Measures for Progress: A History of the National Bureau of Standards

392 WORLD WAR II RESEARCH (1941-45)
The miniaturization of the elec-
tron tube for use in the radio
proximity fuze.
this stage in the basic design of the fuze, the Army set up a specific require-
ment. They wanted a VT fuze for their new 4.5-inch airborne rocket, then
on the drawing boards, for use against the German Luftwaffe.
With fuze dimensions agreed upon, its design was completed in 2 days
and construction of test models began. Complicated mechanical and plastic
parts were fabricated by hand. Temporary switch and safety mechanisms
had to be used. The batteries available were still too large for a service fuze
but National Carbon and Burgess Battery were working on smaller ones.79
The final design of the fuze head consisted essentially of a radio transmitter
and receiver, a selective amplifier, an electronic switch, a detonator, an elec-
tric power supply, and arming and safety devices.80 Since the 4.5-inch rocket
was not ready, the fuze was set in a 3l/4-inch substitute rocket. Test opera-
tions off the coast near Wilmington, N.C., started a month after receiving the
requirement.
George W. Vinal's electrochemistry section in July 1941 produced a satisfactory low-
temperature wet (perchloric acid) battery for use in the fuze, measuring 2% x 21/2 inches,
later replaced by a commercial dry battery (New Weapons for Air Warfare, p. 184).
C. H. Page and A. V. Astin, "Survey of proximity fuze development," Am. J. Phys. 15,
95,98 (1947).
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