Ki-84 1a Performance

[billswagger]

There seems to be some fuzzy history surrounding this plane. I know that the USAAF has the opportunity to test the plane in flight under nominal conditions using a high grade fuel and was able to achieve a high speed of 426mph.

I just wonder how much of a difference the fuel made in performance, It is well known that by late war standards the Japanese did not have the best gasoline for their aircraft which hindered a lot of their performance, but i would like to see more performance stats on this plane particularly related to the combat era, and not a post war mock up.

So far much of the information suggests that it was much slower than what was achieved by USAAF tests, but i would like to see if any more information could be gathered on this great plane to get a better depiction of how it may have actually peformed during the war.

May have it been faster than the F4U?



Bill

 

[windswords]

Bill,

FWIW I have an old Aero Profile booklet on the Ki-84 written by Francillion. In it he states that the prototypes achieved 388 MPH. By the time the first production models came out they had individual exhaust stacks on the Homare radial which increased the speed 8 or 9 MPH. That would bring the speed up to 396-97 MPH. According to the tables at the end of the booklet the plane tested in America was a few hundred pounds lighter (no armmament?) than the Japanese prototype. The engine was a later model of the Homare and was run at a higher RPM setting. That along with the superior AV gas and it seems plausible that a speed of 426-27 is possible.

Under combat conditions the lack of good gas, poor build quality due to the bombing of the Japanese islands, and other factors ment that the actual performance was not consistent from plane to plane. Some performed well and others did not.

You may want to head over to J-aircraft.com. They had a big discussion about this some time ago. It might still be there. I have been thinking of opening this subject up again over there to discuss the data in my Francillion booklet.

 

[cherry blossom]

Some discussions are saved at Performance of Ha-45-23 engined Ki-84 Hayates and Nakajima Ki-84 performance : various views | Facebook. What is clear is that the Ki-84 performance in combat was limited by Japan's 1945 problems rather than by the designers work.

 

[renrich]

The F4U4 had a vmax of around 445 mph at critical altitude so it seems doubtful that the KI84 even with good fuel could equal that.

 

[Vincenzo]

the engien was not built for high grade fuel so this not give improvement, the american manual for the ki 84 explicite that the need use the right octane fuel no a high grade common for us fighters, see in other thread in j-aircraft.org

 

[billswagger]

thanks for the responses.

I've looked through j-aircraft a bit and wasn't able to turn up much on the ki-84 for performance and fuel grade. If you have a direct link to the ariticle that would be appreciated. I can't rely on a post from another forum as a source but it would be great to see what information they have, perhaps an article or chart or something from the period that describes the performance.

There were some other sources that also seem to indicate a variety of numbers based on fuel grade, This is repeated in several internet articles but nothing mentions specific performance other than 388 top speed.

I'm still searching for more information, but it seems that actual documentation is very limited or non-existant. Much of the information available appears to be second hand.



Bill

 

[Vincenzo]

some usefull threads on Type 4 in j-aircraft
Ki-84 report...USAAF test...
Army Type 4 Fighter (Ki-84) pilot protection
Ki-84-Ib - *Production, Serial Number Policy, and designations*

other what already linked to cherry