# Jack vs. Tojo - Which was better? Why? (1 Viewer)



## Conslaw (Nov 24, 2017)

The Japanese Navy's J2M "Jack" fighter and the Japanese Army's Ki-44 "Tojo" fighter were similar in concept and similar in overall performance. Was one better than the other? Why?​

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## Greg Boeser (Nov 25, 2017)

I'm going with the Jack.
Better armed, better climb, better top speed, better ceiling. Just better. And it was a newer design. Ki-44s were being replaced by Ki-84s about the same time the Jack was coming online.


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## Conslaw (Nov 25, 2017)

I'm going with the Tojo. It was ready for service a year earlier. They made twice as many of them. The top speeds were similar. They both had a good climb rate, though Jack was better. The Tojo was starting to be phased out in latter 1944 because the Ki-84 Frank was a supurb aircraft that was producable and could perform multipl roles. The navy's (post-zero) general purpose fighters, the A7M and the N1K1, were either not ready for production at all (A7M) or defied mass production (N1K - peak production 106 units/month in Sept. 1944). (Ok, in part I picked the Tojo just to be contrary. I admit it.)

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## tomo pauk (Nov 25, 2017)

Early Tojo, powered by Ha-41, was not as fast as the later Tojos powered by Ha-109 engines. Once Jack arrived, it looked as a better fighter to me. BTW - Tojo was produced in small monthly quantities, monthly average being less than 50 examples.

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## Shortround6 (Nov 26, 2017)

Hmmmm , 2 years newer, engine over 20% more powerful, Looks like the Jack has some definite advantages.

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## GregP (Nov 26, 2017)

I think the J2M was the only IJN fighter capable of reliably intercepting the B-29. But they didn't make many, around 670 or so. Also, the quality declined as raw materials became scarce. In good trim, the J2M was formidable.


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## alejandro_ (Nov 27, 2017)

On paper the Jack was superior, but Tojo was far more reliable. 302 Kokutai reported that no more than 30% of Jacks were usually available. Jack had very serious production issues.

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## GregP (Nov 27, 2017)

Mostly engine and landing gear issues, more engine than LG. Haven't heard of any propeller issues.


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## Conslaw (Nov 27, 2017)

Both the Jack and the Tojo were interceptors. Having a good radio is important to an interceptor. Of course, the Zero is known for having a nearly useless voice radio. Were the radios in the Jack and the Tojo better?


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## Ivan1GFP (Nov 30, 2017)

By most book listings, the Ki 44 and J2M were pretty comparable in speed, but the TAIC tested a J2M2 Jack 11 at 407 MPH maximum speed and a J2M3 Jack 21 at 417 MPH which makes the J2M a much faster aeroplane. My understanding is that the typical 370 MPH maximum speed for J2M is for "Overload Fighter" which meant it was carrying a drop tank. The pilot reports also gave the J2M pretty high marks for maneuverability and general handling. I don't have corresponding information on Ki 44 but don't think it was as good.

My vote is for Raiden.

- Ivan.

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## XBe02Drvr (Dec 1, 2017)

Unfair comparison! Like comparing an Emil to a Spit 14. Half a generation apart. How about a KI84?
Cheers,
Wes

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## Zipper730 (May 20, 2019)

I would say that the J2M is the better choice as, from what I've found on WW2 Aircraft Performance it has the P-51 beat in climb all the way up to 25000 feet (escort configuration, pylons on wings, tanks punched off), and could get up to around 407-408 mph, with other sources listing around 417 (that said, the P-51B using 75" of MAP to 17900', followed by switching to 67" above that point would keep the P-51 on top from sea level to around 3000-4400; then somewhere between 15000-20000' and up)

They planned to put a turbocharger in the J2M4 from what I read, and if so, it would have been a royal bastard to face off against.

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## Ivan1GFP (May 21, 2019)

Hello Zipper730,
The fuel issue with J2M was the same one that affected other high performance Japanese engines.
Their best fuel standard that was commonly available was either 91 octane for the Army or 92 octane for the Navy.
To compensate for this, most of the late war Japanese fighters carried a LOT of Water-Methanol as an anti-detonant and would use it at settings barely above cruise.
The J2M3 as an example which could carry around 570 liters of internal fuel would also be carrying 120 liters of Water-Methanol.

This was when things were working as intended. As the war progressed and their shipments of oil were interrupted, the fuel quality got worse.

Some of the older engines such as on Ki 43-II and most A6M didn't need ADI to make their maximum power but they also were using lower manifold pressures.

- Ivan.

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## Zipper730 (May 21, 2019)

Ivan1GFP said:


> most of the late war Japanese fighters carried a LOT of Water-Methanol as an anti-detonant and would use it at settings barely above cruise.
> The J2M3 as an example which could carry around 570 liters of internal fuel would also be carrying 120 liters of Water-Methanol.


31.5 gallons of water methanol. How much did we carry in the US?


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## Ivan1GFP (May 21, 2019)

Zipper730 said:


> 31.5 gallons of water methanol. How much did we carry in the US?



Hello Zipper730,
The P-47D-3 through P-47D-25 carried 15 Gallons
After the P-47D-25, this was increased to 30 Gallons.

For internal fuel, before the D-25, total was 305 Gallons.
D-25 and later had 370 Gallons.

- Ivan.


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## Shortround6 (May 21, 2019)

The F4U and F6F carried closer to 10 gals.


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## CORSNING (May 22, 2019)

XBe02Drvr said:


> Unfair comparison!
> *I am agreeing with Wes on this one. The Demon Vanquisher (Ki.44-II) was
> first delivered to the JAAF in Nov./Dec. 1942. The god of thunder/lightning
> (J2M2) was not delivered to the JNAF until Dec. 1943. During wartime, that
> ...


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## Ivan1GFP (May 22, 2019)

Hello Corsning,
While it is true that the Ki 44 Shoki came out earlier, it and J2M Raiden were both were designed for the same role (Interceptor) and both were in service for their respective air services at the same time.
While the Ki 84 was a more contemporary design to J2M, it was more of a general purpose fighter than an interceptor.
The naval equivalent would have been the N1K2-J Shiden-KAI.

As GregP pointed out, there were some problems with the engine installation in the J2M, but perhaps they were not what one might expect.
The engine was the Mitsubishi Kasei. It was a "Bomber Engine".
It was not the more troublesome Nakajima Homare.
The Mitsubishi Kasei was a pretty well proven and reliable engine design unlike the Homare.
The Homare was a small diameter engine (nearly the same as Nakajima Sakae) but with about twice the power if it worked right.
The Kasei was a very large diameter engine with a bit less power and typical installations were on bigger aircraft such as the Kawanishi H8K Emily where the streamlining wasn't so important. Power output and RPM were also much lower.

The big issue was that in order to get a nice pointy nose on the J2M, the Kasei needed an extension shaft and a cooling fan and that setup resulted in a few problems initially. There were other changes with fuel injection and such to raise the output of the engine but I am not sure if those resulted in any significant problems.

In general, allied reports praised the flying qualities and construction quality of the J2M. I don't have equivalent information on Ki 44.

- Ivan.

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## Zipper730 (May 22, 2019)

Who are we pitting against these aircraft?


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## CORSNING (May 22, 2019)

*Hi Ivan, good to hear from you sir.*



Zipper730 said:


> Who are we pitting against these aircraft?


*Pick your poison Zipper and I will see what information I have. *

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## CORSNING (May 22, 2019)

alejandro_ said:


> On paper the Jack was superior, but Tojo was far more reliable. 302 Kokutai reported that no more than 30% of Jacks were usually available. Jack had very serious production issues.


*An extremely good point Alejandro. This point added to the slightly better turn of the Ki 100
is exactly why the Japanese pilots preferred it over the Ki 84....IMHO.*


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## Zipper730 (May 22, 2019)

I've done some thinking and based on posts further down, I've revised the following

1. Ki-44 against

P-38F: It was the early P-38 variants and was available in 1942
P-40D/E: They were available early on in the war
F4U-1: Early variants were available as of the last few days of December 1942
F6F-3: Available in 1943

2. J2M against

Tempest II: There were plans to use these for the Tiger-Force as escorts
Spitfire IX/XVI: Not sure how many of those served in the Pacific, but they were great fighter planes
P-63 Kingcobra
P-47N Thunderbolt

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## Shortround6 (May 22, 2019)

One might also try the the Ki-44 vs the P-40K, pr P-39K.
The Ki-44 with the Ha-109 engine began production in the fall of 1942.


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## Greg Boeser (May 22, 2019)

AVG Tomahawks and RAF Buffalos were facing Ki-44s in December '41 and January '42.
14th AF P-40Es and Ks were dealing with Ki-44s in spring and summer of '43.
After smacking Ki-27s and Ki-43s around, the Shoki came as a big surprise.
The 23rd FG even felt that P-51As were no match for the Ki-44.
When did the Jack have it's combat debut?


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## Shortround6 (May 23, 2019)

Greg Boeser said:


> When did the Jack have it's combat debut?


I don't know but the first service unit to get the JM2 didn't get them until Dec of 1943 and it was a home defence unit.


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## CORSNING (May 24, 2019)

Ki-44s first combat was 15 January 1942 over Singapore with the Independent 47th Air Squadron.
The Raiden interred combat first over the Marianas in June 1944.

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## CORSNING (May 24, 2019)

Greg Boeser said:


> The 23rd FG even felt that P-51As were no match for the Ki-44.



What I was able to find from the 76th FS:
"Upon his return to Kweilin, veteran ace "Tex" Hill expressed doubt
about the P-51(A)s ability to fight the 'Tojo', stating, 'I don't think
we can beat these new Japs in the air'. Chennault was unfazed, however,
replying, 'Don't worry about it. Just hit them on the ground'."

On 1 December 1943 Tex Hill was flying with five other P-51A pilots. They
were escorting B-24s and were bounced by Ki 44s. Two of the P-51As
were shot down without loss to the Shokis. This was just an isolated
incident. But, the Ki 44-II could out climb, out roll, out accelerate and
possibly outturn the P-51A. The Mustang was faster and could out
dive the Ki-44, but the Ki-44 did dive very well also.

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## Greg Boeser (May 24, 2019)

Yeah, I've read Molesworth's _Sharks Over China._


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## Glider (May 24, 2019)

Few would deny that the Ki44 is one of those often overlooked aircraft of WW2. Had the Japanese switched Ki44 production for Ki43 life wold have been far more difficult for the Allies.

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## CORSNING (May 25, 2019)

Greg Boeser said:


> Yeah, I've read Molesworth's _Sharks Over China._



Hi Greg,
My information, in part, comes from "Ki-44 'Tojo' Aces of World War 2". Osprey Aircaft
of the Aces 100. Some information comes from Air Enthusiast July 1972 Vol.3 No.1. And
some came from www.yarchive.net.


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## CORSNING (May 25, 2019)

Glider said:


> Few would deny that the Ki44 is one of those often overlooked aircraft of WW2. Had the Japanese switched Ki44 production for Ki43 life wold have been far more difficult for the Allies.



From http://www.yarchive.net/mil/ki-43.html

"Not to be overlooked is the Ki-44, the performance of which was more or less comparable
to the Fw 190A series. but with a faster rate of climb." "The P-40 was simply outclassed by
it, and had the Japanese Army pushed Ki-44 units into New Guinea in 1942, it would definity
been bad..."


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## taly01 (May 25, 2019)

There is no comparative fly offs of Allied vs Ki-44 and J2M like they did for Zero. I think the J2M is a much more advanced and superior performer, and has 2-4x20mm as standard, where the Ki-44 had 4x12.7mm as standard.

The little I've found from the Japanese side is that they didn't consider the J2M able to defend itself in a dogfight (one reason the N1K-J was given production preference over the J2M). Also the Ki-44 was not considered a good plane by most Japanese as it turned poorly compared to Ki-43 and Ki-61, and it was a handful to land for new pilots.

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## CORSNING (May 25, 2019)

T.A.I.C. Tojo 2 report 155A dated March 1945. Revised from the December 1944
report.
( T.A.I.C. Jack 11 report 105A dated December 1944 )

Altitude / Speed / Climb / Time to height
Meters / MPH / FPM / Minutes to altitude
S.L.........335/4140/----..(350/4670/----
-1,000..347/4200/--.7..(364/4670/--.6
-2,000..361/3950/-1.7..(379/4300/-1.3
-3,000..361/3500/-2.7..(379/3950/-2.3
-4,000..368/3490/-3.65(388/4060/-3.0
-5,000..380/3300/-4.7..(403/3750/-4.2
-6,000..380/2765/-5.8..(402/3280/-5.2
-7,000..373/2240/-7.3..(397/2750/-6.8
-8,000..360/1715/-8.9..(388/2170/-8.2
-9,000..345/1190/11.5..(377/1700/-9.6
10,000..322/-665/N.G...(363/1050/11.8-12.0
11,000..260/-140/N.G...(340/-680/N.G.

Engines: Nakajima type 2 1,570 hp./5,000 ft. (Mitsubishi Kasei 23 1,940 hp./4,400 ft.)

Combat Weights: 6,100 lb. (7,080 lb.)

Service Ceilings: 36,350 ft. (39.600 ft.)

Wing Loading: 37.78 (32.805) lb./sq. ft.

Power Loading: 3.885 (3.649) lb./hp.

Armament: 2 x 7.7 mm/500 rpg. or 2 x 12.7 mm/250 rpg. + 2 x 12.7 mm/ 250 rpg.
( 2 x 7.7 mm/550 rpg. or 2 x 20 mm/100 rpg. + 2 x 20 mm/100rpg.)


I have a work up on all the other aircraft mentioned previously, F4U-1, Buffalo, P-51D &
the rest, but that is not what the title of this thread is calling for.

Jeff


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## CORSNING (May 25, 2019)

Note: The Ki 44-III prototype powered by a Nakajima Ha-145 was
completed in June 1943 with an increased wing area of 204.52 sq.
ft. and a larger tail. This version was designed to carry four 20 mm
cannon or 2 20 mm cannon and 2 37 mm cannon. The combat
weight of the prototype was 5,357 lb. and the increased wing
area would give it a wing loading of 26.19 lb./sq. ft. The power
loading of the 2,000 hp. Ha-145 would have placed it at 2.678 lb./ hp.
That is the best power to weight ratio of any WW2 fighter I have ever
read about. Superlative acceleration and climbing ability. Makes
one wonder why....?

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## XBe02Drvr (May 25, 2019)

CORSNING said:


> That is the best power to weight ratio of any WW2 fighter I have ever
> read about. Superlative acceleration and climbing ability. Makes one wonder why...?


Works great....when it works!

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## Conslaw (May 25, 2019)

I'm wondering if development of the Ki-44 was stunted because they IJA knew they wouldn't have a steady stream of high powered engines to put in them.


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## CORSNING (May 26, 2019)

J2M3 m21 vs. P-47N.
The following quote is from page 53 of Erik Pilawskii's 'Fighter Aircraft
Performance of WW2'.
" The J2M3 was remarkable for its tremendous flying horsepower, possessing
what was likely the most formidable power loading of any aircraft in the Pacific
war. Meanwhile, the P-47N model was a longer ranged development of the
P-47D, complete with larger wings and increased tankage. Against the 'Jack',
the Thunderbolt would have to rely on its *modest speed advantage**, being
inferior to the J2M in every other performance characteristic. With equal pilots
at the controls this would not have been enough, and it is hard to see past a
victory for the J2M3 under normal circumstances."

The normal power loading for the Model 21 was about 3.65 lb./hp. which was
very good compared to the '47N's 5.64 lb./hp.

P-47N (J2M3 with 92 octane and smooth running engine.)
432 (402) mph/6,000 m.
444 (397) mph/7,000 m.
456 (388) mph/8,000 m.
463 (377) mph/9,000 m.
467 (363) mph/10,000 m.

*Modest speed advantage?

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## BiffF15 (May 26, 2019)

CORSNING said:


> J2M3 m21 vs. P-47N.
> The following quote is from page 53 of Erik Pilawskii's 'Fighter Aircraft
> Performance of WW2'.
> " The J2M3 was remarkable for its tremendous flying horsepower, possessing
> ...



Concur on the modest part. Not taken into consideration is the pilot product on the stick and rudders and their training time / experience. It would be interesting to see a quarter by quarter break out by country for the war years, with pilot hours and type (fighter, trainer, bomber, transport). It would I think show tremendous declines on the Axis side, or a big fall from the beginning to end.

Cheers,
Biff


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## taly01 (May 27, 2019)

The super high performance quoted for late war US planes like P-47N and P-51H are using 80-90" of boost! I am not sure if 80-90" boost would be used by the fighter planes flying 850 mile over water from Iwo Jima to Japan. Using safer (rated) levels of boost the performance is still great, but is then almost the same as J2M using their own high boost over their own land.

FLIGHT TESTS OF THE P-47N AIRPLANE AAF NO. 44-88406 
Speed at Military Power (53inch boost) 
423mph at 38,000ft.
372mph at 15,000 ft.

P-47N sustained rate of climb is only around 1560-1740ft/min below 25,000ft at Military Power!

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## XBe02Drvr (May 27, 2019)

taly01 said:


> I am not sure if 80-90" boost would be used by the fighter planes flying 850 mile over water from Iwo Jima to Japan. Using safer (rated) levels of boost the performance is still great, but is then almost the same as J2M using their own high boost over their own land.


In air combat, you get no points for second place. I'm sure they babied their engines (if you can call "lugging"* the engine in super lean mixture and high cylinder head temps "babying") in the long cruises to and from the target area, but when the bad guys show up you do what you've got to do. The R2800 was a phenomenally tough engine, and if the choice is between over boosting your engine and getting the other guy before he gets you, versus babying your engine and becoming a guest of the Emperor (or worse), well that's a no-brainer in my book.
Cheers,
Wes
*For you folks unfamiliar with American slang, "lugging" is forcing an engine to run "oversquare" (high Manifold Pressure and BMEP and low RPM - Lindberg's max range technique), kind of like driving up a hill in forth gear at low speed with pedal to the floor and your engine shuddering, pinging, and protesting. This, combined with a super lean mixture leads to high cylinder head temps and stresses that can be damaging to engines less robust than an R2800.

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## michael rauls (May 27, 2019)

taly01 said:


> The super high performance quoted for late war US planes like P-47N and P-51H are using 80-90" of boost! I am not sure if 80-90" boost would be used by the fighter planes flying 850 mile over water from Iwo Jima to Japan. Using safer (rated) levels of boost the performance is still great, but is then almost the same as J2M using their own high boost over their own land.
> 
> FLIGHT TESTS OF THE P-47N AIRPLANE AAF NO. 44-88406
> Speed at Military Power (53inch boost)
> ...


Yes but the Thunderbolt can still pull the better numbers out of a hat when/ if it really needs them using the higher boost for a short period I would think.
Also an advantage the p47 has over most other planes including the Jack is it's superior high altitude performance which if utilized properly would translate into either they come up to where the p47 has the much superior performance or they stay in a position where the Thunderbolt has the altitude/ energy advantage on them.
Kind of a loose/ loose for the Jm2. Not saying it's a hands down, walk away one sided contest but that would seem to give the p47 a distinct hard to counter edge over the Jack( and most planes) that doesn't show up in raw performance stats.


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## taly01 (May 27, 2019)

> and if the choice is between over boosting your engine and getting the other guy before he gets you, versus babying your engine and becoming a guest of the Emperor (or worse)



The (or worse) could be ditching part way back to Iwo Jima and hoping you get found before sharks get to you!

P-47 Thunderbolt's best escape tactic is basically a power dive...... interestingly Akamatsu who is probably the most successful Raiden pilot also usually used an escape dive after a firing pass.

Also one translation of the Japanese name Raiden is Thunderbolt!

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## XBe02Drvr (May 27, 2019)

taly01 said:


> The (or worse) could be ditching part way back to Iwo Jima and hoping you get found before sharks get to you!


Most fighter pilots would accept that risk in preference to being shot down over the target area. I know I would. There's a reason for the slogan, "faith in God and Pratt and Whitney".
Cheers,
Wes

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## Shortround6 (May 27, 2019)

US had some subs and a number of PBYs assigned to pilot recovery. Certainly not a guarantee of safety but offered a chance.


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## michael rauls (May 27, 2019)

I wish I could be more specific but here goes, I read an article on the internet( so take with salt grain, maybe 2) a while back that they did a test in a p47 in early 44 to see how long the engine could be run at verry high boost( wish I could remember the exact numbers but just remember it was far in excess of normal), basically after an hour of this is was still running and undamaged much to everyones suprise.
I guess that Pratt and Whitney was one tough motor.


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## BiffF15 (May 27, 2019)

taly01 said:


> The (or worse) could be ditching part way back to Iwo Jima and hoping you get found before sharks get to you!



It’s the enemy you know (the guy in the other plane who is winning) versus the enemy you don’t know (engine longevity after pushing it). The former is a guaranteed to put you into a bad place while the latter is not.

Wes is correct 😎.

Cheers,
Biff

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## Greg Boeser (May 27, 2019)

James Muri reported running his R-2800-5s at 70" and 2650 rpm for over a half hour to clear the Kido Butai after attacking the _Akagi_ at Midway. And these were the early A- series engines.


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## alejandro_ (May 27, 2019)

> T.A.I.C. Tojo 2 report 155A dated March 1945. Revised from the December 1944
> report.
> ( T.A.I.C. Jack 11 report 105A dated December 1944 )



Thanks for that information Corsning. Do you have data for the Tojo 1 as well?


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## taly01 (May 28, 2019)

I'm not saying the Raiden will outperform the P-47N even if its only at 52", but data sheet racing isn't combat proof, and its interesting that the USAAF P-47N tests on www.wwiiaircraftperformance.org are only at a WEP of 53", and they added this.........



> FLIGHT TESTS OF THE P-47N AIRPLANE
> AAF NO. 44-88406 ............
> ...........At high power settings considerable maintenance was involved because of oil leaks, cracked vacuum pump housings, exhaust collector rings burning out and oil leaks. At war emergency power these malfunctions become excessive and operation was restricted at this power. In military power climbs high oil and cylinder head temperature above 30,000 ft. were experienced and made it necessary to reduce power after ten minutes of operation to cool the engine.



There is a already a thread about it on here Overboosting the P-47's engines: need some clarifications


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## CORSNING (May 28, 2019)

72"Hg was war emergency for these aircraft engines. 54.3"Hg was military.

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## CORSNING (May 28, 2019)

alejandro_ said:


> Thanks for that information Corsning. Do you have data for the Tojo 1 as well?


Sorry Sir, I do not have a TAIC report on the Ki-44-I.
Your thank you is appreciated. You are quite welcome sir.


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## Zipper730 (May 28, 2019)

CORSNING said:


> J2M3 m21 vs. P-47N.
> The following quote is from page 53 of Erik Pilawskii's 'Fighter Aircraft
> Performance of WW2'.
> " The J2M3 was remarkable for its tremendous flying horsepower, possessing
> ...


Looking at these figures, it seems as if the top speed was based around the 72" overboost?


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## PAT303 (May 28, 2019)

First ever post, I remember reading somewhere that if high boost and water injection is used the engines require a strip down?.


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## Shortround6 (May 28, 2019)

PAT303 said:


> First ever post, I remember reading somewhere that if high boost and water injection is used the engines require a strip down?.


that may have varied (considerably?) with time. By 1946/47 water injection was being used routinely for take-off on transport aircraft. 2400hp/ 2800rpm/56.0in(+13lbs) on the Commercial C series engines. 
In 1943 the engines may certainly have required much often spark plug changes and oil inspections than engines not using water injection and high boost. Actual strip downs/overhauls might have been deemed necessary depending on the hours already on the engine and any metal particles found in the oil?

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## taly01 (May 29, 2019)

The power vs height graph is great and it shows what they were mentioning in the other thread that 72"+ boost cannot be made > 20,000ft as the turbo/supercharger cannot generate that pressure at thin air altitudes.



> I remember reading somewhere that if high boost and water injection is used the engines require a strip down?.



On the P-40 at least to get WEP you had to push the throttle through a wired stop gate, and when you got back the mechanics would curse you behind your back for making them do an engine pull down! I guess the P-47N had some similar system so mechanics would know you went to War Emergency Power.


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## Shortround6 (May 29, 2019)

I don't believe that EVERY use of WEP required an "engine pull down". It might depend on what is meant by an "engine pull down". 

To get a WEP rating an American engine (other countries had different requirements) had to accumulate 7 1/2 hours running time on a test engine at that power rating without breaking anything (or only a few minor problems/accelerated wear). This could be done in 5 minute intervals with cooling off periods in between or all at once or some combination. 

It was up to the squadron engineering officer most of the time to both monitor the engines and implement suggested maintenance procedures. 
Some types of engines required more frequent spark plug changes (perhaps as often as 20 hours) if WEP settings were used. No mechanic is going to thank the pilot for for making him/them change 18-48 plugs (48 plugs on a P-38) but that is not quite an "engine pull down". 
Again, this could change with local conditions. If you were in some god forsaken airfield with poor supplies they may have already been reusing plugs (pulling them, cleaning and replacing) and the engineering officer may have decided that every use of WEP required pulling the plugs until they got new ones? 

Depending on _when_ water injection was used it might have contaminated the oil (or they were afraid it would) which might require draining what oil was left and replacing it. If water was used on take-off for a multi hour flight the water/alcohol would have evaporated out of the oil by the time the plane landed. 
Oil samples might be pulled for examination/analysis for metal particles (sign of bearing failure.)

If an engine was supposed to be good for 240 hours (number out of hat) before overhaul then every 5 minute use of WEP might shorten that time by one or more hours, depends on the engine in question and the experience of the engineering officers in that theater and the recommendations from the manufacturer. 

What procedures were on an Allison in the fall of 1942 and what the procedures were on an R-2800 in the spring of 1945 might be very different. 

I will note that Allison, P & W and RR Merlins all gained in overhaul life during the war while operating at increased powers. A discreet curtain will be drawn over the Wright R-3350 however

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## Capt. Vick (May 30, 2019)

Jack...based on looks alone

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## Ivan1GFP (May 31, 2019)

CORSNING said:


> J2M3 m21 vs. P-47N.
> The following quote is from page 53 of Erik Pilawskii's 'Fighter Aircraft
> Performance of WW2'.
> " The J2M3 was remarkable for its tremendous flying horsepower, possessing
> ...



Hello Corsning et al.
Part of the problem with this comparison of maximum level speeds is that it leaves out the detail about how long it takes for each aircraft to get up to speed.

The P-47M with the same engine as the N model was used in small quantities in Europe.
One of them, "Wonderful Winnie" was used by its pilot to race against unsuspecting Mustangs for money and won those races. The accounts of those races were that on the start of the race, the Mustangs would build up a pretty good lead because of the rather slow acceleration of the P-47M.
Eventually the Thunderbolt would overtake the Mustangs, but it took a while to even catch them.

Consider that the P-47N is heavier than the P-47M and also a couple MPH slower.
The speed advantage is also mostly at very high altitude where the J2M probably would not be.
The J2M as mentioned has a particularly high power to weight ratio and probably a very good acceleration as a result and that may lessen the apparent speed difference.

- Ivan.

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## Shortround6 (May 31, 2019)

Since the Jack was newer by several years (at least in combat form) and used an engine that was about 20% more powerful the Mitsubishi company would have had to really screw up not to build a better combat plane. 
However if you are trying to decide which was the better plane in late 1942, all of 1943 and most of 1944 then the Tojo wins

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## XBe02Drvr (May 31, 2019)

Shortround6 said:


> However if you are trying to decide which was the better plane in late 1942, all of 1943 and most of 1944 then the Tojo wins


You can't win the fight if you don't make it to the ring by show time!

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## alejandro_ (May 31, 2019)

Many years ago I made a comparison of Ki-44 with different fighter aircraft of 1942-43 and 44-45. Even late in the war the climb rate was competitive.

1942-43:












1944-45:










I am planning to update the article at some point. Perhaps someone has suggestions on other aircraft to which it could be compared, especially in 1942-43 (Buffalo, Hurricane...).

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## Kevin J (May 31, 2019)

A better comparison for the Raiden would be the Ki-61-II / Ki-100. They're deliverable in the same timescale.


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## CORSNING (May 31, 2019)

Ivan,

The speed advantage is also mostly at very high altitude where the J2M probably would not be.

*The P-47N escorted the B-29s. Original bombing of the B-29s over Japan was its 
cruising altitude of 30,000 ft. Later it was restricted to night missions at a lower
level. I am not a historian of bomber aircraft, so I do not know at what altitude
the night missions were flown at.*

The J2M as mentioned has a particularly high power to weight ratio and probably a very good acceleration as a result and that may lessen the apparent speed difference.
*Agreed sir. The Raiden was a more dynamic aircraft.*


*Jeff*


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## Greg Boeser (May 31, 2019)

Night bombing was conducted under 10,000'.

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## XBe02Drvr (May 31, 2019)

taly01 said:


> I'm not saying the Raiden will outperform the P-47N even if its only at 52", but data sheet racing isn't combat proof


So what does history have to say about combat proof? How often did they actually meet in combat? What were the outcomes? What did the pilots have to say?
The scenario depicted above by Mike Rauls makes a lot of sense. Given the P47's altitude performance and the B29s' daylight bombing altitudes (pre LeMay), they were likely flying top cover, if they were there at all, and thus likely to be bouncing Raidens from above. (Port Moresby redux, with the roles reversed.) I had always understood those long range B29 escort missions to be a Mustang show.
Cheers,
Wes


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## Zipper730 (May 31, 2019)

Greg Boeser said:


> Night bombing was conducted under 10,000'.


Just to be clear, did they climb to 14000-25000 feet then drop to below 10000 feet prior to bombing or just cruise in and out at below 10000 feet above MSL.


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## Shortround6 (May 31, 2019)

It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.


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## Zipper730 (May 31, 2019)

Shortround6 said:


> It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.


From what I remembered...

Cruising high allows more speed for the same engine power
Climbing to higher altitude expends more energy than climbing to a more moderate altitude (big problem if climb-rate is far too slow)
I would have thought that climbing to 10000' would reduce energy to climb, but would have required more energy to carry it along, I figured 15-25k would be high enough to reduce drag and increase speed, yet not too much to undermine fuel consumption.


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## Ivan1GFP (Jun 1, 2019)

CORSNING said:


> Ivan,
> 
> The speed advantage is also mostly at very high altitude where the J2M probably would not be.
> 
> ...



Hello Corsning,
Years ago, I asked a related question to a fairly knowledgeable fellow about why the B-29s didn't continue to bomb from around 30,000 feet where they were pretty much immune to interceptions.
His explanation was that although the B-29 could easily sustain those altitudes, bombing accuracy was pretty lousy because of the wind conditions (Jetstream) at that altitude. It made more sense to bring the bombers down lower so they could actually hit something. By that stage of the war, interceptions by fighters were not considered to be as risky to the point that most of the bombers were not carrying all their defensive armament anymore anyway, though tail guns were usually retained.

Another interesting tidbit to consider is that the J2M3 as tested by TAIC was actually a bit faster than your chart shows. It should be 417 MPH. 407 MPH is the speed attributed to the J2M2 that was tested.
The J2M3 sometimes had broad blade propellers installed, but the one that was tested did not have those.
They can be recognized by corners at the root of each propeller blade. I don't know if that difference would have improved speed, but I would expect that a bigger propeller would not have been installed if it didn't help anything.

- Ivan.

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## XBe02Drvr (Jun 1, 2019)

Shortround6 said:


> It might depend on the mission, but climbing to 25,000 on the way in could burn hundreds (many hundreds) of gallons of fuel. By not climbing to 25,000ft they could carry more bombs further.





Zipper730 said:


> I would have thought that climbing to 10000' would reduce energy to climb, but would have required more energy to carry it along.


Turbocharged recips don't suffer the huge low altitude fuel penalties that gas turbine aircraft do. A jet or turboprop B29 would have needed to climb to FL300 or higher for the long haul, even if attack altitude was 10K or less. Flying all the way at attack altitude would burn less fuel overall and keep them under the radar horizon much closer in to the target. That last 10K of climb in the thin air above 20K would be a long, slow, thirsty slog for heavily laden B29s.
On my way back from Aircraft Escape and Rescue Training at NAS Cecil, I hitched a jump seat ride in an Eastern DC9-10 from JAX to MIA with a couple of Navy trained Eastern pilots, both still active in the reserves, and both former "mustangs". Our flight profile (not the standard filed flight plan) was a max rate climb to FL260, 50 miles NE of Orlando, then a flight idle descent into MIA. It was late at night, we were high on the approach profile, traffic was dead, and the crew talked the controller (another ex-squid) into letting us do a high altitude military style teardrop penetration approach (not a peep from the cabin, just snores). The power levers stayed at idle until it was time to dirty up for landing. Fuel burn beat the programmed number for the standard FL180 flight plan by 15%, and we beat the scheduled flight time by 7 minutes. That's how dramatic the altitude difference is with turbines.
One of my buddies from the flying club taxied up to the gate as we were deplaning about 0100 (on to the tarmac; jetways all occupied by morning departures), and got me back to NQX in time to catch a few winks before morning muster.
Biff, Flieger, and any other active airline pilots out there, that was nearly fifty years ago, and rules were a tad different then. I even got my Commercial and CFI without an Instrument Rating at first. Had to upgrade in 1975.
Cheers,
Wes

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## taly01 (Jun 1, 2019)

> However if you are trying to decide which was the better plane in late 1942, all of 1943 and most of 1944 then the Tojo wins


More widespead use of the Ki-44 in 1943 is one of the great "what-ifs" for Japanese aircraft. It never happened for several reasons 
1) Range for Ki-44 was much less than Ki-43/61, and in the South Pacific range is king, 
2) Handling of Ki-44 was much more difficult than Ki-43/61 both in flight and especially landing for new pilots.
3) Ki-61 was the standard new fighter for 1943 that met all requirements. (unfortunately was unreliable maintenance nightmare).

They did send extra Ki-44 to Burma in mid'44 to counter the newly arrived Spitfire VIII. From memory they didn't perform much better than the Ki-43 already there.


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## CORSNING (Jun 1, 2019)

Ivan1GFP said:


> Hello Corsning,
> Years ago, I asked a related question to a fairly knowledgeable fellow about why the B-29s didn't continue to bomb from around 30,000 feet where they were pretty much immune to interceptions.
> His explanation was that although the B-29 could easily sustain those altitudes, bombing accuracy was pretty lousy because of the wind conditions (Jetstream) at that altitude. It made more sense to bring the bombers down lower so they could actually hit something. By that stage of the war, interceptions by fighters were not considered to be as risky to the point that most of the bombers were not carrying all their defensive armament anymore anyway, though tail guns were usually retained.
> 
> ...


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## BiffF15 (Jun 1, 2019)

XBe02Drvr said:


> Turbocharged recips don't suffer the huge low altitude fuel penalties that gas turbine aircraft do. A jet or turboprop B29 would have needed to climb to FL300 or higher for the long haul, even if attack altitude was 10K or less. Flying all the way at attack altitude would burn less fuel overall and keep them under the radar horizon much closer in to the target. That last 10K of climb in the thin air above 20K would be a long, slow, thirsty slog for heavily laden B29s.
> On my way back from Aircraft Escape and Rescue Training at NAS Cecil, I hitched a jump seat ride in an Eastern DC9-10 from JAX to MIA with a couple of Navy trained Eastern pilots, both still active in the reserves, and both former "mustangs". Our flight profile (not the standard filed flight plan) was a max rate climb to FL260, 50 miles NE of Orlando, then a flight idle descent into MIA. It was late at night, we were high on the approach profile, traffic was dead, and the crew talked the controller (another ex-squid) into letting us do a high altitude military style teardrop penetration approach (not a peep from the cabin, just snores). The power levers stayed at idle until it was time to dirty up for landing. Fuel burn beat the programmed number for the standard FL180 flight plan by 15%, and we beat the scheduled flight time by 7 minutes. That's how dramatic the altitude difference is with turbines.
> One of my buddies from the flying club taxied up to the gate as we were deplaning about 0100 (on to the tarmac; jetways all occupied by morning departures), and got me back to NQX in time to catch a few winks before morning muster.
> Biff, Flieger, and any other active airline pilots out there, that was nearly fifty years ago, and rules were a tad different then. I even got my Commercial and CFI without an Instrument Rating at first. Had to upgrade in 1975.
> ...



Wes,

My first half of Undergraduate Pilot Training was in the mighty Tweet, AKA the T-37. It was a huge part of instrument flying to regularly do the dreaded teardrop penetrations that your DC-9 friends so readily demo’d. I didn’t mind doing them but they are much more demanding than radar vectors to the ILS / visual.

From what I understand the penetration approach was designed for the early jets which had tremendously short legs or very high fuel burns. It allowed for an almost entirely flown in idle descent approach and the navaid was usually on the destination airfield. The Tweet was a fairly early jet.

