Whats the deal with Soviet Wing design?

[GrauGeist]

Greg, isn't there any photos of the PoF Zero that was disassembled and shipped to Japan a few years back?

There might be some shots of the wing detail

 

[Elmas]

Hi Parsifal,

Our Zero is intact and complete ... but undergoing overhaul. If you are interested I can get some pics, but there is no access to the wing interior.

Perhaps the attachment might help you out.

- Greg

The hand made drawings in this article are really a masterpiece.....

 

[tomo pauk]

Don't know whether people are familiar with this gold mine:
LiTOT: Content

 

[Juha]

Hello Greg
re your post #80
Wow!

Juha

 

[FLYBOYJ]

Interesting discussion guys. Id really like to know about the Zeke wing. ive read it was exceptionally lightly constructed, with about half the fasteners of a spitfire,made of a new alloy material, with something called a single spar construction (whatever the hell that is) that made its fabrication difficult. the Zeke was generally regarded as a difficult aircraft to construct. I was hoping someone like greg might illuminate me........

I didn't read all the way through Greg's excellent download but I do know that the Japanese were instrumental in developing 7075 aluminum and I know i read somewhere the Zero had a lot of 7075 in it's construction. As far as it being "difficult" to construct, one would actually have to examine how it was assembled in the jig because once a jig assembly process is established it's really a repetitive process unless there's a situation with getting detail parts to fit correctly - I do know the Japanese has issues with interchangeable parts so that might have played into this.

 

[GregP]

I have some pre-overhaul pics and will get more this coming Saturday so I can post a before and after. The Zero is coming along well and should be flying again in December.

What happened was we sent it over to Japan for 110 months in 2012-2013 and when it came back, it was time for an overhaul. We restored it originally in 1976, so we flew it for 37 years and it was time. Then the airshow season hit together with some critical things to a couple of other warbirds and, before we knew it, the Zero was down for a year. So it is being worked on as you read this and I'll post pics this weekend.

I came across that file on the design analysis of the Hamp about 15 years ago and thought everyone who was interested had it or I'd have posted it much sooner. Attached is another one that some may find interesting. It isn't AC-43-13, but is quite good anyway.

The second one is a Hellcat versus J2M Raiden comparison. We have a J2M-3 at the museum.

View attachment Aircraft_Metal_Structure_Repair.pdf

View attachment F6F-5 vs J2M3-b_opt.pdf

 

[tyrodtom]

I've seen figures on how many man-hours it took to make a Bf-109 in 1940, 42, etc.
Does anyone have such information on the Zero ?

Because my impression is that it would be high.

 

[GregP]

Here's a few Zero pics before the overhaul when it was disassembled:

1. Here's looking into the rear fuselage of the Zero before overhaul. This is an A6M5 Model 52.

Naturally the cables are loose because the rear fuselage is detached from the center section.

2. Here is looking into the cockpit center section when the entire front and rear have been removed. This is before overhaul got to the interior, but you can see we replaced the skin over one the wheel well and a few other places where you can see fresh green primer. The shaft on the left side (actually right side, but backwards) about mid fuselage controls the cowl flaps and there is a small crank that the pilot turns to open or close them.

After this was taken, the entire interior was stripped, repaired as necesssary, primed, and painted. The they started fitting the controls and fixtures back in.

I'll get some more this weekend and you can see the difference between that time and now. These pics were taken in May 2015.

3. Here is a shot of our Nakajima Sakae 31 radial. This aircraft was captured on Saipan in 1944 and was returned to the US for some study. It was placed back in flyable status and was one of the aircraft used at the 1944 Fighter Conference at Pax River, Mayrland. It was the only aircraft of the entire group, as far as I know, that never broke the entire time. The Sakae 31 is running great! It could use some cosmetic spruce-up, but runs quite nicely. Our other Sakae 31 is complete but in parts. That way, we can fix the flying engine if it breaks. So far, it hasn't.

For some reason, it won't let me add any more, even in a new post. Perhaps a bit later. I already uploaded quite a few Mb in 2 threads today and it looks like there is a limit.

 

[BiffF15]

Greg,
Thanks again for sharing!
Biff

 

[Hiromachi]

I didn't read all the way through Greg's excellent download but I do know that the Japanese were instrumental in developing 7075 aluminum and I know i read somewhere the Zero had a lot of 7075 in it's construction.

