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From: Elunderik@Netscape.Net Date: 10:00 PM 2/27/06 Subject: The "Cuzaux-effect" And The 1930's Bomber-paradigm > This is far short of a definitive comment on the "Cuzaux Effect,' which >most certainly did not refute the bomber orthodoxy, since it is a myth (I >think). According to a letter to _Flight_ (bibliographic reference pends a >good long trawl through my crawlspace storage) by John North in refutation, >was so dubbed for its alleged discovery at a French Armee de l'Air proving >ground at some point. The physical supposition behind the effect is that >due to conservation of angular momentum, spinning objects react in non->intuitive ways to outside forces that tend to move their axis of rotation. >Hence, tops and allegedly bullets moving through a slipstream at an angle >to their trajectory will behave in ways described by the gyroscope >equations, which apparently do not include any measurable loss of accuracy >in this case, although I did not persist long enough in mechanics courses >to have any hope of comprehending the problem. That said, John North was There's nothing mythical or alleged about this effect. A similar effect occurs in spinning projectiles fired on land. Briefly, the spinning projectile resists changes in direction, but aerodynamic forces cause it to do so anyway, which is why properly stabilized projectiles land point-first. As the projectile "noses over", the resultant Magnus force acts in a direction at right angles to the projectile's axis, Projectiles fired from a gun with right-hand-twist rifling will tend to drift to the right. Likely the best-known example of this is the WW1 German Lange Pistole 08, better known as the "Artillery Luger", which had sight settings out to a rather optimistic 800m. As the sight leaf is elevated, it can be seen to move horizontally, moving the point of aim to account for the lateral drift caused by the Magnus force. In the case of the aircraft guns being discussed here, the airflow over the bullet causes a similar yawing effect, so that not only is the projectile deflected laterally by the airstream, it also has a vertical drift. The vertical drift is in opposite directions on opposite sides of the aircraft. It may well be that the effect has minimal impact on aerial gunnery given the high velocities and short ranges involved. Perhaps the French were considering overly optimistic engagement ranges for bomber defensive armament. And to answer Mr. Scheben's query, this phenomenon does not affect a fighter's guns because they are firing along the axis of flight, and thus the projectiles aren't exposed to the sort of lateral airflow that those fired from a bomber's guns see. FWIW, Ed Rudnicki "Rudnicki, Edward J [Amsrd-Aar-Aex]" <Ed.Rudnicki@Us.Army.Mil> ----- For subscription help, go to: http://www.h-net.org/lists/help/ To change your subscription settings, go to http://h-net.msu.edu/cgi-bin/wa?SUBED1=h-war -----
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