Japanese Zero vs Spitfire vs FW 190

[nuuumannn]

I have to wonder if the Japanese Military felt that the Zero needed to be replaced?

It appears a viable question, but, yes, the IJN had definitely intended on replacing the A6M, with the A7M Reppu, which should have had a similar timeline as the F6F, but for many seemingly inexplicable reasons it didn't. It's first flight in 1944 was not until after the F6F had already entered service aboard US carriers, two years after the project to replace the A6M was reinitiated in mid 1942 - it had its origins in a requirement laid down in 1940 around the same time as the A6M first entered service, and why was this not progressed with in the mean time to be reinitiated two years later?

I have not read any definitive answer to exactly why the resources were placed into improving the A6M instead of concentrating on getting its replacement into service. From the reading of English texts, which might suffer owing to lack of credible information, the tactical situation the IJN found itself dealing with following the defeat at Midway and the loss of a significant portion of its carrier fleet saw a rise in urgency for land based interceptors and effort went into those, Mitsubishi concentrating on the J2M, whose development began before Japan went to war, and Kawanishi the N1K land based fighters, while the A6M was left to soldier on on carrier decks.

Development of the A7M was protracted, with bombing and a natural disaster contributing to its failure to see production before the end of the war, but these things did not begin to affect the programme until 1944/1945, so what happened beforehand? Was it as simple as a lack of carriers meant that Japan's focus changed to land based interceptors keeping the enemy away from its newly captured territory? It seems a stretch to believe such a simplistic view of a reaction to the strategic situation Japan found itself in, but Mitsubishi's resources did focus on the J2M and improving the A6M, rather than concentrating on pushing the A7M toward service status. One author hints at the fact that Mitsubishi was overworked and under resourced but that doesn't explain the effort stream channeled toward improving the A6M instead of developing the A7M...

 

[tomo pauk]

It seems a stretch to believe such a simplistic view of a reaction to the strategic situation Japan found itself in, but Mitsubishi's resources did focus on the J2M and improving the A6M, rather than concentrating on pushing the A7M toward service status. One author hints at the fact that Mitsubishi was overworked and under resourced but that doesn't explain the effort stream channeled toward improving the A6M instead of developing the A7M...

Why the IJN was not going with Raiden to be designed as, 1st, carrier-borne fighter, is/was a big mistake.
As for the improving the A6M, that was going on on a very sedate tempo.

 

[cherry blossom]

There is a joke that the IJN's main enemy was the IJA but perhaps the effects of the fight between Mitsubishi and Nakajima is underestimated. Mitsubishi always wanted to fit a Mitsubishi engine to the A6M, initially the Zuisei in the A6M1 but from 1942 or earlier the Kinsei, which they finally fitted to the A6M8. Mitsubishi wanted to develop its A20 engine project, which used 18 Kinsei sized cylinders, but had difficulty getting funding after the Navy decided in September 1942 that it would standardize on the Nakajima Homare (Nakajima Chikuhei had been an officer in the Navy). The Army also preferred the A18 using 18 Kasei cylinders which would power the Ki-67. The initial design of the A7M used the A20 (to become the M9K) but had to be changed to use the Homare. However, the Homare 11 did not give the predicted power at altitude and the A7M1 was abandoned. By 1944, the slow development of the A20 had given a reliable engine for the A7M2 but that was much too late.

 

[tomo pauk]

By 1944, the slow development of the A20 had given a reliable engine for the A7M2 but that was much too late.

Any good source that confirms that A20 was a reliable engine by 1944?

 

[cherry blossom]

There were probably vibration problems as I have read that rubber mounting buffers had to be installed in the Ki-83. Goodwin and Starkings "Japanese Aero-Engines" has "… and by late 1944 the few hand-built examples completed by then were running reliably and smoothly." on page 116.

 

[tomo pauk]

There were probably vibration problems as I have read that rubber mounting buffers had to be installed in the Ki-83. Goodwin and Starkings "Japanese Aero-Engines" has "… and by late 1944 the few hand-built examples completed by then were running reliably and smoothly." on page 116.

