The experimental Ki-27, equipped with the Nakajima Na-1b radial engine, a licensed reproduction of the American aircraft engine Wright R-1820-04, demonstrated exceptional flight performance, surpassing the best Soviet fighter due to the low wing loading in horizontal maneuverability - half-glider I-15 (the time of the full turn radius was 8 seconds), in terms of speed - I-16 type 10, and in terms of climb rate and tactical and technical characteristics - all aircraft of this class.

Tests of the pilot batch were successfully completed at the end of 1937, and the aircraft was launched into mass production under the designation "Type 97 Model A Army Fighter" (Ki-27a). Production machines, like the aircraft of the experimental batch, received an enlarged wing, a more familiar canopy of a canopy, a metal gargrot behind the cockpit and a new 780 hp Nakajima Na-lb engine. The fighter's armament consisted of two synchronized 7.7-mm Type 89 machine guns located above the engine. All aircraft were equipped with radios, and the aircraft of the flight commanders were equipped with transmitters.

Over time, Ki-27a was replaced by Ki-27b fighters, which differed in a canopy with improved visibility and a redesigned oil cooler; under the center section, four bombs weighing 25 kg each or two additional dropped tanks with a capacity of 130 liters could be suspended.

Based on the tests carried out at the Air Force Research Institute at the end of 1939 of the captured and repaired Ki-27, the following conclusions were drawn:

The I-97 aircraft (Soviet designation of the aircraft) had relatively high flight performance with a 650 hp engine, fixed landing gear and low landing speed. Soviet specialists substantiated this for a number of reasons.

• a fuselage midship less than that of the Red Army Air Force fighters (the star diameter of this motor is 6% less);
• metal coating with rivets flush with the wings and fuselage, in contrast to the domestic one - linen;
• smaller relative wing profile thickness (15% at the root);
• the presence of a gearbox on the motor, which improves the working conditions of the screw;
• low flight weight.
• Good takeoff and landing properties of the aircraft and maneuverability are obtained due to excellent longitudinal, lateral and directional stability - due to front centering of 25.4% of MAR; large transverse V wings (7 °) and a good choice of plumage areas.
• But on the other hand, the desire to reduce the flight weight has made it difficult to operate and transport the aircraft. In addition, the aircraft was not strong enough both in normal flights (the presence of vibrations due to the complete absence of motor depreciation) and during a dive. The vertical dive height was limited to 500-700 meters, which was the weak point of the I-97 fighter.

The new fighter received its baptism of fire in battles with Soviet aviation in the area of ​​the Khalkhin-Gol River. His appearance was a complete surprise. Soviet intelligence failed to recognize the aircraft's class by the type number, considering the unknown Type 97 to be a tactical bomber Kawasaki Ki-32 (also called Type 97) with fixed landing gear, and not a fighter. These reports did not cause concern in the Red Army Air Force Directorate, bled by mass repressions, and no preventive measures were taken.

The first collision of I-16 (type 10) and Ki-27 took place on May 27, 1939, when the squadron of the 22nd IAP met with 9 new Japanese aircraft. The result of the battle was overwhelming: from the Soviet side all 12 aircraft were lost - two pilots were killed, and the Japanese lost only one! On the same day, 10 I-15s met with 8 Ki-27s. The result was even more dramatic. Trying to hit the enemy on the bends, using the excellent maneuverability of the I-15, the Soviet pilots engaged in battle on the horizontal lines, and to their bitter amazement turned into targets. Only one red-star biplane returned to the airfield to disintegrate on landing. The rest were shot down, 5 pilots were killed. The Japanese had no losses, and thus seized air superiority. From that day on, in official reports, the new Japanese fighter was named I-97.

