NAKA JIMA KI84 IA HAYATE (FRANK) Japanese Army Type 4 Fighter KI84 IA HAYATE (FRANK) About the HAYATE In April 1944, the Ki-84 was formally adopted as the Type 4 fighter "Hayate" (Hayate), and by the end of the war, approximately 3,500 were produced by Nakajima Aircraft Company. Equipped with a 2,000 hp Hur 45 engine, the Ki-84 had the highest speed of any mass-produced Japanese fighter aircraft at 624 km/h (624 mph) and was heavily armed with two 20 mm machine guns and two 12.7 mm aircraft. It was the centerpiece of the Japanese Army's air force during the Battle of Leyte Island in the Philippines, the Battle of Okinawa, the Battle of Manchuria, and the air defense of the Japanese mainland, and fought well against the P51 Mustang and F6F Hellcat.