The Ki-27 was the Imperial Japanese Army Air Force's main fighter until the start of World War II. When placed into combat service over northern China in March 1938, the Ki-27 enjoyed air superiority until the introduction of the faster Soviet-built Polikarpov I-16 fighters by the Chinese.
Nakajima Ki-27 oli Japanin Keisarillisen armeijan ilmavoimien käyttämä hävittäjälentokone. Se oli armeijan vastine laivaston käyttämälle A5M "Claude" -konetyypille.
Version B sama moottori tuotti tehoa 780 hv (582 kW).
Konetyypillä oli kaksikin eri kutsumanimeä: Liittoutuneiden antama "Nate" sekä keskisemmän Manner-Aasian sotanäyttämöillä (Kiina, Burma sekä Intia) käytetty "Abdul". Se taisteli muiden tyyppien ohella Polikarpov I-16:ta vastaan Kiinan alueilla.
Nakajima Ki-27 oli aseistettu kahdella 7,7 mm kevyellä konekiväärillä, ja se pystyi kuljettamaan 100 kg pommikuormaa ulkoisesti. Myöhempiin versioihin vaihdettiin toiseksi konekivääriksi 12,7 mm konekivääri.
Konetyyppiä tuotettiin arviolta lähes 3 500 kappaletta, Nakajima ei ollut sen ainoa valmistaja. Valmistus päättyi sodan loppumisen myötä. Ki-27:ää käytettiin harjoituskoneena sodan myöhemmissä vaiheissa, kamikaze-käytön ohella.
In the 1939 Battle of Khalkhin Gol against the USSR in Mongolia, the Ki-27 faced both Polikarpov I-15 biplane and Polikarpov I-16 monoplane fighters. In the initial phase of the conflict, its performance was a match for the early model I-16s, and was considerably superior to the I-15 biplane. With better trained Ki-27 pilots, the IJAAF gained aerial superiority. The Ki-27 was armed with two 7.7 mm (.303 in) Type 89 machine guns and as with most aircraft of the period, lacked armor protection for the pilot and self-sealing or fire suppression in the fuel tanks.
Later, the Soviet Air Force received improved I-16s. The faster, more heavily armed (with twin wing-mounted 20mm ShVAK cannons) and armored I-16 now nullified the Ki-27's advantages and it could now escape from the Ki-27 in a dive. The VVS introduced new tactics consisting of flying in large tightly knit formations, attacking with altitude and/or speed advantage and hit-and-run (high-energy) tactics much as Claire Chennault would later formulate for the 1941-era Flying Tigers (likewise to fly against Japanese forces).
Crew: one, pilot
Length: 7.53 m (24 ft 8 in)
Wingspan: 11.31 m (37 ft 1¼ in)
Height: 3.28 m (10 ft 8 in)
Wing area: 18.56 m² (199.777 ft²)
Empty weight: 1,110 kg (2,588 lb)
Loaded weight: 1,547 kg (3,523 lb)
Max. takeoff weight: 1,790 kg (3,946 lb)
Powerplant: 1 × Nakajima Ha-1 Otsu air-cooled radial engine, 485 kW / 650 hp
Maximum speed: 470 km/h (292 mph)
Cruise speed: 350 km/h (218 mph)
Range: 627 km (390 mi)
Ferry range: 1100 km (682 mi)
Service ceiling: 12,250 m (32,940 ft)
Rate of climb: 15.3 m/s (3,010 ft/min)
Wing loading: 83.35 kg/m² (18 lb/ft²)
Power/mass: 0.30 kW/kg (0.18 hp/lb)
Armament: 2 × 7.7 mm Type 89 machine guns, 500 rounds/gun
or 1 x 12.7 mm Ho-103 machine gun and 1 x 7.7 mm machine gun on later models
Bombs: 100 kg (220 lbs)
Japanese losses mounted but despite this they claimed 1,340 aircraft (six times the admitted Soviet losses and three times as many as Soviet aircraft admitted to being in the theatre), though similar discrepancies were common worldwide before gun cameras became widespread. Japanese losses numbered 120 (including Ki-10s) while the Russians claimed 215 vs. a peak Japanese strength of 200 fighters.
Top scoring pilot of the incident and top scoring IJAAF pilot on the Ki-27 and overall World War II IJAAF ace was Warrant Officer Hiromichi Shinohara, who claimed 58 Soviet planes (including an IJAAF record of 11 in one day) whilst flying Ki-27s, only to be shot down himself by a number of I-16s on 27 August 1939.
The preference of Japanese fighter pilots for the Ki-27's high rate of turn caused the Army to focus excessively on manoeuvrability, a decision which later handicapped the development of faster and more heavily armed fighters. The Ki-27 served until the beginning of World War II in the Pacific, escorting bombers attacking Malaya, Singapore, Netherlands East Indies, Burma and the Philippines (where it initially fared poorly against the Brewster F2A Buffalo).
The type also saw extensive action against the American Volunteer Group in the early months of the war. Soon outclassed by the American Curtiss P-40 Warhawks, the Ki-27 was replaced in front line service by the Nakajima Ki-43, while surviving examples continued to serve as a trainer.
The Ki-27 was also exported for use with Manchukuo and Thai armed forces, seeing combat with both. In Thai service, Ki-27s reportedly damaged two North American P-51 Mustangs and shot down one Lockheed P-38 Lightning.
In the final months of the war, desperate lack of aircraft forced the Japanese to utilize all available machines and the Ki-27 and 79 were no exception. Some were equipped with up to 500 kg (1,100 lb) of explosives for kamikaze attacks, but some were redeployed as fighters, suffering terrible losses as on 16 February 1945 when the 39th Educational Flight Regiment scrambled 16 Ki-79 trainers from Yokoshiba Airfield to oppose a massive air raid from U.S. Task Force 58 carrier group, losing six aircraft with more damaged and five pilots killed, in return damaging at least one Hellcat and possibly downing a second.