Japanese Zero vs Spitfire vs FW 190

[Shortround6]

The Kinsei's big brother was the Kasei.

Still 14 cylinders but 42 liters instead of 32.3 liters.
It powered the G4M and H8K among others, the Japanese considered it a large engine but it was no larger than the Wright R-2600, the BMW 801 or the Bristol Hercules.

I do think Tomo mixed up the names???

 

[cherry blossom]

My use of brother is possibly the wrong word as indeed the Kinsei and Kasei were the same generation. However, the 14 cylinders of the Kinsei 60 series were very similar to the 18 of the Ha-43 (unified) or MK9 (Navy). There was probably some development and the MK9 could take 520mmHg (50.4"), which was more than the Kinsei 50 series with 330mm (42.9"). Alas I don't know the boost of the Kinsei 60 series. Simply multiplying 1560 by 18 and dividing by 14 gives 2,000 ps but the MK9C gave around 2,200 ps.

PS. I just noticed that the MK9 could run at 2900 rpm compared to 2600 rpm for the Ha-112 II, which explains the extra power.

 

[Shortround6]

The HA-43 did use the smaller cylinders and because of that it had several advantages over the Kasei which was of roughly the same displacement.(0.3 liters out of 42 liters?)
The slightly smaller bore means it is a little easier to cool, the cylinder wall to cylinder volume is more favorable and the path from the center of the piston to the cylinder wall is a bit shorter.
The Shorter stroke may mean the engine/s with the shorter stroke can operate at a higher rpm than the long stroke cylinders in the Kasei, many sources do not give the RPM making this a bit difficult.
But it appears the Kasei on the later engines was limited to 2600rpm for take-off and 2500rpm for actual flying while the HA-43 was running at 2900rpm?

 

[Ivan1GFP]

Table is translation of data tables from the two books about Zero by Bunrin Do. We can take it for what it's worth.

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.

Diameter of the Kasei was not ridiculoulsy large. At 52.5 in, it was same as of the R-2800. Going for extension shaft not just introduced problems with vibrations, it upped the dry engine weight bs ~220 lbs, and required that Mitsubishi devotes engineering staff to design the ectual engine version. Kasei certainly worked as 'plain Jane' engine.
What materialized as the J2M needed to be designed as next-gen carrier-based fighter (waiting for A7M will not cut it), that can be also deployed at land bases and can receive floats so there is a better floatplane fighter to pick up from the A6M2-2.
Not going for counter-rotating version of the Kasei for the rex again means less strain on Mitsubishi engine design & prototype shop.

The N1K was also not that speedy - 300 mph.

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.
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.

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.

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.

 

[tomo pauk]

Has something gone wrong in the names? The most powerful Kinsei engines were the 60 series ( Ha-112-II, Ha-33-62) which gave 1,500 or 1,560 ps for take off with water injection. Are you talking about the Kinsei's big brother with 18 cylinders the Ha-43 or MK9?

The Kinsei's big brother was the Kasei.

Still 14 cylinders but 42 liters instead of 32.3 liters.
It powered the G4M and H8K among others, the Japanese considered it a large engine but it was no larger than the Wright R-2600, the BMW 801 or the Bristol Hercules.

I do think Tomo mixed up the names???

Yes, I'll edit the post(s?).

 

[tomo pauk]

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.

 

[Kevin J]

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.



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.



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.



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.



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.

Economies work best with multiple independent suppliers. Communist countries realised this in the end.

 

[Shortround6]

There is a difference between multiple independent suppliers that can bid on contracts and duplication of specifications and too many specifications. Both army and navy putting out specifications for long range, maneuverable fighters, and point interceptors, at the same time. 4 different programs, plus float fighters,
Then the twin engine bomber programs. There was too much duplication of effort for a country the size of Japan.

 

[Kevin J]

There is a difference between multiple independent suppliers that can bid on contracts and duplication of specifications and too many specifications. Both army and navy putting out specifications for long range, maneuverable fighters, and point interceptors, at the same time. 4 different programs, plus float fighters,
Then the twin engine bomber programs. There was too much duplication of effort for a country the size of Japan.

I don't see a problem with it.

 

[Ivan1GFP]

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.

Hello Tomo Pauk,

I have no argument that test results could differ substantially, but when a maximum speed for an aircraft matches EXACXTLY what is stated in the manual for the type under less than maximum power, then one has to question whether that was REALLY the maximum performance. I have actually never found a reliable maximum speed listing for the A6M3 series.
The performance numbers in the spreadsheet for A6M2 also match the US testing of an aircraft known to be in less than perfect condition.

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.

