Questions tagged [supersonic]
Use for questions relating to flight at speeds greater than sound and related effects from doing so.
166
questions
15
votes
1answer
3k views
Can a jet stream make a subsonic plane fly at a supersonic speed relative to the ground?
If a plane flies with a jet stream, its speed relative to the ground is the sum of the speed of the jet stream and the speed of the plane relative to the air in the jet stream. If the speeds that are ...
13
votes
1answer
272 views
Could one see stars from the Concorde in daytime?
The Concorde flew to an altitude of 60,000 ft (18.3 km) where stars should be visible at noon, aren't they? This question asks on how high stars become visible, and it is said Blackbird pilots could ...
6
votes
1answer
266 views
Why did the altimeter in an F-16 jump suddenly as it passed through Mach 1?
In this video, Destin — the creator of YouTube channel Smarter Every Day — rides in an F-16 with a USAF Thunderbirds pilot. If you start watching the video at the 11:06 mark, you will see what happens ...
0
votes
0answers
76 views
What happens when a “ground effect” plane approaches the sound barrier?
Does the shock wave inhibit or contribute to lift? What is the ideal speed to fly near or on the speed of sound while using the ground effect?
1
vote
0answers
65 views
Why does drag coefficient decrease with Mach number in the supersonic regime?
I'm trying to understand why the drag coefficient decreases in the supersonic regime with Mach number. While it is easy show this using supersonic, potential flow theory, I'm looking for a more ...
1
vote
2answers
92 views
Why doesn't a wing in supersonic flow produce a shock that results in flow parallel to the leading edge?
When we look at a wedge in supersonic flow, a shock emanates from the leading edge such that the flow after the shock is turned and is parallel to the airfoil surface.
The shock angle is based on the ...
1
vote
1answer
68 views
How does wing shape impact shock structure?
I am trying to understand what the 3D shock structure would be for a wing in supersonic flow. Suppose we have a wing which is made of double-wedge airfoil cross-sections.
If we view the shock ...
2
votes
1answer
97 views
Does an airfoil in supersonic flow have zero circulation?
In incompressible flow, the Kutta-Joukowski theorem can be used to relate the lift (per unit span) to the circulation around an airfoil. However, if we look at an airfoil or the flat plate (see below) ...
12
votes
2answers
1k views
Why does directional stability decrease at supersonic speeds?
As an aircraft accelerates through the transonic region from full subsonic to to full supersonic flow its directional or yaw stability decreases. What causes this reduction?
0
votes
1answer
172 views
Could an arrow planform be better for a supersonic aircraft than a delta? Why?
From this review paper
Page 11:
Strut-bracing for the SST allows very signi®cant
reductions in both vortex and wave DDL via an extreme
arrow con®guration and could be favourable to LFC via
...
1
vote
1answer
164 views
Would supersonic bi/tri/multiplane wings have less lift interference drag than a subsonic version?
Biplane wings interfere with each other, reducing the total lift often to about only 20% more than a mono wing of the same chord and span.
But at supersonic speeds - say, Mach 2, where Mach angle is ...
1
vote
1answer
131 views
What is the speed above which painting an aircraft black (or dark) results in lower skin temperature?
The Concorde is painted white for thermal reasons. If I understand correctly, it is done to reflect as much radiation as possible in order to lower tempereture. But when the skin is really hot (SR-71, ...
1
vote
0answers
52 views
How to avoid shock (particularly Oblique shock) inside Cd nozzle?
Using the Area ratio (A/A*) and for the desired exit Mach number I have designed a cd nozzle. The Inlet total pressure (Po) and the total temperature (To) is calculated using Isentropic relations for ...
2
votes
1answer
114 views
How hot is supersonic intake air?
How hot is the air at the compressor inlet at supersonic speed? For instance the Concorde at mach 2.2 or other jet engines at even higher speeds.
2
votes
1answer
111 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 ...
0
votes
1answer
66 views
How to identify shock waves and expansion waves on a representation of the mach number?
This image is a representation of the Mach number for $M_{\infty}=2.0$
I am very new to CFD and high speed aerodynamics. I'm trying to analyse this image, specifically to understand why the velocity ...
0
votes
0answers
54 views
Why do supersonic and hypersonic planes have a pointed nose whereas commercial planes have a round nose [duplicate]
We see supersonic and hypersonic planes having a pointed nose whereas commercial planes have a round nose.is there aerodynamic reason for these different design?
