THE AIRCRAFT THAT STARTED THE WAR(Bomber-torpedo bomber Nakajima B5N). The first mention of the Japanese torpedo bombers appeared almost a hundred years ago – in April 1916, when at an aircraft factory Naval Arsenal in Yokosuka, was designed by the first aircraft of this type. In its development, took an active part Navy Lieutenant Chikuhei Nakajima, the future head of the eponymous Japanese company. However, the domestic aircraft do not generate interest from the Navy, which chose to seek the assistance of foreign experts.

The design of the torpedo was entrusted to the engineer Herbert Smith, who worked at that time on the firm Mitsubishi. Prior to its introduction in Japan, he participated in the design of airplanes, the British company Sopwith, so it is not surprising that as a result of armed Japanese naval aviation was a torpedo bomber Mitsubishi Round 10 (brand designation -“Product 1MT1N”), designed according to the scheme “Triplane”.

1MT1N first flight took place on August 9, 1922, and this day can be considered the birthday of the Japanese torpedo aircraft. Prototype took to the air from the factory airfield of the English test pilot William Jordan. In November of the same year, flights on the first and second prototype torpedo had made the pilots of the Japanese Navy.

1MT1N was the only one in the history of world aviation carrier-based torpedo bomber, made by Triplane composition scheme. Although it was built specifically for deployment on the deck of an aircraft carrier, large size Triplane composition of the box wing is not allowed to place the aircraft in a relatively small space ship hangar. Therefore, the total number of cars built did not exceed two dozen, and the mass production of torpedo stopped after a year.


Bomber-torpedo bomber Nakajima B5N

Bomber-torpedo bomber Nakajima B5N



Mitsubishi Tour 10 (1MT1N)- the first carrier-based torpedo bomber serial Japanese naval aviation, 1922

Mitsubishi Round 10 (1MT1N)- the first carrier-based torpedo bomber serial Japanese naval aviation, 1922

Given their mistakes Herbert Smith designed the more successful torpedo bomber biplane Mitsubishi Round 13 (В1М), which was launched in the series and became the main Japanese carrier-based torpedo bomber of the late 1920s – early 1930s years. It was built over 250 of these aircraft.

In 1932, came into service of the Mitsubishi torpedo Round 89-1 (В2М1) in the amount of 204 cars. They were followed by a series of torpedo-bombers Yokosuka Round 92 (B3Y), consisting of 129 units. As В1М, Yokosuka aircraft company had British roots – it was developed by the designer of Blackburn George petty. And in 1936 a line of biplanes finished a series of 205 torpedo-bombers Yokosuka Tour 96 (B4Y).

In the second half of the 1930-ies the biplane was considered an obsolete scheme for the aircraft, and the naval command, addressed to aviation firms to develop carrier-based torpedo monoplane. Your requirements outlined in military specification 10-Shi indicated that the aircraft was to have a wingspan of not more than 16 meters and can carry standard aircraft torpedo mass of 800 kg or two 250 kg bombs. The maximum speed of flight of the machine was to be not less than 333 km/h, a climb of 3000 meters 13 minutes, the flight duration was at least seven hours with no suspensions or four hours with a torpedo or two bombs.

Specific requirements for the torpedo deck as the aircraft was in the presence of brake hook, brakes on the main landing gear and folding wings. As power plant designers were offered the engines Nakajima Hikari or Mitsubishi Kinsei 2. The crew was to consist of three: pilot, Bombardier-Navigator and radio operator-gunner.

The competition was attended by Mitsubishi and Nakajima.

The Nakajima firm to develop a competitive aircraft were managed by the engineer, Katsujiro Nakamura. The project got a brand new working title “the product”. To obtain high performance, meeting the requirements of specification 10-Shi, the aircraft was supposed to use a lot of advanced technical solutions, including retractable landing gear and three-bladed variable-pitch propeller. The wing was planned to fold hydraulically. It was also assumed that the installation plane of the flap Fowler, who was considered at that time the most effective means of mechanization of the wing, allows to obtain high takeoff and landing characteristics.

