Hello Tomo Pauk,
Bunrin Do is somewhat intermittent in reliability at best. The data on maximum speeds simply defies logic when matched against other sources such as the tests of Koga's A6M2 and captured manuals.
Not every speed test went the same, even when nominally same version of aircraft and engine were tested, on same boost. Same timng happened in other countries, with variances of 10 mph recorded.
Adding weight and drag should slow an aircraft down, and will lower it's RoC, provided the thrust was not improved a good deal.
I do not believe the Kasei would have been a viable fighter engine in its original versions. The developments for the version that was eventually installed in the J2M not only added the extension shaft and cooling fan but also added about 250 HP.
Not 250 HP, but ~50 HP. Not having extension shaft does not mean we loose extra power.
Granted, 'my' Japanese fighter will be slower by 5-10 mph, but it will be climbing better, and more importantly, it should be available in better numbers so it can replace Zero.
Probably the best Kasei version was the 'normal' type, installed on the latest Betty bombers, 1480 HP at 21600 ft per TAIC doc.
Without the extra streamlining from the extension shaft, I don't believe the performance would have been nearly as good.
As for the J2M as a carrier fighter or a floatplane, I don't believe either would be a workable concept. The J2M was fairly short ranged even though it carried about 700 liters of internal fuel. It was really a point defence interceptor. As a contrast the A6M3-22 and A6M5-52 carried 570-590 liters depending on sources.
I've never suggested the J2M to be converted into a carrier-borne fighter. IJN needs to request a new carrier-borne fighter, not a land-based interceptor.
The N1K Kyofu wasn't that fast either, but it WAS about 30-35 MPH faster than a A6M2-N and had about 500 feet per minute better climb.
If you really want a floatplane fighter, make such a version of the next-gen carrier-borne fighter, instead of developing a brand new type for such a task.
How many of these alternative directives and plans are a result of perfect hindsight and already knowing what did NOT work?
I am not convinced that too many alternatives would have worked much better with the design resources that were available.
The Japanese aircraft industry would have been much more effective if they had concentrated development on air defence instead of long range power projection from about 1940-1941, but at the time, they probably had other ideas as to how a short victorious war was going to go.
- Ivan.
Japanese know that Entente out-produced Germany and A-H by large margin back in ww1. They know that Germany and UK are making aircraft in thousands by 1940, and by extension that USA will be able to make as much as those two countries combined. They also know their industry can't match it. Yet, instead of ruthless reduction of types of aircraft during 1940-43 so there is a gain from economy of scales, they try to solve almost each task with a dedicated aircraft type (times two since there are two military services).
I have no problems with Japanese making a good effort on long range aviation. Their mistake was that early long-range fighter types, powered by 1000-1200 HP engines, were not replaced by new long-range types powered by 1500-1900 HP engines, with improved protection, firepower, dive speed and rate of roll, nor the early types have gotten any engine power increase worth talking about until too late.