# Why the early war Japanese fighters were structurally fragile and unarmored?



## Jenisch (Apr 17, 2012)

Hello,

I'm wondering if the Japanese accepted such disadvantages to have more range or agility. I think it was because both, because they were interconnected. And the main reason apparently was the lack of more powerful engines, at least in the Zero, as Jiro Horikoshi tells this in his book of the creation of the Zero.


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## davebender (Apr 17, 2012)

I don't think Japanese aircraft were structurally fragile. They just lacked armor.


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## Jenisch (Apr 17, 2012)

davebender said:


> I don't think Japanese aircraft were structurally fragile. They just lacked armor.


 
The early war Japanese planes certainly were. They could not follow Allied types such as the P-40 in a dive.


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## Juha (Apr 17, 2012)

And they found out rapidly that Ki-43 needed some structural strenghtening.

Juha


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## Messy1 (Apr 17, 2012)

Starting out early in the war, the Japanese planes were not as robustly built as many allied planes.


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## tyrodtom (Apr 17, 2012)

In comparision with western opponents, they were fragile, or not as overbuilt. Especially the Oscar, according to a interview on U-Tube with a WW2 Oscar pilot, you had to be careful in manuvers, and it shook at high speed.
A A6M2's never exceed speed was below 400mph, with no armor, no self sealing tanks, and not overbuilt, if not fragile. Self-sealing tanks are heavier, and take up possible fuel volumn. They took every measure possible to give maximum range, manuver, and speed, with the limited engine power they had. Everything worked fine as long as they were on the offensive. But if any aircraft could bring it's guns to bear on a Zero, or Oscar, they were in deep trouble, because they could absorb no damage, with no protection, and no excess strength. Their extreme manuverabilty at low speeds made it hard for their opponents to ever get a gunsight on them, but when we learned not to try to fight them at their best speed, but at ours, it was over quick.


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## davebender (Apr 17, 2012)

Be careful here. Many U.S. built fighter aircraft were rather heavy compared to contemporary fighter aircraft. A flying brick is very robust but you pay a price in aerial performance.


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## Vincenzo (Apr 17, 2012)

someone posted data on Zero that was not structurally fragile. i hope some can remember where is that engineering analysis


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## FLYBOYJ (Apr 17, 2012)

I believe you're looking at these aircraft being capable of taking +6/ -3 Gs. Unless they were starting to fall about from being over stressed, they were not structurally fragile unless they had a volley of .50 calibers pumped into them.


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## tyrodtom (Apr 17, 2012)

I remember reading in Pappy Boyington's book, that most of the Japanese pilots he encountered flew beautifully co-ordinated manuvers, never out of trim. Where he would delibertly fly out of trim, to throw the enemy's aim off, his aircraft would actually be going in a little different direction than what it appeared.

I'm just going by one pilots interview, but according to him, the Oscar might have been a little fragile, and in it's case in trim flight might have been necessary, because it's less stressful on the structure.

And I know when trying to get the best performance from a aircraft, in trim flight is required to get the best.


I'm not saying the Zero, or other Japanese aircraft were fragile, except, maybe the Oscar. But a fighter aircraft at some time in it's service is going to take damage, most Japanese fighters and bombers would not absorb much gunfire, they torched or fell apart.


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## FLYBOYJ (Apr 17, 2012)

tyrodtom said:


> I remember reading in Pappy Boyington's book, that most of the Japanese pilots he encountered flew beautifully co-ordinated manuvers, never out of trim. Where he would delibertly fly out of trim, to throw the enemy's aim off, his aircraft would actually be going in a little different direction than what it appeared.
> 
> And I know when trying to get the best performance from a aircraft, in trim flight is required to get the best.



Actually you want a fighter to have a degree of instability built into it and I guess this reflects the point.


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## tyrodtom (Apr 17, 2012)

I guess trim was a bad choice of words. What Pappy meant was he was flying in a skid or slip sometimes, and deliberately didn't have the ball centered in turns. Just to make the other guys aiming problems just a little more difficult.

I've read of a similiar approach from another WW2 fighter pilot also, but can't recall who.

What Pappy said for example, they were perfect loops, round, and you could likely guess where the loop wound end. It made it easier to lead them with your fire.

From the interview with the Oscar pilot, it sounded like it had to be flown that way, it wouldn't hold up under rough handling.


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## FLYBOYJ (Apr 17, 2012)

tyrodtom said:


> I guess trim was a bad choice of words. What Pappy meant was he was flying in a skid or slip sometimes, and deliberately didn't have the ball centered in turns. Just to make the other guys aiming problems just a little more difficult.
> 
> I've read of a similiar approach from another WW2 fighter pilot also, but can't recall who.



Actually you never fly a fighter coordinated, as you quoted Boyington, you always want to be uncoordinated to a point for the reasons stated. But the other point, you don't want a fighter to be too stable.


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## tomo pauk (Apr 17, 2012)

Vincenzo said:


> someone posted data on Zero that was not structurally fragile. i hope some can remember where is that engineering analysis



Maybe this one?


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## drgondog (Apr 17, 2012)

One advanced feature for the time was extruded wing spars, even with the splice. More expensive than beam cap/shear web as mostly followed in late 1930-1940 designs - but lighter due to absense of more rivets.

I don't know what the Japanese design structural standards were but suspect no less than preliminary design/prototype 8g limit positive/-3g limit negative. Remember the 51 was an 8g a/c at 8000 pounds and actual limit load capability shrunk to ~ 6.4 g at 10,000 punds gross weight for the D, and less at max Gross Wt.


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## Jenisch (Apr 17, 2012)

Mitsubishi A6M Zero - Wikipedia, the free encyclopedia:

Captain Eric Brown, the Chief Naval Test Pilot of the Royal Navy, recalled being impressed by the Zero during tests of captured aircraft. "I don’t think I have ever flown a fighter that could match the rate of turn of the Zero. The Zero had ruled the roost totally and was the finest fighter in the world until mid-1943."


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## FLYBOYJ (Apr 17, 2012)

Jenisch said:


> Mitsubishi A6M Zero - Wikipedia, the free encyclopedia:
> 
> Captain Eric Brown, the Chief Naval Test Pilot of the Royal Navy, recalled being impressed by the Zero during tests of captured aircraft. "I don’t think I have ever flown a fighter that could match the rate of turn of the Zero. The Zero had ruled the roost totally and was the finest fighter in the world until mid-1943."


Doesn't mention at what speed....


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## Vincenzo (Apr 17, 2012)

tomo pauk said:


> Maybe this one?



yes i've read the web version Design Analysis of the Zeke 32 (Hamp - Mitsubishi A6M3)


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## fastmongrel (Apr 18, 2012)

tyrodtom said:


> I remember reading in Pappy Boyington's book, that most of the Japanese pilots he encountered flew beautifully co-ordinated manuvers, never out of trim. Where he would delibertly fly out of trim, to throw the enemy's aim off, his aircraft would actually be going in a little different direction than what it appeared.
> 
> .



Seems to have been a common trick in one book I have read an experienced BOB pilot said you could always tell the new guys because they flew straight and stiff. The guys who had a few sorties under there belts soon learnt to play with the trim and just accept the fact that you couldnt fly hands and feet off.


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## ColesAircraft (Apr 18, 2012)

I think it may be said that the design and manufacturing philosophy employed by Japan in the '30s and '40s has extended to their modern automobile industry: an emphasis on light weight and efficiency, which in the case of automobiles has made Japan what it is today thanks to oil prices. 

I don't think it's fair to say that this philosophy was imposed upon Japan due to an inability of Japanese industry to manufacture powerful aircraft engines. The Nakajima Sakae that powered the Zero possessed an impressive power to weight ratio (much as their modern automotive counterparts do). In fact when restorers of Zeros today replace the Sakae with the best American-made replacement engines they can find, the performance of the aircraft suffers dramatically. There is simply no non-Japanese radial engine in the world capable of replacing the original - anywhere, by any manufacturer or nation.

The Japanese adopted this philosophy in large part as the aviation industries of the world debated the value of light versus heavy fighters (and the British built the Defiant, unfortunately). It was certainly a natural choice for Japan to go the light fighter route for economic reasons, but that wasn't the only factor. The US experimented with light fighters as well, and the idea was behind the original Bf109 in Germany. Unlike the 109, however, the Zero was less able to adapt itself to more powerful engines and heavier equipment as the need for such measures became apparent. But for many months of the war the Zero ruled the Pacific.

The designers of the Zero also created the Raiden (or "Jack"), which was a heavy fighter/interceptor in every respect with impressive performance comparable to Allied designs. Ironically, most Japanese pilots disliked it immensely (Saburo Sakai saying "it flew like a truck"). The Japanese could do it, and do it well. But after 1942 their cause was lost. 

Ron Cole









Cole's Aircraft Website:index


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## FLYBOYJ (Apr 19, 2012)

ColesAircraft said:


> I think it may be said that the design and manufacturing philosophy employed by Japan in the '30s and '40s has extended to their modern automobile industry: an emphasis on light weight and efficiency, which in the case of automobiles has made Japan what it is today thanks to oil prices.
> 
> I don't think it's fair to say that this philosophy was imposed upon Japan due to an inability of Japanese industry to manufacture powerful aircraft engines. The Nakajima Sakae that powered the Zero possessed an impressive power to weight ratio (much as their modern automotive counterparts do). *In fact when restorers of Zeros today replace the Sakae with the best American-made replacement engines they can find, the performance of the aircraft suffers dramatically. There is simply no non-Japanese radial engine in the world capable of replacing the original - anywhere, by any manufacturer or nation.*The Japanese adopted this philosophy in large part as the aviation industries of the world debated the value of light versus heavy fighters (and the British built the Defiant, unfortunately). It was certainly a natural choice for Japan to go the light fighter route for economic reasons, but that wasn't the only factor. The US experimented with light fighters as well, and the idea was behind the original Bf109 in Germany. Unlike the 109, however, the Zero was less able to adapt itself to more powerful engines and heavier equipment as the need for such measures became apparent. But for many months of the war the Zero ruled the Pacific.
> 
> ...



I believe only one restored Zero currently flies wth a US engine (R1830) and it's loacted at the CAF chapter in Camarillo, CA. I have met some of the pilots who have flown this aircraft and one of our mods on this site is a member of this CAF chapter. Never have I heard "the performance of the aircraft suffers dramatically, " so please if you have information on this, I'm all ears. Additionally I hope Eric sees this and maybe can chime in as we can hear "direct from the source."

Here's some basic info comparing the two engines...

Specifications (Sakae 21)
General characteristicsType: 14-cylinder air-cooled two-row radial engine
Bore: 130 mm (5.1 in)
Stroke: 150 mm (5.9 in)
Displacement: 27.8 L (1,700 in³)
Length: 1,600 mm (63 in)
Diameter: 1,144 mm (45.0 in)
Dry weight: 533 kg (1,180 lb)
ComponentsValvetrain: Overhead valve
Supercharger: Gear driven, two speed.
Fuel system: Nakajima twin choke carburettor, automatic mixture and boost control.
Cooling system: Air-cooled
PerformancePower output: 761 kW (1,020 hp) at 2,600 rpm at 6,400 ft (1,950 m)
Specific power: 30.2 kW/L (0.66 hp/in³)
Compression ratio: 7:1
Power-to-weight ratio: 1.43 kW/kg (0.87 hp/lb)

Specifications (R-1830-S1C-G) 
Pratt Whitney R-1830 "Twin Wasp" (sectioned)Data from [2]

General characteristicsType: Fourteen-cylinder two-row supercharged air-cooled radial engine
Bore: 5.5 in (139.7 mm)
Stroke: 5.5 in (139.7 mm)
Displacement: 1,829.4 in³ (30 l)
Length: 59.06 in (1,500 mm)
Diameter: 48.03 in (1,220 mm)
Dry weight: 1,250 lb (567 kg)
ComponentsValvetrain: Two overhead valves per cylinder
Supercharger: Single-speed General Electric centrifugal type supercharger, 7.15:1 reduction
Fuel system: Two-barrel Stromberg carburetor
Fuel type: 95-100 octane rating gasoline
Cooling system: Air-cooled
Reduction gear: Epicyclic gearing, 2:3
PerformancePower output:

1,200 hp (895 kW) at 2,700 rpm for takeoff
700 hp (522 kW) at 2,325 rpm cruise power at 13,120 ft (4,000 m)
Specific power: 0.66 hp/in³ (29.83 kW/l)
Compression ratio: 6.7:1
Specific fuel consumption: 0.49 lb/(hp•h) (295 g/(kW•h))
Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg)


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## evangilder (Apr 19, 2012)

ColesAircraft said:


> The Nakajima Sakae that powered the Zero possessed an impressive power to weight ratio (much as their modern automotive counterparts do). In fact when restorers of Zeros today replace the Sakae with the best American-made replacement engines they can find, *the performance of the aircraft suffers dramatically.* There is simply no non-Japanese radial engine in the world capable of replacing the original - anywhere, by any manufacturer or nation.



Uh, no. I have personally witness 3 authentic Zeros fly, one with a Sakae and 2 without. There is a slight difference in the sound, but other than that, the aircraft performs pretty much the same. Aside from that, the Sakae 21 was truly a "Japanese" engine. The Sakae was pretty much a license built Gnome-Rhone 14K. 

With any aircraft, there is a ratio of weight to power that will effect things like maneuverability and range. The Zero was built for range, and that it had. Below 250 MPH, nothing could out-turn it. Above that speed, the ailerons "turn to concrete", according to one of the pilots I know who has flown the Zero. Most allied pilot learned (sometime the hard way) that a slow speed turning flight with a Zero was not winnable. 

There was one piece of armor in the Zero, believe it or not. It's about the size of a basketball in size and sits just behine the pilot in about the small of the back. Not a whole lot of help. The main windscreen is also very light. But if you put armor, self-sealing fuel tanks and a bullet resistant canopy on it, the weight increases, which causes performance and range to suffer. It's always a trade-off, and for the early years of the war, it worked well for the Japanese.


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## Vincenzo (Apr 19, 2012)

i think that is a old mith that Sakae was a GR-14K.
the data of power for Sakae 21 were 1100 HP at 2700 rpm t +200 boost (nominal power ) at 2.850 meters, and 980 hp at 6.000 meters (1130 HP at TO with TO setting (2750 rpm +300 boost)
Twin Wasp S1C-G get 1200 HP to TO and only 1050 HP at nominal at 6.500 feet so is inferior in large parte of altitude and this is with 100 octane fuel, early Twin Wasp with 87 octane fuel get only 900 HP nominal (commonly at relatively low altitude). If you has a R-1830-76 of navy this get nearly same power of Sakae-21 at high altitude (ever with 100 octane fuel) but is larger and heavier (~200 kilos)


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## tomo pauk (Apr 19, 2012)

ColesAircraft said:


> I think it may be said that the design and manufacturing philosophy employed by Japan in the '30s and '40s has extended to their modern automobile industry: an emphasis on light weight and efficiency, *which in the case of automobiles has made Japan what it is today thanks to oil prices.*
> 
> ...



What makes Japanese cars so great (and S. Korean, of course) is their utter reliability. 
Italian and French manufacturers make many different low-consumption cars (just Fiat makes 4 models (more maybe?), from Grande Punto down), but those are strong only in the domestic markets. The British also had many low-consumption stuff, but their auto industry is in shambles for quite a while.


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## FLYBOYJ (Apr 19, 2012)

Vincenzo said:


> i think that is a old mith that Sakae was a GR-14K.
> the data of power for Sakae 21 were 1100 HP at 2700 rpm t +200 boost (nominal power ) at 2.850 meters, and 980 hp at 6.000 meters (1130 HP at TO with TO setting (2750 rpm +300 boost)
> Twin Wasp S1C-G get 1200 HP to TO and only 1050 HP at nominal at 6.500 feet so is inferior in large parte of altitude and this is with 100 octane fuel, early Twin Wasp with 87 octane fuel get only 900 HP nominal (commonly at relatively low altitude). If you has a R-1830-76 of navy this get nearly same power of Sakae-21 at high altitude (ever with 100 octane fuel) but is larger and heavier (~200 kilos)


Even with this, there is no documented proof that I'm aware of that the restored CAF Zero flying with the R1830 installed has _*"the performance of the aircraft suffer dramatically"*_ even with the increased weight.


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## Vincenzo (Apr 19, 2012)

Is not a documented proof but with a heavier, larger and less powerfull engine is highly probable that the performance suffer, maybe not dramatically


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## FLYBOYJ (Apr 19, 2012)

Vincenzo said:


> Is not a documented proof but with a heavier, larger and less powerfull engine is highly probable that the performance suffer, maybe not dramatically


Not really. A lot of equipment is removed from these aircraft during restoration, a big factor are the guns and radios, although I know many japanese aircraft did not have radios installed. I've been around several guys who have flown both the Camarillo and Chino Zero (the later has the Sakae engine)and never heard of any reports of the P&W Zero dramitically affected by the intallation of that engine. Keep in mind that both aircraft are not flown hard and are very well maintained from what I have seen.

Even with a larger and less powerful engine one has to look at the overall weight of the aircraft, the prop engine combination and the way its rigged. Mind you this dicussion centers around restored aircraft being operated in "today's" world.


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## Vincenzo (Apr 19, 2012)

i can agree that flying them how they flying today the difference maybe negligible


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## ColesAircraft (Apr 19, 2012)

evangilder said:


> Uh, no. I have personally witness 3 authentic Zeros fly, one with a Sakae and 2 without. There is a slight difference in the sound, but other than that, the aircraft performs pretty much the same. Aside from that, the Sakae 21 was truly a "Japanese" engine. The Sakae was pretty much a license built Gnome-Rhone 14K.
> 
> With any aircraft, there is a ratio of weight to power that will effect things like maneuverability and range. The Zero was built for range, and that it had. Below 250 MPH, nothing could out-turn it. Above that speed, the ailerons "turn to concrete", according to one of the pilots I know who has flown the Zero. Most allied pilot learned (sometime the hard way) that a slow speed turning flight with a Zero was not winnable.
> 
> There was one piece of armor in the Zero, believe it or not. It's about the size of a basketball in size and sits just behine the pilot in about the small of the back. Not a whole lot of help. The main windscreen is also very light. But if you put armor, self-sealing fuel tanks and a bullet resistant canopy on it, the weight increases, which causes performance and range to suffer. It's always a trade-off, and for the early years of the war, it worked well for the Japanese.




That's kind of a bizarre statement. In the first place none of these aircraft are pushed to their limits during airshow displays - especially the Chino Zero which is the only originally-powered Zero in the world and is flown very cautiously, as it should be. Secondly, how can anyone judge and compare performances of aircraft from the vantage point of the ground???

And, indeed, the myth that the Nakajima Sakae was a copy of any other engine originated in the bigoted environment of wartime when whites couldn't conceive that the Japanese were capable of independent ingenuity.

I didn't post my information to start an argument. Just thought I'd share what I know, since the question was posed. My friend Naburo Harada, who owns several restored Zeros in Japan and oversees the Harada Collection (The Harada Collection), knows more than anyone on earth about this engine, the power to weight issue, and the consequences of not using the original Sakae.

Ron Cole


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## FLYBOYJ (Apr 19, 2012)

ColesAircraft said:


> That's kind of a bizarre statement. In the first place none of these aircraft are pushed to their limits during airshow displays - especially the Chino Zero which is the only originally-powered Zero in the world and is flown very cautiously, as it should be. Secondly, how can anyone judge and compare performances of aircraft from the vantage point of the ground???


Then how can one say the P&W Zero's performance "suffered dramatically" by the intallation of that engine? Neither aircraft are pushed to their limits during routine flight and airshows. BTW, my query is based on comments by the pilots who have flown them, not from a ground vantage point.


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## Jenisch (Apr 19, 2012)

ColesAircraft said:


> The Japanese adopted this philosophy in large part as the aviation industries of the world debated the value of light versus heavy fighters (and the British built the Defiant, unfortunately).



That was not the desire of Jiro Horikoshi with the Zero. He states in Eagles of Mitubishi: the story of the Zero figher, that lack of more powerful engines not allowed the add of armor and structural strenght and keep up with the requeriments. 

As for the Ki-43:


_View: https://www.youtube.com/watch?v=u-eBmnpCO18_

23s: "They tried too much to increase its range, and so made it fragile". Similar aircraft, similar problem, probably similar engineering challange than the Zero. 

Conclusion: if the Japanese didn't have the long range requirement, we probably would see them with aircraft similar to the P-40 and Bf 109.


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## FLYBOYJ (Apr 19, 2012)

Steve Hinton going through the Chino Zero's cockpit


_View: https://www.youtube.com/watch?v=R6W9MBK1gJI_


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## FLYBOYJ (Apr 19, 2012)

_View: https://www.youtube.com/watch?v=UmUseKNrh6Q_

I think Eric, knows this guy. Says nothing about this aircraft's "airshow" performance being affected by the instllation of the 1830.


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## ColesAircraft (Apr 19, 2012)

Jenisch said:


> That was not the desire of Jiro Horikoshi with the Zero. He states in Eagles of Mitubishi: the story of the Zero figher, that lack of more powerful engines not allowed the add of armor and structural strenght and keep up with the requeriments.
> 
> As for the Ki-43:
> 
> ...





Great video, but wrong conclusion.

Japanese Army fighters had few Army-specified range requirements as a rule. The reason for that was simple: they were designed to fight a continental war in China or Russia where range was not as critical an issue as it was in the Pacific. This made Army fighters, including the "Oscar", of little use in many Pacific campaigns. Remember that the Japanese Army and Navy were to an extent at cross purposes before the war - the Army equipped itself to fight Russia, while the Navy did likewise to fight America; very different enemies! That's why the Army Air Force played no role in the Guadalcanal battles while the Navy had to overextend its deployed G4Ms and A6Ms. They were the only aircraft that could get there and home. In fact the "Oscar" was an even better example of the Japanese 'light fighter' mentality that I mentioned earlier, as range was less an issue in its design than it was for the Zero. Saburo Sakai mentioned this situation to me when I knew him. The Navy pilots resented that the Army planners hadn't placed more emphasis on range, which left the Navy to fight alone in many circumstances. 

The closest thing to a heavy fighter that the Army ever produced in quantity was the Ki-44 (the Ki-84 being more a compromise, I think). Again, an example of a good, powerful Japanese engine bolted to an aircraft of good performance. They served the Japanese well in China but were dogged with limited range in the Pacific, where they were seldom even deployed. By the time they were used as interceptors in home defense the type was obsolete and overwhelmed. But a good aircraft it still was, and again shows that the Japanese could do the 'heavy' thing when they wanted to. 

The Japanese would have built P-40s??? Sakai expressed contempt for the P-40, as did most Japanese pilots who met them in combat. The Japanese Army actually operated a small unit of captured P-40s they obtained intact from the Philippines, but it was a very short lived experiment. I think it's a beautiful plane, but it wasn't an aircraft, or the embodiment of a concept, that the Japanese wanted to emulate. 

Ron Cole

Ron Cole


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## ColesAircraft (Apr 19, 2012)

FLYBOYJ said:


> Then how can one say the P&W Zero's performance "suffered dramatically" by the intallation of that engine? Neither aircraft are pushed to their limits during routine flight and airshows. BTW, my query is based on comments by the pilots who have flown them, not from a ground vantage point.



Easily, when the only person in the world who owns four Zeros says so. Granted, there may be some pro-Japanese bias on the part of the source, but I know how hard Mr. Harada fought for years to get an original Sakae for his airworthy example. It sat, otherwise completely restored, with no engine for close to half a decade. 

There may likewise be some pro-American bias in this as well on the part of some pilots. I don't know. I just thought I'd help answer the questions posed in this thread with my experience. 

The Sakae series of radials were amazing pieces of technology in terms of their weight in relation to their power output. It, and the similarly designed Mitsubishi powerplant that lost out to it in competition in 1939, were in large part responsible for the ultimate success of the Zero - so said Jiro Horikoshi. Since no other nation took the 'light fighter' concept to fruition as did the Japanese - nobody mass-produced comparable engines to the Sakae. Thus . . . today it's essentially irreplaceable and the performance of Zeros equipped with lesser (heavier) powerplants see their performance suffer. Now, it may be that the "suffered dramatically" opinion that originated with Nobuo Harada took into consideration fuel consumption - something that obviously would not play any role in an air show hop. 

But, Jeez! Now I know why I avoid posting in forums. Put this effort into debating heath care or something. 


Ron Cole


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## ColesAircraft (Apr 19, 2012)

Jenisch wrote: "That was not the desire of Jiro Horikoshi with the Zero. He states in Eagles of Mitubishi: the story of the Zero figher, that lack of more powerful engines not allowed the add of armor and structural strenght and keep up with the requeriments."


The desire of Mr. Horikoshi was to meet the Navy specifications, which called for a light fighter capable of carrier deployment, long range, and extreme maneuverability. The A4M "Claude" was built with identical priorities in mind, and both envisioned aerial opponents similar to those met in China: the Russian I-16 Ratta, for example, all primarily light fighters. His book is an excellent resource - probably the best book ever written that details the development of a WW2 fighter aircraft - but he also wrote extensively for the Japanese-language magazine Koku Fan in the 1960s and '70s, where he goes into even more detail regarding the Zero's technical development.

It is true that the engine/airframe combination that was adopted in 1939 restricted the Zero when the Navy demanded heavier armament, bomb-carrying capabilities, and armor plate. I said that in my original post, and noted how, unlike the Zero, the Bf109 was better able to adapt itself.

It's also worth noting, since we're invoking pilot perspectives, that Japanese pilots during WW2 strongly preferred the lighter and less powerful A6M2-21 to any other later variant. They were coveted by units and their best pilots as their numbers dwindled. I've never heard similar claims from Luftwaffe pilots regarding the 'Emil'. This, again, bespeaks the point of my original thesis: there was a difference in philosophy regarding design and development between Japan and the West, and it still exists today. The Zero was as much a product of that as the Honda Civic Si, both dramatically different - by intent, not so much limitations - from the F4U Corsair and the Chevy Camaro. 


Ron Cole


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## Jenisch (Apr 19, 2012)

ColesAircraft said:


> Japanese Army fighters had few Army-specified range requirements as a rule.



The Ki-43 Model 2 had 1,760 km of range, and 3,200 km of ferry range. The Ki-43 Model 1 (didn't found data for it) had more range, since it was ligther and with a less powerful engine. The data of the model 2 is probably with drop tanks, but even so the numbers clearly agree with Hinoki: there was a desire for long range in the Ki-43!



> The Japanese would have built P-40s???



God, I didn't wrote this!


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## ColesAircraft (Apr 19, 2012)

Jenisch said:


> The Ki-43 Model 2 had 1,760 km of range, and 3,200 km of ferry range. The Ki-43 Model 1 (didn't found data for it) had more range, since it was ligther and with a less powerful engine. The data of the model 2 is probably with drop tanks, but even so the numbers clearly agree with Hinoki: there was a desire for long range in the Ki-43



I wrote that range wasn't a priority for the Army - not that it was never considered. And it's not "me" versus "Hinoki". Mr. Hinoki died in 1976, so I did not get to know him. But as I've studied and written about this subject since 1984, I did get to know Sakai, Satoru Anabuki (probably the ultimate "Oscar" ace), Misajiro Kuwato, Zenji Abe, Saburo Saito and others. I founded the first dedicated organization to promote the study of Japanese WW2 aircraft, JII and the Asahi Journal, in 1987 and that eventually became J-Aircraft.com. Please . . . before you regulars just assume that the new guy must be ignorant of the subject at hand - consider that I might actually know what I'm talking about, and you could stand to learn a thing or two.

I was just trying to help. I won't bother again.


Ron Cole


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## Jenisch (Apr 19, 2012)

ColesAircraft said:


> I wrote that range wasn't a priority for the Army - not that it was never considered.



And I just posted the interview of the pilot, and data of the Ki-43, both letting clear the Ki-43 was weaker structurally because the range requirement. In the case of the Zero, a notable drop in range can be constated in the models with self-sealing fuel tanks and armor of the aircraft. 

To put the things in a better perspective: try built a WWII fighter with the range of the Ki-43 and specially the Zero, with power plants at around 1000 hp. Any designer in the world at the time would adopt the solutions the Japanese did. This is why I mentioned they would have aircraft SIMILAR to the P-40 and the Bf 109 - with self sealing tanks and armor - if they didn't have the range requeriment.



> Mr. Hinoki died in 1976, so I did not get to know him.



As far as I know, it was in 1991.



> But as I've studied and written about this subject since 1984, I did get to know Sakai, Satoru Anabuki (probably the ultimate "Oscar" ace), Misajiro Kuwato, Zenji Abe, Saburo Saito and others. I founded the first dedicated organization to promote the study of Japanese WW2 aircraft, JII and the Asahi Journal, in 1987 and that eventually became J-Aircraft.com. Please . . . before you regulars just assume that the new guy must be ignorant of the subject at hand - consider that I might actually know what I'm talking about, and you could stand to learn a thing or two.



Your personal experiences are welcomed to everyone here, but they don't have nothing to do with our discussion.



> I was just trying to help. I won't bother again.


 
You wasn't bothering, but is clearly feeling persecuted - which is not the case.


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## tyrodtom (Apr 19, 2012)

The pilot, good as he may be, didn't design the aircraft. 

The stated range you give for the Ki-43 is about half of the range of a Zero. Ferry range has nothing to do with combat radius. Combat radius on a aircraft with drop tanks is how far the aircraft can fly after it gets rid of the drop tanks and engages in however many minutes of combat, and RTB on internal fuel.

Ferry range is how far you can fly on internal fuel and drop tanks, no combat. It will be a great deal more than just twice the combat radius.


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## FLYBOYJ (Apr 19, 2012)

ColesAircraft said:


> Easily, when the only person in the world who owns four Zeros says so.


And the last time he flew one?



ColesAircraft said:


> Granted, there may be some pro-Japanese bias on the part of the source, but I know how hard Mr. Harada fought for years to get an original Sakae for his airworthy example. It sat, otherwise completely restored, with no engine for close to half a decade.


And kudos to him, but at the same time I see no substancial evidence supporting his claim about the Camarillo Zero


ColesAircraft said:


> There may likewise be some pro-American bias in this as well on the part of some pilots. I don't know. I just thought I'd help answer the questions posed in this thread with my experience.


In your experience have you ever flown any of these aircraft (or similar)?


ColesAircraft said:


> The Sakae series of radials were amazing pieces of technology in terms of their weight in relation to their power output. It, and the similarly designed Mitsubishi powerplant that lost out to it in competition in 1939, were in large part responsible for the ultimate success of the Zero - so said Jiro Horikoshi. Since no other nation took the 'light fighter' concept to fruition as did the Japanese - nobody mass-produced comparable engines to the Sakae. Thus . . . today it's essentially irreplaceable and the performance of Zeros equipped with lesser (heavier) powerplants see their performance suffer. Now, it may be that the "suffered dramatically" opinion that originated with Nobuo Harada took into consideration fuel consumption - something that obviously would not play any role in an air show hop.


Ok, I'll but that, but according to thouse who fly the Camarillo Zero, the fact that an 1830 is on the front end of the aircraft means little under 200 knots.


ColesAircraft said:


> But, Jeez! Now I know why I avoid posting in forums. Put this effort into debating heath care or something.
> 
> 
> Ron Cole


We would if this was a boaring political forum.


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## GregP (Apr 19, 2012)

As far as we know at the Planes of Fame, there are reasons for the Japanese approach. When we restored our A6M5 Model 52 Zero, with the original engine, we had the help of the original designer, Jiro Horikoshi. Accoring to him, the Japanese Military was interested in the absolute most maneuverable monoplane fighter in the world. They were working on a larger more powerful radial, but didn't have it yet.

So, he set out to use the radial avaiable. In order to get the required performance and strength, some things had to be left out. It was the only way to meet the requiremnts, and Japanese pilots were considered expendable ... until veteran pilots fell into short supply. Then the new recruits were considered as expendable, but the veterans weren't.

Anyway, the Zero is as strong as a P-51 Mustang when everything is complete, but it rapdily loses strength when battle damage begins to accumulate. A lot iof the skin is .032" Aluminum instead of .040 or thicker, as on western fighters of the time .... but WE were flying more powerful engines and they weren't. The Nakajima Sakae was based on the Gnome-Rhome 14, but was a Japanese design and not interchangeable with the GR 14 at all. It was reliable, too, and still is.

Later, the A6M8 was designed with a 1500 HP engine, but never made it into service.

It might be interesting to point out the Me 109 was similarly design with minimalist design philosophy. There are three wing attach points. When all three are there, the plane is srtong and robust. If you lost one attach point, the wing departs company with the aircraft at the slightest provocation. That is why most American fighters have multiple wing attach points ... for ruggedness after sustaining battle damage. Of course, we are not the only people who do that, and I do not mean to imply that. 

I only mention the design practice since the Japanese designers were hamstrung by the available power and still managed to produce a lightweight fighter that could perform with the best in the world when it came out and for several years thereafter. Therein lies a pretty great achievement, even if at the expense of robustness. The fact that they didn't follow up with a more powerful design faster is not the fault of the designer or even of Mistubishi ... it was war and the IJA and IJN were responsible for not thinking of the long-term effects of sticking with a lightweight design when newer Allied fighters designed to combat the existing aircraft were coming down the pike.

The German high command was likewise responsible for the fact that they were still flying the Me 109 in 1945 instead of batches of Ta 152's and the like.

Other countries, the U.S.A., Great Britian, and Russia notably all fielded later designs that took into account for the opponents the previous generation of fighters were facing. If Japan and Germany had done the same, and had proceeded with the manufacture of same, things might have been much more "interesting" in 1945. Good thing for the Allies they didn't.

I can say this about our Zero at the Planes of Fame, it is strong, reliable, and VERY maneuverable ... just as designed. We are still flying on the same engine the airframe was captured with in 1945, and it is running just great!


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## evangilder (Apr 19, 2012)

ColesAircraft said:


> That's kind of a bizarre statement. In the first place none of these aircraft are pushed to their limits during airshow displays - especially the Chino Zero which is the only originally-powered Zero in the world and is flown very cautiously, as it should be. Secondly, how can anyone judge and compare performances of aircraft from the vantage point of the ground???


I am not judging it based on ground observations. I am basing it on conversations with people who actually FLY the aircraft that exist and fly today. 



ColesAircraft said:


> And, indeed, the myth that the Nakajima Sakae was a copy of any other engine originated in the bigoted environment of wartime when whites couldn't conceive that the Japanese were capable of independent ingenuity.


I have heard that argument before and from what I have read and seen, it had basis from other engines.


ColesAircraft said:


> I didn't post my information to start an argument. Just thought I'd share what I know, since the question was posed. My friend Naburo Harada, who owns several restored Zeros in Japan and oversees the Harada Collection (The Harada Collection), knows more than anyone on earth about this engine, the power to weight issue, and the consequences of not using the original Sakae.
> 
> Ron Cole



I am familiar with Mr Harada and while I respect his work and knowledge, he has never flown any of those aircraft. I have spoken with at 5 different people that have flown the Zero at Camarillo. There are currently two Zeros there. The second one showed up last August prior to the airshow and is a sister ship to the Camarillo one, both found on Babo Island airfield. 

Don't assume because I attend airshows and take photographs of airplanes that I don't know about them.


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## evangilder (Apr 19, 2012)

FLYBOYJ said:


> _View: https://www.youtube.com/watch?v=UmUseKNrh6Q_
> 
> I think Eric, knows this guy.  Says nothing about this aircraft's "airshow" performance being affected by the instllation of the 1830.




I do know him, and he has a lot of hours in that aircraft. He also has some great knowledge about this, and other aircraft.


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## GregP (Apr 20, 2012)

This discussion seems lively, doesn't it? The propeller on our Zero is Japanese and is interchangeable with a Hamilton Stanard since it was made under license in Japan to H-S drawings.

The Sakae 21 engine is Japanese and is NOT interchangeable with a Gnome-Rhone 14 or any other Gnome -Rhone. The Japanese made improvements and built their own design ... and it is reliable and well made. If you own the 1944 Fighter Conference proceedings, you will see that the Zero is the ONLY fighter in the group that didn't experience a mechanical failure in the flight tests. Surely that says SOMETHING about the Japanese Sakae 21 engine, huh? Ours still runs great every time we crank it up, and it's 70 years later. It is the ONLY example flying and it is DEAD reliable so, unlike the American or British or Russian radials, we have a population of ONE and it runs great all the time.

MTBF? ..... LONG .... in our experience ...

I'm impressed with it, even if it IS a lower-power engine.

Of course, I also think the Zero is the prettiest radial-powered fighter ever made ... and that may be personality fault that is not correctable ...


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## ColesAircraft (Apr 20, 2012)

Evanglider wrote: "Don't assume because I attend airshows and take photographs of airplanes that I don't know about them."


I assumed no such thing, as I never assume anyone I don't know and have never met is ignorant just because their information may be counter to what I thought I knew. But a few here don't extend to me the same courtesy. This is my first post here in two years. I shared what I know based on my life's work studying and writing about this subject - almost exclusively. That doesn't mean I know it all, and that doesn't mean people aren't entitled to completely disagree with me and say so. But I'm of the opinion that when someone takes the time to share their knowledge with others, it should be received with the grace with which it was provided - not picked apart for the sake of a good argument without so much as a polite "thank you". At the same time I admit that I find online forum discussion to be typically argumentative and sometimes abusive; it often rubs me the wrong way, which is why I rarely contribute. 

I shared my information, which was my intent. I'm an aviation artist. That's my living and my business. I don't have time to argue for the sake of arguing. To each his own, but that's not my idea of a wise expenditure of effort. I apologize if that sounds condescending.

As for what I wrote previously: I may not be pulling detailed stats off of Wikipedia but for most of my life I've broken bread with the men who actually fought in these machines, test flew them, and influenced their design. With all due respect I'm not going to have what I learned from those men, and elsewhere, overturned by anything anyone has to say here - at least insofar as wartime configurations are concerned. That the Zero's performance "suffers dramatically" without its original Sakae . . . I thought that was a universally accepted given fact. I've heard it from so many sources over the years that I can hardly quote only one, though Harada made it especially clear and he's absolutely in a position to offer valuable insight on the matter. I also recall a report written shortly after the CAF's Zero made its first test flights that confirmed that as well. Every Zero owner I know in the world goes to extreme lengths to try to find and restore an original Sakae for reasons other than originality - it's a requirement to make a Zero fly like a Zero! 

If anyone doesn't want to believe that or agree with it - that's fine. If anyone wants to be rude and fight over it - I have airplanes to paint. 


Ron Cole


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## ColesAircraft (Apr 20, 2012)

GregP said:


> This discussion seems lively, doesn't it? The propeller on our Zero is Japanese and is interchangeable with a Hamilton Stanard since it was made under license in Japan to H-S drawings.
> 
> The Sakae 21 engine is Japanese and is NOT interchangeable with a Gnome-Rhone 14 or any other Gnome -Rhone. The Japanese made improvements and built their own design ... and it is reliable and well made. If you own the 1944 Fighter Conference proceedings, you will see that the Zero is the ONLY fighter in the group that didn't experience a mechanical failure in the flight tests. Surely that says SOMETHING about the Japanese Sakae 21 engine, huh? Ours still runs great every time we crank it up, and it's 70 years later. It is the ONLY example flying and it is DEAD reliable so, unlike the American or British or Russian radials, we have a population of ONE and it runs great all the time.
> 
> ...




A terrific contribution! I once sat in that Zero with the engine running. That was years before the landing gear accident and I hear that another opportunity such as that will probably never happen again.  But it was glorious! I sat in the Raiden, too, thanks to Steve Hinton and a screwdriver - before Ed Malony had the cockpit of that aircraft spray painted metallic green. It was still all original Mitsubishi 'bamboo' at the time. My last visit with that bird, which is my favorite aircraft in the world, revealed the extent to which the spar cap exfoliation has taken its toll. Even in 1987 Steve warned me not to "move around too much" in the cockpit for fear of landing gear collapse. But short of a full and expensive restoration there is little that can be done. 

It was nice to hear from someone close to those birds. Speaking of which, I'm off.


Ron Cole


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## Vincenzo (Apr 20, 2012)

tomo pauk said:


> Maybe this one?



i think there is also an other maybe a modern one posted somewhere (highly probable in this forum, this is my most frequented forum so usual i read more here that in all other)


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## Vincenzo (Apr 20, 2012)

i'm not a engineer, not a mechanic and i not understand this things, even i've not the driving licence for car. But the GR 14K and Nakajima Sakae they look very different from the "numbers" bore and stroke are different (also the proportion are different), the GR-14K has around same weight with more displacement so the construction was different, etc..


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## evangilder (Apr 20, 2012)

As in other parts of life there are people that disagree. We all have different sources and different points of view on things. I have helped work on the CAF Zero, spoken with several of the pilots that fly the remaining Zeros as well as a couple of them that flew them during the war. 

I will agree that the survivors aren't flown like they were in wartime, nor should they be, but I don't agree that the performance "suffers" with the P&W. Thankfully, they're flown as historical displays now instead of weapons of war. I believe that most Zero restorers want the Sakae engines for two reasons; one, they are rare and valuable and two it makes the aircraft more historically accurate. Wartime performance and MEP are not key items for these birds now. Honestly, I don't care what engine it has in it, as long as it flies and people can see it. Besides that, no one can hear the engine in my photographs. 

Getting back to the original subject, I wouldn't call the Zero "Fragile". Lack of armor plate kept the plane lighter, and increased range and performance. Self-sealing fuel tanks weren't in some early American aircraft either. Some lessons are learned over time. 

In regards to the engines, I have heard the Gnome Rhone 14k variant, and have also heard that it was "derived" from the P&W Twin Wasp. The Japanese were indeed building license twin-wasps before the war and I would guess the engineers of the time studied all foreign aircraft engines to see where they could improve/modify them. Does that mean they copied them? No, but like any good engineer, I am sure that the Japanese engineers looked at the other works to see what worked and what didn't and how changes could be made to original designs to come up withe something better. Obviously, they succeeded.


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## FLYBOYJ (Apr 20, 2012)

ColesAircraft said:


> I shared my information, which was my intent. I'm an aviation artist. That's my living and my business. I don't have time to argue for the sake of arguing. To each his own, but that's not my idea of a wise expenditure of effort. I apologize if that sounds condescending.


 Ron, understand that on this site, there is a great wealth of information gathered, exchanged and debated and yes sometimes it turns into an argument. Like you many of us have spent many years around aircraft (I've been in the aviation business going on 34 years, have an A&P/IA, CFII and I have also worked on and flown several different war birds and jet aircraft), so when a "broad brush" comment is made, those of us who have worked on these war birds tend to question their validity and if there is something to be learned based on documented fact or direct information from a pilot of maintainer, even the better. I never thought you were condescending so please don't think any of our comments were, it's a matter of extracting and validating accurate information so we can all learn by each other's experience.

An old saying - validated performance numbers don't lie, oppinions can be debated!


