A6M5 Model 52 Zero

[GregP]

Good joke on me Hiromachi,

At the Planes of Fame we have a Mitsubishi A6M5 Model 52 Reisen (flyable but undergoing overhaul at this time), a Yokosuka D4Y-3 Suisei (static but can start and taxi), a genuine Yokosuka MXY7 Ohka (nobody wants to fly this one ...), a Mitsubishi J2M3 Raiden (restorable), a crashed Mistubishi G4M Bomber (Restorable), a full complement of Arisaka rifles, some genuine uniforms and helmets, a real Mitsubishi J8M1 Shusui (probably restorable, but I would not want to fly the original engine) together with the rocket engine, the landing gear trolley, wheels, and tires, a Jpanese torpedo (unknown type but I can find out) ... and we used to have a flyable Nakajima Ki-84 Hayate that is now in Japan in a museum.

Our founder, Ed Maloney (still alive and kicking) has done a lot to keep the Japanese heritage of WWII aircraft alive and well in the USA and, hopefully, in Japan. Every December we have a Japanese day and usually fly the A6M5 together with a presentation program on it. Sometimes it is the D4Y. Our grandfathers may have had a war, but our generation and younger didn't.

I'd really love to see a Ki-44 fly and would appreciate working on it to help. Ditto the German and Italian fighters, bombers, etc. One of ny favorites is a Fieseler Storch that is original ... but the Argus AS-10 needs to be overhauled to runnign condition. Not a fighter, but would be wonderful to see fly. Find a Macchi 202/205, Fiat G.55, or Regianne 2005 and we will be happy to restore it!

Perhaps you could come see it all sometime with Shinpachi. I'd love to show both you around and let you cut and rivet some aluminum together ... maybe you'd go back and restore something! Maybe a real Ki-44.

Best regards, - Greg

 

[Hiromachi]

Good joke on me Hiromachi,

Well, I also didnt know it is a joke till Shinpachi posted the date. So I joked on you ... involuntarily. Now that is a nice intellectual combination.

a flyable Nakajima Ki-84 Hayate that is now in Japan in a museum.

With a cut-off wings ... someoen should tell those guys from museum that one doesn't make such things on only flyable machine ...

Perhaps you could come see it all sometime with Shinpachi. I'd love to show both you around and let you cut and rivet some aluminum together ... maybe you'd go back and restore something! Maybe a real Ki-44.

I would like to visit US, really. But for Poles there is still a Visa problem and to be honest trip for a student is quite expensive. But I hope I will visit US to see all those planes, maybe something more will be found and restored. And well, it is the only chance to see J8M, taste Texas BBQ and visit interesting places.

Yokosuka MXY7 Ohka (nobody wants to fly this one ...)

If nobody wants I would take Okha for a ride, it would be the last one but unforgettable


BTW.
I have no idea if you knew, but Smithsonian's National Air and Space Museum has very large parts of Aichi B7A Ryusei.
The National Air and Space Museum's Ryusei is believed to be the only remaining example in the world. The U.S. Navy recovered from the Japanese home islands and shipped it to the United States for evaluation. Unfortunately, nothing of the bomber's operational history is known. The Smithsonian Institution accepted the airplane in 1963 and placed it in storage. It awaits restoration at the Paul Garber Facility in Suitland, Maryland. The B7A2 proved a useful resource during the restoration of another Aichi product, the M6A1 Seiran (see NASM collection). Lacking drawings and other information, the restoration staff used the GRACE on several occasions to investigate how Aichi built certain features. Some parts were also identical and, if missing or damaged on the Seiran, could be copied from the Ryusei.

So they used it to restore other plane and now is in terrible conditions :

They also have Kikka as I remember, but from what I understood it is not going to be restored. At least they dont want :

 

[Shinpachi]

Thanks for your kind offer, Greg.
Please tell my best regards to Mr Ed Maloney.
He is one of the most historic US citizens who contributed research and study of Japanese aircraft.

 

[GregP]

Will do, Shinpachi. And thanks for the interesting infomation, Hiromachi.

The B7A would be a welcome addition to the Japanese WWII aircraft around the world, as would the Kikka. Unfortunately the NASM usually doesn't sell or trade their aircraft, and I can't think of a time when they sent out resotration to another group. There are strange requiremnents when you deal with a givernment. We had to jump through a lot of hoops to examine the cockpit canopy on the Bell P-59 at March Air Force Base when we were making the unit for our YP-59A. They have some very strange rules.

 

[Hiromachi]

I suspect that, I tried to contact Smithsonian to get some data, only data about Ryusei. But well, they are not helpful, nor polite. That is sad, especially if they have a planes they dont even plane to restore in next decade or more, and someone else could do that ...

But well, that's how the world looks. In Poland we can't restore to flyable condition only existing PZL P.11c in Cracow. It has deeply damaged wing and they lack data.
But they have restored PZL P.37 Łoś. We just need to search for positives.

 

[razor1uk]

Lots of lovely pics, info, history and Greg P's insights - thanks for the reply earlier, sorry for the long wait re-replying back.

 

[GregP]

Hi Hiromachi,

About the wing ... they can do some forensic restoration. That is, drill out the rivets, separate the structure, measure the pieces and go from there to build a new one. That's what we had to do with our Yokosuka D4Y Judy dive bomber ... start with the pieces and use them for patterns. Most were in bad shape and had to be straightened and made flat to make a pattern.

I'd bet the P.11c CAN be restored with some effort and some skill. The D4Y we restored was in 4 pieces and the entire nose was missing when we got it. The cockpit was crushed flat and the belly was crushed flat. The tail was missing. We started with pieces and then used drawings to get probable measurements for the tail, and made a structure similar to German Heinkel structure from which the D4Y was developed.

There were no real plans for that, either.

If there is someone over in Poland who wants to pursue that, they can contact the Planes of Fame at Chino, California and speak with Steve Hinton or Ed Maloney. Perhaps something can be worked out, particularly if the restoration is to be static and not airworthy.

PZL is still in business, aren't they? As PZL-Meilec at least? Perhaps the P.11 plans were lost in the war?

From the pictures I see on the internet, the P.11c in the museum is in good enough shape to be assessed for internal structure type and configuration. Plans can be made from it. But if they are not going to fly it, perhaps it isn't worth the time, expense and risk? But they COULD restore it to runnable static condition so it could be started and taxied ... assuming the fuselage is strong enough to handle an engine run.

I have them but don't know where they are right now ... but I'll see if I can dig up some shots of the D4Y before and during restoration. The shape it was in when we started was quite bad. The P.11c is in MUCH better shape to start with.

 

[Hiromachi]

About the wing ... they can do some forensic restoration. That is, drill out the rivets, separate the structure, measure the pieces and go from there to build a new one. That's what we had to do with our Yokosuka D4Y Judy dive bomber ... start with the pieces and use them for patterns. Most were in bad shape and had to be straightened and made flat to make a pattern.

Nah they are too careful and ... lazy I think, or simply lack resources. It's a public museum. They dont want to try as they are afraid of loosing the only one existing.

PZL is still in business, aren't they? As PZL-Meilec at least? Perhaps the P.11 plans were lost in the war?

Yes, that is also the problem. A lot of materials have been lost or than just burnt by Germans through the War.

And this is the result of long-way building of PZL-37. They used as many original parts as possible :

View: https://www.youtube.com/watch?v=Ano4z1vwX7E

 

[GregP]

That's a nice aircraft! I'd love to see that one fly!

Best of luck with your projects.

We have a PZL TS-11 Iskra and it looks like a lot of fun to fly. We don;t fly it, but it was airworthy when we got it.

 

[Hiromachi]

From what I remember this bomber was quite ... agile, if that can be said for a bomber. It had not only quite large control surfaces, but also flaps and slots. Control and stability were nice and there were a few examples when P-37 went into "turnfight" with Bf-110 or Bf-109.
Sounds more like legend, but still plane was quite advanced. The only problems it really had was lack of protection and quite bad defensive armament.


Greg, is it possible if you could make more pictures on Raiden flaps ? I was quite interested how far they could be deployed, and not only for Take-off or Landing, but also Combat.

That was another part, how truly maneuverable Raiden was ? For Zero pilots it was brick, but same was for Ki-44 when they were tested by Ki-27 pilots ... in reality Ki-44 still possessed decent turn time, in monograph about it I found data of turn time below 20 seconds.
Maybe Raiden also wasn't so bad ? Especially as Japanese put a lot of efforts to make effective flaps.

 

[GregP]

I can certainly get pics of the flaps, and will ask if John Maloney knows the flap extension limits. I am not sure if we have a manual on it or not since it hasn't been restored.

I believe it was not very maneuverable when compared with the A6M5, as you said, but was fairly maneuverable when compared with Allied fighters. In my opinion the propeller blades are too short and suffer from aspect ratio issues. It would probably have benefitted from longer prop blades, but was flown with the propeller as designed by everyone who ever flew it.

I'd love to see it restored, too. In unrestored condition it looks pretty good as-is!

 

[Hiromachi]

Ohh, well it is obvious it is not close to Zero. Zero was turned to be maneuverable, I remember one of your posts when you said that J. Horikoshi helped in restoring A6M5 mod 52 or rather you had a discussion, he said it was build to being as agile as possible.
So it is obvious for me that Zeros or Ki-43 are more maneuverable as obviously they were built in that purpose.

What I was interested is the comparison to Allied or Soviet planes.

In my opinion the propeller blades are too short and suffer from aspect ratio issues. It would probably have benefitted from longer prop blades, but was flown with the propeller as designed by everyone who ever flew it.

As I remember it was already complained the handling of the Raiden on the ground, by quick looking on it ... if the propeller would be bigger ... than landing gear would also have to be bigger. And we would have something like a N1K1-J Shiden.
But only Jiro Horikoshi knows why did they choose this one instead of something else ...

I'd love to see it restored, too. In unrestored condition it looks pretty good as-is!

I would love also, it is one of the more specific planes. Maybe not so beautiful as Ki-44 for me or Ki-27 (I'm rather Army branch fan) but very special

if we have a manual

If you would actually have it, would it be a pilots handbook with performance data or rather technical book with data for the mechanics ?

I have N1K2-J Handbook for Mechanics, which I hoped to help me with figuring the Shiden Kai performance but it had only technical data, like areas or placement of various equipment. As I know now, there is only one real Pilots Manual for N1K2-J, and it is in Shiden Kai museum. They keep it somehow very secret, no pictures allowed, even single data from it is for me unknown.
Shame, I would visit museum but again, Japan is far from Europe.

 

[GregP]

Actually I believe the essence of what J. Horikoshi said was that they wanted the performance of the most modern aircraft but only had a medium power engine to work with. He never expected more than about 1,100 HP from the Sakae engine. In order to get the required performance levels something had to be left out, and it was armor, self-sealing tanks, and the like ... in order to maintain performance levels.

Given his own preferences he would have desiogned these things in, but he did not have the luxury of 1,500 + HP engines from which to choose; he was told to use the Nakajima Sakae engine.

I think Curtiss-Wright did the same sort of thing with the CW-21. They had a small engine and wanted BIG performance, so they left out a lot of things ... and the aircraft was never really combat ready as a result. The A6M5 WAS, and that is a testament to Jiro Horikoshi's talent that he could make it work when others could not do so. I believe if he had updated the Zero design with a Homare or other similar much more poweful radial he could have either maintained performance and added in the formerly left-out items or could have improved performance and STILL left out armor, self-sealing tanks, etc ... but probably could not have both added in the items left out and still improved on performance simultaneously.

In the end, I think he did pretty well with 1,130 HP.

 

[GregP]

Found an old video clip on the Caifornia Air Museum that became the Planes of Fame. In this clip you can see the Nakajima Ki-84 we used to own and fly. It is now in an air museum in Japan.


View: https://www.youtube.com/watch?v=8waXqQoBri4

Enjoy!

 

[Hiromachi]

Found an old video clip on the Caifornia Air Museum that became the Planes of Fame. In this clip you can see the Nakajima Ki-84 we used to own and fly. It is now in an air museum in Japan.

That is a nice finding. Thank you Greg

The A6M5 WAS, and that is a testament to Jiro Horikoshi's talent that he could make it work when others could not do so. I believe if he had updated the Zero design with a Homare or other similar much more poweful radial he could have either maintained performance and added in the formerly left-out items or could have improved performance and STILL left out armor, self-sealing tanks, etc ... but probably could not have both added in the items left out and still improved on performance simultaneously.

More powerful engine, especially like 18 cylinder would have to lead to a big design changes due to weight increase. But I was thinking of Kinsei 51, bigger than Sakae and had also higher fuel consumption but available quite early.

Also the main problem is still there - high speed maneuvers. It was a major issue, and even N1K2-J had problem due to fabric covered control surfaces, that above certain speeds the roll rate would drastically drop, the elevator would not respond so quickly. Zero was known for this problems.
But than again, how in this case performed J2M3 Raiden ? It was supposed to be high speed plane though ...

 

[GregP]

Well the J2M-5/6 was about a 370 mph aircraft at best height (407 mph WER) and the wing loading was down around 32.8 pounds per square foot (160.1 kg per square meter) at normal takeoff weight, so it might have been less maneuverable than the Zero, but was in the ballpark for a decently maneuverable aircraft anywhere else, at least given a reasonable airfoil ... which I am assuming it had but don't know for sure. It probably cruised between 200 and 300 mpoh and had an initial climb rate of 4,600 feet per minute (1.402 meters per minute), so it wasn't a slug in anybody's book. Range was short without drop tanks, but could stretch to 1,100 miles with drop tanks.

I've never seen whether that climb rate was normal or WER. The data are sketchy at best.

The performance seems like a slightly faster Hellcat, though the climb rate was at least 1/3 better, with better armament. Seems like a tough customer to me.

I don't know that there is a good writeup on high speed maneuverability anywhere in the world. With four 20 mm cannons in the later variants it hit hard and was among the best Japan had at intercepting the B-29. They just never had enough of them with only 621 built. The aircraft performance website has speed, climb, and range charts, but nothing on roll rate of general maneuverability, so we are left with speculation there.

There is some mention of criticism of the visibility by the pilots but, having stuck my head in the cockpit, the visibility was pretty good for a radial engine aircraft. If there is one place where it might suffer, that would be the rear view in common with all planes lacking a bubble canopy. It might have been less than wonderful compared with the visibility in an A6M.

The effective aspect ratio was 5.8 (span squared divided by wing area), so it probably rolled rather well. With the wing loading it was probably a decent turner if the airfoil was good. I've never seen an airfoil for it in print but assume it was decent given the designer's history.

To me, if the engine issues were solved, it seems like a good interceptor, but of limited use on other missions due to short range on internal fuel alone.

 

[Hiromachi]

Well the J2M-5/6 was about a 370 mph aircraft at best height (407 mph WER) and the wing loading was down around 32.8 pounds per square foot (160.1 kg per square meter) at normal takeoff weight, so it might have been less maneuverable than the Zero, but was in the ballpark for a decently maneuverable aircraft anywhere else, at least given a reasonable airfoil ... which I am assuming it had but don't know for sure. It probably cruised between 200 and 300 mpoh and had an initial climb rate of 4,600 feet per minute (1.402 meters per minute), so it wasn't a slug in anybody's book.

TAIC gives for Jack-11 speed of 350 mph on SL and 407 mph on 17 400 feet altitude, climb rate at SL of 4600 feet per minute.

For Jack-21 it is speed of 359 mph on SL and 417 mph on 16 600 feet altitude, climb rate at SL of 4825 feet per minute.

Those are very nice numbers, especially if we keep in mind that Zeros were used in 70% of sorties, than such plane would be a very big surprise to any Hellcat or even Corsair.

The effective aspect ratio was 5.8 (span squared divided by wing area), so it probably rolled rather well. With the wing loading it was probably a decent turner if the airfoil was good. I've never seen an airfoil for it in print but assume it was decent given the designer's history.

There was in the internet some fine comparison between Hellcat and J2M3 in case of maneuverability and other aspects, have you seen it maybe ?

 

[GregP]

I saw that comparion somewhere, maybe from in here, but have lost the URL for it. If anyone has it, please post it again. Thanks! When I read it I was favorably impresed with the Raiden, though in a one-on-one with a Hellcat I think the better pilot would make the difference.

The structure of the A6M is a very GOOD one, but the materials are thin, meaning it can take much less battle damage before something critical fails. Some places the skin os .025"!

