A better Ki - 61

[La Rouge Beret]

Inspired by the Hawker Hurricane and BF - 109 threads.

How could one of the more numerous Japanese Army Air Force fighters of WW II be improved?

One of my initial thoughts would be to improve the visibility from the cockpit itself.

 

[Chris Triangle]

Improving cockpit visibility might be good and would be relatively easy but improving engine reliabillity would be even better for that plane. Kawasaki could start production of the Daimler Benz earlier (or any liquid cooled v-12) thereby better familiarizing mechanics with its design. Of course, they never managed to do that and eventually just put a radial on it to make the KI-100.

Personally I think they should have concentrated on replacing the KI-43 with the tougher, fast and harder hitting KI-44. Pilots hated it but it was quite a good interceptor.

 

[Just Leo]

When quantifying the qualities of the Ki-61, we can compare its performance with contemporary fighters with the DB-601 engine, the Me-109, the Regianne Re2001, and the Macchi MC202. They all found that more engine power was needed, and the engine industry in Japan failed to solve certain problems that arose with increased mechanical and thermal stress. While the Japanese industry strove to solve these problems, a miraculous radial appeared just a little too late to be timely, and a better canopy was installed too late to be significant. The tide had turned, and the chasm in performance between the Ki-61 and the various American aircraft of newer manufacture, flown by well-trained pilots, was never to be bridged.

 

[Chris Triangle]

When quantifying the qualities of the Ki-61, we can compare its performance with contemporary fighters with the DB-601 engine, the Me-109, the Regianne Re2001, and the Macchi MC202. They all found that more engine power was needed, and the engine industry in Japan failed to solve certain problems that arose with increased mechanical and thermal stress. While the Japanese industry strove to solve these problems, a miraculous radial appeared just a little too late to be timely, and a better canopy was installed too late to be significant. The tide had turned, and the chasm in performance between the Ki-61 and the various American aircraft of newer manufacture, flown by well-trained pilots, was never to be bridged.

Do you know whether the KI-100 was roughly equivalent in performance to or significantly superior to the KI-61?

 

[Just Leo]

Do you know whether the KI-100 was roughly equivalent in performance to or significantly superior to the KI-61?

Yes. It was superior to the earlier Ki-61 in performance. It was equal in performance to the later Ki-61, but superior in reliability. When production of liquid-cooled engines terminated, it had a definite edge in availability.

Your mention of the Ki-44 reminds me of a previous thread where I promulgated a theory that a better aircraft would have resulted from blending the larger wing area of the fighter with the larger engine of the intercepter, in the case of the Ki-43/44 and A6M/J2M. Their performance, while superior, would remain inferior to several later American fighters in performance, quantity, and quality of pilot training. Historically, individual Japanese pilots in good aircraft gave stellar performances right to the end, but wars are decided by greater numbers, and Japan lost "the game" in both planes and pilots, in quantity and in quality.

 

[Chris Triangle]

Yes. It was superior to the earlier Ki-61 in performance. It was equal in performance to the later Ki-61, but superior in reliability. When production of liquid-cooled engines terminated, it had a definite edge in availability.

Your mention of the Ki-44 reminds me of a previous thread where I promulgated a theory that a better aircraft would have resulted from blending the larger wing area of the fighter with the larger engine of the intercepter, in the case of the Ki-43/44 and A6M/J2M. Their performance, while superior, would remain inferior to several later American fighters in performance, quantity, and quality of pilot training. Historically, individual Japanese pilots in good aircraft gave stellar performances right to the end, but wars are decided by greater numbers, and Japan lost "the game" in both planes and pilots, in quantity and in quality.

That is interesting. I suppose the KI-100 would be the best realization of that sort of design. Were you suggesting that the KI-44 should have been given bigger wings?

 

[La Rouge Beret]

So in summary should the designers have used a radial engine from the start?

Alternatively if they persisted with an inline engine was there anything that they could have done to improve the reliability of the engine?

Could the armament have been improved or the wing area made larger? Apart from effecting lift, what other benefit does it bestow?

 

[Just Leo]

That is interesting. I suppose the KI-100 would be the best realization of that sort of design. Were you suggesting that the KI-44 should have been given bigger wings?

The Ki-44 had 15 sq. m of wing area with a 31 ft span.(9.45 m) All other Japanese fighters had 20 or more, including the J2M. The Ki-61/100 had 20. So, yes, I'm saying that. I even drew that conclusion.

 

[Just Leo]

So in summary should the designers have used a radial engine from the start?

Alternatively if they persisted with an inline engine was there anything that they could have done to improve the reliability of the engine?

Could the armament have been improved or the wing area made larger? Apart from effecting lift, what other benefit does it bestow?

The Kinsei radial was at the end of its development cycle, except for turbo development, which would have failed. Had they installed a less developed version earlier, they would get less performance. The engine desired for the Zero was the Kinsei, which also appeared very late in the war in the A6M8. War doesn't always wait for development.

