Nakajima Ki-84

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The Nakajima Ki-84 Hayate (疾風, "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 Army designation was "Type 4 Fighter" (四式戦闘機).

The Ki-84 first flew in March 1943. While the design was solid a shortage of fuel and construction materials, poor production quality, and lack of skilled pilots kept it from reaching its potential. After the war a captured example was tested by the U.S. Army using high-octane fuel and achieved a speed of 689 km/h. A total of 3,449 were produced.

The Ki-84 was the only army fighter with a four-bladed propeller; this was chosen to reduce the diameter and provide ground clearance. Several interesting experimental variants of the Ki-84 were produced: the wooden Ki-103, the steel (rather than duralumin) Ki-113, and the Ki-116, with the Nakajima Ha-45 engine replaced by a Mitsubishi Ha-112-II.

Service history

The Ki-84 was designed to replace the Ki-43 and Ki-44. It participed in combat for the first time from the base in Hankow during 1944, equipped 10 sentais in the Philippines, and served in Southeast Asia, Taiwan, and Okinawa, as well as local defense of Japan. It could out-turn a Spitfire, and out-run and out-climb a P-51H at 20,000 ft (6,000 m). After World War II it was used by the Chinese Communist Air Force until the 1950s.

Versions

Ki-84 (prototype)
Ki-84 (evaluation model)
Ki-84 (pre-production model)
Ki-84 Ia Hayate fighter Type 4 of Army (Mark Ia)
Ki-84 Ib (Mark Ib) -four cannons Ho-5 of 20 mm
Ki-84 Ic (Mark Ic) -Version against Bombers,with two cannons Ho-5 of 20 mm and Ho-105 of 30 mm in wings
Ki-84 Ia(Manshu Type) -Manufactured in Manchukuo for Mansyu by Nakajima License.
Ki-84 II (Army designation Ki-84 Ia,Ib,Ic) -similar to models mentioned above
Ki-84 N/P/R -high altitude versions
Ki-106 -Prototypes in total wood construction
Ki-113 -Prototype similar at Ki-84 Ib in Steel
Ki-116 -evaluation model, equipped with Mitsubishi 62(Ha-33), 1,500 hp (1,120 kW)
Ki-117 -Redesigning of Ki-84 N.

Specifications (Ki-84-Ia)

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 a Browning design and therefore if it lost perhaps 27% of its 900 rpm firing rate each when synchronized with the prop, it would be 657 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

Total production: 3,514 examples
*3,288 by Nakajima
*94 by Mansyu

External links