The Nakajima Ki-84 Hayate

Allied codename 'Frank'

Japan
Japan

Sorry, No ID pictures yet

The Hayate (Gale) was specifically meant as the successor of the Nakajima Ki-43 Hayabusa. It was one of the best fighters of the Japanese forces during the closing stages of the War, and was available in usefull numbers and without any teething problems.
The origins of the type can be found early in 1941, when the Ki-43 Hayabusa first entered combat and turned out to be an excellent air-combat fighter. The Imperial Japanese Army Air Force did not want to rest on these laurels, however, and decided that it must immediately start planning a successor type. Nakajima therefore received orders to start work on a new multi-role fighter characterised by long range, what was by Japanese standards a high level of protection for the pilot and fuel tanks, a fixed forward-firing armament of 2 × 20 mm Ho-5 cannon and 2 × 0.50 inch (12,7 mm) Type 1 (Ho-103) machine guns, a powerplant of 1 × Nakajima Ha-45 (Army Type 4) radial rated at 1,900 hp (1.417 kW), a max level speed of 423 mph (680 km/h) at optimum altitude, and a combat endurance of 1 hour 30 minutes at a radius of 249 miles (400 km) from base.
Nakajima entrusted the project to a team under the supervision of T.Koyama, and the design was clearly inspired in its basic configuration by the Ki-43 although with a number of features to improve its basic lines and provide higher performance. The design was therefore based on a circular/oval-section fuselage of light alloy semi-monocoque construction carrying the high-set cockpit (with a three-piece canopy including a rearward-sliding central section and providing all-round fields of vision) and the flying surfaces. These comprised a plain tail unit with metal-skinned fixed surfaces and fabric-covered control surfaces, and a cantilever low-set dihedraled wing that was tapered in thickness and chord and carried on its trailing edges the standard combination of outboard fabric-covered ailerons and inboard light alloy split flaps that possessed a combat setting for improved turning capability. It had a fully retractable tailwheel landing gear, which included wide-track main units that retracted inward. Other features of the design were the twin exhausts under the lower rear edge of the cowling, and the centerline provision for a drop tank.
The first of two prototypes made its maiden flight in April 1943 with a powerplant of one Nakajima [Ha-45] 11 (Army Type 4) radial engine rated at 1,800 hp (1342 kW) for take-off and 1,650 hp (1230 kW) at 6,560 ft (2000 m) and driving a four-blade metal propeller of the constant-speed type. The second prototype joined the flight test program in June of the same year, and initial assessment of these two machines indicated that the Ki-84 possessed very good performance and agility, even though the speed was somewhat below that specified by the Imperial Japanese Army Air Force, and lacked vices or even teething problems. The development program was facilitated by the availability of up to 83 service test aircraft built between August 1943 and March 1944 and used for the evaluation of a number of minor changes from the prototype standard.
Some of the service test aircraft were evaluated under operational conditions from October 1943, and the success of these early aircraft prompted a rapid decision in favor of large-scale production.

Version list:

Further pictures:

A captured Nakajima Ki-84 Hayate on an airfield
A captured Nakajima Ki-84 Hayate on an airfield

A captured Nakajima Ki-84 Hayate in full flight
A captured Nakajima Ki-84 Hayate in full flight

 

