Henschel Hs P.75 Heavy Fighter Aircraft Proposal
The Henschel Hs P.75 heavy fighter and its distinct canard configuration was not furthered beyond the wind tunnel model stage during World War 2.
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The Henschel Hs P.75 appeared in 1941 as a possible contender to the outmoded and outclassed Messerschmitt BF 110 "Zerstorer" heavy fighter for the German Luftwaffe. The heavy fighter had met its match in the Battle of Britain and has become relegated to the night-fighting role as a result. A more capable replacement was needed and Henschel delivered a response with its Hs P.75 idea. The P.75 went about design in a unique way, fitting a pair of engines (and applicable propellers) aft of the cockpit. The layout offered the inherent benefits of an unobstructed forward view and an armament suite that required little in the way of special equipment - the cannons did not have to be synchronized to fire through a spinner propeller blade system and all could be concentrated towards a target area for maximum effect. Conversely, the rear placement of the engine meant that cooling of the twin powerplants would require special consideration. Additionally, there was no safe means for which the pilot to extract himself from the aircraft whilst in flight and at speed for he would have to contend with the set of spinning propeller blades to his rear. This, however, could be countered by having the propeller assemblies jettisoned off before the pilot ejected from his aircraft, requiring some special modifications to the design.
The rear wing, forward canard design was not wholly unique to the Henschel Hs P.75. The Americans attempted the same design concept with their abandoned Curtiss XP-55 "Ascender" as did the Japanese with their Kyushu J7W1 "Shinden". All fitted the main wing assembly to the rear as well as the engine and a propeller set up in a "pusher" configuration with the armament at the front of the fuselage. Despite the promising data collected through wind tunnel trials, the Henschel P.75 was not furthered into a workable prototype form, let alone production-quality examples.
The originally-selected powerplant for the P.75 became a pair of Daimler-Benz DB 610 series in-line piston engines. However, these powerplants were prone to catching fire and suffered from regular overheating prompting the move to the more stable Daimler-Benz DB 603 series engines sometime in 1942. When conjoined as such, the engines were known under the prototype designation of DB 613. They had the potential to deliver a combined 3,500 total horsepower.
The design of the Henschel Hs P.75 was very distinct when compared to contemporary aircraft designs. The main monoplane wing assemblies were fitted low to the extreme rear of the fuselage with a pair of small canard wings situated at the extreme forward. Both wing installations sported sweep along their leading edges though the forward canards also sported sweep along their trailing edges. A vertical tail fin was fitted to the design though this was interestingly mounted as a ventral protrusion as opposed to a traditional dorsal mounting. The fin arrangement helped to protect the propellers from incidental damage during take-off and landing. The bulk of her weight resided to the rear of the design to which the wings, engine and fuel stores were all fitted. The engine arrangement also forced designers to devise a flat, broad fuselage to accommodate the twin systems. The fuselage was a long and slender affair, contoured from its curved nosecone to its curved tail cone propeller spinner. To power the two contra-rotating propellers at the rear, the Daimler-Benz engines drove extension shafts. The aircraft would have operated with a fully-retractable undercarriage system comprised of two main legs and a nose leg, all sporting single wheels. The cockpit was situated in the middle of the fuselage, aft of the armament and ahead of the engine compartment. The cockpit itself featured heavy glazing and views to the rear were limited due to the fuselage spine. Armament was stored in the forward fuselage whilst fuel tanks were secured in each wing and behind the cockpit, ahead of the engine installation. Armament would have been a battery of 4 x 30mm MK 108 cannons seated in pairs, one pair at the extreme forward of the nose and the remaining pair just aft, ahead of the cockpit.
The Henschel Hs P.75 sported a wingspan of 37 feet, 1 inch with a length of 40 feet and a height of 14 feet, 1 inch. Her maximum weight allowance topped 16,535lbs. Performance from her conjoined engine setup would have delivered a service ceiling of 39,370 feet with a maximum top speed in the vicinity of 491 miles per hour.