Sometimes called the “Army Zero” by American pilots, and overshadowed by its Navy rival, the Mitsubishi A6M “Zero”, the “Hayabusa” was the most common (and deadly) adversary for the Allied pilots during the Malayan campaign. Pilots flying the Ki-43 shot down more Allied aircraft than in any other Japanese fighter. And almost all the JAAF’S aces achieved most of their kills in it.
The Nakajima Ki-43 Hayabusa (隼, “Peregrine Falcon”, Army designation “Army Type 1 Fighter” 一式戦闘機) originated in a Japanese Imperial Army specification, issued to Nakajima Hikoki K. K. in December 1937 for a replacement of the nimble Nakajima Ki-27. They wanted more speed (501 km/h or 311 mph), better time to climb (5,000 m or 16,405 ft in 5 minutes), and a range of 1,288 km (800 mi). The specified armament comprised two 7.7 mm machine guns and the new airplane had to maneuver as well as the Ki-27.
The birth of the Hayabusa was not easy. Nakajima’s chief designer Hideo Itokawa and his team delivered the first prototype of the Ki-43 on December 12, 1938. After its maiden flight in January 1939 and subsequent tests, the Japanese Army pilots reported that it was unresponsive to control, stiff, slow and too heavy. The cockpit canopy was awkward and the landing gear difficult to use. Two prototypes followed in February and March 1939, but as there were no significant improvements, the Army rejected the Ki-43.
For a time, it seemed that Nakajima would abandon the Ki-43. However, the firm decided to salvage their investment and began work on the first of a series of ten development aircraft. The series of changes introduced during this process saw the Ki-43 turn into an excellent design.
Apart from the Ha-105 radial engine, two 12.7mm machine guns and a treated duralumin outer skin, the most important innovation was the introduction of ‘butterfly’ flaps. When the pilot deployed these tapered flaps at speed, they helped to pitch the airplane’s nose up without generating too much drag, and the turning circle of the Ki-43 shrank dramatically. The next round of evaluation left the test pilots highly impressed and the army ordered the Ki-43-I into production as Army Type 1 Fighter with a Nakajima Ha-25 engine and to be armed with two 7.7mm machine guns.
The first unit equipped with the Ki 43-I was the 59th Sentai at Hankow Airfield, during June–August 1941, flying operational sorties over Hengyang on October 29, 1941.The second unit to re-equip with the new Aircraft was the 64th Sentai, from August to November 1941.
The Ki-43 initially enjoyed air superiority in the skies of Malaya, Netherlands East Indies, Burma and New Guinea. This was partly due to the better performance of the Oscar, partly because of the Japanese pilot’s battle experience and partly due to the relatively small numbers of combat-ready Allied fighters.
In combat, the Hayabusa was superior to any opposing fighter it encountered in the early part of the war. Like the Zero, the Hayabusa turned and stalled better than most fighters to see combat in the war. Low gross weight was an important factor in this performance. Nakajima achieved it by building a spare, tidy airframe powered by a relatively small engine, no pilot armor and no self-sealing fuel tanks.
These sacrifices would cost dearly when the Allies began to field airplanes with heavy firepower. Despite these drawbacks, the Hayabusa remained formidable, even as more experienced Allied pilots and better aircraft entered the fray. The type was well liked in the JAAF because of its pleasant flight characteristics and excellent maneuverability. Almost all JAAF fighter aces claimed victories with Hayabusa in some part of their career.
At the end of the war, most Hayabusa units received Ki-84 Hayate “Frank” fighters, but some units flew the Hayabusa to the end of the war. And a large percentage of Ki.43’s was used as Kamikazes during the final months of the conflict.
The Ki-43 was the most widely used Army fighter, and equipped 30 Sentai and 12 Chutai (independent squadrons). The aircraft would be produced at three factories. Nakajima produced the most aircraft, completed 3,239. The Army’s First Army Air Arsenal (Tachikawa Dai-Ichi Rikugun Kokusho) was the least successful, producing 49 aircraft between October 1942 and November 1943. Finally the Tachikawa Hikoko K.K. (Tachikawa Aircraft Company) produced the bulk of the later aircraft, completing 2,629 aircraft between May 1943 and the end of the war.
After the war, the French Air Force in Indochina equipped two squadrons with captured / abandoned Ki.43’s and used them in their offensives against Viet Minh rebels. And in the Netherlands East Indies, the newly declared Indonesian government took over some abandoned Ki.43’s and used them during their fight against Dutch forces.
The top-scoring Hayabusa pilot was Sergeant Satoshi Anabuki with 39 confirmed victories, almost all scored with the Ki-43. Another remarkable Hayabusa pilot was Lt. Col. Tateo Kato, CO of the 64th Sentai. Popularly hailed as the “War God,”
Kato was the most celebrated pilot of the Imperial Japanese Army Air Force in World War II. His career as a fighter pilot peaked during the Sino – Japanese war when, flying a Kawasaki Ki 10 biplane, he downed four Polikarpov I-15s on March 25, 1938. His squadron converted to Nakajima Ki.27’s and by May 1938, Kato’s unit had claimed 39 enemy craft for a loss of only three Ki 27s—with Kato himself claiming four more kills. He then rotated back to Japan with a final tally of nine, which made him the leading ace of the war.
During the summer of 1941 Kato was appointed commanding officer of the 64th Sentai, then re-equipping with Ki.43’s. The Sentai began the war by escorting naval vessels to Malaysia in preparation for the conquest of Malaya and Singapore. Over the next few weeks the 64th Sentai skirmished repeatedly with Brewster Buffalos (and later Hawker Hurricanes) and achieved air superiority. The 64th Sentai was hurriedly sent to Bangkok, Thailand, to reinforce the 77th Sentai (flying Ki.27’s) , On December 23, 1941, they escorted several heavy bomber formations on a large raid over Rangoon—where they ran straight into the P-40’s of the AVG or Flying Tigers. The American pilots later claimed 16 bombers and two Ki 43 fighters in exchange for four British and two American fighters.
The 64th Sentai transferred back to Malaya and the East Indies where Kato’s men eliminated British and Dutch aircraft from Sumatra and Java during January and February 1942. Kato was promoted to Lieutenant Colonel in March, and his aerial exploits caused such public adoration that Kato became hailed as the “War God”, a singularly unusual tribute in Japanese culture. Kato himself was a fearless, charismatic individual, unique among officers of his grade for accompanying his men into combat. Without exception, he always led by example and was highly prized by squadron mates.
During March and April 1942, the 64th continued to battle in Burma, notably against the P-40’s of the AVG. The end of Kato’s career came on May 22, when Kato in company with two other Hayabusas went after a lone RAF Bristol Blenheim that had dropped some bombs on Akyab airfield. As Kato pulled up from his raking pass, the British tail gunner shot him down in flames.
The Japanese people perpetuated his memory through the song “Kato Hayabusa Sentoki Tai” (Kato’s Fighter Air Group). At the time of his passing, Kato was credited with 18 kills. The “War God” was also posthumously elevated two grades to major general, a standard Japanese practice. More important, the lessons he taught the 64th Sentai allowed it to continue fighting successfully without him. It would emerge as the most famous Japanese army air force unit of World War II.
Another unique fact is that, in 1944, a movie was made to honor him. The black and white movie is called Kato Hayabusa Sento-Tai (加藤隼戦闘隊) or ‘Colonel Kato’s Hayabusa Squadron’ and is available on U-Tube. Here’s the link: