Free Secret Weapons by Brian Ford Page A

American soil would cause the United States to devote her priorities to defending herself, rather than protecting Britain. In this way, the Germans would have less resistance from the British forces and the occupation of the United Kingdom would be easier to attain. However, these detailed plans failed to bear fruit.
    Flying triangles
    The DM-series of delta-winged planes was a joint project of the Darmstadt and Munich Akafliegs ( Akademische Fliegergruppen , academic flight research teams). During planning all limits were set aside and what may seem impossible today was seriously considered, such as the DM-4 with a planned wing area of 753ft 2 (70m 2 ) that was calculated to reach speeds of 1,000mph (1,600km/h), well above the speed of sound.
    These aircraft were not the only delta-shaped planes envisaged in Germany during the war. Alexander Lippisch, the distinguished Munich-born engineer, proposed to develop a ramjet defence fighter powered by a new and highly efficient form of propulsion unit. Rather than relying on air compressed by a spinning turbine, this new design – the ramjet – used the plane’s forward motion to collect and compress the air. Ramjets could operate at very high efficiency, but – because the plane must already be moving to compress the incoming air – they could not be used to propel the plane from a standing start. The ramjet only took over when the plane was already moving at speed. Lippisch named his design Projekt P-13a .
    He persuaded the Darmstadt Akaflieg to build a full-scale flying prototype, which the company designated the Darmstadt D-33. Work was proceeding when the Akaflieg Darmstadt workshop was hit during an Allied bombing raid in September 1944, so the D-33 project was transferred to the Munich Akaflieg where the work was completed. They renamed the D-33 the Akaflieg Darmstadt/Akaflieg München DM-1. It was designed as a single-seat glider made from steel tubing and plywood that was impregnated with Bakelite, at the time a highly innovative process. The glider was discovered by United States soldiers when they arrived on site in May 1945, and the prototype was then inspected by Charles Lindbergh who arranged for it to be shipped back to the United States. The prototype was wind-tunnel tested and examined by scientists from the National Advisory Committee for Aeronautics (which later gave rise to today’s NASA – National Air and Space Administration). Among the planes inspired by this German design, as by the Hortens’ flying wing, were the Convair XP-92, America’s first delta-wing fighter, and Convair’s F-102 Delta Dagger which flew in Vietnam. Of a similar, uncompromising delta design was the Convair F-2Y Sea Dart which was a seaplane fighter that took off on buoyant skis from the surface of a body of water.
    In Britain, research into the delta-wing concept gave rise to the Handley Page HP-115 and the Fairey Delta 2 or FD2 – the first plane to fly faster than 1,000mph (1,609km/h) – and then the great Avro Vulcan bomber. These are the planes that gave much of the technical data needed in the development of Concorde, the successful supersonic passenger aircraft. Once, when flying aboard Concorde to New York, I was told by a captain that it was not useful to think of Concorde as a supersonic airliner. That didn’t make sense to him – his advice was to envisage it instead as a huge supersonic jet fighter that carried passengers instead of weapons. He was right: that made far more sense.
Two aircraft in one
    One novel method of reaching the United States from Germany was the proposal for a hybrid of two planes. A Heinkel He-177 would be used to transport a Dornier Do-217 bomber equipped with an extra Lorin-Staustrahltriebwerk ramjet engine until the planes were sufficiently close to the United States for the Do-217 to be released and fly on towards the target. The plane would deliver its bomb to United States territory and then be ditched in the Western Atlantic,