The was the main

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

used by the Imperial Japanese Army Air Service up until 1940. Its Allied

nickname A nickname, in some circumstances also known as a sobriquet, or informally a "moniker", is an informal substitute for the proper name of a person, place, or thing, used to express affection, playfulness, contempt, or a particular character trait ...

was "Nate", although it was called "Abdul" in the "China Burma India" (CBI) theater by many post-war sources; Allied Intelligence had reserved that name for the nonexistent Mitsubishi Navy Type 97 fighter, expected to be the successor to the carrier-borne Type 96 (

Mitsubishi A5M The Mitsubishi A5M, formal Japanese Navy designation , experimental Navy designation Mitsubishi Navy Experimental 9-''Shi'' Carrier Fighter, company designation Mitsubishi ''Ka''-14, was a WWII-era Japanese Aircraft carrier, carrier-based fighter ...

) with retractable landing gear and an enclosed cockpit.

Design and development

In 1935, the

Imperial Japanese Army The Imperial Japanese Army (IJA; , ''Dai-Nippon Teikoku Rikugun'', "Army of the Greater Japanese Empire") was the principal ground force of the Empire of Japan from 1871 to 1945. It played a central role in Japan’s rapid modernization during th ...

held a competition between Nakajima,

Mitsubishi The is a group of autonomous Japanese multinational companies in a variety of industries. Founded by Yatarō Iwasaki in 1870, the Mitsubishi Group traces its origins to the Mitsubishi zaibatsu, a unified company that existed from 1870 to 194 ...

, and Kawasaki to design a low-wing

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

to replace the Kawasaki Ki-10 (Army Type 95 Fighter)

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

. The new fighter was to have also a better performance than the experimental Mitsubishi Ki-18. The results were the Nakajima Ki-27, the Kawasaki Ki-28, and the Mitsubishi Ki-33 (a modification of the

carrier-based fighter). The Nakajima design was based on its earlier Ki-11 monoplane fighter which lost to the Ki-10 in the Type 95 Fighter competition. When the follow-up Nakajima Ki-12 proposal with a liquid-cooled engine and retractable

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...

was deemed too complex by the Japanese officials, the Ki-27 was designed by Koyama Yasushi to have an air-cooled

radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...

and fixed landing gear. The aircraft had the Nakajima trademark wing with a straight leading edge and tapered

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

which would reappear again on the Ki-43, Ki-44, and Ki-84. The Ki-27 made its first flight on 15 October 1936. Although it had a slower top speed and worse climb performance than its competitors, the Army chose the Nakajima design for its outstanding turning ability granted by its remarkably low

wing loading In aerodynamics, wing loading is the total weight of an aircraft or flying animal divided by the area of its wing. The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading. The faster an airc ...

. The Army ordered 10 pre-production samples (Ki-27a) for further testing, which featured an enclosed cockpit with sliding canopy and larger wings. The type was officially accepted into service in 1937 as the Army Type 97 Fighter. In addition to Nakajima, the Ki-27 was also manufactured by Tachikawa Aircraft Company Ltd and Manshukoku Hikoki Seizo KK, with a total of 3,368 built before production ended in 1942.

Operational history

The Ki-27 was the Imperial Japanese Army Air Force's main fighter until the start of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. 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. Khalkhin Gol Japanese Ki 27 1939

In the 1939 Battle of Khalkhin Gol against the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

, 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 Armour (Commonwealth English) or armor (American English; see American and British English spelling differences#-our, -or, spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, e ...

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 The First American Volunteer Group (AVG) of the Republic of China Air Force, nicknamed the Flying Tigers, was formed to help oppose the Japanese invasion of China. Operating in 1941–1942, it was composed of pilots from the United States Ar ...

(likewise to fly against Japanese forces). Nakajima Ki-27 at Nomonhan

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. (Overclaiming remained commonplace through World War Two, despite gun cameras and expert intelligence assessments.) 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 Warrant officer (WO) is a Military rank, rank or category of ranks in the armed forces of many countries. Depending on the country, service, or historical context, warrant officers are sometimes classified as the most junior of the commissioned ...

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

bomber A bomber is a military combat aircraft that utilizes air-to-ground weaponry to drop bombs, launch aerial torpedo, torpedoes, or deploy air-launched cruise missiles. There are two major classifications of bomber: strategic and tactical. Strateg ...

s attacking Malaya,

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

Netherlands East Indies The Dutch East Indies, also known as the Netherlands East Indies (; ), was a Dutch Empire, Dutch colony with territory mostly comprising the modern state of Indonesia, which Proclamation of Indonesian Independence, declared independence on 17 Au ...

Burma Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and ha ...

and the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

(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 Manchukuo, officially known as the State of Manchuria prior to 1934 and the Empire of Great Manchuria thereafter, was a puppet state of the Empire of Japan in Northeast China that existed from 1932 until its dissolution in 1945. It was ostens ...

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 The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps (USAAC) by the Lockheed Corporation, the P-38 incorporated a distinc ...

