Dornier Do 335 Pfeil a

In 1937, Dornier obtained a patent for a plane with two engines in the fuselage, driving the pull and push propellers. The design was marked P.59, and its concepts were refined in 1939 in the P.59-05 variant, after which the design was put in a drawer. This type of plane was not needed at the time. Nevertheless, limited experimental work was carried out, the result of which was a small Goppingen Go-9 plane, with an aerodynamic system obtained from P.59, as well as three-support landing gear with a front wheel and an engine driving a push propeller through a long shaft. The results of these experiments were used when designing the P.231 aircraft in several variants - also combining piston and jet propulsion. When in 1942 the RLM announced the requirements for a high-speed multipurpose aircraft, the equivalent of the British Mosquito, Dornier proposed the P.231 as a rather unusual answer. Despite the risks posed by the different P.231 concept, Dornier was commissioned to build several prototypes.