As power plant engineers used 9-cylinder single row radial engine of air cooling Hikari 2 700 HP

The construction of the prototype aircraft was completed in December 1936. 18 Jan 1937, test pilot Takahashi lifted the car up in the air. Flight tests were hard, were affected by a significant technical novelty of the project. The trouble began almost immediately, with the broken chassis for taxiing on January 25. The aircraft received minor damage and was soon repaired. Then troubles started coming one after another, but the engineers decided their sometimes quite simply, phasing out of new products in favor of improved machine reliability and simplify its design.

First, the designers have abandoned the hydraulic folding mechanism of the wing – as it turned out, when the wind is strong hydraulics did not provide rigid fixation of the wing and it could break. Was then dismantled Fowler flaps and are fitted with slotted flaps. Tests showed that the release of the Fowler flaps, gliding on the rails, sometimes stuck in intermediate position.

All changes were made in the second prototype of the aircraft. In addition to the above, it is equipped with a different engine – 770-horsepower Nakajima Hikari 3.

After the construction of the second copy was presented at the comparative tests with competitor Mitsubishi, created the machine in accordance with the program 10-Shi and, in General, is not much different from the Nakajima aircraft company, but looking a few more conservative. The wing was elliptical in shape, the landing gear were not removed, but simply covered with fairings. The only advantage of the design was the power plant with Mitsubishi Kinsei engine capacity of 1000 HP, which provided some of the best takeoff and landing performance, and possibly even greater speed.

Comparative tests of the aircraft were carried out within three months. It turned out that both machines fully meet the requirements of the specifications of Yu-Shi. While the aircraft company Nakajima was more technologically advanced, better suited for mass production. However, the story of the refusal of the advanced design solutions is somewhat tainted his reputation.

Mitsubishi aircraft is characterized by simplicity of design and operation is affected by the absence of the hydraulic system and the presence of a fixed landing gear. However, these “advantages” that we can count and shortcomings. As for flight characteristics, due to the retractable landing gear maximum speed Nakajima was 20 km/h more than the Mitsubishi. The remaining parameters were approximately equal.

In November 1937, given the approximate equality, competition Commission made a wise decision in recommending for series production, both cars. It was considered that a more robust fixed landing gear Mitsubishi will allow the aircraft to operate from unpaved airfields ground. Torpedo bomber Nakajima company received the designation B5N1 (or Round 97-1), and Mitsubishi – В5М1 (or Round 97-2).

Mass production B5N1 was deployed at the plant in the town of Koizumi. The first prototype of the aircraft rolled out of the gate of the Assembly shop April 5, 1938. Production cars had some differences from the prototype. They were reinforced landing gear, and starting with the 50-series cars powerplant steel complete propeller of constant pitch, starting with the 123rd aircraft instead of a mechanical emergency gasoline pumps were installed more reliable manual.

The fuselage was a monocoque with riveted, smooth skin. Engine mount was welded together from steel pipes. The wing is trapezoidal in plan forms had Duhan-Giannou design with running covering. The design of the tail is metal, trim, control surfaces fabric. Main landing gear and brake hook retracted hydraulically. Landing gear was in a niche in front of the wing spar, and a hook were drawn to the tail part of the fuselage.

The crew of three were located according to the scheme “tandem” in a long, fully glazed cabin. Defensive armament consisted of a single 7.7 mm machine gun Round 92. To the holder under the fuselage can be suspended one 800-kg torpedo, one 800-kg bomb, three 250-kg bombs or six 60 kg bombs.


On the basis of the B5N1 has released 30 uchebniy aircraft B5N1-K, is intended for training of pilots. Their only difference from the war machines was the availability of dual control, the instructor was in the cockpit of the Navigator-Bombardier.