Thank you for the feedback.
Qualifier 'by late 1944 a few hand-built examples completed by then were running reliably and smoothly' sounds much more like 'by 1945 engine was reliable', rather than 'by 1944 engine was reliable', at least from Japanese military point of view?

 

[nuuumannn]

Engine issues certainly sound like a logical reason behind delay in the project toward 1944/45, but again, why did Mitsubishi bring the project to a halt in 1940, then re-instate it in 1942? Did the government/military halt development? That seems the most logical reason, I'm sure Horikoshi and Co would have been following orders. Another example of the lack of strategic foresight the Japanese military regime displayed.

 

[tomo pauk]

Engine issues certainly sound like a logical reason behind delay in the project toward 1944/45, but again, why did Mitsubishi bring the project to a halt in 1940, then re-instate it in 1942? Did the government/military halt development? That seems the most logical reason, I'm sure Horikoshi and Co would have been following orders. Another example of the lack of strategic foresight the Japanese military regime displayed.

IJN was calling the shots, and they made mistake (doh). Especially it is a glaring one, when we know that J2M was in the works with 1400 HP engine by 1941. By what time Japanese fully knew that Germans were making a fighter around 1600 HP engine, that in return meant the British and Americans are at least there.

 

[GregP]

The J2M was an IJN aircraft, but was NOT a carrier aircraft. Not saying anything, just trying to be clear that the J2M was land-based.

 

[nuuumannn]

The J2M was an IJN aircraft, but was NOT a carrier aircraft. Not saying anything, just trying to be clear that the J2M was land-based.

That was made pretty clear earlier when I stated that the IJN concentrated development of land based interceptors, such as the J2M and N1K series.

 

[GregP]

Sorry, nuuumannn, didn't read the earlier post. Just looked at using Raiden as a carrier aircraft.

Mea culpa. Cheers.

 

[Shortround6]

Just an idea but the the Japanese engine development was a bit behind the times.
The aircraft development times were also behind the curve/s.
As by the A6M the first prototype flew in April 1939 but the first satisfactory combat examples weren't built until May of 1941.

In 1939 (or earlier) to 1941/42 some other aircraft chose the route of small wing and high wind loading to get the max performance from smaller engines.

For the Japanese the "idea" of a interceptor may have also made sense because they had no (or little) radar coverage.

Once starting it on that path it is hard to stop.

 

[tomo pauk]

Just an idea but the the Japanese engine development was a bit behind the times.
The aircraft development times were also behind the curve/s.

We can note that Mitsubishi designed the Zero around the least powerful of their engines. I'll agree that Japanese engines were not the greatest in a time period we are taking a look, there was still an opportunity to choose a more powerful engine as a starting point, with Mitsubishi already having two of those in the pipeline at the time.

In 1939 (or earlier) to 1941/42 some other aircraft chose the route of small wing and high wind loading to get the max performance from smaller engines.

For the Japanese the "idea" of a interceptor may have also made sense because they had no (or little) radar coverage.

Once starting it on that path it is hard to stop.

Capable carrier-borne interceptors were even more needed, since their fail means that the CV is likely badly damaged by an air attack, or even lost, with all aircraft that depend on it. An air base that gets bombed is in function another day. Air base can be established in mater or days need be, aircraft carrier less so.
A CV-borne interceptor can be quickly transformed into a land-based interceptor. Opposite is not true.

 

[Clayton Magnet]

an opportunity to choose a more powerful engine as a starting point, with Mitsubishi already having two of those in the pipeline at the time.

That has always baffled me, why Mitsubishi chose a rival firm's engine instead of their own Kinsei. Perhaps the latter wasn't immediately available for use in the prototypes?

 

[tomo pauk]

That has always baffled me, why Mitsubishi chose a rival firm's engine instead of their own Kinsei. Perhaps the latter wasn't immediately available for use in the prototypes?

