Message posted by Chris McDowell on January 09, 2007 at 16:50:27 PST:
I started a new topic, because the original one is a ways down the page now. Earlier, The Major was asking if there was a max speed beyond which the F-22 (or presumably any other fighter) could fire its M-61 cannon. The prevailing sentiment in the thread was that at a high enough speed, the Raptor risked running into its own shells (bullets). But hang on a second. Is the Raptor that fast? According to FAS.org, the muzzle velocity of the rounds fired from the M-61 is 3,450 feet per second. Now, assuming my math is correct, that translates to a little more than 2,350mph. Since Mach 1 is about 750mph, that gives the rounds from the cannon an initial speed of approximately Mach 3.1, significantly faster than even the most optimistic appraisals of the Raptor's top speed. True, as Dave Bethke pointed out, the bullet's speed starts dropping as soon as it leaves the gun. So, I suppose there could be certain flight envelopes where this situation (hitting your own shells) is remotely possible, but I would say it's incredibly unlikely. And at any rate, there's no reason the Raptor (or any other fighter) would be firing its cannon at the extreme top end of its speed capability. Therefore, my answer to the question, "Is there a speed beyond which the Raptor can't use its cannon?" would be: No, not in any situation where the cannon would be called for. Just my 2 cents, of course. Chris M.
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