Questions tagged [transonic]

Use for questions related to the transition between subsonic and supersonic flows, like flight at speeds close to Mach 1 or supercritical wing design.

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Is the highly optimized high subsonic cruise airfoil less safe for higher AOA flight? [duplicate]

An examination of the 737 airliner wing profile and that of a blue whale leads to the question of whether the high Reynolds number subsonic cruising airfoil and the low speed, high AOA airfoil are ...
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136 views

Do any aircraft mach-tuck upwards?

Mach tuck is a change in pitching moment experienced by many aircraft when they fly at transonic speeds; it occurs due to the formation of areas of supersonic airflow, with attendant shockwaves, when ...
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1answer
301 views

Why do 20-series Learjets have such an extreme susceptibility to mach tuck?

Mach tuck is a change (usually nosedown) in an aircraft’s pitching tendency during transonic flight relative to its pitching tendency in below-transonic flight, caused by the appearance of areas of ...
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321 views

Why does transonic drag happen?

I have heard of transonic speed and it is between supersonic and not supersonic. What is it and why does it happen to aircraft and how does it produce a lot of drag. How do you prevent it from ...
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1answer
129 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 ...
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2answers
471 views

Transonic buffet - reason for a rapid movements of the shockwave along the wing chord line?

I know that transonic aerodynamic buffet is caused by the separated turbulent boundary layer striking the airframe (horizontal stabilizer, wings, fuselage) with considerable force causing a high ...
6
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1answer
487 views

Why do some Mach trimmers move the elevator?

A pop-up rod on a the FO's control column on a DC-9 that shows the Mach trim position. (YouTube) Regarding the title, I'm not sure if it's just some or all jetliners (I tried to research it). On the ...
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1answer
285 views

Are there any airliner crashes that can be definitively attributed to Mach tuck?

Mach tuck (the tendency of aircraft to develop an increasingly nose-down pitching moment at speeds above its critical mach number) caused a number of crashes of high-speed fighter aircraft before the ...
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0answers
419 views

What aircraft has the highest critical Mach number?

What aircraft has the highest critical Mach number? The highest I heard of was BAC/English Electric Lightning at Mach 0.95. Are there planes with higher Mcrit. and is it plausible to go higher than ...
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1answer
101 views

What is the ideal volume distribution for minimization of transonic drag?

I am aware what the area rule states - my question is what is defined as "as smooth as possible area distribution" - Is there a formula for the curve?
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2answers
2k views

What are the effects of shockwaves on normal and supersonic aircraft?

What are the effects on the speed of the plane, does it effects the body of the plane, and do shockwaves cause major damage to the plane. I know that flying at Mach 1 is really risky, but what's the ...
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1answer
728 views

What's the relationship between drag divergence Mach number and maximum operating limit Mach number?

The drag divergence Mach number, also known as the force divergence Mach number, is the Mach number where drag waves start to form. The drag divergence Mach number is typically between 5 to 10 ...
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339 views

Can a transonic airfoil have two shock waves?

I am currently running CFD cases on a transonic airfoil at Mach 0.75 and performing an angle-of-attack sweep to evaluate its performance. When I reached the angle of attack of 4.5 degrees (which I ...
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2answers
802 views

Is it possible to hear a sonic boom when the aircraft is exactly at Mach one?

Will an observer on the ground hear a sonic boom if a plane passes overhead at exactly the speed of sound? That is, the plane does not cross the sound barrier. The plane just hits Mach one - and ...
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2answers
943 views

Does the sound barrier apply to a silent aircraft? [duplicate]

For my summer duty, I was looking at the sound barrier effects with a glimmer of hope to understand them: "A supersonic aircraft is one that can travel faster that the speed of sound. As the plane ...
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221 views

What would the density profile of this shock wave look like, roughly?

The YouTube video titled Shock Wave Formation in Transonic Flight shows a hand-held video of a visible shock wave extending from the top of a jet engine near the front. The shock wave is visible by ...
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535 views

How does airfoil thickness affect the Mach number at which it experiences transonic flow?

Roskam (book: Airplane Aerodynamics and Performance, Subparagraph: 2.5.2 HIGH-SPEED AIRSPEED INDICATORS (COMPRESSIBLE FLOW)) affirms: [...] Airplane with no sweep and thick airfoils become ...