In late 1944, with the Allied bombing campaign taking its toll on German infrastructure and war-making capabilities, Luftwaffe High Command enacted the "Emergency Fighter Program" to help stave off defeat. There were numerous contributions to the program though many did not see the "light of day" as it were due to the end of the war or other factors. Two notable projects to emerge from the initiative became the Arado Ar 234 "Blitz" jet-powered bomber and the Heinkel He 162 "Volksjager" - both detailed elsewhere on this site. One entry destined to not see go beyond the drawing boards became the Henschel He P.135 put forth by Henschel Flugzeugwerke AG.
Founded in 1810 and centered on the business of mechanical / automotive engineering for decades, the Henschel concern was making combat aircraft for the German Luftwaffe since the 1930s. When war came to Germany and the rest of Europe in September of 1939, business for many parties boomed but many of Henschel's existing products were of 1930s origin so it attempted several projects during the war with the most successful of these becoming the Hs 129 close-support / anti-tank platform; over 800 were produced before the end. Beyond this, the company had little to hang on its hat on in terms of aviation legacy during the war - the P.87 high-speed bomber, P.75 heavy fighter and P.135 fighter-interceptor were all ultimately-abandoned initiatives.
When the Luftwaffe called for a single-seat jet-powered fighter, Henschel turned to an earlier design it had privately been working on to produce the framework for the proposed "P.135". The aircraft was given a "tailless" design which involved just a single vertical fin and no horizontal planes of any kind at its aft-end. The wing mainplanes of 30.25 foot span were well-swept towards the rear but, of particular note, these were given straight-edged, up-turned tips to break both the leading and trailing sweep lines. The trailing edge was of a saw-tooth style which were very modern for the period. This "compound" swept-wing approach was intended to spread about the forces of high-speed flight when approaching the critical Mach number, reducing vibration and compression along its span and providing for a more stable, safer aircraft capable of extreme-high-speed flight at heavier loads than originally thought.
The 25.5 foot-long fuselage took on a deep appearance with the intake positioned set at the cut-off nose section and the engine exhausting at the rear, just under the tail unit. The cockpit would be seated near midships and feature a raised spine for more internal volume at the expense of vision to the rear. The wings were to be mid-mounted along the sides of the fuselage. A modern tricycle undercarriage would be utilized for ground-running.
Proposed armament was to become 4 x 30mm MK 108 autocannons, two seat under the "chin" of the aircraft and one to each wing root for a formidable punch against Allied bombers of the period. The engine of choice would have been the Heinkel-Hirth HeS 011 turbojet engine, this unit buried within the aft-section of the fighter-interceptor. with its futuristic design and proposed propulsion scheme, the aircraft was estimated to have a maximum speed of 612 miles-per-hour - putting it well out of reach of ground-based fire or counter-interceptors and bomber escorts.
In any event, the P.135 was not selected for further development and only existed as a "paper" airplane for its part in the war - a war which would end with the complete surrender of Germany in May of 1945. Nevertheless, the P.135 deserves its footnote in military aviation history for its rather forward-thinking design.