Author Topic: Ki-84 U.S. testing (Read 5479 times)

SgtPappy · « **on:** January 13, 2008, 09:20:19 PM »

I've been looking all over the BBS, google and the IL-2 BBS just in case someone already posted this already.

The Ki-84 (allegedly) found figures like 427 mph when tested in the US in 1946.
- What were the criteria of the tests? 100/130 grade octane or was it 115/145
grade?
- The paint was stripped and the guns were taken off ...
- Was there a special injection?

angelsandair · « **Reply #1 on:** January 13, 2008, 10:30:14 PM »

The Ki-84 addressed two of the most common complaints about Nakajima's previous Japanese Imperial Army fighter, the popular and highly maneuverable Ki-43 "Hayabusa" ("peregrine falcon"): it tackled issues of insufficient firepower, poor defensive armor and a lack of climbing power. The Ki-84 was introduced with two 12.7mm (50-caliber) machine guns and two 20mm cannons, a considerable improvement over the single 7.7mm and single 12.7mm machine guns which equipped the Hayabusa. Defensive armor offered Hayate pilots better protection than the unsealed wing tanks and light-alloy airframe of the Ki-43. In addition, the Ki-84 used a 65mm armor-glass canopy, 13mm of head and back armor, and multiple bulkheads in the fuselage, which protected both the methanol-water tank (used to increase the effectiveness of the supercharger) and also the centrally located fuel tank.

But it was the powerplant that gave the Hayate its high speed and prowess in combat. Derived from the Homare engine common to many Japanese aircraft, the Hayate used a direct-injection version of the engine, using water injection to aid the supercharger in giving the Ki-84 a rated 2000 hp at takeoff. This combination—in theory, at least—gave it a climb rate and top speed roughly competitive with the top Allied fighters of the late Pacific theater, the P-51D Mustang and P-47D Thunderbolt (with top speeds of 433 and 426 mph, respectively). The Hayate's initial testing at Tachikawa in early summer 1943 saw test pilot Lt. Funabashi reach a maximum level speed of 634 km/h (394 mph) in the second prototype, but after the war a captured example was tested by the U.S. Army using high-octane fuel and achieved a speed of 690 km/h (430 mph).

The complicated direct-injection engine, however, required a great deal of care in construction and maintenance and, as the Allies advanced toward the Japanese homeland, it became increasingly difficult to support the Hayate's designed performance. Compounding reliability issues was the Allied submarine blockade which prevented delivery of crucial components such as the landing gear. Many Hayates consequently suffered strut collapses on landing.
i got it off of here www.answers.com/topic/nakajima-ki-84 (i hope i did it right)

Saxman · « **Reply #2 on:** January 13, 2008, 10:50:11 PM »

It should also be noted that the poor quality of the fuel available prevented the Ki-84 from achieving its on-paper performance in the field.

TequilaChaser · « **Reply #3 on:** January 14, 2008, 12:21:32 AM »

also you need to make sure you comparing the right series of Ki-84

the one in Aces High is the Ki-84-la, not the later versions which are a bit faster and also have better armament......

Karnak · « **Reply #4 on:** January 14, 2008, 12:02:41 PM »

Quote

Originally posted by TequilaChaser
also you need to make sure you comparing the right series of Ki-84

the one in Aces High is the Ki-84-la, not the later versions which are a bit faster and also have better armament......

Nope. The Ha-45-21 which provided the highest peak power can be found on Ki-84-Ia fighters as well. The engine varried, but it is not tracked by model number.

SgtPappy · « **Reply #5 on:** January 14, 2008, 03:06:44 PM »

Thanks guys

lol, Angelsandair, the link didn't work

yea, I noticed the Japanese weren't able to manufacture synthetic fuels anywhere near as well as countries like the U.S. and Germany could; thus they couldn't find the best performance in their engines.

