Air Force bombs and Navy rockets, as well as Army mortars. Proximity fuzes of a more modern, transistorized design are still used for U.S. The main suppliers were Crosley, RCA, Eastman Kodak, McQuay-Norris and Sylvania. This permitted the purchase of over 22 million fuzes for approximately $1,010 million. As volume increased, efficiency came into play and the cost per fuze fell from $732 in 1942 to $18 in 1945. Procurement contracts increased from $60 million in 1942, to $200 million in 1943, to $300 million in 1944 and were topped by $450 million in 1945. He prevailed and the VT fuzes were first used in the Battle of the Bulge in December 1944, when they made the Allied artillery far more devastating, as all the shells now exploded just before hitting the ground.īy 1944 a large proportion of the American electronics industry concentrated on making the fuzes. Eisenhower protested vehemently and demanded he be allowed to use the fuzes.

The Germans started research in 1930 but never invented a working device. Therefore, they refused to allow the Allied artillery use of the fuzes in 1944. The Pentagon decided it was too dangerous to have a fuze fall into German hands because they might reverse engineer it and create a weapon that would destroy the Allied bombers, or at least find a way to jam the radio signals. (They were ineffective against the much faster V-2 missiles.) There was no risk of a dud falling into enemy hands. Air Force on Japan in 1945, and they were used to defend Britain against the V-1 attacks of 1944, achieving a kill ratio of about 79%. They were incorporated into bombs dropped by the U.S. The fuzes were used in land-based artillery in the South Pacific in 1944. The return signal, reflected from the target, detonates the shell prior to impact and produces the devastating effects.

After the shell is fired and begins rotating, a chemical reaction produces an electrical charge which in turn arms the shell and sends out a radio impulse.

The basic components were a vacuum tube (six inches long and three inches in diameter) a battery, and a radio transmitter and receiver, all of which have to be rugged enough to withstand 20,000 Gs when shot out of a gun at high velocity. Utilization of the Doppler effect of reflected radio waves was the most promising concept, so researchers devised a diode detector arrangement that acted when the amplitude of the reflected signals exceeded a predetermined value. The British had invented the fuze in 1940 but lacked the massive industrial capacity needed to produce it in quantity, so shared the blueprints with civilian researchers at Johns Hopkins University under contract to the U.S.