Japan’s worst single-engine radial-powered fighter of WW2?

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Admiral Beez

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Oct 21, 2019
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I've read that the Ki-44 was considered a backward step from the Ki-43. Which was Japan's worst single-engine radial-powered fighter of WW2?

One possible measure is how it compares against other aircraft of the same year. For example, the Ki-27 entered service in 1938, the same year as the Spitfire. Another measure can be execution, the Mitsubishi J2M seemed to be beset by problems.
 
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I don't consider the Ki-27 to be a WWII fighter. The Boeing P-26 was flown in very early WWII by the USA and I don't consider IT to be a WWII fighter, either despite it actually being in the war. If I had to include the Ki-27, I'd pick it as the worst.

To me, the worst of the rest was the Ki-43 Hayabusa. It flew beautifully and was exceptionally maneuverable. But, it had very light armament until it's last version (only 2 built), no armor at first, and no self-sealing tanks. So, the vast majority of Ki-43s ... probably over 95% of them ... that served were of the under-armed and under-armored variety. This did not stop them from being effective at first, but DID mean they weren't as good as later radial fighters, including the J2M Raiden, which was one of the very few Japanese fighters that stood a chance of intercepting a B-29.

The fact that they made few of them and that a decent percent of the ones they made didn't really perform up to snuff does not detract from the ones that DID perform well. The ones that performed well validated the design as a good one.

But, hey, opinions differ and I suppose one of the approximately 21 other fighters, all but one of which were powered by radials, COULD be worse. I think the Japanese did a pretty good job with fighters, given the engines and war situation they had to work with. They might not have been up to the task of being fighters in the ETO, but they DID manage to embarrass the Spitfires that showed up in the Pacific around Darwin, and the Spitfire is usually in the running for "best fighter of the war" in most people's book. So, how bad could Japanese fighters have been? Answer is, "Not bad, all things considered!"
 
The Ki-44 was designed from the ground up as an interceptor with an accent on climbing performance.

While for the average Japanese pilot of the day the Ki-44 might have seemed 'sluggish' it was not a bad design. If I remember correctly it was tested also against a FW-190 with good results. It was very successful as a bomber destroyer.

To me, any ww2 Japanese plane that was fielded with a Homare is a bad design Just kidding, but the truth is that even when it was working, that engine was stretching technology of the day to the limit. As a result of its compact design, its cylinder head temperature was very high, and this raises questions about its reliability, especially when (if) used with high octane gasoline at its design power.

The real problem of Japanese air doctrine was that they imagined that air battles would be fought like in ww1. As a result, they had highly skilled pilots in acrobatics, but little group tactics. So the air battles in which the Japanese were involved became more like a series of individual skirmishes in which a pilot would try to hunt down an enemy plane on its own. This philosophy also affected how they designed their planes.
 
Americans think WW2 started in late 1941
Euros think WW2 started in late 1939
Chinese think WW2 started in 1937

So I vote Ki-27/A6M5
In 1940 they were inferior to the chinese/russian flown I-153 and late I-16 models.
 
To me, the worst of the rest was the Ki-43 Hayabusa. It flew beautifully and was exceptionally maneuverable. But, it had very light armament until it's last version (only 2 built), no armor at first, and no self-sealing tanks.
It is surprising that the Japanese would introduce fighters in 1941 with no better armament or protection than a Sopwith Camel. Did their embassy in London not tell Tokyo that the Battle of Britain had just been won by RAF fighters fielding eight machine guns, SS fuel tanks (not all aircraft yet) and armour?
 
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Sorry Admiral Beez.

Reference Post #4 where Timppa suggest the A6M5 as one of the worst. No way… It ruled the skies from the time it came out until the Hellcat arrived.
The A6M5 entered service after the Hellcat, and for that matter after the Tempest, Corsair, Lavochkin La-5 and Fw 190A-4. In that sense, if we're going to look at separate variants of each aircraft the A6M5 can be considered a poor aircraft.

Unlike the earlier and ferociously-victorious A6M2, I do not believe the A6M5 ever ruled the skies. The IJN of 1943 needed something with the performance, protection and firepower of the Nakajima Ki-84, not a worked over Zero with late 1930s performance and protection.
 
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I agree Admiral, but I also agree with you, Greg, the A6M5 was well past the airframe's sell-by date; the A6M had been bested with the arrival of the F6F. I don't know if it qualifies as the worst, since in a good pilot's hands or to an unwary Allied pilot the A6M5 was still a formidable foe thanks to its excellent low-speed manoeuvrability.

I would vote the Ki-60/Ki-61 as the worst radial engined single seat fighter Japan used.
It was so bad at being a radial engined fighter, they had to put the cylinders inline with each other, with coolant pipes just to keep it from overheating!
Ha ha! Both designed from the outset with inline engines, of course...

Hard to say what the worst was, the Japanese relying on the configuration throughout the war for both army and navy fighters, the latter carrier and land-based. The J2M was hampered by its low service ceiling and a turbo-supercharged variant was built but was terminated before the war's end, not to mention the type's engine cooling problems. This latter issue made the J2M unreliable and throughout its career, it was plagued with maintenance issues and so it's a possible contender.

The Ki-44 design was a different concept to the Ki-43 and proved excellent in the climb and dive and this made a very good interceptor, for which it was designed, so it's hard to see it as a poor aircraft at all, despite the Japanese pilots not liking it because of its high landing speed and lack of manoeuvrability.
 
While the J2M has been praised postwar as an excellent combination of maneuverability and performance, ironically, the J2M might be the least accomplished of all the aircrafts fielded in numbers by the Japanese, the reason being that it wasn't given enough attention to mature into a sound design: Mitsubishi focus had always been on improving the A6M and building its successor, the A7M.

The Kasei engine wasn't a bad engine, in fact I'm a firm believer in that, had the N1K continued to use this engine in place of the Homare, it would have fared much better. The same could be said for a number of late war bombers and attack planes stuck with the Homare. The J2M employed a rather radical solution to 'hide' this large engine but, considering its top speed, it doesn't seem to be more effective than a typical ring cowling, while adding complexity and maintenance woes.
 
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Mitsubishi focus had always been on improving the A6M and building its successor, the A7M.

Mitsubishi was a big company and could afford to develop two different fighter programmes simultaneously, the navy division was also designing and building bombers too; it also had an army aircraft division as well that acted independently of the navy division. The J2M was built as a land-based fighter, not a carrier fighter and had lots of bugs that weren't ironed out. The A7M was beset with delays, hence the continuation in modifying the A6M well beyond when it should have been retired.

The Kasei engine wasn't a bad engine,

It wasn't but in the J2M it overheated because of the installation. The J2M was beset with mechanical problems and required frequent maintenance.
 
Mitsubishi was a big company and could afford to develop two different fighter programmes simultaneously,
Sure, but the J2M is the brainchild of Jiro Hiroshi, the same designer of the A6M and A7M. The fact that he suffered from chronic stress, and even had to take some time off work in 1944, is a telltale sign that his office was overseeing too many projects at a time.
 
The fact that he suffered from chronic stress, and even had to take some time off work in 1944, is a telltale sign that his office was overseeing too many projects at a time.
Yup, true. Most of his stresses were probably brought about by the continuing mechanical issues the J2M suffered, as well as the constant delays of the A7M and thus having to rework the A6M.
 
Per his biographical notes on Wikipedia he knew the war was lost on the first day, knowing that American industrial might would crush Japan. Of course he still did his best and his duty.

The Mitsubishi factories were being bombed to pieces, that had to be stressful, not knowing if your work will be there the next day.
 
Or not knowing if you'll be there the next day.
 

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