Peter C. Smith in his latest book Mitsubishi Zero - Japan's Legendary Fighter said it was T-7178 zinc aluminium alloy. Generally speaking I found book quite accurate, so its possible with this author was correct as well. But the best option is looking on the Japanese side of the internet.

 

[GrauGeist]

Not sure how 7178 was used in the A6M, as that particular alloy was developed in the early 1950's, where as 7075 was developed in the mid 1930's specifically for Mitsubishi by Sumitomo...

 

[GregP]

I can say this about Japanese WWII aluminum from personal experience.

When you find it today on a Pacific Island, if it has started to corrode ... the alloying metal has corroded completely away, leaving flaky pure Aluminum that peels away like mica. It has no strength left. We see some of the same with US Aluminum, but it is clearly intergrannular corrosion and usually still has some strength left.

I hear Japanese WWII Aluminum was alloyed with Zinc and ours was with Copper. This doesn't mean Japanese metalurgy was not as good as US metalurgy .... all it means, if the assumption is true, is that Zinc corrodes quicker than Copper does in salt air. Once intergrannular sets in, it will happen eventually ... there is no "rescue" possible for either alloy.

Surprisingly, most of the Aluminum on our A6M5 Mode 52 Zero is original, not all, and has not even come close to starting to corrode yet. We did see SOME corrosion and that metal was replaced in 1976. We also replaced a few things this year so far, but not much in the total aircraft ... a small skin here and there and a few brackets.

We see the same in Corsairs, Hellcats, Spirfires, etc. Some of the original metal is good and some needs to be replaced. More is OK than not OK. Sometimes we make a new panel not because of corrosion, but becaause the panel was creased or bent and making a new one is easier than trying to straighten it. Plus, you KNOW the metal is OK if you make it new.

Sometimes we make a new piece from the next thicker gauge of metal. An example would be the formers in a T-6 cowling. The stock ones are made from 0.040" 2024-T3 ... and people tend to stand on them when they do maintenance. Not surprisingly, the formers tend to bend when "Bubba" is wrenching. We make new formers from 0.050" 2024-T3 and they don't bend anymore with Bubba or without him. They aren't structural, and so arn't "changing the design" ... they just hold the cowling metal pieces on the plane.

We got a Bf 109Erecovered from the bottomn of a lake in Russia some years back. It had been underwater (fresh water) for 48 years. Surprisingly, some of the metal looks like it still might be OK. It might NOT be OK when looked at closely, but some looks like it would clean up and have no corrosion on it. I consider that to be extraordinary. Of course, the Magnesium was gone away completely. But some Aluminum looks pretty decent. Believe it or not, the engine was rebuildable and is being rebuilt at this time.

I'll get some pics of the Bf 109E this weekend, too.

Interesting you should mention Sumitomo, Graugeist. The propeller on our Zero is generally called a Mitsubishi, but was really made by Sumitomo.

 

[parsifal]

greg, remind me never to argue with you about aircraft mechanicals......

 

[FLYBOYJ]

Peter C. Smith in his latest book Mitsubishi Zero - Japan's Legendary Fighter said it was T-7178 zinc aluminium alloy. Generally speaking I found book quite accurate, so its possible with this author was correct as well. But the best option is looking on the Japanese side of the internet.

As mentioned 7178 wasn't around in the late 1930s/ early 1940s IIRC. I think zero construction material is mentioned here.

How To Build a Zero (1945) | From The Archives

 

[gumbyk]

I hear Japanese WWII Aluminum was alloyed with Zinc and ours was with Copper. This doesn't mean Japanese metalurgy was not as good as US metalurgy .... all it means, if the assumption is true, is that Zinc corrodes quicker than Copper does in salt air. Once intergrannular sets in, it will happen eventually ... there is no "rescue" possible for either alloy.

That ties in with the alloy number - 7XXX series alloys are zinc and 2XXX are copper. Interestingly, the Zinc provides a harder alloy than copper.

http://www.esab.ca/ca/en/education/blog/understanding-the-aluminum-alloy-designation-system.cfm

 

[FLYBOYJ]

I can say this about Japanese WWII aluminum from personal experience.

When you find it today on a Pacific Island, if it has started to corrode ... the alloying metal has corroded completely away, leaving flaky pure Aluminum that peels away like mica. It has no strength left. We see some of the same with US Aluminum, but it is clearly intergrannular corrosion and usually still has some strength left.

