Japanese doing things different in for before and during ww2?

[Macandy]

Bringing us back on topic but still related, the Japanese were deficient in both mechanics and supply chain. The Allies would pull parts off a plane to keep another flying, but the Japanese would just leave any disabled plane sitting there until new parts arrived, or just scrap the plane for want of parts and mechanics to install them.

Japanese production relied on many hundreds of 'mom and pop' manufacturing shops around the main production plant.
Many photos of firebombed Japanese cities show lots of small pillar drills, fly press's and toggle presses in the ruins, these were in back yard workshops making small parts.
Once the US started fire bombing the cities, all these parts manufacturers went out of business - permanently.

 

[Shortround6]

Britain have had 2 major and several minor engine companies, with Napier and A-S in-between?

I was trying to simply things. The companies making training/light plane engines are unlikely to design/build high power combat engines. A-S had already fallen through the cracks into the basement. 1st production use of a 2 speed supercharger but the planes using it are banned from overwater flights in peacetime due to reliability. Do you really want them designing your next generation of combat engines without multiple back ups? Same for the other countries.
The 1938 Janes lists over 22 US companies making (or recently having made) aircraft engines. However once you start looking at the ones that made engines of over 500hp the number got a lot fewer.

I have nothing against the DB 601A in 1939-40, even in 1941. However, thinking that in 1942 a 1100-1200 HP V12 will offer an edge over a 1300-1500 HP 14 cyl radial the Japanese companies have experience with, both in design, debugging and production (and with 1500-2000 HP designs in the pipeline) requires a lot of cool aid.
There was no such experience in designing and debugging of V12s in Japan.

The cool aid in when people thought that just the design (blue prints) for an engine were enough, and that is before you start modifying anything. Any changes in metallurgy (alloys or heat treatment) can set things back considerably. The Japanese did have a little experience with V-12s but it was dealing with 1920s engines. Kawasaki stuck a supercharger on the BMW V-12 and got it to work but that wasn't that much of a stretch.

Did Homare really fell on it's face, or the other factors were to blame, like the octan value of Japanese fuel by 1945, and state of Japasese support industry and maintenance?

The Homare promised an an awful lot and failed to deliver.
Let's build an engine under 80% of the displacement of an R-2800. and over 400lbs lighter and use crappier fuel (but we use water injection) but we will get just about the same amount of power because we are so clever?
Or look at it another way, take the Cylinders of a Sakae engine (that was not even making 85hp per cylinder in development models of the Sakae) and use them in an 18 cylinder engine (that won't make over 1550hp) and 'tweak" it to get another 300hp (just to get into the 1800hp area).
Where was the 20% increase in power per cylinder supposed to come from? And more importantly, where was the heat supposed to go?
Increasing the RPM by 7% isn't going to cut it. Using more boost and water injection helps more boost requires more power to made in the cylinders which increases heat problems.
The Homare was not simple solution like the Kasei (think of that like an R-2600).

It was attempt to build one of the highest output aircooled engines engines ever built on the basis of displacement and use low octane fuel while doing it. (an R-2800 making 2336hp would have the power per liter as an 1825hp Homare, a 2000hp Homare is making the same power liter as an 2560hp R-2800).
Now note that the R-2800 was using two stage supercharging (either mechanical or turbo), 100/130 fuel, water injection and intercoolers AND weighed hundreds of pounds more.

Something is a a bit off in the goals for the Homare, even if you are going to accept a lower overhaul life.

 

[tomo pauk]

The Homare promised an an awful lot and failed to deliver.

How much the Homare promised?

 

[Shortround6]

How much the Homare promised?

I don't know what was promised when but they planned on using it for perhaps the widest selection of aircraft for the both the Army and Navy of any engine the Japanese used in WW II.
Some of the prototype aircraft were flying at the end of 1942 with Homare engines rated at 1800hp for take-off. What they gave at high altitude my be a bit different.
They offered the small diameter, always attractive on the surface but perhaps less so in practice. They were also offering the low weight, within 30-50kg of the Kasei engine.

 

[tomo pauk]

I don't know what was promised when but they planned on using it for perhaps the widest selection of aircraft for the both the Army and Navy of any engine the Japanese used in WW II.

How much the Nakajima promised with Homare power-wise is a whole another ball game vs. how much Nakajima promised with production.