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## Messy1 (Apr 20, 2012)

I have an old copy of Flight Journal, where Corky Meyer writes about testing, I believe it was the Aleutian Zero, and he mentions that the engine in the plane was a copy, or license built copy of a American engine. I'll have to pull the magazine for the accurate info, it's part of my bathroom library. But IIRC, he states the engine was a copy even down to the American company's logo (cannot remember which American company he is referring to), which had I believe the middle of the logo had been altered with a Japanese stamp or design in the middle of the logo? Anyone have any info on this? I have had this question on my mind for quite some time, and this seemed like a opportune time to ask. Is Corky Meyer incorrect? Anyone have any info? I'll pull the magazine and re-read the article to get the exact details as they were written. It may not have been Corky, but that is the name that is sticking in my mind.

Thanks in advance. Great thread by the way, and thanks to all who have contributed.


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## FLYBOYJ (Apr 20, 2012)

Messy1 said:


> I have an old copy of Flight Journal, where Corky Meyer writes about testing, I believe it was the Aleutian Zero, and he mentions that the engine in the plane was a copy, or license built copy of a American engine. I'll have to pull the magazine for the accurate info, it's part of my bathroom library. But IIRC, he states the engine was a copy even down to the American company's logo (cannot remember which American company he is referring to), which had I believe the middle of the logo had been altered with a Japanese stamp or design in the middle of the logo? Anyone have any info on this? I have had this question on my mind for quite some time, and this seemed like a opportune time to ask. Is Corky Meyer incorrect? Anyone have any info? I'll pull the magazine and re-read the article to get the exact details as they were written. It may not have been Corky, but that is the name that is sticking in my mind.
> 
> Thanks in advance. Great thread by the way, and thanks to all who have contributed.



_A number of other Zeros were captured by the Americans after the recovery of Koga's Zero in the summer of 1942, including a dozen A6M5s obtained after the fall of Saipan. A Grumman test pilot named Corwin H. "Corky" Meyer flew an A6M5a in October 1944 at a conference where the latest American, British, and captured enemy fighters were evaluated by test pilots in attendance. 

Much later, Meyer wrote an interesting memoir of his flights. Meyer said the Zero looked "every bit the fighter" and regarded it as the "best looking fighter at the meet." He found it a delight to fly, and was surprised at the quality of manufacture, since in America at the time and indeed well into the 1960s "made in Japan" was the same as saying "junk". "The workmanship was superb and comparable to American quality. This was most amazing in light of the prewar Japanese products with which most of us had come in contact." 

*Meyer noticed that the Sakae 21 engine announced its Pratt Whitney ancestry by conscientiously displaying the Pratt Whitney logo with an eagle on it and the English term "Quality Reliability", along with the Nakajima name in Japanese.* Although Meyer was 190 centimeters (6 foot 3 inches) tall, taller than any Japanese pilot, he found the cockpit surprisingly comfortable, though his feet felt tucked under him. He found one detail particularly interesting....

"Another un-American feature that must have given Japanese pilots mixed emotions was the protrusion of the 7.7-millimeter-type (0.303 caliber) gun butts six inches [15 centimeters] into the cockpit on either side of the instrument panel. I'm sure they gave a very macho feeling to the pilots when firing, with the racket, the nearness of the action, and the ability to unsort guns manually. With all the cordite fumes, I do hope the Japanese pilots had good 100% oxygen masks. Also, the gun butts must have been most disconcerting and disfiguring in a crash. _

The Mitsubishi A6M Zero


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## Messy1 (Apr 20, 2012)

That's it Joe. Thanks! Would this not make the Sakae 21 owe it's design in someway to P&W?


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## Vincenzo (Apr 20, 2012)

evangilder said:


> In regards to the engines, I have heard the Gnome Rhone 14k variant, and have also heard that it was "derived" from the P&W Twin Wasp.



Gr 14K was a distant derivative from Bristol Titan (a old, late 20s, 5 cylinders radial)


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## GregP (Apr 20, 2012)

Ron Cole,

Our J2M Raiden has some serious intergrannular corrosion issues, but is a beautiful aircraft. When we finish the Bell YP-59A, I'd love to take a crack at the Raiden! It would require a new wing spar and spar caps, not to mention many other items including longeron, but could be done. The only question is whether or not the Planes of Fame staff wants the Raiden to be restored or prefers it as-is.

As for the Zero engine:

The Nakajim Sakae 21 is a Japanese design, not P&W and not Gnome-Rhone. They used design features taken fromm other radials, but ALL radials do that ... or else they're completely different engines.

There are other two-row, 14-cylinder radials out there, but the Sakae 21 is not a copy of any of them as far as I know.

I don't know about the Zero needing a Sakae to fly like a Zero ... it would seem the powerplant would be unimportant as long as the weight and power are close and the RPM range is similar. However, I don't really KNOW, so I can't argue the point at all. I'll ask about the weight, power, and RPM and see what comes up. We can find the weight, power, and RPM on the internet, but I prefer to verify with actual pilots and mechanics on an original A6M5 Zero to trusting Wikipedia ... which is wrong almost as often as Obama.


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## ColesAircraft (Apr 20, 2012)

GregP said:


> Ron Cole,
> 
> Our J2M Raiden has some serious intergrannular corrosion issues, but is a beautiful aircraft. When we finish the Bell YP-59A, I'd love to take a crack at the Raiden! It would require a new wing spar and spar caps, not to mention many other items including longeron, but could be done. The only question is whether or not the Planes of Fame staff wants the Raiden to be restored or prefers it as-is.
> 
> ...




My understanding is that all other Sakae-like replacement engines are moderately larger than the Sakae and usually require new-build cowlings to accommodate them - at least that being the case with the A6M2 - and thus resulting in a host of modifications that go beyond just an engine swap, not to mention what that does to the center of gravity. Such issues resurrect the original problem with the Zero in terms of its relative inability to be modified in wartime to accommodate heavier equipment. It was the first aircraft in the world, it is believed, to have incorporated its duraluminum skin as a structural member. Before that, aircraft were structurally designed on paper to withstand certain forces, then covered to be aerodynamic - but that's how far the designers went to keep the Zero light. It doesn't suffer added weight well, in any form.

It's been my dream to see the Raiden restored, but I don't have much hope for that in the near future given its condition and the fact it most probably can't ever be made airworthy again. I know that it had languished outside in a park for many years before Ed acquired it. By then corrosion was already a problem and the aircraft suffered much from pilfering. The cockpit is still relatively complete - except for its gun sight, some instruments, and its throttle quadrant. I inspected the inside of the fuselage, and noted that it had been built at a period in the war when the previously standard Aotake primer had not been applied. There was an even coating of light corrosion plainly visible throughout and was probably worse where I couldn't see - but the original stenciled factory-painted serial number placard was still there! God knows what the inside of the wing looks like though. Today the wings noticeably sag, there's usually some exfoliated aluminum on the floor from were it falls off the exposed spar caps, and the left landing gear must have partially collapsed sometime recently - as there's relatively new damage to the wheel well area near the gear strut.

Someone please save her! 


Ron Cole


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## FLYBOYJ (Apr 20, 2012)

ColesAircraft said:


> My understanding is that all other Sakae-like replacement engines are *moderately larger *than the Sakae and usually require new-build cowlings to accommodate them - at least that being the case with the A6M2 - and thus resulting in a host of modifications that go beyond just an engine swap, not to mention what that does to the center of gravity. Such issues resurrect the original problem with the Zero in terms of its relative inability to be modified in wartime to accommodate heavier equipment. It was the first aircraft in the world, it is believed, to have incorporated its duraluminum skin as a structural member. Before that, aircraft were structurally designed on paper to withstand certain forces, then covered to be aerodynamic - but that's how far the designers went to keep the Zero light. It doesn't suffer added weight well, in any form.



From what I understand the Camarillo Zero's cowl is actually the same size as the original Zero cowl however there were internal components altered to accommodate the slightly larger P&W engine and again from what I understand the size difference is nominal. Eric might be able to get info on that as he's a regular around that aircraft but from what I read about the two engines the difference in diameter is about 3 inches. C/G issues in minor structural mods are usually non events and many times are easily remedied by using ballast in the nose or tail, if even necessary. As a matter of fact sometimes ballast is necessary to compensate for obsolete wartime equipment (mainly radios) removed during the restoration.

I don't believe the Zero was first aircraft to incorporate aluminum (or duralumin) skin as a structural member. I can recall portions of the DC-3 that had skin carrying a structural load and were repair sensitive if damage was over a certain size.


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## ColesAircraft (Apr 20, 2012)

FLYBOYJ said:


> From what I understand the Camarillo Zero's cowl is actually the same size as the original Zero cowl however there were internal components altered to accommodate the slightly larger P&W engine and again from what I understand the size difference is nominal. Eric might be able to get info on that as he's a regular around that aircraft but from what I read about the two engines the difference in diameter is about 3 inches. C/G issues in minor structural mods are usually non events and many times are easily remedied by using ballast in the nose or tail, if even necessary. As a matter of fact sometimes ballast is necessary to compensate for obsolete wartime equipment (mainly radios) removed during the restoration.
> 
> I don't believe the Zero was first aircraft to incorporate aluminum (or duralumin) skin as a structural member. I can recall portions of the DC-3 that had skin carrying a structural load and were repair sensitive if damage was over a certain size.




The latter may be true. I only know that Jiro Horikoshi's design team had tried and failed to design on paper an aircraft capable of meeting the Navy's specifications due to weight until Mr. Horikoshi had the idea, presented as independently derived at, to incorporate the aircraft's skin in the design itself as a structural component. I think arguably the Junkers J.1 was probably the first aircraft anywhere to incorporate this idea - though very differently. But that's not the only instance of problem solvers independently arriving at similar, but not copied, solutions: another example being oblique firing cannon. 

Someone also mentioned earlier that the Zero's controls "turned to concrete" at high speeds. True. I've heard it cynically stated that Kamikaze pilots would often have been unable to pull out of their dives even if "sense" came to them in their final moments. I know that, at least for the Japanese, rigidity in the control cable system was a required priority in aircraft design - until the Zero. Horikoshi's problem with the new aircraft was its unprecedented speed and the fact that as its speed increased there was a dramatic increase in the sensitivity of its controls. This was discovered during the A6M1's first test flight, along with vibration problems due to the two blade propeller (which was then switched to a three bladed variant). The rigid control cables of the prototype were replaced with cables that would 'give', and that solved the problem: as wind resistance on the control surfaces increased, the give in the control cables compensated, and the pilot did not experience the over sensitivity to input previously suffered at higher speeds. But what Horikoshi did not mention was how that solution impacted control at dive speeds. "Concrete" is thus an apt description for it.

All of this highlights some of my original point regarding Japanese philosophy and how it was independent of limitations posed by technology or economics. I understand that accepted theory, in the West at least, states that the Japanese merely made do with the best that they were capable of producing, maneuverable but under powered Zeros being in part the result. But I (obviously) disagree. Japanese aircraft were designed and produced for the offensive, and their doctrine emulated that as well. The Zero wasn't designed with armor plate in part because theoretically it would never be within enemy cross hairs to be hit in the first place. Yes, some of that was based upon pragmatic considerations of how armor would sacrifice performance, but there was also an element of uniquely-Japanese confidence within it. Why should the Zero ever need to escape a dogfight by diving, when it will rule every opponent it faces? These men typically refused to wear parachutes until late in the war, when they were ordered to - even then often using them only as seat cushions. Such wasn't fighter pilot bravado - it was indicative of a culture that permeated design boards and industry as well as the men at the front. A Japanese pilot was expected to maintain the initiative or fail, to fail meant death, and their equipment was designed with that idea in mind at the expense of everything else. Were they "fragile" machines by Western standards, incapable of taking hits? Absolutely. The Americans didn't nickname the G4M the Flying Lighter without good reason. But these things were not regarded by the Japanese as design faults until after the fact, when losses mounted and the fate of their culture demanded that they rethink their original ideas and adopt designs employed by their more successful enemies. To judge an aircraft like the Zero fairly, I think it should be seen at least in part through the eyes of its designers; in that it did exactly what it was designed to do, exceeding all expectations, sacrificing only that which was considered expendable. 

The Japanese did not largely dispense with using parachutes because their industry could not manufacture them, and when the Japanese wanted to build heavy fighters with powerful engines (like the Shoki and the Raiden) the Japanese built them, and they were good machines. Thus the Zero was a product of a philosophy - not technological or economic frailty. 


Ron Cole


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## ColesAircraft (Apr 20, 2012)

FLYBOYJ said:


> Ron, understand that on this site, there is a great wealth of information gathered, exchanged and debated and yes sometimes it turns into an argument. Like you many of us have spent many years around aircraft (I've been in the aviation business going on 34 years, have an A&P/IA, CFII and I have also worked on and flown several different war birds and jet aircraft), so when a "broad brush" comment is made, those of us who have worked on these war birds tend to question their validity and if there is something to be learned based on documented fact or direct information from a pilot of maintainer, even the better. I never thought you were condescending so please don't think any of our comments were, it's a matter of extracting and validating accurate information so we can all learn by each other's experience.
> 
> An old saying - validated performance numbers don't lie, oppinions can be debated!



I apologize for getting piqued on the forum. My somewhat younger wife reminds me that a forum thread is not the same as guys talking at a table - though I stubbornly tend to brush off the idea that the etiquette should be any different. I sign my full name to what I write, removing 'anonymity' without a thought, and unintentionally making the discussion personal. I just assume that without signing my name, what speaks for my credentials when I spout off like a know-it-all? 

But I was only trying to constructively add to the discussion, offering my information as points of potential interest. My history with Japanese aviation has very much been influenced by the Japanese perspective, as most of my connections to same have been the Japanese themselves. That is very different than what one might glean from the modern restoration and operation of these aircraft and their modern modifications - though I don't claim one perspective is superior to the other. 

I'm reminded of how Japanese veteran pilots almost always refused to autograph Western-painted aviation artwork (in contrast to the vets of other nations - including Germany). In spite of all the handshaking and goodwill between former enemies that went on, there remained from the Japanese side a certain shame mixed with stubborn pride and a trace of bitterness - that the West was taking something from them that it had no right to take when it painted their airplanes - usually flaming at the guns of a P-40 - or restored a Zero for primarily Western air shows. These are somewhat generalizations, of course, but in my circles it was always taken for granted that the Sakae was an "irreplaceable" engine - for example - and that the Zero's performance "suffered dramatically" with an American made stand-in. I still believe that's true, though concede that some prejudice may be evident here from both sides. A real, unbiased, test regarding the matter would be interesting. 


Ron Cole


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## cherry blossom (Apr 20, 2012)

The story of “Corky” Meyer seeing the Pratt Whitney logo with an eagle and "Quality Reliability" seems to be true. Similarly the picture at 01 three dollar bill G W Bush « Voices from Russia has the words “Federal Reserve Note”. However, I do not believe that the Nakajima Sakae has a close relationship with any Pratt Whitney engine. Apart from little details like having different bores and strokes, there is the point that all the valves are driven from in front in the Sakae while P&W two row radials drove the valves of the back row from behind. 

On the subject of the A6M needing a Sakae to fly like a Zero, the A6M8 was accepted for production with a Kinsei. However, it did seem to be slower than it should have been which has produced two threads over at J-aircraft Was drag a significant factor in the lack of real performance with the A6M8? and A6M8 performance.


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## ColesAircraft (Apr 20, 2012)

cherry blossom said:


> The story of “Corky” Meyer seeing the Pratt Whitney logo with an eagle and "Quality Reliability" seems to be true. Similarly the picture at 01 three dollar bill G W Bush « Voices from Russia has the words “Federal Reserve Note”. However, I do not believe that the Nakajima Sakae has a close relationship with any Pratt Whitney engine. Apart from little details like having different bores and strokes, there is the point that all the valves are driven from in front in the Sakae while P&W two row radials drove the valves of the back row from behind.
> 
> On the subject of the A6M needing a Sakae to fly like a Zero, the A6M8 was accepted for production with a Kinsei. However, it did seem to be slower than it should have been which has produced two threads over at J-aircraft Was drag a significant factor in the lack of real performance with the A6M8? and A6M8 performance.



Ah! Good old reliable J-Aircraft.com! 

My understanding of the A6M8 is that the aerodynamic efficiency - or lack thereof by mid '40s standards - of the Zero's fuselage design had become an obstacle. The Japanese were perfectly aware of what worked better by the time the A6M8 was in the works, and in fact put such knowledge into the design of the incredibly fast and aerodynamically efficient C6N "Myrt" (the fastest multi-seat single-engine production aircraft of WW2). But the fuselage of the Zero was largely a mirror of its successful predecessor, the A5M "Claude" - which itself was designed in 1934! 

The A6M8 had a slightly larger cowling than its predecessor models, but I don't think that counts for drastically increased inefficiency. The firewall behind it remained unchanged. But though it's hard to articulate in words: the Zero's fuselage was tapered in a curve (like a backwards rifle bullet) unlike more modern designs as employed in the C6N, and was not as aerodynamically efficient. Proving that this attributed to the retardation of the A6M8's top speed is probably impossible - but it makes sense as a major culprit. In the end the Zero was never especially fast by WW2 standards. Even the A6M3 fell short of expectations in terms of speed, in spite of clipping its wings, and the D4Y "Judy" that was in service by mid-1942 could walk away from it - and the "Judy" was a dive bomber! 


Ron Cole


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## GregP (Apr 20, 2012)

You might like to hear the story of the planes of Fame A8M5 Model 52 Zero when it went to Japan the first time.

There is no general aviation in Japan. It is all either commercial or military. Today there are a smattering of ultralights, but nothing like we have. Consequently, their airports are not designed like ours and there are no or few windows in hangars, and little way to look out except to open the hangar door. When our Zero was shipped over to Japan, we (the "We" is the Planes of Fame people, I wasn't even a volunteer yet) took it inside a hangar, assembled and test ran it.

When the time came to present it to the crowd, nobody was sure if we'd have any people there, be it 4, 40, 400, or 4000. Nobdoy knew, including the sponsors of the event (flying an authentic Zero over Mount Fuji). When they opend the hangar, there were 1.4 million people out there! Everyone was overwhelmed. We trundled out the Zero, started it, took off and made several passes, then did the photo flight over Mount Fuji. When the Zero returned, about 100 ex-Zero pilots were allowed to sit in the cockpit again for a time, and they came back next day to see it again. It was HUGE hit and everyone had thought the people would be ashamed of the Zero ... but they were very happy to see it, and were especially happy to see it not only run but also fly. 

They sang WWII songs when it flew over.

Our Zero has been to Japan twice, and the engines were restored with the help of Nakajima (Fuji Heavy Industries) and Mitsubishi.

Just some info on the Zero ... Cheers!


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## Jenisch (Apr 20, 2012)

By estimated data of the A6M8 performance, it doesn't look much different from the N1K2-J.


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## Jenisch (Apr 20, 2012)

GregP said:


> and Japanese pilots were considered expendable!



I already read this from an interview with Saburo Sakai. This is funny, since the IJN pilots specially, probably had the hardest selection and training in the world before the war.


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## GregP (Apr 20, 2012)

Post #64: No, but it was better than the A6M5 ...


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## ColesAircraft (Apr 20, 2012)

Jenisch said:


> I already read this from an interview with Saburo Sakai. This is funny, since the IJN pilots specially, probably had the hardest selection and training in the world before the war.




I don't think they were so much regarded as expendable in the sense that they were not valued as important national assets, they were, as the investment in their training indicated. But the Japanese thought of war in terms of the one war they'd actually fought - and won: the war with Russia in 1904/05. They anticipated a quick decisive battle where attrition played no role, and whatever they had on hand when the war started - in terms of equipment and manpower - would be what they'd win it with. Casualties were expected, but that's what the hard training was meant to minimize, and in the end they believed that their smaller and better trained elite force would overcome whatever was put into its path. Some of the more worldly Japanese elite, such as Isoroku Yamamoto, saw the flaws in this way of thinking - but it was still largely a part of Japanese national identity in the 1930s and '40s. 


Ron Cole


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## evangilder (Apr 21, 2012)

Greg, have you ever had a tour bus of Japanese arrived at the POF? We had a couple show up at Camarillo and Steve Barber, who is in a video earlier in this thread took the Camarillo Zero up for the folks to see. It was really something, and they ate it up. 

I spent my first few years at Camarillo moving around the Zero that was in two pieces (now at the Pacific Museum on Ford Island) and I was always amazed at how light the tail structure was. We had it on a customer fit dolly and it was no problem for one person to shift it around. There are 2 flyable Zeros in the hangar right now, until later in the spring when the second one will be departing to Alaska. The crew chief on the Camarillo Zero is Japanese and he knows the aircraft quite well. He has corresponded with Mr. Harada on several occasions.

There is something neat about seeing a Zero fly, especially knowing the rarity of them. Regardless of what the performance is with the P&W, they have demonstrated the Zero with the Hellcat on a few occasions and you can clearly see a difference in the turn capability at slow speeds. The "like concrete" statement was something that was told to me by Steve Barber, who has flown the Zero a lot.


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## krieghund (Apr 21, 2012)

With regards to the performance of the A6M8 one needs to look at the pictures of the aircraft and see the differences between the Sakae cowling and the Kinsei cowling.

Posted here: http://www.ww2aircraft.net/forum/flight-test-data/looking-ki-43-hayabusa-data-30779-2.html

One needs to rethink the low altitude performance of the A6M8 with an extra 400 to 500 BHP available.


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## jim (Apr 21, 2012)

Mr Cole
Thank you for providing your extensive knowledge on japanese aircrafts
I would like to ask you three qustions
1) I have read somewhere that japanese had very good metelourgy and could built thinner aircraft skins without sacrificing strength, so saving weight. Do you confirm it?
2) Also, many years ago, i have read that in order to save weight , japanese constructed their wings on a single piece or something like that. Do you know anything about that?
3) Japanese used combat flaps in their later fighters apparently with good results. However no other nation used them . Do you have any explanation?
Thank you in advance


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## ColesAircraft (Apr 21, 2012)

jim said:


> Mr Cole
> Thank you for providing your extensive knowledge on japanese aircrafts
> I would like to ask you three qustions
> 1) I have read somewhere that japanese had very good metelourgy and could built thinner aircraft skins without sacrificing strength, so saving weight. Do you confirm it?
> ...



Jiro Horikoshi is my source to confirm the assertion that the Japanese had developed a 'duraluminum' that was purportedly more advanced and lighter in weight than other nation's industries, and was utilized in the Zero fighter. As for it being thinner - I can't confirm that. I have pieces of many Japanese aircraft in my collection, as well as comparable parts of American, German, British, and Russian machines. The thinnest by far seems to have been of Russian origin, but you can also tie the stuff in a knot - almost - it's so malleable. But thicknesses would differ from one panel to another. Japanese wartime metallurgy seems to have been very inconsistent. The only real post-war scientific studies ever conducted, that I know of, were of Japanese steel by the U.S. Navy - specifically steel armor plate in their warships. The results ranged from identifying some of the best steels ever tested - to garbage. 

I'm not sure about your second question. Japanese aircraft were uniquely designed to be modular (wings and fuselages could break down into transportable components), but if anything incorporating that feature might have added weight. They did go to great lengths to reduce the number of rivets required in an aircraft design - as was most glaring in the design of the C6N "Myrt", the design of which was detailed extensively in a series run in the 1970s by Koku Fan magazine - to save weight. 

The Japanese first used combat flaps in the Ki-43 "Oscar" fighter - first flight tested with combat flaps in 1939. I can't say why (or even if) other nations were less inclined to study this technology - but, again, the Japanese were wedded to the idea of the 'light fighter' and in the pursuit of that goal pushed every envelope to make lightweight and maneuverable aircraft. This was not due to an inability to make powerful engines - as has been asserted. It came from experience in China against other light fighters, such as the I-16. Surely the Japanese would have welcomed a more powerful engine for the Zero in 1939 and later - but not at the expense of weight that would have impacted other 'light fighter' performance priorities. The Raiden proves my point: it was the opposite of the Zero fighter in many ways, yet was designed by Mr. Horikoshi's team almost side-by-side with the Zero (though took much longer to reach prototype stage). The plane was built around its then powerful 1500 bhp (later 1850 bhp) Kasei engine. It's rate of climb was spectacular, it was fast - and, like the Gee Bee racer it vaguely resembled - handled like a truck.* 

Thanks for your comments!  Japanese aircraft are extremely interesting machines - even for no other reason they they were so different.


Ron Cole


* Incidentally, the Wikipedia page on the Raiden makes it sound like the aircraft was a general flop. Not true. It was regarded by American pilots, encountering the type over the Philippines, as a fearsome opponent that spoiled their developed tactics - referring to it as a "super Zero" - and were quick to warn fellow pilots of it. Notorious Japanese ace pilot Sadaaki Akamatsu loved the aircraft, and boasted that his favorite "prey" was the P-51 - several of which he shot down while at the controls of his Raiden (Though his claims tended to increase with his consumption of alcohol). But few Japanese pilots knew how to play to its strengths, trying to fly it like it was the Zero that most had flown previously. Saburo Sakai test flew the plane and disliked it - but not as much as he disliked the later N1K2 "George" - which he claimed was "a second rate plane from a second rate company".


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## tyrodtom (Apr 21, 2012)

The Japanese weren't the only ones to have combat or manuvering flaps. The P-38 had a specific setting for it and other aircraft could do the same , if they had adjustable flaps that could be deployed at speed, by just dropping a few degrees of flap.

But most allied pilots , if they were thinking, would not attempt to out turn most Japanese fighters.


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## ColesAircraft (Apr 21, 2012)

Here's a frame from an old Japanese comic strip that I stumbled across that alludes to the whole 'powerful engine/light fighter' issue. I think it humorously speaks for itself: 







Ron Cole


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## Jenisch (Apr 21, 2012)

Coles, a modeler's question: since you have talked with many Japanese veterans, you already ask them if they remember the colors of aircraft in which there's no data or evidence avaliable?


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## jim (Apr 21, 2012)

Mr Cole
Thanks for your respond. 
I find strange the comments about Raiden. A member of this forum has uploaded a comparison test between J2M and F6F5 . Raiden using combat flaps appeared to be generaly more manouverable on that test report
It appears that the requeste for manouverability was strong even in 1945. According to wiki A7M2 prototype had ...152 kgr/m2 wingloading ( from 30m2 wing area!) plus combat flaps. Even Yak 3 had 181 kgr/m2! 
Or Ki84 . While considered more balanced desigh than the previus japanese fighters , with a loaded weight of 3616 kgr was much lighter than western fighters of its time. On paper has extremely good power and wing loadings. Much better even than F8F. But how such a low weight was possible? 800kgr lighter than an Fw 190A8 !! And Ki 84 had larger wing area!


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## ColesAircraft (Apr 21, 2012)

Jenisch said:


> Coles, a modeler's question: since you have talked with many Japanese veterans, you already ask them if they remember the colors of aircraft in which there's no data or evidence avaliable?



Actually, yes. Believe it or not, among Japanese aircraft 'experts', the subject of what these aircraft were painted arouses furious debate - the most toxic being the rage around what shade of gray early Zeros were painted. But I digress. I've always asked color questions, as a modeler myself. The problem is in interpretation and memory, as I've gotten some pretty strange replies sometimes. 

In recent years, though, a whole wealth of new information has surfaced regarding Japanese aircraft colors - inside and out. An original Japanese Navy color specification book was unearthed in Japan, including large paint samples for most everything that the Navy specified for the different manufacturers. More surviving Japanese aircraft, and aircraft pieces, have been discovered in the world, and documented - especially in China and Indonesia. 

What information are you specifically looking for?


Ron Cole


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## ColesAircraft (Apr 21, 2012)

jim said:


> Mr Cole
> Thanks for your respond.
> I find strange the comments about Raiden. A member of this forum has uploaded a comparison test between J2M and F6F5 . Raiden using combat flaps appeared to be generaly more manouverable on that test report
> It appears that the requeste for manouverability was strong even in 1945. According to wiki A7M2 prototype had ...152 kgr/m2 wingloading ( from 30m2 wing area!) plus combat flaps. Even Yak 3 had 181 kgr/m2!
> Or Ki84 . While considered more balanced desigh than the previus japanese fighters , with a loaded weight of 3616 kgr was much lighter than western fighters of its time. On paper has extremely good power and wing loadings. Much better even than F8F. But how such a low weight was possible? 800kgr lighter than an Fw 190A8 !! And Ki 84 had larger wing area!



The Zero and the Ki-61 "Tony" were the only Japanese fighters not to employ 'butterfly' or combat flaps - but that didn't make the Raiden into an effective dog fighter. No doubt they helped, but the impressions remembered by pilots of the type were not favorable to the Raiden's maneuverability. Maybe Akamatsu would have proffered a different first-hand opinion, but he died in 1984.

The Raiden's maneuverability problem was fundamental: it boasted a gigantic engine on a small fuselage with small wings. It was a Gee Bee with cannon and armor plate. Maneuverability wasn't ignored by its designers, but it wasn't a priority over rate of climb. 


Ron Cole


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## evangilder (Apr 21, 2012)

Ok, I do have one question. I am reading about the Flying Tigers and they are encountering "Hayabusas" in the battle for Burma. I am trying to figure out which aircraft they are talking about with Hayabusas. They said they were retractable gear fighters. I will have to dig a little in the previous chapter to see what Kokutai they were in.


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## Jenisch (Apr 21, 2012)

Thanks Coles.

You know, I think there's more lack of information in the West than lack of information itself. You see, not today, but in the first decades after the war, there were many veterans and factory workers that were still young and with good memory, I beat they provided this info.

I'm not looking for othing in specific at the momment, I just would like to see what a pilot from a Ki-44 or other still unknow type would tell if asked what color the cockpit was painted. I have some Maru Mechanic books, and I belive the cockpit colors in them were painted according to the veterans, and it's really strange sometimes.

Other question: the Zero and Ki-43 pilots belived their machines were adequate against early war Allied types such as the P-40 and the Wildcat?


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## ColesAircraft (Apr 21, 2012)

evangilder said:


> Ok, I do have one question. I am reading about the Flying Tigers and they are encountering "Hayabusas" in the battle for Burma. I am trying to figure out which aircraft they are talking about with Hayabusas. They said they were retractable gear fighters. I will have to dig a little in the previous chapter to see what Kokutai they were in.



Probably the 64th Kokutai, but I'd have to look it up. 'Hayabusa' is literally Japanese for 'Peregrine Falcon' and, in Japanese vernacular, refers specifically to the Ki-43 series of fighters, or "Oscars". In 1942 that would have been the Ki-43 I with the two-bladed propeller, one of which is preserved in Australia. The Japanese still pay homage to the original WW2 Hayabusa by having named one of their first spacecraft after it, and the world's fastest production motorcycle.


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## FLYBOYJ (Apr 21, 2012)

ColesAircraft said:


> Jiro Horikoshi is my source to confirm the assertion that the Japanese had developed a 'duraluminum' that was purportedly more advanced and lighter in weight than other nation's industries, and was utilized in the Zero fighter. As for it being thinner - I can't confirm that. I have pieces of many Japanese aircraft in my collection, as well as comparable parts of American, German, British, and Russian machines. The thinnest by far seems to have been of Russian origin, but you can also tie the stuff in a knot - almost - it's so malleable. But thicknesses would differ from one panel to another. Japanese wartime metallurgy seems to have been very inconsistent. The only real post-war scientific studies ever conducted, that I know of, were of Japanese steel by the U.S. Navy - specifically steel armor plate in their warships. The results ranged from identifying some of the best steels ever tested - to garbage.



"Duraluminum" is more or less a marketing name for 2024 aluminum. During WW2 it was known at "24T." It is basically aluminum alloyed with copper and has traces of magnesium and manganese in it as well. 2024 or similar alloys were widely used for aircraft skins although I do know that the Soviets used an aluminum similar to 6061. 

2024 can be tempered to meet various stress requirements calculated by engineers. The material can go from being extremely malleable but weak in the annealed condition to hard and brittle in some of it's tempered conditions.

2024 was first used in the construction on Zeppelins. 

2024 can be made foil thin to rather thick depending on how it's tempered. If I remember there are about 15 different basic temper designations but in today's world you commonly see -O, T-3, T-351 and T-6.


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## evangilder (Apr 21, 2012)

ColesAircraft said:


> Probably the 64th Kokutai, but I'd have to look it up. 'Hayabusa' is literally Japanese for 'Peregrine Falcon' and, in Japanese vernacular, refers specifically to the Ki-43 series of fighters, or "Oscars". In 1942 that would have been the Ki-43 I with the two-bladed propeller, one of which is preserved in Australia. The Japanese still pay homage to the original WW2 Hayabusa by having named one of their first spacecraft after it, and the world's fastest production motorcycle.



Thanks, the 64th sounds right. I was thinking that before I typed it but wanted to look it up. I had heard rumors of Zeros against the AVG, but I am guessing it was the Oscars they were facing. I haven't seen any evidence to indicate any Zeros at the time. It's an interesting history that I am reading which compares the claims to the actual losses in the records of both the Americans and the Japanese. Both sides overclaimed, although it isn't terribly surprising when you look at the battle as told by different people. That is often the case, two people side by side in the same firefight can have vastly different views by how they took in the information, especially under duress.


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## ColesAircraft (Apr 21, 2012)

Jenisch said:


> Thanks Coles.
> 
> You know, I think there's more lack of information in the West than lack of information itself. You see, not today, but in the first decades after the war, there were many veterans and factory workers that were still young and with good memory, I beat they provided this info.
> 
> ...



Exterior colors for Japanese military aircraft seem to have been usually specified by the military services and did not differ significantly between manufacturers (but not always, early Nakajima-built Zeros were painted a different shade of gray than Mitsubishi-built Zeros, for example), but such was not the case with interior colors.

As a general rule: Japanese aircraft manufacturers outsourced many components to myriad small companies, each using its own paint and colors when painting was required. Thus the landing gear legs of many Japanese fighters were gloss black, including the Zero. Why? That's what the company that made the landing gear used. The same was true of all sorts of components, for the cockpit as well. The only military mandate that effected interior color was the one regarding corrosion prevention, and thus it was required that all aircraft manufactures use Aotake primer to cover all interior aluminum - inside the wings, everywhere. This coating was a clear coat that was mixed with a blue/green tint to make it visible. It served the same purpose as zinc chromate for the Americans, but in tests proved more effective at preventing corrosion. Until later in the war it would be found everywhere, in every aircraft, including crew areas. Many manufacturers, however, painted over the Aotake, and many outsourced parts, with their own paints for crew areas. Mitsubishi did this throughout the war, which is why Zeros and "Bettys", etc., had mat olive green cockpit areas. I've never heard why, but since the Aotake was glossy it might have been a glare concern.

The Ki-44 was a Nakajima product. Since there are no Ki-44s in existence (Except the wings preserved in China - do they have the rest? No one seems to know!) we have to look at other Nakajima-built aircraft for evidence. There are few of them around. I have several cockpit airframe pieces from a B5N2 "Kate" that reveal two different olive greens in use in the cockpit - but alas, this was a rare license-built Aichi airframe! The NASM's J1N1 "Irving" was built by Nakajima and it retains its Aotake primer in the cockpit with all the different colored components. The same seems to be true of Nakajima's Ki-43 "Oscar". Thus it's safe to suppose that the Ki-44's cockpit would be Aotake blue/green, glossy, and filled with lots of different colored parts: probably dark green for radio components, black for the instrument panel, etc.

Hope that helps! It's a long-winded explanation, but the whole subject of Japanese cockpit colors can be a study in itself! 


Ron Cole


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## ColesAircraft (Apr 21, 2012)

evangilder said:


> Thanks, the 64th sounds right. I was thinking that before I typed it but wanted to look it up. I had heard rumors of Zeros against the AVG, but I am guessing it was the Oscars they were facing. I haven't seen any evidence to indicate any Zeros at the time. It's an interesting history that I am reading which compares the claims to the actual losses in the records of both the Americans and the Japanese. Both sides overclaimed, although it isn't terribly surprising when you look at the battle as told by different people. That is often the case, two people side by side in the same firefight can have vastly different views by how they took in the information, especially under duress.




My pleasure! I was actually going to mention the American use of terms like 'Hayabusa' and 'Zero' in my original reply, as in fact they can cause some confusion today. The Allies routinely called any Japanese fighter they encountered a 'Zero' - no matter what it was. I have volumes of USMC 'kill' claims from the war, and among the thousands of encounters listed I think in total there are more 'Zero' losses claimed than there were Zeros actually built. The practice comes out in post-war written accounts as well. If it had one engine and turned like the devil - it was a 'Zero', or sometimes a 'Hayabusa'. 

Yeah, eye witness claims can sometimes cause more heartache than they resolve. They've fueled the mildly ridiculous feuds over what color early Zeros were actually painted, for example, as different people heard different information from different vets who swear they flew planes painted everything from chalk white to pale brown. But studying actual aircraft parts for evidence can be just as confounding. I recently obtained these preserved pieces of fuselage from an Fw190A-8 excavation, and from what they reveal this aircraft was painted red, yellow, blue, gray, a bunch of different greens, and black. 

?????!!!!!!


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## ColesAircraft (Apr 21, 2012)

Regarding Japanese aircraft construction and cockpit colors, I might suggest checking out the link to a section devoted to the subject on my website:

Japanese Aircraft in Detail JAPACDET

One area is dedicated to some amazing and high quality photos taken during the construction of the N1K1 "George" prototype by the official Kawanishi photographer, detailing each step in the construction process - start to finish. Even disregarding the technical value, it's striking to see the factory workers wearing sandals and tabi socks!

Another area that's unique is a series of photos taken by the Russians of a captured and dismantled A5M "Claude" fighter. Amazing stuff. It's a compilation of the best of most unique photos I've ever found.


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## FLYBOYJ (Apr 21, 2012)

GREAT SITE!


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## Jenisch (Apr 21, 2012)

Interesting.

About the A5M, the Russians regarded the machine has very good, as they also regarded the Ki-27 and it's pilots.


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## ColesAircraft (Apr 21, 2012)

FLYBOYJ said:


> GREAT SITE!



Thank you! Some of the pictures are a little small (now that I revisit it after a time) - I'll try to fix that.


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## ColesAircraft (Apr 21, 2012)

Jenisch said:


> Interesting.
> 
> About the A5M, the Russians regarded the machine has very good, as they also regarded the Ki-27 and it's pilots.



The Japanese performed poorly in the Nomonhan Incident with Russia, in which Ki-27s were pitted against Soviet air forces, but not in the realm of air power. The Japanese Air Force in the area was grounded by the Japanese government in Tokyo after they had successfully attacked a Russian airfield, so as to avoid escalating the conflict. That left General Zhukov (later to take Berlin) free to counterattack with overwhelming forces. Nevertheless, the Ki-27 was thought to have performed well.

Russian respect for Japanese air power and pilots came more indirectly from their volunteers in China, who generally speaking were consistently outmatched unless attacking unescorted bomber formations - from which the Navy learned the value of possessing fighters with longer range. The Russians eventually bought several Japanese aircraft captured by the Chinese, including the A5M, Ki-27, and Ki-10. Reports regarding the new Zero were received by all parties involved in the region - but were generally not taken seriously.


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## evangilder (Apr 21, 2012)

Nice! I really like the painting of the captured P-40 with the Zero. The color scheme on the Zero in that painting is very much like the Camarillo Zero.


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## ColesAircraft (Apr 21, 2012)

evangilder said:


> Nice! I really like the painting of the captured P-40 with the Zero. The color scheme on the Zero in that painting is very much like the Camarillo Zero.




Thank you. I used a picture of that A6M to work from!


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## evangilder (Apr 21, 2012)

I know there are at least a couple of guys that have used that for basis of artwork. The yellow leading edges and the white around the roundels do make for a good looking bird. I had heard about the captured P-40 and it was apparent that they captured a few during the battle of Burma, but that was the first photo I have seen of one.


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## cherry blossom (Apr 22, 2012)

ColesAircraft said:


> Jiro Horikoshi is my source to confirm the assertion that the Japanese had developed a 'duraluminum' that was purportedly more advanced and lighter in weight than other nation's industries, and was utilized in the Zero fighter. ....


I tried using Google on this and the best hit came up as a thread here five years ago http://www.ww2aircraft.net/forum/aviation/question-about-a6m-duraluminum-9908-2.html which Flyboy should remember as he contributed. Micdrow contributed on Extra-super-duraluminium, ESD, that "The ESD was used on the Zero but not for the skin, It was used for what is usually the most single heaviest member of the structure, The main wing spar." The point was that ESD was stronger but it was subject to corrosion. Other countries rejected it and Japan was alone in using it, rightly as it turned out, because they realised that aircraft would not last long in a war.


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## FLYBOYJ (Apr 22, 2012)

Yep and remember it well. On that link I have all the aluminum temper designations. As stated the ESD probably was closer to 7075. Aluminum and copper alloyed together make a strong structure but is very susceptible to corrosion, that's one of the reasons 2024T skins are usually "alclad" in they have a layer of aluminum over the skin to prevent corrosion.


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## ColesAircraft (Apr 22, 2012)

cherry blossom said:


> I tried using Google on this and the best hit came up as a thread here five years ago http://www.ww2aircraft.net/forum/aviation/question-about-a6m-duraluminum-9908-2.html which Flyboy should remember as he contributed. Micdrow contributed on Extra-super-duraluminium, ESD, that "The ESD was used on the Zero but not for the skin, It was used for what is usually the most single heaviest member of the structure, The main wing spar." The point was that ESD was stronger but it was subject to corrosion. Other countries rejected it and Japan was alone in using it, rightly as it turned out, because they realised that aircraft would not last long in a war.



Was that for the wing spar itself, or the spar caps? Spar cap exfoliation is regarded as the big problem with restoring Japanese aircraft - especially Mitsubishi-built machines - for this reason. It infects the Raiden, as we were discussing before in this thread. The wing spars themselves hold up well, but the spar caps (which are cast) corrode quickly into a flaky substance that looks like rotted wood. When it breaks down the internal structure of the wing just falls apart, and the landing gear collapses. But the Germans used a similar alloy as well, though sparingly. I have an original Bf109E instrument panel made of an 'aluminum/magnesium' alloy that shares these attributes. 


Ron Cole


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## FLYBOYJ (Apr 22, 2012)

ColesAircraft said:


> Was that for the wing spar itself, or the spar caps? Spar cap exfoliation is regarded as the big problem with restoring Japanese aircraft - especially Mitsubishi-built machines - for this reason. It infects the Raiden, as we were discussing before in this thread. The wing spars themselves hold up well, but the spar caps (which are cast) corrode quickly into a flaky substance that looks like rotted wood. When it breaks down the internal structure of the wing just falls apart, and the landing gear collapses. But the Germans used a similar alloy as well, though sparingly. I have an original Bf109E instrument panel made of an 'aluminum/magnesium' alloy that shares these attributes.
> 
> 
> Ron Cole



The reason why the German material held up better was because they probably controlled the silicon content better as well as keeping other impurities to a minimum. Other factors such as uniform furnace temps and even quench during heat treating play into this as well.

More than likely it was the spar caps that had the problem as this type of structure would usually be constructed out of a 7075 type material with the web of the spar being made from 2024.


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## drgondog (Apr 23, 2012)

ColesAircraft said:


> Was that for the wing spar itself, or the spar caps? Spar cap exfoliation is regarded as the big problem with restoring Japanese aircraft - especially Mitsubishi-built machines - for this reason. It infects the Raiden, as we were discussing before in this thread. The wing spars themselves hold up well, but the spar caps (which are cast) corrode quickly into a flaky substance that looks like rotted wood. When it breaks down the internal structure of the wing just falls apart, and the landing gear collapses. But the Germans used a similar alloy as well, though sparingly. I have an original Bf109E instrument panel made of an 'aluminum/magnesium' alloy that shares these attributes.
> 
> 
> Ron Cole



The Wing Spas (fore and aft) are extruded, not cap and shear web rivet assemblies...


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## GregP (Apr 23, 2012)

Hi Ron Cole,

I talked with the Museum staff this past weekend about the Mitsubishi J2M Raiden and said that when I was finished with the Bell YP-59A we are restoring to flight status, I'd like to take a crack at the Raiden. I spoke both to Ed Maloney (our founder) and to the Board Chairman Byian Boyer. Brian said the Raiden was not on the list at this time because the corrosion is bad enough to warrant full disassenbly and inspection ... and the estimated restoration cost would run between $4M and $5M ... and that was not in the cards at this time.

Ed said the engine is pretty much of a basket case, and that installing an American radial would not do because the engine had  really long propeller shaft and American radials don't match that feature ... so we'd pretty much have to resurrect the Japanese raidal, a Mitsubishi MK4R-A Kasei 23a. We MIGHT be able to get Mitsubishi to help ... and maybe not.

So ... probably we'll work on another plane. I'll try for a restoration to flight status of our Ryan Fireball ... we'll see, won't we?

Just FYI.


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## Jenisch (Apr 24, 2012)

Greg, do yous guys that have a Betty? I read it's planned to restore one in the US to flight status.


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## evangilder (Apr 24, 2012)

Greg, I have been waiting for that P-59 to fly and am really looking forward to seeing that. I took some photos of the Fireball on static last year and would like to see that one fly as well. Sounds like you have a lot of work to do on the J2M.


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## FLYBOYJ (Apr 24, 2012)

drgondog said:


> The Wing Spas (fore and aft) are extruded, not cap and shear web rivet assemblies...


Very correct! Have you seen this?

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


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## drgondog (Apr 24, 2012)

Joe - yes - which is why I made the comment..


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## FLYBOYJ (Apr 24, 2012)

drgondog said:


> Joe - yes - which is why I made the comment..


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## GregP (Apr 24, 2012)

Yes, we have a Betty bomber that is displayed in "as found" condition. It is restorable, but would be a 20 year project I think. We have all the main parts. The tail is separated from the fuselage, but we have it all.

As far as the Bell YP-59A goes, we are closing in on it and will dislpay it again this year. I am on a team of 3 guys and there is another team of 1 - 2 guys depending on the weekend. My team built a new sliding canopy from scratch and we are now finishing the windscreen area. If you look closely at the windscreen this year, we have scratch-made the entire thing except for the basic windscreen frame, and we DID make the top center portion of that from scrath, too. The actual front windscreen material is about 2.5 - 3.0 inches thick and we are just completing the sheet metal that surrounds it. The piece that has been on the plane for the last 20 years does not really fit and we decided to make one that does. It is about 90% finished and the shape is correct.

The engines are in it and ready to run, a fire system that was never there in stock form has been fitted, the cockpit is very nearly complete except for the instrument panel (we are waiting on Steve Hinton to make it after he decides what radios and such to install), and we have jacked up the aircraft and have swung the gear ... everything works. When Steve completes the instrument panel, we'll call a fuel truck, fill the tanks and crank it up.

The main things left to complete other than the instrument panel are the wing gap seals (75+% completed), fitting the ailerons (the starboard aileron does not really fit and we may have to make one or make new mounting flanges for the existing aileron), and the last finishing touches on the cockpit windscreen and canopy. Once that is all done, all we have to do is roll it into Fighter Rebuilders and have the A&P's go through the aircraft and systems to ensure we did quality work, fill it with fuel, and do a flight test program. We are about $50,000 short of funds for the fight test program. We
ll probably burn 40% of that on the ground and the rest in flight test. Once done, it joins the list of airworthy planes ready for flight. Likely it will stay in California and fly at our airshow each year as well as perhaps some close airshows, such as March AFB or Edwards AFB. They aren't far and the YP-59A, as short-ranged as it is, can make it to both of those easily.

We only have three engines and, with modern bearings, we think it chould be able to fly for quite awhile since the yearly flight time will be quite low.


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## FLYBOYJ (Apr 24, 2012)

Greg - are you using the original engines?


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## GregP (Apr 24, 2012)

The three XP-59A's used the GE-IA engine with 1200 or so pounds of thrust. It was basically a British Whittle engine made in the USA to English drawings. We are using the next engine, the GE I-16, which was fitted to the the YP-59A's (our plane is the 7th YP-59A and the 10th overall airframe if you count the three XP-59A's) at some point. We THINK the original engines in the YP-59A were GE-IA's and the I-16's were fitted later, so we may have the original engines or not ... the history is hard to dig out entirely. They made 66 airframes: 3 XP-59A's, 13 YP-59A's, 20 P-59A's, and 30 P-59B's. There are about 6 airfrmes left and one is over at March AFB, quite close to us actually

We have the basic data on it, but the original fitment is somehwat of a question. We KNOW it ended up with GE I-16's so maybe yes ... maybe no is the best answer I can give right now. Our I-16's were overhauled in the 1990's and made 1,650 or so pounds of thrust on the test stand at that time.

If the museum agrees, we'd like to put the third I-16 in the Ryan Fireball and get it flying.


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## FLYBOYJ (Apr 24, 2012)

will a stock J33 fit?


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## ColesAircraft (Apr 24, 2012)

GregP said:


> Hi Ron Cole,
> 
> I talked with the Museum staff this past weekend about the Mitsubishi J2M Raiden and said that when I was finished with the Bell YP-59A we are restoring to flight status, I'd like to take a crack at the Raiden. I spoke both to Ed Maloney (our founder) and to the Board Chairman Byian Boyer. Brian said the Raiden was not on the list at this time because the corrosion is bad enough to warrant full disassenbly and inspection ... and the estimated restoration cost would run between $4M and $5M ... and that was not in the cards at this time.
> 
> ...



Thanks for that information, and taking the matter up at PoF. I've known Ed for decades - he was a Charter member of my JII Clearinghouse back in the '80s - but lost touch years ago. 

I've heard a lot about the Raiden from folks there over the years, like Steve Hinton, and pretty much heard the same story. I understand that there has to be a commercial element in the decisions made by the board regarding what gets financed and what doesn't, which makes possible a lot of restorations and preservations that would otherwise never happen - so I'm not critical of it. But there is probably no way the Raiden could be made airworthy again, and if it were done it would likely be at the expense of much of its original equipment. What makes the Raiden such a charm is that she's so original. Ed had to replace the wingtip light covers, some of the canopy plex, tires, and fabric covering - but otherwise this aircraft is as flown in 1945 by the Japanese Navy. I could have hit someone with a spray can in '87 for over-painting the cockpit - but much of the original colors are still there. It was amazing to poke my head behind the pilot's seat to view the inside of the fuselage, and see the original factory stenciling. 

I do think something short of a restoration needs to be done, though; something practical that doesn't cost a fortune but maintains the aircraft's displayability. The landing gear will go one day - at the very least. I work for a Japanese model kit company that is producing a new kit of the Raiden. Their CEO is a wonderful man who buys a lot of WW2 aircraft items from me as well. Maybe I could speak with him about it. I communicate with him regularly and I'll be seeing him in person this August. 

Please feel free to contact me if this strikes a chord. 


Ron Cole


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## GregP (Apr 24, 2012)

Joe, the GE I-16 was later designated as the J-31 and it fits. I don't think the J-33 would fit because the I-16 is 40 inches in diameter and weighs 750 pounds. The J-33 is about 1,800 pounds in weight and I believe it is too big to fit. However, if you have or know if a stock J-33, let me know and I'll pass on the info to Steve Hinton! We definitely have planes that use the J-33!

If you know where a couple of Derewnt 5's are that would be cool! We have a Gloster Meteor ... but no engines ...

Ron, if yiou can find some sponsor for the Raiden, that would be great! I'm sure we'd love to restore it ... the main issue is cost ... and we'd have to get help from Mitsubishi for the engine and maybe the spars and longerons.


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## davparlr (Apr 24, 2012)

I am not an expert here, all I have is opinion. But first I must say that statements AND challenges make for much better understandings. There are many bona fide experts on various aircraft from various countries and all have been questioned by fellow members to the benefit of all. We also have non bona fide experts here. Do not think a question is a personal challenge but rather a request for supporting data.

My opinion is that the Zero is indeed an amazing and beautiful aircraft. It was a bit slow but could really turn and in the early part of the war fighting was still maneuvering and energy management (speed and altitude) fighting concept was poorly, if at all, understood. Also, in 1939, how many aircraft had armor or self sealing tanks? In fact, at the start of 1942, I don’t think the F4F-3 had either. Oh, and the range.



> I don't think it's fair to say that this philosophy was imposed upon Japan due to an inability of Japanese industry to manufacture powerful aircraft engines. The Nakajima Sakae that powered the Zero possessed an impressive power to weight ratio (much as their modern automotive counterparts do). In fact when restorers of Zeros today replace the Sakae with the best American-made replacement engines they can find, the performance of the aircraft suffers dramatically. There is simply no non-Japanese radial engine in the world capable of replacing the original - anywhere, by any manufacturer or nation.



I am not sure of your argument here. You seem to be sitting on a tack here I miss the point, to make a pun. Most of the people here respect the technical accomplishment with the Zero and do not subscribe to the trend that Japanese were not advanced in 1939. Indeed, their torpedo planes were the best and their torpedoes would have been the envy of the world if they only knew. And this is only an example. However, I suspect the Sakae engine was state-of-the-art and similar to other engines in this era. I suspect that an R-1830 mounted with similar accessories would most likely perform similarly. This doesn’t mean that the Sakae was any less impressive.



> The Navy pilots resented that the Army planners hadn't placed more emphasis on range, which left the Navy to fight alone in many circumstances.



This is an interesting statement. Aren’t most Navy pilots, flying off carriers, are there because land based planes cannot reach the target? I would expect they would be use to it. Also, I cannot imagine US Navy pilots admitting they needed the Army pilots for anything. I am not saying you are wrong, it is just strange. 



> The Japanese would have built P-40s??? Sakai expressed contempt for the P-40, as did most Japanese pilots who met them in combat. The Japanese Army actually operated a small unit of captured P-40s they obtained intact from the Philippines, but it was a very short lived experiment. I think it's a beautiful plane, but it wasn't an aircraft, or the embodiment of a concept, that the Japanese wanted to emulate.



I agree with your statement. However, I suspect, that since the P-40B was faster than the Zero and the F4F, and would out dive the zero, and was easier to maneuver than the zero at high speeds, that the main reason for the disdain of the Japanese was due to inexperience, and/or improper techniques of the AAF pilots confronted early in the war. The US Navy pilots would have had more time and more experience and performed much better in their F4Fs. Also, early in the war, Japanese pilots were very good.



> The Sakae series of radials were amazing pieces of technology in terms of their weight in relation to their power output.


It was basically state of the art, so why is that amazing? Was it because it was made by the Japanese? I would say it is impressive, but not amazing.

.


> Thus . . . today it's essentially irreplaceable and the performance of Zeros equipped with lesser (heavier) powerplants see their performance suffer.


How? Since it is admitted that max performance would not be featured then what would be missed, roll rate? Nah. Turn rate? Nah. Climb? Maybe a bit, maybe not. Acceleration? A bit. However the aircraft would still have nice power to weight ratio and unless compared side by side, would probably not be noticed. And finding a mechanic and parts would be a lot easier.


> Now, it may be that the "suffered dramatically" opinion that originated with Nobuo Harada took into consideration fuel consumption - something that obviously would not play any role in an air show hop.


Is there data on fuel consumption in say lbs fuel/hp/hr?



> It's also worth noting, since we're invoking pilot perspectives, that Japanese pilots during WW2 strongly preferred the lighter and less powerful A6M2-21 to any other later variant. They were coveted by units and their best pilots as their numbers dwindled. I've never heard similar claims from Luftwaffe pilots regarding the 'Emil'.


I have heard that some preferred the F to the heavier G. Also, some Navy pilots preferred the lighter F4F-3 to the -4 and some pilots preferred the lighter P-51B to the –D.



> Every Zero owner I know in the world goes to extreme lengths to try to find and restore an original Sakae for reasons other than originality - it's a requirement to make a Zero fly like a Zero!



I don’t think they would ever see it unless they maxed it out, which you said they wouldn’
t do. Also, a 1962 Corvette with the original 327 engine is far more valuable that nice 62 with a hotter 350. 



> It was the first aircraft in the world, it is believed, to have incorporated its duraluminum skin as a structural member. Before that, aircraft were structurally designed on paper to withstand certain forces, then covered to be aerodynamic - but that's how far the designers went to keep the Zero light. It doesn't suffer added weight well, in any form.



The Northrop Alpha, which flew in 1930, used stressed-skin design and its wing design was later used on the DC-2/3. I do not think the Junkers J.1 was a stressed-skin design but rather a metal frame with a metal skin, but not stressed.



> that the West was taking something from them that it had no right to take when it painted their airplanes - usually flaming at the guns of a P-40 - or restored a Zero for primarily Western air shows.



This is a common complaint by all non-US aficionados. I don’t know the answer. I guess most of the customers are Americans. Too bad, especially on the “Dogfight” show. 



Jim said:


> 3) Japanese used combat flaps in their later fighters apparently with good results. However no other nation used them . Do you have any explanation?


Some planes may have a “dogfight” setting on their flaps but any pilot could use them if they know what they were doing. Some reports I have heard tell of P-51 pilots lowering flaps in a turning fight.


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## davparlr (Apr 24, 2012)

GregP said:


> Joe, the GE I-16 was later designated as the J-31 and it fits. I don't think the J-33 would fit because the I-16 is 40 inches in diameter and weighs 750 pounds. The J-33 is about 1,800 pounds in weight and I believe it is too big to fit. However, if you have or know if a stock J-33, let me know and I'll pass on the info to Steve Hinton! We definitely have planes that use the J-33!
> 
> If you know where a couple of Derewnt 5's are that would be cool! We have a Gloster Meteor ... but no engines ...
> 
> Ron, if yiou can find some sponsor for the Raiden, that would be great! I'm sure we'd love to restore it ... the main issue is cost ... and we'd have to get help from Mitsubishi for the engine and maybe the spars and longerons.



