Radio age research, manufacturing, communications, broadcasting, television (1941)

MISSILES WITH "RADIO BRAINS" " V-T" Fuse. One of War's Best Kept Secrets was Called "Madame X' by RCA Workers Who Made Over Five Million of Them. A MODERN miracle — conceived in the minds and machines of America—took place in the air over Britain in the summer of 1944. For many months, the British Isles had undergone a terrifying ordeal of buzz bombs. Damage was mounting; casualties were great and increasing almost daily. Sud- denly in June of that year, observ- ers noted a sharp increase in the number of V-ls shot down by ground fire. In that month, only one out of every five bombs launched from France reached English cities and countryside. Germany's "secret weapon" had met its match. Un- known to more than a few high military officers and a handful of scientists it was the "proximity fuse," developed in American lab- oratories and built in American fac- tories which had accomplished the feat. The fuse, next to the atomic bomb was the best kept secret of the war. Thousands of RCA employees worked on the fuse in two of the Company's plants at Camden, New Jersey, and Bloomington, Indiana. Although they assembled more than 18,000 of these lethal weapons a day at the height of production, they knew only that the project was called "Madame X." According to Navy officials, ten million of the fuses were produced nationally from October, 1942 to V-J Day. Of this amount, RCA Vic- tor supplied the armed forces with five and a half million, or more than half the entire output, making the company the largest producer of the apparatus in the country. Known officially to the Navy as the "VT Fuse," "Madame X" is a complete four-tube radio receiver and transmitter employing radar principles. No larger than a pint milk bottle, it is enclosed within the case of a five-inch shell. When such a projectile is fired, the fuse emits radio waves. As the radio waves bounce against the target, they are reflected back and are picked up by the receiver in the fuse. As the shell approaches closer to its objec- tive, the returning signal grows stronger until it reaches sufficient strength to operate the detonating mechanism. Safety devices keep the shells from being discharged pre- maturely. Miniature Tubes Used Design of the miniature glass tubes was a feat in itself. Tiny as the tubes used in popular hearing aids, those designed for the prox- imity fuse had to be sturdy enough to withstand the terrific impact of the propelling discharge of the gun and the centrifugal force caused by the whirling of the shell at high speed as it left the gun muzzle. American tube designers attacked these formidable problems and solved them. To supply the tubes and associ- ated mechanisms with power, engi- neers developed a battery which was inert until the shell started its travel through the air. At that in- stant, the chemicals began to react and generate the required current. Work Began Before Pearl Harbor Work on "Madame X" started a month before Pearl Harbor when Radio Corporation of America scientists and RCA Victor engi- neers were called into conference. Ten months later, working in co- operation with representatives of the Navy's Bureau of Ordnance and the Office of Scientific Research and Development, they put the first fuse into production at Bloomington. As an example of the ruggedness of the fuse, it had to withstand a sudden jump in velocity from zero to 2,000 miles an hour in a space of ten feet, as the projectile was fired from the gun. At the same time, it was spinning at the projectile's rate of 25,000 revolutions a minute. The utmost care was necessary in the manufacture of the delicate de- vice. In areas where the fuse was assembled the air was conditioned to keep out excessive moisture and foreign elements. When the fuse was fully assembled, molten wax was poured over the entire unit to keep it firm inside its housing. "E" Flag for Achievement So secret was the activity that the Navy Department delayed granting an "E" flag for accom- plishment to the Bloomington fac- tory. They did not want attention attracted to the plant. With the lifting of some restrictions on the proximity fuse, however, it was learned that the Navy Department was recognizing the Bloomington plant's tremendous contribution by awarding it the Navy Ordnance Flag with three stars. The Camden plant, which already has an Army- Navy E Flag with four stars for other outstanding accomplishments, is also to be awarded a Navy Ord- nance Flag with one star for its fuse production record. THE "VT fuse" (left) IS SHOWN AT RIGHT AS IT APPEARS WHEN INSERTED IN NOSE OF 5-INCH SHELL. U. S. .Vnr?/ Pho'o [8 RADIO AGE]