Nakajima KI 84 Hayate, meaning Gale went by the name of Frank amongst the Allied forces, played a greater role than any other Japanese aircraft during the closing months of the Second World War in the Pacific theatre. It proved itself to be a highly respectable performer quite capable of going toe-to-toe against the proven and improved Mustang P-51, and fielded sufficient firepower and aerial performance to down the well defended, high-flying Boeing B-29 Superfortress heavy bombers. Despite Japan fielding a number of relatively capable fighter platforms towards the closing stages of the Pacific the Ki-84 was the only fighter aircraft to be produced in notable quantities with some 3500 aircraft produced before the end of the Pacific War on 2 September 1945.
Ki-84 pilots were treated to superlative cockpit viewing angles, received proven powerful engines, an aerodynamic slender fuselage, and superior armament a combination of cannons and fully automatic machine guns. This aircraft’s core of success stemmed from its Nakajima Ha-45 Homare 21 direct injection engine, additionally utilised water injection to assist the supercharger in developing 1800-2000 hp from its radial piston power-plant.
At this superior horsepower rating the aircraft reached close to 400 mph and an operational ceiling nearing 35,000 feet with its fuel range gearing up to the far side of 1000 miles. To compare even more favourably the aerodynamic package proved to be highly manoeuvrable in dogfights, coming off favourably against the best the Allied forces had to pit against it. Early flight testing during the summer 1943 at Tachikawa revealed a fair turn of speed when test pilot a Lieutenant Funabashi reached a maximum level flight air speed slightly in excess of 387 mph in the secondary prototype, furthermore in the after war years are late production captured Ki 84 underwent testing in America and recorded a maximum level flight air speed of 422 mph on a mixture of 92 octane AvGas and methanol injection.
It’s lethal firepower, derived from 2 x 12.7 mm calibre fully automatic machine guns nested in the upper part of the front fuselage, with an additional 2 x 20 millimetre calibre automatic cannons mounted inside the leading edges of its wings. Latter variants particularly the bomb and destroyer Ki-84-III which sported hugely impressive firepower in the form of 2 x 20 mm calibre automatic cannons in the nose as well as 2 x wing mounted 30 mm calibre automatic cannons, additionally 551 lb of explosive munitions could be carried in its under-wing bomb racks. Pilots benefited from an 65 mm thick armour-glass cockpit canopy as well as 13 mm armour protecting the seat back and head.
Near the end this highly capable fighter was severely hampered by spares shortages, inconsistent quality of its fuel, poor product quality due to production line interruptions from resource shortages, caused by the concentrated Allied bombing campaign. Later models suffered from landing gear that was prone to buckling, poor upkeep of its high maintenance engine, a severe restriction on the number of available experienced pilots. The centrally mounted 20 mm cannons proved to be difficult to synchronise due to the four bladed propeller design.