1
vote
2answers
162 views
Which 2-seat 4th generation fighter/engine/configuration (de-militarized) would the best supersonic long-range civilian private transport?
Seeing recently -with some surprise- that former military jets of fairly recent vintage can be bought e.g. here and operated by (skilled+licensed²+rich³) private individuals after all classified/...
5
votes
2answers
173 views
Why do shockwaves progressively move aft as speed increses?
As an airfoil moves from subsonic to supersonic, the shocks that develop over the surface move progressively toward the trailing edge. What is the physical explanation for this behavior?
As a side ...
3
votes
2answers
372 views
What are the aerodynamic design principles behind the “supersonic” propeller of Luigi Colani's C-309 racing plane?
One of Luigi Colani's designs that is particularly confusing to me is the second design iteration of the C-309 propeller racing airplane. Allegedly, its two propellers are designed to be supersonic ...
2
votes
3answers
321 views
Is it possible to use refrigeration technology to cool the skin of supersonic aircraft?
The fastest air breathing aircraft, the Blackbird SR71 flew at speeds above Mach 3. Its engines could achieve much higher speeds but were limited by the aircraft's skin which would melt due to ...
3
votes
1answer
234 views
Concorde thrust reversers engaged on parked aircraft, but not all engines?
Am I correct in interpreting this photo as showing one thrust reverser engaged, while the other is open? Do the thrust reversers fall into place on a fully powered down Concorde? Could this be caused ...
2
votes
3answers
208 views
Where to find NACA 65-110 Airfoil? [closed]
I'm working on a research project regarding the Bell XS-1, which used the NACA 65-110 airfoil. I haven't been able to find any data on this airfoil, and I'm wondering if anyone knows where I could?
4
votes
2answers
577 views
How can an aircraft travel faster than speed of sound without breaking the sound barrier? [duplicate]
An excerpt from the BBC article here https://www.bbc.co.uk/news/uk-england-london-51433720
"Despite travelling faster than the speed of sound the plane would not have broken the sonic barrier as it ...
4
votes
1answer
98 views
Why is wave drag non-zero for a flow without shockwaves?
Wave drag is often defined as the component of drag that arises due to the presence of shockwaves. Shocks result in an entropy rise and a corresponding increase in drag. However, when using Supersonic ...
5
votes
1answer
219 views
How does a delta wing deal with supersonic boundary separation?
The question Why most of the supersonic or fighter aircraft use all-moving control surfaces? emphasis the importance of all moving stabilator for supersonic aircraft.
Many supersonic aircrafts ...
4
votes
1answer
174 views
What is the physical-based/theoretical reason why supersonic area ruling works?
Supersonic area ruling is used to reduce the drag rise that occurs as aircraft pass through the transonic regime. While it has been validated experimentally, what is the theoretical/physics-based ...
0
votes
1answer
111 views
About ramjet efficiency in supersonic speed. Is there an optimal speed?
I know there is an optimal speed for ramjet.
This are the results of my research.
The reason the efficiency increases with supersonic speed to an optimal value then decreases is related to the ...
8
votes
1answer
111 views
Since shock waves have non-negligible viscosity, why do the normal shock relations ignore friction/viscosity?
The normal shock relations (seen below) are derived by using steady, 1D, neglect potential, no shaft work, adiabatic and zero viscosity assumption. However, since shock waves are "thin regions of high ...
1
vote
0answers
88 views
Supersonic propellers for supersonic aircraft? [duplicate]
A propeller is a spinning wing. Supersonic wings work. So, provided that the blades are made wide-chord and thin like supersonic wings are, with a supersonic airfoil, can they not power efficiently a ...
5
votes
3answers
381 views
Do afterburners use excessive amounts of fuel?
The purpose of an afterburner is to provide additional thrust, and it is obvious that more fuel is needed for that.
But that is to be expected independent of an afterburner. That more thrust needs ...
18
votes
6answers
6k views
Is an afterburner louder than the same jet engine without it?
I would speculate that an afterburner increases the noise because it is nearer to the exhaust. But it certainly causes so many changes in the exhaust flow that it could be less loud as well. It may ...
10
votes
1answer
5k views
Will you be able to hear a supersonic aircraft flying away from you?
I'm wondering if you could be able to hear the sound emitted by an aircraft say traveling at Mach 2 away from you.
I wondered if it might shift the emitted frequencies beyond the audible range. Would ...
