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Now that is what I call a clever photograph

· Aerospace & Astronautics · Science & Technology

A US stealth aircraft, photographed while breaking the sound barrier. I don’t know why, given that Man has achieved the feat of breaking Mach 1 for more than half a century since the great Chuck Yeager officially did it first, but stuff like this still gives me a buzz.

May 13th, 2009 |

10 comments to Now that is what I call a clever photograph

  • Bruce
    May 13, 2009 at 2:45 pm

    particularly since the B-2 isn’t supposed to be supersonic-capable.

  • Cleanthes
    May 13, 2009 at 4:03 pm

    I call bollocks on this. Close to transonic, possibly, but not supersonic – the most cursory inspection says it doesn’t have anything that would allow it to fly supersonic (wings swept back to be inside the shock cone, fully moving control surfaces etc)

  • Bod
    May 13, 2009 at 5:05 pm

    I’d defer to someone like Dale on this one, but my understanding is that the P-G singularity is cone shaped (as alluded to in the article), … like this … and it is initiated at the nose of the craft and rolls back, rather than in the more diffuse manner observed in the still at the Telegraph’s site.

    Still – a cool shot and much better value for money than a 747 buzzing the public in downtown NYC.

  • Marc Sheffner
    May 14, 2009 at 7:23 am

    Is it legal to take this kind of photo? Is legal to publish it? Is it legal to look at it? !?! Who’s that knocking on my door?? It wasn’t me!!!

  • TomC
    May 14, 2009 at 10:11 am

    You often see effects such as this at airshows, where aircraft are travelling nowhere near the speed of sound. Hard manoevering accentuates the effect, and high angle of attack climbs will produce an impressive “vapour ring” around the mid section of the aircraft. Tails and vortices come off the wingtips like smoke trails.

    Very impressive, but not connected with supersonic shock waves IMHO. I believe it is due to air of a certain level of humidity being subjected to temporary pressure changes, whereby an airofoil lowers the pressure to condensation point in passing, whereupon the revertion to ambient pressure causes the condensation to disappear as fast as it formed, giving the “cloud” the permanency of an optical illusion.

  • heat
    May 14, 2009 at 1:32 pm

    Tomc is probably correct. Anyhow they are not allowed to break the barrier at low altitude over a built-up area.

  • Laird
    May 14, 2009 at 2:18 pm

    FWIW, the caption to the photo does say “high subsonic speed”.

  • David Gillies
    May 15, 2009 at 12:15 am

    A Prandtl-Glauert singularity is a phenomenon whereby a wave of rarefaction and compression passes through a compressible medium such as air, causing its dew point to fall momentarily below ambient. Water vapour then condenses and becomes visible. It’s easier to produce this effect in the transsonic region, but it can occur at much lower velocities. It helps if the air is very humid as then its dew point is higher.

    Maximum speed of a B2 is about Mach 0.95, although cruising speed is about that of a 747.

    Most impressive thing about the B2? It can fly a single pass over a target and from ten miles up and twenty miles downrange, completely invisible to radar, release eighty 500lb bombs, all of which are aimed at a different target, and all of which will land within 30 feet of their aimpoint.

  • Kim du Toit
    May 15, 2009 at 2:02 pm

    “It can fly a single pass over a target and from ten miles up and twenty miles downrange, completely invisible to radar, release eighty 500lb bombs, all of which are aimed at a different target, and all of which will land within 30 feet of their aimpoint.”

    As usual, David has the truth of it. Top speed is only impressive in drag racing, and the speed of sound is simply a milestone.

    But destroying bad guys in secret, with pinpoint accuracy… hubba hubba.

    It is, after all, a military aircraft.

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