Aviation of World War II

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  • Multipurpose Reconnaissance Aircraft
  • First flight: 1934
  • Nakajima

To replace the newly adopted Mitsubishi 2MR8 Type 92 army reconnaissance aircraft in 1933, the Technical Department of the Imperial Army Headquarters Kōkū Hombu signed a contract with Nakajima to develop a light aircraft capable of performing the functions of close reconnaissance and direct support of ground troops. At the same time, the requirement for maneuverability comparable to modern fighters was stipulated. Due to the fact that it was decided not to hold a traditional design competition, Kōkū Hombu sent his representative, military engineer Nario Ando, to the firm as project manager. The chief designer was the engineer of the company Nakajima Shigetoro Owada (Shigejiro Ohwada).

The original design was an all-metal polutoraplan with elliptical wings and a Nakajima "Kotobuki" radial engine. The fuselage of a monocoque design with a metal set and fabric covering, as a whole, repeated the proven design of the Type 91 fighter.

During the development process, many changes were made to the design. A new, more powerful Nakajima Ha-8 Type 94-1 "Hikari" nine-cylinder radial engine with a take-off power of 640 hp was installed.

The first three prototypes were completed in March, April and May 1934 respectively. The tests were carried out by Tai army pilots (captains) Saburo Amakasu and Yozo Fujita, along with Nakajima test pilot Kiyosho Shinomiya. During flight tests, it was determined that the fuselage should be enlarged, which was done on the fourth prototype.

The modified aircraft showed excellent maneuverability, good stability and excellent handling. It was adopted by the army in July 1934 under the designation "Army reconnaissance Type 94 model 1" or with the short name Ki-4, after which it was put into production at the Nakajima and Tachikawa factories, and a little later at the Manchurian company Manshu, where until February 1939, 333, 54 and 126 Ki-4 scouts were produced, respectively.

Structurally, the reconnaissance Ki-4 was a two-seat single-engine polutoraplan. with an all-metal monocoque fuselage. The power set of wings is mixed. Linen upholstery. The power plant is a Nakajima Ha-8 nine-cylinder radial engine Type 94-1 "Hikari" with a take-off power of 640 hp. and nominal 600 hp

Non-retractable landing gear with a tail spike. On the first production machines, the wheels were covered with fairings, which were later abandoned. The pilot and gunner-observer were located in separate cabins, each of which was equipped with a plexiglass visor. Above the cockpit in the upper wing there was a cutout that improved visibility.

Armament consisted of two synchronous fixed 7.7-mm Type 89 machine guns in the forward fuselage and two coaxial Type 89 machine guns in the rear cockpit. On machines of a later release, the shooter had a pair of Te-4 machine guns of the same caliber. In the process of serial production, bomb racks for six light anti-personnel bombs with a total weight of up to 50 kg appeared under the lower wing. The aircraft allowed dive bombing at an angle of up to 50°. Air brakes, however, were not provided.

Shortly after the start of production of the first version of the reconnaissance Type 94 model 1, an improved version of the Type 94 model 2 or "Type 94-Otsu" went into mass production, on which the previously used separate engine exhaust pipes were combined into two common wide manifolds along the sides of the fuselage . In addition, wheel fairings were removed from field airfields to facilitate the operation of the aircraft. Modification "Type 94-Otsu" was produced mainly at the Tachikawa Hikoki and Manshu Hikoki factories.

To accommodate the aircraft's ability to operate from rivers and lakes in China, the 6th prototype was fitted with a float landing gear with one central float and two supporting floats, borrowed from the E4N2 float reconnaissance aircraft. Another of the prototypes was installed on two main floats. Both options were tested at the Aviation Technical Research Institute as part of the naval Kasumigaura. But none of them was adopted due to the fact that the concept of its potential use was not clearly defined.

Nevertheless, the fleet became interested in the army scout to use it as a deck to replace the outdated C1M. This is how the modification Type 94 model 3 appeared - a deck version, the only difference from the Model 2 of which was inflatable bags placed on the sides of the fuselage to increase the buoyancy of the aircraft in the event of an emergency landing on water and the presence of a landing hook. However, the series of carrier-based vehicles of this type was limited to the production of six pieces, which were not used for long on board the Kaga aircraft carrier.

Based on the Ki-4, the Type 94-T civilian multipurpose aircraft with two seats in the rear cockpit was also produced.

