The Nakajima Ki-84 Hayate (Gale) was flown in prototype form in April 1943. The Ki-84 met with immediate approval by Japanese army air force pilots, but was subjected to lengthy service trials which undoubtedly delayed its introduction to combat operations. Production of the Ki-84-1a got under way at Nakajima’s Ota plant in April 1944, pre-production aircraft having equipped the 22nd Sentai in China the previous month. Immediately afterwards 10 sentais of the Ki-84-I, codenamed ‘Frank’ by the Allies, were deployed in the Philippines to confront the advancing American forces. As a dive bomber it was capable of carrying two underwing bombs of up to 550 lb.
In an effort to accelerate production of the new fighter, Nakajima opened up a new line at its Otsonomiya plant. The Ki-84 -1b and -1c differed in armament fitted. As Boeing B-29 raids began to take their toll of Japanese cities a new ‘bomber destroyer’, the Ki-84-Ic, was produced with an armament of two nose mounted 20mm cannon and two wing mounted 30mm cannon.
In the last 17 months of war 3,382 aircraft were completed, this despite the B-29 raids and the fact that, owing to such damage at Musashi, Nakajima’s engine plant had to be transferred elsewhere.
Named after Col. Frank MacCoy, ‘Frank’ was first assigned to an unknown fighter called the T.K.4, which was later coded ‘Harry’. The ‘Frank’ was ultimately assigned to the Ki.84.
Engine One 1416kW / 1,900 hp Nakajima Ha 45/11. Length 32 ft 7 in (9.92 m) Wing span 36.8 ft (11.21 m) Height: 3.39 m / 11 ft 1 in Wing area: 21 sq.m / 226.04 sq ft Weight empty 5,860 lb (2,660 kg) Max take-off weight: 3890 kg / 8576 lb Max speed 390 mph. (630 kph) Range: 1,080 miles (1,740 km.) Ceiling: 10500 m / 34450 ft Armament 2 x 20 mm Ho5 cannon, and 2 x 12.7 mm Ho103 machine guns Bomb load 1, 100 lb. (500 kg.) Seats: 1.
Ki.84-ia Engine: Nakajima Ha.45/11 Type 4, 1900 hp Wingspan: 36 ft 10.25 in Length: 32 ft 6.5 in Height: 11 ft 1.25 in Empty weight: 5864 lb Loaded weight: 7965 lb Max speed: 388 mph at 19,680 ft Service ceiling: 34,450 ft Max range: 1815 mi Armament: 2 x 20 mm Type 5 cannon, 2 x 12.7mm Type 103 mg Bombload: 1100 lb Crew: 1
Japan’s interest in jets increased in September 1944, when the Japanese air Attache in Berlin sent a large number of detailed reports on the German Me262 program. The Japanese naval staff instructed Nakajima to develop a single seat attack bomber based on the Me 262, capable of a speed of 690 km/h (430 mph) and able to carry a small bombload.
Design started in Septem¬ber 1944 under the direction of Kazuo Ohno and Kenichi Matsumur, and the resulting aircraft resembled the Ger¬man design although somewhat smal¬ler owing to the very low power avail¬able from the early Japanese jet en¬gines. The Kikka first design studies envisaged the use of 440 lb. thrust TSU-11 units which were based on the Campini principles and employed the Hitachi Hatsukaze (Fresh wind) piston engine to drive a ducted fan compressor. However, at an early design stage the Tsu-11 was dropped in favour of the Ne-10 (TR-10) centrifugal-flow turbojet, and the 340 kg (750¬lb) thrust NE-12 (TR-12), which added a four-stage axial compressor to the front of the Ne-10. The first mock-up of the Kikka was inspected by Naval Officials on January 28, 1945, but estimated performance with the NE-12 turbo jet was uninspiring, and it was decided to make a further power plant change, supplanting the NE-12 with two 475 kg (1,047 1b) thrust powerful NE-20.
The Kikke was a single-seat twin-jet attack bomber, of all-metal construction with fabric-covered tail surfaces.
Ishikawajima NE-20 fitted on Kikka No1
These also proved inadequate and for the first flight Ne 20 axial flow turbojets were fitted; however, it was still necessary to employ an auxiliary rocket for assisted take off.
The prototype commenced ground tests at the Nakajima factory on 20th may 1945, and on 25th June the first Kikka was completed. The following month it was dismantled and delivered to Kisarazu Naval Air base where it was re-assembled and prepared for flight testing. Ground tests continued on this airfield until 13th July.
On the 7th August 1945, Lieutenant Commander Susumu Takaoka made the first flight, with a duration of 11 minutes at Kisarazu Naval Air Base. His take-off run of 2,380 ft. took 25 seconds at an all-up weight of 6,945 lb. Wind speed was 23 ft.per second. He landed in 3,280 ft.
A ceremonial official “initial” test flight was made on 11th August, four days later. For this flight, rocket assisted take off (RATO) units were fitted to the aircraft. Because their alignment had been miscalculated, the acceleration was so heavy that the nose of the aircraft came up, the tail went down and skidded along the runway. Tanaoka abandoned the take off and the aircraft was damaged when it ran off the end of the runway. Before it could be repaired Japan had surrendered and the war was over.
