The Lippisch-Espenlaub E2 was the first of over 50 swept-wing, tailless designs produced by Lippisch over the next three decades. Though this first effort was less than impressive, it at least was a starting point from which Lippisch began serious, systematic development of tailless designs. In 1924, he was designated Director of the Aeronautical Department of the RhonRossitten-Gesellschaft (RRG, which later became the German Research Institute for Soaring Flight).
With limited resources at his disposal, Lippisch chose an unconventional, step-by-step method of developing his designs, testing the original concept first as a flying model, then as a man-carrying glider, and finally as a powered aircraft. Lippisch considered this approach would produce results in less time and with less expense than a wind tunnel research program . From this design philosophy evolved two famous series of tailless aircraft -- the Storch (stork) and the Delta.
Between 1927 and 1932, eight Storch aircraft were designed by Lippisch, all of them high-wing monoplanes with sweepback. In 1926, a succession of large, free-flying models of various configurations, including canards and the "flying plank" design later adopted by Fauvel in France, led to the Storch I experimental glider, first test-flown in 1927 by Bubi Nehring. Lack of aileron effectiveness was evident in this and the Storch 11 and III that followed. The ailerons were redesigned to approximate the form of the Zanonia seed and Igo Etrich's Taube . Etrich himself recommended the configuration to Lippisch; his faith in the principle was reaffirmed when the 1929 Storch IV glider demonstrated impressive stability and control characteristics with Gunther Gronhoff at the controls. Development work on the Storch series was temporarily interrupted in 1928 when Lippisch collaborated with Fritz von Opel and the rocket manufacturer Sander in performing rocket-powered flights of some Lippisch tailless models. These successful experiments were followed by a manned flight of a rocket-powered tail-first glider, the Ente (duck). Although these experiments also met with moderate success, Lippisch returned to his original interests in 1929. These experiments, and subsequent research on the basic principles of rocket propulsion, provided the foundation for later projects with rocket-propelled aircraft in the late 1930s.
In 1929, the Storch V appeared equipped with a small, 8-hp DKW engine for Lippisch's first attempt at powered flight with the Storch series. Following successful test flights by Gronhoff, a public demonstration of the Storch V was made at Tempelhof Airfield at Berlin in October 1929, with the expectation of obtaining some government financial backing. None came, but the transatlantic pilot Captain Herman Kohl expressed interest in the idea of a tailless aircraft for flights across the Atlantic. With this order in hand, Lippisch stopped work on the Storch VI and began the design of what would eventually become the renowned Delta series. Lippisch later worked on three more versions of the Storch; the Storch VII, powered by a 24-hp engine, won a prize for the first 300 km overland flight of a tailless aircraft when Gronhoff flew the aircraft from the Wasserkuppe to Berlin in 1931 in 1 hour, 55 minutes. The Storch VIII was a privately financed craft that could be flown either with or without tail surfaces attached. The Storch IX training glider appeared in 1933, and was successful enough to prompt two variations, the IX a and b.
Lippisch's methodical, step-by-step experiments had been quite successful with the Storch series, but the Storch was merely a foundation for further efforts to build a pure, all-wing aircraft. From the Storch, with its swept back leading and trailing edges, came the Delta, also a swept back wing but with one essential difference: the trailing edge, from wing tip to wing tip, was a straight line. This triangular wing allowed a thick midsection, with the potential for storing all loads inside the wing.
Following his customary routine, Lippisch proceeded from drawing to flying model to full-scale glider, and finally in June 1931, the powered Delta I was flown on the Wasserkuppe. Again, Gunther Gronhoff's test flights were so successful that another Templehof demonstration was conducted; and again, the Lippisch aircraft was clearly a success, with accounts of Gronhoff's aerobatic skill with the revolutionary airplane appearing in the press in Europe and the United States. Unfortunately, no financial backing materialized.
For the next several years, Lippisch, serving with the RRG (in 1933 reorganized under the title Deutsche Forschungsanstalt fur Segelflug [DFS, German Research Institute for Soaring Flight]), produced dozens of designs for tailless aircraft; some never left the drawing board, and some made it to the model stage. Others, like the Delta, eventually flew and underwent countless modifications as tests revealed deficiencies in stability and control. The Delta series progressed through the Delta IVC, at which point the series designation was changed to DFS 39. The DFS 40, or Delta V, was the last of the series to fly, in 1939.
As the decade came to a close and Germany prepared for war, Lippisch transferred to the Messerschmitt Company in January 1939, where he again became involved in the application of rocket propulsion to tailless aircraft.
After the war ended, Lippisch moved to the United States, where after a few years of government service, he joined Collins Radio Company as an expert on special aeronautical problems. In 1966, he founded Lippisch Research Corporation and developed the X-113A Aerofoil Boat.
Alexander Lippisch died in 1976.