Some of the prototype aircraft were flying at the end of 1942 with Homare engines rated at 1800hp for take-off. What they gave at high altitude my be a bit different.

Altitude power will certainly be different, namely lower - same as with the other engines with 1-stage 2-speed superchargers of the time.

They offered the small diameter, always attractive on the surface but perhaps less so in practice. They were also offering the low weight, within 30-50kg of the Kasei engine.

I'd chalk that under 'delivered' category, not 'promised'

Let's build an engine under 80% of the displacement of an R-2800. and over 400lbs lighter and use crappier fuel (but we use water injection) but we will get just about the same amount of power because we are so clever?
Or look at it another way, take the Cylinders of a Sakae engine (that was not even making 85hp per cylinder in development models of the Sakae) and use them in an 18 cylinder engine (that won't make over 1550hp) and 'tweak" it to get another 300hp (just to get into the 1800hp area).

Seems like it worked, until it didn't, due to the fuel octane dropping closer to 87 oct and the material and manpower support to the engine dwindled. Homare was not just an 18 cylinder version of Sakae.
We can recall that Americans have no problems with Homare during the tests, and that not every American engine was exactly bed of roses, even in 1944.

A bit about the power/displacement and power/weight values of mid- and late-war Japanese engines.
Kinsei 62 was making above 1600 HP with 91 oct fuel and ADI, at least by US data and Soviet tests. 1600/1970= 0.81 HP/cu in, and 1600/1340= 1.194 HP/lb.
Kinsei 20 series - 1880 HP per US data on 91oct + ADI. 1880/2570 =0.73 HP/cu in, 1880/1680 lb (versions with 'normal0 reduction gear, no fan etc.) = 1.12 HP/lb.
Homare 12 - 1860 HP per US/TAIC data, on 91 oct + ADI. 1860/2185 = 0.85 HP/cu in, 1860/1830 = 1.02 HP/lb.
Homare 2 - 2040 HP per the report on the engine on 91 + ADI. 2040/2185 = 0.93 HP cu in, 2040/1830 (Nakajima data gives the same weight for the two types, US data is sketchy) = 1.115 HP/lb.

Unlike the Japanses 'legacy' engines, Homare was with the forged steel crankcase, that is ought to improve the odds of engine surviving the greater RPM and power. It seems perhaps a bit stretched out when compared with American engines, but it it's power/displacement and power/weight values are merely an evolution when compared with older Japanese engines.

 

[Shortround6]

The smaller cylinders mean you get more cylinder wall area for the volume and the smaller cylinders means a bit shorter distance between the piston center and the cylinder walls for cooling. But the majority of cooling is done with the cylinder head/s. The bigger American cylinders are a bit harder to cool but the Americans also spent a lot more effort on cooling fins. And the manufacturing techniques to make the cylinders and heads at rates of over 1000 heads/cylinders per day.

Some of the American engines were certainly more a bed of thorns than of roses.
Which makes it harder to understand how the Japanese achieved the levels they did.
R-2600 BB.....1900hp at 2800rpm/48.5 in boost (1232mm/472mm boost) 1900/2600= 0.73 HP/cu in, and 1900/2045= 0.92 HP/LB 100/130 fuel no water injection.
3rd major change of crankcase from 1600hp version and a major change in the fins, rolled in sheet metal vs machined fins.
These were not trouble free in all installations.

The Wright R-3350 used the same size cylinders, just 18 instead of 14 and we all know how that worked out
R-3350 BA.....2200hp at 2800rpm/48.0 in boost (1219mm/459mm boost) 2200/33500= 0.66 HP/cu in, and 2200/2650= 0.83 HP/LB 100/130 fuel no water injection.
Engine with turbos and single speed supercharger was rated at 2600hp on 100/130 fuel plus ADI. (post war?)
Engine used steel crankcase. Wright was on their 4th or 5th steel crankcase by this time (maybe more) counting the R-1820 engines.

The changes at the lower end of the fuel scale are not small
87 oct = 68.29 PN
88 oct = 70.00 PN
89 oct = 71.80 PN
90 oct = 73.68 PN
91 oct = 75.68 PN
92 oct = 77.78 PN
93 oct = 80.00 PN
94 oct = 82.35 PN
95 oct = 84.85 PN
96 oct = 87.50 PN
97 oct = 90.32 PN
98 oct = 93.33 PN
99 oct = 96.55 PN
100 oct =100.0 PN

evolution only takes you so far, Both P & W and Wright had to use new materials (forged steel crank cases for Wright, P & W stayed with forged aluminum even on the R-4360) and new methods even if they used the same size cylinders.