A second prototype was then nearing completion and manufacture of between 18 and 25 further aircraft had started. Some of these were two-seat trainers. On 15 August, the entire programme was abandoned. Production, which included versions for training, reconnaissance and air combat, had also been planned.
Kikka (1st prototype) Powerplant: two Ishikawajima Ne 20 axial flow turbojets, 475 kg (1,047 1b) thrust Wing span 10.00 m (32 ft 10 in) Length 8.125 m (26 ft 8 in) Height 2.95 m (9 ft 8 in) Wing area 13.2 sq.m (142.08 sq.ft) Empty weight 2300 kg (5,071 lb) Maximum take off weight 4080 kg (8,995 lb) Wing loading: 54.3 lb./sq. ft. Power loading: 3.7 lb./lb. s. t. Max speed sea level (est): 387mph Max speed 697 km/h (433 mph) at 10000 m (32,810 ft) Climb to 10000 m (32,810 ft) in 26 min Service ceiling 12000 m (39,370 ft) Range 940 km (586 miles) Armament: one 800 kg (1,764 lb) bomb Crew: 1
Until 1942 the Imperial Japanese Navy, like other navies, flew reconnaissance missions with aircraft designed primarily for defensive or offensive combat. In early 1942 a 17 Shi specification was issued calling for a purpose designed carrier reconnaissance aircraft, with the greatest possible speed and range.
Nakajinia’s design team under Fukuda and Yamamoto fitted a 1358kW Nakajima Homare 11 radial engine engine into the slimmest possible fuselage, and 1360 litres (299.2 Imp gal) of fuel into the small wing. The latter had a laminar flow section, and slats and tabbed Fowler flaps were used to meet the severe limit on landing speed of 70 knots (130 km/h, 81 mph).
Pilot, navigator and radio operator were seated in tandem, the navigator having cameras in the belly and ventral and side observation windows and the radio operator manning a 7.92 mm (0.31 in) Type 1 machine¬gun. The prototype flew on May 15, 1943, and altitude performance proved disappointing.
Eighteen more prototype/pre-series aircraft followed, some with the more powerful 1990 hp Nakajima NK 9H Homare 21 two row 18 cylinder engine, before the type was ordered into production in April 1944 as the Navy Carrier Reconnaissance Plane Saiun (Painted Cloud / Nakajima C6N1).
Production aircraft began to be delivered to the JNAF in august 1944 although some of the prototypes had been pressed into service some two months earlier.
After its first action in the Battle of the Marianas it was code named ‘Myrt’ by the Allies. Fitted with a drop tank it had a range of over 5300 km (3300 miles), and despite the shortfall in performance was almost impossible to catch even with a Corsair or Hellcat.
The proposed C6NI B torpedo bomber never flew, but a few aircraft were converted into C6N1 S night fighters with only the pilot and navigator and with two 20 mm (0.79 in) Type 99 cannon mounted obliquely at 30 degrees in a rebuilt rear cockpit. They had adequate speed and climb to intercept the B 29 but at night were severely handicapped by lack of radar. No radar equipped version was plan¬ned, but at the war’s end a C6N2 had flown with turbocharged NK9 L engine giving 1780 hp at 9000 m (29 530 ft) driving a four blade propeller, and this was envisaged as the power plant of an improved night fighter.
A total of 463 had been built’ when production ended in August 1945, the total including the small number of C6N1-S two-seat night-fighter conversions from C6N1 aircraft, and one C6N2 prototype with a 1476kW Homare turbocharged engine.
A Nakajima C6N1-S Saiun (MYRT) was the last aircraft shot down in World War 2. It was shot down by Lieutenant Commander Thomas Reidy of the US Navy, flying a Corsair fighter, on August 15, 1945, a day after Emperor Hirohito’s surrender announcement. The war ended five minutes later.
C6N1 Engine: 1 x Nakajima NK9H Homare-21, 1484kW / 1990 hp Max take-off weight: 5260 kg / 11596 lb Empty weight: 2968 kg / 6543 lb Wingspan: 12.5 m / 41 ft 0 in Length: 11 m / 36 ft 1 in Height: 3.95 m / 13 ft 0 in Wing area: 25.5 sq.m / 274.48 sq ft Empty weight: 6411 lb Loaded weight: 9920 lb Max. speed: 610 km/h / 379 mph at 20,000 ft Ceiling: 10740 m / 35250 ft Range w/max.fuel: 5310 km / 3300 miles Armament: 1 x 7.92mm machine-guns Crew: 3
Even as the Mitsubishi Ki 21 was entering service, the Nakajima company was issued with the Ki 49 specification early in 1938 calling for an aircraft to replace the Ki-21, capable of reaching 500 km/h (311 mph) with a range of 3000 km (1860 miles) and a bombload of 1000 kg (2200 lb). Defensive armament was to include a free 20mm (0.79 in) cannon on a dorsal mounting and a tail gun turret the latter for the first time on a Japanese landplane. It was also laid down that adequate protection for the crew members and the fuel load was to be provided.
Nakajima set to work in mid 1938 with a top level design team led by Yasumi Koyama. A mid-wing layout was selected, with a considerable dihedral on the low aspect ratio wing. The wide chord centre section accommodated six fuel tanks, three on each side of the fuselage. Good takeoff and climb were guaranteed by large Fowler type flaps. A 20 mm (0.79 in) Ho 1 cannon was mounted in the dorsal position, while single 7.7 mm (0.303 in) Type 89 guns were fitted in the nose, ventral and port and starboard beam positions and in the powered tail turret. The first prototype flew in August 1939. Its two 708kW / 1080 hp Nakajima Ha 5 Kai 14 cylinder radial engines were replaced by Nakajima Ha 41s of 932kW / 1250 hp each on the remaining two prototypes and seven evaluation aircraft delivered late in 1939. Constant speed three-bladed propellers were introduced in place of the original Hamilton Standard two pitch propellers.
The Ki 49 was accepted for service as the Army Type 100 Heavy Bomber in March the following year and made its operational debut in February 1942. Later code-named ‘Helen’ when the initial production Ki-49-I (Army Type 100 Heavy Bomber Model 1) started operations with the 61st Hikosentai in China (powered with Ha-41 radial engines).
The army, fearing heavy losses in unescorted daylight raids, tested three modified Ki 49s, intended as escort fighters. Designated Ki 58, they were fitted with improved armament and crew protection but with the bomb bays deleted. Progress was disappointing and then the Ki 43 fighter, possessing sufficient range for escort work, became available in quantity and the Ki 58 programme was abandoned. Two Ki 49 variants, designated Ki 80, were intended as prototype formation leader aircraft, but this idea was also abandoned, and these aircraft were then used to test the powerful new 2420 hp Nakajima Ha 117 radial engines.
Known in Japan as Donryu (Storm Dragon), Ki 49 Is went first to equip the 61st Sentai operating in China. During the Pacific war Ki-49s, coded Helen by the Allies, flew frequent raids over New Britain and New Guinea, also making a large proportion of the attacks on Port Darwin and Australia’s Northern Territory. Two preproduction Ki 49 IIs appeared in September 1942, powered by twin 1450 hp Nakajima Ha 109 radials. In the spring of 1942 the steps were taken to increase performance, protection and defensive firepower. The Nakajima Ki-49-IIa (Army Type 100 Heavy Bomber Model 2A), the first of the new series, was powered by two Nakajima Ha-109 radial engines with increased ratings. The aircraft was fast, well protected by 5mm armour plating and rubberized fuel cells, and heavily armed. The Ki 49 IIa was delivered to the Sentais from August 1942 onwards and the later Ki 49 IIb variant had 12.7 mm (0.5 in) Ho 103 machinguns replacing the light machine guns formerly installed in the nose, ventral and tail positions. The Ki 49 II operated mainly over New Guinea and in China, as well as being assigned to units deployed in Manchuria against an anticipated Soviet attack.
Ki-49-II
Both the Ki-49-IIa and Ki-49-IIb were in action with the 7th and 61st Sentais based in China in the summer of 1942, and made many attacks on Chungking and air bases of General C. L. Chennault’s China Air Task Force. ‘Helen’ bombers equipped the 12th Sentai, based at Medan and Sabang (Sumatra) under the 3rd Air Army, and these attacked objectives in Burma and eastern India, joining Ki-21s on some occasions in raids on Calcutta. In 1943 the Ki-49s of the 7th and 61st Sentais, now operating from Timor, attacked Darwin to face strong reaction by the Supermarine Spitfire Mk.Vs of No.1 Fighter Wing. Units equipped with Ki-49s suffered most in New Guinea, where 4th Air Army came under constant attack on its airfields at Wewak, But and Dagua after August 1943, when the RAAF and the US 5th Air Force went onto the offensive.
Ki 49s also flew many missions during the desperate Japanese defence of the Philip¬pines, and surviving aircraft, with a reduced crew of two, made suicide attacks on Allied ships. Some Ki 49 Is were fitted with detec¬tion equipment and used as antisubmarine aircraft, while others were pressed into ser¬vice as troop transports.
Six examples of the final version, Ki 49-III, were built, powered by Nakajima Ha 117 radials, each intended to provide 1805kW / 2420 hp. The engines were never really more than experimental, however, and technical prob¬lems remained unsolved. Plans for mass production of the Ki 49 III came to nothing.
In all, 819 Ki 49s of all variants were built, 769 by Nakajima at its Ota factory in Gumma Pre¬fecture and the remaining 50 by the Tachi¬kawa company.
Total production amounted to 819 aircraft.
Ki-49 prototype Engines: 2 x 708kW / 1080 hp Nakajima Ha 5 Kai 14 cylinder radial engines Hamilton Standard two pitch propellers Armament: 1 x 20 mm (0.79 in) Ho 1 cannon, 5 x 7.7 mm (0.303 in) Type 89 machine guns
Ki-49 prototype Engines: 2 x Nakajima Ha 41s of 932kW / 1250 hp Props: Constant speed three-¬bladed
Ki-49-I / Army Type 100 Heavy Bomber Model 1 Engines: 2 x Ha-41 radial, 932kW / 1250 hp
Ki 49 II / Type 100 Engines: 2 x 1450 hp Nakajima Ha 109 radials. Span: 20.42 m (67ft) Length: 16.5m (54 ft 2 in) Height: 4.25m Wing Area: 69.05 sq.m Empty Weight: 6,540 kg Gross weight: 10680 kg (23550 lb) Maxi¬mum speed: 492 km/h (306 mph) Crew: 7-8 Armament: 5 x 7.92mm Machine Gun, 1 x 20mm Ho1 Machine Gun Bombload: 1,000Kg max
Ki-49-IIa / Army Type 100 Heavy Bomber Model 2A Engines: 2 x Nakajima Ha-109 radial, 1450 hp / 1119kW Wingspan: 20.42 m / 67 ft 0 in Length: 16.5 m / 54 ft 2 in Height: 4.25 m / 13 ft 11 in Wing area: 69.05 sq.m / 743.25 sq ft Empty weight: 6530 kg / 14396 lb Max take-off weight: 11400 kg / 25133 lb Max. speed: 492 km/h / 306 mph Ceiling: 9300 m / 30500 ft Range w/max. fuel: 2950 km / 1833 miles Armament: 1 x 20mm cannon, 5 x 7.7mm machine-guns, 1000kg of bombs Crew: 8
Ki 49 IIb Armament: 1 x 20mm cannon, 5 x 12.7 mm (0.5 in) Ho 103 machine-guns, 1000kg of bombs
Ki 49-III Engines: 2 x Nakajima Ha 117 radials, 1805kW / 2420 hp.
Emphasis up to 1939 had always been on manoeuvrability, but in that year a specifica¬tion was issued calling for a fighter which could reach 600 km/h (373 mph) at 4000 m (13100 ft), climbing to that height in no more than five minutes and armed with at least four machine guns. Nakujima’s design team, led by engineer Yasumi Koyama, had the first Ki 44 prototype in the air during August 1940.
A low wing all metal cantilever monoplane, it had a deep forward fuselage tapering sharply to the tailplane, which had the fin and rudder set further back than the horizontal tail surfaces. The wing was built in three sections, with a broad centre section integral with the fuse¬lage. The undercarriage retracted inwards and the tail wheel was fully retractable. Metal stressed skin covering was employed on fuselage and wings. The combat flap intro¬duced in the Ki 43 was used on all Ki 44s built. Power was provided by a 14 cylinder two row 1250 hp Nakajima Ha 41 radial engine. Test flights were successful, although the small wing resulted in a high wing loading and a high landing speed. The Ki-44 prototypes incorporated the manoeuvring flaps that had been introduced on the Ki-43, and carried an armament of two 7.7mm and two 12.7mm machine-guns.
The first prototype was soon followed by two more, but the top speed and rate of climb were not up to specification. The super¬charger intake and cowl flaps were revised several times and every effort was made to reduce drag. Maximum speed rose to 616 km/h (383 mph) in a prototype flown without armament by chief test pilot Hayashi.
Seven service test aircraft were built and issued in September 1941 to a special operational evaluation unit, the 47th Dokuritsu Chutai (independent squadron), which flew the Ki 44 Shoki (Dragon Slayer), against the Chinese over Canton. The Ki-44 was involved in a series of comparative trials against Kawasaki’s Ki-60 prototype, based on use of the Daimler-Benz DB 601 engine, and an imported Messerschmitt Bf 109E. The Ki 44 was accepted for service in September 1942 as the Army Type 2 Single seat Fighter, which carried the same armament as the prototypes.
A total of 40 Ki 44 Is were built, including small numbers of the Ki-44-Ib, and the similar KI-44-Ic with some minor refinements. Closely resembling the preproduction aircraft, but with armament increased from two fuselage mounted 7.7 mm (0.303 in) Type 89 machine-guns and two wing mounted 12.7 mm (0.5 in) Ho 103 machine guns to four 12.7 mm weapons.
Pre-production and early production air¬raft were designated Model 1. Model 2 prototype and preproduction aircraft (eight in all) were built and tested during summer and autumn 1942. Powered by the 1520 hp Nakajima Ha 109 radial, they had limited pilot armour and fuel tank protection. There was provision for two drop tanks each with 125 litres (27.5 Imp gal) of fuel. Only small numbers of the Ki- 44-IIa were built, the variant being followed by the major production Ki-44-IIb.
A number of the Ki 44 IIc version armed with four 20 mm (0.79 in) Ho 3 cannon in place of the 12.7 mm wing guns went into service later in the war. Only in late 1943 did Tojo (the Allied codename for the Ki 44) appear in quantity on the war fronts. Its impressive rate of dive and climb 5000 m (16 400 ft) was reached in just over four minutes made them especially suitable for target defence. The 85th and 87th Sentais for example, defended the strategically important oil refineries on Surnatra. Other Sentais were deployed in the Philip¬pines in a vain attempt to stem the US tide, or based at home where they had some success against Boeing B 29 Superfortress attacks.
The final variant, Ki 44 III had ejector ¬type thrust augmented exhaust stacks (fitted also to a few earlier machines) and was powered by a 1491kW / 2000 hp Nakajima Ha 145 18 ¬cylinder engine, an increased wing area and enlarged vertical tail surfaces. Armament was either four 20 mm Ho 5 cannon or two Ho 5s and two 37 mm (1.46 in) Ho 203s. Only evaluation aircraft were completed, and snags with the new engine caused development of the Ki 44¬-III to be abandoned.