We even did them in the T-38 which could be a handful as it required a bit quicker thinking and much greater lead turns (for level off or turns from an arc to a radial or vice versa). Penetrations were flown at 300kias (Eagle at 350kias until entering the pattern / downwind) with a Tacan, DME and an ILS. Flight director only for the ILS for both a/c.

KROW HI-ILS OR LOC RWY 21 (IAP) ✈ FlightAware

This one was called the Widow Maker. You would sign the wall under the “I beat it” or “It beat me” areas in the FBO. Yes, that Roswell from little green men fame.

Cheers,
Biff

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## CORSNING (Jun 1, 2019)

taly01 said:


> 2) Handling of Ki-44 was much more difficult than Ki-43/61 both in flight and especially landing for new pilots.
> 
> *From Aircraft of the Aces 100 by Osprey page 16:
> "The Ki-44 was at first restricted to pilots with at least 1000 hours of flying
> ...

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## CORSNING (Jun 1, 2019)

taly01 said:


> 1) Range for Ki-44 was much less than Ki-43/61, and in the South Pacific range is king,
> *Agreed.*
> 
> *Ki.44-II: 740 ml/174 mph/128 g internal fuel, 1,050 ml/166 mph/197 g w/drop tanks.
> ...

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## XBe02Drvr (Jun 2, 2019)

BiffF15 said:


> From what I understand the penetration approach was designed for the early jets which had tremendously short legs or very high fuel burns. It allowed for an almost entirely flown in idle descent approach and the navaid was usually on the destination airfield.


On weekends when they weren't doing syllabus hops, the F4 and A4 guys would go out and do penetrations over the field from 20K. Unrestricted climb followed by a "dead stick" (flight idle and just enough "boards out" to compensate for the residual thrust) teardrop approach to a touch and go and do it all again. An F4 could manage just about 4 reps on internal fuel; an A4 could just about squeak out 5. We never had to wait for Navy Day or the 4th of July for an airshow; between the Grim Reapers and the Beaufort Harriers, we had an airshow most weekends. But for those hapless mid shift workers who had to sleep in the daytime, it was an unholy PITA.
Cheers,
Wes
PS: OMG, that Roswell approach is one busy SOB! If you're in a Talon, you're category E, right? Way busier than the basic teardrop. The roll in to the localizer's got to be bear at Talon speeds. Peg the needle and go missed. There's no saving it at that point. With circling minimums that high, there must be high terrain nearby.

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## XBe02Drvr (Jun 2, 2019)

BiffF15 said:


> The Tweet was a fairly early jet.


Wasn't it the last jet to enter service with centrifugal compressor engines? That J69 is a cute little kerosene powered siren. We had a Tweet drop in at our field with a powerplant casualty when I was working in the shop at the commuter. It sat over at the Air Guard for several days waiting for the AF to fly in a new engine and a engine change crew. The Air Guard offered to do the work, but the pilot, a fresh out of UPT FAIP with a shiny butterbar, said he was not allowed to let weekend warriors touch his bird. So stated, as he gazed longingly at the F16s being upgraded to a later block configuration. Some of my fellow mechs were in the Guard, so when we went on our midrats break, we would stop over and check progress on the Tweet. For what should have been a simple operation, it sure took long enough. The crew they flew in were a bunch of young kids led by an E6 who looked like he belonged in high school.
The Tweet pilot hung around for days with nothing to do and bemoaning his fate. Seems he had his heart set on being a fighter pilot, but instead they made him an instrument instructor and sent him around to do proficiency rides with senior officers who were aviators but assigned to non-flying billets. Not a particularly ego-gratifying activity.
Cheers,
Wes

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## BiffF15 (Jun 2, 2019)

XBe02Drvr said:


> Wasn't it the last jet to enter service with centrifugal compressor engines? That J69 is a cute little kerosene powered siren. We had a Tweet drop in at our field with a powerplant casualty when I was working in the shop at the commuter. It sat over at the Air Guard for several days waiting for the AF to fly in a new engine and a engine change crew. The Air Guard offered to do the work, but the pilot, a fresh out of UPT FAIP with a shiny butterbar, said he was not allowed to let weekend warriors touch his bird. So stated, as he gazed longingly at the F16s being upgraded to a later block configuration. Some of my fellow mechs were in the Guard, so when we went on our midrats break, we would stop over and check progress on the Tweet. For what should have been a simple operation, it sure took long enough. The crew they flew in were a bunch of young kids led by an E6 who looked like he belonged in high school.
> The Tweet pilot hung around for days with nothing to do and bemoaning his fate. Seems he had his heart set on being a fighter pilot, but instead they made him an instrument instructor and sent him around to do proficiency rides with senior officers who were aviators but assigned to non-flying billets. Not a particularly ego-gratifying activity.
> Cheers,
> Wes



Wes,

What year was that? I went through in 1988-89 and we had contract MX at Vance AFB. I went through AT-38s at Holloman AFB immediately following and they were contract as well (mostly ex USAF).

It’s not unusual for one unit to not let another do work on their jets. In the Eagle when going cross country you usually made every other stop at another F15 base so the jet could get some love from someone familiar with the type. I would often hit Sheppard AFB as well which is where they make Eagle Crew Chiefs.

Cheers,
Biff

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## XBe02Drvr (Jun 2, 2019)

BiffF15 said:


> What year was that?


In the winter of 1984/85, I forget the exact date. The Air Guard had just traded in their F4Ds for some 1st generation F16s which needed to be upgraded before they could go on line. They did that so swiftly and efficiently that USAF started sending other units' birds to them for upgrading. They had an experienced and mature maintenance force with a lot of retired career NCOs working there full time (not your average weekend warrior outfit), and became a designated F16 upgrade center, as they had been for the F4, EB57, and F89 previously.



BiffF15 said:


> It’s not unusual for one unit to not let another do work on their jets.


If that Tweet had contract maintenance at home, I suppose the contractor would be a little leery as to who was going to fiddle with his jets. OTOH, that bunch of kids they sent to do the engine swap looked pretty military to us. A band of 2 and 3 stripers on a shop floor where almost everyone was wearing 5 or more. The old timers labeled them (privately) as "the Keystone Kops" and intervened only once, to prevent what could have been a serious injury.
The Guard even had access to up to date tech pubs on all USAF active aircraft types, and were able to supply an update on the Tweet that the kids were unaware of.
I think it's time to get back to Tojo and Jack (sound like a 1980s cop show?), don't you?
Cheers,
Wes

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## taly01 (Jun 3, 2019)

From reading Jiro Horikoshi (who designed A6M and J2M) Zero data book he had a note ...although A6M5 was planned as last Zero, production had to increase due to Raiden problems.....seemed strange and wrong to me. But reading more information from the Japanese sources the Raidan WAS planned to substantially replace the Zero. However over 1943/44 the early production Raiden had some hard to solve resonance failures, and at this time the N1K1-J was almost ready for production, and in comparative trials the N1K1-J easily outmaneouvered the J2M3 and had much longer range. 

So the J2M3 production almost stopped in early 1944 and N1K1-J was put into priority production, however by the time all this had happenned the Homare engine in the N1K1-J was quite unreliable in service and also had undercarriage faults and other design flaws. Meanwhile the vibration resonance had mostly been solved in the J2M by new engine mounts and new thicker propeller blades.






Then they found the Raiden was one of the best B-29 intererceptors and tried to bring as many as possible into new specification but only ~600 ever made. Definately unique design!

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## Ivan1GFP (Jun 3, 2019)

Ivan1GFP said:


> The J2M3 sometimes had broad blade propellers installed, but the one that was tested did not have those.
> They can be recognized by corners at the root of each propeller blade. I don't know if that difference would have improved speed, but I would expect that a bigger propeller would not have been installed if it didn't help anything.



Just some photographs for a comparison.

- Ivan.

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## DarrenW (Sep 17, 2020)

CORSNING said:


> J2M3 m21 vs. P-47N.
> The following quote is from page 53 of Erik Pilawskii's 'Fighter Aircraft
> Performance of WW2'.
> " The J2M3 was remarkable for its tremendous flying horsepower, possessing
> ...



Mr. Pilawskii's view is very simplistic and doesn't take into effect the strategic situation in which the two aircraft were forced to operating within. From late 1944 onward, the J2M was almost exclusively employed within the Japanese home Islands as a point defense interceptor, making the J2M's primary opponents the high flying B-29s and their escorts. The overall performance of the J2M wasn't stellar at these heights, and when pitted against aircraft such as the P-47N it suffered accordingly. His statement concerning the overall inferiority of the P-47N is a difficult pill to swallow, given the fact that it exceeded the performance of the Japanese aircraft in practically every metric at these altitudes, with the possible exception of climb rate.

I am also under the impression that the performance numbers given in the TAIC reports for the 'Jack' were mere calculations. They apparently used an incorrect propeller efficiency which gave overly optimistic results. Flight testing was only performed in order to discovery basic flight characteristics and the airplane was never pushed to any real limit.

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## Ivan1GFP (Sep 17, 2020)

Hello DarrenW,

Regarding the altitudes at which the P-47N and the J2M3 might have met, I would pretty much disregard anything past about 8000 Meters.
The B-29s did initially bomb from higher altitudes but found that bombing from the Jetstream wasn't doing good things for accuracy and later bombing missions were from much lower altitude.

Another thing to keep in mind is that the P-47M/N didn't have very good initial acceleration. Being able to get to 460 MPH might be cool, but being able to recover energy after maneuvers is also a great tactical advantage and the J2M wins in that regard. Climb rate and acceleration are both an indication of surplus power.
Regarding my claim about initial acceleration, look for the stories about "Wonderful Winnie", a P-47M in the ETO, whose pilot raced P-51Ds and won.
Initially they would leave him behind, but EVENTUALLY he would catch up and overtake them.

With regard to propeller efficiency, one has to wonder about how poor Japanese aeronautical engineering really was if they could not build a good propeller for an engine that was in production for quite some time before the J2M came along. The Kasei had been in service in bombers for a long time and inefficient propellers would have cost them range which would not have been acceptable.
It also matters at what speeds a propeller is efficient or inefficient.

- Ivan.

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## GregP (Sep 17, 2020)

One thing about the radien most people don't remark on until they see it up close and in person is the size of the cockpit. It is huge. A Japanese pilot could probably take evasive action by jumping around inside the cockpit!





Here is a side view of the Planes of Fame Raiden. The lower wheel covers had not yet been fitted after a paint job. The fellow walking in front is John Maloney of the Planes of Fame. He painted the Radien and did a lot of touch-up sheet metal repairs.

Here are the lower wheel covers after they were fitted:





Here is the tailwheel:





All for now.

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## Shortround6 (Sep 17, 2020)

You can make a very good bomber propeller, that doesn't mean it will be a good fighter propeller and vice versa.

For instance Lancasters used 3 blade 13 ft propellers. Try sticking that on a Spitfire or Hurricane

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## taly01 (Sep 18, 2020)

It would have been interesting if they made a "short-nose" J2M, without the 3ft extension shaft and cooling fans, the extension shaft/fans may have caused some of the vibration problems, and the cooling fans robbed some 80hp+ from engine, probably close to that lost by air drag from a blunter nose. The failed service introduction of the J2M was a disaster almost up with the Helldiver SB2C, and Me210, that should have had a more radical response.

The small diameter nose does seem to have let them use quite a small diameter propeller? A larger cowl would have meant a larger propeller.

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## BiffF15 (Sep 18, 2020)

taly01 said:


> It would have been interesting if they made a "short-nose" J2M, without the 3ft extension shaft and cooling fans, the extension shaft/fans may have caused some of the vibration problems, and the cooling fans robbed some 80hp+ from engine, probably close to that lost by air drag from a blunter nose. The failed service introduction of the J2M was a disaster almost up with the Helldiver SB2C, and Me210, that should have had a more radical response.
> 
> The small diameter nose does seem to have let them use quite a small diameter propeller? A larger cowl would have meant a larger propeller.



Taly,

I don't follow your comments regards prop size compared to cowl size. Why would a larger cowl allow for a larger prop? I thought the limitation was usually for prop clearance to prevent ground strikes?

Cheers,
Biff


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## Ivan1GFP (Sep 18, 2020)

Shortround6 said:


> You can make a very good bomber propeller, that doesn't mean it will be a good fighter propeller and vice versa.
> 
> For instance Lancasters used 3 blade 13 ft propellers. Try sticking that on a Spitfire or Hurricane



Hello Shortround6,

Agreed, but keep in mind that Kasei was used in not just big multi engine bombers. There were relatively small twins and single engine aircraft using the same engine.....

- Ivan.


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## XBe02Drvr (Sep 18, 2020)

BiffF15 said:


> Taly,
> 
> I don't follow your comments regards prop size compared to cowl size. Why would a larger cowl allow for a larger prop? I thought the limitation was usually for prop clearance to prevent ground strikes?
> 
> ...


I think he meant *would require* a larger prop. A larger cowl would direct more of the prop's wash into engine cooling, reducing the disc area devoted to propulsive thrust. The only way to regain that area would be to increase blade length, unless you want to totally redesign the prop, which it appears they did. Upthread there was mention of a "paddle blade" prop with "notches" in the blade roots. This is the classic silver bullet approach to gain more thrust *and* more cooling flow from the same horsepower without increasing diameter, but faces some major challenges in material strength and harmonic vibration. Comparable to the US P47 prop upgrade.

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## DarrenW (Sep 18, 2020)

Ivan1GFP said:


> Another thing to keep in mind is that the P-47M/N didn't have very good initial acceleration. Being able to get to 460 MPH might be cool, but being able to recover energy after maneuvers is also a great tactical advantage and the J2M wins in that regard. Climb rate and acceleration are both an indication of surplus power.



Hi Ivan,

Actually, I am only assuming the J2M could out-climb the P-47N at these heights (due to it's excellent reputation for climb). However, having only TAIC calculations to turn to above 20,000 feet, I wouldn't be able to say with any degree of confidence that it actually could.

I'm also not sure that above critical altitude the J2M could out-accelerate the P-47, as the turbocharged American fighter maintained sea-level horsepower close to 30,000 feet, in return probably giving it a better power-to-weight ratio at these higher altitudes.



Ivan1GFP said:


> With regard to propeller efficiency, one has to wonder about how poor Japanese aeronautical engineering really was if they could not build a good propeller for an engine that was in production for quite some time before the J2M came along.



I never said the propeller was of poor quality, just that the Americans were assuming a higher efficiency when calculating performance figures for the type. According to Jiro Horikoshi the J2M3 had a propeller of 0.74 efficiency, which is lower than the generally accepted 0.80 figure of the day.

And then there was the issue of propeller shaft vibration, which seems to have never really been fully understood or overcome. This must have had a negative effect on the actual engine thrust available at certain RPMs.

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## GregP (Sep 18, 2020)

The Planes of Fame could consider restoring their J2M3 to flying status. The problems included corrosion and the engine. Corrosion is fixable, but there is no other suitable engine that has an extended propeller shaft. So, only the original engine setup could be used. The main issue is the population of spare parts, which amounts to zero. 

As far as I know, there is no other extension shaft available for use in overhaul of the Kasei. It would be possible to make one, but that would require some serious funding that would only be reasonable if the airframe were to be overhauled, too. That means the entire project would have to be considered and likely funded or at least turned into a project before any work would begin, and the J2M is likely not that high on the priority list at this time. I'm guessing there, but we also aren't working on it, so the guess wouldn't seem to be all that far off.

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## XBe02Drvr (Sep 18, 2020)

XBe02Drvr said:


> This is the classic silver bullet approach to gain more thrust *and* more cooling flow from the same horsepower without increasing diameter, but faces some major challenges in material strength and harmonic vibration.


Imagine your "classic" slender variable pitch propeller blade before paddle blades came along. It tapers smoothly from a round cross section at the root to an airfoil of about the same cross sectional area at approximately the radius of the cowling, then assumes a progressive twist to keep the angle of attack constant across the radius at any rotational rate. Now with each power pulse this "tuning fork" flexes slightly, with the deflection distributed smoothly along its length like a fly rod in a cast, but increasing toward the tip as the cross section thins out. This is relatively easy to do with homogeneous materials and relatively simple harmonic tuning.
Now enter the designer who wants a prop to generate more cooling flow near its hub and dissipate more horsepower outside the cowl diameter without increasing blade count or overall diameter. Now we're looking at a robust (and stiff) wide chord twisted airfoil with likely squared, or nearly squared tips, and airfoil cross section extended nearly to the hub. No long smooth tapers here, and a sharp transition to a
round cross section at the hub (the "notches").
*Now*, what's happened to our tuning fork? It's become a stiff board with a hinge at one end, concentrating the bending action at the root and creating a huge metal fatigue issue. Some of this can be tuned out with mathematics that are beyond me, but it will almost certainly require exotic alloys and sophisticated manufacturing techniques.
You don't want to lose a blade in flight, as the resulting imbalance will likely rip the engine from its mounts or the mounts from the firewall, causing aircraft disintegration. It has happened. Not a fun day.

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## DarrenW (Sep 18, 2020)

The J2M was an innovative design which IMHO should have never been built. The R&D required took much needed time and resources away from the development of the A7M (which by all appearances looked to be an outstanding concept) and after a protracted delivery the JNAF ended up with a sub-par fighter at best. Luckily Kawanishi was hard at work with the N1K during this time, which at least gave them some measure of hope in maintaining control of their own skies, albeit with devastating consequences in the end.

I do find the approach used to the reduce frontal area with an engine equal in diameter to the R-2800 a very novel one, and like taly01 wonder what kind of performance and reliability would have been possible if Mitsubishi chose to stick with a more traditional engine layout.

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## GregP (Sep 18, 2020)

I disagree (see X above), but not in a bad way. I just like the Raiden but not enough to argue about it. Altogether a very nice airplane that COULD have been a high water mark had the engine and landing gear quality been better.

It's kind of like the Ta 152. The Ta 152 was not very effective since they basically only delivered 47 of them. But, one on one, they were amazing airplanes with impressive specs.

The Raiden was very good when it was running right. Some did, but not enough to matter all that much. Still, it is an impressive airplane in person and in the specs.

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## windhund116 (Sep 19, 2020)

Raiden had better armament. Four 20mm cannons. Especially against the B-29. Better high altitude ceiling, too.


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## Ivan1GFP (Sep 19, 2020)

DarrenW said:


> The J2M was an innovative design which IMHO should have never been built. The R&D required took much needed time and resources away from the development of the A7M (which by all appearances looked to be an outstanding concept) and after a protracted delivery the JNAF ended up with a sub-par fighter at best. Luckily Kawanishi was hard at work with the N1K during this time, which at least gave them some measure of hope in maintaining control of their own skies, albeit with devastating consequences in the end.
> 
> I do find the approach used to the reduce frontal area with an engine equal in diameter to the R-2800 a very novel one, and like taly01 wonder what kind of performance and reliability would have been possible if Mitsubishi chose to stick with a more traditional engine layout.



Hello DarrenW,

I am not entirely convinced that the A7M would have been a world beater had it actually been built. I believe the designers were counting on engines with the level of output that were never actually available and without them, that very large airframe would not have had any better performance than the typical late 1943 fighter. That wasn't going to be enough when there was such inferiority in numbers and pilot training.
As long as the aircraft remained a prototype and never entered production or service, it can remain "perfect".

Regarding propeller efficiency: As I stated before, it matters quite a lot at what speeds that efficiency is achieved. I have never actually done any significant calculations on the J2M to really understand how its engine and propeller under ideal conditions compare against comparable aircraft.
From flight evaluations, there WERE problems with vibrations at certain speeds, but in the test aircraft those speeds could easily be avoided.
Whether or not those aircraft were flown in tests for maximum speed, they were flown fast enough to test control response at quite high indicated airspeeds.
Sometimes one can find some pretty extraordinary and unexpected things when looking at the actual numbers such as when I did some poking around with specs of the Lockheed P-3 Orion.



XBe02Drvr said:


> Imagine your "classic" slender variable pitch propeller blade before paddle blades came along. It tapers smoothly from a round cross section at the root to an airfoil of about the same cross sectional area at approximately the radius of the cowling, then assumes a progressive twist to keep the angle of attack constant across the radius at any rotational rate.
> .......
> *Now*, what's happened to our tuning fork? It's become a stiff board with a hinge at one end, concentrating the bending action at the root and creating a huge metal fatigue issue. Some of this can be tuned out with mathematics that are beyond me, but it will almost certainly require exotic alloys and sophisticated manufacturing techniques.
> You don't want to lose a blade in flight, as the resulting imbalance will likely rip the engine from its mounts or the mounts from the firewall, causing aircraft disintegration. It has happened. Not a fun day.



Hello XBe02Drvr,

I believe if the propeller blade were uniform thickness and construction, that would make sense, but many propeller blades are hollow which would affect some of those uniform vibrations. Another possibility is to increase the thickness of the "paddle blade" as it gets closer to the hub. The relative airflow will be much slower, so there doesn't need to be quite the same thin section as needed at the tip.
One of the very interesting things about the propellers on the P-47 from what I have seen in some performance comparisons is that although the "Paddle Blades" were more efficient at low airspeeds, they were not quite as efficient as the original "Toothpick" propellers at high speed and there was a significant difference between the fairly common Curtiss-Electric Asymmetrical Paddle Blade and the Hamilton Standard Paddle Blade with the H-S being a bit better at high speed. There were at least two different kinds of paddle blade propellers made by each manufacturer.

- Ivan.

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## GregP (Sep 19, 2020)

I've seen NTSB reports on hollow blades that had corrosion failures in flight an lost blades in cruise or climb. None of them were pretty and none were survivable. All the report I saw were from twin turboprop small airliners, and none survived. When I say "hollow," I don't mean absolutely hollow, but a hollow aluminum blade with rubber-like filling in the hollow.

All the blades that failed had some sort of impact around the hub that was never dressed or looked at very hard. All experienced some vibrations never before felt before failure.

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## DarrenW (Sep 19, 2020)

GregP said:


> I disagree (see X above), but not in a bad way. I just like the Raiden but not enough to argue about it. Altogether a very nice airplane that COULD have been a high water mark had the engine and landing gear quality been better.
> 
> It's kind of like the Ta 152. The Ta 152 was not very effective since they basically only delivered 47 of them. But, one on one, they were amazing airplanes with impressive specs.
> 
> The Raiden was very good when it was running right. Some did, but not enough to matter all that much. Still, it is an impressive airplane in person and in the specs.



Besides a better than average climb rate at medium altitudes, what was so "impressive" about it's performance? The J2M was the least favored of the late-war Japanese fighters, with many pilots commenting that it lacked the handling and maneuverability to successfully dogfight with a Mustang or Hellcat. They also disliked the very high landing speed (138 mph) and poor forward visibility. Pilots had to be proficient at dead sticking the plane as engines seized so often. When given the choice some even reverted back to the older but trusty Zero. Only a seasoned pilot like the eccentric Sadaaki Akamatsu had any words of praise for it. 

TAIC pilots rated the performance of a captured example as "good", which to me is a far cry from being "impressive".


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## CORSNING (Sep 19, 2020)

*TAIC pilots rated the performance of a captured example as "good", which to me is a far cry from being "impressive".[/QUOTE]*

Darren, sometimes "good" is a good thing.

*Technical Air Intelligence Command*
The captured fighter (J2M3) was tested by the senior pilot attached to TAIC who had flown virtually every
Allied fighter, as well as the Messerschmitt Bf 109, the Focke-Wulf Fw 190, and such Japanese types as the
Nakajima Ki-43 Hayabusa and Ki-84 Hayate, the Kawasaki Ki-45 Toru and the Mitsubishi A6M Zero-Sen.
After logging three hours and twenty minutes in the Raiden *he stated unequivocally that it was the best Japanese fighter that he had flown*, offering a good performance, good stability, good stalling charateristics, and good take-off and landing qualities.
Good Features:
1. Good stability.
2. Good stalling characteristics.
3. Comfortable cockpit.
4, Good take-off and landing qualities.
5. Good overall performance.
6. Maneuver flaps.
Bad Features:
1. Brakes and rudder brake action poor.
2. Heavy ailerons and lack of maneuverability at high speeds.
3. Low mechanical reliability.
4. Short range.

Note about the maneuver flaps from Air Enthusiast July 1971 Vol.1, No.2.
Page 103: Rolls, Immelmans and turns are executed with ease at normal speeds, although ailerons are 
heavy at all operating speeds. and the aircraft cannot be rolled as rapidly as a P-51 (Merlin).
Maneuver flaps of Fowler type are fitted, and are controlled by a safety switch and trigger on the stick.
These are extended only when the trigger is depressed and retracted immediately when the trigger is 
released, and their operation is superior to any used on our (US) aircraft.


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## GregP (Sep 19, 2020)

Funny you should say the landing speed was 138 mph since the design specification was that landing speed be no higher than 81 mph and it met the specs.

The J2M-3 (most-produced: 435 built) hit 370 mph and had a 360° turn time of 18 seconds (speed not specified), which is right in there with a Yak-3, widely regarded as the best turner in modern WWII fighters. The J2M-1 (8 built) turned in 16 sec and the J2M-2 (141 built) turned in 17 seconds. A Hellcat could not match 18 seconds and neither could a Mustang. Really. A Messerschmitt Bf 109G was 22.6 - 22.8 sec. A Mustang I was 23 sec. 

It had two 20 mm cannons and two 30-cal MG, which is effective enough considering the number of Allied aircraft shot down by that exact combination, which is ... like ... almost all of them in the Pacific Theater.

I have been in the cockpit and the forward visibility is not bad at all compared with a Mustang or a Hellcat. I have a great pic of the visibility but have been asked not to post cockpit pics, so I won't. But the visibility is quite good.

Not sure where you are getting all your objections, but the only ones that seen true to me are engine and landing gear problems.


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## DarrenW (Sep 19, 2020)

CORSNING said:


> Darren, sometimes "good" is a good thing.



Lol yes you're absolutely right Corsning, especially when one of those ratings could have easily been considered "bad". Oh well. So I guess that the Japanese, unlike the Americans, didn't know a "good" thing when they saw it and decided to go with other designs instead....to their determent of course.

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## DarrenW (Sep 19, 2020)

GregP said:


> Not sure where you are getting all your objections, but the only ones that seen true to me are engine and landing gear problems.



My sources are:

_J2M Raiden and N1K1/2 Shiden/Shiden-Kai Aces_ (Izawa/Holmes) and _Imperial Japanese Navy Aces 1937-45_ (_Sakaida_)


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## DarrenW (Sep 19, 2020)

GregP said:


> It had two 20 mm cannons and two 30-cal MG, which is effective enough considering the number of Allied aircraft shot down by that exact combination, which is ... like ... almost all of them.



I didn't bring up armament but now that you have do you happen to have statistics concerning the actual victory count for the J2M series using these cannons?


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## GregP (Sep 19, 2020)

Then some source is very wrong. 138 mph is about 119 knots and that is Lockheed T-33 speeds for landing, not Radien speeds. Ditto the rest. What you are saying just isn't right.

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## DarrenW (Sep 19, 2020)

GregP said:


> Then some source is very wrong. 138 mph is about 119 knots and that is Lockheed T-33 speeds for landing, not Radien speeds. Ditto the rest. What you are saying just isn't right.



I never flew the airplane so all I have is my source material to go by. Much of what is in these books are eyewitness testimonials which were given to the respective author. If any of the material is incorrect than it can most likely be traced back to a Japanese pilot or ground crew member.

If you're saying it had a landing speed similar to a WWII carrier aircraft then who am I to disagree with you...but feel free to throw another red X my way if it makes you feel any better.


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## DarrenW (Sep 19, 2020)

GregP said:


> The J2M-3 (most-produced: 435 built) hit 370 mph and had a 360° turn time of 18 seconds (speed not specified), which is right in there with a Yak-3, widely regarded as the best turner in modern WWII fighters. The J2M-1 (8 built) turned in 16 sec and the J2M-2 (141 built) turned in 17 seconds. A Hellcat could not match 18 seconds and neither could a Mustang. Really. A Messerschmitt Bf 109G was 22.6 - 22.8 sec. A Mustang I was 23 sec.



What is your source for these numbers? I'm not trying to be difficult, just interested is all.


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## Shortround6 (Sep 19, 2020)

Just throwing this out there.
Sometimes stalling speed, landing speed and _approach_ speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.

P-40D/E had an approach speed of 90mph at 8400lbs even though stall speed was in the 70s. 
Throw in a bad translation that confuses mph with knots and we get 166,6kph and turn that back to MPH and we get an approach speed of 103 mph 

Or just bad proof reading/typo.

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## DarrenW (Sep 19, 2020)

Shortround6 said:


> Just throwing this out there.
> Sometimes stalling speed, landing speed and _approach_ speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.
> 
> P-40D/E had an approach speed of 90mph at 8400lbs even though stall speed was in the 70s.
> ...



Excellent observation thanks for the insight.


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## taly01 (Sep 20, 2020)

The Kasei 20 series engine was water injected and there was "rough" running troubles getting the water injection right on both G4M and J2M, it is possible the frequency of the rough engine running matched critical vibration speeds of J2M propellor/shaft, until they changed the prop which removed the failure cause, but not roughness.



> Now enter the designer who wants a prop to generate more cooling flow near its hub and dissipate more horsepower outside the cowl diameter without increasing blade count or overall diameter. ..........................It's become a stiff board with a hinge at one end, concentrating the bending action at the root and creating a huge metal fatigue issue.



This reminds me of the confusion I have over cuffed propellors, I assume they were seperate to the prop blades so they could be sized for engine cooling requirements, 







but then I see pictures of P-51 with cuffed blades? What cooling is needed there!

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## GregP (Sep 20, 2020)

Hi DarrenW,

A red X is not a negative, it means "I disagree." Agreement and disagreement are the basis of discussion.

There weren't many WWII carrier planes with a landing speed of 81 mph. Most were slower.

I have not posted any "flame attempts" or said anything about you personally. The specs on the J2M I can find simply don't match what you've posted and I have the rather unique opportunity to see one live anytime I want to. Perhaps that makes a difference to me, but the J2M-3 seems like a pretty good fighter from all I can find, and that is backed up by a Planes of Fame Museum member from Japan.

I have no dog in this hunt. I just like the Raiden and you don't seem to. There is absolutely nothing wrong with either opinion.

Let's try a calculation. A basic wings-level stall speed should be about: Vs = 17.2 * square root (W / (CLmax * sigma * S)), where Vs = stall speed in knots, W = weight, CL max = max lift coefficient, sigma = altitude density ratio, and S = wing area (sq ft). Let's try sea level, 7,077 lbs combat weight, 215.8 sq ft wing area, sigma = 1 at sea level ... and I'll go with CL max = 1.5 for a decent WWII fighter wing average. It could be better. Calculated stall speed without flaps using the above formula is 80.4 knots TAS, making the flaps down stall speed of 81 mph in the specs look pretty darned close. And, it's a far cry from 138 mph. Let's say the flaps aren't very good and drop the stall speed by only 5 knots. That puts it at 75.4 knots or 86.7 mph. Considering I don't have the real CL max, I'd believe the 81 mph any day. If the real CL max goes to something like 1.65, the flaps-up stall speed calculates to 76.7 knots. The real number SHOULD be somewhere around 1.45 - 1.65, I can't say where it actually falls.

The J2M is rather widely regarded as a pretty good fighter when it was operating correctly.

We don't have to agree on the Raiden. There is only one left, and it isn't flying at this time. So, we just disagree on its merits. No biggie. Cheers to you.

Several sources: I can find the wing area at: Mitsubishi J2M Raiden (Jack) Info or any number of websites. Try: Mitsubishi J2M Raiden (Thunderbolt) 'Jack' , too, for number produced and Mitsubishi J2M Raiden - Specifications - Technical Data / Description, too. I also have a book, "Japanese Aircraft Performance and Characteristics," written by Ed Maloney, founder of the Planes of Fame. His quoted specs come straight from TAIC. I have other books, but they say the same things.

Cheers again.

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## DarrenW (Sep 20, 2020)

GregP said:


> Hi DarrenW,
> 
> A red X is not a negative, it means "I disagree." Agreement and disagreement are the basis of discussion.
> 
> ...



Sorry Greg, I didn't mean to turn this into an emotional debate for you. The points I've made have nothing to do with liking or not liking the aircraft. I find it fun to talk about old airplanes and that's really the size of it. I have my sources and you have yours and obviously they don't agree. We can leave it at that. 

Lastly, you seem to be hung up on stall speed but Shortround pretty much explained some very plausible reasons for the discrepancy. I'm satisfied if you are.

Cheers to you as well.....

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## Ivan1GFP (Sep 20, 2020)

DarrenW said:


> Besides a better than average climb rate at medium altitudes, what was so "impressive" about it's performance? The J2M was the least favored of the late-war Japanese fighters, with many pilots commenting that it lacked the handling and maneuverability to successfully dogfight with a Mustang or Hellcat. They also disliked the very high landing speed (138 mph) and poor forward visibility. Pilots had to be proficient at dead sticking the plane as engines seized so often. When given the choice some even reverted back to the older but trusty Zero. Only a seasoned pilot like the eccentric Sadaaki Akamatsu had any words of praise for it.



Hello DarrenW,

The problem with some of these pilot opinions is that they may be the result of the "Culture" of how they were trained.
If you have the book about Mitsubishi Zero by Robert Mikesh (Motorbooks), it gives a pretty good account of some discussion that went into the design requirements for the A6M:
Two very experienced fighter pilots had vastly differing views on requirements for speed versus maneuverability.
Genda preferred Maneuverability.
Shibata preferred Speed and argued that pilot training could compensate for shortcomings in maneuverability.
Genda won the argument and we know how short the effective life span of the resulting A6M design was as a result.
By the end of the war, Shibata was proven correct, but there were probably still quite a few pilots left who had the same opinion as Genda did.

When compared to the A6M or Ki 43 in a low speed fight, nothing else is going to be that close.
Keep in mind that the Japanese also had the opportunity to test the Me 109E and the FW 190A and didn't like either one.

How would these same Japanese pilots have liked the Corsair, Yak-3, or La-5FN? Does it mean that those were inferior fighters to the A6M or just that the pilots doing the evaluations were not accustomed to the style of fighting that those aeroplanes required?

- Ivan.

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## Ivan1GFP (Sep 20, 2020)

Shortround6 said:


> Just throwing this out there.
> Sometimes stalling speed, landing speed and _approach_ speed get confused or badly translated. Stalling speed especially is affected by weight but so are the other two.
> .......
> Or just bad proof reading/typo.



Hello Shortround6, 

I believe we ran into the same problem a while back in a translated manual for the Ki 43 in which speeds in KPH were mistaken for MPH with some resulting numbers that looked OK at a glance but made no sense in physics.

- Ivan.


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## GregP (Sep 20, 2020)

Cheers DarrenW. It's all good.

I'm not hung up on stall speed. It is just tough to wrap my head around a 7,000 pound fighter supposed to have a landing speed higher than a B-26 Marauder.

I surely wish we had more voluminous information about Japanese warbirds. Alas, we seem to have to make due with a few bits of information that vary among sources, sometimes rather widely. I like the late-war Japanese fighters including the Ki-84, J2M, N1K, and Ki-100. I could include the Ki-44, too. They aren't collectively especially fast but climbed well and were enough to give most Allied fighters a run for their money.

Of these, the Raiden would seem to have the most quality issues.


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## DarrenW (Sep 20, 2020)

Ivan1GFP said:


> Hello DarrenW,
> 
> The problem with some of these pilot opinions is that they may be the result of the "Culture" of how they were trained.
> If you have the book about Mitsubishi Zero by Robert Mikesh (Motorbooks), it gives a pretty good account of some discussion that went into the design requirements for the A6M:
> ...



True, but it's no coincidence that the IJNAF ultimately chose the _Shiden/Shiden-Kai_ series as their primary interceptor-fighter. In that decision the opinions of front-line pilots/ground crews were relied heavily upon, probably just as much as the technical side of the equation. My sources conclude that pilots continually complained about it's lack of performance, which only got worse as weight increased with the addition of both heavier armor and armament.


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## DarrenW (Sep 20, 2020)

GregP said:


> Cheers DarrenW. It's all good.
> 
> I'm not hung up on stall speed. It is just tough to wrap my head around a 7,000 pound fighter supposed to have a landing speed higher than a B-26 Marauder.
> 
> ...



Good, I'm glad we have come to a sense of understanding. 

On another note there is something related to the J2M3 at Planes of Fame that has me puzzled. Why are the tail markings consistent with a _Raiden _assigned to 302nd _Kokutai_, while the fuselage is adorned with lightning bolts that are often associated with the 352nd _Kokutai_? Is it supposed to be a hybrid of sorts in order to represent both units?


