Linked Questions
24 questions linked to/from What is a ramjet?
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Why can't jet engines operate with supersonic air and how do they slow it down?
Typically jets cannot operate when intake airflow is supersonic relative to the engine. Why is this so? Also, why are scramjets able to use supersonic air?
To slow down the air to subsonic speeds, ...
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27
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7
answers
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Why are adjustable area jet engine nozzles mostly limited to military use?
It seems that only jet engines with afterburners use adjustable area nozzles (this means adjusting the area of the nozzle but not necessarily the direction). This includes most fighter jets, as well ...
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20
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2
answers
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How is supercruise achieved?
Wikipedia article tells that supercruise is a condition when an aircraft can achieve velocities above Mach one without using the highly inefficient afterburners. But still, there are not a lot of ...
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5
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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?
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25
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3
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Why are turbofan inlets leaned/angled forward?
(Image Source: Wikipedia)
Seeing that everything is radially symmetric (apart from the nacelle mount, naturally), I wonder why the inlet (the front part of the nacelle) is usually skewed?
- 909
17
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2
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Why would maximum fly-time (endurance) not coincide with max L/D operating point?
This question is motivated by another SE Aviation answer where @Peter Kampf writes the following two useful bits of information:
Aircraft like to fly near their optimum L/D ratio, where drag ...
- 8,436
12
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2
answers
10k
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How (and why) does engine thrust change with airspeed?
I'm interested in how the thrust of a turbofan engine is affected at higher airspeeds (TAS). I know (I believed) that engine thrust(at constant N1) was relatively constant like in the following graph (...
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9
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3
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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?
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4
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Why weren’t large, high-power radial engines built to take advantage of the Meredith effect?
Most aircraft piston engines fall into two general categories:1
Radial engines (radials for short2) have their cylinders radiate out from the crankshaft in a star pattern; they tend to have a blunt, ...
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4
votes
1
answer
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What advantages would a triangular shaped spy plane have over a an SR-71?
This is a picture of the supposed SR-72 Aurora. What kind of advantages would this have over the SR-71, in terms of its triangle design? Paper airplanes have the same shape, and fly really well.
The ...
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1
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2
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Why wasn't a scramjet used for the Concorde?
Why didn't Concorde use a scramjet engine for supersonic flight, but it is used in the Airbus and Skreemr hypersonic flight concepts to achieve supersonic speeds?
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6
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3
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How does turbofan engine performance depend on speed and density altutude?
I am looking at a simulation engine (jsbsim). Their turbine engine simulation requires a function, given by table, of thrust at Mach number and density altitude.
Engine definitions generated by their ...
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6
votes
1
answer
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How does compression ratio change, if at all, from sea level to higher altitudes?
As I understand it, compression ratio is the max pressure inside the engine divided by the ambient air pressure. This is for turbojets and turbofans.
Sea level pressure is about 100 kPa. An altitude ...
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5
votes
1
answer
1k
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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 ...
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5
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1
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Is a subsonic scram-jet reasonable?
By placing a de laval nozzle at the inlet, can the resulting supersonic airflow allow a scram jet to operate efficiently?
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