Technical data on the Nakajima Ki-84-Ia Hayate
Powerplant 1 × Nakajima Ha-45 (Army Type 4) 23 eighteen-cylinder air-cooled radial, rated at 1900 hp (1416.43 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • Fighter-bomber
Length 32 ft 16.5625 inch Height 11 ft 1.25 inch
Empty weight 5864 lb Operational weight 7955 lb typical,
8576 lb max
Wing Span 36 ft 10.4375 inch Wing Aspect ratio 6.01
Wing Area 226.041 sq ft Service ceiling 34450 ft
Maximum speed 392 mph at 20080 ft Cruising speed 277 mph at optimum altitude
Initial climb rate Climb to 16,405 ft in 5 min 54 sec Range 1053 miles typical,
1347 miles max
Fuel capacity internal 163 Imp gal (196 US gal) Fuel capacity external Up to 88 Imp gal (106 US gal) in two 44 Imp gal (53 US gal) underwing drop tanks
Machine guns
  • 2 × 0.50 inch Ho-103 Type 1 fixed forward-firing in the upper nose, 350 rounds each
Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 1,102 lb, carried on two underwing hardpoints, rated at 551 lb each. General disposables load consisted of:
  • 2 × 551 lb bombs (in stead of drop tanks)
Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) April 1943 Operational Service Mid-1944 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 3.514 total, unknown number out of 3.288 Ki-84-I's and Ki-84-II's this version
Metric system
Length 10.17 m Height 3.38 m
Empty weight 2660 kg Operational weight 3608 kg typical,
3890 kg max
Wing Span 11.24 m Wing Aspect ratio 6.01
Wing Area 21 m² Service ceiling 10500 m
Maximum speed 631 km/h at 6120 m Cruising speed 446 km/h at optimum altitude
Initial climb rate Climb to 5.000 m in 5 min 54 sec Range 1695 km typical,
2168 km max
Fuel capacity internal 740 liters Fuel capacity external Up to 400 liters in two 200 liters underwing drop tanks
Machine guns
  • 2 × 12,7 mm Ho-103 Type 1 fixed forward-firing in the upper nose, 350 rounds each
Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 500 kg, carried on two underwing hardpoints, rated at 250 kg each. General disposables load consisted of:
  • 2 × 250 kg bombs (in stead of drop tanks)
Torpedoes/rockets -

Technical data on the Tachikawa Ki-106 Hayate
Powerplant 1 × Nakajima Ha-45 (Army Type 4) 21 eighteen-cylinder air-cooled radial, rated at 1990 hp (1483.52 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • Fighter-bomber
Length 32 ft 7.75 inch Height 11 ft 9.3125 inch
Empty weight 6499 lb Operational weight 8598 lb typical
Wing Span 36 ft 10.4375 inch Wing Aspect ratio 6.01
Wing Area 226.041 sq ft Service ceiling 36090 ft
Maximum speed 385 mph at 21000 ft Cruising speed unknown
Initial climb rate Climb to 16,405 ft in 5 min 0 sec Range 497 miles minimum
Fuel capacity internal Probably 163 Imp gal (196 US gal) Fuel capacity external Up to 88 Imp gal (106 US gal) in two 44 Imp gal (53 US gal) underwing drop tanks
Machine guns -Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in upper nose
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
  • The second and third prototypes only had 2 cannon, but unsure is which cannon were removed
Bomb load Up to 1,102 lb, carried on two underwing hardpoints, rated at 551 lb each. General disposables load consisted of:
  • 2 × 551 lb bombs (in stead of drop tanks)
Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) April 1943 Operational Service Mid-1944 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 3.514 total, 3 prototypes this version
Metric system
Length 9.95 m Height 3.59 m
Empty weight 2948 kg Operational weight 3900 kg typical
Wing Span 11.24 m Wing Aspect ratio 6.01
Wing Area 21 m² Service ceiling 11000 m
Maximum speed 620 km/h at 6401 m Cruising speed unknown
Initial climb rate Climb to 5.000 m in 5 min 0 sec Range 800 km minimum
Fuel capacity internal Probably 740 liters Fuel capacity external Up to 400 liters in two 200 liters underwing drop tanks
Machine guns -Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in upper nose
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
  • The second and third prototypes only had 2 cannon, but unsure is which cannon were removed
Bomb load Up to 500 kg, carried on two underwing hardpoints, rated at 250 kg each. General disposables load consisted of:
  • 2 × 250 kg bombs (in stead of drop tanks)
Torpedoes/rockets -

