Manshu Ki.65 and Ki.98
In February 1940 the IJA Aero-Technical Research Institute (
Rikugun) requested several Japanese aircraft manufacturers to develop a high-performance interceptor to replace the Ki.44.
Kawasaki received orders to develop the Ki.60 and the Ki.61 fighters powered by one 1,100 hp Ha-40 inline, liquid cooled engine. Nakajima developed the Ki.62 powered by one Ha-40 and the Ki.64 powered by one 1,050 hp Ha-102 radial, air-cooled engine. Mitsubishi proposed to modify the J2M
Raiden to suit the needs of the IJA.
The new aircraft, named Ki.65, should be powered by a 1,080 hp Ha-102
Zuisei or a 1,850 hp Ha-101
Kasei radial engines. Mitsubishi hoped to have its first prototype completed in March 1942, but the firm was so overworked getting ready for the war that the IA decided to transfer the project to Manshu Hikoki Seizo K.K. in the spring of 1941.
The
Koku Hombu suggested using a 1,850 hp Ha-111 engine for the prototype and a 2,200 Ha-43/Ha-211 18-cylinder double-star radial engine for the production version. The diameter of the Ha-211 was 11 cm shorter than that of the Ha-101 used by the
Raiden, allowing Manshu designers to use a reduced front section fuselage, shortening the shaft extension. Increased engine power allowed a new wing with increased span and surface to improve high-altitude manoeuvrability.
Late in 1942 the
Koku Hombu issued a heavy fighter specification, calling for one high-altitude interceptor that could be modified for use in ground close-support and anti-landing ships duties. The armour required for this type of attacks and the weight of the armament required the use of very powerful engines, so most of the projects presented (Kawasaki Ki.102, Mitsubishi Ki.83 and Rikugun Ki.93) were twin engine airplanes.
The firm Manshu Hikoki Seizo K.K. decided to adopt the aerodynamic solutions of the Focke-Wulf with BMW 803A for its single engine project Ki.98, which could meet the specification with half the power of the Ki.83. By1941, the German firm BMW had developed a 4,500 hp, 28 cylinder, 4-row radial, liquid-cooled monster engine called BMW 803.
Following the cancellation of the Focke-Wulf 238 bomber project, Kurt Tank's team designed a 9,000 kg high-altitude interceptor powered by one BMW 803A with two-stage, four-speed supercharger. The twin boom configuration allowed the installation of a heavy engine in the centre of gravity of the aircraft, which improved manoeuvrability and allowed to build smaller airframes, with material and weight savings. The forward section of the fuselage allowed the installation of heavy non-synchronized cannons with dual use, anti-tank and anti-bomber.
The main drawback of this configuration was the cooling of the engine; therefore, it was necessary to design a new tricycle landing gear and a bail-out system for the pilot. In July 1943, the IJA authorized the construction of a prototype, powered by one 2,200 hp Ha-211-III air-cooled radial engine and armed with one 37 mm Ho-204 and two 20 mm Ho-5 cannons. In the spring of 1944, the
Koku Hombu was informed of the operational characteristics of the new Ru-303 turbo-supercharger, which Mitsubishi would begin producing in 1945.
The IJA decided to prioritize the construction of the high-altitude version of the 1942 specification and instructed Manshu that the Ki.98 should be for modified B-29s interception duties, powered by one Ha-211 Ru turbocharged engine. Manshu expected to have the prototype finished by mid1945, but when the Red Army began the invasion of Manchuria in August, the plane was destroyed, along with all project documentation to avoid capture by the Soviets.
Mitsubishi Ki.65 technical data
Wingspan: 10.8 m, length: 9.5 m, height: 3.81 m, wing area: 20 sq.m, max speed: 620 kph, max weight: 2,720 kg, ceiling: 10,000 m, endurance: 7.5 hr with drop tank, engine: one 1,530 hp Mitsubishi Ha-101
Kasei radial, armament: 2 x 20 mm Ho-5 cannons in the wings and two 7.7 mm Type 97 light machine guns in the nose.
Manshu Ki.65 technical data
Wingspan: 12.5 m, length: 9.7 m, height: 2.97 m, wing area: 24 sq.m, max speed: 680 kph, max weight: 4,160 kg, engine: one 2,200 hp Mitsubishi Ha-211 radial, armament: 2 x 20 mm Ho-5 cannons in the wings and two 12.7 mm Ho-103 heavy machine guns in the nose.
Manshu Ki.98 technical data
Wingspan: 11.26 m, length: 11.40 m, height: 4.30 m, wing area: 24 sq.m, max speed: 731 kph, max weight: 4,500 kg, ceiling: 10,000 m, range: 1,250 km.