers
4k
views
Why is thrust inverse to speed in piston engines?
It is said that piston engines have constant power output, and thus their thrust is inverse to speed (e.g. here), while turbines have relatively constant thrust. I'm looking for an intuitive ...
- 293
12
votes
5
answers
10k
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?
- 121
12
votes
4
answers
5k
views
9
votes
3
answers
6k
views
Why is thrust available constant with speed for turbojet engines, when it varies with speed for turboprop engines?
Similarly, why is power available (nearly) constant with speed for a propeller engine, while it varies for a jet engine?
- 319
9
votes
1
answer
7k
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 ...
- 9,399
9
votes
1
answer
16k
views
How much air, by mass, enters an average CFM56 turbofan engine cruising per minute?
How many kg of air enters an average CFM56 turbofan engine cruising per minute?
I have looked everywhere and cannot find it or figure out how to find it, if you could either tell me or give advice on ...
- 1,211
6
votes
1
answer
3k
views
Why is thrust said to be constant over speed for a jet engine?
I'm just interested in some basic facts regarding flight. On reading the rather "low level" book "Understanding Flight, David F. Anderson, Scott Eberhardt), I recently came up to the ...
- 251
2
votes
1
answer
5k
views
How do power and thrust curves compare?
I would like to really understand why when talking about jets we care about thrust but when talking about propeller aircraft we care about power.
(THRUST)="Just a force"
(POWER)= work/time = ...
- 81
4
votes
4
answers
5k
views
What is maximum acceleration that can be achieved by afterburner in level flight?
I am wondering how a fighter jet (let's take F-22 for example) would compare to other vehicles in terms of acceleration while in flight.
For cars and motorcycles, achieving 0-100 KPH in 2 seconds is ...
- 222
1
vote
3
answers
2k
views
Why does power go up with the cube of the airspeed?
If i have an airplane with over 100 kN of thrust, and i want to accelerate from a velocity at which drag force is 25kN to a velocity twice higher, is it possible that i wont be able to do this because ...
- 2,544
2
votes
1
answer
2k
views
Does jet engine exhaust velocity relative to itself remain constant despite speed changes?
Maybe this is a stupid question.
I seem to have been told, the velocity of the exhaust leaving an airbreathing jet engine relative to the engine, is constant despite changes in airspeed. However, to ...
3
votes
1
answer
2k
views
Why is the thrust-specific fuel consumption much worse for high bypass turbofans at cruise?
General Electric GE90
Takeoff: 0.278 lb/lbf/h (28.3 kg/kN/h)
Cruise: 0.545 lb/lbf/h (55.6 kg/kN/h)
Source: https://en.wikipedia.org/wiki/General_Electric_GE90#Specifications
I assume this is typical ...
0
votes
1
answer
293
views
Is there a graph that shows the thrust required for a given airspeed? [duplicate]
I would like to see the graphical relationship between thrust required and airspeed for a typical general aviation aircraft, e.g. C-150 or C172 series.
- 21