IIRC it was IJN that wanted something better than Zuisei of the time (840 HP vs. 950 HP for the Sakae); Navy considered the Kinsei as not as fuel-efficient as the smaller Sakae?

Zuisei was quickly (talk 1941) improved to the power-vs-altitude levels of contemporary Sakae (no wonder, the two were as close in construction, displacement and fuel used as possible) and kept as such until 1944?

 

[nuuumannn]

Mea culpa. Cheers.

No problem, Greg.

That has always baffled me, why Mitsubishi chose a rival firm's engine instead of their own Kinsei. Perhaps the latter wasn't immediately available for use in the prototypes?

We can note that Mitsubishi designed the Zero around the least powerful of their engines. I'll agree that Japanese engines were not the greatest in a time period we are taking a look, there was still an opportunity to choose a more powerful engine as a starting point, with Mitsubishi already having two of those in the pipeline at the time.

I don't think it was Mitsubishi's choice to accept either the Sakai or the Zuisei. Horikoshi/Mitsubishi didn't favour the Sakai because it was made by Nakajima, Horikoshi wanted to use the Kinsei, which was more powerful than both engines, but the navy insisted on the Zuisei, which worried Horikoshi because of comparable aircraft being built overseas were powered by engines with greater power output, and so the Zuisei was installed on the first two prototypes only. Following them, the Sakai was installed in the third prototype, most likely because of the Zuisei's low power output; the Sakai established the production layout and was most likely also a navy decision, given Horikoshi's desire not to fit a rival firm's engine.

 

[GregP]

You'll notice that Horikoshi's NEXT aircraft, the J2M Raiden, had a more powerful engine, more on par with Allied rivals. It also had self-sealing tanks and pilot armor.

 

[cherry blossom]

I have been looking at Akira Yoshimura's Zero Fighter to try to understand how the Zero was designed. There is a problem that Yoshimura was a novelist rather than a historian and doesn't believe in footnotes but he probably spoke to people who may have remembered a few details and he may have recorded them correctly. Page 30 has:

Under these circumstances, Horikoshi had a choice of two types of air-cooled radial engines, the Zuisei (Star of Fortune) or Kinsei (Venus). Mitsubishi made both. Ideally, Horikoshi wanted something between these two. The Kinsei delivered 1,100 horsepower at 4,200 metres, the Zuisei 875 horsepower at 3,600 metres. However, he chose the smaller Zuisei to reduce weight. Even so, it was estimated that the Zuisei would make the new fighter 50 percent heavier than the Type 96 fighter. However, installing the Kinsei would have produced a much greater increase, 70 to 80 percent. Horikoshi felt this would be unacceptable to pilots.

The "pilots" above may refer to Lieutenant-Commander Genda who was present in a meeting on 7th January 1938 and argued fiercely for manoeuvrability with Lieutenant-Commander Shibata Takeo who insisted on speed. However, perhaps we should note that Japan had a number of small aircraft carriers such as Ryūjō and was building others such as Zuiho and Shoho whilst planning to convert several liners. The USN kept Wildcat versions in production until 1945 and planned to replace them with the Bearcat on CVEs whilst using the F6F and F4U from larger carriers.

 

[P-39 Expert]

The test in question was concluded on January 26, 1943. That's almost a year before the P-38 starting flying long range escort missions over Germany. In fact the tests were being conducted in the same time frame that the time the P-38 was entering combat in the Pacific and North Africa. Regardless of who decided not to improve the heating there was plenty of time to implement a fix before the P-38J began having issues over Germany.


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I would certainly agree that the P-38F was superior to its American contemporaries.

Read on down to item 4.B. RECOMMENDATIONS: "Suitable means of maintaining cockpit heat at altitude be installed. (Cockpit heater on P-39N is best seen to date)."

They always test the newer models against the P-39D-1 which is the heaviest and lowest powered model produced in 1942.

 

[FLYBOYJ]

They always test the newer models against the P-39D-1 which is the heaviest and lowest powered model produced in 1942.