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## Ivan1GFP (Sep 20, 2020)

DarrenW said:


> True, but it's no coincidence that the IJNAF ultimately chose the _Shiden/Shiden-Kai_ series as their primary interceptor-fighter. In that decision the opinions of front-line pilots/ground crews were relied heavily upon, probably just as much as the technical side of the equation. My sources conclude that pilots continually complained about it's lack of performance, which only got worse as weight increased with the addition of both heavier armor and armament.



Hello DarrenW,

I believe the choice of the N1K2-J over J2M was for different reasons and is a different argument altogether.
Assuming a J2M was in good running order, it was a pretty good interceptor. It was not a good general purpose fighter because it had no range.
As for weight increases with additional armour and armament there were obviously differences between J2M3 and earlier models, but there really weren't any other significant changes during the rather short production run other than attempts with installing different variations of the Kasei engine with and without turbochargers. The only really significant armament change between J2M2 and J2M3 with the cowl MG being replaced by an additional pair of wing cannon.

The preference of Japanese pilots for N1K2 over J2M probably also goes back to the culture situation I described earlier though in this case the overall straight line performance wasn't that different. They just aren't going to like a fighter that doesn't maneuver as well.
The quality of N1K2 versus J2M wasn't really the subject of this thread in any case. The bottom line was that NEITHER aircraft was reliable in service though both had great potential if everything was working correctly which usually was not the case.

- Ivan.


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## GregP (Sep 20, 2020)

Hi DarrenW,

I do not know about the chosen paint scheme for our J2M-3, but most of our aircraft are painted in the schemes of actual combat aircraft. Next time I see him, I'll ask John Maloney. He painted it.


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## DarrenW (Sep 21, 2020)

Ivan1GFP said:


> I believe the choice of the N1K2-J over J2M was for different reasons...





Ivan1GFP said:


> The bottom line was that NEITHER aircraft was reliable in service though both had great potential if everything was working correctly which usually was not the case.



Hi Ivan,

I disagree with the first statement and agree with the second, but as you stated the topic of the thread doesn't include the Kawanishi fighter so there's no need to discuss it any further here.


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## cherry blossom (Sep 23, 2020)

I have spent some time reading Wikipedia and I wondered if anyone else has noticed that the designs of the Ki-44 and the J2M represent different philosophies. The Ki-44 is rather typical of its generation of Japanese fighters in being very lightly constructed and in lacking armour. However, if we want to find fighters with a similar wing, our best comparisons are the Yak-3, wingspan 9.2 m (30 ft 2 in) and wing area 14.85 m2 (159.8 sq ft), and the original prototypes of the Fw 190, wingspan 9.5 m (31 ft 2 in) and wing area 15.0 m2 (161 sq ft). The Ki-44 II had a wingspan of 9.45 m (31 ft 0 in) and a wing area of 15 m2 (160 sq ft). The Ki-44 with an empty weight of 2,106 kg (4,643 lb) is even lighter than the Yak 3 which has an empty weight of 2,346 kg (5,172 lb). The Fw 190 was designed as a "cavalry horse" and even the v1 weighed 2,768 kg (6,103 lb) whilst an A3 of 1942 weighed 2,900 kg (6,393 lb) empty. As expected from the weights, the Ki-44 climbs best, reaching 5,000 m (16,404 ft) in 4 minutes 17 seconds, whilst Yak-3 can climb to 5,000 m (16,404 ft) in 4 minutes 30 seconds. The Fw 190A3 presumably using a derated engine in November 1942 (just after the Ki-44 II had entered service) takes about 6 minutes to reach 5,000 m http://www.wwiiaircraftperformance.org/fw190/fw190-a3-sheet-26-11-42.jpg as does the La-5.

If we look at maximum speeds, the RAE measurement of Faber's Fw 190A3 with a derated engine was 375 mph at 18,000 ft or an estimated 392 mph had the BWM been fully rated whilst Wikipedia gives the speed of the Ki-44 II as 605 km/h (376 mph, 327 kn) at 5,200 m (17,060 ft), presumably at "military" rating. The Yak-3's smaller and slimmer fuselage gives it a maximum speed of 646 km/h (401 mph, 349 kn) at 4,100 m (13,451 ft) but, of course, nearly two years later.

My tentative conclusion is that the Ki-44 could have been a terrifying if fragile opponent at low to medium altitude and that the USAAF over New Guinea was lucky that their opponents did not deploy it. Of course, the range was inferior to that of the Ki-43 and the Ki-61 and it is possible that Ki-44 had defects such as low Vne or a low rate of roll which have not been mentioned so far in this thread. However, there is no obvious reason why it should not roll rapidly and its acceleration should be the best in the world in late 1942.

By contrast, the J2M seems a typical non-Japanese fighter. The wing area, 20.05 m2 (215.8 sq ft), is almost the same as the Ki-61 or Ki-100 and falls in the middle of the Italian 5 Series being just less than the Re 205's 20.4 m2 (220 sq ft). The empty weight of 2,839 kg (6,259 lb) is heavier than any of those aircraft and close to that of the Fw 190 A3. The larger wing means that the J2M3 climbs to 6,000 m (19,685 ft) in 6 minutes 14 seconds compared to 7.6 minutes for the Fw 190 A3 (note that the J2M3's contemporary the Fw 190 A8 climbed slower due to extra armament and armour and the Raiden could even beat the Fw 190 D9 to 6,000 m). In the thread N1K2-J Shiden-Kai Performance Laurelix argues convincingly that a Shiden could climb quicker if everything was working and this probably caused the IJNAF to prefer it. However, the Shiden's Homare didn't always give the expected power and thus the J2M was the best Navy fighter for attacking B-29s at high altitude.

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## windhund116 (Sep 23, 2020)

Certain versions of the J2M had four 20mm cannons, right? This made it as potent as the Kawanishi N1K Shiden. I'd imagine those 20mm cannons would make those planes more lethal against the B-29s.


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## Greg Boeser (Sep 23, 2020)

cherry blossom said:


> My tentative conclusion is that the Ki-44 could have been a terrifying if fragile opponent at low to medium altitude and that the USAAF over New Guinea was lucky that their opponents did not deploy it. Of course, the range was inferior to that of the Ki-43 and the Ki-61 and it is possible that Ki-44 had defects such as low Vne or a low rate of roll which have not been mentioned so far in this thread. However, there is no obvious reason why it should not roll rapidly and its acceleration should be the best in the world in late 1942.


The USAAF in China certainly echoes your conclusion. When the first production aircraft began arriving in theater in early 1943 they gave the 23rd Fighter Group a nasty shock. The Ki-44 had a higher ceiling, better acceleration, a potent armament, excellent roll rate, and could stay with a P-40 in a dive.

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## TheMadPenguin (Sep 28, 2020)

Tojo? Jack? I'll take a Bearcat, please.


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## taly01 (Sep 29, 2020)

> Tojo? Jack? I'll take a Bearcat, please.


How about a Hellcat?







The Ki-44 seems to have been a reliable plane, deploying them to North East New Guinea in 1943-44 when the air bases were under heavy attack would have been a good use for them. Even if the landing strip needed was longer than Ki-43 they did fly bombers there so must have had some long strips available.

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## TheMadPenguin (Sep 29, 2020)

Before bearcats, I'll be happy with a hellcat.

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## GregP (Sep 29, 2020)

Though a very good choice, it would be tough to choose a Bearcat if you were in the IJN or IJA. 

You would likely be stuck with a Japanese aircraft. If that were to actually be the case, which would you choose?

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## cherry blossom (Sep 29, 2020)

I thought that it was quite interesting to imagine a Bearcat powered by the J2M's Kasei engine Japanese Zero vs Spitfire vs FW 190. It seems surprisingly simple to guess the performance because the Kasei's maximum power is quite close to the normal rating of the R-2800-30W. Thus F8F-2 Bearcat's maximum speed at normal rating, 363 knots (418 mph) at 22,000 ft, http://www.wwiiaircraftperformance.org/F8F/F8F-2_Standard_Aircraft_Characteristics.pdf, is probably close to what a Kasei powered Bearcat could achieve. It is harder to guess what a J2M5 could actually do and even harder to guess what a R-2800C powered Raiden could manage.

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## GregP (Sep 30, 2020)

They'd love to put an R-2800 of adequate outline in the Planes of Fame J2M-3, but there are no R-2800s with an extension shaft. It's OK to re-engine something like a Yak-3 / 9 because an Allison fits nicely and is available ... at least more available than a Mikulin or Kilmov, AND it doesn't look much different from a stock unit.

But putting an R-2800 in the J2M-3 would considerably alter its lines, making it a non-starter for a restoration to flight status project.

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## Kilkenny (Mar 18, 2022)

XBe02Drvr said:


> Unfair comparison! Like comparing an Emil to a Spit 14. Half a generation apart. How about a KI84?
> Cheers,
> Wes


Absolutely... The Ki-44 was flying in China in 1941; and could have been in service even earlier if IJA hadn't put so much attention on the Ki-43... The Raiden was a very sound design; if it had been given priority over all Homare-engined fighters (except the Ki-84), it could have been in service by the end of 1943 (and begun replacing the Ki-44)--- just in time to give the B-29 fits... In my opinion, the Japanese would have saved themselves a lot of grief if they just focussed all their warplane engine attention on the Kinsei and Kasei (and their 18-cylinder derivatives) and quickly phased out all the rest (and not started on the Homare) before they started the war!

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## GregP (Mar 18, 2022)

DarrenW said:


> I never flew the airplane so all I have is my source material to go by. Much of what is in these books are eyewitness testimonials which were given to the respective author. If any of the material is incorrect than it can most likely be traced back to a Japanese pilot or ground crew member.
> 
> If you're saying it had a landing speed similar to a WWII carrier aircraft then who am I to disagree with you...but feel free to throw another red X my way if it makes you feel any better.



What does THAT mean? If I do give a red X, all it means is "I disagree." Doesn't mean you're evil or anything. Really.


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## Wild_Bill_Kelso (Mar 18, 2022)

Greg Boeser said:


> AVG Tomahawks and RAF Buffalos were facing Ki-44s in December '41 and January '42.
> 14th AF P-40Es and Ks were dealing with Ki-44s in spring and summer of '43.
> After smacking Ki-27s and Ki-43s around, the Shoki came as a big surprise.
> The 23rd FG even felt that P-51As were no match for the Ki-44.


Do you have a source for this?



Greg Boeser said:


> When did the Jack have it's combat debut?

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## Greg Boeser (Mar 18, 2022)

Wild_Bill_Kelso said:


> Do you have a source for this?


For Ki-44s in Malaya and Burma, Shores' _Bloody Shambles._
For Ki-44s vs 23rd FG in 1943, Molesworth's _Sharks over China._

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## Wild_Bill_Kelso (Mar 19, 2022)

Greg Boeser said:


> For Ki-44s in Malaya and Burma, Shores' _Bloody Shambles._
> For Ki-44s vs 23rd FG in 1943, Molesworth's _Sharks over China._



Thanks, I thought I had all of Molesworth's books I didn't know that one though, I'll look for it.

Which volume of "Bloody Shambles" ?


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## Greg Boeser (Mar 19, 2022)

Volumes 1 and 2


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## Greg Boeser (Mar 19, 2022)

You might want to look at Osprey's_ Ki-44 "Tojo" Aces of World War Two _by Millman.

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## Wild_Bill_Kelso (Mar 19, 2022)

My pick would in fact be the Ki-44, simply because it was built and deployed in much greater numbers. So it actually had some impact on the war.

I'm not sure how much of a game-changer it was though, and I'm confused on a couple of points.

Somebody said the Ki-44 lacked armor and SS tanks? I thought it did have armor? 

The main fault seems to be that it was somewhat lightly armed, and didn't turn that well which can't have been popular with Japanese pilots. Is there any sense what Japanese pilots thought of it?

Considering how long it was in production, they didn't make that many. Only a dribble in 1942, a bit better but still rather few in 1943 and 44.

Why is the J2M so short and stubby? It looks almost like a souped up I-16 (or an I-180). I thought such a short fuselage had been abandoned as a design feature by the middle of the war. I thought it tended to make aircraft unstable. Am I wrong about that? Is there some advantage to the short length other than weight savings (which I think would be marginal...?) Carrier storage?

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## DarrenW (Mar 19, 2022)

GregP said:


> What does THAT mean? If I do give a red X, all it means is "I disagree." Doesn't mean you're evil or anything. Really.


Greg we discussed all of this over a year and half ago. I accepted your explanation then and was only having a bit of fun during what I felt at the time seemed to be a building of emotion over the comments I made about the Jack.

To recap my opinion of the J2M, it's actual performance wasn't close to what we see in TAIC reports. No surprise there, as this is true of practically ever Japanese aircraft evaluated by the center. This is due to the overall acceptance of the most favorable (i.e. inflated) values concerning properties such as aerodynamic drag, prop efficiency, thrust augmentation, and engine performance used for the CALCULATED performance figures. 

I'd look for a ten percent reduction in performance as a ballpark figure, which would put the maximum speed of a factory fresh aircraft in good condition pretty darn near to what the JNAF achieved during ACTUAL flight testing of the aircraft during the war.

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## GrauGeist (Mar 19, 2022)

Wild_Bill_Kelso said:


> Why is the J2M so short and stubby? It looks almost like a souped up I-16 (or an I-180). I thought such a short fuselage had been abandoned as a design feature by the middle of the war. I thought it tended to make aircraft unstable. Am I wrong about that? Is there some advantage to the short length other than weight savings (which I think would be marginal...?) Carrier storage?


The Raiden was designed to be a fast climbing, high altitude interceptor.

It never saw carrier ops.

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## Wild_Bill_Kelso (Mar 19, 2022)

So why so short


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## Ivan1GFP (Mar 19, 2022)

It was 32 feet 8 inches in length which isn't amazingly short.
It was just very wide because it had a very large diameter Mitsubishi Kasei engine normally considered a "Bomber Engine" buried deep in the fuselage.
The variant of the Seafire in the same photograph is about 2.5 feet shorter.

- Ivan.

https://acesflyinghigh.files.wordpr...en_in_the_philippines_taic_in_flight_1945.jpg

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## Wild_Bill_Kelso (Mar 19, 2022)

Ivan1GFP said:


> It was 32 feet 8 inches in length which isn't amazingly short.
> It was just very wide because it had a very large diameter Mitsubishi Kasei engine normally considered a "Bomber Engine" buried deep in the fuselage.
> The variant of the Seafire in the same photograph is about 2.5 feet shorter.
> 
> ...



Very interesting, I never realized that, always thought it was short and fat... I hadn't considered the position of the engine etc.


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## XBe02Drvr (Mar 19, 2022)

Ivan1GFP said:


> It was 32 feet 8 inches in length which isn't amazingly short.
> It was just very wide because it had a very large diameter Mitsubishi Kasei engine normally considered a "Bomber Engine" buried deep in the fuselage.
> The variant of the Seafire in the same photograph is about 2.5 feet shorter.
> 
> ...


Hmmm....eyeballing that Raiden and Hellcat side by side, it appears the Raiden's engine moment would be less than normal for its size and weight class, making aft structural weight critical for CG reasons. Betcha it was real snappy in the vertical fight. Not much polar moment. I was re-reading _The Right Stuff_ (strolling down memory lane) for giggles last night and was struck by how the silhouette of the Raiden in that pic called to mind the Bell X1.

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## Wild_Bill_Kelso (Mar 19, 2022)

Ivan1GFP said:


> It was 32 feet 8 inches in length which isn't amazingly short.
> It was just very wide because it had a very large diameter Mitsubishi Kasei engine normally considered a "Bomber Engine" buried deep in the fuselage.
> The variant of the Seafire in the same photograph is about 2.5 feet shorter.
> 
> ...



I was looking at this photo, and noticed that if you shorten the Raiden's nose, it looks a lot like a (slightly hump-backed) F6!

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## NevadaK (Mar 21, 2022)

A couple additional photos for your enjoyment. Also a similar group shot with a Hayate

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## GregP (Mar 21, 2022)

The radial is in front of the wing leading edge and the driveshaft is something like 3 feet long or so. the cockpit is enormous when compared with other fighters of similar size. it is a big cockpit even next to a P-47!

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## AerialTorpedoDude69 (Sep 30, 2022)

Just a quick note here:
The Ki-44 II didn't receive the continuous development that the other airframes received, probably because the airframe itself wasn't that great.
For example, thrust stacks were never added, except as a field modification (and they contributed around 8-10 MPH, making it almost as fast as a Frank. More crucially, it never got water methanol injection. And its airfoil, which was an NN-2 (similar to the Ki-43), was fairly draggy. Overall, the airframe had been maxed out so the designers didn't invest any more development effort into it. And as an interceptor, its high altitude performance sucked, particularly in comparison to aircraft that had direct injection engines, such as the Ki-61 II and the J2M.

The Jack, in comparison, had a lot more stream-lining, a laminar-flow wing, a direct injection engine that performed better than most of the carbureted engines (all of the Japanese engines lacked a sufficient supercharger) at high altitude.

The main issue here is that the Japanese high command didn't invest enough resources in developing a highly reliable interceptor. They instead focused on high output engines that weren't reliable. The main thing to take away is that they missed an opportunity to develop an ultra lightweight interceptor around a 1,500 HP engine with a "laminar flow" wing, thrust stacks, direct injection, alu 7075, and water methanol injection. Had they done so, they might have had a 400+ MPH aircraft that ran reliably on poor quality fuel and was capable of intercepting the B-29 at high altitude.

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## Clayton Magnet (Sep 30, 2022)

The J2M was a formidable fighter, assuming it was running to spec. And as per this article ( which was posted years prior) was superior to a F6F-5

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## Kilkenny (Sep 30, 2022)

AerialTorpedoDude69 said:


> Just a quick note here:
> The Ki-44 II didn't receive the continuous development that the other airframes received, probably because the airframe itself wasn't that great.
> For example, thrust stacks were never added, except as a field modification (and they contributed around 8-10 MPH, making it almost as fast as a Frank. More crucially, it never got water methanol injection. And its airfoil, which was an NN-2 (similar to the Ki-43), was fairly draggy. Overall, the airframe had been maxed out so the designers didn't invest any more development effort into it. And as an interceptor, its high altitude performance sucked, particularly in comparison to aircraft that had direct injection engines, such as the Ki-61 II and the J2M.
> 
> ...


Wow. Never read this before. Enlightening. But it seems that most aviation writers agree that the Ki-44 didn't get much attention from the IJA. If it had, it would likely have been operational much earlier and perhaps gotten some of the upgrades you mentioned above.

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## AerialTorpedoDude69 (Sep 30, 2022)

Kilkenny said:


> Wow. Never read this before. Enlightening. But it seems that most aviation writers agree that the Ki-44 didn't get much attention from the IJA. If it had, it would likely have been operational much earlier and perhaps gotten some of the upgrades you mentioned above.


There's an early-war USAAF air combat training manual which used aircraft models to demonstrate tactics against various Japanese aircraft. The manual's instrution for engaging aircraft such as the Zero and Oscar were pretty straightforward: dive, dive, dive. Dive to attack, dive to escape.

The instructions for engaging a Tojo were tortured, complicated, and difficult. At the time, the Tojo was faster and more manueverable at many altitudes than the US planes it was facing off against (except maybe a P-38E but I'm not sure), and the Tojo could dive and roll to some extent with those aircraft. The only real way to shake one was with complex tricks that exploited some of the handling issues of the Tojo, such as its "inability" to perform certain maneuvers, such as snap rolls.

Going off the tactics the US developed, you could tell that fighting a Tojo was far more difficult than fighting against a Zero or Oscar.

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## Greg Boeser (Oct 1, 2022)

When the 23rd FG began encountering them in China in mid-'43, the Tojo really freaked them out. After slapping Ki-27s and Ki-43s around for a year, they found themselves at a distinct disadvantage. When some of his pilots doubted their ability to handle tgem in the air, Chennault is reported to have said, "Well, we'll just have to beat them on the ground, then."

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## Kilkenny (Oct 1, 2022)

AerialTorpedoDude69 said:


> There's an early-war USAAF air combat training manual which used aircraft models to demonstrate tactics against various Japanese aircraft. The manual's instrution for engaging aircraft such as the Zero and Oscar were pretty straightforward: dive, dive, dive. Dive to attack, dive to escape.
> 
> The instructions for engaging a Tojo were tortured, complicated, and difficult. At the time, the Tojo was faster and more manueverable at many altitudes than the US planes it was facing off against (except maybe a P-38E but I'm not sure), and the Tojo could dive and roll to some extent with those aircraft. The only real way to shake one was with complex tricks that exploited some of the handling issues of the Tojo, such as its "inability" to perform certain maneuvers, such as snap rolls.
> 
> Going off the tactics the US developed, you could tell that fighting a Tojo was far more difficult than fighting against a Zero or Oscar.


That's what I've read... Instead of wasting time with the Ki-61's engine, the IJA would have been much better off putting the equivalent effort in making the Ki-44 even better (or putting a Kinsei in the Ki-61 from the outset)... That way it would have remained a decent interceptor until the Shinden came along to replace it. (Though still not enough to stop the American juggernaut.)

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## AerialTorpedoDude69 (Oct 1, 2022)

Kilkenny said:


> That's what I've read... Instead of wasting time with the Ki-61's engine, the IJA would have been much better off putting the equivalent effort in making the Ki-44 even better (or putting a Kinsei in the Ki-61 from the outset)... That way it would have remained a decent interceptor until the Shinden came along to replace it. (Though still not enough to stop the American juggernaut.)


It's an interesting dilemma that the Japanese strategic planners faced: the war in the Pacific required aircraft with incredible ranges and their carrier fleet didn't have a lot of elevators that could support larger aircraft. 

They had to choose between fewer fighters available for strike missions and putting their carriers into harm's way more often or larger strike forces and putting their carriers at the edge of the effective range of their opponents strike forces. As you might expect, the IJN favored offense over defense. What I don't understand is why the IJA didn't do as you've suggested. Because the Ki-43 was, in my opinion, one of the worst aircraft of the war, despite a good combat record. While the army did fly long range missions in New Guinea, that was not the case in Indo China. It's befuddling why they didn't design the Ki-43 around the Kinsei. Had they done so, they wouldn't have needed the Ki-44.

AFAIK, the only early war Army aircraft that used the Kinsei were several transport aircraft. In comparison, USAAF early war aircraft includes the P-38E and P-47C, both excellent (and extremely heavy) aircraft. Throwing Sakae-equipped aircraft at these two beasts seems a little insufficient.


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## Kilkenny (Oct 1, 2022)

AerialTorpedoDude69 said:


> It's an interesting dilemma that the Japanese strategic planners faced: the war in the Pacific required aircraft with incredible ranges and their carrier fleet didn't have a lot of elevators that could support larger aircraft. So they had to choose between fewer fighters available for strike missions and putting their carriers into harms way more often or larger strike forces and putting their carriers at the edge of the effective range of their opponents. As you might expect, the IJA favored offense over defense. What I don't understand is why the IJA didn't do as you've suggested. Because the Ki-43 was, in my opinion, one of the worst aircraft of the war, despite a good combat record. While the army did fly long range missions in New Guinea, that was not the case in Indo China. It's befuddling why they didn't design the Ki-43 around the Kinsei. Had they done so, they wouldn't have needed the Ki-44.
> 
> AFAIK, the only early war Army aircraft that used the Kinsei were several transport aircraft. In comparison, USAAF early war aircraft includes the P-38E and P-47C, both excellent (and extremely heavy) aircraft. Throwing Sakae-equipped aircraft at these two beasts seems a little insufficient.


Agree. The Kinsei had much more growth potential than the Sakae. But a Ki-43 powered by a Kinsei would still have needed a stronger structure, sealing fuel tanks, and more pilot armor--- so there might have been no improvement in level speed (but perhaps diving). Imagine the two and a half years the Japanese could have owned the skies if they had that new Ki-43 plane and an early A6M8 at the outset. The Ki-61, Ki-44 and perhaps the Raiden would not be needed. The final challenge would either be a reliable Hayate or the Ki-84 powered by an A18 or A20 engine. If that happened, then a Shinden interceptor would have been superfluous.

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## Admiral Beez (Oct 1, 2022)

Conslaw said:


> The navy's (post-zero) general purpose fighters, the A7M and the N1K1, were either not ready for production at all (A7M) or defied mass production (N1K - peak production 106 units/month in Sept. 1944).


Is the IJN the only carrier force to specify a frontline fighter incapable of flying from its carriers? Why not make the Jack carrier capable or divert its resources to a carrier fighter? Since when is it the navy’s job to intercept B-29s? That nation was messed up.


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## GrauGeist (Oct 1, 2022)

The KI-60 was an answer to the Army's request in late 1939 for a well armed interceptor built around the DB601.
The KI-61 was to be a lighter, multi-purpose version of the KI-60.

At the time of the KI-61's introduction in the early 40's, it was the only Japanese fighter that had a service ceiling of 38,000 feet, well above that of the KI-43 and A6M.

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## NevadaK (Oct 2, 2022)

Kilkenny said:


> Agree. The Kinsei had much more growth potential than the Sakae. But a Ki-43 powered by a Kinsei would still have needed a stronger structure, sealing fuel tanks, and more pilot armor--- so there might have been no improvement in level speed (but perhaps diving). Imagine the two and a half years the Japanese could have owned the skies if they had that new Ki-43 plane and an early A6M8 at the outset. The Ki-61, Ki-44 and perhaps the Raiden would not be needed. The final challenge would either be a reliable Hayate or the Ki-84 powered by an A18 or A20 engine. If that happened, then a Shinden interceptor would have been superfluous.


Along these lines? 






Nakajima Ki-116 - Wikipedia







en.wikipedia.org





One of those promising developments that never progressed very far. A couple images speculating its appearance as only one prototype was constructed.

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## XBe02Drvr (Oct 2, 2022)

AerialTorpedoDude69 said:


> It's an interesting dilemma that the Japanese strategic planners faced: the war in the Pacific required aircraft with incredible ranges and their carrier fleet didn't have a lot of elevators that could support larger aircraft. So they had to choose between fewer fighters available for strike missions and putting their carriers into harms way more often or larger strike forces and putting their carriers at the edge of the effective range of their opponents.


You seem to think the Japanese had anything like coordinated strategic planning. They had an Army agenda and a Navy agenda, and never the twain shall meet. (Except at the Hirohito level, and he was reluctant to dirty his immaculate imperial robes in that muddy fighting ring.)


Admiral Beez said:


> Is the IJN the only carrier force to specify a frontline fighter in sole of flying from its carriers? Why not make the Jack carrier capable or divert its resources to a carrier fighter? Since when is it the navy’s job to intercept B-29s? That nation was messed up.


Making a land based fighter carrier capable (especially a small elevator carrier) is a difficult proposition and rarely 100% successful.
When it comes to B29 defense, *Rule .303* applies: _"If you have the resources at hand to cope with a looming existential disaster, it is your responsibility to provide whatever aid is in your power."_

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## Kilkenny (Oct 2, 2022)

NevadaK said:


> Along these lines?
> 
> 
> 
> ...


This was a really nice looking plane and a decent concept (as us NASA people would say, "If it looks good, it probably flies good"), but too much like the Ki-100 and not fast enough... When the Homare engine was performing as specified, the Hayate was truly formidable... But this plane would have experienced difficulties with a Mustang or Corsair piloted by someone experienced in BNZ not interested in dogfighting...

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## Shortround6 (Oct 2, 2022)

I see problems with the timing of some of these engines.

The Kinsei 61/2 engine was a very good engine, trouble is when does it show up? If the Kinsei 61 doesn't show up until 1944 it doesn't do the Japanese much good. 

The Kinsei 54 was good for 1300hp for take-off, 1200hp at 3,000 meters and 1100hp at 6,200 meters. This showed up in 1942 (?) 

The engine in the Ki-43 II was good for 1150hp for take-off, 1150hp at 2450 meters, and 980hp at 5600 meters. 

The engine in the Ki-61 was good for about 1175-1180hp for take off and 1080-1100 hp at 3500-3900 meters. This is actually with a few percent of the Allison engines used in the P-40s/P-39s except the Japanese can't use WER. 

At the time they working on the Ki-61 (1940-1941) the Kinsei engine may have been the 40 series engines, these had single speed superchargers and around 1080hp at 2000 meters for many versions. 

The Ki-44 II with the Ha-109 engine shows up in the very late fall of 1942. This engine has the power to get the job done in late 1942 and into 1943. (Showed up in the Ki-49 bomber before the Ki 44 fighter). 

The Japanese put two speed superchargers on many of their engines (along with other improvements) in 1940-41-42, later on there seems to have been a number jump in power so be very careful when trying to figure out what the Japanese could have done in 1941-43 as, just like the allies, many of the 1944 engines did not exist in 1941-1943.

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## AerialTorpedoDude69 (Oct 2, 2022)

XBe02Drvr said:


> You seem to think the Japanese had anything like coordinated strategic planning. They had an Army agenda and a Navy agenda, and never the twain shall meet. (Except at the Hirohito level, and he was reluctant to dirty his immaculate imperial robes in that muddy fighting ring.)
> 
> Making a land based fighter carrier capable (especially a small elevator carrier) is a difficult proposition and rarely 100% successful.
> When it comes to B29 defense, *Rule .303* applies: _"If you have the resources at hand to cope with a looming existential disaster, it is your responsibility to provide whatever aid is in your power."_


In "Secret Weapons and World War II: Japan in the Shadow of Big Science" the author mentioned that Japan was on the verge of developing the neccessary bureaucracy for sharing military technology between different service branches, but the chief organizer died in 1940, just prior to implementing the system. He had only managed to establish a basic framework which both services did not invest many resources in.

You may have misunderstood my poorly written comment though. I was not saying they needed an inter-service aircraft, but rather critiqued the IJA's decision to use the Sakae on a land-based fighter. They should have used the Kinsei. While the Ki-116 would have been great, stapling the Kinsei on any random aircraft isn't preferable over a purpose-built aircraft.



Shortround6 said:


> I see problems with the timing of some of these engines.
> 
> The Kinsei 61/2 engine was a very good engine, trouble is when does it show up? If the Kinsei 61 doesn't show up until 1944 it doesn't do the Japanese much good.
> 
> ...


The fuel-injected derivative of the Kinsei became available in late 1941 (According to Goodwin, though, it was available in 1940). It reached aircraft in late 1942, such as the Ki-46 III. Jiro Horikoshi mentioned in his book that a 1,500 HP Zero could have made its way into combat by the Summer of 1943, enough to slow the progression of the war. I think the big problem wasn't the engine though. The issue was that the airframe was obsolete. That big draggy wing that the Japanese used on their fighter aircraft, which improved slow-speed lift at the expense of top maximum speed and sustained turn rate, would never be able to perform at high speed. It didn't matter what kind of engine was used. The faster a Zero went, the poorer its turn performance would become.


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## tomo pauk (Oct 2, 2022)

AerialTorpedoDude69 said:


> The fuel-injected derivative of the Kinsei became available in late 1941. It reached aircraft in late 1942, such as the Ki-46 III. Jiro Horikoshi mentioned in his book that a 1,500 HP Zero could have made its way into combat by the Summer of 1943, enough to slow the progression of the war.



There was a lot more than fuel injection that made the Kinsei 60 series capable for 1500 HP (and a bit more). Like the water-alcohol injection (curiously enough, not fitted on the Ki-100 in 1945?), and the bigger supercharger - 12.6 in impeller vs. the 11.4 in on the 50 series.
Granted, the fully-rated Kinsei 62 on a Zero from early 1943 on would've made the life ... interesting to the Allied pilots & crewmen.

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## AerialTorpedoDude69 (Oct 2, 2022)

tomo pauk said:


> There was a lot more than fuel injection that made the Kinsei 60 series capable for 1500 HP (and a bit more). Like the water-alcohol injection (curiously enough, not fitted on the Ki-100 in 1945?), and the bigger supercharger - 12.6 in impeller vs. the 11.4 in on the 50 series.
> Granted, the fully-rated Kinsei 62 on a Zero from early 1943 on would've made the life ... interesting to the Allied pilots & crewmen.


I think according to Goodwin (?), the 50-series Kinsei (which had bowl-prime indirect injection) had MW injection. The 60 series did not AFAIK. There may have been an issue integrating direct injection with MW injection. (EDIT: The 62-Ru supposedly added MW injection and fuel injection at the same time, the 61 may have had them as well.) I remember reading about how the Kasei produced too much white smoke in the Raiden with a Kasei 23. Since the direct injection system is mixing fuel-air inside of the cylinder along with the MW mixture being sprayed into the throttle body, it would partially explain the presence of white smoke (an incorrect MW installation). It must have been easier to integrate in a carburated system. But my knowledge of this subject is old and potentially incorrect.

IMO, the issue with the Zero was its big wing. The low-speed turn rate would be great for pilots in disadvantageous position (I.E. being attacked from on high) but a liability when diving to attack or when diving to escape. This characteristic was a flaw on most Japanese aircraft, including the Raiden, Hayate, Shiden, and others. Only a few, like the Ki-44, seemed to have good controllability at high speed relative to their opponents.


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## GrauGeist (Oct 2, 2022)

The J2M (Raiden) was noted for it's ability to dive and it's wing was slightly smaller than the F6F's while both types had a comparable fuselage length.

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## AerialTorpedoDude69 (Oct 2, 2022)

GrauGeist said:


> The J2M (Raiden) was noted for it's ability to dive and it's wing was slightly smaller than the F6F's while both types had a comparable fuselage length.


As far as I know, that's totally true. The Raiden was also exceptionally lightweight, which meant its dive performance wasn't as good as most American aircraft, since weight is a key characteristic of planes that can dive well. IIRC, according to the TAIC report, its airlerons got heavy at high speed in the 325 MPH range. So it could dive but it wasn't going to turn when diving at high speed.

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## Kilkenny (Oct 2, 2022)

Shortround6 said:


> I see problems with the timing of some of these engines.
> 
> The Kinsei 61/2 engine was a very good engine, trouble is when does it show up? If the Kinsei 61 doesn't show up until 1944 it doesn't do the Japanese much good.
> 
> ...


That's why I have soft spot for the Ki-44... It was a good when first deployed just before WW2, and great by 1942. But the IJA just didn't promote it much or spend much effort improving it (as opposed to the slow and flimsy Ki-43)... So ATD69, I agree with you!

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## Admiral Beez (Oct 2, 2022)

XBe02Drvr said:


> Making a land based fighter carrier capable (especially a small elevator carrier) is a difficult proposition and rarely 100% successful.


I understand. My thinking was for the IJN not to make the J2M and instead using the IJN's limited resources to make something entirely different for its carriers. The IJN needs to match the Hellcat and Corsair, not the B-29.... unless ten of them are flying fast and low towards your CBG!

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## XBe02Drvr (Oct 2, 2022)

AerialTorpedoDude69 said:


> That big draggy wing that the Japanese used on their fighter aircraft, which improved slow-speed lift at the expense of top maximum speed and sustained turn rate, would never be able to perform at high speed. It didn't matter what kind of engine was used. The faster a Zero went, the poorer its turn performance would become.


Obsessions die hard. IJN and IJA were rather slow to move on from agility and maneuverability to speed and firepower, and naturally, as the customers, they called the shots. Reynolds and Mach LLC* just wouldn't let them have their cake and eat it too.
*Specializing in the Law of Physics

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## tomo pauk (Oct 3, 2022)

AerialTorpedoDude69 said:


> I think according to Goodwin (?), the 50-series Kinsei (which had bowl-prime indirect injection) had MW injection. The 60 series did not AFAIK. There may have been an issue integrating direct injection with MW injection. I remember reading about how the Kasei produced too much white smoke in the Raiden with a Kasei 23. Since the direct injection system is mixing fuel-air inside of the cylinder along with the MW mixture being sprayed into the throttle body, it would partially explain the presence of white smoke (an incorrect MW installation). It must have been easier to integrate in a carburated system. But my knowledge of this subject is old and potentially incorrect.



Ki-46-III is, at least by my knowledge, the only aircraft powered by a Kinsei that featured a water-alcohol injection system. Engine in question was the Model 61. TAIC manual notes the same.



AerialTorpedoDude69 said:


> IMO, the issue with the Zero was its big wing. The low-speed turn rate would be great for pilots in disadvantageous position (I.E. being attacked from on high) but a liability when diving to attack or when diving to escape. This characteristic was a flaw on most Japanese aircraft, including the Raiden, Hayate, Shiden, and others. Only a few, like the Ki-44, seemed to have good controllability at high speed relative to their opponents.



Wing on the Zero was of about same area, thickness and profile as on the P-36 or P-40. Late P-40 prototype (in 1944) with a proper engine was making 420+ mph in level flight, and P-40s family was reasonably fast in dive.
Even the F4F was with a bigger wing than what Japanese fighters had.