The point I was trying to make was that the developments on the engine were not just to add an extension shaft. There were quite a few more improvements in the versions used in the Raiden over other Kasei engines.
According to TAIC, the Kasei 23 used in J2M3 was capable of 1560 HP @ 18,100 feet and 1785 HP @ 16,600 feet and 1870 HP @ Sea Level.
With a bit less power and without the pointy nose and forced air cooling, I believe your alternative fighter would lose a lot more than 5-10 MPH in speed.

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.
c

The N1K Kyofu was one of the few really successful programs. Unfortunately the need for the type was overtaken by changes in the strategic situation.

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).

You and I are actually in agreement. IF they had any sense, they never would have entered the war to begin with.
It was not something that could be won with the balance of industrial power, but my understanding was that they believed it would be a quick war with a negotiated peace as had happened twice before in wars with China and Russia.

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.

Those early long range fighters never got replaced at all. Long range isn't really necessary when one is doing nothing but defending.

- Ivan.

 

[MiTasol]

The point I was trying to make was that the developments on the engine were not just to add an extension shaft. There were quite a few more improvements in the versions used in the Raiden over other Kasei engines. With a bit less power and without the pointy nose and forced air cooling, I believe your alternative fighter would lose a lot more than 5-10 MPH in speed.

Your heavier engine with shaft and fan now needs the firewall moved even further aft or a lot of additional weight in the tail. That will probably cost a lot more than 5-10 mph also

 

[taly01]

. The Zero might also have had a problem with structural failure if it were able to deflect its ailerons enough at high speed. Do you have an opinion on that

The early A6M2 Zero had serious problems with wing strength and aileron flutter at high speeds and some were lost in testing while trying to find its limits! The book "Zero: Combat and Development" by Robert Mikesh (from MotorBooks International) covers the complicated history of aileron mass balancers and aileron reverse assist tabs. By the time of the A6M5 all these "do-hickeys" were engineered out by good design.

It seems we want the same thing, a four gun airplane that will do around 360mph, dive better and still maneuver close to the Ki-43. .......

The IJAAF did have the solution fighting in the front line by mid-43, the Ki-61, but its engine turned out to be an unreliable maintenance nightmare!
One of the US post war surveys deduced ~65% of Japanese aircraft design was spent on improving old (correction) designs until 1944, this turned out to be a big error.

 

[Shortround6]

The IJAAF did have the solution fighting in the front line by mid-43, the Ki-61, but its engine turned out to be an unreliable maintenance nightmare!
One of the US post war surveys deduced ~65% of Japanese aircraft design was spent on improving new designs until 1944, this turned out to be a big error.

Did you mean "65% of Japanese aircraft design was spent on improving new designs until 1944"
or 65% of Japanese aircraft design was spent on improving new designs until 1944"
Just wondering as I am a bit confused by the statement.

The Engine used in the Ki-44 had potential for the the mid war years but the Japanese made the wing and fuel capacity of the Ki 44 too small. The Ki 44 was in production at the right time (in small numbers) but it's limited fuel capacity (short range) and high landing speed limited it's utility. A hypothetical plane with a wing roughly the same size as the Ki-43 and Ki 84 and a fuel capacity about 1/2 way inbetween to suit the power of it's engine might have been of much more utility than the Ki 44s extra few mph but limited deployability.

 

[tomo pauk]

The point I was trying to make was that the developments on the engine were not just to add an extension shaft. There were quite a few more improvements in the versions used in the Raiden over other Kasei engines.
According to TAIC, the Kasei 23 used in J2M3 was capable of 1560 HP @ 18,100 feet and 1785 HP @ 16,600 feet and 1870 HP @ Sea Level.
With a bit less power and without the pointy nose and forced air cooling, I believe your alternative fighter would lose a lot more than 5-10 MPH in speed.

'My' fighter will loose even more speed, since I want 1st and foremost a fighter that can 1st suplant and then replace Zero in all of it's iterations (carrier-based 1st, then as land-based fighter, then as a floatplane conversion) in a timely manner. And I want it all on the fighter - 4 cannons, protection for fuel and pilot, useful fuel tankage + drop tanks, good/very good/excellent speed, RoC, dive and roll; folding wing, and preferably the butterfly flaps. Designing a fighter around Kasei can provide all of that, Sakae will not cut it, and Homare is too late.

The N1K Kyofu was one of the few really successful programs. Unfortunately the need for the type was overtaken by changes in the strategic situation.

Okay, we'll install floats on 100 of the next-gen fighters so that mission is covered.

You and I are actually in agreement. IF they had any sense, they never would have entered the war to begin with.
It was not something that could be won with the balance of industrial power, but my understanding was that they believed it would be a quick war with a negotiated peace as had happened twice before in wars with China and Russia.