-2
votes
1answer
167 views
Is the “Boom” project vaporware or really going to happen? [closed]
Is this https://boomsupersonic.com viable or more vaporware?
Any solid information?
3
votes
0answers
117 views
What will happen to wing Vortices on supersonic aircraft?
Having looked at the new Aerion AS2 design I wondered whether anyone could tell me what happens to wingtip vortices at a cruise of Mach 1.4 with the strange wing shape of the AS2 design? I know that ...
3
votes
1answer
363 views
Why doesn't Concorde stall when passing Mach 1, where a normal airliner does?
As Jay Carr asked: What is a high speed stall?, Jan Hudec explained:
A difference from normal stall is that after supersonic flow separation the lift remains proportional to angle of attack and so ...
10
votes
2answers
3k views
How can an F-22 Raptor reach supersonic speeds without having supersonic inlets?
The F-22 Raptor and some other jets do not have inlet spikes, yet they are able to achieve supersonic speeds. How is that possible?
20
votes
4answers
5k views
Was the Boeing 2707 design flawed?
The mach 2.7 capable Boeing 2707 has an interesting design. I'm curious if there has been any studies done that concluded that this aircraft would simply not have worked, given the way it was ...
52
votes
3answers
12k views
Can you feel passing through the sound barrier in an F-16?
Is it possible for the pilot to feel passing through the sound barrier in an F-16?
What about other modern aircraft, will you feel anything? Do you need to go back to really dated designs before you ...
4
votes
1answer
134 views
How do a narrow airframe and canards keep supersonic shock waves from coalescing?
In a follow up to my previous question: How does the X-59 acheive quiet supersonic flight?
Canards and a long narrow airframe were cited as design choices to prevent shock waves from coalescing. How ...
2
votes
1answer
229 views
How does the X-59 acheive quiet supersonic flight?
By what mechanism or combination of mechanisms does the X-59 reduce the noise produced by a sonic boom? What are the design choices that lead to quiet supersonic flight? I really want to understand ...
15
votes
2answers
953 views
Acceleration of a supersonic aircraft after breaking the sound barrier
People on the physics stackexchange recommended I ask here, so I am pasting my question regarding supersonic aircraft.
I stumbled upon an interesting plot; in particular, the dependence of wave drag ...
4
votes
1answer
492 views
Could the Olympus 593 have been windmill-restarted during supersonic flight?
The Rolls-Royce/SNECMA Olympus 593 (which powered the Concorde) used a complex intake-ramp system to improve the engine's efficiency and prevent an engine shutdown or failure during supersonic flight ...
4
votes
1answer
203 views
Aerospike nose cones for supersonic jets?
Not to be confused with aerospike nozzles. This is about the big pin-like rod in front of ICBM nose cones.
This answer (from Space) about aerospike nose cones notes that one of the potential ...
11
votes
2answers
947 views
How is the camera positioned for these plane-to-plane Schlieren images of shock waves?
These two popular press articles discuss the use of schlieren photography to image shock waves of jets during flight using a special schlieren camera on a third plane.
Gizmodo: NASA Captures First-...
2
votes
1answer
72 views
Are there any special considerations involved in designing manual flight controls for supersonic/hypersonic aircraft?
What things, if any, might need to be taken into account in the design of manual flight controls for supersonic or hypersonic aircraft that wouldn’t need to be taken into account with manual controls ...
4
votes
1answer
213 views
How does a weak shock-wave boundary-layer interaction create wave drag (other than through direct shock losses)?
I'm trying to understand the physical cause of wave drag, beyond the simple statement "the presence of shockwaves increases the drag".
As far as I understand, in the case of a weak BLSWI (so without ...
23
votes
2answers
3k views
Could anyone (non-military) in the present day “exceed mach 1 over a regulated area”?
There is a question What would happen if I exceeded mach 1 over a regulated area?
I wonder, could anyone in civil aviation (not military) actually carry out this violation? I know there are privately ...
4
votes
4answers
708 views
What would happen if I exceeded mach 1 over a regulated area?
What would happen if I exceeded mach 1 over a regulated area? Are there any penalties in place for this violation?
Would ATC actually know I’m flying supersonic or would they have to go out of ...
-5
votes
1answer
369 views
Can electroaerodynamic propulsion be used to circumvent sonic booms?
MIT researchers have created and flown the first plane that doesn’t require any moving parts.
“Although it is still a long way off from commercial gas turbine
propulsion … electroaerodynamic ...
