It entered combat with the 22nd Sentai at Hankow, China in August 1944, where it proved costly to the U.S. 14th Air Force, and the 23rd Fighter Group in particular. Even with the Americans now equipped with the P-51B and P-51D Mustang instead of their older P-40s, pilot quality was the deciding factor in a combat. While aces like Charles Older, Deputy Commander of the 23rd Fighter Group could score impressively, such as when he shot down four Ki.84s at low altitude in a surprise strike at Hankow that September - this was a one-time only event when he managed to surprise the four fighters shortly after takeoff, catching them at a disadvantage. Older related to this writer in an interview in 2002 that he considered the Ki.84 to be the best Japanese fighter of the war, and the most dangerous opponent he flew against. Other American pilots learned this to their cost, as the Japanese Army Air Force regained a lost advantage during the Japanese Army’s final China offensive in the Fall of 1944.

http://www.j-aircraft.com/faq/ki84_p...ormance%20data

There are a few differing views on Franks speed covered here.


I have a copy of a translation of a captured document (hand written notes) of unknown reliability which indicates two maximum speeds for the Ki 84-1 (Light) and Ki 84-1 (Improved). The two speeds apparently relate to the Ha 45 rating of 2000 hp at 1500 meters and 1800hp at 6000 meters.

Ki 84-1 (Light) 664 kph (=412 mph) and 693 kph (=430 mph)

Ki 84-1 (Improved) 658 kph (=409 mph) and 688 kph (=427 mph).

Fully equiped wgt of Light = 3576 kg; Improved = 3858 kg


During the war TAIC rated Ki 84's max speed at 422 mph.

There are many instances when Japanese "official" figures are less than US tests and observed combat performance.