When Japan surrendered, Ki 44s still equipped three Sentais and had established a fine reputation with pilots able to exploit their good qualities, while avoiding old style dogfights in which their inferior manoeuvra¬bility became apparent. Among a number of army air force aces who made their marks flying the Ki 44, perhaps the most outstand¬ing was Colonel Yukiyoshi Wakamatsu of the 85th Sentai. He had achieved at least 18 victories before he was shot down and killed in December 1944.
A total of 1225 aircraft, including prototypes, were built up to December 1944 when production was phased out in favour of the Ki 84.
Ki 44 I Span: 9.45 m (31 ft) Length: 8.75 m (28 ft 9 in) Gross weight: 2550 kg (5622 lb) Maxi¬mum speed: 580 km/h (360 mph).
Ki 44 II Span: 9.45 m (31 ft) Length: 8.78 m (28 ft 10 in) Gross weight: 2764 kg (6093 lb) Maxi¬mum speed: 605 km/h (376 mph).
Ki-44-IIb Engine: 1 x Nakajima Ha-109 Type 2, 1133kW / 1520 hp Max take-off weight: 2995 kg / 6603 lb Empty weight: 2105 kg / 4641 lb Wingspan: 9.45 m / 31 ft 0 in Length: 8.8 m / 28 ft 10 in Height: 3.25 m / 10 ft 8 in Wing area: 15 sq.m / 161.46 sq ft Max. speed: 605 km/h / 376 mph at 17,060 ft Ceiling: 11200 m / 36750 ft Range w/max.fuel: 1700 km / 1056 miles Armament: 4 x 12.7mm machine-guns Crew: 1
Design work began on the Ki-43 in late 1937 with the Army instructing Nakajima to supersede the Type 97 Fighter Ki-27. The specifications were precise and within one year the first prototype was complete. Departing from the previous practice of selecting a suitable design by calling for competitive projects from two or more air¬craft firms, the specification was issued only to Nakajima, and required a fighter capable of reaching a maximum 500 km/h (311 mph), climbing to 5000 m (16 400 It) in five minutes, and having a range of at least 800 km (500 miles). At the same time the Ki 43 was to match Ki 27 in manoeuvrability. Two further 925 hp Nakajima Ha 25 radial engined prototypes were completed and test flown in 1939 and were ready for service trials. To meet the performance requirements further changes were still required to reduce the overall weight and improve maneuverability. The unique combat flaps were designed and handling of the aircraft was well reported on. To reduce the weight the retractable undercarriage was made from ground aluminum and the frame material changed to Alclad 24, a lighter alloy. It possessed neither armour nor self-sealing fuel tanks.
They met the army’s speed and climb requirements, but were heavy on the controls and in no way compared with the Ki 27 in manoeuvrability. Ten service test aircraft were accordingly built with various modifications incorporated in each. The development programme was successful and led to the first Ki 43 I production order. The fuselage had been redesigned with a reduced diameter, and changes were made to the tailplane and wings. Specially designed butterfly type combat flaps, tested on the service test machines, gave exceptional manoeuvrability, making the Ki 43 a formidable dogfight opponent a worthy successor to the Ki 27 with an exceptional rate of turn. Two service trials aircraft had been tested with the 1100 hp Ha105 radial, but initial production aircraft retained the Ha 25. Named Hayabusa (Peregrine Falcon) the Ki 43 went into service as the Army Type 1 Fighter. Some were produced as the Ki 43a with twin 7.7 mrn (0.303in) Type 89 machine guns. Others, which were designated Ki 43 Ib, had a 12.7 mm (0.54in) Ho 103 gun in place of one of the 7.7mm weapons.
Ki.43-I
Very little paint was applied to keep weight at a minimum and later on this was to see a large variety of colour schemes, as most Ki-43’s were sent to combat in bare aluminium, the individual units producing their own schemes of camouflage. Basic factory paint included internal corrosion protection, Hinomaru on the wings – after 1942 it became standard also on the fuselage – and the antiglare forward of the canopy. Most propellers were left bare or in dark brown prime. Individual units often colour coded the spinner and propeller to their unit colours. In Spring 1940 the two bladed wooden propeller was replaced with a metal two bladed propeller, similar to a Hamilton Standard.
Production commenced in 1941 at Nakajimas Ota plant and the Ki-43-Ia reached fighter units some six months later. The first Sentais re equipped with Ki 43s, from August 1941, were the 59th and 64th. From the first day of the Pacific war against Britain and the United States, they were in action over Malaya and Burma, in support of invading Japanese land forces, and were codenamed Oscar by the Allies. Like its navy counterpart, the Mitsubishi A6M Zero, the Ki 43 acquired a reputation of supremacy in the first months of combat.
Some 40 army Ki 43 pilots claimed each to have destroyed at least ten enemy aircraft, and even discounting a proportion of these figures, this was a formidable score. In one encounter on December 22, 1941, aircraft of the 2nd Chutai, 64th Sentai, destroyed five Australian Brewster Buffaloes for the loss of one of their own number. Allied fighters caught in dogfights with experienced Japanese pilots had little chance. Early on, the Ki 43 Ic went into production, with two 12.7mm Ho 103 machine guns, but production of the Ic was terminated after 716 aircraft had appeared.
