 Flaming onion

The flaming onion was a 37 mm Hotchkiss revolving-barrel anti-aircraft gun used by the German army at the beginning of World War I, the name referring to both the gun, and especially the flare or tracer ammunition it fired.The American "balloon-buster" ace, Frank Luke, was a prominent victim of later versions of this device, and it was mentioned in Eddie Rickenbacker's book "Fighting the Flying Circus" and in many "Biggles" stories.