Ki-84/Homare in the U.S.

Discussion in 'Flight Test Data' started by Sgt. Pappy, Apr 12, 2008.

  1. Sgt. Pappy

    Sgt. Pappy Member

    Jun 7, 2006
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    I think it's been brought up before but I was thinking this section may provide better results.

    The Ki-84 was tested in the U.S. and there are random figures floating around which stated figures of 427 mph in level flight. This is likely calculated data since it happened before the end of the war.

    I'd like to know if the U.S. changed the engine in any way, manner or form in order to test it. After all, the Homare's were unreliable during the war. Perhaps they could not run the U.S. 100/130 octane grade without some modification.

  2. wells

    wells Member

    Mar 9, 2008
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    In the original TAIC manual from Dec.44, the performance was estimated at 422 mph. This was based on the assumption that the lines were similar to OSCAR. Then, in the March 1945 TAIC supplement, the performance was updated to the 427 mph figure. By that time, they had found some aircraft along with some documentation. The aircraft were not flown in the Philippines until the summer, however, so these performance figures are NOT based on any flight test that the US made, but most likely originated from captured japanese documents. To quote Richard Dunn,

    There was a trial against a Seafire III in which stated,

    In that trial, power was limited to +250mm boost and 2900 RPM, because the engine had only been run for 8 hours.

    Note, that is the rated power for the Model 12 engine. The Model 21 engine was rated at +350 mm and 3000 RPM ( +500 mm with methanol injection ).

    In that trial, the constant speed unit failed at airspeeds of 230 kias at 5000 ft, 205 kias at 15000 ft, 218 kias at 20000 ft. So, maximum speeds were not reached.

    After the war, at least 2 examples were restored in the USA ( T2-301 and T2-302 ) at the Middletown Air Depot ( where it was repainted ). At least one of those was test flown at Wright Field. An article in the January, 1976 issue of Air International gives some details of these tests.

    According to Richard Dunn ( )

    These are the exact same figures that appear in the TAIC documents, before any examples had been flown, so it is unlikely that any performance testing was done at Wright Field. Further evidence is given in the Air International Article where the evaluation states,

    Finally, another quote from Richard Dunn,

    That's the extent of my research so far. Some conclusions can be drawn however

    With the Homare 21 engine, maximum speed is higher than 624 kph, but only estimates of the extent of such performance has so far been found.

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