Japanese Design Philosophy

[GrauGeist]

Japan's immature industrial capabilities?

Seriously?

Nakajima had been producing engines and aircraft since 1918.

Mitsubishi, which had been producing heavy industry products since the late 1800's, started manufacturing engines in the 1920's.

Kawasaki was involved in heavy industry since the late 1800's.

Hitachi and Aichi started in the early 1900's.

The list goes on, but to assume that the Japanese were newcomers to the game is completely ridiculous.

 

[AerialTorpedoDude69]

Japan's immature industrial capabilities?

Seriously?

Nakajima had been producing engines and aircraft since 1918.

Mitsubishi, which had been producing heavy industry products since the late 1800's, started manufacturing engines in the 1920's.

Kawasaki was involved in heavy industry since the late 1800's.

Hitachi and Aichi started in the early 1900's.

The list goes on, but to assume that the Japanese were newcomers to the game is completely ridiculous.

Yes, I did mean that, but sorry for sounding dismissive. It's true that early Japanese industry relied more heavily on manpower than industrial equipment. Were they classified as an industrial power? Yes. Did their products require a lot of man hours?

Japanese aircraft needed more manhours per aircraft than any other power during the war, which is because of their industrial strategy which leveraged low cost labor to produce products for export. This is known as export-oriented industrialization.

CORRECTION: Japan had low labor costs not an export-oriented industrialization policy. Its strategy for catching up with Western economies was led by state-owned production houses which were eventually privatized and conglomerated into large corporations known as Zaibatsu. Their prewar industrial policy was known as the "infant industry argument" in which the state subsidizes early industries. These early industries eventually became major exporters but the trade regime of the era was dominated by high tariffs and other barriers to international trade.

 

[Shinpachi]

You had better discuss why the US was/is so superior IMO

 

[tomo pauk]

tomo pauk I think the Kinsei 50 was capable of 3,000 RPMs, according to this post.

Over-speed limit for dives, noted as allowed just for 30 seconds? Similar for 3180 rpm for the V-1650-1 limit, or 3100 rpm dive limit for the R-2800-34W? 3060 rpm dive limit for the R-2800-10.

 

[ThomasP]

Hey AerialTorpedoDude69,

I think you are mistaken about Japan's pre-war economy being based on export-oriented industrialization. From what I have read, prior to WWII their economic growth and industrialization was primarily investment led by their zaibatsu, and to a lesser degree by government agencies, beginning during the post-Meiji Restoration period. This was also true after the war for a decade or two during the reorganization and rebuilding of their corporations, and industrial base. I think you could accurately say they engaged in a significant amount of export-oriented industrialization for a couple of decades after the 1960s, when Japan began selling progressively higher quality goods to overseas markets - but at lower prices than the target country's markets could match. But after a couple decades of this they went back to an investment led economy and industrialization, and are still following that strategy.

NOTE I am not an economist or particularly well educated in economic systems, so we might be using terms differently here, and therefore what I am saying above may not be technically true in the science of economics terminology. And I could be wrong.

 

[GrauGeist]

Japanese aircraft needed more manhours per aircraft than any other power during the war,

May want to run Japanese production man-hours against Italian production man-hours.

 

[GrauGeist]

Hey AerialTorpedoDude69,

I think you are mistaken about Japan's pre-war economy being based on export-oriented industrialization. From what I have read, prior to WWII their economic growth and industrialization was primarily investment led by their zaibatsu, and to a lesser degree by government agencies, beginning during the post-Meiji Restoration period. This was also true after the war for a decade or two during the reorganization and rebuilding of their corporations, and industrial base. I think you could accurately say they engaged in a significant amount of export-oriented industrialization for a couple of decades after the 1960s, when Japan began selling progressively higher quality goods to overseas markets - but at lower prices than the target country's markets could match. But after a couple decades of this they went back to an investment led economy and industrialization, and are still following that strategy.