 

[spicmart]

The Homare was very light with only 810 kg. Did that contribute to its unreliability? The Griffon 65 generated 2230 hp with 150 octane fuel.
How much would one expect for the Homare?

 

[WAFU]

Let's say that Japanese take a good and hard look at what Europeans (and especially Germans) were doing with regard to not just aircraft-related technology, but also with regard to mass production of military hardware. Japanese start their 'investigation' once the Tripartite pact is signed, 27th September 1940, and start employing the knowledge gained by some time Spring of 1941 where possible.

To get the ball rolling, I'd propose a ruthless reduction of aircraft types slated for series production, ASAP, along with requirement for protection for crew and fuel tanks for any new A/C design.

edit: time of interest is now from 1937 on; thread is about IJA and IJN military aircraft and whatever is related to that

Fundamental problem?

The Japanese Navy and Japanese Army had their own, completely separate air arms and hated each other more than they hated any enemies

 

[mack8]

One of the things they should have done is to scrap the idea of twin engine fighters, either for IJNAF or IJAAF, Japan simply cannot afford that. They were subpar anyway. So instead of 470 J1Ns have 1000 extra A6Ms, and instead of 1700 Ki-45 and 200 Ki-102 have almost 4000(!) Ki-61s with Ha-112 radial engines of course, or at least initially more Ki-43s until the radial Ki-61 is ready.

Also IJAAF were really picky, Ki-43 prototype flew before the Zero but it was not accepted into production until spring 1941 until they put the buterfly flaps on it, whereas the Zero was in production already in middle of 1940. So get the Ki-43 in production asap as soon as the airframe was redesigned (late 1939), so it gets delivered to units from 1940. Oh and reinforce and/or shorten those wings (same with Zero) so it does not break in the air during high speed dives.

In OTL they kept building Ki-27s until late 1942 which was ridiculous.

And about the Homare, imo it would have been a fantastic engine IF Japan had access to 100 octane fuel, quality lubricants and quality materials, neither of which they had unfortunately. But it and the MK9A would have been really top class radials, unrivalled in their combination of small diameter/size and HP/litre ratio.

 

[mack8]

As to the IJNAF fighters, yeah the J2M has to go even if i quite like it, a low wing Shiden being the land based fighter, either with a Kasei or a Homare when that becomes available. So Mitsubishi must build the A7M in 1942, problem being with what engine, as i think the Kasei is simply not powerful enough for it. Which gets me to my idea of an ATL 18 cylinder Mamoru that i like to suggest. This is a 146 x 160 engine of 48 litres, a pre Ha-219 if you like, slightly larger than the R-2800.

It's either that or having to make the A7M smaller, as it was a huge beast, something the size of the Sea Fury would be more preferable, so at least the existing engines could power it.

 

[hobbes154]

I guess this thread has gone quiet for a reason, but attempting a summary and a few comments:

Rationalising production (fewer types) and training (a greater number of less elite pilots) seems obvious if not much fun.

Can you improve the engines? 18-cylinder radials are hard. Everyone was trying but only the Americans really got a lot of use out of them during WW2. If you're stuck with 14-cylinder the Kasei is pretty good. The Kinsei and Ha109 are not bad but a little small. Possibly some rationalisation here also - too many small engines which sucked up resources but were just not powerful enough by mid war. (Like Bristol - just focus on the damn Hercules and Centaurus!) The Mamoru might have been good if they could make it reliable.

2-stage superchargers? If you want to intercept B-29s you need altitude performance and they were trying but not very successfully (like the Germans). Again, this is hard. Were they missing anything obvious?

Airframes? I don't think they did badly given the engines they were using. The A6M2 in particular is incredible for only 950hp. Could use a bit of tweaking in favour of high over slow speed manoeuvrability, but they were onto that pretty quickly. Probably the A7M was too ambitious a successor, they needed an intermediate with a 1500+hp 14-cyl rather than a 2000+hp 18-cyl (I don't know if the A6M8 would have worked out). The Ki-44 is also good but not a carrier plane and a bit short ranged by Japanese standards. I don't know as much about bombers/recon but what tradeoffs are you willing to make (other than having fewer specialised types in the interests of greater production)?

