The real combat history of the Ki-43

[AerialTorpedoDude69]

How about a shot of a KI-43 and an A6M3?

That image is super appropriate for this discussion. That Ki-43 IIRC was rebuilt from several Ki-43-IIIa wrecks from the Kuriles. Possibly one of the Oscars from the Battle of Shumshu.

Segue here: interesting to note is that the restorers removed the water-methanol injection system because, in order to make it airworthy, they had to use an R-1830, which did not have MW50 injection AFAIK. Greg from Greg's Automobiles and Aircraft is skeptical that the Ki-43-IIIa had MW50 injection except as a prototype, according to his video on the ki-43.


View: https://www.youtube.com/watch?v=Enff_CVSoC0

 

[AerialTorpedoDude69]

Accidental double post fellas. Sorry. How do I erase this thing?

 

[GrauGeist]

Accidental double post fellas. Sorry. How do I erase this thing?

We've never been able to delete a post (that's how the forum has always been).

 

[SaparotRob]

Just stumbled on this Picture
View attachment 843087

Caption - A rare combat photograph of a Japanese Ki-43 Hayabusa (Allied reporting name "Oscar") intercepting USAAF B-25 Mitchells over the Kurile Islands, November 6, 1944. A close examination of the Oscar shows that one of the landing gear is lowered, likely indicating damage to the hydraulic system.

Source Picture of the Week – Page 3 – Inch High Guy

Two different models of B-25 as well!

 

[andrewgeorge]

Nice shot. Always thought Ki-43 was the more sleek and elegant machine of the two. A6M always looked just a little too much like a flying cigar for my taste.

Strip the guns off the thing and give it a bright, happy paint job and it would be a wonderful, simple, little sport plane with lines that couldn't get much cleaner.

 

[SaparotRob]

I wasn't aware of the Ki-43, Ki-44, Ki-61 and others for many years. The IJAF didn't get much air time in the histories that interested me. As such, my all-time favorite "bad guys" airplane was the Zero. It will always be the best looking one of the bunch to me for few logical reasons.
I love the B-17 but the A6M is my forbidden fruit.

 

[andrewgeorge]

I wasn't aware of the Ki-43, Ki-44, Ki-61 and others for many years. The IJAF didn't get much air time in the histories that interested me. As such, my all-time favorite "bad guys" airplane was the Zero. It will always be the best looking one of the bunch to me for few logical reasons.
I love the B-17 but the A6M is my forbidden fruit.

I suspect part of the reason is because a lot of the popular histories about pilots in the Asia/Pacific air war are really warmed-over repetitions of the same published content that dates back to the years of the war itself, and is full of inaccuracies—some from wartime confusion and some the result of deliberate propaganda. During the war, pilots didn't always know if they were engaged with enemy army or navy planes, and "Zero" became basically just the default shorthand for "single radial engine Japanese fighter."

So wartime stories about, say, the Flying Tigers developing crafty tactics for fighting "Zeros" in Burma and China have gotten repeated ad nauseum up through the present, even though almost all AVG air combat in the first weeks of the war would have been with IJAAF Ki-27s and then later with greater numbers of Ki-43s.

American army pilots in 1943-1944 New Guinea would often claim "zeros" shot down when, in retrospect with fuller knowledge of Japanese operational histories, they were definitely engaged with army planes.

I've learned a lot more in the last few years as I decided to get back into model building (an excellent wintertime hobby in cold climates I've discovered!) and realized basically everything I read about in 50s and 60s era popular histories of WWII aviators and aviation when I was a kid was at least somewhat wrong.

 

[AerialTorpedoDude69]

In the 1990s I read a book from the 50s which mentioned that a pilot in the CBI claimed to have shot down an Oscar III. And then the author specifically mentioned that this was not like shooting down a zero. The Oscar III was a dangerous aircraft.

I had assumed that they meant a Frank, but after reading everything in this thread, it seems more likely that the Oscar III really did have a good reputation, particularly given its low-altitude acceleration. It reportedly had unusual performance at low to medium altitude.

 

[beers]

Hi beers (love your handle) and welcome aboard.

Thanks! It's even funnier if you consider that I don't drink alcohol at all.

but because local pressure disturbances caused by the aircraft itself cause the indicator to misread.

Yeah, I wrote something like this in a previous reply. What the indicators show isn't exactly what the plane is doing, for the Spitfires I believe the correction charts only go down to 120mph but the trend is that it reads lower and lower and someone unaware of it would assume it has a much lower stall speed than it really does.

Always thought Ki-43 was the more sleek and elegant machine of the two. A6M always looked just a little too much like a flying cigar for my taste.

The Ki-43's canopy must have been the envy of many. So little framing, relatively roomy inside, really no blindspots anywhere as even the headrest is narrow. Undoubtedly contributed to its surprisingly good results in combat. If this plane was ahead of the rest in any regard, it was right there.

And then the author specifically mentioned that this was not like shooting down a zero. The Oscar III was a dangerous aircraft.

Seems like it also didn't suffer much from control lockup, I have only ever seen it mentioned for the Zero. Roll rate must have been impressive.

