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> At 17:11 2/28/2006, H-War List Editor David Silbey wrote: 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,' ... so dubbed for its alleged discovery at a French Armee de l'Air proving ground at some point. Nice that someone seems to recognize the term, as I certainly do not and cannot help in this regard. Regardless of the specific origin of the term, the whole account which Mr. Lindgjerdet paraphrases in his query seems rather seriously confused. I will attempt only the very barest sketch of the ballistics involved. For more it is very desirable to use diagrams. One treatment that is available on line is contained in a U.S. Department of Defense handbook on fire control systems which may be found at http://combatindex.com/mil_docs/pdf/Hopper/MIL-HDBK/CI-799-MH-3983-2901.pdf Very briefly, however, we can understand the basics most easily by starting with a simplified case in which any wind relative to the gun is exactly aligned with the gun's bore and there are no crosswind components. At the instant of firing then the axis of the projectile will be exactly aligned with the relative wind, which is to say that its angle of attack (AOA) is zero. As the projectile is accelerated by gravity, however, gyroscopic precessional moments cause the axis to deviate from the relative wind, so that AOA differs from zero. This nonzero AOA induces a lift force, as well as a lift-induced turning moment which in turn causes added precession. The net result is what is called drift. Now consider the case in which there is some component of relative wind across the line of fire -- whether because the gun is firing off to the side of a moving aircraft or ship, or simply because there is a crosswind. This introduces further complications, of which the greatest is what is called "jump." In this case there is a nonzero AOA at the instant of firing. For instance if a gun which has an initial velocity of 1000 m/s is fired directly abeam from an aircraft flying at 100 m/s (360 km/h) then the AOA is approximately 0.1 rad or 5.7 deg. This will of course produce a disturbance to the trajectory, principally in the horizontal plane. Perhaps this is what the so-called "Cuzaux-effect" was about -- although it was in fact already well known as jump. U.S. WW II airborne turret fire control systems accounted for all the ballistic and relative-motion effects to an adequate level of accuracy. There was nothing new in the mathematics, only in the magnitude of some of the quantities involved. A full treatment may be found in Kaj L. Nielsen and James F. Heyda, _The Mathematical Theory of Airborne Fire Control,_ NAVORD Report 1493 (Washington: Bureau of Ordnance, U. S. Navy, 20 Jul 1951) >From: Frode Lindgjerdet <Fr-Lind@Online.No> Date: 2/26/06 Subject: The "Cuzaux-effect" And The 1930's Bomber-paradigm > >....This was supposed to be one of the major blows to the so-called bomber-paradigm, formulated among others by British politician Stanley Baldwin in his words the bomber will always get through (1932). According to this, the speed, climbing rate and operational ceiling of bomber relative to fighter preformance were developing in favor of the former. Combined with heavy defensive weaponry, the bomber would be virtually invulnerable to fighter attack. During the early 1930s the aeronautical revolution initially favored larger multi-engined aircraft. [Ronald Miller and David Sawers, _The Technical Development of Modern Aviation_ (New York: Praeger Publishers, 1970)] It was supposed by many (including some who ought to have been able to see the fallacy) that this was inherent and that fighters could never match bombers in performance. It was known from Great War experience that bomber defensive armament was unlikely to shoot down very many fighters, but the supposed performance advantages of bombers led to optimism that bomber losses could be held to fairly low levels regardless. (Since Norway had no Great War experience, however, perhaps it was not realized that defensive armament could not be expected to achieve very much regardless of the supposed "Cuzaux-effect.") The other source of the confidence in the bomber was over-optimism about target-system vulnerability. It was imagined that an enemy's key industries could be shattered with just a few bombing raids. Because of this, bomber sortie loss rates of the order of 10% seemed tolerable. When realism finally set it, it became apparent that anything much in excess of 1% sortie loss rate would mean certain failure of a bombing campaign. >In the Spanish civil war, it was discovered that even slower but more maneuverable biplanes were able to down faster bombers, and even fighters. This seems rather addled. I had a friend who destroyed a Soviet MiG-15 fighter while flying a naval patrol bomber once. Such things could happen, but it was not to be counted upon. Much the same thing could be said of lightly-armed, slow biplanes killing modern bombers and fighters. Will O'Neill "William D. O'neil" <W.D.Oneil@Pobox.Com> ----- 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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