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

Data from ;Nakajima Army Type 97 Fighter :Long Army designation for the Ki-27 Nakajima Ki-27 and Japanese personnel

; Nakajima Type PE : Private-venture experimental aircraft with Nakajima Ha1a engine. ; Nakajima Ki-27 : Prototype version with armament in response to IJAAF specs, two aircraft built. ; Nakajima Ki-27-Kai Prototype : Pre-production units with armament and heavier Nakajima Ha1b engine, 10 aircraft built. ; Ki-27a : First production version. Approximately 565 aircraft built. ; Ki-27a-Kai : Trainer version converted from existing production. Approximately 150 aircraft converted. ; Ki-27b (Army Type 97b Fighter) : Improved canopy, oil cooler and provision for 4 × 25 kg (55 lb) bombs or fuel tanks under the wings. A total of 1,492 built, including 50 by Tachikawa Aircraft Company Ltd. ; Ki-27b-Kai : Trainer version converted from existing production. Approximately 225 aircraft converted. ; Nakajima Ki-27-Kai : Experimental lightened version developed as an interim solution when Ki-43 development was delayed, top speed 475 km/h (295 mph); two aircraft built). ; Mansyū Ki-79 : Trainer version, built by Manshūkoku Hikōki Seizo KK with a 510 hp Hitachi Ha.13a-I or Ha.13a-III engine. A total of 1,329 aircraft built in four sub-versions (The single seat Ki-79a (Ha.13a-I) and Ki-79c (Ha.13a-III) and the two-seat Ki-79b (Ha.13a-I) and Ki-79d (Ha.13a-III)). ; Mansyū Army Type 2 Advanced Trainer :Long Army designation for the Mansyū Ki-79 ; B.Kh.12 : ()

Royal Thai Air Force The Royal Thai Air Force (RTAF) (; ) is the air force of the Kingdom of Thailand. Since its establishment in 1913 as one of the earliest air forces of Asia, the Royal Thai Air Force has engaged in numerous major and minor conflicts. During the ...

designation for the Ki-27b.

Operators

World War II

; * Manchukuo Air Force ; Reformed Government of the Republic of China * Scheduled aircraft never delivered due to distrust of Chinese forces Imperial Japanese Army 97 type fighter

; *

**Foong Bin Khap Lai 15 (15 Fighter Squadron) **Foong Bin Khap Lai 16 (16 Fighter Squadron)

Post-War

; *

People's Liberation Army Air Force The People's Liberation Army Air Force, also referred to as the Chinese Air Force () or the People's Air Force (), is the primary aerial warfare service of the People's Liberation Army. The PLAAF controls most of the PLA's air assets, includi ...

;: * Republic of China Air Force ; * In 1945,

Indonesian Air Force The Indonesian Air Force (, sometimes shortened as IDAF / IdAF) is the Air force, aerial branch of the Indonesian National Armed Forces. The Indonesian Air Force is headquartered in Jakarta, Indonesia, and is headed by the Chief of Staff of th ...

–then Indonesian People's Security Force (IPSF) (Indonesian pro-independence guerrillas)– captured a small number of aircraft at numerous Japanese air bases, including Bugis Air Base in

Malang Malang (; , ), historically known as Tumapel, is an inland List of regencies and cities of Indonesia, city in the Indonesian Provinces of Indonesia, province of East Java. It has a history dating back to the age of the Singhasari, Singhasari K ...

(repatriated 18 September 1945). Most aircraft were destroyed in military conflicts between the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

and the newly proclaimed- Republic of Indonesia during the

Indonesian National Revolution The Indonesian National Revolution (), also known as the Indonesian War of Independence (, ), was an armed conflict and diplomatic struggle between the Republic of Indonesia and the Dutch Empire and an internal social revolution during A ...

of 1945–1949.

Surviving aircraft

Two aircraft survive today: * One Ki-27 is preserved at the Tachiarai Peace Memorial Museum. * One Mansyu Ki-79 is preserved at the Satria Mandala Armed Forces Museum, Jakarta, Indonesia."Mansyu Ki-79b at the ABRI Satria Mandala Museum."
''pacificwrecks.com.'' Retrieved: 22 July 2010.

Specifications (Ki-27b)

References

Notes

Bibliography

* . * Francillon, Ph.D., René J. ''Japanese Aircraft of the Pacific War''. London: Putnam & Company, Second edition 1979, First edition 1970. . * Green, William. ''Warplanes of the Second World War, Volume Three: Fighters''. London: Macdonald & Co. (Publishers) Ltd., Seventh impression 1973, First edition 1961. . * Green, William and Gordon Swanborough. "The Agile Asian... Japan's Type 97 Fighter". '' Air Enthusiast Six'' March–June 1978. * * Green, William and Gordon Swanborough. ''WW2 Aircraft Fact Files: Japanese Army Fighters, part 2''. London: Macdonald and Janes's, 1977. . * . * Kotelnikov, Vladimir R. '' Air War Over Khalkhin Gol: The Nomonhan Incident.'' Bedford, UK: SAM Publications, 2010. . * Mikesh, Robert. ''Japanese Aircraft 1910–1941''. Annapolis, Maryland: Naval Institute Press, 1990. . * Nedialkov, Dimitar. ''In The Skies of Nomonhan, Japan vs Russia May–September 1939.''. London: Crecy Publishing Limited, Second edition 2011. . * . * Tapasanan, Vidya. "Japanese Airplanes in the Royal Thai Airforce (RTAF) Service." ''Asahi Journal No. 4/2002.'' * * (bilingual Polish/English). {{Authority control Ki-027 Ki-27, Nakajima Single-engined tractor aircraft Low-wing aircraft Aircraft first flown in 1936