Very soon after the design of the Ki-43 Hayabusa had been started by Nakajima, the company received instructions from the Imperial Japanese Army to initiate the design of a new interceptor fighter. In this case however, manoeuvrability was required to give precedence to overall speed and rate of climb, and the company's design team selected the 1,250 hp (932 kw) Nakajima Ha-141 as the powerplant for this new project. Of similar configuration to the Ki-43, the new Nakajima Ki-44 prototypes also incorporated the manoeuvring flaps that had been introduced on that aircraft, and carried an armament of two 7.7 mm (0.303 in) and two 12.7 mm (0.50 in) machine guns. First flown on August 1940, the Ki-44 was involved in a series of comparative trials against Kawasaki's Ki-60 prototype, based on the use of the Daimler-Benz DB 601 engine, and an imported Messerschmitt Bf 109E. The result of the evaluation and extensive service trials, showed the Ki-44 to be good enough to enter production, and it was ordered under the designation Army Type 2 Single seat Fighter Model 1A Shoki (demon), company designation Ki-44-Ia, which carried the same armament as the prototypes. A total of only 40 Ki-44-I aircraft was produced, including small numbers of the Ki-44-Ib armed with four 12.7 mm (0.50 in) machine guns, and the similar Ki-44-Ic with some minor refinements.
When introduced into service the high landing speeds and limited manoeuvrability of the Shoki made it unpopular with pilots, and very soon the Ki-44-II with a more powerful Nakajima Ha-109 engine was put into production. Only small numbers of the Ki-44-IIa similarly armed to the Ki-44-Ia, were built, the variant being followed by the major production Ki-44-IIb which apart from the different engine was identical to the Ki-44-Ic. The Ki-44-IIc introduced much heavier armament, comprising of four 20 mm cannon or alternatively two 12.7 mm (0.50 in) machine guns and two 40 mm cannon, and these proved to be very effective when deployed against Allied heavy bombers attacking Japan. However the increased power had done nothing to eliminate the reasons for its unpopularity with the pilots, and in fact, the higher wing loading of this version meant that it had some violent reactions to high speed manoeuvres; however, it later regained their respect because of its capability as an interceptor.
Final production version was the Ki-44-III with a 2,000 hp (1491 kw) Nakajima Ha-145 radial engine, an increase in wing area and enlarged vertical tail surfaces, but comparatively few were built before production ended in late 1944. They included the Ki-44-IIIa and the similar Ki-44-IIIb, armed with four 20 mm cannon, and two 20 mm and two 37 mm cannon respectively.
Nakajima had built a total of 1,225 Ki-44's of all versions, including prototypes, and these were allocated the Allied codename 'Tojo'. They were deployed primarily in Japan, but were used also to protect vital targets, as in Sumatra where they defended the oil fields at Palembang.
I like the Tojo. Typically, it had all HMGs unlike the rival Navy Jack with 20mm cannons. The pilots requested 20mm cannons to intercept US bombers. They were answered with the short-range 40mm Ho-301 instead. Novel, but unworkable vs bombers with heavy defensive fire. You have to brave that fire to ramming distance before opening fire since these had such low velocity and low accuracy. Many Tojos did resort to ramming B-29s. Most pilots stripped these cannons off their Tojos. Why couldn't they have just been given 20mm cannons as they wanted? Even if the 20mm Ho-5 wasn't ready, the Ho-3 was.
ReplyDeleteI could see adapting to the 40mm cannon for dogfights if I had to. The Ki 44 was unbeatable as a vertical tactics fighter. The Ho-301 was unbeatable in low recoil for wing mounting and cycle rate in class. However the 10 r/g of 40mm ammo wound limit bursts to just 2 r/g. This both retains the high fire rate for the caliber, and conserves the pitiful ammo supply. Granted, the pilot would need to get the hang of close-in shooting like a basketball player with pocket mortar rockets, but every hit would score a KO! Of course, the HMGs still had ample ammo supply. The cannon was reserved for the kill shot.
There is reported success of maybe a dozen 37mm cannon armed Tojos knocking down 10 B-29s in a day. The Russians found 25 r/g in their wings when thisAsian base was captured. Who knows? The Ki 44 had stubby re-enforced wings and the 37mm Ho-203 was of moderate recoil power. Or maybe there was a reason it was a success only one day.