High Quality Content by WIKIPEDIA articles! Wasserfall was essentially an anti-aircraft development of the V2 rocket, sharing the same general layout and shaping. Since the missile had to fly only to the altitudes of the attacking bombers, and needed a far smaller warhead to destroy these, it could be much smaller than the V2, about 1/4 the size. The Wasserfall design also included an additional set of fins located at the middle of the fuselage to provide extra maneuvering capability. Unlike the V2, Wasserfall was designed to stand ready for periods of up to a month and fire on command, therefore the volatile liquid oxygen used in the V2 was inappropriate. A new engine design, developed by Dr. Walter Thiel, was based on Visol (vinyl isobutyl ether) and SV-Stoff, or Salpeter, (90% nitric acid, 10% sulfuric acid).