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## GrauGeist (Oct 3, 2022)

It's not the size of the wing, but the size of the aerlerons and how the leverage of the control are configured.

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## GregP (Oct 3, 2022)

tomo pauk said:


> Ki-46-III is, at least by my knowledge, the only aircraft powered by a Kinsei that featured a water-alcohol injection system. Engine in question was the Model 61. TAIC manual notes the same.
> 
> 
> 
> ...



The F4F-4 needed a bigger wing since it came in at 7,950 lbs in the F4F-4 model and 8,271 lbs in the FM-2 model. The F4F-4 came in at 30.6 lbs/ sq ft and the FM-2 came in at 31.8 lbs/ sq ft, both at normal gross weight.

The A6M-5 came in at 6,025 lbs and had a wing loading of 26.3 lbs/ sq ft at that weight.

So, the A6M-5 had 14 - 15% lighter wing loading than the F4F-4 and about 17% lighter wing loading than the FM-2. It also had a bout 20% better power loading than the F4F and about 15% better power loading than the FM-2, all of which should account for the superiority of the A6M-5 over the primary naval early adversary.

There weren't any P-40s that went 420 mph except for the three P-40Qs that were not selected for production and never saw combat. The A6M-5 handily outperformed the P-36, P-40, F4F-3/4, and FM-2. The A6M didn't really meet its match until the F6F came into service, at which point it really needed an engine and slight aerodynamic update or a replacement fighter, neither of which ever saw wartime service except in prototype, non-combat form.

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## XBe02Drvr (Oct 3, 2022)

Leave it to Greg to point out there are multiple factors that combine to make a fighter's performance superior/successful, not just a single superior quality such as horsepower, wing area, aileron effectiveness, or weight. Every aircraft is a bundle of compromises to be considered in their totality, complicated as that may be, and not given to one-liner simple answers.
I used to fly a commuter airliner that was optimized for serving small town airports and being operated and maintained by less experienced personnel. Its powerful engines, high lift wings, high gear and flap speeds, and excellent prop beta and brakes gave it great airport performance, but those same features, plus its boxy fuselage and profusion of stabilizing fins and vortex generators gave it a Vne of 247 knots and an economical cruise of <200. We never broke one in a TO/Ldg accident or incident. Our competition flew "Lawn Darts" (Metroliners) which were go-fast machines, sacrificing everything for speed, such as handling, takeoff & landing performance, even passenger seating comfort and luggage capacity. Because of their >250 knot Vne, they always got high altitude ATC handling into the big places, while we got sequenced with the Pipers, Cessnas, and Twin Otters. They would check in 2K altitude above us and ten miles behind and beat us to the gate by 5 or 10 minutes. They also managed to leave wreckage on many of the back country airports in northern New England.

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## GregP (Oct 3, 2022)

Sometimes the absolute best-performing aircraft is NOT the best choice for the task.

A Mosquito is a very high-performance aircraft for its configuration and mission, but has a Vmc of 165 mph! If anything happens before you get to 165 mph, you are going straight in or crashing. That was acceptable for a wartime bombing airplane designed to penetrate enemy defenses with speed, but would NEVER be accepted for peacetime executive air travel.

A B-25 wasn't as fast, but was quite safe in civilian hands. Lots of them still flying reliably.

If I were hauling rectangular boxes of freight ( be honest, that is MOST freight) over short/medium distance, a Short Skyvan or Cessna Caravan might be a great choices. But they can hardly be considered stylish ramp presences.

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## Clayton Magnet (Oct 3, 2022)

Kilkenny said:


> That's why I have soft spot for the Ki-44... It was a good when first deployed just before WW2, and great by 1942.


Ki-44 wasn't fielded until well after the war started

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## GrauGeist (Oct 3, 2022)

The KI-44 prototype was first flown in 1940 and two prototypes and seven pre-production models were sent to Indochina for evaluation and were operational in December of 1941.

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## EwenS (Oct 3, 2022)

Clayton Magnet said:


> Ki-44 wasn't fielded until well after the war started


On 15 Sept 1941 the second and third Ki-44 prototypes and 7 pre-production with the latest modifications were assigned to an experimental squadron that became the 47th Independent Chutai. By 7 Dec 1941 this unit was based in Indochina. 3 force landed on 24 Dec 1941 while in transit to Don Muang, Thailand. By mid Jan 1942 they were operational in the skies over Singapore and had moved to Kuantan in Malaya.

Bloody Shambles Vol 1.

Production Ki-44-1a began to come off the production line in Jan 1942.

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## AerialTorpedoDude69 (Oct 3, 2022)

tomo pauk said:


> Ki-46-III is, at least by my knowledge, the only aircraft powered by a Kinsei that featured a water-alcohol injection system. Engine in question was the Model 61. TAIC manual notes the same.
> 
> 
> 
> ...


Thanks, my memory is failing me. 

 Shinpachi
posted a document which showed that water-methanol injection didn't show up until the Kinsei 62-Ru, which also received an exhaust driven turbosupercharger. According to that document, there was no Kinsei Ha-32-62. There was only a 62-Ru (turbo). Which means every version of the Kinsei up until the 62-Ru had a carburetor and lacked WM injection. That also means it was the Ki-46 IV that had water methanol injection and that the Ki-46-III lacked it. The Ki-46-III apparently had a Kinsei 61 engine.

Shinpachi's translation suggests that the Ki-46 III had WM injection though. It may be that the table in that document misplaced the Kanji and that both the 61 and 62-Ru have MW-injection. Given (in your excellent post) the Soviet testing of the Ki-46 (assumedly a III as the IV was a prototype) revealed MW-injection in the Kinsei, I think we have to assume it did indeed have MW injection.

EDIT: The Zero definitely had good low-speed handling characteristics, which is a sign of a high lift wing. Larger control surfaces and big wings (relative to the aircraft) do not perform well at high speeds. It's why there are no fast planes that have great low-speed handling characteristics. Laminar wings stall out earlier than non-laminar wings.

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## GregP (Oct 3, 2022)

Tomo's posts are usually excellent.

He is definitely one of the forum assets.

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## Just Schmidt (Oct 3, 2022)

Just a hunch, but I suspect Clayton Magnet is referring to the second world war instead of the pacific war.

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## Clayton Magnet (Oct 3, 2022)

Just Schmidt said:


> Just a hunch, but I suspect Clayton Magnet is referring to the second world war instead of the pacific war.


That would be correct. 
The post that I replied to implied that WW2, not specifically the pacific portion, started in late 1941

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## GregP (Oct 4, 2022)

OK, finally. Jack versus Tojo, or J2M versus Ki-44. First, I'm using the TAIC Report # 2 dated 1945 for the comparison. Never mind when they first flew, I'm talking about the J2M3 versus the Ki-44 II. They first started flying the Ki-44 family operationally in some numbers in Jan 42 and the J2M family was first seen in some numbers in Dec 42. So, the Ki-44 had about 10 months on the J2M operationally. They built some 1,225 Ki-44s and some 621 J2Ms, so there were about twice as many Ki-44s as J2Ms.

Weights: Ki-44 was 4300 lbs empty, 6100 lbs normal load, 6610 lbs overload. The J2M was 6259 lbs empty, 7079 lbs normal load and 8130 overload. So, the J2M was slightly heavier empty than a Ki-44 at normal fighter take off.

Power Loading: Look at takeoff, best mil power, and best WER power. Ki-44 II: PL takeoff: 4.07 lbs/ hp. Best mil power: 4.69 lbs/ hp at 17,200 feet. Best WER: 3.89 lbs/hp at 5,000 feet. J2M3: takeoff: 3.91 lbs/ hp. Best mil power: 4.69 lbs/ hp at 18,100 feet. Best WER: 4.10 lbs/hp at 16,600 feet. So, there is very little to choose as far as power loading goes and, at best military power, they are even up. J2M has about 2,500 feet better service ceiling (38,800 feet versus 36,350 feet). But, after finding out they couldn't hit anything at 30+ thousand feet, the B-29s were coming in at around 20,000 feet anyway, so the advantage is not really all that useful.

Wing loading at normal weight: Ki-44 II: 36.09 lbs/ square foot. J2M3: 33.89 lbs/ square foot. Very little to choose between them, but the J2M comes in maybe 6% better. Doesn't translate into much in the real world.

Speed: J2M3 is 32 mph faster at best height and 24 mph faster at sea level. At sea level, both are around as fast as the US opposition. Around 20,000 feet, the Ki-44 is maybe about even with US opposition or slightly slower, but the J2M3 is 30+ mph faster. That 32 mph would make a BIG difference if chasing a B-29, but little difference practically if engaging with fighters because the faster fighter opposition is faster than both Japanese aircraft and the slower opposition is about even with the Ki-44 II, making it not so much of a factor unless chasing B-29s.

Climb: Both are 1,000+ feet per minute better than any US counterpart.

Armament: US opposition has 4/50-cal or 6/50-cal. Technically the Ki-44 II has 6/50-cal and 2/40mm cannons … but the cannons have only 10 shots and the shells are slow, so they are not much use. The J2M3 has 4/20 mm cannons for an obvious armament advantage, especially against bombers.

From the above, I say the Ki-44 was an EXCELLENT choice, especially for 10 months when there were no J2Ms around. There were twice as many available and the Ki-44 likely was more reliable, given reports of J2M malfunctions. Range without extra fuel tanks was about a wash, with the Ki-44 II having slightly more combat range at 1,500 feet (740 miles versus 670 miles). Admittedly there wasn't a lot of fighting at 1,500 feet, but it is the comparison we have.


I'd say twice as many Ki-44 IIs would tip the balance in favor of the Ki-44, but nobody would be unhappy with a J2M3 as long as it was running correctly. From what I hear, that was a gamble for many J2M pilots. I'd take the old reliable Ki-44 II if offered the choice, based on the numbers. But, the Ki-44 was more lightly built, and that MIGHT affect the choice. Still, a reliable airplane is likely a better choice than an unreliable airplane.

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## Clayton Magnet (Oct 4, 2022)

GregP said:


> Technically the Ki-44 II has 6/50-cal and 2/40mm cannons


I was under the impression that the Shoki would have at most four machine guns. Two synchronized Ho-103 in the fuselage, and one in each wing. Was there actually provision for six to be installed?

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## GrauGeist (Oct 4, 2022)

Clayton Magnet said:


> I was under the impression that the Shoki would have at most four machine guns. Two synchronized Ho-103 in the fuselage, and one in each wing. Was there actually provision for six to be installed?


From what I've read, the KI-44 in it's various configurations never had more than two weapons in the cowl and one in each wing.
The cowl positions were either 7.7mm or 12.7mm MGs and the wing positions were either 12.7mm MGs or 40mm cannon.

There were proposals to upgun to cannon in all positions, but these remained on paper.

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## Reluctant Poster (Oct 4, 2022)

Admiral Beez said:


> Is the IJN the only carrier force to specify a frontline fighter incapable of flying from its carriers? Why not make the Jack carrier capable or divert its resources to a carrier fighter? Since when is it the navy’s job to intercept B-29s? That nation was messed up.


The US wasn't exactly immune to interservice rivalry, the Japanese were just a little more extreme.

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## cherry blossom (Oct 4, 2022)

I have been struggling with the information in this thread that most versions of the Kinsei 60 series did not use methanol water injection at military power and above. 

Firstly, according to Goodwin and Starkings, water injection was introduced from the Kinsei 52 and 53 (MK8B and MK8C). There is no obvious need to change the system for adding water to air - fuel mixture on changing to the direct injection of fuel, so the water may have been added before the supercharger (hopefully the methanol should not require backfire screens). 

Secondly, if we use that famously accurate source, Wikipedia, to find the power of the P&W R-2000 Pratt & Whitney R-2000 Twin Wasp - Wikipedia we find "The R-2000 produced 1,300 hp @ 2,700 rpm with 87 octane, 1,350 hp with 100 octane and 1,450 hp @ 2,800 rpm with 100/130-grade fuel." With almost the same swept volume, the Ha-112 II gave 1,500 ps @ 2,600 rpm with 92 octane. Unfortunately, the boost is given as unknown by G & S on page 119 but it seems to me that it would need to be high enough to require either 100/130 octane fuel or water injection even if the use of direct injection allowed better scavenging via keeping the exhaust valve open longer. 

There is a Ki-100 at Cosford (see thread Kawasaki Ki 100 shots). Can someone go over and count the ports for adding liquids? Is Joe Picarella in the house?

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## Vincenzo (Oct 4, 2022)

For the information in the engines section, Shinpachi works, Kinsei 61 had not water injection but the Kinsei 61-ru or 62-ru (it's possible a mistyping) had it

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## GregP (Oct 4, 2022)

Clayton Magnet said:


> I was under the impression that the Shoki would have at most four machine guns. Two synchronized Ho-103 in the fuselage, and one in each wing. Was there actually provision for six to be installed?



According to several sources, yes. I can't say for sure, never having seen a Ki-44 of any variant. The armament claim comes for the TAIC manual No. 2, dated 1945, so they probably knew a thing or two about the Ki-44 II by then.


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## Shortround6 (Oct 4, 2022)

Well for some of these engines a lot depends on the altitude. and some depends on time.
The US engines were rated at 5 minutes of time _subject to engine staying within temperature limits. _
I don't know about the Japanese engines, if they had a 1 minute or 3 minute rating or 5 minute.

I would also note that not all superchargers were created equal. P&W tended to use a pretty small supercharger (in capacity ) so it would use the least amount of power at take-off.

A R-2000 was good for 1450hp using 49.5in MAP (1258mm) +9.8lb
However it was only good for take-off and up to 1000ft.
In high gear it was good for 1100hp at 16,000ft.

Some engines that were rated at 1350hp (and many of them were rated using 100/130 fuel) would give you the 1350hp at 3000ft in low gear but only 1100hp in high gear at 16,000ft.
Some engines were given different ratings depending on what kind of main bearings they used.

Some of the engines rated on 100 octane fuel were rated at 1350hp at take-off/2000ft. In high gear they were rated at 1100hp at 13,200ft. ( a different gear ratio for high gear)

These are all at 2700rpm. 

P & W doesn't seem to have rated the engine for 87 octane. They have one listing using 90 octane but the engine was never was never manufactured. (a lot of these not manufactured engines got model numbers) The Military may very well have rated the engine/s for 87 octane fuel in the manuals for when the planes could not get 100 or 100/130.
A 1945 manual has a quick chart for using 91 octane fuel. The engine is restricted to 1200hp for take-off using 43.5in of map

A British manual (?) might show 87 octane. 91 octane was a US fuel only. At least during the war

The Ha-112-II while rated for 1500hp/2600rpm for take-off was only rated at 1350hp/2500rpm at 6,500ft and 1250hp/2500rpm at 19,500ft. Both which handily beat a R-2000 running at 2550rpm (Normal or max continuous )

The other thing to consider is that the P & W engines were rather conservatively rated. the older R-1830 was rated at close to 1000 hours for transport use. Japanese engines may have been pushed harder (higher temps or something else?)

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## GrauGeist (Oct 4, 2022)

Here's a photo of a captured KI-44-II in the Philippines, 1945 - one weapon in each wing.

I suspect poorly worded descriptions can mislead, for example, many sites state: "it had two machine guns in the cowl and two in the wings", giving the impression of "two in each wing".
The armament would be better described with: "it had two machine guns in the cowl and *one in each wing*".

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## GregP (Oct 4, 2022)

I checked the TAIC manual and the actual description reads, "2/12.7/250 + 2/40/10 or 4/12.7/250." I HAVE seen a source that claims 6 guns, but that was some time back and I can't recall the source exactly. So ... no exact recall for the source generally equals no second source in this forum.

I stand corrected.

I would think that 10 rounds of 40 mm would only be for a bomber interceptor and I would remove the 40s and replace with 20s and more ample ammo supply if I were in command.

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## GrauGeist (Oct 4, 2022)

GregP said:


> I would think that 10 round of 40 mm would only be for a bomber interceptor and I would remove the 40s and replace with 20s and more ample ammo supply if I were in command.


You're not far off the mark, Greg - as I recall, the 40mm gave them a great deal of trouble, so they replaced them with the 12.7mm MG.

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## Greg Boeser (Oct 4, 2022)

Some simply removed the cannon, leaving just the nose guns.

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## Shortround6 (Oct 4, 2022)

here is a drawing from Wiki on the 40mm projectile




There was no cartridge case, the propellent was in the base of the projectile. 

Basically what the Japanese had was gun/rocket launcher that with 1/2 the velocity of the German MK 108, fired a bit slower, and a shell that had about 2/3rds of the explosive. 
And the magazine held 10 rounds. weapon could empty the magazine in in about 1.25 seconds.

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## BiffF15 (Oct 4, 2022)

I just went back through the majority of this thread and have a couple of questions for the knowledgable.

Early on there are comparisons made between the P47N and the J2M3. The speeds and climb rates that I saw were for a max loaded P47 and not one at about half gas over Japan. Does anyone have the charts for a no longer tanked but still with pylons at approx half fuel weight for a P47N? This conversation for a bit was just like the Mustang vs 109 chart comparison seen in other threads. 

I only bring this up as a plane with 33% it's weight being fuel will have a big gain in climb rates once it's down to half fuel vice a plane that only has 150 gallons (10% of it's weight) at takeoff. When a Thunderbolt met a Jack over Japan, its weight would be much lower, and it's climb rate I would think much higher. Numbers are for example only.

Cheers,
Biff

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## GregP (Oct 5, 2022)

BiffF15 said:


> I just went back through the majority of this thread and have a couple of questions for the knowledgable.
> 
> Early on there are comparisons made between the P47N and the J2M3. The speeds and climb rates that I saw were for a max loaded P47 and not one at about half gas over Japan. Does anyone have the charts for a no longer tanked but still with pylons at approx half fuel weight for a P47N? This conversation for a bit was just like the Mustang vs 109 chart comparison seen in other threads.
> 
> ...



That's a problem with a LOT of WWII comparisons. The U.S.A. has a lot of data about their planes while some of the basic data about Axis aircraft are seemingly lifted from one website to the next, verbatim. And the lack of things like standard climb from SL to 10,000 and 20,000 feet or a standard metric number of meters makes comparisons difficult and/or almost impossible. If we DO get decent data in some area, then we seemingly fight over fuel quality, etc. I share your curiosity.

I have a P-47N POH and it says the empty weight is 10,998 lbs. and the useful load is anywhere from 2,824 lbs up to 10,200 lbs.

Max fuel internal is 550 US gal. with another 440 US gal. of external fuel possible. So, fuel can run from zero to 990 gallons. So, fuel can run from zero to 3,300 lbs. internally and up to 5,940 lbs if full internal and external fuel is carried. So ... no external and half internal fuel is 1,650 lbs. Pilot is 200 lbs. 

It had eight 50-cal MG and COULD carry 500 rpg, but the usual load was 267 rpg.

Clean wing, with racks only, it came in at 16,400 lbs. That included full internal fuel. Since half fuel is 1,650 lbs, the same aircraft at half fuel, still with full ammunition is about 14,750 lbs. Figure we used a little oil and a bit of ammo, and we're looking at 14,300 - 14,500 lbs when about to head for home, assuming that is about when we have half internal fuel remaining.

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## Clayton Magnet (Oct 5, 2022)

Shortround6 said:


> Basically what the Japanese had was gun/rocket launcher that with 1/2 the velocity of the German MK 108, fired a bit slower, and a shell that had about 2/3rds of the explosive.
> And the magazine held 10 rounds. weapon could empty the magazine in in about 1.25 seconds.


Seems like it was a missed opportunity for a technology transfer, like the U Boat stuffed full of MG 151/20's for the Ki-61 program.
Easier said than done, I suppose


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## AerialTorpedoDude69 (Oct 5, 2022)

GregP
The optional armament listed in the TAIC manual is confusing and, add to that confusion, it would make sense if an interceptor were well armed. However, 4x12.5mm was what the Japanese Army in 1940 considered to be well armed.  At one point, they considered 2x12.5 and 2x7.8mm to be heavily armed as indicated by the Ki-61 and Ki-44-I.

In the J2M vs Ki-44 comparison, one thing worth pointing out is the time frame: These planes are products of the year in which they were designed and manufactured. And I gotta say it's slightly unfair to compare the J2M3 to the Ki-44-II as there is at least a year separating the two. The fairest comparison is to compare the Ki-44-II to the J2M1 as they are both produced in 1942. However, that comparison is when things get weird. Because while the J2M1 had an advanced airframe, its performance lagged behind that of the Ki-44-II although both have similar horsepower, armaments, and armor protection. For whatever reason, the J2M1 weighs substantially more than the Ki-44-II, both in empty and gross weights. (Its gross weight is more comparable.)

And that potentially contributed to the performance gap between the two, despite the Raiden's use of an extension shaft, advanced streamlining, and a "laminar" airfoil. Only the Mustang or maybe the Tempest use so many aerodynamic refinements (although their superlative performance is partly due to their turbo better supercharger. The Ki-44, on the other hand, is a more conventional design, without much attention to detail. So you might think it would perform worse.

But in a head-to-head comparison between the two aircraft, it's surprising that the Ki-44-II cost less to make, performed better, and weighed less while offering the same armor protection and a similar armament.

But so while I appreciate the J2M1's advanced design, we've got to think that something is extremely wrong with the way the Japanese calculate VMAX on their aircraft. Because these two aircraft had approximately equal horsepower ratings at altitude and ended up with the Raiden (Mk.1) being substantially slower than the Ki-44-II. That doesn't make any sense to me. By the way, thanks for your head-to-head comparison between the two aircraft. It helped summarize the differences between the two aircraft.


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## tomo pauk (Oct 5, 2022)

AerialTorpedoDude69 said:


> Only the Mustang or maybe the Tempest use so many aerodynamic refinements (although their superlative performance is partlye due to their turbo).



There is no turbo on Mustang, nor on Tempest.

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## GregP (Oct 5, 2022)

AerialTorpedoDude69 said:


> GregP
> The optional armament listed in the TAIC manual is confusing and, add to that confusion, it would make sense if an interceptor were well armed. However, 4x12.5mm was what the Japanese Army in 1940 considered to be well armed.  At one point, they considered 2x12.5 and 2x7.8mm to be heavily armed as indicated by the Ki-61 and Ki-44-I.
> 
> In the J2M vs Ki-44 comparison, one thing worth pointing out is the time frame: These planes are products of the year in which they were designed and manufactured. And I gotta say it's slightly unfair to compare the J2M3 to the Ki-44-II as there is at least a year separating the two. The fairest comparison is to compare the Ki-44-II to the J2M1 as they are both produced in 1942. However, that comparison is when things get weird. Because while the J2M1 had an advanced airframe, its performance lagged behind that of the Ki-44-II although both have similar horsepowers, armaments, and armor protection. For whatever reason, the J2M1 weighs substantially more than the Ki-44-II, both in empty and gross weights. (Its gross weight is more comparable.)
> ...



Hi AerialTorpedoDude. 

Somehwat agree, but neither the Mustang nor the Tempest had a turbosupercharger, They were supercharged and, in the case of the P-51D, a 2-stage unit. The Sabre-powered Tempest V had a single-stage, 2-speed supercharger. The Centaurus powered Tempest also had a single-stage, 2-speed supercharger.

An empty Radien comes in at about the normal gross of the Ki-44. That much extra weight without a corresponding power increase accounts for the early performance of the Raiden. Nothing like power to help performance, is there?

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## BiffF15 (Oct 5, 2022)

GregP said:


> That's a problem with a LOT of WWII comparisons. The U.S.A. has a lot of data about their planes while some of the basic data about Axis aircraft are seemingly lifted from one website to the next, verbatim. And the lack of things like standard climb from SL to 10,000 and 20,000 feet or a standard metric number of meters makes comparisons difficult and/or almost impossible. If we DO get decent data in some area, then we seemingly fight over fuel quality, etc. I share your curiosity.
> 
> I have a P-47N POH and it says the empty weight is 10,998 lbs. and the useful load is anywhere from 2,824 lbs up to 10,200 lbs.
> 
> ...


GregP,

First, thanks for the info. To be more specific what I'm looking for is the performance of a P47N at weights it would have seen over Japan on a mission with an expected over water RTB. The numbers I keep seeing don't seem to line up with that weight / configuration. I would think the P47N would perform quite a bit better due to shedding tanks, fuel, and water injection before or as the fight develops. The Mustang Me109 comparisons seem to use takeoff weights / speeds / climb rates when in actuality the Mustang engaging Fw's and Me's over Berlin would be much lighter having shed a larger portion of it's weight / drag from jettisoning tanks and burning gas (a greater improvement in it's performance than the aircraft it encounters). As with the Mustang example, the P47N would be the same at "fights on" over the J2M, Ki-44, or any other Imp Japanese fighter.

Cheers,
Biff

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## GregP (Oct 5, 2022)

Almost all the performance tests are at normal gross weight because that is the worst performance you can expect. I'm pretty sure that as a former F-15 pilot, you saw an enormous difference between an F-15 at airshow weight and an F-15 with full armament and tanks / ordnance. Some even flew with conformal tanks, external tanks, and ordnance, didn't they?

The P-47N performance trials over at wwiaircraftperformace.net show the P-47N with an initial rate of climb of 2,200 fpm at 54.5" Hg and 3,200 fpm at 72: Hg WER. Both of those are at 16,330lbs. I am assuming 2,800 hp WER and about 2,200 HP normal.

I will use a standard formula: RC = (33,000 [(PA-PR)/(W)]), where: RC = rate of climb (fpm), PA =Power available (hp), PR = power required for level flight (hp), W = weight (lbs).

If I punch in 2800 hp and 16,300 lbs for weight, I can back into PR using 3,300 fpm RC. PR would equal 1170 hp. Really, it will be less due to propeller efficiency, etc. Now, if I change the weight to 14,300 lbs, the new rate of climb will be about 3,761 fpm. I am assuming you mean rate of climb since speed would be almost the same. I'd expect roll rate to also not change much with weight, unless the initial roll rate was with wing tanks and the new one is clean.

That's sort of a basic first-order approximation, but shouldn't be too far off. The climb will be better at lighter weights, the question is by how much. A real, practicing aeronautical engineer could do better. Maybe Drgondog will chime in here.

The P-47 has a fantastic zoom climb due to weight and a nice climb boost with reduced weight. It was also a decently fast roller.

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## Zipper730 (Oct 5, 2022)

GregP said:


> That's a problem with a LOT of WWII comparisons. The U.S.A. has a lot of data about their planes while some of the basic data about Axis aircraft are seemingly lifted from one website to the next, verbatim. And the lack of things like standard climb from SL to 10,000 and 20,000 feet or a standard metric number of meters makes comparisons difficult and/or almost impossible. If we DO get decent data in some area, then we seemingly fight over fuel quality, etc. I share your curiosity.


Awhile back I did actually write up some basic graphs for aircraft which had manifold pressure settings in several formats.

While I don't have the ability to just crank out huge amounts of data alone to do anything useful: I would imagine the ability to create accurate charts in either metric/imperial format, determine power settings in all formats, and overlay everything onto a graph with marks for both, would be very useful.


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## GregP (Oct 5, 2022)

Creating the charts is easy ... IF you have the data. To me, getting accurate data is the hard part.

It isn't to difficult to convert among manifold pressure units. The U.S.A. used inches of Mercury absolute pressure. The British used pounds per square inch gauge pressure. The Germans used technical atmospheres (ata). 1 ata = 28.958 in Hg. The Japanese and Russian used mm water gauge or mm Hg gauge.

I attached a spreadsheet below to convert among boost units. It is on the first tab, and is number 3). 

Just enter your known boost unit in the orange border cell, and all the cells on the same row will convert to the boost unit shown in the title row. 

It takes longer to write that than to actually look at it and understand it.

Cheers.

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## Shortround6 (Oct 5, 2022)

Zipper730 said:


> determine power settings in all formats



This gets a bit harder 

Unless I miss-understand you.

HP....................MP/in.....................altitude
2000..................54....................0000
2000...............52.5....................2000ft
1800.................53.....................12,500ft
1650.................53.....................21,000ft

R-2800-8 at 2700rpm no RAM.
it is nice information to have when comparing planes but don't read too much into it as changes in the supercharger or gear ratios can throw the pressure to power settings way off.


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## Zipper730 (Oct 5, 2022)

S
 Shortround6


Just to be clear, I don't mean in every pressure format imaginable: I mean in the following

Absolute pressure, inches of mercury; Gauge pressure, PSI; ATA; the Japanese use gauge pressure in millimeters (air, mercury?); and I assume the Soviets used millimeters as well, but I'm not sure what they used.

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## GrauGeist (Oct 5, 2022)

Zipper730 said:


> Absolute pressure, inches of mercury; Gauge pressure, PSI; ATA; the Japanese use gauge pressure in millimeters (air, mercury?);* and I assume the Soviets used millimeters as well, but I'm not sure what they used.*


Greg covered it above:


GregP said:


> The Japanese and Russian used mm water gauge or mm Hg gauge


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## GregP (Oct 6, 2022)

You KNOW it is gauge pressure when they talk about 0.00 psi of boost, because the normal air pressure is always present.

If it really IS a vacuum, the engine won't run!

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## AerialTorpedoDude69 (Oct 6, 2022)

GregP
I looked up the J2M1's weight vs the Ki-44-IIB (Otsu). The J2M1 and the Ki-44-IIB have almost identical empty weights:
Ki-44-IIB (Source: _Profile Aircraft: Nakajima Ki-44 Shoki ('Tojo')_ by John Brindley

Maximum Loaded: 6,598 lbs 
Empty: 4,643 lbs
Maximum speed: 376 MPH
J2M1 (Source: _Mitsubishi J2M Raiden Jack_ by Robert Peczkowski)

Maximum Loaded: Unavailable
Empty: 4,830 lbs
Maximum speed: 359 MPH
There is definitely an issue with a lack of standardization between different sources. There's no way the Ki-44-IIB should be faster than the J2M1, J2M2, and J2M3.

There's something else worth mentioning here: the J2M2 has larger fuel and water methanol tanks as well as a slightly different engine compared to the J2M3 Model 21 (according to Peczkowski). Which might explain the performance differences. However, the lack of wing tanks on the J2M2 as well as the lack of a oil cooler scoop makes me think it should have been faster than the J2M3 rather than slower.

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## GregP (Oct 6, 2022)

The source I usually use for checking Japanese stuff is," General View of Japanese Military AIrcraft in the Pacific War," published in Tokyo (Edit: 1953). I own a (Edit: 1955) copy of the text in both Japanese and English. It says the empty weight of a Ki-44 (version unnamed) is 4,643 pounds. 6,107 gross. There is no overweight point published. It quotes the empty weight of the J2M3 at 5,675 pounds. 7,573 gross. 8,599 overweight.

TAIC Manual No. 2 versus the new source: Ki-44: 6,100 versus 6,107. About a wash. J2M3 Gross: 7,320 versus 7,320. Exactly the same. TAIC manual No. 2 doesn't HAVE an empty weight for the J2M3. I found a source that said 6,200 pounds but my primary source says 5,675 pounds, with the Raiden 33 being much heavier at 6,259. Methinks I used the empty weight of the Raiden 33 instead of the Radien 21. My fault. When you enter data into a few thousand lines manually, a few mistakes tend to creep in, and my posts have a way of zeroing in on these errors whether or not I'm looking for them.

So, by the "general View" source, a well-respected one to be sure, the J2M3 is actually 22% heavier empty, 24% heavier at gross, and 41% heavier when the J2M3 is at overweight status. While not inconsequential, it might or might not account for performance differences.

The source I used for my post above was, as quoted, TAIC Manual No. 2. I attached it below so you all can see the text for yourself. For Axis aircraft, as well as British, there are some missing data. I went through my own sources to fill in some of the missing data for myself, so I have a document where the main fighter aircraft can be easily compared. The comparisons are only as good as the data and, for SOME Japanese aircraft, the source contradict each other. Which source is correct? Especially since they seem to copy one another, down to using the exact same data, with the same data both present and missing.

So, thanks for pointing out the error in the empty weight of the J2M3 in my document, which has now been corrected. Glad somebody is reading the numbers!

Whatever numbers you post, I can find SOME source that quotes different data. I suppose we all have to decide what we believe. Myself, I think that the comparisons we can draw from the TAIC Manual No, 2 are generally about the same as what we could draw from the "General View" source I use as my backstop. That is, MOST of what we can deduce about one aircraft, compared with what we can deduce about another aircraft, generally agree.

If one source claims one fighter climbs at 4,100 fpm and the other aircraft climbs at 3,100 fpm, then both sources will usually show the better-climbing aircraft having a climb rate about 1/3 greater, regardless of the exact numbers.

Cheers.

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## DarrenW (Oct 13, 2022)

Clayton Magnet said:


> The J2M was a formidable fighter, assuming it was running to spec. And as per this article ( which was posted years prior) was superior to a F6F-5


The author did a notable job dissecting the attributes of both aircraft and I commend him for his scientific approach. But unfortunately he got the F6F-5s service ceiling completely wrong which would skew the results accordingly. On the other hand, he was unusually accurate with the aircraft's other performance statistics which was refreshing to say the least.

Be that as it may, his findings seem to be in line with most aviation historians so there's really nothing new to be found here. The J2M3 was notable for its extraordinary climb rate and with a comparitively low wing loading it could normally out-climb and out-mauever most allied aircraft it encountered at both low and medium speeds.

He did admit that the Hellcat could mostly out-run and out-dive the Raiden, and at high speeds it also held a slight edge in maneuverability.

I would take it one step farther and give an edge in maneuverability at all speeds to the Hellcat, seeing how many Japanese pilots felt that the J2M wasn't a good match for the American fighter in a classic dogfight scenario.

So the "superiority" of the Raiden depended largly on opportunity, along with using its strengths to gain an advantage in combat. But this was also true for the Hellcat and every other fighter used during the war. A proper running J2M3 was hard to find, but if encountered could assuredly give a better account of itself than the obsolete A6Ms and KI-43s still in service by 1945.

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## DarrenW (Oct 14, 2022)

Admiral Beez said:


> Is the IJN the only carrier force to specify a frontline fighter incapable of flying from its carriers? Why not make the Jack carrier capable or divert its resources to a carrier fighter? Since when is it the navy’s job to intercept B-29s? That nation was messed up.


My take on this was that it allowed for an increased performance envelope to be achieved. During WWII carrier fighters tended to be at a slight disadvantage when compared to their land-based rivals due to the constraints of improved low speed handling, airframe strengthening, folding wings, tail/catapult hooks, cockpit visibility, ect. Being land-based from the very start the J2M wasn't affected by any of these parameters so its performance was enhanced as a result.

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## Admiral Beez (Oct 14, 2022)

DarrenW said:


> My take on this was that it allowed for an increased performance envelope to be achieved. During WWII carrier fighters tended to be at a slight disadvantage when compared to their land-based rivals


Japan's A6M carrier fighters were a match for every land-based fighter they met until much later in the war, besting Hawks, Buffaloes, Fokkers, Warhawks, Hurricanes and Spitfires. The A6M was mainly disadvantaged against land-based fighters through obsolescence, as land-based Lightnings and Thuds entered IPTO service.


DarrenW said:


> Being land-based from the very start the J2M wasn't affected by any of these parameters so its performance was enhanced as a result.


Good point, but the IJN‘s carrier fleet could have sure used something with the J2M or Kawanishi N1K’s performance during the later fleet engagements. Presuming of course that pilot training/ability kept up with the competition - otherwise it's all Turkey Shoots no matter that aircraft the IJN fields.


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## DarrenW (Oct 14, 2022)

Admiral Beez said:


> Japan's A6M carrier fighters were a match for every land-based fighter they met until much later in the war,


The Zero was an anomaly for sure but it must be said that it's ascendancy probably had as much to do with tactics employed as it did with any intrinsic qualities of the type. Many land-based fighters of the same era statistically outperformed it to varying degrees, the P-40 and Spitfire being faster, better armed, and both could take far more punishment. Even the oft-maligned P-39 enjoyed a margin of superiority in certain areas. When the allies learned not to fall into the trap of being forced into a slow maneuvering dogfight the Zero began to display some serious flaws.

The J2M was designed as an interceptor and as such speed and climb rate were paramount. Making it carrier-based would most likely be detrimental in this regard so Mitsubishi chose otherwise. After the initial development of the J2M was complete the firm began once again to dedicate it's resources on the development of the A7M Reppu, which had been delayed by work on the J2M. It was expected to be a shipboard fighter and the true successor of the A6M series. When one examines Japan's carrier situation after the brutal campaigns in the Marianas and Philippine Islands, as well as the allied strategic bombing of the homeland occurring simultaneously it's apparent at least to me that they probably made the right choice by developing the Raiden first.