Technical data on the Nakajima Ki-113 Hayate
Powerplant 1 × Nakajima Ha-45 (Army Type 4) 21 eighteen-cylinder air-cooled radial, rated at 1990 hp (1483.52 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • Fighter-bomber
Length 32 ft 16.5625 inch Height 11 ft 1.25 inch
Empty weight 6349 lb Operational weight 8708 lb typical
Wing Span 36 ft 10.4375 inch Wing Aspect ratio 6.01
Wing Area 226.041 sq ft Service ceiling 33800 ft
Maximum speed 385 mph at 21325 ft Cruising speed unknown
Initial climb rate Climb to 16,405 ft in 6 min 54 sec Range 621 miles minimum
Fuel capacity internal Probably 163 Imp gal (196 US gal) Fuel capacity external Up to 88 Imp gal (106 US gal) in two 44 Imp gal (53 US gal) underwing drop tanks
Machine guns -Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in upper nose
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 1,102 lb, carried on two underwing hardpoints, rated at 551 lb each. General disposables load consisted of:
  • 2 × 551 lb bombs (in stead of drop tanks)
Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) April 1943 Operational Service Mid-1944 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 3.514 total, 1 prototype this version
Metric system
Length 10.17 m Height 3.38 m
Empty weight 2880 kg Operational weight 3950 kg typical
Wing Span 11.24 m Wing Aspect ratio 6.01
Wing Area 21 m² Service ceiling 10302 m
Maximum speed 620 km/h at 6500 m Cruising speed unknown
Initial climb rate Climb to 5.000 m in 6 min 54 sec Range 999 km minimum
Fuel capacity internal Probably 740 liters Fuel capacity external Up to 400 liters in two 200 liters underwing drop tanks
Machine guns -Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in upper nose
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 500 kg, carried on two underwing hardpoints, rated at 250 kg each. General disposables load consisted of:
  • 2 × 250 kg bombs (in stead of drop tanks)
Torpedoes/rockets -

Technical data on the Nakajima Ki-116 Hayate
Powerplant 1 × Mitsubishi Ha-33 (Army Type 4) 62 fourteen-cylinder air-cooled radial, rated at 1500 hp (1118.23 kW) Role during war
  • Air superiority Fighter
  • Fighter
  • Fighter-bomber
Length unknown Height 11 ft 3.8125 inch
Empty weight 4938 lb Operational weight 7039 lb typical
Wing Span 36 ft 10.4375 inch Wing Aspect ratio 6.01
Wing Area 226.041 sq ft Service ceiling unknown
Maximum speed unknown Cruising speed unknown
Initial climb rate unknown Range unknown
Fuel capacity internal Probably 163 Imp gal (196 US gal) Fuel capacity external Up to 88 Imp gal (106 US gal) in two 44 Imp gal (53 US gal) underwing drop tanks
Machine guns
  • 2 × 0.50 inch Ho-103 Type 1 fixed forward-firing in the upper nose, 350 rounds each
Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 1,102 lb, carried on two underwing hardpoints, rated at 551 lb each. General disposables load consisted of:
  • 2 × 551 lb bombs (in stead of drop tanks)
Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) April 1943 Operational Service Mid-1944 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 3.514 total, 1 prototype this version
Metric system
Length unknown Height 3.45 m
Empty weight 2240 kg Operational weight 3193 kg typical
Wing Span 11.24 m Wing Aspect ratio 6.01
Wing Area 21 m² Service ceiling unknown
Maximum speed unknown Cruising speed unknown
Initial climb rate unknown Range unknown
Fuel capacity internal Probably 740 liters Fuel capacity external Up to 400 liters in two 200 liters underwing drop tanks
Machine guns
  • 2 × 12,7 mm Ho-103 Type 1 fixed forward-firing in the upper nose, 350 rounds each
Cannons
  • 2 × 20 mm Ho-5 fixed forward-firing in the wing leading edges, 150 rounds each
Bomb load Up to 500 kg, carried on two underwing hardpoints, rated at 250 kg each. General disposables load consisted of:
  • 2 × 250 kg bombs (in stead of drop tanks)
Torpedoes/rockets -

Here is a quick overview of all different versions, without the full technical specifications:

Different versions of the Nakajima Ki-84  Hayate
Nakajima Ki-84 Hayate prototypes There were only 2 prototypes of the Ki-84 Hayate, before a batch of pre-production aircraft was produced. The prototypes were powered by 1 × Nakajima Ha-45 (Army Type 4) 11 radial, rated at 1,800 hp (1.342 kW). Typical for these aircraft was the big exhaust collector pipe that was mounted on each side of the engine behind the cowling gills, and the tailplane that was set well ahead of the vertical surfaces.
Test progressed rapidly, and the prototypes were soon joined by Service Trials aircraft.
Number built: 2
Nakajima Ki-84 Hayate Service Trials aircraft This batch was rather large, being 83 aircraft. During production continues improvements were incorporated in the production line. From one to another there were only minor changes, but in the end a lot was improved. These improvements include fuselage changes to improve production, and the shape and size of the fin and rudder were changed in order to improve control on take-off because the aircraft suffered from propeller-induced torque. Some aircraft were fitted with two wing racks for bombs in addition to a fuselage centerline rack for a drop-tank, while other aircraft were used to test a partially-retractable ski undercarriage.
Number built: 83
Nakajima Ki-84 Hayate pre-production aircraft After the Service Trials aircraft had proven their value, a pre-production batch was built. In this series the Ki-84 received individual exhaust stacks providing some thrust, and the centerline rack for the drop-tanks was deleted in favor of adaptable wing racks that could carry either bombs or drop-tanks.
Number built: 42
Nakajima Ki-84-Ia Hayate The last of the pre-production aircraft were produced in parallel to the first true production series, the Ki-84-Ia. These aircraft were similar to the pre-production aircraft, the main difference was in the field of it's powerplant. The powerplant of early production aircraft was 1 × Nakajima Ha-45 11 or Ha-45 12, rated at 1,800 hp (1.342 kW) and 1,825 hp (1.361 kW) respectively. The powerplant of late production models was 1 × Nakajima Ha-45 21, rated at 1,990 hp (1.484 kW) for take-off.
Number built: 94 plus unknown out of 3.288 Ki-84-I's and Ki-84-II's
Nakajima Ki-84-Ib Hayate The Ki-84-Ib was almost identical to the Ki-84-Ia, except armament. The Ki-84-iB had it's 0.50 inch (12,7 mm) Type 1 (Ho-103) guns replaced with 2 × 20 mm Ho-5 cannon, totalling to four 20 mm cannon.
Number built: 94 plus unknown out of 3.288 Ki-84-I's and Ki-84-II's
Nakajima Ki-84-Ic Hayate The Ki-84-Ic was a specialised bomber destroyer, and received an armament of 2 × 20 mm Ho-5 cannon in the nose and 2 × 30 mm Ho-105 cannon in the wings.
Number built: 94 plus unknown out of 3.288 Ki-84-I's and Ki-84-II's
Nakajima Ki-84-II Hayate, or Hayate KAI This version actually received several designations, but in order to prevent confusion with the Ki-84-Ib and Ki-84-Ic (depending on armament), the Ki-84-II designation or even Hayate KAI was used.
Previous versions suffered from sudden fuel pressure loss, and the problem was only solved with a development of the Ha-45 21 that had low-pressure fule injection. This version, designated Ha-45 23, was never produced in the numbers of it's predecessor, because the plant where it was built had been bombed, and was replaced to an underground installation.
The Ki-84-II was built with either one of the following poerplants: Nakajima Ha-45 21, Nakajima Ha-45 25 or Nakajima Ha-45 23 radials.
Another new feature was the wooden rear fuselage, certain fittings and modified wingtips. Shortages of aluminium prompted the Japanese to resort to wooden parts in stead.
Number built: 94 plus unknown out of 3.288 Ki-84-I's and Ki-84-II's
Nakajima Ki-84-III Hayate The final version of the Hayate never got off the drawing board bfore the War was ended. It was planned as an high-altitude version, powered with 1 × Nakajima Ha-45 Ru, with a turbosupercharger mounted in the fuselage belly.
Number built: 0
Nakajima Ki-84N Hayate This version of the Ki-84 was meant to be a high-altitude interceptor, powered by 1 × Nakajima Ha-44 13 (Ha-219), rated at 2,500 hp (1.864 kW). Wing area was increased to 249.19 ft² (23,15 m²). This version was scheduled to go into production as the Ki-117.
Number built: unknown, probably 0
Nakajima Ki-84P Hayate This version was also meant to be a high-altitude version, powered by 1 × Nakajima Ha-44 13 (Ha-219), rated at 2,500 hp (1.864 kW). The difference lay in the wings, which area was even further increased to 263.72 sq ft (24,50 m²). This version however was abandoned in favour of the Ki-84R
Number built: unknown, probably 0
Nakajima Ki-84R Hayate This version was preferred above the Ki-84P, even though this version was less ambitious than it's (drawing-table) predecessor. it was a standar Ki-84-I airframe, coupled with 1 × Nakajima Ha-45 44, rated at 2,000 hp (1.491 kW), and fitted with a mechanically driven two-stage three-speed supercharger.
Number built: unknown, probably 0
Tachikawa Ki-106 Hayate The Hayate KAI was a partially wooden version, and in order to save even more aluminium Tachikawa was asked by the Ministry of Munitions to design a fully wooden Hayate.
Resulting from this oreder were three wooden prototypes, designated Ki-106. These aircraft were powered by 1 × Nakajima Ha-45 21, rated at 1,990 hp (1.484 kW). External differences were the vertical surfaces that had an increased area, and the smooth external finish obtained by applying a thick coat of lacquer to the plywood skin. Initially the skin-bonding proved too weak, but this problem was solved soon.
The first prototype carried four 20 mm cannon, but in order to reduce weight the second and third prototype only had two. Work was still carried out to reduce the weight of the aircraft when the War ended.
Number built: 3
Tachikawa Ki-113 Hayate This version was partially constructed with steel, which is in terms of aviation quite a heavy metal. The cockpit section was made of carbon steel, as were the ribs and bulkheads. Additionally it had steel sheet skinning.
The design was carried out in the autumn of 1944, and the prototype was completed early 1945. It was never flown though, since it was decidedly overweight .
Number built: 1
Tachikawa Ki-116 Hayate This was the final version of the Hayate that entered flight testing. It was the fourth Ki-84-I built by Mansyu Hikoki Seizo K.K., and was adated for 1 × Mitsubishi Ha-33 62 (Ha-112-II) driving a three-bladed propeller identical to those on the Ki-46-III 'Dinah'.
The new version proved very succesful, and resulted in a weight reduction of 1,000 lb (454 kg) empty weight. Final tests were being conducted when Japan finally surrendered after the two atomic bombs.
Number built: 1
Army Type 4 Fighter Model 1A Official Imperial Japanese Army Air Force designation for the Ki-84-Ia Hayate 'Frank'
Army Type 4 Fighter Model 1B Official Imperial Japanese Army Air Force designation for the Ki-84-Ib Hayate 'Frank'
Army Type 4 Fighter Model 1C Official Imperial Japanese Army Air Force designation for the Ki-84-Ic Hayate 'Frank'