NOTE I am not an economist or particularly well educated in economic systems, so we might be using terms differently here, and therefore what I am saying above may not be technically true in the science of economics terminology. And I could be wrong.

Considering that Japan's industrial capacity was severely crippled by war's end, it would take considerable investment and rebuilding in order to get any significant production back online.

Same can be said for Germany.

To add to this, before any industrial base could be realized, the nation's infrastructure had to be repaired.

 

[Shortround6]

The US perception of Japanese industry was skewed by the importation of large amounts of cheap Japanese "tin" toys in the period between WW I and WW II.
Japan is slightly smaller than the state of California in land area. Kind of shows the Japanese problem with the perception of US size/power.

But the Japanese had a sizable ship building industry, 3-4 times the iron/steel industry of Italy and other industries that were advanced even if not on the scale of the US in size.

Every aircraft engine or aircraft design is collection of compromises. The problem is that many times the user doesn't know if they tipped things too far one way or another in the design process until something is in production or in use/combat.

The US was enough bigger that many of it's mistakes could be swept under the rug. And then a bigger, thicker rug laid over the first one. And another one added on top of that.

Continental XI-1430 Aircraft Engine

Developed from the Continental O-1430, the inverted Vee XI-1430 was a compact, high-performance aircraft engine. Although 2,100 hp was achieved, the engine was troublesome and too late for WWII.

oldmachinepress.com

And that is not the full story as other programs were under-funded while the fair-haired boy soaked up funds/resources for years after it should have been set adrift.
There are a few other major screw ups just in engine development. Or more than a few, like 5-7 depending on count/combinations.

Allison seemed to have been viewed as a temporary stopgap/fill-in and not really a war winning engine in it's own right. At least most of the time.

Japan may have forgotten a quote from the 1600s.
God is on the side of big battalions.

It may not always work but you need something to even up the odds.

Depending on small engines seems like a poor policy choice.

 

[AerialTorpedoDude69]

I think you could accurately say they engaged in a significant amount of export-oriented industrialization for a couple of decades after the 1960s, when Japan began selling progressively higher quality goods to overseas markets - but at lower prices than the target country's markets could match. But after a couple decades of this they went back to an investment led economy and industrialization, and are still following that strategy.

Thank you for the correction! There's a lot that I should learn or refresh myself on about pre-war trade before writing about it.

Here's what I remember and/or just read: Japan first undervalued the Yen during its early industrialization period and exported vast quantities of gold. However it responded to the great depression by overvaluing the yen. At the time of the war, they definitely did not have an export oriented trade strategy. I just found out that Japan ran a trade deficit from 1929 to 1939 and that it rarely ran a trade surplus prewar. It essentially used raw materials and craft products exports to jump start its government run production houses. But these production houses were privatized and conglomerated into the Zaibatsu, as you wrote.

Going over the research data, I do not know why Japan's labor costs were much lower than in the West. It might have to do with labor controls, use of slave labor, and wage controls. But the fact remains, their aircraft had a much higher amount of manhours invested in them any other nations and that's because of a heavy amount of hand finishing by skilled machinists.

May want to run Japanese production man-hours against Italian production man-hours.

I don't know, but I remember reading here that Germany wanted to acquire some of Italy's midwar designs because they offered lower production costs. But my guess is that Italy, like Britain, used a lot of machinists in its production processes. However, as far as I'm aware, Japanese aircraft throughout the war used a higher proportion of skilled machinists to produce aircraft than any other nation.

My point was that Japanese engineering was excellent and about equal to Western engineering standards. Their industry, due to economies of scale, a lack of centralization, and a lack of raw resources, was not up to Western standards. Germany's industry was much more advanced and even it was not up to US standards.

This video clip summarizes what happened.