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## Admiral Beez (Oct 14, 2022)

DarrenW said:


> The J2M was designed as an interceptor and as such speed and climb rate were paramount. Making it carrier-based would most likely be detrimental in this regard so Mitsubishi chose otherwise.


Reminds me of the brief for the carrier-based F8F, where climb rate and speed were also paramount. Mind you, Mitsubishi did not have a 2,250 hp P&W R-2800 Double Wasp to call on.

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## FLYBOYJ (Oct 14, 2022)

Admiral Beez said:


> *Japan's A6M carrier fighters were a match for every land-based fighter they met until much later in the war,* besting Hawks, Buffaloes, Fokkers, Warhawks, Hurricanes and Spitfires. The A6M was mainly disadvantaged against land-based fighters through obsolescence, as land-based Lightnings and Thuds entered IPTO service.


I suggest you explore some of the units that were operating within the 5th AF mid/ late 1942. They were holding their own with their P-39s and P-40s, (especially the P-40) of course the game completely changed when they transitioned to the P-38 (late 1942).

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## DarrenW (Oct 14, 2022)

Admiral Beez said:


> Reminds me of the brief for the carrier-based F8F, where climb rate and speed were also paramount. Mind you, Mitsubishi did not have a 2,250 hp P&W R-2800 Double Wasp to call on.


Yes, Mitsubishi could have pursued a shipboard version of the J2M but apparently decided to play it safe. One must remember that Japan didn't have a great amount of resources or time to develop replacement fighter designs, as from Pearl Harbor on they realized they had their backs against the wall.

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## Clayton Magnet (Oct 14, 2022)

DarrenW said:


> After the initial development of the J2M was complete the firm began once again to dedicate it's resources on the development of the A7M Reppu, which had been delayed by work on the J2M


Thankfully they did so.
Had carriers like the Shinano, with a complement of A7M, B7A and C6N actually put to sea when originally envisioned, it would have been a serious headache for the allies

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## Shortround6 (Oct 14, 2022)

Admiral Beez said:


> Reminds me of the brief for the carrier-based F8F, where climb rate and speed were also paramount. Mind you, Mitsubishi did not have a 2,250 hp P&W R-2800 Double Wasp to call on.



And that is a major difference. 

A lot depends on who is responsible for what. 
What was the Imperial Japanese Navy _responsible_ for? 
If it was responsible for naval bases in areas that the Army was not responsible for then having a fast climbing interceptor to defend the bases might have been very important. 
The British in 1938-40 was thinking about a different airplane for base defense than for carrier use, so the Japanese were not alone in this thinking. 

In the US the areas of responsibility were a bit different. The Army had a greater share of the responsibility of naval base defense. 
Navy planes were not going to sit on airbases while they were being attacked but it was the armies job to supply the needed interceptors or at least the bulk of them. .
In the Pacific things got a little mixed up and the Marines did supply land based squadrons but that was after Pearl Harbor.

If the Navy was responsible for air defense of some of the Island bases with no Army air units within support range the answers become different. 

The thought process for the Raiden started in 1938 with the written specification showing up in Sept 1939. Work on the A6M slowed down work so the first prototype didn't fly until March of 1942 but the initial specification (request) called for a speed of 600kph at 6,000 meters, a climb of 5 1/2 minutes to 6,000 meters, a landing speed of 130 kph and a take-off run of 300 meters in zero wind. Some of these are in conflict with each other, especially in 1939-41 with existing or promised engines. 

A carrier fighters needs a bigger wing for lower landing speed and shorter take-off run. A bigger wing means lower top speed and less climb. 
The J2M1 prototypes used 1430hp engines for take-off. They were over 1000lbs heavier than an early A6M. 

Something (or several somethings) had to go. 




Early prototype with small sloped windscreen and the the long extension shaft for the prop. 
Trying to land this thing on a carrier would have been suicidal. But a larger wing, short nosed, tall windscreen fighter wasn't going to come close to the desired speed.

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## tomo pauk (Oct 14, 2022)

DarrenW said:


> Yes, Mitsubishi could have pursued a shipboard version of the J2M but apparently decided to play it safe. One must remember that Japan didn't have a great amount of resources or time to develop replacement fighter designs, as from Pearl Harbor on they realized they had their backs against the wall.



IJN is to blame, IMO, that they specified the _J_2M in the 1st place; '_J_' standing for land-based fighter in the IJN nomenclature. Should've requested another ship-borne fighter instead, and have the land-based version of the A6M outfitted with a more powerful engine for that task. Yes, range/radius will go down, but not as much as it was short on the J2M.

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## Shortround6 (Oct 14, 2022)

tomo pauk said:


> IJN is to blame, IMO, that they specified the _J_2M in the 1st place; '_J_' standing for land-based fighter in the IJN nomenclature. Should've requested another ship-borne fighter instead, and have the land-based version of the A6M outfitted with a more powerful engine for that task. Yes, range/radius will go down, but not as much as it was short on the J2M.


Well, if you are satisfied with a 350-360mph aircraft in 1942/43 you might have gotten it (barely). If you are trying for the 370mph airplane the things are harder.

Or will the A6M with the 1942 Kinsei engine be fast enough? Or do you have to wait for 1943? 

Just opened my new book on Japanese aero engines and it is missing 4 pages right at the end of the Mitsubishi chapter on the pacific war period (all the Mitsubishi engines we are interested in) all but one of the data tables for the Mitsubishi engines.

The Japanese were short on power and tried to substitute aerodynamic tricks 




Some planes could get away with it, some gave more troubles with poor vision or cooling or whatever.

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## AerialTorpedoDude69 (Oct 14, 2022)

Shortround6 said:


> And that is a major difference.
> 
> A lot depends on who is responsible for what.
> What was the Imperial Japanese Navy _responsible_ for?
> ...


A major strategic failing of the IJN was its insistence that all its aircraft have supremely long range. Zeroes (or really any of their carrier aircraft) often doubled as scout aircraft (despite having horrible radios, which limited their effectiveness). This also gave the IJN the advantage of being able to conduct attacks beyond the strike radius of enemy carriers.

The blunder here was that the IJN brass didn't want any of their early-to-mid war frontline aircraft to have even the lowest grade of self-sealing fuel tank, despite objections from designers. The B6N series, for example, could do 2,400 miles as a scout or 1,400 with a full bomb load. It's borderline insane that their most shot-up bombers lacked self-sealing fuel tanks.

As such, the Imperial high command didn't assign much value to carrier-based interceptors with short ranges as they couldn't pull double duty as scouts. This overemphasis on offense and strike power would cost them at Midway, although it also aided the IJN's tactical victories throughout '42 and part of '43.

A Raiden-like interceptor at Midway would have been exceptionally effective at intercepting dive bombers. Except for one thing: its laminar wing would have made for longer take-offs and landings. Which means a Raiden may only have been able to operate from the largest of carriers, if at all. The Raiden's stall speed, with flaps, was something like 92 MPH. A Zero, in comparison, was something like 65 MPH (according to TAIC).
AFAIK, the only "laminar" airfoil to see carrier service during WW2 was on the Japanese C6N Saiun/Myrt. So there may have been some issue adapting low-flow wings to carrier craft.

Getting back to the Tojo-Jack comparison, the Tojo's stall speed (with its non-laminar wing) was around 93 MPH, according to Martin Ferkl. However, other sources list it as being around 85 MPH. I think both could be correct and the higher limit is flaps up. Overall, the Tojo's size and lower landing speed would have made it a better fit for carrier operations.

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## tomo pauk (Oct 14, 2022)

Shortround6 said:


> Well, if you are satisfied with a 350-360mph aircraft in 1942/43 you might have gotten it (barely). If you are trying for the 370mph airplane the things are harder.
> 
> Or will the A6M with the 1942 Kinsei engine be fast enough? Or do you have to wait for 1943?



Seems like the Ki-46-III was flying with water-injected Ha-112-II (a member of the Kinsei family) in December of 1942 as prototype. Talk mid-1943 in-service, 360-370 mph? 
For 1941, the Kinsei 50 series were good for 1100 CV at 6200m ft, as installed eg. on the G3M3 bomber. Sakae 21 on A6M3 in 1941 (1st flight) was good for 980 Cv at 6000 ft, providing the max speed of 545 km/h (339 mph). 
We'd possibly gotten at ~345 mph with the Kinsei 50s, and a few mph more with deletion of hook etc? 
In retrospect, a Zero with the water-injected Kinsei 60 engines in 1943 was no worse than what the IJN had 1944, even if such the Zero is only land-based.

Another engine option is Ha-41, yes, the engine from the competition, as it was the case with Sakae on the Zero.



Shortround6 said:


> Just opened my new book on Japanese aero engines and it is missing 4 pages right at the end of the Mitsubishi chapter on the pacific war period (all the Mitsubishi engines we are interested in) all but one of the data tables for the Mitsubishi engines.



Bummer 
The translated book on the Mitsubishi engines from this forum (thank you, 

 Shinpachi
), as well as the TAIC manual from here are really great assets IMO.



Shortround6 said:


> The Japanese were short on power and tried to substitute aerodynamic tricks
> Some planes could get away with it, some gave more troubles with poor vision or cooling or whatever.



No tricks can be seen on that picture, just a job well done 
Japanese engines have had good power, reliability and low weight, but most of these went into bombers, not fighters.
They also have had hard time figuring out that 1000 HP engines will not cut it, and have persisted for too long on eg. making Zuiseis instead of focusing on the other 2-3 more powerful engines at Mistsubishi (Kinsei, Kasei, as well as Ha-42 of 2000 HP). Going with two licences for the DB 601A was another grave mistake, both Kawasaki and Aichi should've been exclusively making radial engines under licence. Another mistake was ending the Ha-109 engine production.
The J2M with as-is Kasei (ie. no extension shaft) was another missed opportunity.

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## Reluctant Poster (Oct 14, 2022)

AerialTorpedoDude69 said:


> A major strategic failing of the IJN was its insistence that all its aircraft have supremely long range. Zeroes (or really any of their carrier aircraft) often doubled as scout aircraft (despite having horrible radios, which limited their effectiveness). This also gave the IJN the advantage of being able to conduct attacks beyond the strike radius of enemy carriers.
> 
> The blunder here was that the IJN brass didn't want any of their early-to-mid war frontline aircraft to have even the lowest grade of self-sealing fuel tank, despite objections from designers. The B6N series, for example, could do 2,400 miles as a scout or 1,400 with a full bomb load. It's borderline insane that their most shot-up bombers lacked self-sealing fuel tanks.
> 
> ...


The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.

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## Thumpalumpacus (Oct 14, 2022)

Reluctant Poster said:


> The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.



IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.

Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.

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## Admiral Beez (Oct 14, 2022)

AerialTorpedoDude69 said:


> A major strategic failing of the IJN was its insistence that all its aircraft have supremely long range.


What Japan needed was a consolidated fighter for both services. An F4 Phantom II, serving everyone, for example. Impossible because the army and navy couldn't get along.

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## Thumpalumpacus (Oct 14, 2022)

Admiral Beez said:


> What Japan needed was a consolidated fighter for both services. An F4 Phantom II, serving everyone, for example. Impossible because the army and navy couldn't get along.



That certainly would have simplified supply chains. But I think Consolidated was an American company.

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## Reluctant Poster (Oct 14, 2022)

Thumpalumpacus said:


> IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.
> 
> Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.


That was the Japanese system. Radar would have helped immensely but without a "Filter Room' to coalesce the data even radar doesn't do much.


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## Thumpalumpacus (Oct 14, 2022)

Reluctant Poster said:


> That was the Japanese system. Radar would have helped immensely but without a "Filter Room' to coalesce the data even radar doesn't do much.



True enough, the Americans discovered this in the autumn of 1942. Eastern Solomons and especially Santa Cruz were the prime drivers for the implementation of the CIC on ships sized destroyer and larger, to my understanding. American fighter patrols were found to be weak in numbers and often out of position because the radar information wasn't collated and delivered in a timely manner.

Information is great, dissemination is priceless.

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## Shortround6 (Oct 14, 2022)

AerialTorpedoDude69 said:


> Tojo's stall speed (with its non-laminar wing) was around 93 MPH


We really do have to be careful we are comparing the same things. Especially with translations from other languages. 

Stall speeds are often quoted at different weights (full load, mean weight or light) 
but the next step up is often called different things like landing speed or alighting speed .
Which is different from approach speed.

Looking at the reports for the Hurricane I prototype we can find

Stalling speed (weigh not given unless full weight) but with flaps open
Stalling speed with flaps shut (notice not up or down 
Landing speed.
Gliding speed.





Hurricane K-5083 Trials Report


WWII Aircraft Performance, wartime flight trials and reports of Hurricane aircraft. Hurricane data.



www.wwiiaircraftperformance.org




You can find other ones.

Stall speed is exactly that, the plane stalls (stops flying and drops quickly) and is dependent on weight/wing loading and flaps. 

there is sometimes a suggested landing or alighting speed ( just enough extra above stall to allow for control with a margin of error but not so high that the landing run is excessive. 

Landing speed is variable as it may be a somewhat declining speed. You want to cross the fence or threshold with more speed than you touch at so that you don't run out of airspeed too soon. 

Sometimes you have to guess as to what is meant. 

And sometimes landing stall speed is not the same as take-off stall (different flap settings) and if you drop the flaps too much for take-off the increased drag increases you take-off roll.

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## Admiral Beez (Oct 14, 2022)

Thumpalumpacus said:


> That certainly would have simplified supply chains. But I think Consolidated was an American company.


True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84. We might need cats on the carriers though.

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## Shortround6 (Oct 14, 2022)

tomo pauk said:


> No tricks can be seen on that picture, just a job well done


the extended wing screen might have been worth 5-6mph? 

The small openings in the cowlings may have helped speed. No idea if they overheated in climb.
For a recon plane that cruised fast they may have worked very well. 

For a fighter that needed to climb or accelerate after a hard turn maybe not so good. High power and low airspeed sometimes didn't work well 

I would also note that the F6F's canopy height and slope down to the nose not only helped with landings, it allowed higher angle defelection shots before the target got hidden by the cowl, not a problem with recon aircraft

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## Shortround6 (Oct 14, 2022)

Admiral Beez said:


> True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84.


That would require repealing the laws of physics. 
The KI-44 had a 161 sq ft wing and a wing loading of around 37.7 lb/sq/ft.
The Zeros started at 22 lb/sq/ft. ended closer to 26-27lb sq/ft.

BTW that is for the Ki-44 without underwing fuel. You want to take-off and land like a Zero you need around 70-80 more sq ft of wing. 
The bigger wing will weigh around 200-250lbs (or more?) 
A roughly 50% bigger wing will do what to the speed performance? 

The Ki-84 isn't as bad but unless you can fix the engines (and landing gear, and brakes) you don't have a chance of turning it into carrier fighter.

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## GrauGeist (Oct 14, 2022)

Thumpalumpacus said:


> IIRC, at Midway fighter direction consisted of screening cruisers firing in the direction of an incoming wave, at points even using main-battery guns. About as inefficient as one could imagine.
> 
> Hell, if nothing else, orbit one fighter or Kate above KdB, using its long range to stay up for the entire engagement, directing elements from its vantage point at, say, 15-20,000 ASL.


There were several eff-ups regarding the IJN's CAP.
First was too few aircraft, coupled with lack of organization.
When the VTs attacked, all the defenders dove down to intercept, leaving none in place to defend against subsequent attacks. This also caused many of the A6Ms to run low on fuel and ammunition, too.
There wasn't a cohesive schedule between the carriers to provide a balanced rotation and zones for the CAP, either. The rivalry between individual carrier groups was almost on a level of the rivalry between the IJN and IJA.

Add to this, the fleet's scouts were not coordinated, either.

In regards to the surface screen, they were too far out to be of any help with their AA.

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## Thumpalumpacus (Oct 14, 2022)

GrauGeist said:


> There were several eff-ups regarding the IJN's CAP.
> First was too few aircraft, coupled with lack of organization.
> When the VTs attacked, all the defenders dove down to intercept, leaving none in place to defend against subsequent attacks. This also caused many of the A6Ms to run low on fuel and ammunition, too.



Yep, that's why I'd think having a master controller airborne would have been a better solution than the "every man for himself" approach that saw CAP concentrating on one formation to the exclusion of others. To be fair, there's quite a bit of hindsight in my writing this; the Japanese had no idea they'd so thoroughly maul the VTs, and probably thought they needed max force against torpedo planes due to threat.



GrauGeist said:


> There wasn't a cohesive schedule between the carriers to provide a balanced rotation and zones for the CAP, either. The rivalry between individual carrier groups was almost on a level of the rivalry between the IJN and IJA.



I sometimes wonder if it wouldn't have been wiser to keep one or two of their CVs as designated CAP-carriers (with reserve striking forces stowed in the hangar) rather than parceling out the detail in such an uncoordinated matter. There's a fair bit of hindsight on my part there, too.



GrauGeist said:


> Add to this, the fleet's scouts were not coordinated, either.
> 
> In regards to the surface screen, they were too far out to be of any help with their AA.



Well, even if the screen had been tucked in tight, the 25mm cannons they carried in relatively small, early-war numbers probably wouldn't have been much use anyway. It'd also mean that an American torpedo which missed a carrier would perhaps have a chance at striking a cruiser standing by on AA duty.

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## SaparotRob (Oct 14, 2022)

GrauGeist said:


> In regards to the surface screen, they were too far out to be of any help with their AA.


I think one the main strategies for air defense of the IJN CVs was maneuvering. Close in escorts would get in the way.

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## Greg Boeser (Oct 14, 2022)

Shortround6 said:


> Well, if you are satisfied with a 350-360mph aircraft in 1942/43 you might have gotten it (barely). If you are trying for the 370mph airplane the things are harder.
> 
> Or will the A6M with the 1942 Kinsei engine be fast enough? Or do you have to wait for 1943?
> 
> ...


Stop!! this is airplane porn! 
Oooh, Baby! Don't stop!

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## Reluctant Poster (Oct 16, 2022)

Reluctant Poster said:


> The problem with the Zero at Midway wasn't its performance. It had for its era an exceptional rate of climb which is the key parameter. It failed due to a complete lack of a fighter direction system. The USN proved during 1942 that, while their fighter direction system didn't perform up to expectations, an underperforming fighter direction system was much, much better than none at all.


One of the major shortcomings of the F4F, particularly in the F4F-4 version, was its anemic rate of climb. I reviewed the test data for the F4F-4 vs the Zero on the WWII Aircraft Performance website and the difference was astounding. Basically, the Zero could climb to 20,000 feet in little more time than the F4F-4 took to get to 10,000 feet. This is a massive advantage in the interceptor role.






I tried to select the best test I could find for each. F4F-4 is at military power.

The Zero was far and away the best performing shipboard interceptor of 1942 but was sabotaged by the Japanese having no fighter control. I think a case can be made that the Japanese made the correct decision in not providing their fighter pilots with self-sealing fuel tanks and armor (I would not say the same for bombers). As I have pointed out in the past the death rate for Zero pilots wasn't significantly higher than for F4F pilots and the death rate for all fighter pilots in general was much, much lower than that for bomber crew. When defending an extremely high value target like an aircraft carrier a 2 or 3 more dead fighter pilots is more than acceptable if it prevents a bomb from hitting the ship.
The greater endurance of the Zero was theoretically also a great advantage as it allowed greater flexibility in CAP operations. Again, this advantage was largely negated by the Japanese lack of fighter direction.

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## Shortround6 (Oct 16, 2022)

Unfortunately the often listed sources are often at at odds with each other. 

The Zero was a much better at climb that the F4F-4 but something seems off on the F4F figures. 

I would note that the F4F has some problems with military power and normal power. 

Apparently the R-1830 engine in the F4F-4 had problems with inadequate intercooling or inadequate cooling or both. Military power in hi blower was at the same rpm as normal power while in either neutral or low blower it was allowed to run 150rpm higher. 2700rpm instead of 2550rpm. 
The engine was noted as running rough in hi blower at high rpm and there was very little gain in speed (2.5 kts?) and that the carb intake temperature was high (which will increase the cooling load on the engine.) 

A number of charts show the F4F-4 climbing in the low 1000fpm range at 20,000ft, not 900fpm. Now 1200-1300fpm isn't on a par with the Zero but it was not as bad as 900. 
So far the a only chart that shows 900fpm at 20,000 ft is while carrying a pair of drop tanks.

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## XBe02Drvr (Oct 16, 2022)

Reluctant Poster said:


> The Zero was far and away the best performing shipboard interceptor of 1942 but was sabotaged by the Japanese having no fighter control.





Reluctant Poster said:


> The greater endurance of the Zero was theoretically also a great advantage as it allowed greater flexibility in CAP operations. Again, this advantage was largely negated by the Japanese lack of fighter direction.


I remember reading (long ago, I've forgotten where) that if the Japanese had a better understanding of the significance of bonding jumpers, ignition interference suppression, and static discharge systems in * all* radio equipped aircraft, not just long range scouts, Midway and the course of the war in general might have been very different. Apparently, radios from captured Japanese combat aircraft worked just fine on the test bench, but very poorly in flight.

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## Conslaw (Oct 16, 2022)

Admiral Beez said:


> True, true. If the Nakajima Ki-44 can be made carrier-capable without dramatically impacting its performance then the whole IJNAS/IJAF can settle on this one bird. Then both services will move onto the superlative Nakajima Ki-84. We might need cats on the carriers though.


On the other hand, if the IJN and IJA had agreed on a joint service fighter, but if the Army's pull would have resulted in that being the Ki-43 instead of the A6M, The IJN would have ended up with a massively inferior fighter. The Ki-43 in land-based form was both slower and more lightly armed than the A6M. In theory, the Ki-43 would have required extra weight for carrier duty, so the naval version would have performed even worse, maybe losing the Ki-43's outstanding climb rate.


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## FLYBOYJ (Oct 16, 2022)

Conslaw said:


> On the other hand, if the IJN and IJA had agreed on a joint service fighter, but if the Army's pull would have resulted in that being the Ki-43 instead of the A6M, The IJN would have ended up with a massively inferior fighter. The Ki-43 in land-based form was both slower and more lightly armed than the A6M. In theory, the Ki-43 would have required extra weight for carrier duty, so the naval version would have performed even worse, maybe losing the Ki-43's outstanding climb rate.


And "if" it was the other ay around and the JAAF accepted the Zero?

The Ki-43, although slower and lightly armed was no slouch and was reported to be even more maneuverable than the Zero.


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## PAT303 (Oct 16, 2022)

Reluctant Poster said:


> The greater endurance of the Zero was theoretically also a great advantage as it allowed greater flexibility in CAP operations. Again, this advantage was largely negated by the Japanese lack of fighter direction.


 We have a long thread about this, the most important part of a plane is it's pilot, planes can be replaced, experienced pilots cannot and the lack of protection gave the Japanese aircraft long range and good low speed agility but at the cost of everything that made a warplane a warplane. The IJN had some of the most skilled pilots in the air in 1942 but once that top tier was lost the quality was lost with it. As for the endurance, A6M pilots prefered the 20mm cannons and would land as soon as possible once it was expended, as mentioned it in Shattered Sword the carrier decks were kept clear so the CAP fighters could be re-armed as required so having the endurance to fly around and around watching surface ships fire in the direction of incoming attacks to then only have about 10 seconds worth of ammunition for your primary weapons once you engage is not really a war winning strategy. The A6M could have had pilot armor and armoured tanks, even alloy double skin armour like the RAF fighters to protect it's pilot while still having a performance advantage over the F4F.

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## XBe02Drvr (Oct 16, 2022)

PAT303 said:


> The A6M could have had pilot armor and armoured tanks, even alloy double skin armour like the RAF fighters to protect it's pilot while still having a performance advantage over the F4F.


Maybe...but bear in mind, adding those items entails more weight gain than just the added weight of the items themselves. According to his book, Horikoshi and company lightened the airframe to the point it was already stretching minimum safe strength standards at its original design weight. Any increase in weight would require additional structural weight, and the A6M was still at a power disadvantage vs the F4F-4. Also, protecting the fuel tanks both increases weight and reduces capacity. The A6M2 sat atop a very narrow peak of efficiency, which history shows, dropped dramatically when any of its basic parameters were tampered with.

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## PAT303 (Oct 16, 2022)

XBe02Drvr said:


> The A6M2 sat atop a very narrow peak of efficiency, which history shows, dropped dramatically when any of its basic parameters were tampered with.


Which is why I have never rated it, Saburō Sakai is quoted as saying ''no one takes an aerobatics plane to war" when describing the A6M, your response mirrors that.

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## Reluctant Poster (Oct 17, 2022)

PAT303 said:


> We have a long thread about this, the most important part of a plane is it's pilot, planes can be replaced, experienced pilots cannot and the lack of protection gave the Japanese aircraft long range and good low speed agility but at the cost of everything that made a warplane a warplane. The IJN had some of the most skilled pilots in the air in 1942 but once that top tier was lost the quality was lost with it. As for the endurance, A6M pilots prefered the 20mm cannons and would land as soon as possible once it was expended, as mentioned it in Shattered Sword the carrier decks were kept clear so the CAP fighters could be re-armed as required so having the endurance to fly around and around watching surface ships fire in the direction of incoming attacks to then only have about 10 seconds worth of ammunition for your primary weapons once you engage is not really a war winning strategy. The A6M could have had pilot armor and armoured tanks, even alloy double skin armour like the RAF fighters to protect it's pilot while still having a performance advantage over the F4F.


I agree that pilots are hard to replace, and that the Japanese lost a lot of aircrew in 1942. That being said it wasn't the Zero pilots taking the heavy losses, it was the bomber crews. I would agree that the bombers should have been better protected as they had to absorb punishment in order to successfully complete their missions. As I have pointed out in past posts the USN claims for Zeros shot down was greatly exaggerated. The losses suffered were not so significant that a decent training program couldn't have made up the losses, which was the real issue. USN aircrew losses in 1942 were very high as well. The life expectancy of a torpedo bomber crew was basically 1 mission. The difference was that the Americans were training their replacements. The other advantage the American had was their emphasis on air sea rescue. A Japanese pilot who was lost on a strike mission was lost forever, whereas the USN tried to rescue as many as possible. As an example, at Midway, of the 10 pilots from VF-8 that had to ditch 7 were rescued and lived to fight another day. 

According to Lundstrom the Japanese lost 3 AM97 and 13 Zero pilots in air-to-air combat with F4F in 1942 up to and including Miday. The USN lost 7 F4F pilots to Zeros. Some of those Zero pilots could have been rescued. How many of those pilots would have been saved by self-sealing tanks or armor? Plenty of pilots on both sides died after ditching or bailing out. Regardless, the 9 extra dead pilots that may or may not have been saved by better protection is irrelevant in the overall scheme of things. I don't have the numbers, but I would wager the Japanese lost more Zero pilots when their ships were bombed than in the air-to-air combat. I would also wager that they lost more Zero pilots in training.

In any event the real problem wasn't its performance advantage over the F4F, it was the need to climb fast enough to intercept bombers. USN action reports are chock full of complaints about the F4Fs being unable to climb fast enough to intercept before the bombers attacked. Naval fighters had two main roles in 1942 (fighter bombers weren't a thing at that time in naval warfare,) destroying enemy bombers before they could hit your ships and protecting your bombers from being destroyed so that they could sink the enemy. Fighters playing knights of the air jousting with one another was very romantic, but it isn't the real business of war. Fighters existed because bombers existed.

The Japanese were limited in aircraft design due to their lack of powerful engines. They had to make compromises in design and the case can be made that they made the right choices for the Zero. In addition to their fast rate of climb which would have been tremendous advantage in defense if they were properly directed, their long range and great endurance was a big advantage in strike missions.

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## Reluctant Poster (Oct 17, 2022)

Shortround6 said:


> Unfortunately the often listed sources are often at at odds with each other.
> 
> The Zero was a much better at climb that the F4F-4 but something seems off on the F4F figures.
> 
> ...


I tried to pick the best numbers for both aircraft. If you have better data feel free to correct the table.

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## Greg Boeser (Oct 17, 2022)

Both the USN and USMC used F4Fs as fighter bombers in the early days of the war. VMF 211 sank a destroyer and damaged several other ships repelling the first attack on Wake Island. Bomb laden fighters were also used during the early carrier raids against the Marshall Islands, as well as against the Japanese landings at Lea and Salamaua. 
These tactics were dropped when it became obvious that there were not enough shipboard fighters to accomplish all the tasks imagined.

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## Reluctant Poster (Oct 17, 2022)

Greg Boeser said:


> Both the USN and USMC used F4Fs as fighter bombers in the early days of the war. VMF 211 sank a destroyer and damaged several other ships repelling the first attack on Wake Island. Bomb laden fighters were also used during the early carrier raids against the Marshall Islands, as well as against the Japanese landings at Lea and Salamaua.
> These tactics were dropped when it became obvious that there were not enough shipboard fighters to accomplish all the tasks imagined.


i stand corrected.


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## Shortround6 (Oct 17, 2022)

Greg Boeser said:


> Both the USN and USMC used F4Fs as fighter bombers in the early days of the war. VMF 211 sank a destroyer and damaged several other ships repelling the first attack on Wake Island. Bomb laden fighters were also used during the early carrier raids against the Marshall Islands, as well as against the Japanese landings at Lea and Salamaua.
> These tactics were dropped when it became obvious that there were not enough shipboard fighters to accomplish all the tasks imagined.


The bomb laden F4Fs at that stage in the war were using a pair of 100lb bombs. 

The pre-theory was that the bomb laden fighters would be used for AA suppression against the big ships before the dive bombers and torpedo bombers got there.
We all know how well plans worked out when in contact with the enemy 

I Believe (but could very well be wrong) that there was an element of luck with VMF 211 sank the Japanese destroyer. 









Reports differ. Hit on the stern into the depth charge racks which exploded or a hit closer to midships which also resulted in an explosion. 
Destroyers have a large amount of ammo stored in different places and the boiler rooms which take up a lot of space. 
Without the 100lbs the chances of a secondary explosion are very slight. But the 100lb bombs need a secondary explosion to sink even a ship of this size.
Tactics changed fairly soon. F4Fs that were trying to bomb/strafe ships weren't in a good position to hold off Zeros. F4Fs didn't need the drag of the even the small bombs.

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## Greg Boeser (Oct 17, 2022)

Agreed. Which is why by Coral Sea the idea had been abandoned.
The Wake Island defense was a case of "this is the best we can do." Kisaragi sank after fires set off a secondary explosion. What exactly happened will never be known as there were no survivors.
The USN pilots were highly critical of fighters carrying bombs after Lea/Salamaua because the damage potential of the bombs (30 lb. frags) was considered not worth the decrease in performance.


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## PAT303 (Oct 17, 2022)

Reluctant Poster said:


> The other advantage the American had was their emphasis on air sea rescue.


Both the British and American forces went to great lengths to save their pilots, knowing that not only is your aircraft giving you protection against enemy fire as well as having air sea rescue forces looking for you if you are shot down would have an enormous effect on you as a pilot both mentally and physically, RAF pilots all looked upon "stuffy'' Dowding with great affection because of his personal intervention regarding armored windscreens and rear pilot armor, in the Pacific didn't one commander order all his ships to turn their spot lights on so returning pilots could find the fleet in the dark?, men would follow those commanders to hell and back, the Japanese pilots on the other hand knew if they went down no one was coming for them. The Allies used a holistic approach to fighting the war, and the results show the effect of that.


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## Greg Boeser (Oct 17, 2022)

Not only was no-one coming for you, if you did somehow make it back to friendly lines, you could find yourself unwelcome, as it was a huge loss of face for a commander to have to rescind a "posthumous" promotion.

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## GrauGeist (Oct 17, 2022)

The Germans put a great deal of effort into rescuing downed pilots, too.

The Seenotdienst program also included rescue bouys in the channel (often referred to as "lobster pots").

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## PAT303 (Oct 18, 2022)

GrauGeist said:


> The Germans put a great deal of effort into rescuing downed pilots, too.
> 
> The Seenotdienst program also included rescue bouys in the channel (often referred to as "lobster pots").


After the Battle of France the pilots of JG26 demanded that armor is to be fitted to their 109's before they fought over the channel.


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## Snautzer01 (Oct 18, 2022)

GrauGeist said:


> The Germans put a great deal of effort into rescuing downed pilots, too.
> 
> The Seenotdienst program also included rescue bouys in the channel (often referred to as "lobster pots").








Luftwaffe Airfield equipment


Nice pics paul. Not sure, but the one of the He111 might be at Aalborg, Denmark. Wonder what the ceremony in the hangar is? Very interesting shot of some formal occassion. Thanks Terry, Hopfully they will help for some one making a Diarama.



ww2aircraft.net

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## Juha3 (Oct 18, 2022)

PAT303 said:


> Both the British and American forces went to great lengths to save their pilots, knowing that not only is your aircraft giving you protection against enemy fire as well as having air sea rescue forces looking for you if you are shot down would have an enormous effect on you as a pilot both mentally and physically, RAF pilots all looked upon "stuffy'' Dowding with great affection because of his personal intervention regarding armored windscreens and rear pilot armor, in the Pacific didn't one commander order all his ships to turn their spot lights on so returning pilots could find the fleet in the dark?, men would follow those commanders to hell and back, the Japanese pilots on the other hand knew if they went down no one was coming for them. The Allies used a holistic approach to fighting the war, and the results show the effect of that.



As usual it was not so black and white, e.g. after sinking of Shoho the surviving 3 CAP Zeros flew to Deboyne atoll and ditched there because it was arranged that an IJN DD would go there later to check out if there are any survivors and the pilots were rescued.

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## AerialTorpedoDude69 (Oct 18, 2022)

Shortround6 said:


> We really do have to be careful we are comparing the same things. Especially with translations from other languages.
> 
> Stall speeds are often quoted at different weights (full load, mean weight or light)
> but the next step up is often called different things like landing speed or alighting speed .
> ...


You are right and I've over simplified. My basic, low-level understanding of the mechanics isn't great, but Japanese aircraft that were equipped with manuevering flaps always deployed them during landing but I do not think they used them always on take-off. My point was that stall speed is a good-enough proxy for comparing the take-off and landing characteristics of two aircraft. Is the Tojo better suited than the Raiden for carrier operations? Probably, given the comparison in stall speeds (which as you rightfully pointed out, might not have translated well). 


Reluctant Poster said:


> I agree that pilots are hard to replace, and that the Japanese lost a lot of aircrew in 1942. That being said it wasn't the Zero pilots taking the heavy losses, it was the bomber crews. I would agree that the bombers should have been better protected as they had to absorb punishment in order to successfully complete their missions. As I have pointed out in past posts the USN claims for Zeros shot down was greatly exaggerated. The losses suffered were not so significant that a decent training program couldn't have made up the losses, which was the real issue. USN aircrew losses in 1942 were very high as well. The life expectancy of a torpedo bomber crew was basically 1 mission. The difference was that the Americans were training their replacements. The other advantage the American had was their emphasis on air sea rescue. A Japanese pilot who was lost on a strike mission was lost forever, whereas the USN tried to rescue as many as possible. As an example, at Midway, of the 10 pilots from VF-8 that had to ditch 7 were rescued and lived to fight another day.
> 
> According to Lundstrom the Japanese lost 3 AM97 and 13 Zero pilots in air-to-air combat with F4F in 1942 up to and including Miday. The USN lost 7 F4F pilots to Zeros. Some of those Zero pilots could have been rescued. How many of those pilots would have been saved by self-sealing tanks or armor? Plenty of pilots on both sides died after ditching or bailing out. Regardless, the 9 extra dead pilots that may or may not have been saved by better protection is irrelevant in the overall scheme of things. I don't have the numbers, but I would wager the Japanese lost more Zero pilots when their ships were bombed than in the air-to-air combat. I would also wager that they lost more Zero pilots in training.
> 
> ...


I appreciate your commentary and quantitative analysis (and am frankly surprised that anyone agreed with me on this point). By the way, the first dedicated Japanese recon aircraft was the Suisei Type C/Judy, which was first fielded at Midway, ironically. In other words, an aircraft that might have freed up Japanese fighters and bombers from recon duty was available, they just weren't available in large numbers.

I think another failing of the Zero was its 100-round drum with low velocity 20mm. They just didn't have the staying power or range to reliably take down wave after wave of bomber, as (I think) you pointed out earlier. The Tojo's quad 12.7mm would have probably been more effective for breaking up bombing runs at a distance, even though the Japanese 12.7 had shorter range compared to the M2. And while the Tojo's climb to 20k was only a couple minutes better, that might have made the difference between a carrier getting flattened and it escaping with just minor damage.

