The Nakajima Ki-44 Shoki

Allied codename 'Tojo'

Japan
Japan

Sorry, No ID pictures yet

The Shoki (Demon or Devil Queller) was the first and only specialised interceptor of the Imperial Japanese Army Air Force. Specifically built as such, the design started in the period immediately after Nakajima’s start on the creation of the Ki-43 Hayabusa as an exceptional air-combat fighter optimized for the dogfighting role. At this time the Imperial Japanese Army Air Force decided, in a major turnaround of its operational philosophy, that it also needed an interceptor in which agility would be sacrificed to speed and climb rate. Issued to Nakajima, the Imperial Japanese Army Air Force’s requirement called for a fixed forward-firing armament of 2 × 0.5 in (12,7 mm) and 2 × 0.303 in (7,7 mm) machine guns, a maximum level speed of 373 mph (600 km/h) at 13,125 ft (4.000 m), and a climb to 13,125 ft (4.000 m) in 5 minutes 0 seconds.
The team that was tasked with the design was headed by T. Koyama, who soon decided that the requirement could be achieved only by use of an engine more powerful than the Nakajima Ha-25 (Army Type 99) radial unit, rated at 950 hp (708 kW), that was currently the standard for fighters of the Imperial Japanese Army Air Force. Koyama opted for another Nakajima radial piston engine, the Ha-41 (Army Type 100) unit, rated at 1,250 hp (932 kW). This had been developed primarily for bomber applications and was a two-row unit of moderately large diameter, but the design team managed to design this engine into a finely contoured fuselage of very modest cross section except at its forward end.
In an effort to keep weight to a minimum the length of the fuselage was kept to the shortest figure possible, and to ensure adequate directional stability this meant that the rear fuselage was given considerable depth and the vertical tail surface was located to the rear of the horizontal surface. This latter was of fairly small area, as was the inevitably highly loaded wing, which was a cantilever structure fitted in the low-set position. The wing was dihedraled, tapered in thickness and chord, and carried on its trailing edges the standard combination of outboard ailerons and inboard flaps, the latter being of the split ‘butterfly’ type with a combat setting for improved turning performance. The airframe was of all-metal construction with a light alloy stressed-skin structure except for the control surfaces, which were framed in light alloy and covered with fabric. The airframe was completed by the landing gear, which included wide-track retractable main units that retracted inward for the wheels to rest in wells that were created by forward bulges in the leading edges of the wing roots.
The Imperial Japanese Army Air Force ordered three Ki-44 prototypes (Ki stands for Kitai, which means Airframe) , and the first of these made its maiden flight in August 1940 with a raised three-section canopy (fixed front and rear sections with a sliding central part), provision under the fuselage for one drop tank, and a powerplant of 1 × Ha-41 radial engine rated at 1,200 hp (895 kW) for take-off and 1,260 hp (939.5 kW) at 12,140 ft (3.700 m) and driving a three-blade metal propeller of the constant-speed type. Early trials showed that the new type’s handling in the air was good, despite its high wing loading, but that performance was well below that required. Nakajima then embarked on a program of major modification to the rigidity of the engine mounting, the shape and area of the supercharger air inlet, the cowling flaps, and the engine cooling arrangements. With all these changes the speed of the prototypes was increased to a level that suggested that a fully equipped production model would be only 3,5% below that specified, rather than the figure of 8,3% that had been recorded at the beginning of the flight test program.

Version list:

Further pictures:

Nakajima Ki-44 Shoki ready for take-off
Nakajima Ki-44 Shoki ready for take-off

 

Technical data on the Nakajima Ki-44-Ia Shoki
Powerplant 1 × Nakajima Ha-41 Army Type 100 fourteen-cylinder air-cooled radial, rated at 1260 hp (939.32 kW) Role during war
  • Fighter
Length 28 ft 8.5 inch Height 10 ft 8 inch
Empty weight 4286 lb Operational weight 5622 lb typical,
6363 lb max
Wing Span 31 ft 0.06 inch Wing Aspect ratio 5.95
Wing Area 161.458 sq ft Service ceiling 35500 ft
Maximum speed 360 mph at 12140 ft Cruising speed 249 mph at 13125 ft
Initial climb rate Climb to 16,405 ft in 5 min 54 sec Range 575 miles typical,
1070 miles max
Fuel capacity internal unknown Fuel capacity external Up to 57 Imp gal (68 US gal) in two underwing drop tanks
Machine guns
  • 2 × 0.303 inch Type 89 fixed forward-firing in the nose
  • 2 × 0.50 inch Type 1 (Ho-103) fixed forward-firing in the wing leading edges.
Cannons -
Bomb load -Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) August 1940 Operational Service Summer 1942 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 1,225 total, 40 Ki-44-I's
Metric system
Length 8.75 m Height 3.25 m
Empty weight 1944 kg Operational weight 2550 kg typical,
2886 kg max
Wing Span 9.45 m Wing Aspect ratio 5.95
Wing Area 15 m² Service ceiling 10820 m
Maximum speed 579 km/h at 3700 m Cruising speed 401 km/h at 4000 m
Initial climb rate Climb to 5.000 m in 5 min 54 sec Range 925 km typical,
1722 km max
Fuel capacity internal unknown Fuel capacity external Up to 260 liters in two underwing drop tanks
Machine guns
  • 2 × 7,7 mm Type 89 fixed forward-firing in the nose
  • 2 × 12,7 mm type 1 (Ho-103) fixed forward-firing in the wing leading edges.
Cannons -
Bomb load -Torpedoes/rockets -

