muller@gn.ecn.purdue.edu (Mark B. Muller) (04/11/90)
From: muller@gn.ecn.purdue.edu (Mark B. Muller) >From: bowersr@urubu.cs.orst.edu (Robert Mark Bowers) > >Besides increasing bullet mass, the hardness of DU recommends it as bullet >material. >The earlier reference to "kinetic energy" is not quite sound. The >kinetic energy of any projectile shot from a gun is determined more by the >amount of powder used (and its burning characteristics) than by the mass of the >bullet: Given identical powder charges, identical guns, and two projectiles >of identical shape and size, the kinetic energy imparted will be identical. >Note that the mass of the projectile doesn't affect the kinetic energy; if one >of the projectiles was heavier than the other, it would have a lower muzzle >velocity, in keeping with the one-half mv squared formula from elementary >physics. >I've already referred to DU's hardness, but I'm surprised nobody's mentioned >it before: What good is a soft penetrator? That DU rounds can pass all thess >way through a tank is due as much to DU's hardness as to its density. The importance of the mass is that it allows the penetrator to have a smaller cross section for the same amount of mass. This gives the round decreased air resistance, so that it will "carry" better, and it also will impart the same amount of kinectic energy over a smaller area of the armor, which increases its ability to penetrate armor. Its hardness allows it to be used at velocities which would shatter steel, so that the penetrator can be made actually lighter than a conventional one, by making it less than the full diameter of the gun barrel. Of course, all of this is also true of tungsten when compared to steel; it is just that the uranium does an even better job than tungsten. *-------------------------------------------------------------------------* * Mark Muller Undergraduate at Purdue University * * muller@gn.ecn.purdue.edu Aeronautics & Astronautics Engineering * *-------------------------------------------------------------------------*