For Stalin, who was very jealous of the records and failures of Soviet aviation, these events became a symptom of doubts about its real combat capability. Already on May 28, a meeting was held in the Central Committee of the All-Union Communist Party (Bolsheviks), and on the 29th, aces-veterans of air battles in Spain and China, headed by corps commander Yakov Smushkevich, were sent to Mongolia. I-15bis, I-153 "Chaika" and I-16 type 24 fighters, equipped with a more powerful M-62 engine and armed with four 7.62 mm ShKAS machine guns, were sent to the conflict area. One squadron of new aircraft were sent to the conflict area: two-seater one and a half gliders DI-6, I-16P, armed with two ShVAK cannons on the wings and two synchronous ShKAS machine guns, and I-16 with RS-82 rockets.

The proportion of aircraft immediately changed in favor of the Soviet Union. Heroes of the Soviet Union Grigory Kravchenko and Ivan Lakeev were appointed at the head of 2 regiments of I-16, respectively, the still forming regiment of the latest I-153 was to be headed by Hero of the Soviet Union Sergei Gritsevets - while he was sent as deputy commander of the I-16 regiment, - and regiment I-15bis - Evgeny Stepanov. This came as an unpleasant surprise for the Japanese command, which, due to the low productivity of the Japanese aviation industry, could not oppose the Soviet aviation with the required number of Ki-27s, while the A5Ms were necessary for carrier-based aviation, in addition, after the air war in China, there were very few of them.

Smushkevich, in order to successfully counter the new Japanese aircraft, proposed to the aces, Heroes of the Soviet Union, to apply the tactics of interaction of high-speed monoplanes with maneuverable biplanes provided for by the Combat Instructions of the Red Army Air Force. But the battle on June 22, 1939, which turned out to be the largest air battle in the interwar period, showed that this tactic does not justify itself: the Japanese first dealt with biplanes, and then, using the advantage in vertical maneuver, entered the battle with the I-16. And although TASS reported in the evening that 42 aircraft were destroyed in an air battle: 31 Japanese and 11 Soviet, this raises doubts among all researchers. The ratio of losses on both sides has always been overestimated. Japanese Ki-27 pilots stated in reports that they shot down 1,252 Soviet aircraft. In the order of the People's Commissar of the USSR on awarding the 22nd IAP with the title of Red Banner, it was said that its pilots had shot down 262 Japanese aircraft during the battles. If you take an uncritical attitude to the Japanese figures, it turns out that all Soviet aviation in the conflict area was completely destroyed, and if Soviet, then the “Stalin's falcons” of only one fighter regiment “swept all new Japanese aircraft from the sky of brotherly Mongolia”! But the losses of Japanese aircraft were nevertheless sensitive. The air supremacy so easily won was lost just as quickly.

During the battles for Khalkhin Gol in 1939, the damaged Ki-27 was captured and repaired. By train, he was taken to the Air Force Research Institute in Chkalovsky, where test pilot Alexei Kubyshkin flew around him. In August 1939, training air battles were conducted with the Polikarpov I-153 fighter (according to other sources, with the I-15 bis). This time Ki-27 was piloted by Mikhail Vakhrushev. Unfortunately, these tests ended tragically - Ki-27 suddenly crashed into the ground and exploded, the pilot was killed.

Then Ki-27 participated in the invasion of Burma, Malaya, the Dutch East Indies and the Philippines and were effective until they encountered modern fighters, after which they were transferred to the air defense system of the Japanese Islands, where they served until 1943. Later they were used as training machines. At the end of the war, a number of Ki-27s were used by kamikaze pilots - the aircraft carried up to 500 kg of bomb load.

A total of 3399 Ki-27 aircraft were produced, of which 1379 under the designation Ki-79 were built at the Mansu Hikoki Seizo KK plant in Manchuria.

Photo	Description
	Drawing Ki-27a
	Ki-27b at the airfied

Bibliography

• "Encyclopedia of military engineering " /Aerospace Publising/
• "50 best fighters of World War II" /Gennadiy Kornukhin/
• "Japan Warplanes of World War II" /Oleg Doroshkevich/