 

[Shortround6]

from an old post up dated.

engine type.....................cylinders.....cyl.size............eng diameter........weight..........displacement................rpm

Mitsubishi Zuisei...............14..............140/130.............1118mm..............540kg............28L (1708 ci?)............2450/2700
Nakajima Sakae (early)...14..............130/150.............1150mm..............530kg............27.9L (1702 ci?).............2500
Nakajima Sakae (late).....14..............130/150.............1150mm..............590kg............27.9L (1702 ci?).............2800
Mitsubishi Kinsei...............14..............140/150.............1218mm..............545kg...........32.3L (1971 ci......?)...2300/2600
Nakajimi Ha-41..................14..............146/150............1260mm..............630kg............37.5L (2287 cu?)............2500
Nakajima Ha-109..............14..............146/150............1260mm..............720kg.............37.5L (2287 cu?)............2650
Mitsubishi Kasei.................14..............150/170............1340mm..............780kg.............42L ( 2567ci ?).........2350/2600
Nakajima Mamori.............14...............155/170............1380mm..............870kg............49L ( 2989ci ?)...............2600
Nakajima Homare............18................130/150............1180mm..............835kg............35.8L (2183ci ?).........2900/3000
Mitsubishi Ha-104...........18.................150/170...........1372 mm.............1140 kg........54.1L (3301 ci).................2450

I would note that the Mamori was not exactly a success and about 200 were built. Also when the A6M8 was built with the Kinsei engine the cowl gun/s were deleted.
The Nakajima Ha-41 and Mitsubishi Kasei were originally bomber engines.
Weights for Japanese engines can vary depending on model.

Allied/European engines for comparison

Wright R-1820..................9...........155.6/174.6........1400mm.............442-617kg............29.9L..............2200/2500
P W R-1830.....................14............140/140..............1221mm..............662kg*....................30L................2600/2700
Wright R-2600...............14.............155.6/160.3......1377mm..............886kg.....................42.7L..............2400/2500
P W R-2800.....................18.............146/152.............1326mm............1043kg.....................45.9L..............2600/2700
Taurus................................14...............127/143............1173mm..............590kg.....................25.4L...................3100
G-R 14N...........................14.............146/165.............1290mm...............750kg......................38.7L.................2400(?)
Hercules...........................14..............146/165................1321mm...........762kg......................38.7....................2800
Fiat A.74...........................14..............140/145...............1195mm............570kg......................31.2L.................2550(?)
Piaggio P.XI....................14...............146/165...............1328mm............650kg.....................38.7L..................2200

All of these are early (1941 or before) versions. Some of the infromation was what was being released to the public. After war specs may differ.
The Soviet M-88 was a cousin of the G-R 14/Piaggio P.XI and there were attempts in France and Italy to stretch it to 18 cylinders.
P&W had given up on the R-1535 (25.2 liter) engine in 1939 except for completing existing contracts.
The Japanese don't seem to really be pushing high rpm (some of the European engines were using 2 main bearing crankshafts) by very much except for the Homare and not by a lot.
The Japanese do tend to favor small diameter. I am not sure it payed off in the end.

 

[tomo pauk]

Mitsubishi Ha-104...........18.................150/170...........1372 mm.............1140 kg........54.1L (3301 ci).................2450

Ha 104 was just under 950 kg.

The Nakajima Ha-41 and Mitsubishi Kasei were originally bomber engines.

So was the Merlin

 

[Shortround6]

My point was that Japanese engineering was excellent and about equal to Western engineering standards. Their industry, due to economies of scale, a lack of centralization, and a lack of raw resources, was not up to Western standards. Germany's industry was much more advanced and even it was not up to Allied standards.

There are two different engineering standards going on here. Japanese and Germans may have been able to design stuff. They had trouble figuring out how to manufacture the stuff.
You need large numbers of engineers that just look at parts/blue prints and figure out how to make the stuff faster and cheaper. Or engineers that are designing machines that can do more operations with less input from operators.
You can make a lot things with simple lathes. You just can't make things fast. Turret lathes speed up production.
Machines that were semi-automated speed things up even more or require fewer good/experienced machinists.
There were machines that were operated by a series of rods with adjustable stops and micro switches. As the tool advanced/traveled to the end of it's preset travel it would hit the micro switch and the machine would move the cutter away and then go to the next operation, like return to start and make another pass or index the tool head to bring another cutter into line and then make a pass with the new tool. Not all passes had to make the same travel so steps could be cut.