Armour/armament? Arguably a weak spot but with limited horsepower you face some tough choices. If you want to protect against .50 cal the armour and particularly the self-sealing tanks have to be so heavy you are trashing the performance of early war 1000hp planes, as the Americans found. And if you give up range you give up a lot of the early war victories. Yes to 20mm cannon or HMG a bit earlier on the Oscar.

Both their air forces did about as well as you could ask for at the start of the war. How much could they have improved in the next couple of years before they got completely swamped? I'm really not seeing a lot of plausible opportunity for qualitative improvement except maybe getting a Ki-100 (or less specialised J2M? Shiden or Hayate with Kasei instead of Homare?) type plane with carrier capability a couple years earlier. Not much in the big picture, which is a country punching hopelessly above its weight. As I think I wrote on the German thread...

 

[tomo pauk]

Rationalising production (fewer types) and training (a greater number of less elite pilots) seems obvious if not much fun.

Can you improve the engines? 18-cylinder radials are hard. Everyone was trying but only the Americans really got a lot of use out of them during WW2. If you're stuck with 14-cylinder the Kasei is pretty good. The Kinsei and Ha109 are not bad but a little small. Possibly some rationalisation here also - too many small engines which sucked up resources but were just not powerful enough by mid war. (Like Bristol - just focus on the damn Hercules and Centaurus!) The Mamoru might have been good if they could make it reliable.

Japanese have had a decent production of 18 cyl radials. Homare was a victim of ever-lower production and maintenance standards as the war was closing to the end, as well as fuel octane number not guaranteed to be 91/92 oct (me, I'd go with compression ratio of 6.5:1, if not of 6:1 instead of historical 7:1, in order to be still useful on lower-octane fuel). The Ha-104 was not used on fighters, so there is a missed opportunity. Both of the engines were made in few thousands - not that great when compared with 'Western' production numbers of ~2000 HP engines, but still an useful number.
Ha 109 was excellent, (un)fortunately Japanese failed to take advantage of the design and upgrade it, even if it is just addition of water/alcohol injection. Kasei was also very good, Japanese managed not to make an useful fighter around it ( Raiden was too late and too few to matter)
Yes, the small engines, like Zuisei and Sakae were over-produced.
The DB 601 licence production in two factories was the money not wisely spent, either.

2-stage superchargers? If you want to intercept B-29s you need altitude performance and they were trying but not very successfully (like the Germans). Again, this is hard. Were they missing anything obvious?

2-stage superchargers were known to work well at high altitudes already by mid-1930s, so yes, they missed the obvious.

Airframes? I don't think they did badly given the engines they were using. The A6M2 in particular is incredible for only 950hp. Could use a bit of tweaking in favour of high over slow speed manoeuvrability, but they were onto that pretty quickly. Probably the A7M was too ambitious a successor, they needed an intermediate with a 1500+hp 14-cyl rather than a 2000+hp 18-cyl (I don't know if the A6M8 would have worked out). The Ki-44 is also good but not a carrier plane and a bit short ranged by Japanese standards. I don't know as much about bombers/recon but what tradeoffs are you willing to make (other than having fewer specialised types in the interests of greater production)?

Excellent call on not making the number of specialized types.
Zero needed major engine upgrade at least by mid-1943, so it can sport all the requirements of the modern ww2 fighters: protection, performance and firepower. Kinsei or Ha-41/-109 would've looked just fine on the Zero, so don't wait until 1945 for the nose surgery. In the meantime, have Mitsubishi, Kawanishi and Nakajima work on the next-gen carrier-borne fighter, instead of Raiden, Kyofu and Gekko, respectively; no Saiun, install the cameras on other fast naval A/C.
Ki 43 needs to be replaced in production by mid-war; even a Sakae-powered Ki-44 is an improvement.
Kawasaki fighters' types - Ki-45 used twice the material resources and fuel when compared to Zero for no gain; Ki-60 and/or-61 with Japanese radials already in 1942 would've been just fine.

Armour/armament? Arguably a weak spot but with limited horsepower you face some tough choices. If you want to protect against .50 cal the armour and particularly the self-sealing tanks have to be so heavy you are trashing the performance of early war 1000hp planes, as the Americans found. And if you give up range you give up a lot of the early war victories. Yes to 20mm cannon or HMG a bit earlier on the Oscar.

Greater emphasis fighters with on better engines early on - Kinsei, Kasei, Ha-41 - would've enabled the Japanese to have their cake and eat it, too.
A belt-fed Type 99 by 1941 (or at least the 100 dr box for it) would've been a boon for the Japanese.

Both their air forces did about as well as you could ask for at the start of the war. How much could they have improved in the next couple of years before they got completely swamped? I'm really not seeing a lot of plausible opportunity for qualitative improvement except maybe getting a Ki-100 (or less specialised J2M? Shiden or Hayate with Kasei instead of Homare?) type plane with carrier capability a couple years earlier. Not much in the big picture, which is a country punching hopelessly above its weight. As I think I wrote on the German thread...

Focus on bigger radials ASAP, so the small radials by Nakajima and Mitsubish are not much less needed. Have Kawasaki and Aichi continue to make radials in ever greater quantities instead of DB 601s. Both air services would've been fielding the 370 mph fighters by 1942, with protection and good firepower. Don't waste time and resources on floatlplane-this and -that (makes Kawanishi delivering useful aircraft by 1941).
Licence-produced Fw 190 (with Japanese engines, guns etc) would've been a boon.

All of that needs to be backed-up by wide introduction of radars and greater emphasis on greater number of new pilots.

 

[hobbes154]

Japanese have had a decent production of 18 cyl radials. Homare was a victim of ever-lower production and maintenance standards as the war was closing to the end, as well as fuel octane number not guaranteed to be 91/92 oct (me, I'd go with compression ratio of 6.5:1, if not of 6:1 instead of historical 7:1, in order to be still useful on lower-octane fuel). The Ha-104 was not used on fighters, so there is a missed opportunity. Both of the engines were made in few thousands - not that great when compared with 'Western' production numbers of ~2000 HP engines, but still an useful number.

Well it would have been a useful number if they'd worked reliably, which they didn't, and if your 14-cyl are still working reliably under the same conditions that does indicate a specific problem with the 18-cyl (and if you're going 18-cyl, why as small as the Homare anyway?).

2-stage superchargers were known to work well at high altitudes already by mid-1930s, so yes, they missed the obvious.

I don't mean the obvious as in 2-stage superchargers are useful. I meant as in actually getting them to work in mass production versions in time to make a difference in the war, which only the US and UK achieved. Maybe they should have focused more on a mechanically driven 2nd stage and less on turbos which required metals (nickel?) they may not have had?

Excellent call on not making the number of specialized types.
Zero needed major engine upgrade at least by mid-1943, so it can sport all the requirements of the modern ww2 fighters: protection, performance and firepower. Kinsei or Ha-41/-109 would've looked just fine on the Zero, so don't wait until 1945 for the nose surgery. In the meantime, have Mitsubishi, Kawanishi and Nakajima work on the next-gen carrier-borne fighter, instead of Raiden, Kyofu and Gekko, respectively; no Saiun, install the cameras on other fast naval A/C.

Well I nicked that off previous posters.
By the time you give the Zero a major engine upgrade, protection, more/bigger guns, more fuel (in self sealing tanks!) to stop it losing too much range, strengthen the airframe to handle carrier landings with all of the above, and the wings to improve dive speed, how much of the Zero is left? Admittedly the outside is well streamlined so may still be worth keeping even if the innards are unrecognisable.

Licence-produced Fw 190 (with Japanese engines, guns etc) would've been a boon.

Why? It's short ranged, not particularly carrier suitable, relatively heavy and would have been late to the party especially once all the cooling issues were sorted. If you ditch the cooling fan what does it offer that's special? Nothing wrong with the Ki-44,-84,-100 airframes and why couldn't the latter two have been made into carrier a/c?

 

[hobbes154]

This thread might be useful background Japanese engine sizes

 

[tomo pauk]

Why? It's [Fw 190] short ranged, not particularly carrier suitable, relatively heavy and would have been late to the party especially once all the cooling issues were sorted. If you ditch the cooling fan what does it offer that's special?

Cooling issues and cooling fan remain in Europe, since I've specified that Japanese engines are used. Japanese engines are much lighter, so the Japanese-made Fw 190 will be lighter than the ones Made in Germany. Japanese engines were also getting better mileage than the BMW 801.
Fw 190's good points were it's rate of roll, low drag (probably lower than Ki-84 or Ki-100, since the 190 used maller and thinner wing), excellent in dive, high capacity for payload - both internal and external, both for fuel and weapons. It's airframe is/was regarded as very strong.

