Whats the deal with Soviet Wing design?

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tyrodtom said:
I'm sorry I'm just a simple mechanic and bodyman, when someone can't be bothered to even get the correct cylinder count on a engine, I wonder what other details might be too unimportant for him to get right.
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The Warburg Knight was an East German 3 cylinder two stroke, they sold a few in UK, eventually killed off by emission regs.
 

Have you seen how a spitfire wing is constructed?
 

How do you think stampings helped or are you guessing? Unless you're building an aircraft by hand, each have their difficulties in assembling. Assembly jigs help greatly but one must develop a process to fit all the pieces in the jig and assemble them in an order to you could shoot all the rivets and get all components to match engineering drawings.
 

Over the years [decades really ] I've read of the use of presses in spitfire production a number of times, so no, I'm not guessing though I have little direct detail. If you have simple two dimensional shapes and relatively thin aluminium sheet it could be simply wrapped around the stringers/ribs or jig, held on by temporary rivet "Cleveland" pegs and riveted.

For the more difficult compound shape a press could be used for mass production rather than a craftsmen beating them or rolling them to shape on something like an "English Whee". These are likely to be 'stretch forming presses' whereby the sheet was gripped and pulled over a male die. A more conventional press such as where a male die forces a sheet into a female die could also have been used, I've seen that process used to produce DC-3 nose cones. In that case the male dies was simply blocks to rubber cut and layed up to approximate the shape of the nose cap. The stretch forming press was the more common process.

One a press is involved the spitfire wing is no longer harder to produce than an ordinary wing, in fact it is easier to produce. The only cost was the initial tooling cost: you need to first of all order a press, develop a die, then experiment and modify a little. Then you are able to make large sections of thick skinned material that is of consistent dimensions and likely more rivet and fabrication free.

I suspect this is the actual stretch forming press (machine) used to make Spitfire wing leading edges at Castle Bromwich, it looks long enough:
View: https://www.youtube.com/watch?v=Tp6age-sn2c
Of the cowling of a CFM-56 (boeing 737)
View: https://www.youtube.com/watch?v=Kh4MBHyHAtg
This is the hard labour intense craftsmens way of doing it:
View: https://www.youtube.com/watch?v=IGElSHzm0q8

As aircraft skinds become thicker and more 'monocoque' presses became more and more important. I've read in a "Wings" article on the B-26 Marauder that the skin over the wing box that interconnected to two wings was about a 72 inch or so long single piece that was stretch pressed. It kept cracking until an 'old hand' recognised the problem and added a little grease to let the metal move a little as it stretched.

The B-29 Super fortress had rather thick skins and they had to be formed with presses.

KiwiBiggles said:
Oh no, we've moved on to Spitfire wings. I fear the dreaded one-spar two-spar argument is not far away.
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They fabricated ((pressed) the D section leading edge and likely mated it with the main spar first.

http://spitfiresite.com/wp-content/uploads/2012/07/39-39-7558001446_ec9e89b851_k.jpg
http://spitfiresite.com/wp-content/uploads/2012/07/41-41-7558010984_37d4748325_k.jpg

The construction techniques used on the leading edge of the Spitfire wings were very advanced, they involved techniques that became normal only 8-10 years latter at the dawn of the jet age.

The point is, once you've set up the tooling and presses it likely cost no more to produce than an more ordinary wing. The only production excuse for not doing this is that you can't get presses or are scared they'll get bombed.
 

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Spitfire wings were not stretch-formed. They were done the old fashioned way.

I don't believe stretch-forming tools were available in WWII ... but I also haven't absolutely verified that timeframe.

Quenching was not in vogue until Aluminum was well along in the 1950s, as far as I know. Basically you form the 2024-O ALuminum, heat it to about 900°F for 25 minutes (varies with thickness and volume of Aluminum), and quench it in water within 10 seconds of removal from the oven. If you don't, you have to do it all over again in order to get 2024-T3. You cannot handle it with cloth gloves or they just flame away instantly and burn the crap out of you. I use duckbill pliers and just drop them into the water with the Aluminum.

900°F is nothing to trifle with.

If I am not mistaken, Spitfire wings were formed with O Aluminum and, when formed, were heat treated and then final-shaped

By the way ... GREAT videos! I love 'em.
 