Nakajima B5N Kate

Bomber-torpedo bomber Nakajima B5N Kate:

1 – three-blade metal variable-pitch propeller; 2 – hood; 3 – canopy canopy; 4 – sliding part of the cockpit canopy; 5 – sliding part of the canopy of the Navigator; 6 – sliding part of the canopy arrow; 7 – tail wheel; 8 – the “tongs” of the torpedo; 9 – exhaust pipe; 10 – wing in the folded position; 11 – Nakajima Hikari engine; 12-front of the main chassis; 13-lower cabin Windows Navigator; 14-steering wheel height; 15-tor-moznoirc; 16-the flap; 17-Aileron; 18 – wing aeronautical fire; 19-absorber; 20 – fork tail wheel; 21 – tail wheel; 22 – the pilot seat; 23 – handle height adjustment; 24 – trimmers rudder; 25 – antenna radar N-6; 26 – caps of the filling openings of fuel tanks; 27 – cable the radio antenna; 28 – aircraft torpedo caliber 457 mm; 29 – retaining cables; 30 – thruster; 31 – spinner; 32 receiver air pressure; 33 – defensive machine gun Round 92 caliber 7.7 mm; 34 – wheel main landing gear; 35 – cooling jacket of the engine; 36 – the handle of the folding mechanism of the wing

At the end of 1938 on the B5N1 was replaced by the motor. Nakajima by this time completed its 1000-horsepower 14-cylinder two-row air-cooled engine NKIASakae 11. Increase the capacity of the power plant had a beneficial impact on the flight characteristics of the aircraft. Thus, the increase of the horizontal velocity was 9 km/h, and the altitude of 5000 m, the plane began to climb to 90 faster, increased slightly and the ceiling. In addition, the reliability Sakae 11 was higher than the Hikari, which was especially important in offshore operations. The new engine of smaller diameter made it possible to improve the view forward and down from the pilot’s seat. Its only drawback is increased fuel consumption, which range B5N1 decreased by 267 km.

Serial production of the aircraft with the Sakae 11 under the designation “carrier-based bomber-torpedo Round 97-3,” or B5N2 was deployed in December 1939. Later, when changing of a marking system, the machine received index Round 97 Model 12. By early 1941 the new modification completely replaced in combat units old B5N1.

Nakajima B5N1

Nakajima B5N1

Some B5N2 used as anti-submarine patrol aircraft. Them to search for surface vessels and submarines in surface position to establish a radar station of the type H-6 antenna it was placed on the sides of the fuselage and the wing leading edge.

Part of the B5N1 and B5N2 converted for target towing or training gliders Yokosuka Chikara.

During the serial production firm Nakajima factories at Koizumi and OTA collected 802 instance B5N first and second modifications.

In 1942, the licensed production B5N2 developed on the factory of the company in the Aichi Eitoku, and at the 11th naval aviation Arsenal at Hiro. All these plants produced about 450 cars.

In the American classification of the Japanese aircraft B5N called Kate.

Combat use

The first combat sorties of torpedo-bombers B5N was held in late 1938 in China. The aircraft, which was part of the 12th and the 14th Kokutai was used for air support of Japanese army units.

In the autumn of 1940 by agreement with the French Vichy government, Japanese troops moved into French Indochina, and a small number of B5N operated from French airfields, attacking targets in the South of China.

The real fame came to the plane the next day after the defeat of the American fleet in pearl Harbor.


For the attack on the American base the Japanese used six aircraft carriers – Akagi, Kaga, Shokaku and Zuikaku carried 27 B5N (plus three backup machines in each), a Soryu and Hiryu – 18 B5N (plus three redundant). Before the RAID the Japanese have really done the job as training flight personnel and modernization of aircraft armament. Standard aircraft torpedoes supplied extra wooden fins that allowed them to apply in shallow water, and also created a special armor-piercing bombs for attacks on American battleships. They were the 800-pound shells from 406-mm guns, to which is welded the stabilizers.

In the first shock wave was 89 B5N. Forty of them were carrying the modified torpedoes, and the rest by one armour-piercing bomb. Commanded the strike group captain Mitsuo Fuchida flying at B5N2 in camouflage color with tail number AI-301. In his memoirs he described the start of the attack: “the Sky over pearl Harbor was clear. Here, at last, visible and the harbour itself. Over it hung a light haze of the morning mist. I carefully watched through binoculars ships, peacefully at anchor. Yes, the battleships were in place. I counted eight of them. But our hope is that the harbour will be several aircraft carriers, did not materialize. I didn’t see any. It was 07.49 when I ordered his radio operator to transmit the command “Attack!”…


Thus, it is aboard the B5N was given the order of attack, marked the beginning of the entire Pacific war.

The second shock wave, the Japanese used 54 B5N. Armament the aircraft was clean bombings, and the targets for the planes was airfields by U.S. aircraft.

After returning to the ships B5N crews reported that the bombing attacks were 13 and 36 torpedo hits the enemy ships, and also reported about the many losses of enemy aircraft on the ground. The Americans managed to knock down only five B5N.

Further B5N took part in the fighting in all parts of the Pacific theater of operations. Aircraft used in carrier-based aircraft, and in the departments and units based onshore.

At the end of December 1941, the B5N from the aircraft carriers Soryu and Hiryu supported Japanese troops vysazhivaetsya to Wake island.

In January B5N carrier-based aircraft conducted operations in the area of New Guinea, then participated in the capture of Celebes, and then very successfully hit on a strategically important object Port Darwin in Northern Australia.

In February the bombers-torpedo bombers took part in the seizure of the Japanese Islands of Java and Sumatra.

In the spring of 1942, B5N participated in the operation to destroy the British Asian fleet in the Indian
ocean off the island of Ceylon, which ensured the smooth advance of the Japanese army in Burma and on the coast of the Bay of Bengal.


Performance characteristics Nakajima B5N

In may, the torpedo bombers took part in the battle with the American fleet in the coral sea. The B5N aircraft from the aircraft carriers Shokaku and Zuikaku damaged with two torpedoes the USS Lexington CM-2. In addition, the American ship was hit a few bombs, then it holds detonated a pair of aviation fuel and finished him off with their torpedoes, the destroyers of the escort.

In June B5N from carrier Hiryu distinguished himself at the battle of midway, twice hitting torpedoes at the American carrier Yorktown CV-5. However, send it to the bottom of the pilots failed. Damaged, the ship tried to tow to pearl Harbor for repairs, but on the way it torpedoed the Japanese submarine.

In August B5N participated in the battles in the Solomon Islands, and in October attacked the American fleet off the Islands of Santa Cruz.

On 26 October in the battle of Santa Cruz torpedo managed to get two torpedoes into the engine room of a U.S. aircraft carrier Hornet CV-8. And one of the torpedo planes was damaged by antiaircraft fire and crashed into a Board CV-8. The scene of the explosion of this plane was close to the main fuel tanks and on the ship there was a strong fire. During the re-attack B5N was in Hornet another torpedo that
together with several hits bombs almost destroyed the ship.

In 1943, the B5N began to be removed from service and replaced by new bombers-B6N torpedo bombers. Since 1944, the B5N was only used with ground-based airfields.

In February 1944, the Americans struck an air strike at the major Japanese base at Truk, which its significance was commensurate with pearl Harbor. A key role the base forced the Americans to throw at it about 500 planes from nine carriers. Despite heavy losses, the Japanese struck back at the American ships, during which one B5N was able to get a torpedo into the aircraft carrier Intrepid and incapacitate him.

Another page in the biography of the aircraft was the use of his suicide teams, which began to be actively used in the battles of Iwo Jima and Okinawa in February and April 1945.

Military life B5N ended in the North of Japan. In this area, 29 April 1944, was stationed the division of the weaponry which consisted of 13 B6N, and 20 B5N2. The unit that had been patrolling the sea area between the island of Hokkaido and the Aleutian Islands.

August 10, on the second day after the entry of the USSR into war with Japan, four B5N2 bombed military installations at Cape Lopatka in the South Kamchatka. On 14 August the Japanese command made to the allies with a proposal to conclude a truce, but hostilities continued on and on. August 18 – the start date of the Kuril landing operation, during which were occupied Kuril Islands. In these days from the Japanese troops liberated southern Sakhalin.


Trophy patrol Nakajima B5N2 Model 12

The patrol captured Nakajima B5N2 Model 12 “Kate” with radar N-6. Saipan, 1944

18 Aug four B5N2, attacking the amphibious forces of the enemy, was sunk by the Soviet minelayer (according to other sources – a minesweeper) which was the last victory of the Japanese aircraft the sea.

Combat service B5N showed that for Japanese aircraft, the aircraft became a kind of symbolic: he started the war in the Pacific, he also put her point.

A. CHECHIN, N. Food reserve was

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