That part about these document belongs to the Ki-83 website and is from http://www.j-aircraft.com/ so i don't know anything about it (unfortunatly)!Huck wrote:
What kind of documents? I would love to see some speed tests? Can you scan them?
As for Ki-83, with a good high altitude engine, I have no doubts that it could have been brought up to 450-460 mph range. But the Japanese never had good high altitude engines, nor reliable high power engines. There was intensive work done in the last months of war to replace the powerful 18 cyl radial of Ki-84 with the reliable but less powerful 14 cyl radial of Ki-100.
BTW That Ki-84 with Ha-112-II engine is a Ki-116 (only one was made from an existing Ki-84 airframe. This engine was substantially lighter than the HA-45 that it replaced, and required that the engine mounts be lengthened in order to maintain the center of gravity. In order to compensate for the additional length, the tail surfaces had to be enlarged)
http://www.csd.uwo.ca/~pettypi/elevon/b ... ki-84.html
This comes from another post from another long time ago forum wich also originated from (i guess) http://www.j-aircraft.com/
The Japanese "official" maximum speed (624 kph) isn't really the Type 4 fighter's maximum speed comparable to max speeds published for Allied fighters. It was obtained at 2900 rpm and +150 boost. In this condition the Type 4 fighter could operate for an extended period and is more like a high speed cruise. At 3000 rpm and +200 boost the "max" speed was 650 kph or over 400 mph and this was far from the limit for the Type 4 fighter. We know this not only from captured techinical documents but from POWs. The US tests figures are quite close to the actual "real" max speed obtained by the Japanese.
The question about fuel implies that US (presumably 100 Octane) fuel would have made the Type 4 fighter faster. The Japanese got their performance (equal to that in US tests) using 92 octane fuel and methanol injection. The methanol injection plus type 92 fuel gave the desired anti-knock performance. There was no need to use 100 octane fuel.
Also hidden in the question is the myth that the Japanese did not have 100 octane fuel. They had it and used in captured aircraft that were optimized for its use and sometimes used in Japanese aircraft. The Japanese not only did octane additive research in the Homeland but captured refineries in the NEI capable of producing 1000s of tons of additives per month. In fact some type 92 fuel was produced as natural tops and some produced from lower grade fuels with additives. In addition to type 92 fuel the Japanese sometimes used type 95 fuel in the Type 4 fighter.
I have some information on the history of the plane:
There were two Ki-84s captured at Utsunomiya South military airfield at the close of the war. These planes were serial numbered 2366 and 3060 and were shipped on board USS Barnes from Yokosuka to USA on 3 November 1945. They were handed over to the USAAF on 7 December 1945. Once in the US, the Office of Air Force Intelligence gave each a Foreign Evaluation (FE) number. One became FE-301, the other became FE-302.
FE-302 was "restored" at Middletown Air Depot in Pennsylvania. On 16 March 1946 is was flown for the first time after being delivered to the US. On 20 May 1946 it was delivered to Patterson Field, then flown to Wright Field on 27 May 1946. On 3 July 1946 it was flown to Park Ridge to be included in an air museum.
During its flights at Middletown, it was compared to the P-51 and P-47. It compared "favorably." It was criticized for its lack of armor. There were frequent failures of the exhaust stacks due to the use of poor materials. It was further criticized for showing poor welding techniques and poor suspension design.
The plane was scrapped when Park Ridge was reactivated during the Korean War.
Source: War Prizes Phil Butler, Midland Counties Publications, page 240