Five prototypes of the Ki 43 II (codenamed ‘Oscar’ by the Allies) flew in early 1942, and production began in November 1942 at Nakajima’s Ota factory. The weak wing structure of early aircraft had caused a number of crashes, and the new version had a strengthened wing of slightly reduced span. The new 858kW / 1150 hp Nakajima Ha 115 engine was installed, enclosed in a longer chord cowling incorporating the supercharger air intake, which increased the top speed to 530km/h. The armament of the Ki 43 1c was retained. The Ki 43 I was vul¬nerable once it was in an enemy’s sights, and to provide some protection the Ki 43 II had fuel tanks enclosed in rubber while 13 mm (0.51 in) armour protected the pilot’s head and back. The reinforced wings had racks for two 250 kg (550 1b) bombs or 200 litre (44¬Imp gal) drop tanks. Maximum speed was greatly improved without detriment to the aircraft’s flying qualities. Range with maxi¬mum internal fuel rose from 1200 km (750 miles) to 1620 km (1000 miles) in the Ki 43 II. With drop tanks, range rose to a remarkable 3000 km (1860 miles) at 400 km/h (248 mph) cruise speed. Further modifications in the Ki-¬43 IIb model were only minor. Three Ki 43 II Kai prototypes had ejector type engine exhaust stubs in place of the conventional collector ring of Ki 43 II. Deliveries to opera¬tional Sentais began in mid 1943.
The armament consisted of 2 x 7.7 mm Type 80 machine guns initially, later to be improved to 1 x 7.7mm and 1 x 12.7mm, each with 250 rounds. The Type 2 Ki-43 saw the armament with 2 x 12.7mm and the Type 3 with 2 x 20mm Ho-5 cannons replac¬ing the 12.7mm. Racks for two bombs of 250 kg each were found on the wings, however this fighter’s main disadvantage throughout combat was to be the inadequate armament.
The Ki-43-IIb entered mass production in November 1942, first with Nakajima and six months later with Tachikawa.
The 14 cylinder double row radial engine, with a round shaped oil cooler, was one of the superior engines created by Nakajima, namely Ha-25 Type 99 rated at 980 h.p and the later improved Ha-115 power plant with a two speed super¬charger and driving a three bladed propeller. The later Ha¬il 5 air intake was moved from under the cowling to its upper lip.
Final variant was the Ki-43-III with 917kW engine and a top speed of 576km/h, but relatively few examples reached operational units. Ten Ki 43 III prototypes were followed by production Ki 43 IIIa machines from Tachikawa, who had already joined the pro¬duction programme of Ki 43 IIs, allowing Nakajima to switch entirely to production of the Ki 84 Hayate. The Ki 43 III differed mainly in its 1230 hp Ha 115 II engine. The armament was still two 12.7 mm guns.
The final version was the Tachikawa-developed Ki.43-IIIb, the first and only version to include 20mm cannon in its armament, but only two of these had been completed by VJ day.
A captured Ki 43 II had been thoroughly tested and examined in Australia, and Allied pilots were given much valuable guidance on the aircraft’s weak points. This helped to alter the balance in favour of Allied aircraft. Early on, the 50th Sentai, flying over Burma, produced outstanding Ki 43 pilots, notably Sergeant Satoshi Anabuki who scored 50 kills in 18 months, and pilots Isamu Sasaki and Yukio Shimokawa who claimed 32 and 15 victories respectively. But as the war moved against Japan, Ki 43 losses began to soar as they were confronted by improved Allied fighters and better trained pilots. Tachikawa continued to produce the Ki 43 until the end of the war. Production of all versions from all manufacturers totalled 5919. Many Ki 43s remained in first line service until August 1945. Some Sentais operated them as fighter-¬bombers, while a number were expended in kamikaze attacks.
Second only in numbers to the Navy Zero, a total of 5,919 Ki-43s including 33 prototypes and trials aircraft, code named Oscar, were manufactured between 1938 and 1945. Tachikawa built 2529.
Ki 43 prototype Engine: 925 hp Nakajima Ha 25
Ki 43 service trials Engine: 1100 hp Ha¬105 radial
Ki 43 I / Army Type 1 Engine: 925 hp Nakajima Ha 25
Ki 43a Engine: 925 hp Nakajima Ha 25 Armament: twin 7.7 mrn (0.303¬in) Type 89 machine guns. each with 250 rounds Range internal fuel: 1200 km (750 miles)
Ki-43-1 Engine: Nakajima Ha-25, 990 hp. Max speed: 495 km/h at 4,000m Cruise: 320 km/h at 2,500m Max range: 745 miles Armament: 2 x 12.7mm mg
Ki 43 Ib Engine: Nakajima Ha-25, 990 hp. Range internal fuel: 1200 km (750 miles) Armament: 1 x 7.7 mrn (0.303¬in) Type 89 machine gun, 1 x 12.7 mm (0.54in) Ho 103 gun
Ki 43 Ic Engine: Nakajima Ha-25, 990 hp. Span: 11.44 m (37 ft 6 in) Length: 8.83 m (29 ft) Gross weight: 2048 kg (4515 lb) Maximum speed: 492 km/h (306 mph) Range internal fuel: 1200 km (750 miles) Armament: two 12.7¬mm Ho 103 machine guns
Ki 43 II Engine: 858kW / 1150 hp Nakajima Ha 115 Top speed: 530km/h Range internal fuel: 1200 km (750 miles) Armament two 12.7¬mm Ho 103 machine guns
Ki 43 II Engine: 858kW / 1150 hp Nakajima Ha 115 External load: two 250 kg (550 1b) bombs or 200 litre (44¬Imp gal) drop tanks Range internal fuel: 1620 km (1000 miles) Range w/drop tanks: 3000 km (1860 miles) at 400 km/h (248 mph)
Ki 43 IIb Engine: 1 x Nakajima Ha-115, 858kW / 1130 hp Span: 10.84 m (35 ft 7 in) Length: 8.92 m (29 ft 3 in) Height: 3.27 m / 10 ft 9 in Wing area: 21.4 sq.m / 230.35 sq ft Max take-off weight: 2590 kg / 5710 lb Empty weight: 1910 kg / 4211 lb Ceiling: 11200 m / 36750 ft Range w/max.fuel: 3200 km / 1988 miles Maximum speed: 530 km/h (329 mph) at 19,680 ft Crew: 1 Armament: 2 x 12.7mm machine-guns, 2 x 250-kg bombs
Ki 43 II Kai
Ki-43-IIb
Ki-43-III Engine 917kW / 1230 hp Sakae Ha 115 II External: two 250 kg bombs Top speed: 576km/h Armament: 2 x 20mm Ho-5 cannons
Ki 43 IIIa Engine 917kW / 1230 hp Sakae Ha 115 II Armament: two 12.7 mm guns. Max speed: 358 mph.