Doesn't the J-33 fill up the fuselage of a T-33? I think it is way too big.


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## GregP (Apr 25, 2012)

Yup, pretty much fills it up. And is way fun to fly.


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## drgondog (Apr 25, 2012)

FLYBOYJ said:


>



I wasn't jabbing your comment Joe. A lot of ships used cap and shear web for bulkheads and spars - I went though the entire package to look at the design approach and found it sound and conventional by standards of 40-60's with respect to low/medium speed a/c.

What was somewhat novel in the early 40's was dimpling and countersinking skins for flush rivets in regions where airflow/boundary layer properties were crucial - some examples that come to mind include the 109 and 51 wings and nose (IIRC for the 109). I didn't really look at the Hamp report closely enough for that approach to leading edge on the wings.

Also the use of aluminum skins as shear panels should be obvious to Japanese engineers - as the approach was introduced in the 30's and once again serves very well except when a.) conventional methods don't work for either ultra performance or b.) when combining high performance/low labor such as chem milled or composites structural approach.

I still scratch my head when I hear comments regarding low quality of Japanese engineering. They designed to the mission set by the Japanese Army and Navy and could have matched anything we produced had they changed the mission and had the raw materials for critical parts.


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## davparlr (Apr 25, 2012)

GregP said:


> Yup, pretty much fills it up. And is way fun to fly.



An AF bud of mine flew AT-33s in gunnery training back in early 70s (he was going to OV-10s). He said one had to be careful not to get the castering nosewheel cocked. Also, with its wing tip tanks, it liked to continue to roll once started. Apparently there was line painted over the nose with a string attached to aid in gunnery alignment. Sometimes its the simple things that work. I would imagine that huge centrifugal compressor would take a bit of time to spool up. He also said the instruments seemed to be scattered all over the place with no rhyme nor reason. I would have liked to have flown one just for the history aspects, but I am glad I got to train in the T-38.

I am still planning on coming to see you and tour your facilities. However, with grandkids involved in sports on Saturdays, it tough fitting it in.


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## FLYBOYJ (Apr 25, 2012)

drgondog said:


> I wasn't jabbing your comment Joe.


No worries Bill, I was just being a bit goofy (nothing new).


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## GregP (Apr 25, 2012)

Hi davparlr,

You are certainly welcome out any time. I am there on Saturdays in the restoration hangar.

Time is a luxury and I am either lucky or unlucky depending on your definition in that I am alone, so my time is for whatever I want it to be for. I choose to restore old warbirds on Saturdays. Anyway, if you can fit it in, just ask for Greg in the restoration hangar any Satuday except to the weekend after next ... our airshow is that weekend and we'll all be working the airshow. I'll be taking parking fees in the RV parking area. The view from there is great, so at least I won't miss the show!

Due to federal budget cutbakcs we don't have any military participation this year, but our heritage flight will include a private F-4 Phantom! Looking forward to that one! Old Double Ugly is back for an encore! I hope he plugs in afterburbner and at least does a spirited climbout at the end!

Mwanhile, most of the show will be WWII warbirds along with Sean Tucker and Rob Harrison. The Horsemen will fly again this year and their mounts will be our two P-51's with Steve Hinton in the middle in our P-38!


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## ColesAircraft (Apr 25, 2012)

davparlr wrote: "It was basically state of the art, so why is that amazing? Was it because it was made by the Japanese? I would say it is impressive, but not amazing."

If I wrote that the P-51 was "amazing" would I be taken to task for it?


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## davparlr (Apr 25, 2012)

ColesAircraft said:


> davparlr wrote: "It was basically state of the art, so why is that amazing? Was it because it was made by the Japanese? I would say it is impressive, but not amazing."
> 
> If I wrote that the P-51 was "amazing" would I be taken to task for it?



If you would say that the P-51s ability to fly 600 miles, fight the enemy competitively over their homeland and then fly 600 mile home is amazing, I would not take you to task for that. If you said that the P-51 was an amazing dogfighter, I would. It was a good one but was not significantly better than the other fighters and was not amazing. By the way, I would not take you to task if you made the same amazing statement about the Zero's ability to fly long distance and fight competitively. There were few aircraft that could approach this capability.

From an engine standpoint, I think the P&W R2800-57 engine, with the ability to provide 2800 hp flat rated up to 33k was amazing. The Sakae was a good engine but not significantly lighter or smaller or more powerful or more efficient than contemporary engines.


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## FLYBOYJ (Apr 25, 2012)

drgondog said:


> I still scratch my head when I hear comments regarding low quality of Japanese engineering. They designed to the mission set by the Japanese Army and Navy and could have matched anything we produced had they changed the mission and had the raw materials for critical parts.


You nailed it Bill. They gave "the customer" exactly what they asked for.


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## ColesAircraft (Apr 25, 2012)

davparlr said:


> If you would say that the P-51s ability to fly 600 miles, fight the enemy competitively over their homeland and then fly 600 mile home is amazing, I would not take you to task for that. If you said that the P-51 was an amazing dogfighter, I would. It was a good one but was not significantly better than the other fighters and was not amazing. By the way, I would not take you to task if you made the same amazing statement about the Zero's ability to fly long distance and fight competitively. There were few aircraft that could approach this capability.
> 
> From an engine standpoint, I think the P&W R2800-57 engine, with the ability to provide 2800 hp flat rated up to 33k was amazing. The Sakae was a good engine but not significantly lighter or smaller or more powerful or more efficient than contemporary engines.



I'm saying that we're splitting hairs over my invocation of an adjective.


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## Jenisch (Apr 25, 2012)

drgondog said:


> They designed to the mission set by the Japanese Army and Navy and could have matched anything we produced had they changed the mission and had the raw materials for critical parts.


 
Yes, and actually they had the raw materials initially, this was a problem only later. 

One pre war example of excellent product the IJA didn't accepted was the Ki-12: Nakajima Ki-12 - Wikipedia, the free encyclopedia

One late war example, also from the Army, was the Ki-87: Nakajima Ki-87 - Wikipedia, the free encyclopedia

Notorius about the Ki-87:

_A further variant, the Ki-87-II, powered by a 3,000 hp Nakajima Ha.217 (Ha.46) engine and with the turbo-supercharger in the same position as the P-47 Thunderbolt, never went further than the drawing board._

The Ki-87 prototype achived 697 km/h. Since IJA didn't included boost setting, the aircraft was probably faster. Now imaginate such aircraft with the 3000 hp engine, high octane fuel and good materials - certainly a match to any design in the world.


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## tyrodtom (Apr 25, 2012)

That 697km/h would have to be a projected top speed, not actual. The same article says it only had 5 test flights, and never retracted it's landing gear.


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## GregP (Apr 25, 2012)

I'm thinking of an amazingly impressive airplane ... but I won't identify it due to the liklihood of being adjectivally mugged. Just making a joke ... not being snobnoxious.


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## davparlr (Apr 27, 2012)

ColesAircraft said:


> I'm saying that we're splitting hairs over my invocation of an adjective.


 
I'm sure this is true. To me, for something to be amazing, I have to have my jaw drop and say to myself "how does it do that?" When I read about some of the long Zero missions it does that, when looking at the Sakae stats it does not. It just looks typical. Just a personal opinion.


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## cherry blossom (May 9, 2012)

cherry blossom said:


> The story of “Corky” Meyer seeing the Pratt Whitney logo with an eagle and "Quality Reliability" seems to be true. Similarly the picture at 01 three dollar bill G W Bush « Voices from Russia has the words “Federal Reserve Note”. However, I do not believe that the Nakajima Sakae has a close relationship with any Pratt Whitney engine. Apart from little details like having different bores and strokes, there is the point that all the valves are driven from in front in the Sakae while P&W two row radials drove the valves of the back row from behind.
> ....



Help! I am confused and fear that I have mislead you. I said that the valves of the Sakae were driven from in front. However, the thread on Japanese engines contained a post by Aurum http://www.ww2aircraft.net/forum/engines/data-base-japanese-aircraft-engines-19466-8.html#post881086 and replies by Shinpachi that suggested that the valves of rear cylinders of the Sakae were driven from the back. You can find pictures which show this including Planes of Fame Air Museum - 3989c | Flickr - Photo Sharing! from Planes of Fame, File:Nakajima Sakae.jpg - Wikipedia, the free encyclopedia and http://www.preservedaxisaircraft.com/Japan/Engines/Ha35MOF.jpg. Unfortunately, there is also a photograph from Prima Air Museum Pima Air Museum - Nakajima Sakae (Prosperity) which clearly shows the valves driven from the front (and which I had previously believed). Thus either the Prima photograph is mislabelled or the Sakae design evolved with the early models having all valves driven from in front and the later versions for the A6M5 having the rear valves driven from behind. Can anyone reduce my level of confusion?


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## GregP (May 10, 2012)

I'll look at our Zero this weekend and let you know. It has a Sakae 21 engine.


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## war eagle (May 11, 2012)

The answer to jenisch,s question is not fully answered by a blinding of aviation science you have to look at the prevailing situation that presented itself to the japanese military and its airforces in the early stages of hostilities.In October 1937 its opening spec requirements were unprecedented manouverability,a top speed higher than any existing monoplane fighter (310 mph),a fast climb rate (9800 feet in 3.5 mins).These hastily revised changes came as a result of combat reports from china which showed up the deficiences of its predecesser the A5M "CLAUDE" itself only a few months into combat service.The price that had to be paid to get within these strict guidelines due to the lack of a suitably powerful engine was a severe pairing down of what the military somewhat naively considered non essential weight ie all toughened glass,all pilot protection,no self sealing fuel tanks,no engine protection i suppose they thought if they produced the fastest,nimblist,fastest climbing aircraft available then the only planes being hit would be the enemies.The problem with that theory of course is that air supremecy is only fleeting against big industrialised nations with unlimited raw material resources which the US is.The japanese domination of the pacific skies was never going to prevail for long and as better fighters came into the fray the zero soon became outclassed and by mid 43 the gulf in performance was massive and by the time the zero was given an engine that allowed all the features foolishly omitted in late 39 to be included the japanese imperial land and carrier based airforces were all but irrepairably destroyed and were a shadow of the force that took off for pearl harbour in late 41.


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## Vincenzo (May 12, 2012)

also if Zero become outclassed soon, in mid '43 most of USAAF fighters in japanese theaters were P-39 and P-40.


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## FLYBOYJ (May 12, 2012)

Vincenzo said:


> also if Zero become outclassed soon, in mid '43 most of USAAF fighters in japanese theaters were P-39 and P-40.


But they were being used less and less in an air-to-air combat role. By mid 1943 the P-38 was the dominant USAAF air-to-air fighter. 

•The 39th FS, of the 35th FG, received P-38's in late summer 1942.
•The 9th FS, of the 49th FG, in January, 1943.
•The 80th FS, of the 8th FG, also in January, 1943.
•It wasn't until mid-1944 that the 475th FG, an all-Lightning outfit, was activated.

I think you'll find that by early 1943 the P-39 was harldy used in an air-to-air capacity by the USAAF


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## Vincenzo (May 12, 2012)

Flyboy i've not the right file on this pc but in mid' 43 all USAAF had around 76 operational fighter group of this 14 had P-38 (and we knewn that his was used also in MTO) around 6 used also P-38 and 37 used P-3940 so probably the 3940 were used also in air to air at time


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## FLYBOYJ (May 12, 2012)

Vincenzo said:


> Flyboy i've not the right file on this pc but in mid' 43 all USAAF had around 76 operational fighter group of this 14 had P-38 (and we knewn that his was used also in MTO) around 6 used also P-38 and 37 used P-3940 so probably the *3940 were used also in air to air at time*


Probably based on local operations but in the larger picture, the P-38 was the primary air to air fighter. Examine the major campaings During the summer of 1943. 115 P-38Gs were assigned to the 5th AF and eventually saw their way into the 475th FG. The P-40 still saw service well into 1944 but I think the P-39 and P-400s starting going away by mid 1943 when the 80th FG was moved to from Port Moresby, New Guinea to Mareeba, Queensland, Australia. This unit has been operating in New Guinea since Jul 42.

By Mid 1943 I believe the USAAF and the RAAF started to replace their P-39s with newer or different types (I believe the RAAF replaced their P-39s with the Vukte Vengence)


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## GregP (May 12, 2012)

OK, I looked at the Sakae 21 engine in our Zero. The rods for the front row come out of the engihe case from the front and push the valve rocker arms from the front side. I did not try to look at the back row.

Hope that answeres your question.


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## Vincenzo (May 14, 2012)

back to mid'43 usaaf fighter v/s japanese
july '43
alaska 40 P-38, 126 P-3940 (28 others)
cbi 23 P-38, 201 P-40
pto 0 P-38, 264 P-3940 (23 others)
feto 211 P-38, 471 P-3940 (114 P-47, 6 others)

(others include NF and others day fighters, i'm curious what others day fighters?)


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## FLYBOYJ (May 14, 2012)

Vincenzo said:


> back to mid'43 usaaf fighter v/s japanese
> july '43
> alaska 40 P-38, 126 P-3940 (28 others)
> cbi 23 P-38, 201 P-40
> ...



Don't know your sources for that, but that has to be in error. PTO "0" P-38s?


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## drgondog (May 14, 2012)

The 39th FS of the 35th FG had P-38s in October 42 ---->November 1943, then P-47s for a five months then P51s in mid 1945. The 40th and 41st had P-40s until late 1943 then same pattern as 39th FS.

The 9th FS of 49th had P-38s from February 1943 to November 1943 and got P-47s ------> then all P-38 in mid -1944

The 475th started combat ops w/P-38s in August 1943

Source - Frank Olynyk "Stars and Bars" - squadron historie


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## Vincenzo (May 14, 2012)

FLYBOYJ said:


> Don't know your sources for that, but that has to be in error. PTO "0" P-38s?



the source it is the usaaf statistical digest tables 92, 93, 94 and 95, 
the numbers 0 is right, probably pto give confusion maybe poa is more clear for you?
feto is the theater with most of combat, 35th, 49th and 475th were all in feto


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## FLYBOYJ (May 14, 2012)

Vincenzo said:


> the source it is the usaaf statistical digest tables 92, 93, 94 and 95,
> the numbers 0 is right, probably pto give confusion maybe poa is more clear for you?
> feto is the theater with most of combat, 35th, 49th and 475th were all in feto



That makes sense..


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