I have seen the internal structure of both the Hellcat and the J2M and am impressed with the J2M, but do not know the thickness of the metal. If it is heavyer gauge, then it well might take as much battle damage as a Hellcat and possibly more. If the skin is thin, it would be more like the A6M. Now that I'm curious about it, I'll take a few measurements on skin in the next couple of weeks and come back to this.

When we tested the J2M after the war, we found it to be some 25 mph faster than the TAIC numbers, but we were also using much better fuel than the Japanese were during the war. So maybe the TAIC numbers are pretty representative of wartime J2M's.

I have an Allied pdf report on it and it has favorable things to say, giving the Raiden good marks for stability, stalling characteristics, comfort, takeoff and landing qualities, good performance and great maneuver flaps. It gets knocked down for brakes and rudder braking action, heavy ailerons and lack of maneuverability at high speeds, short range, and low mechanical reliability.

To me, heavy ailerons and lack of maneuverability at high speeds are solvable, as is the mechanical reliability issue. Hevy ailerons CAN be solved. The time were the times, but disk brakes weren't very far away, and the brakes could also have been fixed, even if with better drum units. The Raiden wasn't the only potentially great fighter with bad brakes. The list is long and distinguished.

Given a bit of dedicated development, I think the Raiden could have been one of the very good ones from the war. As it is, it came close, but had enough teething problems to make it a late-bloomer. It was in protracted development at the same time the designer was working on the Reppu and other projects, too. Perhaps Mitsubishi should have let him finish the Raiden before adding other assignments, and Mitsubishi themselves should have made the Kasei engine reliable much quicker or should have used something else, even if it came from Nakajima. The war and the country were at stake and company self interest was not a thing that should have been tolerated. But that is hindsight from many years after the fact ... and we know all companies on both sides did much the same during the war, so perhaps that criticism is unwarranted.

 

[Hiromachi]

View attachment F6F-5 vs J2M3-b_opt (1).pdf

Here it is.

When we tested the J2M after the war, we found it to be some 25 mph faster than the TAIC numbers, but we were also using much better fuel than the Japanese were during the war. So maybe the TAIC numbers are pretty representative of wartime J2M's.

Please tell me more about this. I was always so curious about US made tests. They are so mysterious in many cases, one got TAIC data but they are estimated in many cases, sometimes show higher than possible to obtain performance and sometimes are fairly proper.

So You have tested J2M3 mod 21 after war. Can you tell me more about that ? Not only performance but also feeling. That is something one can't get from books, how the plane really feels and handles in the air is unique thing ...

I have an Allied pdf report on it and it has favorable things to say, giving the Raiden good marks for stability, stalling characteristics, comfort, takeoff and landing qualities, good performance and great maneuver flaps. It gets knocked down for brakes and rudder braking action, heavy ailerons and lack of maneuverability at high speeds, short range, and low mechanical reliability.

Could you be so kind and share it with me ?

The war and the country were at stake and company self interest was not a thing that should have been tolerated. But that is hindsight from many years after the fact ... and we know all companies on both sides did much the same during the war, so perhaps that criticism is unwarranted.

It was too old competition to be simply stopped. Even the production inside of companies was split between Army and Navy ...
Putting aside old differences would change a lot but I dont think it was possible ...

 

[GregP]

First, thank you for the pdf! I appreciate it.

Here is a link to the AircraftPrformance tests of the Jam: http://www.wwiiaircraftperformance.org/japan/Jack-11-105A.pdf

I don't know where the my pdf file is on the web, but if you PM me your email, I'll send it along in an email attachment.

The J2M was a good aircraft with some flaws, so it pretty much is similar to a lot of other good aircraft also with flaws.
I happen to like it, but turning it into a winner is another "what if." The king of the "what if" is the Ta-152, a great plane on paper that did almost nothing in the real world of war (8 - 10 victories against 2 - 4 losses). But on paper it was one of the very best. All the "what ifs" in the world can't change the real war record and in the real world, it is an interesting footnote ... sort of like the Raiden. But at least the Raiden made a mark against B-29's, though I have seen that written ... I have also never seen a list of supposed kills attributed to the Raiden. But, few other Japanese fighters could claim B-29's in any significant number; they couldn't catch them!