Technical data on the Nakajima Ki-44-IIb Shoki
Powerplant 1 × Nakajima Ha-109 Army Type 2 fourteen-cylinder air-cooled radial, rated at 1520 hp (1133.14 kW) Role during war
  • Fighter
Length 28 ft 9.875 inch Height 10 ft 8 inch
Empty weight 4643 lb Operational weight 6094 lb typical,
6598 lb max
Wing Span 31 ft 0.06 inch Wing Aspect ratio 5.95
Wing Area 161.458 sq ft Service ceiling 36745 ft
Maximum speed 376 mph at 17060 ft Cruising speed 249 mph at 13125 ft
Initial climb rate Climb to 16,405 ft in 4 min 17 sec Range 805 miles typical,
1056 miles max
Fuel capacity internal unknown Fuel capacity external Up to 57 Imp gal (68 US gal) in two underwing drop tanks
Machine guns
  • 2 × 0.50 inch Type 1 (Ho-103) fixed forward-firing in the nose
  • 2 × 0.50 inch Type 1 (Ho-103) fixed forward-firing in the wing leading edges.
Cannons -
Bomb load -Torpedoes/rockets -
Crew 1Naval or ground based Ground
First flight (prototype) August 1940 Operational Service Summer 1942 - 1945
Manufacturer Nakajima Hikoki K.K. Number produced 1,225 total, 8 + unknown number out of 1.167 Ki-44-II's and Ki-44-III's Ki-44-I's
Metric system
Length 8.79 m Height 3.25 m
Empty weight 2106 kg Operational weight 2764 kg typical,
2993 kg max
Wing Span 9.45 m Wing Aspect ratio 5.95
Wing Area 15 m² Service ceiling 11200 m
Maximum speed 605 km/h at 5200 m Cruising speed 401 km/h at 4000 m
Initial climb rate Climb to 5.000 m in 4 min 17 sec Range 1295 km typical,
1699 km max
Fuel capacity internal unknown Fuel capacity external Up to 260 liters in two underwing drop tanks
Machine guns
  • 2 × 12,7 mm Type 1 (Ho-103) fixed forward-firing in the nose
  • 2 × 12,7 mm Type 1 (Ho-103) fixed forward-firing in the wing leading edges.
Cannons -
Bomb load -Torpedoes/rockets -

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

Different versions of the Nakajima Ki-44  Shoki
Nakajima Ki-44 Shoki prototypes and pre-production aircraft The prototypes were delivered in quick succession in August 1940 and later. From the start these aircraft had a cockpit canopy in three sections, with fixed front and rear sections and a sliding middle section. The prototypes all had the radio mast mounted in the cockpit, later models didn't. As suche, they also had a fixed tailwheel, rounder rudder like the Ki-43 and a single drop-tank rack under the fuselage.
All requirements were met, except the speed requirement. In an effort to increase speed the rigidity of the engine mounting was increased, the shape and frontal area of the superchargers' intake (six times), and the cowling flaps. With these changes speed was improved, but the requirement wasn't met still. Then the firewall intsallation was modified to improve engine cooling so that the five cooling vents could be dispensed with.. Without armament, the Shoki finally exceeded the speed requirement, attaining 389 mph (626 km/h).
The succesfull completion of the tests prompted the production of seven pre-production aircraft, all incorporating the latest modifications. An additional change on these aircraft was the cockpit canopy, which was a two-piece type, where the rear section slided backward. The radio mast had to be replaced, and was mounted on the forward starboard fuselage. The rudder was redesigned as well, and provisions were made for two (in stead of one) drop-tanks under the wings.
Number built: 3 + 7
Nakajima Ki-44-Ia Shoki This version was identical to the aircraft of the pre-production batch.
Number built: unknown out of 40
Nakajima Ki-44-Ib Shoki This version was identical to the Nakajima Ki-44-Ia Shoki, except with respect to it's armament. The armament of this version was 2 × 0.50 inch (12,7 mm) Type 1 Ho-103 guns in the wings, and 2 × 0.50 inch (12,7 mm) Type 1 Ho-103 guns in the upper nose. Also, the oil-cooler was removed from inside the cowling and placed under the cowling gills.
Number built: unknown out of 40
Nakajima Ki-44-Ic Shoki This version was almost identical to the Nakajima Ki-44-Ib Shoki, apart from the transfer of the lower hinged portions of the main wheel fairings from the legs to the fuselage. Only a few -Ic were built.
Some aircraft from the Ki-44-I series were fitted with experimental contra-rotating two-bladed metal propellers. Since none of the later aircraft had such propellers, it can be deducted that the tests were unsatisfactory.
Number built: unknown out of 40
Nakajima Ki-44-II Shoki At the time of service entry, the Shoki was the fastest fighter of the Imperial Japanese Army Air Force. Still, it was not able to intercept the Mitsubishi Ki-46 'Dinah', so speed and rate of climb needed to be increased. The obvious solution would be to install a larger engine, and the powerplant was selected to be 1 × Nakajima Ha-109 Army Type 2 radial, rated at 1,520 hp (1.133 kW) at take-off. As an added bonus, the diameter of the new engine was identical to the existing engine, the Ha-41, so installation was rather simple. Five prototypes and three pre-production aircraft were built.
Number built: 5 + 3
Nakajima Ki-44-IIa Shoki After the Nakajima Ki-44-II Shoki prototypes and pre-production aircraft a few -IIa version aircraft were built. These were armed with 2 × 0.303 inch (7,7 mm) Type 89 synchronised guns, and 2 × 0.50 inch (12,7 mm) type 1 Ho-103 guns in the wings.
Number built: unknown out of 1.167 Ki-44-II's and Ki-44-III's
Nakajima Ki-44-IIb Shoki This version was identical to the Nakajima Ki-44-Ic Shoki, except for the newer powerplant. It was the first real mass-produced version
Number built: unknown out of 1.167 Ki-44-II's and Ki-44-III's
Nakajima Ki-44-IIc Shoki This version was the first heavily armed interceptor. Most aircraft were armed with 4 × 20 mm Ho-3 cannon, but some were armed with 2 × 0.50 inch (12,7 mm) Type 1 Ho-103 guns plus 2 × wing-mounted 40 mm Ho-301 cannon, 10 rounds each.
The Ho-301 was a light cannon, but had only a very low muzzle velocity as well. This meant that the effective range was a mere 150 yards (137 m). To increase the effectiveness, the Ho-301's were replaced by 2 × 37 mm Ho-203 cannon, which had an effective range of 1,000 yards (914 m).
A small number o Ki-44-II's were fitted with individual exhaust stacks, which provided a little extra thrust.
Number built: unknown out of 1.167 Ki-44-II's and Ki-44-III's
Nakajima Ki-44-IIIa Shoki The final development of the Shoki was powered by 1 × Nakajima Ha-145 eighteen-cylinder air-cooled radial, rated at 2,000 hp (1.491 kW). These engines were standard fitted with individual exhaust stacks providing thrust augmentation. Since the aircraft had become much more heavy the take-off and landing characteristics suffered. To counter these effect the wing area was increased to 204.514 sq ft (19 m²), and tail surfaces were increased as well. This subversion of the Ki-44-III was armed with 4 × 20 mm Ho-5 cannon. Only a few were built.
Number built: unknown out of 1.167 Ki-44-II's and Ki-44-III's
Nakajima Ki-44-IIIb Shoki This subversion was identical to the Nakajima Ki-44-IIIa Shoki, except it's armament. It was armed with 2 × 20 mm Ho-5 cannon, plus 2 × 37 mm Ho-203 cannon in the wing. Only a few were built.
Number built: unknown out of 1.167 Ki-44-II's and Ki-44-III's
Army Type 2 Single-seat Fighter Model 1A Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-Ia Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 1B Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-Ib Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 1C Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-Ic Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 2A Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-IIa Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 2B Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-IIb Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 2C Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-IIc Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 3A Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-IIIa Shoki 'Tojo'
Army Type 2 Single-seat Fighter Model 3B Shoki Official Imperial Japanese Army Air Force designation for the Ki-44-IIIb Shoki 'Tojo'

Operational remarks:

The Shoki was first met in action over China. Later it was encountered on most home-defense routes, battling in the end even with Boeing B-29 Superfortresses. As such it was one of the few Japanese types that were able to intercept and destroy the Superfortresses.
In China, Malaya and Burma it was used as defensive fighters, and in Sumatra it was specifically tasked with the protection of the vital oil fields at Palembang. Atthe end of the War the Ki-44 was mostly phased out of first-line service. They were used until the last by for example the 47th Sentai. This Sentai had quite a reputation when in November 1944 one of its Chutais (the Shinten Seikutai) was formed as an air-to-air kamikaze unit specialised in ramming attacks. The situation must have been desperate, since trading one plane for another is generally considered to be a bad tactical decision when the enemy has a lot more aircraft…

Strengths:

Weaknesses:

 

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