I'm just trying to find what octane level was used during the U.S. testing of the Hayate... was it 100/130 or 115/145?

angelsandair · « **Reply #6 on:** January 14, 2008, 08:16:38 PM »

well just copy the link

SgtPappy · « **Reply #7 on:** January 14, 2008, 09:13:33 PM »

Yea, that did the trick. I saw that page too, it's good, but too bad it doesn't specify fuel grade.

angelsandair · « **Reply #8 on:** January 14, 2008, 10:26:16 PM »

ehhh, its what u get for googling information, but it had some interesting information about other japanese planes like the ki-43, ki-44, ki-83..........

angelsandair · « **Reply #9 on:** January 14, 2008, 10:30:38 PM »

www.indianamilitary.org/.../AirPower%20Jan75.htm hey, i found a HUGE page on japanese fighters, just kind of scanned it over, man u will love it okay, ur just gonna have to type in indianamilitary.org, its not working even if u copy and paste

Widewing · « **Reply #10 on:** January 14, 2008, 11:57:51 PM »

Quote

Originally posted by angelsandair
www.indianamilitary.org/.../AirPower%20Jan75.htm hey, i found a HUGE page on japanese fighters, just kind of scanned it over, man u will love it okay, ur just gonna have to type in indianamilitary.org, its not working even if u copy and paste

I found some major blunders in their aircraft histories. One is especially egregious as it has been proven conclusively to be myth. The website states the following:

"In combat, the Ki-100-Ia proved to be an excellent fighter, especially at low altitudes. It possessed a definite ascendancy over the Grumman F6F Hellcat. In one encounter over Okinawa, a Ki-100-equipped unit destroyed 14 F6F Hellcat fighters without loss to themselves. When the Ki-100 encountered the P-51D Mustang at low or medium altitudes over Japan, it was able to meet the American fighter on more or less equal terms."

This myth has been perpetuated by several aviation authors of rather low esteem within the circle of aviation historians. From what I can determine, Rene J. Francillon was the originator of this myth. I've read some of his work, and if he manufactured life vests, he's be making them from cast iron. It just so happens that this website lists Francillon as a source...

Francillon's exact quote was:

"It possessed a definite ascendancy over the Grumman F6F Hellcat. In one encounter over Okinawa, a Ki-100-equipped unit destroyed 14 F6F Hellcat fighters without loss to themselves. When the Ki-100 encountered the P-51D Mustang at low or medium altitudes over Japan, it was able to meet the American fighter on more or less equal terms. The outcome of P- 51D vs Ki-100 battles was usually determined by piloting skill or by numerical advantage rather than by the relative merits of the two fighter types."

The fact that no Ki-100s were in squadron strength service during the Okinawa campaign apparently eluded Francillon.

Navy records do not show anything close to Francillon's claim. What they do show is that in late July of 1945 a high gaggle of Ki-100s attacking a group of F6Fs beating up a Japanese airfield. They resulting combat left two Ki-100s down from gunfire and another collided with an F6F, both planes being lost (although the American bailed out of his damaged fighter, the Japanese pilot didn't). Another F6F suffered damage from tripleA and ditched off the coast, the pilot being rescued by an American sub.

Anyway, I'd take anything presented on that website as questionable at best, worthless at worst.

My regards,

Widewing

Kweassa · « **Reply #11 on:** January 15, 2008, 09:02:36 AM »

I seem to remember a discussion of this very subject when Ki84 was first introduced... and some following discussions after that Wotan came up with an interesting argument that the Ki84 very well may have been much faster than the claimed 398mph despite Japanese quality control and inferior fuel grade.

I seem to recall it was an argument based on something to have to do about the "slower" Ki84 being mishandled in American testings or something... but I can't remember any details (verdammt!).

And.. I am a terrible forum scavenger. Been rummaging through the search forums but can't seem to find the thread...

Kweassa · « **Reply #12 on:** January 15, 2008, 09:07:05 AM »

I did find this thread, though, which contains some of the arguments I've seen, but not the whole deal.

SgtPappy · « **Reply #13 on:** January 15, 2008, 07:06:40 PM »

Nice thread, I read it. Apparently, someone stated that 100/130 grade octane was used to give the Ki-84 its amazing performance. It was also stated that Japanese fuel with methanol/water injection would yield better performance than 100/130 grade octane alone.

At any rate there we have it. The Ki-84 has amazing performance... better speed than any PTO Allied or Axis plane operating.

Doesn't mean that it would be unbeatable though.

angelsandair · « **Reply #14 on:** January 15, 2008, 10:21:40 PM »

o and the link i got i think it was from the 70s........another setback about googling stuff, still some of it is kind of cool