THE 456th FIGHTER INTERCEPTOR SQUADRON

THE PROTECTORS OF  S. A. C.

 

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The Nakajima Ki-84 "Frank"

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"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.

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The Nakajima Ki-84 Hayate ("Gale") was a single-seat fighter used by the Japanese Imperial Army in World War II. It was the last in Nakajima's line of classic fighters and considered one of the best-performing craft from any country. The Allied codename was "Frank"; the Japanese Army designation was, "Type 4 Fighter"

 

Design And Development

Design of the Ki-84 commenced in early 1942 to meet a Imperial Japanese Army Air Service requirement for a replacement for the Ki-43 "Hayabusa" ("peregrine falcon") fighter, which had just entered service. The specification recognized the need to combine the maneuverability of the Ki-43 (see below) with performance to match the best western fighters and heavy firepower . The Ki-84 first flew in March 1943  Although the design itself was solid, the shortage of fuel and construction materials, poor production quality, and lack of skilled pilots prevented the fighter from reaching its potential. A total of 3,514 were produced.

The Ki-84 addressed two of the most common complaints about Nakajima's previous Japanese Imperial Army fighter, the popular and highly maneuverable Ki-43 "Hayabusa" ("peregrine falcon"): it tackled issues of insufficient firepower, poor defensive armor and a lack of climbing power. The Ki-84 was introduced with two 12.7mm (50-caliber) machine guns and two 20mm cannons, a considerable improvement over the single 7.7mm and single 12.7mm machine guns which equipped the Hayabusa. Defensive armor offered Hayate pilots better protection than the unsealed wing tanks and light-alloy airframe of the Ki-43. In addition, the Ki-84 used a 65mm armor-glass canopy, 13mm of head and back armor, and multiple bulkheads in the fuselage, which protected both the methanol-water tank (used to increase the effectiveness of the supercharger) and also the centrally located fuel tank.

But it was the powerplant that gave the Hayate its high speed and prowess in combat. Derived from the Homare engine common to many Japanese aircraft, the Hayate used a direct-injection version of the engine, using water injection to aid the supercharger in giving the Ki-84 a rated 2000 hp at takeoff. This combination—in theory, at least—gave it a climb rate and top speed roughly competitive with the top Allied fighters of the late Pacific theater, the P-51D Mustang and P-47D Thunderbolt (with top speeds of 433 and 426 mph, respectively). The Hayate's initial testing at Tachikawa in early summer 1943 saw test pilot Lt. Funabashi reach a maximum level speed of 634 km/h (394 mph) in the second prototype, but after the war a captured example was tested by the U.S. Army using high-octane fuel and achieved a speed of 690 km/h (430 mph).

The complicated direct-injection engine, however, required a great deal of care in construction and maintenance and, as the Allies advanced toward the Japanese homeland, it became increasingly difficult to support the Hayate's designed performance. Compounding reliability issues was the Allied submarine blockade which prevented delivery of crucial components such as the landing gear. Many Hayates consequently suffered strut collapses on landing.

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Ki-43 "Hayabusa" ("peregrine falcon")
Кi-43 Hayabusa was the advanced fighter of the Japanese army aircraft in the beginning of the World War II. This airplane became very serious opponent for air force of allies and was one of the most mass airplanes of army air forces.
The basic modifications of the machine were Кi-43-I (three versions) with the 980 hp engine Ha - 25 and a two-blade propeller, Ki-43-II (three versions) with more high-power engine and a three-blade propeller and Ki-43-III with 1230 hp engine Ha-115-II.
Manufacture of these fighters has made more than 5900 aircrafts and proceeded up to the end of WW II when Ki-43 it is already obsolete of its armament and protection. Кi-43 Hayabusa was the advanced fighter of the Japanese army aircraft in the beginning of the World War II. This airplane became very serious opponent for air force of allies and was one of the most mass airplanes of army air forces.
The basic modifications of the machine were Кi-43-I (three versions) with the 980 hp engine Ha - 25 and a two-blade propeller, Ki-43-II (three versions) with more high-power engine and a three-blade propeller and Ki-43-III with 1230 hp engine Ha-115-II.
Manufacture of these fighters has made more than 5900 aircrafts and proceeded up to the end of WW II when Ki-43 it is already obsolete of its armament and protection.

General characteristics

Performance

Armament

The Ho-5 cannon in the wings had 150 rpg. Projectiles weighed 112 g AP, and 79 g HE (HE=12%). The 20X94 cartridge had muzzle velocity of 820 m/s formerly, but was reduced to 700 m/s for AP and 730 m/s for HE due to alloy shortages in the guns. It still had a range of 900 m. Rate of fire was 850 rpm each. The twin Type 1 (Ho-103) 12.7 mm machine guns were based on the Browning M2 design; however, they lost 50%+ of its 900 rpm cyclic rate when synchronized with the prop; consequently, their cyclic rate was but 400 rpm. Each carried 350 rounds of ammo in the cowl. The AP bullets were 35.4 g and the HE were 33 g (HE=2.3%) - Italian, together with 38 g HE - Japanese made. The 12.7x81 cartridge gave a muzzle velocity of 760 m/s for the AP, and 770-796 m/s for the HE and an effective firing range of 750 m. It was an unreliable gun earlier in the war. Sensitive rudder made it a poor gun platform at first.

Production

 

 

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Last Updated

04/26/2009

 

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