Nakajima acquired from Douglas Aircraft in the USA licence-construction rights for the DC-2 civil transport. In 1935 a smaller, twin-engine light transport based on the configuration of the DC-2 was designed by Nakajima under the designation AT-1. This was not built, but redesign resulted in an improved AT-2 with two 580 hp / 433kW Nakajima Kotobuki 2-1 radial engines, and this was flown in prototype form on 12 September 1936.
It was an all metal low wing cantilever monoplane with slim tapered wings and tailplane and retractable undercarriage. Power was provided by two Nakajima Kotobuki 2 1 radials. Test flights began on September 12, 1936, from Ojima airfield and proved successful, only minor adjustments and modifications being neces¬sary.
The AT 2 was placed in production for civil use, fitted with later Kotobuki 41 radial engines each of 780 hp. Accommodation was provided for a crew of three and eight passengers in an enclosed cabin. A total of 32 AT 2s were delivered to Dai Nippon Koku K K (Greater Japan Airlines Company) and Manchurian Airlines for use on internal and external routes up to 1940.
In 1937 the Koku Hombu (Japanese army air headquarters) was anxious to introduce a modern transport aircraft into the air force inventory and turned to the AT 2, already established as an efficient aircraft. Designated Ki 34, deliveries began the same year and it immediately went into service as the Army Type 97 Transport.
After producing 19 of the aircraft, Nakajima turned over produc¬tion to the Tachikawa company who built a further 299 up to 1942.
Some of this total were transferred by the army for navy use, and were redesignated Navy Type AT-2 Transport (Nakajima L1N1). Both civil and military versions were allocated the Allied codename ‘Thora’, and were in use throughout the Pacific war.
Ki-34 / L1N1 Engines: 2 x Nakajima “Kotobuki-41”, 529kW Max take-off weight: 5250 kg / 11574 lb Empty weight: 3500 kg / 7716 lb Wingspan: 19.92 m / 65 ft 4 in Length: 15.3 m / 50 ft 2 in Height: 4.15 m / 13 ft 7 in Wing area: 49.2 sq.m / 529.58 sq ft Max. speed: 360 km/h / 224 mph Ceiling: 7000 m / 22950 ft Range w/max.fuel: 1200 km / 746 miles Crew: 3 Passengers: 8
Nakajima’s chief designer Yasumi Koyama had evolved an advanced single seat fighter from the company’s unsuccessful PA or Ki-11 low-wing monoplane prototype during 1934. While this private -venture low wing cantilever monoplane was still under development, Japanese army air headquarters issued a requirement to three major aircraft manufacturers, including Nakajima, for a similar aircraft in mid-1935. Nakajima responded with a single-seat monoplane fighter derived from the company’s Type P.E., which it had started to develop as a private venture.
The Ki 11 first flew in July 1936; the first prototype Ki 27, built to the official requirement, flew three months later. They differed only in detail, both being powered by a 650hp Nakajima Ha la radial engine and having a fixed, spatted cantilever single strut undercarriage. The Ki 27 had a redesigned and fully enclosed pilot’s cockpit canopy, and there were changes in the engine cowling, wheel spats and fin and rudder. A second Ki 27 prototype flew in December 1936, followed by ten pre-production aircraft. Different wing forms were tested and the Ki 27s were flown against rival prototypes Kawasaki’s Ki 28 and Mitsubishi’s Ki 33 developed from the navy A5M carrier fighter. Although achieving a maximum speed of’467 km/h (290 mph) at 4000 m (13 120 ft), it was still 15 km/h (10 mph) slower than the Ki 28 and took 28 seconds longer than its rival to reach 5000 m (16400 ft). The Ki 27 was nevertheless preferred to the Kawasaki fighter because of its outstanding manoeuvrability, due in part to the remarkable lightness of the structure and to the special aerofoil section developed by Koyama’s team.