Operational remarks:

From the first day that the Hayate was encountered over China, to the last day over Japan, this aircraft was respected by the Allied pilots. And with good reason, for this fighter combined most of the virtues of Japanese aircraft without the vices. It was well armed, maneuverable, well protected, and good performance.
In March 1944 the first unit operatin gthe hayate was pitted against the US 14th Air Force over China, proving that it could compete with the best of the Allied fighters. Some five weeks later these units were transferred to the Philippines, where ten Sentais (Squadrons/units) were to fight a defensive war. Outnumbered, the Ki-84's couldn't prevent the fall of the Philippines to Allied forces, and had to retreat once more. During this period the value of the Hayate was beyond any doubt, and the japanese decided to open other production facilities for it.
The production of the Hayate was put under great strain by bombings of the US 20th Air Force which operated Boeing B-29's. One of the raids destroyed the factory where most engines for the hayate were produced, and the production never reached the same levels afterwards. Also workmanship suffered from the constant draws made by the Army, which was randomly performed under even marksmen. Quality dropped sharply, but even a worsening quality couldn't throw the hayate from it's first place among the Japanese aircraft. During the Okinawa campaign and in the defense of the homeland the Hayate still was the most succesful Japanese aircraft.
After the War flight tests were conducted between Allied and japanese aircraft, and it turned out that the Ki-84 could outperform the best Allied fighters. The North American P-51D Mustang and the Republic P-47D Thunderbolt were both left behind, the first with 3 Mph (5 km/h), the second with 22 Mph (35 km/h). The speed reached by the Ki-84 was 427 Mph (687 km/h) at an altitude of 20,000 ft (6.096 m).

Strengths:

Weaknesses:

 

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© by Frans Bonné, 2000
Last revision: 9/23/01