June 1939 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. . 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 cannon) 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). 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). Japanese losses numbered 120 (including Ki-10s) while the Russians claimed 215 vs. a peak Japanese strength of 200 fighters. 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
trainers. 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 and one North American P-51 Mustang. 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 of explosives for
kamikaze attacks, but some were redeployed as fighters, suffering terrible losses. On 16 February 1945, 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
F6F Hellcat and possibly downing a second. ==Variants==