It was this ability to manufacture the new tools and equipment that allowed for higher production with less manhours and less skilled workers that really made a difference.
Things like the centrifugal casting table making R-2800 cylinders (6 or 8 molds per table) spinning the molds to get rid of air and producing the 6 or 8 castings in one batch.
But some of these machines were many tons and took up a lot of space. Like the famous grinders sent to help with Sabre production.
Even the US could not make unlimited machine tools. But they were in better shape than anybody else.
My Grandfather worked in a 4 man shop making gyroscope parts for Norden. Using machine tools driven by overhead belts, they were slow but skilled.
The US used both approaches or rather used resources to good advantage (I am sure there were screwups) but the US often had a lot of machine tools supporting various industries just do to size. It could take 3-4 days (or longer) to get parts shipped by rail from a distant factory (forget driving in the 1920s-30s) and the there was a lot of local work for good machinists.

 

[Shortround6]

So was the Merlin

only counting the Battle

I don't know when the distinction between fighter and bomber engines came about. Maybe a left over from WW I although there was some cross over then.
It may have come about because of the "maneuverability mafia" who decried large heavy engines in the nose of the airplane and preferred flying 20-30mph slower?

 

[tomo pauk]

only counting the Battle

Only counting the Ki-49 for the bomber role of the Ha 41

I don't know when the distinction between fighter and bomber engines came about. Maybe a left over from WW I although there was some cross over then.
It may have come about because of the "maneuverability mafia" who decried large heavy engines in the nose of the airplane and preferred flying 20-30mph slower?

To me, the distinction between 'bomber' and 'fighter' engine is very subjective, so I've never gave it much of importance.

 

[bf109xxl]

It may have come about because of the "maneuverability mafia" who decried large heavy engines in the nose of the airplane and preferred flying 20-30mph slower?

Well, they had some reason for that opinion. I know of at least one very expressive example (as well as a couple of less expressive ones) of the extremely unsuccessful use of a large heavy "bomber" engine in a fighter.
Piston fighters seem to be more "sensitive" to specific parameters (e.g. engine weight per hp). Of course, the classification of engines into bomber and fighter can be considered as pure convention. However, there were engines that never succeeded on fighters.
Though in the same design bureau there was an opposite example, but already after the war and with jet engines....

 

[JoblinTheGoblin]

It does appear to be the case, for the most part, that Japanese aircraft have larger wing areas that would incur more drag. I've seen this and other similar design choices attributed to a sort of 'manoeuvrability mafia', at least in the IJA, that overruled more technically advanced designs like the Ki-11 (Japanese Peashooter, essentially), Ki-12 and Ki-28 in favour of slower but more manoeuvrable designs like the Ki-10 and Ki-27. The Ki-11 at least appeared to suffer from a slower rate of climb than the Ki-10, but was otherwise more efficient in terms of level speed at altitude. Finding data online for the Ki-12, and for any early-war (or even late-war, as I will get into later) Japanese prototype is not trivial, but it apparently possessed a 20mm cannon, and in addition to the usual 7.7mm pair? The Ki-12 was also Western-designed, requiring a Western liquid-cooled engine like the later Ki-28, and the IJA understandably did not want to rely on foreign licensed engines. The Ki-28 was, though another less manoeuvrable design, faster and could climb higher than most variants of the Ki-27, if any ever did exceed it in these metrics Another issue arises then with the Ki-18, superior to the Ki-10 in nearly all aspects save perhaps turning times or low-speed roll rates. It was a proposal to the IJA derived from an IJN design, the A5M. No need to say much more than that. Supposedly, though I've long forgotten the source of this information, a main concern of the "manoeuvrability mafia" was countering biplane designs that were more common in nearby China, and if that was the case, perhaps a more powerful China (say, earlier unification under the Zhili clique?) would have changed their minds, if slightly. This type of opponent may have contributed to a preference for manouevrability amongst the pilots as well, though I'm not entirely sure. There's some bits of information here and there on this forum that pilots were anxious about the manouevrability of the Ki-43 when it was initially put into production and how even as speed became a more serious issue later in the war, manoeuvrability was apparently still important for Ki-43 pilots when it came to surviving BnZ opponents, something the Ki-84, from first-hand accounts on both sides fast enough to avoid the P-51 / F4U(?) (at low-mid altitudes?), was claimed to have been more vulnerable to thanks to its lesser manoeuvrability.

