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Top to bottom: Herrmann annular wing design undertaken at Lockheed. Lockheed 140 Heinkel Wespe ducted-fan VTOL fighter concept developed in 1944 at Vienna. This proposal had been replaced by a more satisfactory design called Lerche by the time hostilities ceased. Bill Rose sile development at Peenemiinde (and even- tually found employment with Lockheed’s Skunk Works). He hoped this idea could be applied to glide bombs as a useful way of increasing range. In 1944, Heinkel engineers used Her- rmann’s research to produce an annular wing ducted-fan VTOL interceptor concept called the Wespe (Wasp). The torpedo-shaped Wespe was a tail-sitter, supported on the ground by three fins with nacelles containing struts and wheels that would be shrouded during flight. A Daimler-Benz DB-109-021 tur- boprop (also referred to as the HeS 021), developed from the Heinkel HeS 011 turbojet, provided power for a six-bladed propeller contained inside the annular wing, with exhaust from the engine exiting at the tail. This compact aircraft had a proposed overall length of approximately 20ft (6.1m), a span of 16ft (4.9m), an anticipated take-off weight of 4,696 Ib (2,130kg) and a maximum speed of 500mph (805km/h) in level flight. The Wespe would be flown with the pilot in a prone posi- tion and was armed with two 30mm MK 108 cannons positioned on either side of the cockpit. This concept never progressed beyond the drawing board and on 25th February 1945 itwas superseded by another design called the Lerche (Lark). Although similar in appearance and carrying the same armament, this larger 30ft (9.14m)-long proposal was powered by two separate Daimler Benz DB605D piston engines driving contra-rotating propellers within the annular wing. The estimated perfor- mance was similar to the Wespe but range, reli- ability and production costs were expected to be significantly better. Initial studies were com- pleted at Vienna on 8th March 1945 as the war in Europe drew to an end. The annular wing ducted-fan concept was also explored in some detail by Dr Alexander Lippisch, who recognised the possibilities offered by this configuration. During his time with the Collins Radio Company in the 1950s, Lippisch supervised the construction of sev- eral ducted-fan models and one full-size mock-up. He filed a series of patents during this period and these designs were usually Lippisch design for high-performance annular wing, ducted fan aircraft. US Patent Office Secret Projects: Flying Saucer Aircraft