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pbehn said:
The Warburg Knight was an East German 3 cylinder two stroke, they sold a few in UK, eventually killed off by emission regs.
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I've had my nose under the bonnet of both a Trabant and a Wartburg around 1993 when visiting sister in law relatives. To be frank I didn't take much of an interest in the cylinder count as they were already on the way out, almost immediately replaced by second hand German and French cars (car yards on every corner, personnel mobillity a freedom we don't even notice) but remember now that it was the Wartburg that had the 3rd cylinder. The Wartburg had received greater engineering effort but was still primitive. People had to wait years to get one. At the time, with the expose of STASSI files it had been revealed to the German villagers that two 'boys' had gained their apprenticeships as refrigeration mechanics by betraying some other boys who had made mild sarcastic jokes about competence of the political authorities. The betrayal was recorded, created a black mark for others but earned points for the scabs. When it came to good jobs or university access the file was pulled and consulted. That's what communism leads to. You have little freedom or choice to decide what to buy, you can't choose who to work for in your chosen field. Political intrigue rather than work, competency or meting demand is the way to advance. They could do reasonably well in some areas when there was a clear goal, such as making a better tank or fighter plane or creating a spectacular programme to say launch a satellite.
 
So you read this - did you also read that the component has to be held in place with a jig?!?!? Cleveland peg?!?! Don't you mean a Cleco???

OK - what you describe fabricates one component - it has to be attached to the rest of the assembly. How you supposed that done?!?!?
"likely more rivet and fabrication free" are you sure about this?!?!
Koopernic said:
I suspect this is the actual stretch forming press (machine) used to make Spitfire wing leading edges at Castle Bromwich, it looks long enough:
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You "SUSPECT?

Again, youre giving a great narrative of single component fabricationand nothing about ASSEMBLY.
Koopernic said:
The point is, once you've set up the tooling and presses it likely cost no more to produce than an more ordinary wing. The only production excuse for not doing this is that you can't get presses or are scared they'll get bombed.
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I could agree with that statement but again you have totally missed the point - weather individual components are stretched formed or formed with an English wheel they have to be assembled in a jig, end of story. You keep saying "ordinary wing," please tell us what you mean by that? If you were assembling a swept wing with compound curves, is that an "ordinary wing? Is an F4U or Stuka's wing ordinary? You're putting out information here based on what you're reading in books not realizing that some of us ACTUALLY built a few aircraft over the years [decades really ], so please spare us the tutorials unless you've been there your self and really know how to use a rivet gun!!!!
 
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The Lavotchkin's fighters used NACA 230 series profile (until switch to the laminar flow wing from La-9 on), the MiG used the Clak YH. Planform was probably a design choice of the design bureau.
 
GregP said:
Spitfire wings were not stretch-formed. They were done the old fashioned way.

By the way ... GREAT videos! I love 'em.
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I've given a link with a picture of a stretching machine above, here is the link again:
http://spitfiresite.com/2012/07/cas...ory-photos.html/37-37-7557991922_b5a00aa490_k
The caption to this photo says:
"Castle Bromwich Aeroplane Factory. 150-ton stretching machine at Block 'F'. " So clearly they were using the process
(and on the B-26) though it was considered an advanced technique.
Block F is shown in the picture below:


It has both a "press room" and 24 "Wheeling machines" next to the tool room so that doesn't clear anything up at all except that there was a 150 ton pulling machine and also wheeling machines which by one account made the wing fillets?

" F Block - At the West end of the block was another steel stores whilst at the East end was another Tool Room and Pattern Shop. The Tool Room was actually on the North side with the Pattern Shop on the South Side. In the middle on the North side was the Press section, and on the South side of the centre were 24 "wheeling" machines that produced the "Hockey Sticks" used to seal the wings to the fuselage. These machines had to work 24 hours a day, 7 days a week. "



It could have made Lancaster parts, or perhaps parts of the fuselage. The wing fillet was also a compound curve. Perhaps both systems of production were used. With the Spitfire having a wing span of 36 feet I think that pulling press, which looks about 3 man lengths long could handle an entire leading edge. Having said that, the photographs of wings in my previous post seem to be of universal "C" type wings since they have openings for up to 2 x Hispano guns and the openings were separately fabricated. The C type was in part developed to simplify mass production.




The reason I use the word suspect is that although there is definitely a 150 ton stretching press at Castle Bromwich there is no caption to indicate what it was used for. Also although I recall reading the comment about parts of the elliptical wing being pressed the Author may have been wrong and I can't at present recollect the book/author to confirm, I'll get there. Heinkel also had problems with his metal built elliptical wings and the He 112 prototypes were of a lumpy appearance as they had no dies to use.