Nothing wrong with the Ki-44,-84,-100 airframes and why couldn't the latter two have been made into carrier a/c?

Japanese Army had no requirements for their aircraft to be carrier capable.

By the time you give the Zero a major engine upgrade, protection, more/bigger guns, more fuel (in self sealing tanks!) to stop it losing too much range, strengthen the airframe to handle carrier landings with all of the above, and the wings to improve dive speed, how much of the Zero is left? Admittedly the outside is well streamlined so may still be worth keeping even if the innards are unrecognisable.

Take a look into the Bf 109D being turned into Bf 109E, and then into the 109F, G and K. Or Spitfire, from I and II into V and later into IX; or the Spitfire XIV that tracked it's lineage from the Mk VIII, that in return probably took a few tricks from the Mk.III.
tl;dr: 'West' did it with their 'basic' fighters, Japanese/Mitsubishi also needs to do it.

I don't mean the obvious as in 2-stage superchargers are useful. I meant as in actually getting them to work in mass production versions in time to make a difference in the war, which only the US and UK achieved. Maybe they should have focused more on a mechanically driven 2nd stage and less on turbos which required metals (nickel?) they may not have had?

I agree with the suggestion.

Well it would have been a useful number if they'd worked reliably, which they didn't, and if your 14-cyl are still working reliably under the same conditions that does indicate a specific problem with the 18-cyl (and if you're going 18-cyl, why as small as the Homare anyway?).

There is no just one 18 cyl engine in Japanese ervice in 1944-45.
Discussion about the Homare: link

 

[Shortround6]

The turbos offer the "free" power of the exhaust to power the 2nd stage. We argue about the "free" part but compared to a mechanical supercharger there are a number of benefits.

This may allow for more power to had from poor fuel.

It may take several hundred hp to drive the 2nd stage, a lot depends on the amount of power you are looking for and where (altitude).
Anybody who has "Vee's for Victory" can look at pages 344-347 to get some charts and explanations.
The 2nd stage on the Allison could require anywhere from 200 to 300 hp depending on air flow. So if you are looking for (P-63) 1150hp at 25,000ft you need to be making over 300hp more in the cylinders than the engines in a P-38E with turbos. Which means you need better engine parts, you need a bigger cooling system or a lot more fins on the engine.

At 25,000ft you need to compress the air 2.7 times to get sea level air pressure which is why you need intercoolers.
100/130 fuel doesn't have more power than 92 octane fuel. It allows you to compress the mixture and heat it up more than lower octane fuel.
Now if you need to make 300-400hp (large radial) more power in the cylinders to drive the mechanical supercharger using low octane fuel you are in a world of hurt.
You can do it but you need good cooling of the mixture, good cooling of the engine. Water injection is going to be a necessity and it still isn't going to equal a turbo.

You can approach the turbo or at least do better than single stage engine but with low octane fuel you are really fighting a loosing battle.

 

[Shortround6]

By the time you give the Zero a major engine upgrade, protection, more/bigger guns, more fuel (in self sealing tanks!) to stop it losing too much range, strengthen the airframe to handle carrier landings with all of the above, and the wings to improve dive speed, how much of the Zero is left?

Nothing wrong with the Ki-44,-84,-100 airframes and why couldn't the latter two have been made into carrier a/c?

They would have needed strengthening and were too heavy (high wing loading).

The Japanese cannot match the American planes. They have to give up something or more than one thing. They could do better than they did and come closer.

They did not have the engineering staff. Nobody could match the Americans.
It isn't a matter of talented designers or Americans being smarter. The Americans simply had more engineers/draftsmen to begin with and could handle more projects despite wasting time on such things as the XP-54, XP-55, XP-56 and others (and the a number of engine projects that went nowhere).
It's the law of averages. The Americans had the luxury of designing 10 different aircraft and build the 5 good ones and junking the others. Most of the other countries were lucky to be able to design eight or some times only six (?).
The Americans could explore things that other countries could not. Simply do to size and resources.

 

[hobbes154]

Fw 190's good points were it's rate of roll, low drag (probably lower than Ki-84 or Ki-100, since the 190 used maller and thinner wing), excellent in dive, high capacity for payload - both internal and external, both for fuel and weapons. It's airframe is/was regarded as very strong.

