Variable time fuse revealed as potent U.S.

Variable time fuse revealed as potent U.S. secret weapon FuseseMade In Various Sizes For Use In Navy Guns (See Master Caption). This cross-sectional drawing of a projectile shows how the various portions of the varible time fuse are assembled inside the shell. The heart of the fuse is a vacuum tube which sends out electro-magnetic waves of umpulses at the speed of light, 186,000 miles (297,600 kms.) per second. The impulses are reflected back to the tube by any target that gives a radio reflection, such as metal objects, water or earth. If a variable time fused projectile, in flight, passes within 70 feet (21 meters) of an airplane, reflected inpulses act on the fuse circuit to trigger a switch. The switch causes an electrical detonator to set off the main explosive charge in the projectile.