The Ha-140 engine wasn't going to be developed until superior bearing materials and machining processes were developed. Same goes for the miraculous Homare radial which was incredibly small, light and powerful, but mostly unreliable. A small, very dense engine produces lots of heat, with poor dissipation characteristics.

Nothing wrong with the armament, although a shorter, broader wing of similar area would impart a slightly better performance IMHO.

 

[zoomar]

The Ki-61 itself was a 1940-41 design concept wedded to the DB-601 engine. Unlike the Bf-109 itself or the Italian Mc 202/205 or G-55, the Japanese did not have ready access to improved DB series engines (the 603 or 605) to substantially improve the plane's speed and altitude capabilities. The improvements that were possible (the all-round vision cockpit in the Ki-61III, increased armor protection, or strengthening the wings to perhaps permit the fitting of additional cannon armament) would not have improved performance (and in the case of the cannon and increased protection might have worsened it)

As far as I can tell, the published literature is not unanimous on whether the radial engined Ki-100 was actually an improvement on the Ki-61. Most likely it was about as good, with the advantage that the radial engines were available and more reliable, with apparent disadvantage of a somewhat slower maximum diving speed. Possibly, had the Japanese designed the plane from the outset for increasingly powerful radials rather than the DB-601, there could have been more Ki-61s, they would be more reliable, and they'd have better stretch. Arguably, however, without the German influence that was partially behind the design of the Hein, radial-engined Ki-61s might have had the same flaws as other 1940-41 vintage JAAF designs (weaker armament, complete lack of protection, etc). Considering that Ki-61s did not reach squadrons in large numbers until early 1943, the much superior Ki-84 with its (unreliable) Homare radial was almost ready - the only fully modern fighter fielded by the JAAF.

 

[Chris Triangle]

The Ki-61 itself was a 1940-41 design concept wedded to the DB-601 engine. Unlike the Bf-109 itself or the Italian Mc 202/205 or G-55, the Japanese did not have ready access to improved DB series engines (the 603 or 605) to substantially improve the plane's speed and altitude capabilities. The improvements that were possible (the all-round vision cockpit in the Ki-61III, increased armor protection, or strengthening the wings to perhaps permit the fitting of additional cannon armament) would not have improved performance (and in the case of the cannon and increased protection might have worsened it)

As far as I can tell, the published literature is not unanimous on whether the radial engined Ki-100 was actually an improvement on the Ki-61. Most likely it was about as good, with the advantage that the radial engines were available and more reliable, with apparent disadvantage of a somewhat slower maximum diving speed. Possibly, had the Japanese designed the plane from the outset for increasingly powerful radials rather than the DB-601, there could have been more Ki-61s, they would be more reliable, and they'd have better stretch. Arguably, however, without the German influence that was partially behind the design of the Hein, radial-engined Ki-61s might have had the same flaws as other 1940-41 vintage JAAF designs (weaker armament, complete lack of protection, etc). Considering that Ki-61s did not reach squadrons in large numbers until early 1943, the much superior Ki-84 with its (unreliable) Homare radial was almost ready - the only fully modern fighter fielded by the JAAF.

Yet I seem to remember hearing that tests showed the KI-100 to be a superior aircraft to the KI-84 in spite of its lower top speed. Of course knowing the Japanese, that might have only meant that it was found to be more maneuverable.

 

[Just Leo]

Yet I seem to remember hearing that tests showed the KI-100 to be a superior aircraft to the KI-84 in spite of its lower top speed. Of course knowing the Japanese, that might have only meant that it was found to be more maneuverable.

There was a "10 Best Fighters" program on TV and the tenth was the F-117, not a fighter. An opinion is just an opinion, unless it's mine, although I don't always agree with that. The Frank, with a hot pilot, was great, but with the commonly recalcitrant engine, it was an awkward doorstop. I've heard it said that it was faster than a Mustang at certain altitudes. However, the Mustang changed the course of war, and you can't say the same for the Nakajima. It still had to battle the late Oscars for room on the production line.

 

[La Rouge Beret]

Okay gents.

In essence for my rebooted TL I was envisaging a Jungle airforce initially until lack of spares / fuels grounds said aircraft.

Now with various comments in this thread would it be better for my embryonic VNAF to utilise Ki - 43's, being a far easier machine to maintain and utilise?

 

[Just Leo]

Okay gents.

In essence for my rebooted TL I was envisaging a Jungle airforce initially until lack of spares / fuels grounds said aircraft.

Now with various comments in this thread would it be better for my embryonic VNAF to utilise Ki - 43's, being a far easier machine to maintain and utilise?

I don't recall any post-war usage of the Ki-100, although the Ki-84 and Ki-43 saw some use by Mao, and the French in Indochina operated Ki-43 III Oscars until replaced.

 

[La Rouge Beret]

That's my thought... as good as it would be to have some tricked out aircraft.

A Ki - 43 would be useful for some nuisance raids.