F22 Raptor Shot.

Steyr

What a picture.:)

A United States Air Force F-22 Raptor executes a supersonic flyby over the flight deck of the aircraft carrier USS John C Stennis in the Gulf of Alaska

Picture: REUTERS



http://www.telegraph.co.uk/news/picturegalleries/picturesoftheday/5683850/Pictures-of-the-day-29-June-2009.html?image=4

ronnie3585

I thought someone shot a Raptor.

Cool pic though.

5uspect

That's a pretty cool shock structure. Get out your protractors and figure out the Mach Number!

Silenceisbliss

5uspect wrote: »

That's a pretty cool shock structure. Get out your protractors and figure out the Mach Number!

ha, that was my first thought when I first saw that picture aswell....we're all such nerds....what a fail.

Nforce

5uspect wrote: »

That's a pretty cool shock structure. Get out your protractors and figure out the Mach Number!

My guess is that it isn't going supersonic at all. The shock cone does not necessarily mean an aircraft travelling @ Mach1+.....eg see these pics

5uspect

Nah its a supersonic shock, those pics just show condensation due to the pressure change on the wing. There isn't the clear discontinuity.
Plus the shock structure is forming exaclty as it should.

Captain Chaos

Almost 100% not supersonic. Its very close though, I'd say about M0.96. Even over a USN carrier I don't think they are allowed to go supersonic that low. They are allowed to do supersonic flybys of Navy ships but they have to be in and around 10,000ft as far as I know.

Got that info from a book about F-14 squadrons in active duty over Iraq and Afganistan.

Sleipnir

Captain Chaos wrote: »

Almost 100% not supersonic. Its very close though, I'd say about M0.96. Even over a USN carrier I don't think they are allowed to go supersonic that low. They are allowed to do supersonic flybys of Navy ships but they have to be in and around 10,000ft as far as I know.

Got that info from a book about F-14 squadrons in active duty over Iraq and Afganistan.

+1 The shock waves are oblique to the surfaces they came from. If it was truly supersonic, the shock would be in front of the aircraft.

Still, great shot.

5uspect

Sleipnir wrote: »

+1 The shock waves are oblique to the surfaces they came from. If it was truly supersonic, the shock would be in front of the aircraft.

Still, great shot.

No. If it were M>0.3, i.e. compressible then you would have a curved bow wave in front of the nose. If its transonic M = 1 you will get normal shocks on the wing.
If its supersonic then you get sharp oblique shocks and sudden changes of angle. You would get normal shocks at inlets but not an the geometry you find on an F-22.

A supersonic shock wave is essentially the flow being asked to move out of the way faster than it would like (via pressure waves).
Therefore the shocks are attached.

EDIT for example:

Nforce

Here's another example of a non supersonic vapour cone....

https://www.youtube.com/watch?v=zyCj66JEyJ8

As stated earlier in the thread, the F-22 was not going supersonic.;)

5uspect

Not quite. There are very big differences between your examples and the OP's image.

First of all such a vapour cone formed by low pressure when flow is accelerated over the aircraft. In the near transonic case the wings and even the canopy effectively become supersonic nozzles and generate near normal shocks.



The shape of the base of the cone is a good representation of the lift distribution over the wing. Note that it does not really extend beyond the wing tip, decreasing with span.


In a hard turn or high angle of attack the low pressure over the wing due to high lift also causes vapour but not as sharply, for example from your previous post for the subsonic F-117:


With supersonic flight the shock structure extends significantly beyond the aircraft. It is effectively tearing through the air. The original shot shows the the shocks extend well beyond the lifting surfaces and there are several of them as here:

hexagramer

when i was in the raafc as a kid they used to tell us no pilot was alowd break barriers or endanger the life span of an expensive fighter jet or they face instant dishonorable discharge.

crazy americans