The Kawasaki Ki-100 was a fighter-interceptor aircraft used by the Imperial Japanese Army in World War II. The Japanese Army designation was "Type 5 Fighter".

The German licensed engine DB.601a produced in Japan under the brand name Ha.40 ("Hatsudoki" - in Japanese engine) unfortunately turned out to be unreliable. The level of technology at Japanese factories turned out to be significantly lower and the Japanese could not solve the problems with the limiting thermal conditions of this motor.

The question arose of which engine to put on the Ki-61 airframes produced in large quantities, which turned out to be without engines. It was decided to adapt the Mitsubishi Ha.112 engine for this purpose. These motors were used on Ki.102 high-altitude fighters, KI.46 reconnaissance aircraft and some other aircraft.

After the American aviation on January 19, 1945, bombed an engine plant in the city of Akashi, where engines for the Ki-61 were produced, the issue of replacing the engine was resolved automatically.

In early December 1944, work began on installing a new engine on three Ki.61 non-motorized airframes. And just seven weeks later, on February 1, 1945, the first Ki.100 took off. In the course of successful tests, the new fighter showed even better performance than expected.

The maximum speed of the Ki.100-1-Ko has dropped by 10-20 km / h compared to the latest model Ki.61 at all altitudes, but the maneuverability and climb rate have improved significantly due to the reduction in weight and the increase in power density. Better steel and takeoff and landing characteristics. At the Yokot airbase, training battles were conducted with the captured P-51C "Mustang", which showed the superiority of the Ki.100-I-Ko in maneuverability. Better than the Mustang, the Ki.100 was also on a dive, but the superiority in speed allowed the Mustang to withdraw from the battle at any moment. With regard to the F6F Hellcat, it was assumed that the Ki.100 was superior in all respects, but no joint trials were carried out - there was no trophy Hellcat in flightable condition.

Apart from replacing the motor and related alterations, no significant changes were made to the design. The fuel supply remained the same, the armament and ammunition also did not change, and the Sumitomo propeller, manufactured under license from Hamilton, was also preserved.

According to the test results in February, the fourth Ki-61-II airframe was also redesigned, which became the prototype of the production aircraft, which received the designation "Type 5 Model 1A Army Fighter" (Ki-100-1a). On his model, 271 ready-made gliders, waiting for their engines at the Kagamigahara plant, were modified. By the end of June, all non-powered gliders received Ha.112 motors.

Variants

Note: Ko, Otsu, Hei and Tei are the Japanese equivalents to a, b, c, d. Kai ('modified' or 'improved') was also used for some models of the Ki-61.

• Ki-100. (prototypes): one batch of Kawasaki Ki-61 II KAI with radial engine. 3 built as such.
• Ki-100 I-Ko. Fighter Type 5 of Army (Mark Ia) initial model of series, KI-61 II KAI modified. 271 built as such.
• Ki-100 I-Otsu. (Mark Ib) full-vision canopy. 118 built as such.
• Ki-100 II. Engine Mitsubishi Ha-112-II Ru with turbocharger, 1,120 kW (1,500 hp). 3 built as such.

Total production: 395 examples.

The army units that were supposed to receive the Ki-100 included the following Sentai: 5th, 17th, 18th, 20th, 59th, 111th, 112th, 200th and the 244th and 81st separate fighter companies. Along with the previously named Air Force units, the pilots received training at the army flight schools Akeno and Hitachi (Mito). Many of the instructors of the Akeno and Hitachi schools, often seconded from the operational units, also flew out on combat missions.

The Ki-100 flew its first combat sortie on the night of March 9, 1945, and suffered its first defeat on April 7, 1945, when the Ki-100, piloted by Senior Sergeant Yasuo Hiema from 18 Sentai, was shot down by B-29 ... The senior sergeant's last words were: "Attack formations over and over again." Allied crews soon realized that they were facing a formidable new fighter, although encounters with the Ki-100 were much less frequent than with the Ki-84. However, during the interception of the B-29 at high altitudes, the new Japanese fighters became similar to the Ha-112-II due to a drop in engine power. Most of the B-29s' raids were soon carried out at low altitudes, followed by incendiary raids on cities in Japan. The most effective way to attack superfortresses was head-on attacks. When approaching the bombers, the Japanese pilot had to constantly change the trajectory of the approach, refusing this technique was mortally dangerous due to the concentration of defensive fire from the bombers. In this type of warfare, the Mitsubishi J2M Raiden naval fighter was rated as the preferred choice.

Most of the Type 5 fighters produced - about 150 pieces were delivered to 111 Sentai, almost half of which were soon lost due to the inexperience of the pilots.

During March and April 1945, experienced instructors from the Akeno Army Flight School conducted comprehensive comparison flights of the Ki-100 fighter with the Ki-84, which was considered the best fighter in the JAAF. Their conclusions were that in the presence of two pilots of equal experience, the Ki-100 will always win in battle. From mid-April, Major Yasuhiko Kuroe, an experienced combat veteran, was recruited into the Flying Circus of captured Allied aircraft, including a Mustang captured in China. This "circus" traveled to various operational fighter bases throughout Japan, training pilots in the most effective ways to combat enemy aircraft.

On July 25, 1945, 18 Ki-100 fighters from the 244th Sentai collided with ten Hellcats from 31 (VF-31) squadrons from the aircraft carrier Belleau Wood in an aerial battle where Ki-100 pilots claimed to have won 12 victories with their losses of two planes. Mutual claims about the "true" outcome of this fight still arise around these events. The American side claims to have lost two Hellcats and shot down two Ki-100s, including the Ki-100 Tsutae Obara and the Hellcat Ensign Edwin White collided in combat, killing both pilots.

The last loss of the Ki-100 occurred on August 14, 1945, the day before Japan's surrender, when Sergeant Major Fumihiko Tamagake of 244th Sentai was shot down by a Mustang.

The overall assessment of the Ki-100's combat effectiveness is quite high. In the hands of an experienced pilot, the Ki-100 could outwit any American fighter, including the formidable P-51D Mustang and P-47N, which accompanied the B-29 on raids over Japan. The Ki-100 was comparable in speed, especially at medium altitudes, and together with the Ki-84 and Kawanishi N1K-J armies, it was a formidable foe.

Photo	Description
	Drawing Ki 100-I
	Drawing Ki 100-II
	Ki-100-II with damaged elevator

Bibliography

• "Japanese Aircraft of the Pacific War" /Francillon, Rene J./
• "Warplanes of the Second World War" /Green, William/