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Combat Aircraft of the Pacific War

Nakajima Ki-84 Hayate'Frank'

Ki-84 of HQ Chutai, 29th Sentai in the summer of 1945

"Forget it - it's a Frank." It is said that this comment was made frequently by USAAF personnel watching radar screens on Okinawa in the closing weeks of the Pacific War.  It was customary to watch for a contact to appear and then to scramble P-51 Mustangs to intercept the enemy aircraft.  But when the blip was moving so fast that it was inferred to be one of the advanced new Japanese Hayate fighters it would be assumed that the P-51s would stand no chance of catching the intruder.

Generally regarded as the best Japanese fighter of World War Two, the Hayate{'Hurricane') was nonetheless not without its problems.  Much of its superlative all-round performance stemmed from its extremely advanced direct-injection engine, the Army's first version of the Navy NK9A.  Yet this same engine gave constant trouble and demanded skilled maintenance.

T. Koyama designed the Ki-84 to greater strength factors than any previous Japanese warplane - yet poor heat-treatment of high-strength steel had the consequence that the landing gears often snapped. Progressive deterioration in quality control meant that pilots never knew how individual aircraft would perform, whether the brakes would work, and even whether - in attampting to intercept B-29 Superfortresses over Japan - they would be able to climb high enough.

Despite these problems the Hayate was essentially a superb fighter - a captured Ki-84-1a was to outclimb and outmanoeuvre a P-47 Thunderbolt, and a P-51.

The first batches were sent to China, where the 22nd. Sentai, when equipped with the new fighter, were able to fly rings  around Chennault's 14th. Air Force.

The 22nd. Sentai was later moved to the Philippines, where problems overtook them, with many accidents and shortages and extremely poor serviceability.

Frequent bombing of the Musashi engine factory, and the desperate need to conserve raw materials (the shortages resulting primarily from the American submarine blockade) led to various projects and prototypes made of wood or steel.

Total production of the Ki-84 reached 3,514.


Nakajima Hikoki KK  Also built by Mansyu Hikoki Seizo KK and (3 Ki-106) Tachikawa Hikoki KK

Single-seat interceptor and fighter-bomber

Span: 36' 11" (11.238 metres)Length: 32' 7" (9.92 metres)Height: 11' 1" (3.385 metres)

In all production models - One 1,900 hp Nakajima Homare Ha-45 Model 11 18-cylinder two-row radial

2 x 20mm Ho-5 cannon in wings, each with 150 rounds
2 x 12.7mm Type 103 machine-guns in upper fuselage, each with 350 rounds
4 x 20mm Ho-5 cannon (2 in wings, 2 in fuselage) each with 150 rounds
2 x 30 mm Ho-105 cannon in wings,  2 x 20 mm Ho-5 cannon in fuselage
(all models)
Two racks under outer wings for bombs or fuel tanks up to 250 kg (550 lbs) each

Maximum speed 388 mph (624 km/hour) /  Initial climb (typical) 3.600 feet (1,100 metres) per minute
Service ceiling 34,450 (10,500 metres)
Range on internal fuel 1,025 miles (1,650 kilometres)
Range with 98-gallon drop tanks 1,815 miles (2,920 kilometres)

Kawasaki Ki-61 Hien 'Tony' - Japanese Army fighter

Grumman F6F Hellcat - US shipborne fighter

Aircraft of the Pacific War - Index

The Battle of the Philippine Sea,  19-20 June 1944

The Battle for Leyte Gulf,  23-26 October 1944

D James' Naval & Maritime Pages

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 The main source for the above text was Bill Gunston's
"Combat Aircraft of World War II" (Salamander, London 1978).
The data and the drawing of the Ki-84 are reproduced with thanks from the same source.