By "ordinary wing" I mean a standard tapered wing which lacks significant compound curve. My argument is that with a press the labour content used on subsequent assembly would be no worse than for a straight wings while the pressing operation is not labour intensive in itself. Thicker wings skins with fewer stringers and stiffeners members may need less rivets or make it easier to countersink. (and I'm repeating something I read) was pretty good from a mass production point of view.

Yes I did mean Cleco, I've seen them called Cleveland Clamps in a very old book.
 
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And again that's you're opinion - it's quite obvious you're making these assumption on what you read or by looking at pictures. The amount of rivets used or number of stringers have NOTHING to do with wing thickness!!! What type of wing structure are you talking about? Will it be conventionally built or feature corrugation sub skin? How long will it be? Will it be made from milled wing planks and held in place with hi locks? Is the wing for a fighter, bomber or transport aircraft????

I've built aircraft as well as sub assemblies and worked at Lockheed, Boeing and BAE to name a few and I could tell you don't have a clue what you're talking so please don't try to school us with what you read in books, some of us have actually "been there/ done that."
 
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I am surprised everyone still believes the Factory cover story for Spitfire construction. Spitfires were actually carved from a single Oak Tree that had been blessed by a Druid, a Bishop and a Virgin riding a Unicorn (Virgins are always in very short supply but luckily the Govt Unicorn breeding programme was coming along nicely by 1939). When a pilot got his wings he went to Saville Row and was measured for his Spitfire the Tailor would ask "Which side does Sir dress his Oxygen Tube" then a group of woodland Elves would carve the aircraft to suit. When it was finished the Elven Queen would tell the new pilot "This Plane is to rule them all you must fly it to Mordor but you only have 5 minutes of fuel for combat before you must return or the Orc 109s will shoot you down"
 
Why all this talk about metal forming when all three aircraft in the original question had wooden wing construction, or a combination of wood and metal ?

Two of the 3 could hardly be termed substandard aircraft by anyone's yardstick, so they can hardly be held up as good examples of the failures of the communist system.
 
Koopernic said:
It could have made Lancaster parts, or perhaps parts of the fuselage.
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Again you're guessing!!!!

Most if not all WW2 aircraft wings were assembled in some kind of jig - if they weren't when you started riveting everything together you would get structure that twisted and warped. Very simple wings like the Spit and -109 were built in jigs that allowed the placement of a front and rear spar. Jig "details" aligned ribs to their proper location in reference to engineering drawings. Once attached the skin is installed in such a manner so you don't rivet yourself in a corner. Blind rivets were used in inaccessible areas but their application was limited because they for the most part cannot take high tension loads. Explosive rivets were also used for inaccessible areas as well.



In the case with a P-38 wing being assembled, the L/E is facing down and the structure is assembled vertically. The jig will "build in" any twist or compound curve. Wings are still built this way, here's a link to a Seversky product, possibly a P-35 being assembled.

SeverskyWingBuild.jpg Photo by VNSPEC22 | Photobucket

This is a Spitfire Repair Jig



And a B-24 wing being assembled



Some wings were assembled with a corrugated skin attached to the ribs then an outer skin riveted to the "hats" of the corrugations. This provided great strength to the wings.



A later process involved taking very rigid slabs of aluminum (7075) and milling down the slabs so the inside of the skin had a series of uniformed "risers" that attached to ribs. For the most part many modern aircraft wings are built this way and are held together with hi-loks. This is a link that shows a P-3 wing.

http://www.navair.navy.mil/img/uploads/11_12F.jpg

Stretch forming was done during the fabrication state and was limited during WW2 because aluminum alloying and heat treatment techniques were being developed on the fly. Annealed aluminum could be formed quickly but had to be heat treated after the forming process unless the stretching of the aluminum allowed it to be "cold worked" to the point where it carried enough strength for its intended purpose. English wheels were used for hand fabrication but required a lot of time and skill to turn out a good product. Drop hammers were the easiest way to form parts with compound curves but were limited in as dies did wear out and could be expensive to make (let alone the cost of the press).



This isn't everything but explains the basic process WITHOUT GUESSING or assuming things while sitting at your lounge chair!!!! So when you hear someone say that one wing is easier to build than another (or perhaps maybe, assuming, it could have, possibly) have them state the facts!!!!!
 
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I believe you forgot two very important details:
First, at the village workshop, each new Spitfire being fashioned required a fresh supply of dirt from Hastings cast on the floor.

Secondly, before each pilot was led through the doors to receive his Spitfire, he was required to kiss the pommel of Excalibur and exclaim "For King and Country!"
 
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