If you had one of these, what would you do with it? It is, in fact, the brainchild of an Austrian scientist with the improbable name of Zippermeyer, who was responsible for wasting a good deal of Hitler's money on what one Allied intelligence report generously refers to as "crackpot notions." This particular boondoggle was called the "Whirlwind Cannon" or Windkanone, which, according to Jack Sergeant of Fortean Times:
was meant to produce artificial ‘whirlwinds’ by generating explosions in a combustion chamber and directing them through specially designed nozzles at the target. Experiments with a small cannon supposedly shattered planks at 200-yard (183m) range, and a full-size one was built. Fortunately for British and American aircraft, the effect was impossible to reproduce at high altitudes and the project was scrapped. The huge hulk of the ‘Whirlwind Cannon’ itself, though, was discovered rusting and abandoned by bemused Allied forces on the Artillery Proving ground at Hillersleben in April 1945.
The Windkanone was not Zippermeyer's only infernal device. There was also the "Luftkanone or ‘Sound Cannon’"
which burned methane and air to produce a rapid series of explosions that were beamed by ‘sound-mirrors’ into the sky; the resulting noise built up into a high-pitched tone which, apparantly, had been shown as lethal to animals at close range and uncomfortable for human beings at 300 yards (274m). Ultimately, though, the ‘Sound Cannon’ was doomed by the same limitations that had beset the ‘Whirlwind Cannon’ – the impossibility of getting the destructive effects high enough to actually attack a flying target.
On the whole, Sergeant concludes, the Zippermeyer implements of destruction were, like other sonic weapons addressed in his article, "large, cumbersome, close-range devices resulting in ruptured eardrums."