Japan never fought against several major powers in the same time, and they knew well that industry capacity of China was non-existing when compared with UK, let alone USA. Granted, Japanes going to war against 'West' in 1941 is a topic of it's own.

Those early long range fighters never got replaced at all. Long range isn't really necessary when one is doing nothing but defending.
- Ivan.

Deciding to just defend only means relinquishing initiative to the enemy. Long range is essential in the Asia/Pacific vast expanses, since it can allow for concentration of forces. Short range fighters based at Kyushu will have hard time to help out above Honshu and vice-versa. Defence of the Ryukyus demands long-range fighters, so does the air fight ove China.

 

[taly01]

Did you mean "65% of Japanese aircraft design was spent on improving new designs until 1944"
or 65% of Japanese aircraft design was spent on improving new designs until 1944"
Just wondering as I am a bit confused by the statement.

Ooopps I meant to write, a US post war survey deduced ~65% of Japanese aircraft design was spent on improving old designs until 1944, this turned out to be a big error.

 

[Glider]

Ooopps I meant to write, a US post war survey deduced ~65% of Japanese aircraft design was spent on improving old designs until 1944, this turned out to be a big error.

I would be interested to know what the UK and German figures would be. Think of the effort put into Hurricanes, Spifires, Wellingtons and if you take the start as Dec 1941, Stirling's, Halifax's Manchester's/Lancaster's Typhoons and no doubt others. As for the German its a similar story, 109, 190, Ju88 He111 Do17, 215, 217, and so on.

 

[Shortround6]

I would be interested to know what the UK and German figures would be. Think of the effort put into Hurricanes, Spifires, Wellingtons and if you take the start as Dec 1941, Stirling's, Halifax's Manchester's/Lancaster's Typhoons and no doubt others. As for the German its a similar story, 109, 190, Ju88 He111 Do17, 215, 217, and so on.

Part of it may be that some of the Japanese "improvements" were of a minor nature. Once the Ki 43 got a two speed supercharger it was essentially frozen. A few minor tweaks?
Some different Ki 61s but mostly just changing the guns around. Some of their bombers show the same thing. The attempts to upgrade the A6M's engine after fitting the two speed supercharger didn't seem to work.
The Spitfire got much more powerful engines. The Wellington got better engines but was pretty much replaced in the primary theater.

I would also note that many of the projects started after 1942 (as in pen went to paper in 1943) failed to reach squadron service in any numbers by 1945 in most air forces.

 

[Glider]

Part of it may be that some of the Japanese "improvements" were of a minor nature. Once the Ki 43 got a two speed supercharger it was essentially frozen. A few minor tweaks?
Some different Ki 61s but mostly just changing the guns around. Some of their bombers show the same thing. The attempts to upgrade the A6M's engine after fitting the two speed supercharger didn't seem to work.
The Spitfire got much more powerful engines. The Wellington got better engines but was pretty much replaced in the primary theater.

I would also note that many of the projects started after 1942 (as in pen went to paper in 1943) failed to reach squadron service in any numbers by 1945 in most air forces.

I agree with your point. If the 'minor tweaks' took little effort then more (in percentage terms) should have been available for new designs. No one would deny that the Spit 14 was a very different animal to the Mk 1 and the same goes for the 109 and 190. Its difficult to think of a similar change to a Japanese aircraft so the percentage of effort spent by the German and British aviation development teams developing existing designs, would be much bigger than 61%

 

[MiTasol]

Part of it may be that some of the Japanese "improvements" were of a minor nature. Once the Ki 43 got a two speed supercharger it was essentially frozen. A few minor tweaks?
Some different Ki 61s but mostly just changing the guns around. Some of their bombers show the same thing. The attempts to upgrade the A6M's engine after fitting the two speed supercharger didn't seem to work.

Part of the problem (a very big part if the German staff in Japan are to be believed) was that no-one wanted to take responsibility for any changes. This is from page 21/22 of German translations of activities in Japanese aircraft production 7 September 1945. Report No. 9-a(50), USSBS Index Section 6 - 国立国会図書館デジタルコレクション

A better translation of the title might be Translations of German activities in Japanese aircraft production

 

[Kevin J]

Part of the problem (a very big part if the German staff in Japan are to be believed) was that no-one wanted to take responsibility for any changes. This is from page 21/22 of German translations of activities in Japanese aircraft production 7 September 1945. Report No. 9-a(50), USSBS Index Section 6 - 国立国会図書館デジタルコレクション

A better translation might be Translations of German activities in Japanese aircraft production

View attachment 565107

This reminds me of working for Fujitsu-ICL in the 1980's.