Enzian

The Enzian (named for a genus of mountain flower, in English the Gentian) was a German WWII surface-to-air anti-aircraft missile that was the first to use a radio controlled guidance system. During the missile's development in the late stages of the war, it was plagued by organisational problems and was cancelled before becoming operational.

As early as 1943 it was becoming clear Messerschmitt's Me 163 interceptor would be difficult to use in combat. After flying to the 25,000–30,000 ft (7,600–9,100 m) altitude of the bombers, it had only a few minutes to track them down before running out of fuel. Even if it did manage to find the bombers, it had the equally prickly problem of lacking a weapon that could be aimed effectively while closing on the target at some 400 mph (640 km/h; 350 kn).

Dr Wurster of Messerschmitt suggested the answer in the form of Flak Rakete 1 (FR-1) in 1943. Instead of tracking down the planes, the rocket would fly just in front of the target and then detonate a 500 kg (1,100 lb) warhead, in hope of bringing down several bombers at once. With no human pilot on board, and thus no need to limit takeoff acceleration, the rocket could use solid fuel boosters (four Schmidding 109-553s, for a total of 7,000 kg (15,000 lb) thrust, grouped around the exterior), reducing the amount of fuel needed for the rest of the climb by the sustainer motor, a Walther RI-10B. The liquid fueled sustainer used a combination of SV-Stoff and Br-Stoff (petrol), catalyzed by an amount of T-Stoff. The result, even with the heavy warhead, was that a much smaller airframe was needed to carry the required fuel - so small it could be portable and launched from a modified 88 mm gun mounting.

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