Pre-production Ki 27s had a wing with span increased to 11.31 m (37 ft 1 in) which became standard on Ki 27a production aircraft. These appeared from December 1937 onwards, designated as the Army Type 97 Fighter. The standard engine was the Ha 1b developing 780 hp at 2900 m (9510 ft).
The original allied name assigned to the Ki.27 met in China by the CBI, “Abdul” was also called “Nate” by Col. MacCoy. The name Abdul was still caried in Naval recognition manual as late as February 1943. It was finally dropped in favour of the officially adopted “Nate”.
From spring 1938 Ki 27a fighters flew in northern China, and before the end of 1938 six Sentais (groups) newly established by the army were fully equipped with the Ki 27a. The Ki 27a model was, however, soon phased out of production in favour of Ki 27b, which had a wholly glazed pilot’s canopy and provision for two 130 litre (29 Imp gal) slipper type underwing drop tanks or four 25 kg (55 1b) bombs.
Ki.27a
Ki 27s were again in action in May 1939 when fighting broke out between Japanese and Soviet troops at Nomonhan along the border with Outer Mongolia. About 200 were ultimately engaged in full scale air battles with Soviet Polikarpov I 15bis biplanes and I 16 monoplanes. The Japanese acquitted themselves well in a most bloody conflict, and claimed many victories. The highest score of 58 enemy aircraft destroyed was claimed by Sergeant Shinobara of the 11th Sentai.
The poor state of the Allied air forces in the Far East in 1941 42 allowed Nakajima’s nimble fighter, despite its poor armament of twin synchronized 7.7 mm (0.303 in) Type 89 machine guns, to control the air over Burma, the Philippines and the Dutch East Indies. British, American, Australian and Dutch pilots all acquired a healthy respect for ‘Nate’, as the type was codenamed by the Allies, and they were careful to avoid getting entangled with it in an old style close dogfight. The Ki 27 achieved the distinction of shooting down the first Allied aircraft of the Pacific war, when an aircraft of the 1st Sentai destroyed a Consolidated Catalina flying boat of No 205 Squadron RAF while covering Japanese landings on the Malayan coast.
With the advent of newer types, Ki 27s were relegated to advanced training or home defence. In the latter role they were at a stroke rendered impotent when the Boeing B 29 Superfortress came on the scene, and as the war drew to a close, Ki 27s were adapted as suicide attackers, a number of their pilots sacrificing themselves while endeavouring to crash into enemy ships or land positions carrying a 500 kg (1100 lb) bombload.
Mansyu Kikoki Seizo K K (Manchurian Aeroplane Manufacturing Company), based in the Japanese puppet state, built 1379 Ki-27s at its Harbin factory as against 2020 built by Nakajima up to December 1942, when all production by the parent firm ceased. Production included two Ki 27 Kai prototypes, even lighter than the standard machine, which reached a maximum of 475 km/h (295 mph) during tests in summer 1940.
In 1942 Mansyu redesigned the Ki 27 as an advanced trainer which went into production the same year as the Army Type 2 Advanced trainer.
Ki-27a Engine: 1 x Nakajima Ha-1b, 529kW Max take-off weight: 1790 kg / 3946 lb Empty weight: 1110 kg / 2447 lb Wingspan: 11.31 m / 37 ft 1 in Length: 7.53 m / 24 ft 8 in Height: 3.25 m / 10 ft 8 in Wing area: 18.55 sq.m / 199.67 sq ft Max. speed: 470 km/h / 292 mph Ceiling: 12250 m / 40200 ft Range w/max.fuel: 625 km / 388 miles Armament: 2 x 7.7mm machine-guns Crew: 1
Ki-27b Engine: Hitachi Ha-1b, 750 hp Wing span: 11.31 m / 37 ft 1 in Wing area: 18.56 m2 Length: 7.53 m / 24 ft 8 in Height: 3.28 m / 9 ft 2 in Empty weight: 1110 kg / 2447 lb Loaded weight: 1547 kg / 3946 lb Max speed: 470 km/h at 3500 m Max speed: 286 mph at 16,400 ft Time to 5000m: 5m 22s Service ceiling: 12,250 m Service Range: 627 km Max range: 1100 km Armament: 2 x 7,7-mm Type 89 machine guns Crew: 1 Bombload: 220 lb
Designed by Katsuji Nakamura and Kazuo Ohno and built to an 18-Shi specification for a high-speed single-seat interceptor fighter, the Nakajima J5N1 Tenrai (Heavenly Thunder) began flight tests in July 1944.
A mid-wing monoplane with a raised canopy over the pilot’s cockpit, it was powered by two 1484kW Nakajima NK9H Homare 21 radials and had a maximum speed of 597km/h. Armament comprised two 30mm and two 20mm cannon.
Six aircraft were built, four were lost in crashes or on the ground and none were used operationally. As performance was disappointingly below specification no production resulted.
Nakajima J5N “Tenrai” Engines: 2 x Nakajima NK9H “Homare-21”, 1484kW Max. speed: 597 km/h / 371 mph Armament: 2 x 30mm cannons, 2 x 20mm cannons Crew: 1
The G10N Fugaku, was a twelve engine (six coupled pairs) heavy bomber project. Planned was a speed of 780km/h, carried 20,000kg of bombs, and a range of 19,400 km. The G10N had a weak defensive armament of four 20mm cannon in single turrets. It was in advanced stage of competition at VJ day.
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