I hear Japanese WWII Aluminum was alloyed with Zinc and ours was with Copper. This doesn't mean Japanese metalurgy was not as good as US metalurgy .... all it means, if the assumption is true, is that Zinc corrodes quicker than Copper does in salt air. Once intergrannular sets in, it will happen eventually ... there is no "rescue" possible for either alloy.

Greg, you nailed this on the head. 7075's major alloying elements are Zinc and magnesium. It's strong stuff but will turn to dust in the right humid conditions. 2024 (or 24T in WW2 days) has more copper in it, one of the reasons its so malleable, especially in the "O" condition.

I've worked on GA aircraft out of Florida, the Texas gulf coast and Camarillo and seen corrosion attack parts of them and virtually turn them to powder!

 

[GregP]

Hi Joe,

I've seen that, too. When we redstored our Yokosuka D4Y, I saved a piece of longeron that is a graduate study in corrosion.

Makes me angry when we come across an Allison or a Merlin that was left to rot in a field ... and they didn't even leave the spark plugs in and plug the coolant openings. What it means is the inside is junk, needlessly so ... but there may be a few good pieces on it.

Hey Parsifal,

If you don't want to argue about it with anyone, make it FlyboyJ. He does it for a living and I'm a volunteer. Somewhat of a difference there, but I appreciate it anyway. Hope you can get to the Planes of Fame sometime and can see it and maybe take a flight in a warbird. Plenty of aircraft-related things around the area from our museum (Planes of Fame) to Yanks, to Palm Springs, the Lyon museum, San Diego Air and Space museum, Reuben Fleet museum, and lots of warbird operations happening ... most of the time.

All the best. - Greg

 

[Hiromachi]

As mentioned 7178 wasn't around in the late 1930s/ early 1940s IIRC. I think zero construction material is mentioned here.

How To Build a Zero (1945) | From The Archives

Alright, than it seems the author was wrong. I have original Jiro Horikoshi book, Eagles of the Mitsubishi but its only mentioned there that they used ESD, not indicating a specific digit.

Interesting you should mention Sumitomo, Graugeist. The propeller on our Zero is generally called a Mitsubishi, but was really made by Sumitomo.

Sumitomo Metals was biggest manufacturer of the propellers in Japan. It's hard not to find an aircraft that used the Sumitomo propeller Greg.

 

[drgondog]

Again you're going to have to be specific on where you're talking about. I'm not a structural engineer but have done structural repairs based on data developed by an engineer. In laymen's term I've always dealt with engineers dealing with bending, twisting, shear and compression loads.

And Tension...

Sheet metal panels have primary function to transfer loads via shear. Rivets carry the loads individually in shear and the allowable shear load is balanced between the shear stress of the rivet and the point of failure applied to the cross section of the hole in the sheet.

Bending loads and torsion that we have been talking about for the Pe-2 in the empennage are transferred to the Longerons (for bending in the Y and Z axis) as axial tension and compression, the torsional loads are transferred to the Bulkhead - all via the riveted panels.

To visualize placing a vertical load in 'bending' on an "I" beam with upper and lower caps connected by a web ('spar'). One cap is in tension, one is in compression and the loads are transferred via the 'web' in shear.

Stringers, if connected to say bulkheads, can perform as mini-longerons but the primary purpose is to prevent buckling of the shear panels they are riveted to, when bending/torsion is applied to the 'box' or 'cylinder'

 

[parsifal]

Makes me angry when we come across an Allison or a Merlin that was left to rot in a field ... and they didn't even leave the spark plugs in and plug the coolant openings. What it means is the inside is junk, needlessly so ... but there may be a few good pieces on it.

Here i go, but what the heck. I would have thought if you could get the pistons out, you could rebore and re-sleeve the cylinders. New caps in the crank housing, crankshaft re- machined (well a big maybe there) and the valve and seats, should be recoverable if they have carbonisation....and require a reseat, or are they so far gone that nothing remains inside?

Hope you can get to the Planes of Fame sometime and can see it and maybe take a flight in a warbird. Plenty of aircraft-related things around the area from our museum (Planes of Fame) to Yanks, to Palm Springs, the Lyon museum, San Diego Air and Space museum, Reuben Fleet museum, and lots of warbird operations happening ... most of the time.

Something like that would be a dream for me. Maybe in two or three years when i retire......I would love to just sit in something like a P-51 and soak up the smell of gasoline.