 

[AerialTorpedoDude69]

Seems like it also didn't suffer much from control lockup, I have only ever seen it mentioned for the Zero. Roll rate must have been impressive.

Its lighter weight and poorer streamlining meant that the Oscar probably didn't dive as well as zero and so didn't hit the speed at which control stiffening occurs as rapidly.

Slower dive would give the illusion of it not suffering from control stiffening. But a simple rule of thumb is that control stiffening is based on the speed of air traveling over the control surfaces and the relative size of the control surface. The bigger the control surface, the more high speed air stiffens control.

I think airfoil design might also impact control stiffen as well as servos. But it used a very generic airfoil and didn't have any assistive aileron technology.

 

[andrewgeorge]

Its lighter weight and poorer streamlining meant that the Oscar probably didn't dive as well as zero and so didn't hit the speed at which control stiffening occurs as rapidly.

Slower dive would give the illusion of it not suffering from control stiffening. But a simple rule of thumb is that control stiffening is based on the speed of air traveling over the control surfaces and the relative size of the control surface. The bigger the control surface, the more high speed air stiffens control.

I think airfoil design might also impact control stiffen as well as servos. But it used a very generic airfoil and didn't have any assistive aileron technology.

It definitely stiffened up at higher speeds, from what pilots who flew it have said (that I've read anyway). Ki-44 on the other hand was substantially better than Ki-43 with high speed roll rate, although it stiffened a bit too.

Heavy high speed controls were really kind of a (relative) problem in most Japanese fighters during the war.

 

[beers]

Heavy high speed controls were really kind of a (relative) problem in most Japanese fighters during the war.

You'll find even P-51 pilots complaining about how it handled at high speeds, the question is how bad it was. My point was that it very likely wasn't as bad as the Zero because it's not really mentioned anywhere. Absence of evidence is not evidence, but you'd think japan's most produced fighter would have some relatively widespread information about a major weakness like this.

For example, Bunrindo's Famous Airplanes Of The World book on the Ki-43 doesn't spare criticism of its flaws, but somehow doesn't mention control compression anywhere? It's a little suspicious.

Its lighter weight and poorer streamlining meant that the Oscar probably didn't dive as well as zero and so didn't hit the speed at which control stiffening occurs as rapidly.

Dive limit was about the same as every Zero before the Model 50s, somewhere in the low-mid 600kph range - not great, but usable. Ha-115 engine was very very similar with close critical altitudes for its supercharger to the Sakae 21, so that wouldn't be much of a difference either.

 

[andrewgeorge]

You'll find even P-51 pilots complaining about how it handled at high speeds, the question is how bad it was. My point was that it very likely wasn't as bad as the Zero because it's not really mentioned anywhere. Absence of evidence is not evidence, but you'd think japan's most produced fighter would have some relatively widespread information about a major weakness like this.

For example, Bunrindo's Famous Airplanes Of The World book on the Ki-43 doesn't spare criticism of its flaws, but somehow doesn't mention control compression anywhere? It's a little suspicious.

Dive limit was about the same as every Zero before the Model 50s, somewhere in the low-mid 600kph range - not great, but usable. Ha-115 engine was very very similar with close critical altitudes for its supercharger to the Sakae 21, so that wouldn't be much of a difference either.

Interesting point. Also notable that subsequent Nakajima fighters—Ki-44 and Ki-84 were certainly handle-able at higher speeds, even if controls got stiffer.

Also worth pointing out that even the Zero-sen as an aircraft was a perfectly useful fighter plane, even later in the war. Its weaknesses (and those of the Ki-43) were all relative—it was a high performance fighter plane that could still outclimb and, under 250 knots, outturn any American fighter through the end of the Pacific war.

 

[AerialTorpedoDude69]

You'll find even P-51 pilots complaining about how it handled at high speeds, the question is how bad it was. My point was that it very likely wasn't as bad as the Zero because it's not really mentioned anywhere. Absence of evidence is not evidence, but you'd think japan's most produced fighter would have some relatively widespread information about a major weakness like this.

For example, Bunrindo's Famous Airplanes Of The World book on the Ki-43 doesn't spare criticism of its flaws, but somehow doesn't mention control compression anywhere? It's a little suspicious.

Dive limit was about the same as every Zero before the Model 50s, somewhere in the low-mid 600kph range - not great, but usable. Ha-115 engine was very very similar with close critical altitudes for its supercharger to the Sakae 21, so that wouldn't be much of a difference either.

There was a 400kg difference between the operational weights of the A6M2 and Ki-43-I. The Ki-43-I also had much poorer streamlining compared to the A6M2. In a dive, the A6M2 would have had control stiffening much sooner than the Ki-43-I. I don't know what the surface area was of the control surfaces on either aircraft, but if the Ki-43-I had smaller control surfaces, then it would have had reduced control stiffening compared to the A6M2.

Bunrin-do has a schematic of the Ki-43-II's control surface length on page 82, but nothing regarding its surface area. But my guess is that the Ki-43's designers may have used smaller control surfaces compared to the Zero because it had combat flaps.