The main issue with assessing late-war Japanese aircraft performance is a lack of detailed data, especially power curves and the like. For instance, the level speeds of aircraft like the Ki-87 and the aforementioned Ki-83 are given at altitudes above 10000m (>32000ft), and vary between ~680kph (422mph) and <710kph (441mph). Worse, I've seen a slower figure outside of that range given for the Ki-83 at around half the altitude (supercharger, maybe, if the figure's to be believed). I can't say much more than this right now.

 

[GrauGeist]

The Ki-11 was also Western-designed, requiring a Western liquid-cooled engine like the later Ki-28, and the IJA understandably did not want to rely on foreign licensed engines.

The Nakajima KI-11 had an air-cooled Ha-1 radial engine.

 

[JoblinTheGoblin]

The Nakajima KI-11 had an air-cooled Ha-1 radial engine.

I meant the Ki-12. Silly mistake.

 

[ThomasP]

re the Japanese early-war emphasis on maneuverability

I have posted this before:

Just pre-war, the prototype XF4F (monoplane) and the XF2A were test flown against the F3F in mock dogfights. There is no question that the F4F and F2A were faster (both could do over 300 mph vs the F3F at ~255 mph) and hence could force or avoid a fight if whey wanted to when aware of the enemy (at least for the most part), but it was found that the only way for the monoplanes to reliably survive the fight was to leave the area after the initial attack.

Running away after the first attack was often not conducive to accomplishing the mission.

 

[Shortround6]

Running away after the first attack was often not conducive to accomplishing the mission.

Disengaging to re-engage after an advantage has been gained (regained?) may not actually being running away. Depends on the tactical situation at the time.
Bomber escort depends on how far away (and time of estimated intercept by the attacking fighters) the forces are.
Intercepting attacking bombers (with escorts) depends again on distance/time to bomber target. Can the mono-planes re-engage before the drop zone is reached.

And so on.
It also depends on exactly which planes we are comparing.

Just for the JAAF there seem to be two schools of thought which is fairly common to the military aviation around the world.
We also have to look back to see/understand the path taken or not taken.

Nakajima Type 91 fighter, 1927 requirement, first flown in 1931, entered service (slowly?) in 1931, last built 1934.
450 built.

Wing area 220sqft
gross weight 1530kg(3373lbs)
wing laoding 15.7lbs/sq/ft
engine 450-520hp
2 7.7mm machine guns (Vickers)

top speed 190mph
endurance 2 hours
ceiling 30,000ft
time to climb 4 minutes to 3000 meters.

these were paired with the Type 92 by Kawasaki

First flown 1930 and introduced in 1932, 385 built.

Wing area 285 sqft
gross weight 1700kg(3747lbs)
wing loading 14.5lbs/sq/ft
engine 630hp
2 7.7mm machine guns (Vickers)

top speed 199mph
endurance range 528 miles
ceiling ???
time to climb ????

Unstable in landing and take-off (not stated if on the ground or at low speed in the air)
Difficult to maintain, especially in cold weather (no anti freeze for one thing, you have to drain the water to keep it from freezing)

These were what were being replaced by the requirement that lead to the Ki-10 biplane and the Ki-11 monoplane.
In the next post.