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posted by martyb on Wednesday May 15 2019, @01:20PM   Printer-friendly
from the Ready!-Shoot!-Aim! dept.

What's faster than a speeding bullet? The Dutch F-16 that shot itself.

The Netherlands' Defense Safety Inspection Agency (Inspectie Veiligheid Defensie) is investigating an incident during a January military exercise in which a Dutch Air Force F-16 was damaged by live fire from a 20-millimeter cannon—its own 20-millimeter cannon. At least one round fired from the aircraft's M61A1 Vulcan Gatling gun struck the aircraft as it fired at targets on the Dutch military's Vliehors range on the island of Vlieland, according to a report from the Netherlands' NOS news service.

Two F-16s were conducting firing exercises on January 21. It appears that the damaged aircraft actually caught up with the 20mm rounds it fired as it pulled out of its firing run. At least one of them struck the side of the F-16's fuselage, and parts of a round were ingested by the aircraft's engine. The F-16's pilot managed to land the aircraft safely at Leeuwarden Air Base.


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  • (Score: 5, Informative) by Snotnose on Wednesday May 15 2019, @02:38PM (7 children)

    by Snotnose (1623) on Wednesday May 15 2019, @02:38PM (#843835)

    The bullets slow down due to air resistance, and the geometry of the firing solution can put the plane into the path of the bullets. For example, imagine the plane is flying level and shoots it's gun. The bullets start to drop. Now imagine the pilot drops the nose, so the plane is making a beeline to the path of the falling bullets. The bullets are not only slowing down, they're taking a longer path to the impact point.

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  • (Score: 4, Interesting) by deadstick on Wednesday May 15 2019, @02:49PM

    by deadstick (5110) on Wednesday May 15 2019, @02:49PM (#843842)

    Exactly right. It's a low-probability event, but this is at least the third such incident since the 1950's.

  • (Score: 1, Interesting) by Anonymous Coward on Wednesday May 15 2019, @03:43PM (4 children)

    by Anonymous Coward on Wednesday May 15 2019, @03:43PM (#843864)

    The story said "shells" not bullets. I'm thinking they flew into the expended shells.
    'A bullet is only the projectile. The complete thing is called a round or a cartridge. A shell is a synonym for cartridge.'

    • (Score: 3, Informative) by Anonymous Coward on Wednesday May 15 2019, @04:59PM

      by Anonymous Coward on Wednesday May 15 2019, @04:59PM (#843888)

      'Shell' is also used to refer to a projectile that delivers a secondary payload, such as an explosive. See https://en.wikipedia.org/wiki/Shell_%28projectile%29 [wikipedia.org]
      A quick look at the 20mm Cannon commonly used on the F-16 leaves both interpretations as possible.
      https://en.wikipedia.org/wiki/M61_Vulcan [wikipedia.org]

    • (Score: 2) by RS3 on Wednesday May 15 2019, @07:20PM (1 child)

      by RS3 (6367) on Wednesday May 15 2019, @07:20PM (#843934)

      Makes absolutely no sense. If the shells are ejected (and I wouldn't bet on it) they would slow down almost instantly and be far behind- certainly could not be moving forward.

      • (Score: 1, Informative) by Anonymous Coward on Thursday May 16 2019, @06:24AM

        by Anonymous Coward on Thursday May 16 2019, @06:24AM (#844153)

        A shell is like a bullet, but it can explode. Things above .50 caliber are allowed to be shells. For .50 caliber and smaller it is banned by treaty. It is possible to have a 20 mm bullet, but it wouldn't be done.

    • (Score: 1, Informative) by Anonymous Coward on Wednesday May 15 2019, @09:46PM

      by Anonymous Coward on Wednesday May 15 2019, @09:46PM (#843978)

      Aircraft mounted M61s are typically double-feed, ie spent casings are returned to the magazine.

  • (Score: 3, Informative) by Arik on Thursday May 16 2019, @05:44PM

    by Arik (4543) on Thursday May 16 2019, @05:44PM (#844367) Journal
    "The bullets slow down due to air resistance, and the geometry of the firing solution can put the plane into the path of the bullets. For example, imagine the plane is flying level and shoots it's gun. The bullets start to drop. Now imagine the pilot drops the nose, so the plane is making a beeline to the path of the falling bullets. The bullets are not only slowing down, they're taking a longer path to the impact point."

    Yep. I couldn't find a trajectory chart for the Vulcan, but it's got to have a pretty crappy CoD. It *does* seem to have a respectable muzzle velocity of over 3k fps, at least when fired from a stationary emplacement. In actual fact, if the plane is already going let's say 1k fps when it fires, the muzzle velocity won't be the full 4k you might expect, it will be significantly less, because air resistance is drastically increased by that 700 mph headwind. And the faster a projectile like this starts off (relative to the earth, NOT to the firing plane) the faster the velocity will drop initially. Just as water feels like concrete if you hit it fast enough, air too becomes increasingly inflexible at high speeds.

    And then on top of that, the pilot is increasing his throttle, probably using afterburners, because he's building velocity as quickly as possible in that dive for the moment he pulls back up and escapes the scene. And while the projectile is not very aerodynamic, the plane is, so in addition to adding a great deal of thrust, it's much better at conserving initial velocity as well. So the projectile is rapidly braking while the jet is rapidly accelerating then pulling back up to cross paths with the projectile. It's easy to see how a collision would be possible.

    Cannons are of very limited utility in air to air combat because of this. The rapid deceleration means they're only effective at extremely short range, and the availability of missiles that are effective at far greater ranges makes them a last ditch weapon that's unlikely to be used for a2a against a comparable opponent.

    They can be of great utility for surface attack, of course, but even then if your plane is fast enough you might wind up with an incident like this.

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