Conceived at the height of World War II by English aeronautical engineer Barnes Neville Wallis (1887- 1979), the bouncing bomb was a weapon with a unique purpose; namely the destruction of Hitler's Ruhr Valley-based hydroelectric plants.
Codenamed "Upkeep," the cylinder-shaped bouncing bomb had its origins among naval gunners of two centuries before, who had increased the range of their cannons' projectiles by literally skimming or bouncing them off the water.
The effect had also been noticed by Allied pilots attacking ships. Forced by enemy fire to drop their bombs prematurely, the bombs had, under certain conditions, similarly bounced their way onward to the target. Reasoning that a bomb system able to do this by design would enable the destruction of targets otherwise requiring an impossibly heavy load of explosives, or a suicidal pilot, Wallis set about creating one. Numerous designs of scaled-down "bombs" were tested before Wallis concluded that a casing striking the water at an angle of around seven degrees would produce a reliable bounce. Backspin improved the results greatly.
Successful testing against a disused Welsh dam confirmed that, with a depth-sensitive fuse, and the tamping effect of the water, 6,500 pounds (2,950 kg) of explosive would suffice for each dambusting bomb. But the bombs would need to be dropped from the dangerously low height of 60 feet (18 m), and with a precision previously unheard of in combat warfare. Success was finally achieved with the aid of special sights in each aircraft.
