Tandem engine arrangements were a unique facet of World War 2 fighter design and perhaps best embodied by the German Dornier Do 335 "Pfeil" heavy fighter. Another entry into this category of aircraft arrived in the form of the Lippisch P.13 in November of 1942, designed around a high-speed bomber requirement. The aircraft's design (unrelated to the P.13A and P.13B Lippisch-designed aircraft detailed on this site) was credited to Josef Hubert despite it falling under the Alexander Lippisch name - at the time, Hubert served as the head of Department L of Messerschmitt under Lippisch himself.
The arrangement of the P.13 was largely conventional, seating the single pilot near midships under a tear-drop canopy. Wing mainplanes were set near midships as well and the tail unit was made up of a single rounded vertical fin with a ventral fin added. The undercarriage was wheeled and retractable though of a tail-dragger arrangement. The main legs sat under the wings near the roots and the tail wheel was fitted, as expected, under the tail's mass.
There were two unique qualities of the design: firstly was the engine pairing which seated one Daimler-Benz DB605B inline piston unit at the nose and a second DB605B at the rear, its placement ahead of the vertical tailplane while the spinner extended beyond the plane (driven by way of a shaft). One engine was set to "pull" the aircraft and the other to "push" it - the combined power making for an exceptionally fast and powerful aeroplane (as proven by the Do 335 which flew late in the war). Each engine developed 1,475 horsepower and drove three-bladed propeller units and, internally, there were five total fuel tanks to feed both engines.
The second unique quality of the aircraft was its wing mainplanes which featured varying degrees of sweepback for low- and high-speed flying. The appendages had two levels of sweep: nearer the wing roots it was 18 degrees and outboard of this it was increased to 38 degrees. There was enough useful area within the mainplanes that no horizontal tail surfaces were used - as such the P.13 was considered a "tailless" aircraft design.
The P.13 was to rely on its inherent speed to advance beyond any enemy air defenses including ground-based guns and airborne interceptors. As such, no defensive armament was fitted to the design. Its sole proposed armament provision was an underfuselage (centerline) hardpoint for a single conventional drop bomb.
Work on the P.13 abruptly ended when Department L was closed by Messerschmitt in April of 1943 and this ended design work on several forward-thinking projects including the P.13. Alexander Lippisch then relocated to Vienna to work at the Aeronautic Research Institute of Vienna and produced a whole slew of new ideas, some of which impacted Cold War-era aircraft design, mainly for the Americans.
The P.13, as designed, was proposed with a wingspan of 42 feet, a length of 30.9 feet and a height of 16.8 feet. No performance specifications were given.