 

[UnderPressure]

In the 1990s I read a book from the 50s which mentioned that a pilot in the CBI claimed to have shot down an Oscar III. And then the author specifically mentioned that this was not like shooting down a zero. The Oscar III was a dangerous aircraft.

I had assumed that they meant a Frank, but after reading everything in this thread, it seems more likely that the Oscar III really did have a good reputation, particularly given its low-altitude acceleration. It reportedly had unusual performance at low to medium altitude.

Yeah, that seems to be the case. According to Sgt. Ikeda, Ki-43-III actually had better acceleration than not only the Model II, but even the Ki-44 and Ki-84. In mock dogfights, it reportedly outclassed the Ki-44 pretty easily. Compared to the Ki-84, Frank was faster overall and had a better cruising speed, so it was better at chasing down enemies or diving away to escape. Because of that, quite a few pilots flying the Ki-43-III still preferred to get their hands on a Ki-84.

There's also this postwar story where they flew alongside a Spitfire Mk.XIV at low altitude — and the Ki-43-III managed to keep up with the Mk.XIV through a dive, low-level pass, and even a steep climb. But there's a twist: another postwar story says a Ki-46 raced a Spitfire, and the Spit caught up easily (even though the Ki-46 had a head start), passed it, and even looped over it. The guy who told that story later said the Spitfire pilot was probably just taking it easy with the throttle during that earlier formation flight.

As for actual combat, there are two cases we know of. One was on January 5, 1945, when a Spitfire VIII may have shot down a Ki-43-III. In that fight, four Ki-43s from the 64th Sentai were heading back low after a bombing run when four LF Mk.VIIIs from 81 Squadron bounced them from about 600–800 ft higher. Three got shot down, and one was damaged and had to crash-land. That one was flown by Lt. Col. Eto, the squadron leader, and it looks like he'd switched to the Ki-43-III back in September 1944.


The other case is from Sgt. Ikeda himself.he said that right after he started flying the Ki-43-III, a P-38 blew his aileron clean off.However, I haven't been able to track down the actual combat data for this fight yet.

When it comes to actual combat, it might seem like the Model III was just getting shot down all the time, but that's mainly because there were so few of them to begin with, and I don't have much information on the Ki-43-III in the books I own Looking at sources like Shores and Hiroshi Umemoto's books and counting from October 1944 to the end of the war, the 64th Sentai is credited with shooting down 3 Mosquitoes, 1 Beaufighter, 1 L-5, 3 P-47s, 2 Hurricanes, and 1 Spitfire. Unfortunately, I have no idea how many of those were actually Ki-43-IIIs.

 

[beers]

Yeah, that seems to be the case. According to Sgt. Ikeda, Ki-43-III actually had better acceleration than not only the Model II, but even the Ki-44 and Ki-84. In mock dogfights, it reportedly outclassed the Ki-44 pretty easily. Compared to the Ki-84, Frank was faster overall and had a better cruising speed, so it was better at chasing down enemies or diving away to escape. Because of that, quite a few pilots flying the Ki-43-III still preferred to get their hands on a Ki-84.

Not the first time I've heard that...

(from bunrindo, "allied impressions" section)

Automatic translation from a poor scan so the wording is a bit rough. Amusingly, "by the seat of pants" is written in english.

 

[AerialTorpedoDude69]

All those reports of good acceleration support the Ki-43-IIIa having water-methanol injection. Otherwise, how is it possible for the -III to out-accelerate the -II, despite weighing more?

 

[andrewgeorge]

All those reports of good acceleration support the Ki-43-IIIa having water-methanol injection. Otherwise, how is it possible for the -III to out-accelerate the -II, despite weighing more?

Wasnt Kinsei 61 a somewhat more powerful engine than (Sakae) Ha-115?

Kinsei 61 always had option for water-methanol injection didn't it?

 

[AerialTorpedoDude69]

Wasnt Kinsei 61 a somewhat more powerful engine than (Sakae) Ha-115?

Kinsei 61 always had option for water-methanol injection didn't it?

That's a good question. It seems that the Kinsei 61 was never mounted to the Ki-43 airframe, according to Bunrin-do. Nakajima worked on adapting the Homare Ha-45 to the Ki-43-IV, but this project was scrapped. It seems that Francillon mixed up the names of the Kinsei and the Sakae, as they have similar designations.

I believe Laurelix published about this as well and they are completely right. There's no supporting documentation in the Japanese materials (Maru Mechanic, Bunrin-do, Wikipedia, etc...) which points to there being a Kinsei-powered Ki-43. The only source which originally had this was Francillon.

 

[beers]

Wasnt Kinsei 61 a somewhat more powerful engine than (Sakae) Ha-115?

The Ha-112 (Kinsei in IJN naming) wasn't ever fitted to the Ki-43, this was a typo in Fracillion's book that never got corrected. It was much more powerful, late models of both engines would have been around ~1500hp and ~1200hp respectively.

There was also a short-lived proposal to fit the Ha-45 Homare (now unified designation) to the Ki-43. For maybe obvious reasons it never went anywhere.