Nakajima Ki-4
Crew 1
Wing span, m 12.00
Wing area, m² 30.00
Length, m 8.00
Height, m 3.40
1×PE Type 94-1 "Hikari" Ha-8
Power, hp 1 × 640
Weights, kg
Empty weight 1,678
Gross weight 2,500
Maximum speed, km/h 300
Cruise speed, km/h 262
Maximum rate of climb, m/min 333
Service range, km 800
Servuce ceiling, m 8,000
4 × 7.7 mm type 89 machine guns, bombs, kg 50
Photo Description

Drawing Ki-4

Ki-4 float 2

Ki-4 float 2

Combat Use

Army reconnaissance Type 94 models I and II began to enter service from 1935, gradually replacing the old Mitsubishi Type 92 from combat units. They were used in various places in mainland China from the beginning of the 2nd Sino-Japanese incident in August 1937 of the year. Ki-4s were quite actively used as part of both army hiko rentai - mixed air regiments, and independent separate reconnaissance air squadrons - dokuri hiko-chutai, performing the functions of close reconnaissance, air fire support, operational communications and cargo delivery.

During the beginning of the Second Sino-Japanese Incident in the combat units of the first line, the Ki-4 scouts were in service with the 12th hiko rentai, as well as the 4th and 6th reconnaissance dokurutsu hiko-chutai. In total, 6 reconnaissance chutays (squadrons) were transferred to China. Two more chutai were involved from the Kwantung Army stationed in the north. True, the quantitative composition of these parts is unknown. In addition to the Ki-4 reconnaissance units, these units included Type 88 long-range reconnaissance aircraft and Kawasaki Ki-3 light bombers, not counting the older Mitsubishi Type 92 reconnaissance aircraft still in service.

The Ki-4 scouts were very active in the skies of China, which predetermined the presence of a rather high percentage of losses, mainly from fire from the ground. But meetings with Chinese aviation were not uncommon. Although, it must be said that at first, due to their high speed, excellent maneuverability and powerful weapons, the Ki-4 reconnaissance aircraft were a difficult target for the numerous but outdated Chinese aviation.

But all the less, collisions happened to me. So in the morning of September 18, 1937, the Ki-4 group stormed the Chinese troops in the Tai Yuan area. The Chinese Hawk II fighters from the 28th Fighter Group, raised to intercept, attacked the Japanese aircraft, but could not catch up with them. On the same day, around 1600, two Ki-4s from the 12th hiko rental were seen again in the same area. Seven Chinese Hawk IIs from the 28th group were raised to intercept and this time the Japanese did not manage to get away with impunity. After a long chase, the lead pair of Ki-4s, piloted by Tayi (Captain) Henaga, was shot down over Chinzen. Both crew members were killed. The second scout managed to get away. The victory over the "Japanese" was recorded by Lieutenant Lu Yin Kun, who was also wounded by the fire of the tail gunner.

But in general, at first, such cases were rare.

In 1938, the army aviation units operating in China were reorganized. In September, the 15th reconnaissance hiko sentai arrived in China, equipped with Ki-4 aircraft, in addition, in addition to the 4th and 6th reconnaissance dokuru hiko-chutai (individual squadrons), the 11th dokuru hiko-chutai operated in the central part, and in the north, the 16th, 17th and 18th reconnaissance dokurutsu hiko-chutai operated. However, taking into account the rapid qualitative growth of Chinese fighter aviation, which included Soviet-made fighters and experienced volunteer pilots from the USSR in large numbers, the Japanese command, in order to avoid heavy losses, began to gradually withdraw the Ki-4 reconnaissance aircraft from the active combat zone. In reconnaissance squadrons, they gradually began to be replaced by modern high-speed Ki-15 monoplanes.

However, numerous Ki-4s continued to serve in auxiliary units as liaison, command, and light transport aircraft for a long time. The last of them were decommissioned in 1943. And in the aviation of Manzhou Guo, individual machines met the Soviet troops in August 1945.

In general, this machine was very popular with the flight crew, having established itself as one of the best aircraft in its class, high-speed, maneuverable, tenacious, easy to maintain.

Thanks to the experience of using reconnaissance aircraft and Ki-4 light attack aircraft, the Japanese army aviation gained invaluable experience for the future by developing a tactical division of army reconnaissance aviation into Strategic Photographic Reconnaissance; Tactical short-range reconnaissance and aviation of short-range interaction with ground units. This concept was successfully used by the Japanese army aviation in all subsequent years until the end of the 2nd World War, and partly exists to this day in the Self-Defense Forces.


  • Army tactical aviation of Japan in the 20-30s. / Evgeny Aranov /
  • Japanese aviation. /A. Firsov/
  • Japanese Aircraft of the Pacific War /Rene J.Francillion/
  • Encyclopedia of military equipment /Aerospace Publishing/