Nakajima Ki-84 Hayate
The Ki-84 Hayate ("Gale"), Allied reporting name "Frank", was a single-seat fighter built by the Nakajima Aircraft Company for the Imperial Japanese Army Air Service in the last two years of the Second World War. Fast, heavily armed and, unusually for a Japanese design, fitted with armour and self-sealing fuel tanks, it is generally regarded as Japan's best fighter to serve in large numbers; 3,514 were built. A single example survives, on display at the Chiran Peace Museum in Kagoshima, Japan.
Why It Mattered
The Ki-84 Hayate — the name means "Gale" — was the Imperial Japanese Army Air Service's last and best wartime fighter, known to its opponents by the Allied reporting name "Frank" and to the Army as the Type 4 Fighter. It is generally considered Japan's finest fighter to have operated in large numbers. Postwar American testing found its performance equal to that of many contemporary American piston-engined fighters. Yet it reached service only in 1944, when good fuel, materials and experienced pilots were already scarce in Japan, and a single example survives today.
Design Notes
The Ki-84 began in early 1942, when the Army instructed Nakajima to develop an all-purpose, long-range fighter able to match the best Western fighters then in use. The design team, headed by T. Koyama, set out to fix the known weaknesses of the earlier Ki-43: insufficient firepower, poor defensive armour and a lack of climbing speed. Breaking with Japanese practice, the Ki-84 carried pilot armour and self-sealing fuel tanks. Its Nakajima Homare engine, an 18-cylinder radial rated at up to 2,000 hp, drove a four-blade propeller. Armament was heavy by Japanese standards: two 12.7 mm machine guns in the nose and two 20 mm cannon in the wings. The design's weakness was upkeep: the Homare was high-maintenance, and landing-gear legs made from late-war steel of poor quality were prone to collapse.
Operational History
The prototype made its maiden flight in April 1943, and deliveries began only a month later. The Ki-84 entered Army service in March 1944, and its first unit was sent to China, where it saw action against the USAAF's Fourteenth Air Force. Its first major operation was the Battle of Leyte in late 1944, where limited numbers and serviceability problems blunted its impact. Ki-84s afterwards fought over China, Burma, the Philippines and the Japanese home islands, facing Allied fighters and intercepting high-flying B-29 Superfortress bombers. Bomber-destroyer and high-altitude interceptor variants were also built. Production at Nakajima's Ota and Utsunomiya plants reached 3,514 aircraft before the war ended. After the war, captured Ki-84s flew on in China, where the People's Liberation Army Air Force operated them into the 1950s, and briefly with Indonesian forces during their struggle against the Dutch.
Afterlife
One Ki-84 survives: serial number 1446, captured at Clark Field in the Philippines in 1945. Shipped to the United States aboard the escort carrier USS Long Island, it was stored at Park Ridge, Illinois, and in 1952 was sold as surplus to Edward Maloney. The museum had it restored to flying condition, and on 25 June 1963 it flew again, registered N3385G — by then the last Japanese aircraft of the war still airworthy — and appeared at American airshows through the 1960s. In 1973 it returned to Japan and flew at the Japan International Aerospace Show, the first time a Japanese wartime fighter had flown in Japanese skies since 1945. After display at the Arashiyama Museum near Kyoto and four years in storage following that museum's closure, the aircraft became a centerpiece of the Chiran Peace Museum for Kamikaze Pilots in Kagoshima Prefecture, where it remains on display as the world's only Ki-84.