The Lippisch P.12, P.13a and P.13b were related design projects for a ramjet-powered delta wing interceptor aircraft studied in 1944 by German designer Alexander Lippisch. The P.12 and P.13a were unarmed, relying on reinforced wings to ram its opponent. The P.13a and b were to be powered by powdered coal. The DM-1 was a full-size glider, flown to test the P.12/13a low-speed aerodynamics. The design series were unrelated to the earlier P.13 produced by Messerschmitt's Lippisch design office. Design and development Initial studies During 1942, while still working on the Messerschmitt Me 163 rocket fighter, Alexander Lippisch developed a sharply-swept, leaf-shaped delta wing which he believed was capable of supersonic flight. Out of this and subsequent development of the P.11/Delta VI "power wing" through 1943 and early 1944, he conceived the idea of a hollow delta wing with its interior shaped like a ramjet duct. As an interceptor fighter it would achieve supersonic speeds but would carry no armament. Instead it would be heavily reinforced and would ram its opponent. Initially conceived as a disposable machine with the pilot bailing out at the end of the mission, a landing skid was later added. Launch to ramjet operational speed would be via catapult and/or booster rockets. The resulting design was initially assumed to use conventional liquid fuel and designated the P.12. But Lippisch had also become convinced of the benefits of solid fuel for short-duration high-speed flight and adopted this power source as the P.13. The design of both types then proceeded in parallel. P.12 The P.12 was never fully defined but comprised studies of many variations. A model of it showed a typical configuration comprising a highly-swept delta flying wing with a protruding nose intake, raised cockpit canopy and single tail fin. Small turned-down winglets or "ears" were located at the wing tips. The wing centre section was hollow, with air ducts on either side of the cockpit leading to a large cavity which comprised the ramjet. The engine exhausted through a wide nozzle with control flaps above and below. Later iterations included a thick tail fin almost as large as one wing and with its forward section comprising the pilot's cockpit, now fully raised above the wing, and/or a tubular central ramjet. P.13a The solid-fuel powered P.13 was one of several distinct Lippisch design studies to be so designated and became identified as the P/13a. It underwent much the