Fw190 was a good airplane no doubt, but good enough to go through all the delay of getting the plans out by sub and then producing a foreign design with only blueprints (which went so badly for DB601 engine)? And how much of the low drag is due to the tight cowling/fan combo which you are ditching? Also crazy high wing loading by Japanese standards even compared to Ki-44 (and that will only get worse if you put more fuel in the wings, which will also hurt the roll rate).

Japanese Army had no requirements for their aircraft to be carrier capable.

Yeah I'm just playing with the whole inter service cooperation/standardisation fantasy.

Take a look into the Bf 109D being turned into Bf 109E, and then into the 109F, G and K. Or Spitfire, from I and II into V and later into IX; or the Spitfire XIV that tracked it's lineage from the Mk VIII, that in return probably took a few tricks from the Mk.III.

True but they were stronger airframes to start with, accepted shorter range as a tradeoff, and mostly didn't have to land on carriers (Seafire and 109T excepted). Might still be worthwhile but is it better than a navalised Ki-84 or -100?

There is no just one 18 cyl engine in Japanese ervice in 1944-45.

If the Ha-104 is so obscure it doesn't even rate an entry in Wikipedia or the list linked above that says something in itself. And 1944-5 really seems a bit late.

 

[hobbes154]

They would have needed strengthening and were too heavy (high wing loading).

Strengthening doesn't seem impossible (possibly less work than would be needed for an upengined Zero and certainly less than a whole new plane). 35 lb/sq ft also does not seem unmanageable for carrier landings even if a bit more than the Japanese were used to. They look to have reasonable if not stellar visibility forward and good wide landing gear.

The Japanese cannot match the American planes. They have to give up something or more than one thing. They could do better than they did and come closer.

I think we are all in furious agreement on that. Personally I would hazard that as they move to the defensive they could give up some range, but they still need to be lighter than the Americans especially if they don't have 2-stage supercharging, so that means less protection and dive speed. (I'm wondering if the weight penalty of protection against .50 cal is too much even with 1500+hp, at least for the fuel tanks.) So maybe Tomo's push for the A6M8 makes sense after all.

 

[tomo pauk]

Fw190 was a good airplane no doubt, but good enough to go through all the delay of getting the plans out by sub and then producing a foreign design with only blueprints (which went so badly for DB601 engine)? And how much of the low drag is due to the tight cowling/fan combo which you are ditching? Also crazy high wing loading by Japanese standards even compared to Ki-44 (and that will only get worse if you put more fuel in the wings, which will also hurt the roll rate).

Installing a smaller engine - Ha 109, Kinsei 60 series with water/alcohol injection, Homare - would've catered as lot for the loss of BMW 801's installation finesse.
Having the Ha 109 in the nose, for example, shaves 300 kg just on account of dry weight; lighter oil system, lighter prop and lighter engine bearers another 100? 400 kg less - circa 880 lbs for our imperial friends - is a lot for a small ww2 fighter. It was also 30mm smaller in diameter than the 801. The Ha 109 was a bit better on high altitudes than the 801C, and a bit less powerful on lower altitudes.
Wing loading has just gotten lower; make sure that better/more experienced pilots get the Ki 190 and you're golden.

Yeah I'm just playing with the whole inter service cooperation/standardisation fantasy.

Okay, roger that.

True but they were stronger airframes to start with, accepted shorter range as a tradeoff, and mostly didn't have to land on carriers (Seafire and 109T excepted). Might still be worthwhile but is it better than a navalised Ki-84 or -100?

I'm trying to do what Japanese were already doing from 1942 to 1945 on (ever-better firepower, introduction of s-s tanks and pilot's protection, and finally trying to install the Kinsei), but emphasis is for them to do the whole thing by early 1943 at latest. Zero is already navalized and with long range.
Advantage over the navalized Ki-84 and -100 is timing. Better timing is of essence.

If the Ha-104 is so obscure it doesn't even rate an entry in Wikipedia or the list linked above that says something in itself. And 1944-5 really seems a bit late.

Wikipedia entry for the Ha-104: link
That Ha-104 has no Wikipedia entry in Engilsh language is on the article writers, not on Ha-104. This site has materials on Japanese engines, including the Ha-104.
Japanese need to start doing things differently alredy from 1941, in order that hardware from 1944 makes sense.