I've heard the claim that (low level) torpedo bombers were instrumental to success at Midway. But IMO this seems like postwar propaganda which tried to paint what was essentially a suicide mission in a more favorable light. From what I can tell, Torpedo bombers were only great when the ships weren't well defended. Otherwise they tended to be little more than kamikazes flying into a steel maw fanged by large caliber tracers and clouds of flak. As you've mentioned before, 200% agree that a fast climbing interceptor would have been useful during Midway.
Torpedo bombers seemed to have done badly even against the most rudimentary of defenses. While Avengers were able to absolutely crush shipping, they didn't seem to perform as spectacularly when faced against CAP and capital ships. And the Avenger is probably one of the best torpedo bombers of the war. If the real threat to carriers were dive bombers, then rate of climb seems to have been the most important performance stat for interceptors.


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## Shortround6 (Oct 18, 2022)

AerialTorpedoDude69 said:


> I think another failing of the Zero was its 100-round drum with low velocity 20mm. They just didn't have the staying power or range to reliably take down wave after wave of bomber, as (I think) you pointed out earlier. The Tojo's quad 12.7mm would have probably been more effective for breaking up bombing runs at a distance, even though the Japanese 12.7 had shorter range compared to the M2.


The Early Zeros only had 60 rounds of ammo. 

The problem with the Army 12.7 guns is that ran out of ammo fairly quickly also. Nowhere near what the 20mm cannon did but the Japanese Army pretty much standardiezed on 250rpg for the 12.7mm. no real reason they could not have used more except for weight. 
Wing guns were supposed to fire at around 900rpm or 15 rounds per second so you have around 16-17 seconds of firing time. Cowl guns a lot longer but the rate of fire is low.

Problem is you need to get a lot more hits to shoot down the dive/torpedo bombers. 
The Japanese 12.7mm gun had less range because it used a lighter, slower bullet. 
The Japanese HE 12.7mm bullet held about 0.8 grams of HE, the Japanese Navy 20mm guns used shells with 10 grams of HE.
The Japanese 12.7mm non HE bullet had around 60% of the force of an American .50 cal bullet. 

The idea that any fighter could "stand off" and use their guns at long range (or longer than the defensive guns would work) was popular but rather misguided. One of the main limits of accuracy in air to air firing was the time of flight. We don't have good information on the Japanese weapons but the German 7.9mm and 13 mm ammo had times of flight that were only 0.06 seconds apart at 600 meters at sea level (and the 7.9mm was faster). the time was about 1.2 seconds and a 200mph airplane could move about 360ft in 1.2 seconds so you have to be aiming quite a bit ahead at 600 meters or wait to get closer. Firing at long range uses a lot more ammo. 
For the American rear gunners a pair of 1200rpm (2400rpm total) .30 cal guns might have been more effective than a single 800rpm .50 cal. They were also easier to aim.

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## PAT303 (Oct 18, 2022)

Juha3 said:


> As usual it was not so black and white, e.g. after sinking of Shoho the surviving 3 CAP Zeros flew to Deboyne atoll and ditched there because it was arranged that an IJN DD would go there later to check out if there are any survivors and the pilots were rescued.


3 pilots rescued out of how many?, have you looked into what happened to the survivors of the Kutai Butai after they returned to Japan?.


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## PAT303 (Oct 18, 2022)

Reluctant Poster said:


> That being said it wasn't the Zero pilots taking the heavy losses, it was the bomber crews.


It was the grievous injuries sustained by the Luftwaffe bomber crews that resulted in armor being fitted to them.


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## SaparotRob (Oct 18, 2022)

PAT303 said:


> 3 pilots rescued out of how many?, have you looked into what happened to the survivors of the Kutai Butai after they returned to Japan?.


I’m outside so I can’t check my battered copy of Shattered Sword. I believe the book points out that most of the aircrews were picked up. The heavy blow was the loss of the plane handling crews. That was the irreplaceable loss of experience.

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## GregP (Oct 18, 2022)

PAT303 said:


> Which is why I have never rated it, Saburō Sakai is quoted as saying ''no one takes an aerobatics plane to war" when describing the A6M, your response mirrors that.



The A6M was the best carrier fighter in the world in 1941 - 1942, and SHOULD be rated as such. It didn't start to be eclipsed until the Hellcat and Corsair got there. The P-38 was better if you stayed fast, but was not a dogfighter like the A6M.

Writing off the A6M as "no good" is just plain overlooking the fact that it was the best carrier-based fighter until it got eclipsed by the F6F / F4U, etc. and was dangerous when handled by an expert pilot up through the end of the war. By that time, the "expert pilots" weren't exactly numerous, but they were around. Nobody who was there took a Zero lightly, at least according to those pilots flying the planes in WWII. I've heard over 100 speak, and none of them thought the Zero was an "easy target" unless you got it by ambush.

ANY plane is an easy target when it doesn't know there's a fight on.

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## GrauGeist (Oct 18, 2022)

The CAP Zeros being down low and scattered at Midway after trying to intercept the several waves of attacks, including Torpedo bombers is not postwar propaganda, it was fact.

The repeated attacks from Midway, plus the attacks coming from the US Carriers had the Japanese carriers in disarray due to defensive maneuvers, plus the attacks for the most part, were at low to moderate altitudes.
When the SBDs arrived, they were at a much higher altitude and the timing of their arrival put the Japanese fleet's CAP at a disadvantage both because they had been repeatedly pulled down low and were running low on fuel and ammunition because of that.

*IF* IJN CAP doctrine been layed out better, using coordinated zones, rotations, and directed groups, the SBDs may not have delivered such a hard blow to their fleet due to interception.

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## PAT303 (Oct 18, 2022)

GregP said:


> The A6M was the bet carrier fighter in the world in 1941 - 1942, and SHOULD be rated as such.


It was good because everything else was rubbish, the Wildcat/Martlet had good protection, a good radio and tough, once the pilots got over the "Zero Myth" it started to show it's worth but saying you are right, with the arrival of the Hellcat the USN finally had the plane and tactics to end A6M's career.


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## PAT303 (Oct 18, 2022)

GrauGeist said:


> *IF* IJN CAP doctrine been layed out better, using coordinated zones, rotations, and directed groups, the SBDs may not have delivered such a hard blow to their fleet due to interception.


If the Japanese had better radio's, plotting tables and controllers, better AA defence instead of those 25mm things, practised repelling realistic attacks from different directions and heights plus all the things you mentioned they would have maybe done better, but the constant attacks by every type of plane the US had, single engined, twin engined even four engined B17's, plus the marauder?, that tried to Kumakazi one of the carriers seriously rattled the IJN commanders. There was a boatload of courage shown by the US pilots that day not to mention the commanders that showed initiative by going all out putting everything up that day

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## AerialTorpedoDude69 (Oct 18, 2022)

PAT303 said:


> It was good because everything else was rubbish, the Wildcat/Martlet had good protection, a good radio and tough, once the pilots got over the "Zero Myth" it started to show it's worth but saying you are right, with the arrival of the Hellcat the USN finally had the plane and tactics to end A6M's career.


Sorry to butt in. There is a tendency to among aviation enthusiasts to give too much credit to, or not enough credit to, the Zero. It has its weaknesses, which were common to aircraft of the era. But it also had its strengths. Chief among its superlative characteristics were its weight.

The Zero had some extremely advanced technologies packed into it. For example, aluminum 7075 ("extra super duralumin") and its wing being built integral with the fuselage were all examples of unusual technologies being deployed to lighten the Zero. 

The truth was, the Allies didn't have the technology to build an aircraft as light as the Zero. But that was probably by choice as lighter aircraft were nice but nothing was better than reliable, performant, heavily armed, and well protected aircraft in abundance.


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## GregP (Oct 18, 2022)

PAT303 said:


> It was good because everything else was rubbish, the Wildcat/Martlet had good protection, a good radio and tough, once the pilots got over the "Zero Myth" it started to show it's worth but saying you are right, with the arrival of the Hellcat the USN finally had the plane and tactics to end A6M's career.



It doesn't matter why it was so good. For a couple to 3 years, it was the best, regardless of the reason. Acknowledging that should not be difficult since it is true.

And the arrival of the Hellcats wasn't nearly as responsible for the Hellcat's success as was the seasoning of the Hellcat pilots, turning them into veterans who could take advantage of the Hellcat's qualities in battle. Many, in fact likely most, were seasoned flying Wildcats and were definitely ready when the Hellcat performance was available to them.


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## Greg Boeser (Oct 18, 2022)

By the time the F6F shows up, late 1943, the decline in Japanese pilot quality was pronounced. Also, Hellcats never flew where they did not enjoy overwhelming superiority in numbers.


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## PAT303 (Oct 19, 2022)

AerialTorpedoDude69 said:


> The truth was, the Allies didn't have the technology to built an aircraft as light as the Zero


Really?, so the likes of Tank, Mitchel, Smith, Shenstone, Messerschmitt had no idea on aircraft construction?. When the Japanese had their
("extra super duralumin") RR had made their R engine with over 2000hp and Whittle had his jet.


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## PAT303 (Oct 19, 2022)

Greg Boeser said:


> By the time the F6F shows up, late 1943, the decline in Japanese pilot quality was pronounced.


What happens when range and low speed agility is put before pilot safety?, you eventually run out of pilots.

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## PAT303 (Oct 19, 2022)

GregP said:


> Acknowledging that should not be difficult since it is true.


What fighter from any nation followed the A6M's design philosophy?, there's your answer.


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## AerialTorpedoDude69 (Oct 19, 2022)

PAT303 said:


> Really?, so the likes of Tank, Mitchel, Smith, Shenstone, Messerschmitt had no idea on aircraft construction?. When the Japanese had their
> ("extra super duralumin") RR had made their R engine with over 2000hp and Whittle had his jet.


There is a multi-quote feature that can allow you to respond to multiple people in one comment, without having to make multiple separate replies.

For example, when you are reading through the comments, you can left-click on the *+Quote* button beneath each comment. Then, when you are responding, you can left-click on *"Insert quotes...* in order to selectively choose each quote that you'd like to respond to. When you're finished, each of those who you've responded to will be notified of your comment.

But anyway, getting back to your comment, a better way to describe what I'm talking about is investment. In other words, technology is more related to what Japanese leaders chose to throw money at. And for whatever reason, they chose to focus on lighter aircraft, which entailed developing lighter alloys and construction methods. The Allies didn't focus on lighter aircraft, they chose to make their aircraft more powerful, reliable, and mass producible.

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## GrauGeist (Oct 19, 2022)

Every nation had their own design philosophy.
Japan's design for the A6M was world's apart from the Spitfire, whichbwas world's apart from the Bf109 and so on and so on and so on.

By the way, Whittle had his jet engine, which was nothing like Von Ohain's...

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## special ed (Oct 19, 2022)

The elimination of experienced IJN pilots may have been facilitated by a lack of info on the newer USN aircraft and their capabilities distributed to combat units. For example, in the video series "Dogfights", a U.S. naval aviator in his new F6F relates his combat with an experienced IJN pilot who began a vertical climb to to evade what he thought was a standard "Grumman" not realising the F6F was not the familiar F4F which he usually easily out climbed.

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## FLYBOYJ (Oct 19, 2022)

AerialTorpedoDude69 said:


> Sorry to butt in. There is a tendency to among aviation enthusiasts to give too much credit to, or not enough credit to, the Zero. It has its weaknesses, which were common to aircraft of the era. But it also had its strengths. Chief among its superlative characteristics were its weight.
> 
> *The Zero had some extremely advanced technologies packed into it. For example, aluminum 7075 ("extra super duralumin") and its wing being built integral with the fuselage were all examples of unusual technologies being deployed to lighten the Zero.*
> 
> The truth was, the Allies didn't have the technology to build an aircraft as light as the Zero. But that was probably by choice as lighter aircraft were nice but nothing was better than reliable, performant, heavily armed, and well protected aircraft in abundance.


The Zero for it's day, was one of the best fighters in the world but got quickly eclipsed. With that said...

Tell us more about this "extremely advanced technologies packed into it????" Did it offer any breakthroughs in propulsion technologies? Were manufacturing process so advanced it was able to be produced quicker then some of it's contemporaries? Did it carry advanced avionics, radios or ergonomics that enhanced crew performance or survivability?

7075 was developed by the Japanese, a great breakthrough in the world of metallurgy with aviation application, but it wasn't a "silver bullet." There were many similar alloys known to manufacturers that could have been used as a 7075 substitute (magnesium for one but not good for corrosion purposes) if required. Western metallurgists were working on similar alloys in the 7000 series during the 1930s (which meant a combination of Zinc, Magnesium and Copper alloyed with minimal silicon and other impurities), the Japanese were the first to get it "producible." The integral wing was well known and was actually a detriment in the field when you had one wing damaged beyond limits. I've been around restored Zeros and while they had some very clever manufacturing and operational characterizes, the Zero was no wild break through in aviation technology.

The allies "could have and would have" easily constructed an aircraft as alight as the Zero but if you explore what the was being required in western design by those holding the checkbooks, the trend was to go into the opposite direction. Some manufacturers did take up the light weight direction. The rest was history.

















photos via internet

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## soulezoo (Oct 19, 2022)

Let's not forget that the "lightness" of early Japanese aircraft was something of a necessity given the relative low horsepower engines available to them at the time. The original version (A6M1) had a 780 hp engine. Even the A6M2 with the Sakae still had a sub 1000 hp engine. The original specs stated that manuverability will equal the A5M and to achieve that with the engine used the aircraft had to be made as light as possible.

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## GrauGeist (Oct 19, 2022)

The KI-43 was very close to the A6M's specs., too.

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## AerialTorpedoDude69 (Oct 19, 2022)

FLYBOYJ said:


> The Zero for it's day, was one of the best fighters in the world but got quickly eclipsed. With that said...
> 
> Tell us more about this "extremely advanced technologies packed into it????" Did it offer any breakthroughs in propulsion technologies? Were manufacturing process so advanced it was able to be produced quicker then some of it's contemporaries? Did it carry advanced avionics, radios or ergonomics that enhanced crew performance or survivability?
> 
> ...


Thanks for the great comment.
So your examples prove my point. The ultralights, like the CW-21, XP-77, and the C.714 all had empty weights close to (or more than) what the A6M2 Zero weighed, despite haing half the horsepower, being less well armed, having shorter range, etc... because the Allies didn't have the alloys or construction techniques neccessary to build ultra light aircraft. The Italians had the SAI 403 though, although that aircraft's data is not reliable and the horsepower rating is possibly specious for the Delta aircooled. (It's still an amazing aircraft.)

Also, it's true that the Japanese were the first to mass produce 7075. But a little known fact is that Alcoa wasn't able to mass produce it until they had reverse engineered a sample of the metal from a captured Japanese aircraft. Synthesis took place in 1943. Mass production of aircraft-grade metal didn't take place until 1945.

A magic bullet? You might say it was in that it was a breakthrough in materials science. Materials science is generally the hardest area in which to make breakthroughs. But because the Japanese lacked an effective science sharing infrastructure, their breakthroughs generally did not spillover into other industries. So tech like MAD,Yagi radar, etc... kind of never were pursued in the way that they should have been. Japanese alloy technology was never used in the way that it should have been either.

EDIT: Getting back to the main subject, I don't know whether the Tojo or Jack used 7075 in their construction. My understanding is that 7075 was mass manufactured in such quantities that it was in all Japanese aircraft, which would explain why most Japanese aircraft had better power to weight ratios than their contemporaries. (So, yes, a kind of magic bullet, shot from a flimsy gun 😉.)

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## tomo pauk (Oct 19, 2022)

AerialTorpedoDude69 said:


> So your examples prove my point. The ultralights, like the CW-21, XP-77, and the C.714 all had empty weights close to (or more than) what the A6M2 Zero weighed, despite haing half the horsepower, being less well armed, having shorter range, etc... because the Allies didn't have the alloys or construction techniques neccessary to build ultra light aircraft. The Italians had the SAI 403 though, although that aircraft's data is not reliable and the horsepower rating is possibly specious for the Delta aircooled. (It's still an amazing aircraft.)



We can compare the Spitfire I with A6M2. Fully loaded, the former weighted 300 kg more, a good deal of it being that Merlin III was heavier than the Sakae 12 by 110-120 kg, and because of the presence of the liquid cooling system (another 150-200 kg?). Stick the Sakae on the Spitfire I istead of the Merlin it's ancilliaries and now it weights ~2350 kg instead of 2640 kg (5820 lbs) - between the A6M2a (2338 kg) and A6M2b (2421 kg). 
(figures for the Zeros are without the drop tank, source is the Shinpachi's translation)

SAI 403 was good for 575 km/h - see here.

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## FLYBOYJ (Oct 19, 2022)

AerialTorpedoDude69 said:


> Also, it's true that the Japanese were the first to mass produce 7075. But a little known fact is that Alcoa wasn't able to mass produce it until they had reverse engineered a sample of the metal from a captured Japanese aircraft. Synthesis took place in 1943. Mass production of aircraft-grade metal didn't take place until 1945.
> 
> A magic bullet? You might say it was in that it was a breakthrough in materials science. Materials science is generally the hardest area in which to make breakthroughs. But because the Japanese lacked an effective science sharing infrastructure, their breakthroughs generally did not spillover into other industries. So tech like MAD,Yagi radar, etc... kind of never were pursued in the way that they should have been. Japanese alloy technology was never used in the way that it should have been either.


And regardless - this would not have been a game changer. There were plenty of other alloys that were used successfully in aircraft that dominated the Zero so it goes back to the fact that the Zero, although a great performer at the start of the Pacific War was not some leading edge design. It was quickly surpassed in performance and became quickly obsolete.



AerialTorpedoDude69 said:


> EDIT: Getting back to the main subject, I don't know whether the Tojo or Jack used 7075 in their construction. My understanding is that 7075 was mass manufactured in such quantities that it was in all Japanese aircraft, which would explain why most Japanese aircraft had better power to weight ratios than their contemporaries. (*So, yes, a kind of magic bullet, shot from a flimsy gun* 😉.)


Errr, no, not even from a flimsy gun. 7075 offered advantages but wasn't the only reason why "most Japanese aircraft had better power to weight ratios than their contemporaries." The design of structure and weight saving design methods (stamped parts, milling some structural components, lightening holes in structure, minimal structural members to achieve maximum G loading, etc.) were part of the equation that helped achieve light weight but effected strength and durability. I can tell you at the end of the day 7075 was not much lighter than 6061 and depending on the application, 6061 was the better material. Bottom line you weren't saving that much weight by using 7075!

So your comment "the Allies didn't have the alloys or construction techniques necessary to build ultra light aircraft" is simply not true. The fact that 7075 was not available to the allies is irrelevant. There were plenty of allied designers who "could have" easily gone into a lightweight design concept but were not directed that way due to the mandate from their customers. 

Lastly, the Zero, like many other Japanese combat aircraft of the period had terrible interchangeability characteristics. I think this included the Tojo and Jack.

Here a comparison of 7075 to 6061 that goes into laymen's explanations









6061 Aluminum vs. 7075 Aluminum - Differences in Properties, Strength and Uses


This article presents a brief comparison of the properties, strength, and applications between 6061 and 7075 aluminum.




www.thomasnet.com

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## GregP (Oct 19, 2022)

Greg Boeser said:


> By the time the F6F shows up, late 1943, the decline in Japanese pilot quality was pronounced. Also, Hellcats never flew where they did not enjoy overwhelming superiority in numbers.



Not too sure about that, Greg. Carriers didn't carry all that many aircraft, and unless it was a major battle, airplanes that ran into each other over open ocean were most like 4 vs 4, 4 vs 8, or 8 vs 8, all flying from carriers. If one side or the other came from a ground base, there might be more on one side. Most often it was 4 vs 4 out over water. The decline in Japanese pilots wasn't nearly as bad in late 1943 as it would be a year later in late 1944, still with 8 months left to fight. 

Add to that the fact that only 2.5% of all WWII combat sorties were flown in Pacific Ocean Areas, and you have very few engagements relative to other areas. The only areas qualifying as reportable "theaters of operation" with fewer combat sorties were Alaska (0.3%) and the stand-alone 20th AF (1.6%) B-29s.

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## Greg Boeser (Oct 19, 2022)

And yet, the Pacific Ocean Area is where the Hellcat gained the majority of it's kills. After the Guadalcanal campaign wrapped up, there was not a lot of carrier action intil the arrival of _Essex. _After a few minor raids, they went out and smothered Wake Island. The Japanese put up 22 fighters to oppose three carrier air groups. I call that overwhelming superiority.

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## AerialTorpedoDude69 (Oct 19, 2022)

FLYBOYJ said:


> And regardless - this would not have been a game changer. There were plenty of other alloys that were used successfully in aircraft that dominated the Zero so it goes back to the fact that the Zero, although a great performer at the start of the Pacific War was not some leading edge design. It was quickly surpassed in performance and became quickly obsolete.
> 
> 
> Errr, no, not even from a flimsy gun. 7075 offered advantages but wasn't the only reason why "most Japanese aircraft had better power to weight ratios than their contemporaries." The design of structure and weight saving design methods (stamped parts, milling some structural components, lightening holes in structure, minimal structural members to achieve maximum G loading, etc.) were part of the equation that helped achieve light weight but effected strength and durability. I can tell you at the end of the day 7075 was not much lighter than 6061 and depending on the application, 6061 was the better material. Bottom line you weren't saving that much weight by using 7075!
> ...


Again, thank you for a thoughtful comment. But you are reading things that I didn't want to write, perhaps because of my unclear writing and bad grammar.

Here's my point: The Zero had advanced technologies in it that the Allies didn't have. I mentioned 7075 because it was just one example. I didn't mention magnesium because it was a much poorer option compared to aluminum. And IIRC it required using electric arc welding to build into airframes and it was more expensive. I'm not sure why you bring it up as it was never adapted to mass manufacturing AFAIK for WW2 aviation... and I can only think of one prototype that used it. 

But I do see your point that there were other lightweight materials that the Allies could have used in a prototype. My point, though, was that the Allied aviation industry was not suited to build ultralight fighters. (Although 

 tomo pauk
did pretty much cripple my argument by mentioning the Spitfire MK I which was only slightly heavier, had more horsepower, etc... although it was at the expensive of firepower, range, etc..)

I did not mean to imply anything about component interchangeability, about 7075 being universally better than other aluminum alloys, or magnesium being a substitute for 7075 and I apologize for having made so many distracting side comments.

To recap, as with all mass produced components that go into an aircraft, 7075 was (just as you say) one of many techniques that the Japanese used to make their aircraft lighter. As I mentioned earlier, the Allies couldn't have built a lighter aircraft because they did not invest resources in it the way the Japanese did. Although I'm sure if the US wanted to, it could have built anything in a lab because they had the technical capacity to do almost anything.

Regarding 7075, according to Horikoshi, IIRC, it was primarily used in wing spars because of its tensile strength and light weight. So it wasn't used in the parts of the aircraft that needed ductility (as you say). But regardless, it was still one of many reasons Japanese aircraft weighed a lot less than Allied ones. (As an aside: I was under the mistaken impression that wing spars need quite a bit of ductility in order to avoid breaking and just going off my basic understanding of flight engineering, am not sure why 7075 received so much credit for being "30% lighter than alternatives" now that I think about it.)

Anyway, one last thing: i just want you to know that I respect your expertise and writing skill on this forum and my comment comes from a place of respect and admiration. Please don't take offense at anything that I've written as that is not my intent.



tomo pauk said:


> We can compare the Spitfire I with A6M2. Fully loaded, the former weighted 300 kg more, a good deal of it being that Merlin III was heavier than the Sakae 12 by 110-120 kg, and because of the presence of the liquid cooling system (another 150-200 kg?). Stick the Sakae on the Spitfire I istead of the Merlin it's ancilliaries and now it weights ~2350 kg instead of 2640 kg (5820 lbs) - between the A6M2a (2338 kg) and A6M2b (2421 kg).
> (figures for the Zeros are without the drop tank, source is the Shinpachi's translation)
> 
> SAI 403 was good for 575 km/h - see here.


Ah, thank you for the link that was amazing.

Regarding comparisons in weight, I don't think fully loaded is the best comparison as the A6M2 carried large amounts of fuel, whereas the Spitfire carried very little even compared to some of its European theater opponents. But even so, it's pretty obvious that the Spitfire was a very lightweight aircraft, as was the BF-109E. So clearly the Japanese construction technology used to achieve light weight wasn't a magic bullet. It just led to slightly lighter power loadings.

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## GregP (Oct 19, 2022)

Greg Boeser said:


> And yet, the Pacific Ocean Area is where the Hellcat gained the majority of it's kills. After the Guadalcanal campaign wrapped up, there was not a lot of carrier action intil the arrival of _Essex. _After a few minor raids, they went out and smothered Wake Island. The Japanese put up 22 fighters to oppose three carrier air groups. I call that overwhelming superiority.



That's very true, but the Hellcats came from carriers for the most part, and weren't all that numerous relative to land-based IJA aircraft. When they DID get into a major battle, a lot of kills came from hitting the carrier defence force right around the carriers. And, in the major battles, that's where you could find 12 vs 12 or even slightly more, but only the Japanese put up ALL their assets and left their carriers defenseless. They never got the change to make that mistake again after Midway because their carrier force never recovered sufficiently to have another major carrier battle.

They lost Akagi, Kaga, and Soryu, leaving only the Hiryu floating. After we lost the Yorktown, the Hiryu was sunk, leaving the Japanese attack force with no carriers that sailed with the original task force. All the planes that were on those carriers were lost, whether they were airworthy or not because they had no place to land. All counted as victories, though the ditched planes were not aerial victories for SBDs.

I don't really know if the majority of F6F victories were over land-based or carrier-based enemy fighters, but I DO know the aerial battles were, for the most part, not very large relative to ETO battles, numbers-wise if only because there were never a large number of either Allied or Japanese aircraft concentrated in any one area. Even IJA land-based units had lower numbers of airplanes, if only due to the fact that the Japanese never built all that many aircraft to start with, relative to U.S. aircraft numbers.

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## FLYBOYJ (Oct 19, 2022)

AerialTorpedoDude69 said:


> Again, thank you for a thoughtful comment. But you are reading things that I didn't want to write, perhaps because of my unclear writing and bad grammar.
> 
> Here's my point: The Zero had advanced technologies in it that the Allies didn't have.


Again, what are they??? (outside the 7075 discussion) If you look at the bigger picture, they really didn't, they just did some things a little differently to achieve their mission goals.


AerialTorpedoDude69 said:


> I mentioned 7075 because it was just one example of an advanced technology. I didn't mention magnesium because it was a much poorer airframe option compared to aluminum. And IIRC it required using arc welding to build into airframes and it was more expensive. I'm not sure why you bring it up as it was never adapted to mass manufacturing AFAIK for WW2 aviation... and I can only think of one prototype that used it. But I do see your point that there were other lightweight materials that the Allies could have used in a prototype. My point, though, was that their aviation industry was not suited to build ultralight fighters. Although
> 
> tomo pauk
> did pretty much cripple my argument by mentioning the Spitfire MK I which was only slightly heavier, had more horsepower, etc... although it was at the expensive of firepower, range, etc..


Again there's nothing specific there. Yes, the discovery and use of 7075 was an achievement but at the end of the day it really wasn't that great of an advancement


AerialTorpedoDude69 said:


> I did not mean to imply anything about component interchangeability, about 7075 being universally better than other aluminum alloys, or magnesium being a substitute for 7075 and I apologize for having made so many distracting side comments.


OK And my point about interchangeability involved finished component parts - a very basic part of aircraft manufacturing that the Japanese seemed not to get right.


AerialTorpedoDude69 said:


> To recap, as with all mass produced components that go into an aircraft, 7075 was (just as you say) one of many techniques that the Japanese used to make their aircraft lighter. As I mentioned earlier, the Allies couldn't have built a lighter aircraft because they did not invest resources in it the way the Japanese did. *I'm sure if the US wanted to, it could have built anything it wanted to.*


And that's the real point - the Allies more than had the means and capability of doing so, the doctrine of aircraft design directed by those at places like Wright Patterson said otherwise


AerialTorpedoDude69 said:


> Regarding 7075, according to Horikoshi, IIRC, it was primarily used in wing spars because of its tensile strength and light weight. So it wasn't used in the parts of the aircraft that needed ductility. But it was one of many reasons why Japanese aircraft weighed a lot less than Allied ones. (I was under the mistaken impression that wing spars need quite a bit of ductility in order to avoid breaking off and just going off my basic understanding of flight engineering, am not sure why 7075 received* so much credit for being "30% lighter than alternatives" now that I think about it.*


And even that statement is a stretch. 7075 is not great to machine so you would have to look at two similar components that can both be machined the same way. Because of stiffness/brittleness of 7075, certain components wouldn't be able to be manufactured in certain applications


AerialTorpedoDude69 said:


> Anyway, one last thing: i just want you to know that I respect your expertise and writing skill on this forum and my comment comes from a place of respect and admiration. Please don't take offense at anything that I've written as that is not my intent.


Many Thanks! 


AerialTorpedoDude69 said:


> Ah, thank you for the link that was amazing.


And again, many thanks!!!


AerialTorpedoDude69 said:


> Regarding comparisons in weight, I don't think fully loaded is the best comparison as the A6M2 carried large amounts of fuel, whereas the Spitfire carried very little even compared to some of its European theater opponents. But even so, it's pretty obvious that the Spitfire was a very lightweight aircraft, as was the BF-109E. So clearly the Japanese construction technology used to achieve light weight wasn't a magic bullet. It just led to slightly lighter power loadings.


Agree!

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## FLYBOYJ (Oct 19, 2022)

AerialTorpedoDude69
Here's a great link that provides a design analysis of the Zeke 32 "Hamp." You will find that it's construction and internal components are pretty contemporary for the technology of the day.



Design Analysis of the Zeke 32 (Hamp - Mitsubishi A6M3)

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## AerialTorpedoDude69 (Oct 19, 2022)

FLYBOYJ said:


> Again, what are they??? (outside the 7075 discussion) If you look at the bigger picture, they really didn't, they just did some things a little differently to achieve their mission goals.
> 
> Again there's nothing specific there. Yes, the discovery and use of 7075 was an achievement but at the end of the day it really wasn't that great of an advancement
> 
> ...


(One of those comments was meant for Tomo btw, sorry for the confusion)
We might have to agree to disagree about the significance of 7075 but a hint as to its significance is that it took the US four years to adapt it to production and that they chose to invest four years of effort in adapting it for mass production.

7075 is still used today, just as you might expect for any advancement in metallurgy. So, to recap, I don't mean "ancient aliens" or something when I say "advanced technology", we're talking about breakthroughs. And while you might trivialize 7075, I prefer to give credit where credit is due.

My understanding (from reading Horikoshi and Sumitomo's report as well as other post-war analyses) is that a combination of labor-intensive construction methods, such as building the wing "integral" with the fuselage, bracket placement, "drilling" out holes (which later Allied aircraft used extensively), early use of flush riveting, and other techniques (see the article for details) led to the Zero being ahead of its time in its deployment of new weight-saving technologies. That didn't mean the Allies never developed them. It just meant that Horikoshi's team were among the first to adopt them.

Getting back to the original discussion, the Tojo vs. Jack, I wish we knew more about whether the technologies used in the Zero were used in the Tojo or Jack. Because Horikoshi was somewhat involved with the Jack, it may be why it used so many "cutting" edge weight saving technologies and why the Tojo was a more conventional aircraft.

EDIT: You dropped in the same link that I linked to in my comment, while i was responding. Great minds think alike?


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## FLYBOYJ (Oct 19, 2022)

AerialTorpedoDude69 said:


> (One of those comments was meant for Tomo btw, sorry for the confusion)
> We might have to agree to disagree about the significance of 7075 but a hint as to its significance is that* it took the US four years to adapt it to production and that they chose to invest four years of effort in adapting it for mass production.*


Again, a great development but not earth shattering.

It was a welcomed technology but again was not a real game changer. the Zero could have used 6061 in many of it's components and at the end of the day came out with the same result IMO.

BTW - the first US military aircraft to use 7075 was the P2V IIRC


AerialTorpedoDude69 said:


> 7075 is still used today, just as you might expect for any advancement in metallurgy. So, to recap, I don't mean "ancient aliens" or something when I say "advanced technology", we're talking about breakthroughs. And while you might trivialize 7075, I prefer to give credit where credit is due.


I'm well aware of 7075 being used today. I have fabricated parts from it, driven rivets into it, and inspected hundreds of machined parts made from it, it’s only one component in the bigger piece of the pie. 7075 was an advancement but I can tell from experience there's nothing magical about it, then or now.


AerialTorpedoDude69 said:


> My understanding (from reading Horikoshi and Sumitomo's report as well as other post-war analyses) is that a combination of labor-intensive construction methods, such as building the wing "integral" with the fuselage, bracket placement, "drilling" out holes (which later Allied aircraft used extensively), early use of flush riveting, and other techniques (see the article for details) led to the Zero being ahead of its time in its deployment of new weight-saving technologies.


The same methods were being used in the United States and Europe during the same time period, the article doesn't mention that. Drillmatic and automatic riveting machines were being designed and introduced in the US during the late 1930 and into the 1940s (I believe the same in the UK and Canada). What was grossly being dismissed was the Japanese ability to manufacture aircraft almost in the same capacity as western manufactures, that was a surprise to some who were very closed minded about Japanese ability during period.


AerialTorpedoDude69 said:


> That didn't mean the Allies never developed them. It just meant that Horikoshi's team were among the first to adopt them.


Not really. Read my previous post. What he accomplished was good, very good, but it wasn’t earth shattering. There were many manufactures that were on par and even ahead of his design team and manufacturing methods. If the methodologies were so great, production should have been on par or exceeding what allied factories were putting out, and I'm talking early in the war.


AerialTorpedoDude69 said:


> Getting back to the original discussion, the Tojo vs. Jack, I wish we knew more about whether the technologies used in the Zero were used in the Tojo or Jack. Because Horikoshi was somewhat involved with the Jack, it may be why it used so many "cutting" edge weight saving technologies and why the Tojo was a more conventional aircraft.


They probably were.


AerialTorpedoDude69 said:


> EDIT: You dropped in the same link that I linked to in my comment, while i was responding. Great minds think alike?


They do, lol! But look into how the zero was constructed and compare it to its contemporaries. There’s no raving advancements there, just a good formula that gave the Japanese a few years of aerial supremacy.

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## GregP (Oct 19, 2022)

One place the Japanese had a lead was aerial torpedoes. Of course, almost the entire world had better torpedoes than we did when WWII started.

The Japanese were able to design an aerial unit that could be dropped into Pearl Harbor without hitting the bottom of the harbor. At the time, U.S. torpedoes were not very good and were never able to be dropped in quite as shallow water.

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## PAT303 (Oct 19, 2022)

soulezoo said:


> Let's not forget that the "lightness" of early Japanese aircraft was something of a necessity given the relative low horsepower engines available to them at the time. The original version (A6M1) had a 780 hp engine. Even the A6M2 with the Sakae still had a sub 1000 hp engine. The original specs stated that manuverability will equal the A5M and to achieve that with the engine used the aircraft had to be made as light as possible.


You raise a good point, the A6M was designed for the low power of the available engines, that caused the design to have limited growth, it was also designed for outstanding agility, trouble is that agility came at a cost of high speed maneuverability, every flight report you read about the A6M will quote exceptional low speed turn performance but heavy controls at 250mph and solid over 300, the opposite to western aircraft.

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## PAT303 (Oct 19, 2022)

AerialTorpedoDude69 said:


> My understanding is that 7075 was mass manufactured in such quantities that it was in all Japanese aircraft, which would explain why most Japanese aircraft had better power to weight ratios than their contemporaries.


Armor protection, SS tanks, navigation/communication equipment, bigger guns, more guns, more ammunition even the life raft added weight, Japanese fighters had better power to weight but it had nothing to do with the alloy they were made from.

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## PAT303 (Oct 19, 2022)

FLYBOYJ said:


> lightening holes in structure,
















There's no better example of the different philosophy's between the Western and Japanese forces. How many of you would pick the Zero seat when .30 .50BMG 20mm SAPI rounds start coming through the rear fuselage?.

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## FLYBOYJ (Oct 19, 2022)

PAT303 said:


> View attachment 691182
> 
> View attachment 691183
> 
> ...


Exactly


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## Shortround6 (Oct 19, 2022)

GregP said:


> One place the Japanese had a lead was aerial torpedoes. Of course, almost the entire world had better torpedoes than we did when WWII started.
> 
> The Japanese were able to design an aerial unit that could be dropped into Pearl Harbor without hitting the bottom of the harbor. At the time, U.S. torpedoes were not very good and were never able to be dropped in quite as shallow water.


The British don't get the credit they should, their torpedoes worked, both airborne and submarine. (problem with magnetic exploders) and the British figured out how to drop them in shallow water about 13 months before Pearl Harbor.

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## PAT303 (Oct 19, 2022)

Shortround6 said:


> The British don't get the credit they should, their torpedoes worked, both airborne and submarine. (problem with magnetic exploders) and the British figured out how to drop them in shallow water about 13 months before Pearl Harbor.


Didn't the Japanese study the Taranto raid as proof of concept before deciding the Pearl Harbor attack was feasible?.

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## GregP (Oct 19, 2022)

Shortround6 said:


> The British don't get the credit they should, their torpedoes worked, both airborne and submarine. (problem with magnetic exploders) and the British figured out how to drop them in shallow water about 13 months before Pearl Harbor.



Maybe they don't get the credit because they didn't have a wildly-successful aerial torpedo attack that took a country out of the war for quite awhile. The Taranto attack in 1940 was pretty well done by Swordfish, true, but the Italian fleet wasn't exactly a huge threat to the UK as the U.S. fleet was seen by Japan. Prior to WWII, the U.S.A. embargoed most raw materials from Japan and we were seen as a threat to Japanese national survival that had to be addressed. The Italians could have made life a bit difficult for the UK, had they chosen to do so, but they weren't a serious threat to national survival of the British Isles.

Still, you hit the nail on the head there, Shortround, the British got it right when they needed to get it right, and also came up with angled flight decks for carriers. They first demonstrated the steam catapult on the HMS Perseus in 1950, with the USS Hancock being the first commissioned carrier to be fitted with the system in 1954. All in all, the Brits have been very much in the forefront of development in many technologies and military advances. I'm glad we're allies!

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## Shortround6 (Oct 19, 2022)

Well they sure screwed up the Italian fleet and altered the balance of power in the Med for quite a while.
They also scored 5 hits for 9 torpedoes dropped (?) which is an excellent percentage. Especially in shallow water and with over 4,000 meters of torpedo nets deployed. 
I don't know how many torpedoes were dropped in clear water and how many had to avoid hitting the bottom and sneak through the opening between the bottom of the nets and mud. An error of a few feet would have stopped the torpedo either way.

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## GregP (Oct 20, 2022)

I said something a couple of pages back I need to retract. I said:

"Not too sure about that, Greg. Carriers didn't carry all that many aircraft, and unless it was a major battle, airplanes that ran into each other over open ocean were most like 4 vs 4, 4 vs 8, or 8 vs 8, all flying from carriers. If one side or the other came from a ground base, there might be more on one side. Most often it was 4 vs 4 out over water. The decline in Japanese pilots wasn't nearly as bad in late 1943 as it would be a year later in late 1944, still with 8 months left to fight.

Add to that the fact that only 2.5% of all WWII combat sorties were flown in Pacific Ocean Areas, and you have very few engagements relative to other areas. The only areas qualifying as reportable "theaters of operation" with fewer combat sorties were Alaska (0.3%) and the stand-alone 20th AF (1.6%) B-29s."

Unfortunately, I used the Statistical Digest of World War II for those numbers and that's a USAAF document. The correct document for Navy statistics is Naval Aviation Combat Statistics World War II, Air Branch, Office of the Chief of Naval Operations, Navy Department, Washington, D.C., OPNAV-P-23V No. A129, 17 June 1946.

The real numbers will have to wait for tomorrow, but it's not really sharp on my part to base Naval numbers on an Air Force document! In reality, the Naval aerial action sorties amounted to a bit over 284,000!

Duhhhh!

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## Juha3 (Oct 26, 2022)

PAT303 said:


> 3 pilots rescued out of how many?, have you looked into what happened to the survivors of the Kutai Butai after they returned to Japan?.


In this case 3 out of 3 IIRC, at least one of them was still around in April 1943 and participated I-GO operation against Guadalcanal.
I checked some 9 Zero aces of Kutai Butai who survived the sinkings and they were transferred to other carriers in July 1942, e.g. to Shokaku, Zuikaku, Junyo, Hiyo and Zuiho.

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## spicmart (Oct 29, 2022)

The Raiden must have been quite an aerodynamically clean airframe. It featured a laminar flow profile wing and although the front section was 20 cm wider in diameter than the Zero's it was less draggy because of the careful shaping of the cowling and windscreen. 
Anybody know more about that?

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## Reluctant Poster (Nov 24, 2022)

Reluctant Poster said:


> I agree that pilots are hard to replace, and that the Japanese lost a lot of aircrew in 1942. That being said it wasn't the Zero pilots taking the heavy losses, it was the bomber crews. I would agree that the bombers should have been better protected as they had to absorb punishment in order to successfully complete their missions. As I have pointed out in past posts the USN claims for Zeros shot down was greatly exaggerated. The losses suffered were not so significant that a decent training program couldn't have made up the losses, which was the real issue. USN aircrew losses in 1942 were very high as well. The life expectancy of a torpedo bomber crew was basically 1 mission. The difference was that the Americans were training their replacements. The other advantage the American had was their emphasis on air sea rescue. A Japanese pilot who was lost on a strike mission was lost forever, whereas the USN tried to rescue as many as possible. As an example, at Midway, of the 10 pilots from VF-8 that had to ditch 7 were rescued and lived to fight another day.
> 
> According to Lundstrom the Japanese lost 3 AM97 and 13 Zero pilots in air-to-air combat with F4F in 1942 up to and including Miday. The USN lost 7 F4F pilots to Zeros. Some of those Zero pilots could have been rescued. How many of those pilots would have been saved by self-sealing tanks or armor? Plenty of pilots on both sides died after ditching or bailing out. Regardless, the 9 extra dead pilots that may or may not have been saved by better protection is irrelevant in the overall scheme of things. I don't have the numbers, but I would wager the Japanese lost more Zero pilots when their ships were bombed than in the air-to-air combat. I would also wager that they lost more Zero pilots in training.
> 
> ...



I did some further research on Lundstrom's books to find out how many more Zero pilots died in due to lack of protection.
At the end of each of his books Lundstrom summarized the performance of the F4F and Zero in combat against each other. Note that his summaries are for USN F4Fs flying from carriers and from Guadalcanal and do not include Marine F4Fs flying from Guadalcanal.

From The First Team (covering the 1st half of 1942)
"_From February through June 1942, the Navy's fighting squadrons shot down seventeen Japanese carrier fighters (three Mitsubishi A5M4 Type 96 carrier fighters and fourteen Zero fighters with sixteen pilots killed), while losing to them in aerial combat only ten Wildcats (seven pilots killed)."_

From Guadalcanal and the First Team (covering the 2nd half of 1942)
_"In strictly fighter vs fighter combat, the ratio of losses was approximately thirty-one Navy F4Fs (twenty-three pilots killed) to twenty-five Zeros."_ F4Fs claimed 54 Zeros overclaiming by more than 2 to 1
Going through Lundstrom's narratives it appears that at least 2 Zero pilots survived leaving 23 Japanese pilots killed.

Ignoring the obsolete Type 96, the results are pretty evenly matched in aircraft shot down with the Zero slightly head at 41 to 39. There is a greater disparity in deaths with the F4F ahead at 36 to 30. In other words, 6 Japanese pilots died who might have survived if Zeros were equipped with self-sealing tanks and armor. That being said some of those Japanese deaths might have been attributable to the poor Japanese rescue service. Also note that a slower, less maneuverable Zero might have resulted in more Zeros being shot down. In any case in the overall scheme of things *6 extra dead pilots* is trivial especially compared to the suffering of bomber aircrews. Further note that 2 of the surviving American pilots were captured by the Japanese, so the net difference in the number of pilots needing to be replaced was actually 4. 75% of F4F pilots shot down died.

Lundstrom's books also show the SBDs supposed mastery of the Zero to be nonsense. He does not do a neat summary of the SBD vs the Zero as he did for the F4F vs Zero so I waded through both books in detail and found that SBDs were over claiming by a factor of about 10 to 1. Out of the 55 claims I have found in his books (11 Type 96s and 44 Zeros) SBDs actually shot down 5 or 6 Zeros (and 0 Type 96s) with fatal consequences to the pilots. The majority of SBD claims were by the rear gunners, which like B-17 gunners were enthusiastic over claimers. As an aside Lundstrom documents several instances of a single B-17 claiming to shoot down 5 or so Zeros when in fact none were shot down. Around 20 false claims were made in these instances.

Lundstrom summarized the Zero's performance in combat as follows:
"_In common with other Japanese aircraft, the Zero lacked pilot armor and self-sealing tanks. Despite these critical drawbacks the high caliber of the Imperial Navy's fighter pilots and the superb performance of the Zero itself rendered combat losses very light."_
This says it all.

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## Reluctant Poster (Nov 24, 2022)

GregP said:


> Maybe they don't get the credit because they didn't have a wildly-successful aerial torpedo attack that took a country out of the war for quite awhile. The Taranto attack in 1940 was pretty well done by Swordfish, true, but the Italian fleet wasn't exactly a huge threat to the UK as the U.S. fleet was seen by Japan. Prior to WWII, the U.S.A. embargoed most raw materials from Japan and we were seen as a threat to Japanese national survival that had to be addressed. The Italians could have made life a bit difficult for the UK, had they chosen to do so, but they weren't a serious threat to national survival of the British Isles.
> 
> Still, you hit the nail on the head there, Shortround, the British got it right when they needed to get it right, and also came up with angled flight decks for carriers. They first demonstrated the steam catapult on the HMS Perseus in 1950, with the USS Hancock being the first commissioned carrier to be fitted with the system in 1954. All in all, the Brits have been very much in the forefront of development in many technologies and military advances. I'm glad we're allies!


A large part of the reason that the Japanese were wildly successful is that they attacked an enemy that didn't know there was a war, a major advantage the British didn't have. Pearl Habor would have been very different against a reasonably alert enemy. The other thing to point out was that Taranto was at night. No other navy or air force in the world had the skill to accomplish what the RN did.


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## AerialTorpedoDude69 (Nov 24, 2022)

Reluctant Poster said:


> A large part of the reason that the Japanese were wildly successful is that they attacked an enemy that didn't know there was a war, a major advantage the British didn't have. Pearl Habor would have been very different against a reasonably alert enemy. The other thing to point out was that Taranto was at night. No other navy or air force in the world had the skill to accomplish what the RN did.


I have to disagree. The US high command weren't fools. They fully expected a war.

To be fair, in 1941 almost everyone on the planet knew war between Japan and the US was imminent, but the expected attack was in the Philippines, not Hawaii. The US even had early warning that an attack was happening but chose to ignore it.

However, even when the US was expecting an attack, thanks to MacArthur, they were not able to adequately defend against the Japanese air raids. MacArthur's micromanagement and poor leadership methods lead to a command chain that was in disarray. They had ignored the radar reports of incoming Japanese strikes and then lost almost all of their air force on the ground. Had MacArthur not been in charge, it's likely they would have held the Philippines for much longer. Perhaps they may have prevented the brutal Japanese occupation? They did have hundreds of aircraft and a numerically larger ground force than the Japanese had.

EDIT: Getting back to the original discussion: Jack vs. Tojo, I did some more reading and the Zero's designer explained why the Japanese favored light-engined aircraft: they were cheaper. There's one big consideration that we haven't been taking into account in this discussion. The Tojo was less expensive to manufacture and develop, compared to the Raiden, which explains the production differences. Based on the evidence, I've got to say that the Tojo's ease of construction (which was incorporated into the Frank) and cheap maintenance is likely what made it a better choice for mass production compared to the Jack. The Jack was just too advanced and too costly to be a reliable field interceptor.

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## GrauGeist (Nov 24, 2022)

AerialTorpedoDude69 said:


> They did have hundreds of aircraft


The FEAF had aircraft, yes.
But how effective against modern Japanese aircraft flown by combat experienced pilots would they be?

This is what the FEAF have in hand on 7 December:
B-17C - 6
B-17D - 29
B-18 - 15

P-26A - 38
P-35A - 38
P-40B/E - 178

O-46A - 2
O-49 - 3
O-52 - 11

Of these "hundreds", quite a few were on the edge of being obsolete and the pilots would have far more determination than experience.

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## Thumpalumpacus (Nov 24, 2022)

AerialTorpedoDude69 said:


> The US even had early warning that an attack was happening but chose to ignore it.



Not only did the American high command have warning signs, they actually issued a war-warning themselves:

_
On November 27th, after delivery of the State Department note of the 26th, but before receipt of the intercepted communications showing the reaction of the Japanese Government, the "war warning" was sent by the Chief of Naval Operations to CinCPac and CincAF. It read:

"This dispatch is to be considered a war warning x negotiations with Japan looking toward stabilization of conditions in the Pacific have ceased and an aggressive move by Japan is expected within the next few days x The number and equipment of Japanese troops and the organization of naval task forces indicate an amphibious expedition against either the Philippines (printed in ink, "Thai") or Kra Peninsula or possibly Borneo x Execute an appropriate defensive deployment preparatory to carrying out the tasks assigned in WPL 46 x Inform district and Army authorities x A similar warning is being sent by War Department x Spenavo inform British x Continental districts Guam Samoa directed take appropriate measures against sabotage"_



XVII. THE WAR WARNING OF NOVEMBER 27th



The surprise at Pearl was not that war had broken out, but that it had broken out at Pearl. Otherwise, the American leadership knew that the shit was about to hit the fan.

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## tomo pauk (Nov 24, 2022)

AerialTorpedoDude69 said:


> EDIT: Getting back to the original discussion: Jack vs. Tojo, I did some more reading and the Zero's designer explained why the Japanese favored light-engined aircraft: they were cheaper. There's one big consideration that we haven't been taking into account in this discussion. The Tojo was less expensive to manufacture and develop, compared to the Raiden, which explains the production differences. Based on the evidence, I've got to say that the Tojo's ease of construction (which was incorporated into the Frank) and cheap maintenance is likely what made it a better choice for mass production compared to the Jack. The Jack was just too advanced and too costly to be a reliable field interceptor.



There are at least two examples of Japanese going against the 'let's buy cheaper stuff'. 
1st is the Ki-45, a 2-engined fighter that managed to combine shortcomings of a 2-engined fighters (much more expensive than 1-engined type, uses double the number of engines than an 1-engined type, it takes longer to make required numbers, it uses much more fuel, big size is giveaway to the enemy) with shortcomings of IJA's 1-engined fighters (indifferent performance, lack of really heavy firepower).
2nd is the Ki-84, that used engine more expensive to make than what 14 cylinder engines of the day cost.

There was a lots of money squandered on aircraft that were supposed to be made in hundreds, too.

A good deal of Jack's problems were due to the choice of complicated powerplant, going simpler would've cost a few mph while also making the fighter more readily available, more reliable and lighter.

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## AerialTorpedoDude69 (Nov 24, 2022)

tomo pauk said:


> There are at least two examples of Japanese going against the 'let's buy cheaper stuff'.
> 1st is the Ki-45, a 2-engined fighter that managed to combine shortcomings of a 2-engined fighters (much more expensive than 1-engined type, uses double the number of engines than an 1-engined type, it takes longer to make required numbers, it uses much more fuel, big size is giveaway to the enemy) with shortcomings of IJA's 1-engined fighters (indifferent performance, lack of really heavy firepower).
> 2nd is the Ki-84, that used engine more expensive to make than what 14 cylinder engines of the day cost.
> 
> ...


Thanks for the response. In the case of the Ki-45, my guess is that the IJA was looking for a multi-role fighter/interceptor and that two Sakae engines was the only way to get the payload/armament that they were looking for. Also, they could have used two Kinsei, but instead opted for the less powerful (but more affordable) Sakae. IMO, it was a bad aircraft, as was its navy counterpart on the basis of its underpowered engines.

My analysis isn't fully consistent with the data, though. By 1942, the Japanese High Command had already been pushing for higher horsepower aircraft, perhaps because of the appearance of more powerful allied aircraft, such as the p-38, P-47 and Corsair. Even so, the Ki-84 was designed from the outset to use fewer parts and cost less than other IJA fighters. Maybe Japanese leaders realized that they couldn't continue to win without faster aircraft but they still knew Japan's limited resources and dependence on imports required a cheaper aircraft? And that would have necessitated bigger engines.



GrauGeist said:


> The FEAF had aircraft, yes.
> But how effective against modern Japanese aircraft flown by combat experienced pilots would they be?
> 
> This is what the FEAF have in hand on 7 December:
> ...


That's a good point. Adding to your point, the Japanese outnumbered the US almost 2-1 in the air. Japan had around 500 aircraft to the US's 270. 
Although I wouldn't call the P-40 obsolete as it was contemporaneous with the Zero and had similar performance. And the later model P-35 weren't total crap either. The Japanese were also flying obsolete aircraft, like the Ki-27, although in numbers similar to the number of Peashooters fielded by the US.

In terms of fighters, there was almost a 1:1 parity. The big difference was in pilot skill whereas the Japanese had many veterns and experienced pilots. Even so, I'm confident that the US would have managed to hold off the Japanese with what they had, even with a bomber-focused tactical dogma dominating their air services.


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## tomo pauk (Nov 24, 2022)

AerialTorpedoDude69 said:


> Thanks for the response. In the case of the Ki-45, my guess is that the IJA was looking for a multi-role fighter/interceptor and that two Sakae engines was the only way to get the payload/armament that they were looking for. Also, they could have used two Kinsei, but instead opted for the less powerful (but more affordable) Sakae. IMO, it was a bad aircraft, as was its navy counterpart on the basis of its underpowered engines.



IJA might've looked at another side of street, and see how Zero has two cannons, it is pretty fast and rangy on half of the number of engines vs. what Ki-45 had.
One Ha-41/-109 can do whatever two Sakaes or Zuiseis can, while being lighter, less draggy, and cheaper to purchase and operate (fuel mileage was a seroius matter in all the Axis countries back in ww2).

IJN, on the other side, can note the fast speed and excellent range of the D4Y, and see how to morph it into a fighter. With a good radial in the nose, a rehash of the fuel tanks, and a pair of cannons it will not be worse than the J1N as a fighter, while again being cheaper to own and use.

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## PAT303 (Nov 24, 2022)

Reluctant Poster said:


> "_In common with other Japanese aircraft, the Zero lacked pilot armor and self-sealing tanks. Despite these critical drawbacks the high caliber of the Imperial Navy's fighter pilots and the superb performance of the Zero itself rendered combat losses very light."_
> This says it all.


No it doesn't, the F4F performance was far below the A6M limiting it's chances of intercepting and attacking at will, against the F6F which did have the performance the A6M was gunned out of the sky. The F4F was similar to the MkV's over Darwin, once they lost the advantage they didn't have the performance to either attack or disengage at their choosing artificially elevation the Zero's invincibility myth, once the Zero met aircraft that could with aggressive pilots that attacked without hesitation it's weaknesses were laid out for all to see.


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## Thumpalumpacus (Nov 24, 2022)

PAT303 said:


> The F4F was similar to the MkV's over Darwin, once they lost the advantage they didn't have the performance to either attack or disengage at their choosing artificially elevation the Zero's invincibility myth, once the Zero met aircraft that could with aggressive pilots that attacked without hesitation it's weaknesses were laid out for all to see.



The Wildcat was not bad in the Solomons. As with any plane, it boils down to how technology, tactics, and doctrine interact.

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## GrauGeist (Nov 24, 2022)

PAT303 said:


> once the Zero met aircraft that could with aggressive pilots that attacked without hesitation it's weaknesses were laid out for all to see.


Unless the A6M had a skilled pilot at the controls.

Nishizawa was downing the best that the Allies could throw at him, right up through 1944.

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## AerialTorpedoDude69 (Nov 24, 2022)

tomo pauk said:


> IJA might've looked at another side of street, and see how Zero has two cannons, it is pretty fast and rangy on half of the number of engines vs. what Ki-45 had.
> One Ha-41/-109 can do whatever two Sakaes or Zuiseis can, while being lighter, less draggy, and cheaper to purchase and operate (fuel mileage was a seroius matter in all the Axis countries back in ww2).
> 
> IJN, on the other side, can note the fast speed and excellent range of the D4Y, and see how to morph it into a fighter. With a good radial in the nose, a rehash of the fuel tanks, and a pair of cannons it will not be worse than the J1N as a fighter, while again being cheaper to own and use.


IIRC, the Ki-45 and Irving were designed to be similar to the Bf-110.

At the time, the Bf-110's twin engine configuration was seen as ideal for a multi-role, long-range escort fighter with larger payload capabilities. But as combat would later prove, the twins tended to be total trash in formation fighting.

Twin engined aircraft _should_ have been a more versatile alternative to a single engined aircraft. The engine nacelles house the landing gear, which makes it easier to support a midwing configuration with greater clearance for bomb loadouts. A single-engined aircraft with equivalent loadout just isn't as easily designed.

In terms of cost, the "Destroyer" was based on inline engines that ouput around 1,200 HP. The japanese versions used a lighter frame but instead had ~1,100 HP Sakae 21 in 1942. And by then the Bf-110 had moved onto 605s. I can't help but feel the Ki-45 and J1N were budget versions of the Bf-110. Lighter, cheaper, and less powerful.

Getting back to the Tojo vs. Jack discussion, I've got to say that the Tojo made a lot more sense than the Jack. It may have been cheaper but that's not neccessarily a bad thing. The Mustang was a relatively cheap aircraft compared to a Spitfire. A Mustang was about equivalent in performance but with an emphasis on being easy to mass produce. The thing cost like half that of a P-47. You'd definitely want to fly a Raiden over a Tojo but from a strategic perspective, the Tojo had a more significant impact on the war compared to the Jack. I've got to change my vote.

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## PAT303 (Nov 24, 2022)

GrauGeist said:


> Unless the A6M had a skilled pilot at the controls.
> 
> Nishizawa was downing the best that the Allies could throw at him, right up through 1944.


The F6F had a 19:1 kill ratio over the A6M, so for every plane Nishazawa downed 19 of his mates went down in return.


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## GrauGeist (Nov 24, 2022)

PAT303 said:


> The F6F had a 19:1 kill ratio over the A6M, so for every plane Nishazawa downed 19 of his mates went down in return.


Like the Luftwaffe, the Japanese pilot pool was losing experience while the aircraft manufacturing could not keep up with loses.

However, the point is, the A6M was still able to defeat the newest of Allied aircraft in the hands of capable pilots.


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## tomo pauk (Nov 25, 2022)

AerialTorpedoDude69 said:


> Getting back to the Tojo vs. Jack discussion, I've got to say that the Tojo made a lot more sense than the Jack. It may have been cheaper but that's not neccessarily a bad thing. The Mustang was a relatively cheap aircraft compared to a Spitfire. A Mustang was about equivalent in performance but with an emphasis on being easy to mass produce. The thing cost like half that of a P-47. You'd definitely want to fly a Raiden over a Tojo but from a strategic perspective, the Tojo had a more significant impact on the war compared to the Jack. I've got to change my vote.



Being cheaper, while doing the same job almost as good as the more expensive A/C is indeed not a bad thing. Tojo was a no-nonsense aircraft, hence it was put in the service earlier and was produced in greater numbers.
Raiden was carrying 2x 20mm cannons, though, and later 4x 20mm.

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## PAT303 (Nov 25, 2022)

GrauGeist said:


> However, the point is, the A6M was still able to defeat the newest of Allied aircraft in the hands of capable pilots.


If it found itself in a favourable position with an experienced pilot flying it and the opposing aircraft politely flew to it's strengths yes the A6M could defeat the newest Allied aircraft, on the other hand if the Allied aircraft decided to not play nicely, fight to it's strength and stayed above 200mph in a maneuvering fight the Zero was gunned down at a ratio of 19:1.


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## FLYBOYJ (Nov 25, 2022)

PAT303 said:


> If it found itself in a favourable position with an experienced pilot flying it and the opposing aircraft politely flew to it's strengths yes the A6M could defeat the newest Allied aircraft, on the other hand if the Allied aircraft decided to not play nicely, fight to it's strength and stayed above 200mph in a maneuvering fight* the Zero was gunned down at a ratio of 19:1.*


"Claims."

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## PAT303 (Nov 25, 2022)

FLYBOYJ said:


> "Claims."


We can only go off the information we have, none of you would pick the A6M over the F6F to fight a war so there's your answer.


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## tomo pauk (Nov 25, 2022)

AerialTorpedoDude69 said:


> IRC, the Ki-45 and Irving were designed to be similar to the Bf-110.
> 
> At the time, the Bf-110's twin engine configuration was seen as ideal for a multi-role, long-range escort fighter with larger payload capabilities. But as combat would later prove, the twins tended to be total trash in formation fighting.



Japanese were not taking the advantages of their 2-engined fighters as much as it was the case for the Western types. Neither Ki-45 nor J1N were adopted to carry some meaningful bomb load like it was the case with Bf 110 or P-38.



AerialTorpedoDude69 said:


> Twin engined aircraft _should_ have been a more versatile alternative to a single engined aircraft. The engine nacelles house the landing gear, which makes it easier to support a midwing configuration with greater clearance for bomb loadouts. A single-engined aircraft with equivalent loadout just isn't as easily designed.


Either a twin-engined aircraft is more versatile, or it should offer the performance overmatch when compared with same generation 1-engined aircraft. Otherwise it is bad use of resources. Japanese twin-engined fighters were lacking both in versatility and in overmatch. Even the guns' firepower was not great for a twin.
Granted, the J1N was rangy.
Unless there is no bomb bay or a fuselage recess for a big bomb or torpedo, a low-wing twin is better than a mid-wing IMO wrt. clearance for bomb loadouts.

There was a number of 1-engined fighters that carried big bombs or were even rated for a torpedo, these loadouts missing from the Japanese 2-engined fighters.

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## tomo pauk (Nov 25, 2022)

PAT303 said:


> We can only go off the information we have, none of you would pick the A6M over the F6F to fight a war so there's your answer.


That choice is not existing before mid-1943. 18-20 months of the war is a very long time.
It is not fault of the Zero that IJN and Japanese aero industry were slow in introducing the next-gen carrier-borne fighter.


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## FLYBOYJ (Nov 25, 2022)

PAT303 said:


> We can only go off the information we have, none of you would pick the A6M over the F6F to fight a war so there's your answer.


You're right but it's still been well established that those numbers are CLAIMS and the actual kill ratio between the F6F and A6M will never be known as with other aircraft that dominated the Zero

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## Shortround6 (Nov 25, 2022)

tomo pauk said:


> Japanese were not taking the advantages of their 2-engined fighters as much as it was the case for the Western types. Neither Ki-45 nor J1N were adopted to carry some meaningful bomb load like it was the case with Bf 110 or P-38.



In some cases the Japanese were 1 to 2 years behind. It took a considerable amount of time to get the Ki-45 sorted out. The Ki-45 was also hindered by it's guns and the distances the JAAF wanted to fly.

Compare the Ki-45 to the Bf 110C. The Ki-45 had two 12.7mm mgs to the 110s four 7.9 guns. Germans did stuff 1000rpg in which was a little excessive. Germans were using the MG/FFM cannon like the ones in the Zero, JAAF didn't have them. They used a heavy 20mm gun that was rather slow firing. 
From an aircraft designer point of view they put in close to the weight of armament that the 110 used (perhaps a little light on ammo). The guns chosen were not as effective as wanted but that is the Armies problem. They are the ones providing the guns. 
The Ki-45 was finally provided with a pair of 250kg bombs, but the 110 only got to carry a pair of 250kg bombs with the C-4/B version which got DB 601N engines, The C-7 got the pair of 500kg bombs but got a stronger undercarriage. As the engines were upgraded in power the 110F came into service with DB 610Fs. Wing racks were into introduced for small bombs. 
with the 110G and the DB 605 engines you could put some big bombs on the 110. Meanwhile the Ki-45 was stuck with same Ha-102 engine it had stared it's service life with in early 1942. granted this was a significate improvement over the 9 cylinder scaled down Mercury engines it started with.

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## tomo pauk (Nov 25, 2022)

Shortround6 said:


> Compare the Ki-45 to the Bf 110C. The Ki-45 had two 12.7mm mgs to the 110s four 7.9 guns. Germans did stuff 1000rpg in which was a little excessive. Germans were using the MG/FFM cannon like the ones in the Zero, JAAF didn't have them. They used a heavy 20mm gun that was rather slow firing.
> From an aircraft designer point of view they put in close to the weight of armament that the 110 used (perhaps a little light on ammo). The guns chosen were not as effective as wanted but that is the Armies problem. They are the ones providing the guns.



Army was also specifying the guns? The MG FFM was firing at higher MV than the FF or the early Zero's cannons. For resons that I'm not aware, seems like Ki-45 was without drop tanks??
I'd like to point out again to what Zero was doing on one engine, and compare it with what Ki-45 was doing on two engines of comparable power. Army could've specified a Zero-sized fighter instead of a twin, powered by Kinsei or Ha-41( or a tad bigger fighter powered by Kasei), to cover the long-range job while sporting at least 4 HMGs. These engines were in series production in 1941.



Shortround6 said:


> The Ki-45 was finally provided with a pair of 250kg bombs, but the 110 only got to carry a pair of 250kg bombs with the C-4/B version which got DB 601N engines, The C-7 got the pair of 500kg bombs but got a stronger undercarriage. As the engines were upgraded in power the 110F came into service with DB 610Fs. Wing racks were into introduced for small bombs.



Petrick and Mankau note up to 2 x 1000 kg bombs already for the 110C-7, and wing drop tanks. The Ki-45 can't compete with the 110 in the payload department.

One wonders whether the Germans and Japanse would've been better of if the Bf 110, Ki-45, Ki-46 and J1N were designed as fast bombers 1st and foremost.



Shortround6 said:


> with the 110G and the DB 605 engines you could put some big bombs on the 110. Meanwhile the Ki-45 was stuck with same Ha-102 engine it had stared it's service life with in early 1942. granted this was a significate improvement over the 9 cylinder scaled down Mercury engines it started with.



Japanese bigger and better engines that might've fit on the Ki-45, like Kinsei or Ha-41, were the types sorely needed for the Zeros and Ki-43s.

Since all of this is slowly getting into what-if territory, I guess I'll bump the Japanese what-if thread here.


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## Shortround6 (Nov 25, 2022)

tomo pauk said:


> Army was also specifying the guns? The MG FFM was firing at higher MV than the FF or the early Zero's cannons. For resons that I'm not aware, seems like Ki-45 was without drop tanks??
> I'd like to point out again to what Zero was doing on one engine, and compare it with what Ki-45 was doing on two engines of comparable power. Army could've specified a Zero-sized fighter instead of a twin, powered by Kinsei or Ha-41( or a tad bigger fighter powered by Kasei), to cover the long-range job while sporting at least 4 HMGs. These engines were in series production in 1941.


The Army tells the aircraft maker what guns they want, not the other way around. For some strange reason the Japanese Army and the Navy hardly ever (if ever) agreed on guns. 
The type 92 7.7mm machine gun may have been the last time. The Zero's cannon were manufactured in a plant owned by ex navy officers. 

The engines used in the Ki-45 were not quite the same power as the as the Zero, subtle but true. The two first Zero prototypes used the Mitsubishi engine that was later used in the Ki-45, but it didn't provide enough power_ at the time_ and Mitsubishi had to use the Nakajima engine. 

The KI-45 after a long and protracted development (they pretty much redesigned the entire airplane) wound up with 1450 liters of fuel in internal tanks. Max range on internal fuel was 1404 miles (long range cruise was 161mph). An empty equipped 110F weighs more than a fully loaded (but clean) Ki-45. Yes the 100C was a lot lighter. A pair of 200 liter drop tanks are listed but I don't know they showed up (or how often) 
The Ki-45 might well have benefited from a change in armament. That modified antitank gun under the belly wasn't doing it any favors in air to air combat. It was almost as powerful as a Hispano but fired a lot slower (rate of fire). 


tomo pauk said:


> Petrick and Mankau note up to 2 x 1000 kg bombs already for the 110C-7, and wing drop tanks. The Ki-45 can't compete with the 110 in the payload department.


True but the C-7 had the 1270hp engines and a beefed up landing gear to handle the weight. 


tomo pauk said:


> Japanese bigger and better engines that might've fit on the Ki-45, like Kinsei or Ha-41, were the types sorely needed for the Zeros and Ki-43s.


Very true. But the very nice 1500hp engines don't show up until 1943/44
Ki-96 prototype using some Ki-45 parts.





Japanese Army could not figure out if they wanted a single seater or a two seater and wasted time bouncing back and forth.

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## Reluctant Poster (Nov 25, 2022)

FLYBOYJ said:


> You're right but it's still been well established that those numbers are CLAIMS and the actual kill ratio between the F6F and A6M will never be known as with other aircraft that dominated the Zero


Agreed. I would also add that the 19 to 1 claim to loss ratio includes ALL Japanese aircraft. The F6F certainly didn't shoot down 5100 Zeros.

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## Shortround6 (Nov 25, 2022)

Reluctant Poster said:


> The F6F certainly didn't shoot done 5100 Zeros.


It didn't ?????

I am shocked, absolutely shocked I tell you. 
The internet is wrong????

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## Reluctant Poster (Nov 25, 2022)

AerialTorpedoDude69 said:


> I have to disagree. The US high command weren't fools. They fully expected a war.
> 
> To be fair, in 1941 almost everyone on the planet knew war between Japan and the US was imminent, but the expected attack was in the Philippines, not Hawaii. The US even had early warning that an attack was happening but chose to ignore it.
> 
> ...


The point is that Pearl Harbor was completely unprepared which was the key to the Japanese success. The brain trust at US high command did a whole lot of nothing to put Pearl Harbor on alert. They did not even put the Philippines on a war footing until after the Pearl harbor raid. As for MacArthur, he knew of the Japanese attack on Pearl harbor before the Japanese had even taken off to attack. He had 9 hours to react in some way.

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## GrauGeist (Nov 25, 2022)

MacArther was stuck between a rock and a hard place.

He was getting orders from the U.S. to mobilize but the President of the Philippines did not want him to for fear if "provoking" the Japanese.

The President had it in his mind that he could negotiate with Tokyo, keeping the Philippines neutral.

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## Reluctant Poster (Nov 25, 2022)

Thumpalumpacus said:


> The Wildcat was not bad in the Solomons. As with any plane, it boils down to how technology, tactics, and doctrine interact.


Lundstrom lists the Marine F4Fs claims at 170.5 with an estimated actual score of 61. The USN was overclaiming by a factor of around 2 while the Marines were a little more enthusiastic at closer to 3.
Lundstrom doesn't summarize Marine F4F losses however the USN Publication "



" lists 75 F4Fs lost in air-to-air combat in WWII. The majority of these would have been lost on Guadalcanal as the last Marine F4F combat mission was flown on April 7, 1943. The Marines did lose 2 F4Fs at Midway. It would appear that the again the Zero held a slight advantage although some of the F4F s may have been lost to bombers. From what I have been able the glean the death rate for the Zero pilots was higher. I was going through the individual combat reports in Lundstrom's book but haven't completed the task.

It should be pointed out that the F4Fs on Guadalcanal held a significant home field advantage. The Zeros were land based and were flying long distance missions that no other single engine fighter could accomplish at that time. In this case the Americans had a tremendous advantage in having an airfield to return to in an emergency. Any damaged Zero had a long way to go to get to safety. A badly damaged Zero either ditched or the pilot bailed out. In addition, the American had an excellent early warning systems in the form of the coast watchers as well as radar which negated the F4Fs very poor climb. The home base also helped the F4F with its short endurance.

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## Thumpalumpacus (Nov 25, 2022)

Reluctant Poster said:


> Lundstrom lists the Marine F4Fs claims at 170.5 with an estimated actual score of 61. The USN was overclaiming by a factor of around 2 while the Marines were a little more enthusiastic at closer to 3.
> Lundstrom doesn't summarize Marine F4F losses however the USN Publication "
> View attachment 696027
> " lists 75 F4Fs lost in air-to-air combat in WWII. The majority of these would have been lost on Guadalcanal as the last Marine F4F combat mission was flown on April 7, 1943. The Marines did lose 2 F4Fs at Midway. It would appear that the again the Zero held a slight advantage although some of the F4F s may have been lost to bombers. From what I have been able the glean the death rate for the Zero pilots was higher. I was going through the individual combat reports in Lundstrom's book but haven't completed the task.
> ...



Right: how technology, tactics, and doctrine interact.


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## PAT303 (Nov 25, 2022)

Reluctant Poster said:


> Agreed. I would also add that the 19 to 1 claim to loss ratio includes ALL Japanese aircraft. The F6F certainly didn't shoot down 5100 Zeros.


I was just making a point about the Japanese Aces being able to mix it with superior aircraft in the Zero, unfortunately they were the only ones..


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## GregP (Nov 25, 2022)

AerialTorpedoDude69 said:


> I have to disagree. The US high command weren't fools. They fully expected a war.
> 
> To be fair, in 1941 almost everyone on the planet knew war between Japan and the US was imminent, but the expected attack was in the Philippines, not Hawaii. The US even had early warning that an attack was happening but chose to ignore it.
> 
> ...



Too advanced and too costly?

Think is was more advanced and more costly than one of the most effective fighters of the war, the P-47, which had a complex turbo-supercharger system and remained one of the most effective fighters produced by anyone during the war?

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## AerialTorpedoDude69 (Nov 25, 2022)

GregP said:


> Too advanced and too costly?
> 
> Think is was more advanced and more costly than one of the most effective fighters of the war, the P-47, which had a complex turbo-supercharger system and remained one of the most effective fighters produced by anyone during the war?


Great point. From the perspective of the strategy that US decision makers pursued, the P-51 offered the Allies a far better cost-to-performance ratio than the P-47, even as remarkable an engineering feat as the P-47 was. I think the P-47 per-mission-loss rate was similar to the Hellcat, which was astoundingly low, but it cost double that of the P-51. I wouldn't put a price on human life so I won't factor in the cost of training a pilot, but if the loss rate was about equal to a P-51, I'd say the P-51 was a more effective aircraft. Would I rather fly a P-51? No way, I'd take the Jug ANY DAY over the 'stang. But in terms of the importance to the war effort, the war planners would probably take the P-51 over the P-47.

And that's probably why there were 2.5 times more Ki-44 aircraft made than the J2M.


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## Just Schmidt (Nov 26, 2022)

The simplest, though not the only, explanation for the greater number og Ki-44's, is that it was earlier, being in production before Pearl Harbour and entering (limited) service shortly after. The J2M was at least a year behind, and then the innovative features caused teething troubles. The Ki-84 and the N1K1-J may be said to be contemporary, so both interceptors had a more all round alternative ready at about the same time. Which one of those that were the most complex I can't say, they both had their share of problems.

As belonging to the navy and army respectively, the relative cost of J2M's and Ki-44's are not directly influenzing which one is recieving priority, but it is indirectly, as their respective alternatives vie for production. Complicating that is that the navy (hoped) it needed fighters able to operate from carriers, otherwise they _may_ have decided to prioritize both the J2M and N1K1-J/2-J higher. The Ki 84 was produced in roughly double the numbers of the Kavanishi fighter.

All that said I think the Ki-44 was better for being out there earlier, though better armament should (and probably could) have been introduced sooner. Had there been less interservice rivalry, we could defenitely have demanded the navy to adopt that design, rather than making their own interceptor. Then, supposing design resources are pooled, _one _late war replacement would be in order. If reason also dictates that there is no N1K1-J but instead the navy adopts the Ki-84 as land based fighter, we may give the job of designing it to Kavanishi.

While I'm at it, drop the Ki-61 and have Kawasaki fokus on getting the Ki-96/ Ki-102 into production as early as possible, so we can bash them instead of the poor Ki-45. Though with two engines, we should get a better bomber destroyer than the A6M, with more range than the Ki-44, and a neat ground attack option available.

But that would be in a world that, at least to me, makes sense as seen through my retroscope.

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## tomo pauk (Nov 26, 2022)

AerialTorpedoDude69 said:


> And that's probably why there were 2.5 times more Ki-44 aircraft made than the J2M.





Just Schmidt said:


> The simplest, though not the only, explanation for the greater number og Ki-44's, is that it was earlier, being in production before Pearl Harbour and entering (limited) service shortly after. The J2M was at least a year behind, and then the innovative features caused teething troubles.



I agree with Just Schmidt - the Ki-44 was manufactured in much greater quantities because it's production started much earlier vs. how the war was long. 
J2M cost to produce was probably lower than of the Ki-84 that used 18 cylinder engine, and certainly lower than the Ki-45 or J1N that were with two engines.



Just Schmidt said:


> If reason also dictates that there is no N1K1-J but instead the navy adopts the Ki-84 as land based fighter, we may give the job of designing it to Kavanishi.



Kawanishi's contribution to the Japanese war effort was severely diluted through many designs they were shelling out, only to be manufactured in meagre numbers; IJN is to blame IMO. So yes - have them designing a 'proper' fighter by 1941, instead of the flights of fantasy like the bespoke floatplane fighter.



Just Schmidt said:


> While I'm at it, drop the Ki-61 and have Kawasaki fokus on getting the Ki-96/ Ki-102 into production as early as possible, so we can bash them instead of the poor Ki-45. Though with two engines, we should get a better bomber destroyer than the A6M, with more range than the Ki-44, and a neat ground attack option available.



Ki-61 with an engine from Ki-96/-102 is the Ki-100. Still very rangy, and unlike the twins, it can be manufactured in quantities required to replace the Ki-43. Japan will have an easier time to fuel 1000 Ki-100s than even 600 Ki-96s/-102s.


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## Reluctant Poster (Nov 26, 2022)

GregP said:


> Too advanced and too costly?
> 
> Think is was more advanced and more costly than one of the most effective fighters of the war, the P-47, which had a complex turbo-supercharger system and remained one of the most effective fighters produced by anyone during the war?


The irony of the P-47 is that the role it is most notable for is ground attack in which the turbocharger was an unnecessary expense and in fact added weight. A Corsair optimized for a land-based role would have been less expensive and in view of the much, much lower take off distance would have required less airfield preparation and without the complexity of the turbocharger maintenance would have been simpler.

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## Reluctant Poster (Nov 26, 2022)

AerialTorpedoDude69 said:


> Great point. From the perspective of the strategy that US decision makers pursued, the P-51 offered the Allies a far better cost-to-performance ratio than the P-47, even as remarkable an engineering feat as the P-47 was. I think the P-47 per-mission-loss rate was similar to the Hellcat, which was astoundingly low, but it cost double that of the P-51. I wouldn't put a price on human life so I won't factor in the cost of training a pilot, but if the loss rate was about equal to a P-51, I'd say the P-51 was a more effective aircraft. Would I rather fly a P-51? No way, I'd take the Jug ANY DAY over the 'stang. But in terms of the importance to the war effort, the war planners would probably take the P-51 over the P-47.
> 
> And that's probably why there were 2.5 times more Ki-44 aircraft made than the J2M.


War is very much about putting a price on human life. Generals make those kinds of decisions all the time.

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## Reluctant Poster (Nov 26, 2022)

Thumpalumpacus said:


> Right: how technology, tactics, and doctrine interact.


It would be interesting to speculate on how Midway would turned out if the Japanese had the equivalent of USN radar and fighter direction.

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## GrauGeist (Nov 26, 2022)

Since Imperial Japan was a maritime empire, it makes sense that they would have floatplane fighter designs early on.

The A6M2-N and N1K1 enabled them the ability to station and operate fighters in remote areas, often times just a protected lagoon.

Of course, as the fortunes of war turned against the Empire, floatplane operations were at risk and the need no longer existed, except for the M6A1, which was designed to operate from carrier subs.

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## FLYBOYJ (Nov 26, 2022)

Reluctant Poster said:


> A Corsair optimized for a land-based role would have been less expensive and in view of the much, much lower take off distance would have required less airfield preparation and *without the complexity of the turbocharger maintenance would have been simpler.*


Unless you can compare the documented maintenance requirements for both aircraft, that's just a guess

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## tomo pauk (Nov 26, 2022)

Reluctant Poster said:


> The irony of the P-47 is that the role it is most notable for is ground attack in which the turbocharger was an unnecessary expense and in fact added weight. A Corsair optimized for a land-based role would have been less expensive and in view of the much, much lower take off distance would have required less airfield preparation and without the complexity of the turbocharger maintenance would have been simpler.



If we want to change the things based on hindsight, outfitting the proper drop-tanks on the P-47 by mid-1943 would've probably give to the P-47s a far better role in the game of destroying the German military assets than it would've been a case if the Allies field yet another fighter-bomber.


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## AerialTorpedoDude69 (Nov 26, 2022)

Lots of great comments here, sorry to only address a few.


Just Schmidt said:


> The simplest, though not the only, explanation for the greater number og Ki-44's, is that it was earlier, being in production before Pearl Harbour and entering (limited) service shortly after. The J2M was at least a year behind, and then the innovative features caused teething troubles. The Ki-84 and the N1K1-J may be said to be contemporary, so both interceptors had a more all round alternative ready at about the same time. Which one of those that were the most complex I can't say, they both had their share of problems.


I have to point out that Ki-44 production also terminated at the end of 1944 and had been slowed since early 1944. On the other hand, Raiden production, which had never been more than a trickle, reached their peak in June of 1944. But even at the peak of Raiden production, almost twice as many Ki-44s were being made. So even with huge demand for Raidens, and Ki-44s being phased out, more Ki-44s were being manufacturered.

IIRC, Allied bombers didn't begin hitting Mitsubishi factories and sub manufacturers until December of 1944. So the reason for Mitsubishi's inability to make more Raidens was (just as you say) multifold. Chief among these factors was the supply shortage caused by Allied raids on Japanese shipping. And the supply shortage is what led to greater emphasis on a cheaper fighter. Something that Japanese war planners had foreseen during the development of the Zero. An island nation that was dependent on imports would have to build cheaper, lighter aircraft if there were ever a disruption of the supply chain.

However, another major reason was that the Raiden and Ki-44 were designed for different purposes. The Ki-44 was designed with the ground war in China in mind. In fact, almost all Ki-44s were sent to Indo-China. The Navy, on the other hand, was still primarily engaged in combat that involved extremely long ranges and therefore a fighter like the Raiden wasn't in demand until Allied bombers were flying with impunity over Japan in the Summer of 1944. There were likely Ki-44s stationed in Northern Japan as well in order to protect against the Kuril and Hokkaido raids, but I know very little about this part of the war.

But more or less, I think you and Tomo are right that price alone wasn't a determining factor, but rather just one factor among many.



tomo pauk said:


> I agree with Just Schmidt - the Ki-44 was manufactured in much greater quantities because it's production started much earlier vs. how the war was long.
> J2M cost to produce was probably lower than of the Ki-84 that used 18 cylinder engine, and certainly lower than the Ki-45 or J1N that were with two engines.


See above for the production numbers relative to Japanese production capabilities. 

Unfortunately, I don't know how much the Kasei 23a production cost versus the Homare 21, but they weighed about the same and the 23a's fuel injection system was undoubtedly more complicated and expensive than a carb system (although the bowl-prime on the Homare 21 was regarded as having elements of a direct injection system). _Maybe _the Homare required more man-hours to produce, but it couldn't have been much more. Otherwise, the Ki-84's total manufacturing costs were supposedly almost half that of a Ki-44 or Ki-43 (IIRC, this is according to Richard Bueschel's book), which themselves were fairly cheap aircraft from a materials standpoint but required massive amounts of manpower to produce, as with all Japanese aircraft.

Keep in mind that a P-51 was like 2,000 man hours and a Spitfire was around 13,000 man hours. While there are no man-hour or cost numbers for a Raiden, we can guess that it was more complicated to build than a Zero based on its weight, extension shaft, and laminar wing. Also, to bolster your point, the Ki-61 had to have been one of the most expensive Japanese aircraft of the war given its weight, its high aspect wing, the absurdedly robust diving speed, and other advanced features and yet the Japanese built around 3,000 of them. Perhaps the Army's military planners were more likely to adopt expensive aircraft given that they didn't have to launch aircraft from carriers?

I can see that my thinking is overly reductionist in this regard. You are right that there is more complexity to Japan's aircraft design paradigm than just cost. Though, I do have some questions about the Ki-61. Like, why? The Ki-44 was available earlier and offered similar performance. It just didn't make sense to make the Ki-61. And on top of that, the Japanese had already added MW50 to a DB601A. The Ki-61 just seemed like too much effort for very little advantage over the Ki-44. And on top of that, the Ki-61 could have been a much better plane with just a little more effort and expense. But that is a conversation for a separate thread.


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## special ed (Nov 26, 2022)

GrauGeist said:


> Since Imperial Japan was a maritime empire, it makes sense that they would have floatplane fighter designs early on.
> 
> The A6M2-N and N1K1 enabled them the ability to station and operate fighters in remote areas, often times just a protected lagoon.
> 
> Of course, as the fortunes of war turned against the Empire, floatplane operations were at risk and the need no longer existed, except for the M6A1, which was designed to operate from carrier subs.


Exactly why floatplane fighters were need in the early years. The Japanese plan was to take as many islands as possible, however the terrain was not always good for building an airstrip. Float fighters, docked at the piers where the supply barges would unload, could easily drive away the PBY recon. As the US took islands with airstrip possibilities, the floatplane became a disadvantage against land based fighters flying within patrol range.

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## GrauGeist (Nov 26, 2022)

special ed said:


> Exactly why floatplane fighters were need in the early years. The Japanese plan was to take as many islands as possible, however the terrain was not always good for building an airstrip. Float fighters, docked at the piers where the supply barges would unload, could easily drive away the PBY recon. As the US took islands with airstrip possibilities, the floatplane became a disadvantage against land based fighters flying within patrol range.


The USN's F4F-3S was developed for the very same reason: deploying to foreward areas that were unimproved. Much like it's Japanese counterparts, the F4F-3S suffered performance penalties due to the floats and only one was made.
The USAAF also considered a P-38E floatplane, but it was never developed.

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## tomo pauk (Nov 26, 2022)

AerialTorpedoDude69 said:


> Otherwise, the Ki-84's total manufacturing costs were supposedly almost half that of a Ki-44 or Ki-43 (IIRC, this is according to Richard Bueschel's book), which themselves were fairly cheap aircraft from a materials standpoint but required massive amounts of manpower to produce, as with all Japanese aircraft.



I'd certainly love to see the manhour totals and/or analysis for the manhour and material cost to make different fighters.



AerialTorpedoDude69 said:


> Keep in mind that a P-51 was like 2,000 man hours and a Spitfire was around 13,000 man hours.


See here for manhours to make P-51s; in October of 1941, it was 12000. Yes, NAA was just starting to make them.
Granted, Spitfire cost in manhours was pretty high. In 1940, 15200 manhours to make one.
Looks like Zero was at 10000 mh mid-war.



AerialTorpedoDude69 said:


> Also, to bolster your point, the Ki-61 had to have been one of the most expensive Japanese aircraft of the war given its weight, its high aspect wing, the absurdedly robust diving speed, and other advanced features and yet the Japanese built around 3,000 of them. Perhaps the Army's military planners were more likely to adopt expensive aircraft given that they didn't have to launch aircraft from carriers?



Ki-61 was IMO nothing special in that regard, rather a simple aircraft. Talk Japanese P-40 or P-51, if lighter?
Ki-45 is when the Japanese went expensive.



AerialTorpedoDude69 said:


> Though, I do have some questions about the Ki-61. Like, why? The Ki-44 was available earlier and offered similar performance. It just didn't make sense to make the Ki-61. And on top of that, the Japanese had already added MW50 to a DB601A. The Ki-61 just seemed like too much effort for very little advantage over the Ki-44.



Ki-61 was a good idea at 1st, but execution of that idea was not. Vs. the Ki-44 it was much rangier and with lower wing loading, just like the IJA loved it. It took too much time for Kawasaski to have what is basically a 1100-1200 HP engine in series production, by what time Japanese in-service radials were at 1500-1800 HP (Allied engines were even better). The Ha 140 was a trainwreck, both in timing and capabilities.
Ki-61 with a radial would've been a far more useful fighter, but that happened way too late.

I'm not sure that Japanese have added water/alcoho injection to the DB 601A of their production, care to elaborate?

Kawasaki making only the radial engines makes far more sense in hindsight, ditto for Aichi.

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## AerialTorpedoDude69 (Nov 26, 2022)

tomo pauk said:


> Ki-61 was a good idea at 1st, but execution of that idea was not. Vs. the Ki-44 it was much rangier and with lower wing loading, just like the IJA loved it. It took too much time for Kawasaski to have what is basically a 1100-1200 HP engine in series production, by what time Japanese in-service radials were at 1500-1800 HP (Allied engines were even better). The Ha 140 was a trainwreck, both in timing and capabilities.
> Ki-61 with a radial would've been a far more useful fighter, but that happened way too late.
> 
> I'm not sure that Japanese have added water/alcoho injection to the DB 601A of their production, care to elaborate?


Both Germany and Japan had been experimenting with adding MW50 to the DB-601A. I think in Germany they had added it to submodels of the DB-605. The Japanese modded a 601A in the 30s to incorporate MW50, predating the German use of MW50 in the 600 series by several years.

I can't help but feel that with better aerodynamic design of the wing and MW50, the Ki-61 could have been a much better fighter, with little more investment from the Japanese.
BTW, a Ki-63 in 1942 would have been a pretty outstanding aircraft. Probably superior to a Ki-61 with laminar wing and MW50 in cost and performance.


tomo pauk said:


> Ki-61 was IMO nothing special in that regard, rather a simple aircraft. Talk Japanese P-40 or P-51, if lighter?
> Ki-45 is when the Japanese went expensive.


Is the only expensive thing about the Ki-45 that it had two (Sakae or Zuisei, which weren't exactly high-end) engines? I think perhaps the wing design is also more expensive as well but otherwise, it does not strike me as being all that advanced an aircraft. I wonder how it would have performed with two Kasei 23a engines.

Bombers are perhaps better examples of expensive designs as they all weigh more and cost more than the Nick. But that is their designed role. There's a reason why the Japanese didn't make heavy bombers: they cost too much.


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## GrauGeist (Nov 26, 2022)

AerialTorpedoDude69 said:


> I can't help but feel that with better aerodynamic design of the wing and MW50, the Ki-61 could have been a much better fighter, with little more investment from the Japanese.


The KI-61 did become a much better fighter when they changed the engine.

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## tomo pauk (Nov 26, 2022)

AerialTorpedoDude69 said:


> The Japanese modded a 601A in the 30s to incorporate MW50, predating the German use of MW50 in the 600 series by several years.


Interesting.
Do you have some good source about the Japanese modding the 601A with MW 50 in the 30s?



AerialTorpedoDude69 said:


> I can't help but feel that with better aerodynamic design of the wing and MW50, the Ki-61 could have been a much better fighter, with little more investment from the Japanese.
> BTW, a Ki-63 in 1942 would have been a pretty outstanding aircraft. Probably superior to a Ki-61 with laminar wing and MW50 in cost and performance.



A fighter with 12m wingspan and Zuisei (even if it is the best version available) does not strike me as a performer. Perhaps comparable with mid-line Zeros and Oscars?
Wing on the Ki-61 was nothing special ( NACA 2R profile,16% t-t-c at root), so there a laminar wing or a 'classic' thin wing is certainly an improvement. MW 50 is certainly a boon, especially when the high-octane fuel is as good as impossible to get; MW 50 is of no help at high altitude unless the supercharger is also good for high altitudes (the Ha 40 and DB 601A have had a mediocre S/C past 1940).



AerialTorpedoDude69 said:


> Is the only expensive thing about the Ki-45 that it had two (Sakae or Zuisei, which weren't exactly high-end) engines? I think perhaps the wing design is also more expensive as well but otherwise, it does not strike me as being all that advanced an aircraft. I wonder how it would have performed with two Kasei 23a engines.



We can take a look at USAAF aircraft, yearly averages for complete aircraft (ready for service, with guns, radios). In 1943, USA were paying for P-40 $49449, and for a V-1710 $11268. For a P-51, $58824 and for a V-1650 (average price is for cheaper -1 and more expensive -3) $16919. Add a prop and cooling systems and the total powerplant percentage is easily around 30% of the whole aircraft, or perhaps 13-14K US$ on a P-40 and ~20K US$ on a P-51. Just the engine itself was perhaps single most expensive part of the aircraft?
V-1710 being cheaper than the R-2600, let alone the R-2800, if more expensive (and more capable) than the R-1830s the AAF was buying. In 1944, V-1710 (includes 1-stage and 2-stage versions; P-38 used 1-stage engine) went down to $10561, while the R-2600 went to above $15000.

A 2-engined aircraft will also have a bigger fuselage, bigger undercarriage, bigger and more elaborate fuel system, usually a cockpit for another crew member - all the things driving the price up. 
The A-20 was a lowest priced USAAF attacker that I know the price of. In 1943 the average cost was $110324, with two R-2600 on average being $26902 (2 x 13451); again, add propellers and oil cooling system and the powerplant price is easy at $30000 on a $11000 aircraft.

tl;dr: number of engines was a big factor in the price paid for the end product; two smaller engines usually cost more than one big engine of similar layout, construction and technological level; from the Japanese (and German) point of view, fuel consumption was a big deal, again a twin-engined fighter is in disadvantage

Kasei 20 series (versions without the fancy reduction gear) were 500 lbs heavier than the Ha 102, and were using bigger propellers, so installing them on the Ki 45 would've been quite a task. An 1-engined fighter with Kasei in the nose seems to me as a more realistic proposal.

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## GrauGeist (Nov 26, 2022)

Regarding the MW50, I understand that it was first used operationally on the DB605 around 1944 - not the 1930's.


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## GregP (Nov 26, 2022)

Reluctant Poster said:


> The irony of the P-47 is that the role it is most notable for is ground attack in which the turbocharger was an unnecessary expense and in fact added weight. A Corsair optimized for a land-based role would have been less expensive and in view of the much, much lower take off distance would have required less airfield preparation and without the complexity of the turbocharger maintenance would have been simpler.



I think the P-47 was, by a large margin, the overall best high-altitude fighter of the war in terms of numbers and BEING there. It was MUCH more numerous than the very few high-altitude Fw 190s and Ta152s, and could maintain sea level power up above 25,000 feet, which is WHY the P-47's high-altitude performance was so good. Late version (P-47N) were very fast up high and were going to be major trouble for anything they encountered up there, including Me 262s since they weren't too good up high and had low service ceilings relative to the P-47. The fact that P-47s had great armament and were pretty good at ground attack was an added bonus to being one of the best of not THE best high-altitude fighter produced in decent numbers. Where they weren't quite so good was up in the 15,000 to 20,000 foot range.

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## AerialTorpedoDude69 (Nov 26, 2022)

tomo pauk said:


> Do you have some good source about the Japanese modding the 601A with MW 50 in the 30s?.


I'm pretty sure you know it better than I do. I think it was Japanese Secret Projects I, Francillion's book, the section on the Ki-78 Ken. The project began in the thirties at Tokyo University before being taken over by the military and scrapped in 1944 IIRC.


tomo pauk said:


> Kasei 20 series (versions without the fancy reduction gear) were 500 lbs heavier than the Ha 102, and were using bigger propellers, so installing them on the Ki 45 would've been quite a task. An 1-engined fighter with Kasei in the nose seems to me as a more realistic proposal.


The Ki-83, heavy fighter, used the 18-cylinder version of the Kasei. But it never went beyond prototype. They should have been building these kinds of fighters much earlier but only did so toward the end of the war. I think it used the Ha 214 Ru, which I think is the turbo version of the Ha-104, but I'm not sure. They look almost identical although there's a cooling fan on the Ha-214 Ru for some reason.

(EDIT) I forgot that the Ki-63 used the Zuisei and not the Kinsei. Thanks for the correction. Had it used the Kinsei, they would have had a Ki-100 in 1942.
(EDIT2) Getting back to what you mentioned about the Ki-61 having better range, Susumu Kajinami mentioned that the rear fuselage tank on the Ki-61 was removed in the field to prevent it from exploding, particularly when shot from behind. This mod reduced the Ki-61's range but provided a lot more safety (he claimed this mod saved his life). I don't know what the actual range was, but with that tank removed, it was likely similar in range to a BF-109, which had worse range than a Ki-44.


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## tomo pauk (Nov 27, 2022)

AerialTorpedoDude69 said:


> I'm pretty sure you know it better than I do. I think it was Japanese Secret Projects I, Francillion's book, the section on the Ki-78 Ken. The project began in the thirties at Tokyo University before being taken over by the military and scrapped in 1944 IIRC.


_Now _I know about that, thank you for the tip 
It was certainly shortsighted from the IJA not pushing for an earlier and wider proliferation of water-alcohol systems in the in-service engines once they were aware of the good results. Not just on the V12 engines, but also on radials, since the radials were in much greater supply and use; the 1st two Ha-40 seem to be delivered in March of 1942, and the whole 1942 saw only 61 Ha-40 produced (for comparison, just Kawasaki produced 1112 Ha-25 engines and 199 Ha-115 engines in 1942).



AerialTorpedoDude69 said:


> The Ki-83, heavy fighter, used the 18-cylinder version of the Kasei. But it never went beyond prototype. They should have been building these kinds of fighters much earlier but only did so toward the end of the war. I think it used the Ha 214 Ru, which I think is the turbo version of the Ha-104, but I'm not sure. They look almost identical although there's a cooling fan on the Ha-214 Ru for some reason.



Think that we can agree that Ki-83 was a whole new ball game when compared with Ki-45 
Japanese/Mitsubishi can build any quantity of airframes they want, unless they also have the engine to power them, these airframes will be collecting the dust in front of factory - the Ha-43 was manufactured in meager numbers, and Japanese were not exactly shelling out the turbochargers like GE did across Pacific.
Nobody prevented Japanese from making, in good quantities, an 1-engined fighter around the Ha-42 - an 18 cylinder engine that was in a far greater supply.







AerialTorpedoDude69 said:


> (EDIT) I forgot that the Ki-63 used the Zuisei and not the Kinsei. Thanks for the correction. Had it used the Kinsei, they would have had a Ki-100 in 1942.



Bingo.



AerialTorpedoDude69 said:


> (EDIT2) Getting back to what you mentioned about the Ki-61 having better range, Susumu Kajinami mentioned that the rear fuselage tank on the Ki-61 was removed in the field to prevent it from exploding, particularly when shot from behind. This mod reduced the Ki-61's range but provided a lot more safety (he claimed this mod saved his life). I don't know what the actual range was, but with that tank removed, it was likely similar in range to a BF-109, which had worse range than a Ki-44.



Yanking out the rear tank was certainly a way to reduce a range of an aircraft 
A good feedback with company might've probably seen the introduction of cooled exhaust gasses being routed to the tank (like on the La-5 for the wing tanks), CO2 purge as on the early F4Us, or perhaps installation of a smaller tank that is also better protected, or a combination?
I don't think that even with a fuselage tank removed the Ki-61 would've had a shorter range then the Ki-44, the later was outfitted with just 128 US gals + 2x35 US gal drop tanks, while the Ki-61 arried 2x50 US gal drop tanks (200 L types), and started with 199 US gals with the rear tank.
(just why the Ki-44 used 35 US gal drop tanks is a mystery to me  that aircraft was too good to pass for the IJA, yet they somehow missed the possibilities there)

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## AerialTorpedoDude69 (Nov 27, 2022)

tomo pauk said:


> Think that we can agree that Ki-83 was a whole new ball game when compared with Ki-45
> Japanese/Mitsubishi can build any quantity of airframes they want, unless they also have the engine to power them, these airframes will be collecting the dust in front of factory - the Ha-43 was manufactured in meager numbers, and Japanese were not exactly shelling out the turbochargers like GE did across Pacific.
> Nobody prevented Japanese from making, in good quantities, an 1-engined fighter around the Ha-42 - an 18 cylinder engine that was in a far greater supply.


Yes, you are right!  The Ki-83 also required a lot of wind tunnel testing because the newly formed Rikugun had to study the aerodynamics of high horsepower engines on a twin.

I do not understand why the Ha-214 or Ha-104 weren't used on a single engine aircraft. It may have been because the Japanese strategic planners subscribed to the belief that certain engines were more feasible for use on bombers rather than on fighters. And as a result, fighters like the Ki-83 hadn't had sufficient amounts of development in 1942, when the Ha-104/214 were available. NASM stated that production of the Ha-214 began in 1940 but my guess is that's an error or it refers to when development began. Or it refers to the Ha-104, which seems to have been the base model, but IDK.

But there is some evidence here that Japanese war planners were heavily influenced by fears of supply interruption by the Allies because they consistently show preference for smaller engines over larger ones. Low weight and cost doesn't consistently dominate their thinking but it has a strong influence on it.


tomo pauk said:


> 61 arried 2x50 US gal drop tanks (200 L types), and started with 199 US gals with the rear tank.
> (just why the Ki-44 used 35 US gal drop tanks is a mystery to me  that aircraft was too good to pass for the IJA, yet they somehow missed the possibilities there)


That is a good observation and I do not know. The numerous design variants of the Ki-61 also complicates this picture. From what I can tell, the Ki-61-Ia (ko) would have had a 550 liter fuel capacity with the rear fuselage tank removed. Which would mean it had a 150 liter advantage over the 109, plus large drop tanks. So you are, again, right that it would have had a longer default range. But then on top of that, the Ki-61 had better streamlining compared to the 44. 

Even with the rear fuel tank removed, it probably had several hundred miles longer range. So was it range that influenced Japanese war planners? I think it was likely both performance and range considerations.

Regarding, the Ki-44's tiny drop tanks, test pilots had complained about the Ki-44's high landing speed (and probably a high takeoff speed as well). So you can imagine that any added weight and increase in frontal drag would have had additional adverse effect on takeoff. Throughout the war, JAAF advanced airbases had very poor runways in New Guinea. My guess is that larger tanks would have adversely impacted take-off runs to the point where they couldn't function in New Guinea or on any forward airbase which might explain why only the Ki-61, Ki-45, and Ki-43 were used in that theater whereas the Ki-44 only flew from China and probably northern Japan which had better airfields. But I have no evidence on this. 

Also, from what I've read, when the Ki-61 was trialed against the Ki-44, it was tested against the Ki-44-I with a 1,200 HP engine, not the Ki-44-II. There is a good chance that when the IJA made the strategic decision to not use the Ki-44 in New Guinea, it was based on the 1,200HP version of the Ki-44, which was pretty much outperformed by the Ki-61. And then when field conditions in New Guinea showed serious defects in the Ki-61, the Ki-44-II had already been committed to air groups that weren't concerned with long range missions. A Ki-44 with slightly more development effort, such as provision for larger drop tanks, MW50, thrust stacks, and better designed wings would have been a tough competitor in New Guinea. But low-turbulence airfoils are difficult to use on short runways such as those found in New Guinea and other roughly hewn landing strips. 

I've got to imagine that part of the reason the J2M wasn't used on many forward IJN airbases outside of Guam might have had to do with its high landing speed and long takeoff run and the poor state of forward Japanese airbases. However, US test pilots had a different take on the J2M, so I might be wrong about this. Even so, as you say, cost, weight, and other infrastructure and supply factors may have taken a backseat to other concerns.

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## EwenS (Nov 27, 2022)

The first J2Ms went to the 602nd Hikotai of the 381st Kokutai to provide air defence for the Balikpapan oilfields around the end of 1943. The first air raid on Balikpapan by Australia based B-24s had taken place in Aug 1943 (the Shady Lady raid Shady Lady (aircraft) - Wikipedia). By Feb 1944 they had 10 on strength but little hope of getting more.

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## tomo pauk (Nov 28, 2022)

AerialTorpedoDude69 said:


> I do not understand why the Ha-214 or Ha-104 weren't used on a single engine aircraft. It may have been because the Japanese strategic planners subscribed to the belief that certain engines were more feasible for use on bombers rather than on fighters.



The Ha-104 was almost as good as the 2-stage versions of the R-2800 B series, without the added complexity, drag and required volume for intercoolers. It was also lighter, 2080 lb vs. 2480 lb. The R-2800 was at 52.5 in diameter, vs. 54 in for the Ha-104.
Ha-42 familiy was one of rare late-war Japanese engine designs still running okay with 87 oct fuel, this should've rated it very highly by the Japanese planers. Granted, Mitsubishi was not making the Ha 42 in really great quantities.

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## Passenger_57 (Dec 13, 2022)

Wow, I had to look up the Metroliner. Why haven’t they been grounded; that is a lot of crashes. Very TU-104esque.


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## Passenger_57 (Dec 13, 2022)

GregP said:


> One place the Japanese had a lead was aerial torpedoes. Of course, almost the entire world had better torpedoes than we did when WWII started.
> 
> The Japanese were able to design an aerial unit that could be dropped into Pearl Harbor without hitting the bottom of the harbor. At the time, U.S. torpedoes were not very good and were never able to be dropped in quite as shallow water.


Those very successful torpedos were also a real threat to the ship as they were filled with oxygen and required extra oxygen storage. The explosives in their warheads were also much more susceptible to being detonated by shock. At least one IJN cruiser was lost when it torpedo tubes were struck.

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## AerialTorpedoDude69 (Dec 13, 2022)

Passenger_57 said:


> Those very successful torpedos were also a real threat to the ship as they were filled with oxygen and required extra oxygen storage. The explosives in their warheads were also much more susceptible to being detonated by shock. At least one IJN cruiser was lost when it torpedo tubes were struck.


This is a misconception. The Japanese used a world-class torpedo, of conventional design, as its standard aerial torpedo, during World War II. The oxygen-propelled torpedo (of which there were several variations) was a radically different technology than what was used in conventional designs of that era. And it was not loaded onboard carriers (at least as a munition for a torpedo bomber). There's a good reason for that: You would not want an oxygen-fueled torpedo anywhere near a combustion engine.

There was a plan to create an oxygen-propelled aerial torpedo, but these things were huge and only Japan's four-engine flying boats could carry them. Of course, these plans were scapped because you just couldn't risk putting such a volatile system near a combustion engine. And they were absolutely gigantic, which is why their range was off the charts.

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## GrauGeist (Dec 13, 2022)

Yes, the Type 93 (Long Lance) torpedoes were indeed large: 6,000 pounds and 31.5 feet long.

Which is a bit large to be carried by an aircraft.

As an aside, the Type 93 was large enough, that with some modifications it became a series of manned (suicide) torpedo.

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## cherry blossom (Dec 13, 2022)

tomo pauk said:


> The Ha-104 was almost as good as the 2-stage versions of the R-2800 B series, without the added complexity, drag and required volume for intercoolers. It was also lighter, 2080 lb vs. 2480 lb. The R-2800 was at 52.5 in diameter, vs. 54 in for the Ha-104.
> Ha-42 familiy was one of rare late-war Japanese engine designs still running okay with 87 oct fuel, this should've rated it very highly by the Japanese planers. Granted, Mitsubishi was not making the Ha 42 in really great quantities.


I agree that the Ha 104/Ha 42-11 was a reliable engine that might have seen more use but the dry weight that I have is 1140 kg or 2513 lb. Mitsubishi seems to have achieved reliability by running a fairly heavy engine with a large swept volume at relatively low revs giving 1900ps at 2450 rpm for takeoff and 1810ps at 2200m at 2400 rpm or 1610ps at 6100m at 2400 rpm.

There was a redesigned version called the 18E by Mitsubishi and Ha 42-21 or Ha 214 by the Army (MK10 by the Navy), which was heavier at 1235 kg or 2723 lb. Only photographs of those survive (from the crashed Ki-93 prototype when the rear cowling panel came away) but Goodwin and Starkings argue that Mitsubishi used the ideas from the Ha-43/MK9 such as driving the valves from two cam-rings rather than from the front as in the Kasei and Ha 104. That is said to have given 2500ps at 2600 rpm for takeoff and 2300ps at 2000 m and 2500 rpm or 2000ps at 6500 m and 2500 rpm. However, the Wikipedia article on the Ki-93 Rikugun Ki-93 - Wikipedia states that only 1970 ps was actually available.

Both the Ha-43/MK9 and especially the Homare were lighter (980 kg or 2160 lb and only 830 kg or 1830 lb).

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## tomo pauk (Dec 13, 2022)

cherry blossom said:


> I agree that the Ha 104/Ha 42-11 was a reliable engine that might have seen more use but the dry weight that I have is 1140 kg or 2513 lb. Mitsubishi seems to have achieved reliability by running a fairly heavy engine with a large swept volume at relatively low revs giving 1900ps at 2450 rpm for takeoff and 1810ps at 2200m at 2400 rpm or 1610ps at 6100m at 2400 rpm.



The 2080 lb is the figure from the big TAIC manual. The Ki-67-specific TAIC report notes the weight of the engines as 2190 lbs (994 kg; it also mentions the water injection jets FWIW). The Bunrin Do book about the Ki-67 says 946 kg (2086 lbs).

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## cherry blossom (Dec 13, 2022)

Those sound convincing sources. I was following Goodwin and Starking page 120 and a website q‹ó‹@ƒGƒ“ƒWƒ“ˆê——E“ú–{ŒR with the same weights. I am slightly distrustful of the website as it gives the same weight for the turbo version. Just possibly the higher weights include a turbosupercharger and associated piping.

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## cherry blossom (Dec 16, 2022)

I have just seen the helpful post Which Japanese fighter had dual-stage superchargers? with its link to Mitsubishi Ha 42 Model 41 Ru (Ha 214 Ru), Radial 18 Engine. That site says "Approximate (Weight on Stand): 1551.3kg (3420lb.)" for the Ha 214 with its turbosupercharger but without "Missing starter, generator, carburetor, spark plugs and data plate". Thus we have a moderately complete Ha 214, the photographs show that it does have two cam-rings and it is quite heavy.

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