Shenyang FC-31 / J-31 Fighter Demonstrator

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Air Force Brat

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kurutoga said:
The chemicals I was referring to is only applied to the outer surface, before paint/coating.
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You guys are all wet behind the ears, the darker green is a primer for the carbon fiber to protect it from UV radiation, the bright yellow is "ZINC CHROMATE", look it up, its applied over aircraft grade aluminum, after that aluminum has been "ALODINED", or "ACID ETCHED" to remove the factory protective coating that prevents corrosion initially.

The Alodine removes that coating and etches the aluminum so that the zinc chromate will adhere to the surface... if you looked inside the inner aluminum surfaces, many interiors are zinc chromated as well in order to prevent corrosion...

Once they are ready to coat it with the final finish coat or RAM, it will be the grey or darker grey more than likely, that we have seen on the J-20's that are "finished" and not in primer.

so primer does indeed give you a very strong indicator of what material lies beneath!

those carbon fiber bay doors are def "structural" you should do a little independent research on bicycles and race cars,,, many open wheel cars have gone to carbon fiber tubs and "back-bones"!

now go do some research, and further more, if Shenyang didn't have government funding and backing and "tacit approval" you would have never seen a "V2" version,,, let the obvious speak!

are they gonna sell it,,,,, "you bet", somebodies going to buy it, no doubt the Saudi's are interested, as at present they may not get the F-35???
 
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latenlazy

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Air Force Brat said:
You guys are all wet behind the ears, the darker green is a primer for the carbon fiber to protect it from UV radiation, the bright yellow is "ZINC CHROMATE", look it up, its applied over aircraft grade aluminum, after that aluminum has been "ALODINED", or "ACID ETCHED" to remove the factory protective coating that prevents corrosion initially.

The Alodine removes that coating and etches the aluminum so that the zinc chromate will adhere to the surface... if you looked inside the inner aluminum surfaces, many interiors are zinc chromated as well in order to prevent corrosion...

Once they are ready to coat it with the final finish coat or RAM, it will be the grey or darker grey more than likely, that we have seen on the J-20's that are "finished" and not in primer.

so primer does indeed give you a very strong indicator of what material lies beneath!

those carbon fiber bay doors are def "structural" you should do a little independent research on bicycles and race cars,,, many open wheel cars have gone to carbon fiber tubs and "back-bones"!

now go do some research, and further more, if Shenyang didn't have government funding and backing and "tacit approval" you would have never seen a "V2" version,,, let the obvious speak!

are they gonna sell it,,,,, "you bet", somebodies going to buy it, no doubt the Saudi's are interested, as at present they may not get the F-35???
Click to expand...
As I recall, the F-22's skin is mostly composites, and yet early production aircraft mostly used yellow primer (though from what I can gather not strictly carbon fiber). Clearly aluminum isn't the only material that require surface coatings with the colour yellow.


14295_1_.jpg
 
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jobjed

Captain
jobjed said:
The guy said he was driving to work, passed by SAC, and saw 2 pairs of V-tails. He thinks he saw both in yellow primer but it was a very brief glance. There is the possibility that he saw wrong or the other pair of Vs belong to FC-31 v1.0.
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@Deino

The user officially recanted today. The other pair of Vs belong to 1.0, not 2.0 No.2. He took a closer look today and the other V was very clearly trapezoidal and black.
 
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jobjed said:
@Deino

The user officially recanted today. The other pair of Vs belong to 1.0, not 2.0 No.2. He took a closer look today and the other V was very clearly trapezoidal and black.
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That's not recanting, that's "clarifying",,, and that's what we all suspected was likely anyway! you see we're skeptical in nature, there's a reason for that, because if something sounds to good to be true, it probably is.
 
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latenlazy said:
As I recall, the F-22's skin is mostly composites, and yet early production aircraft mostly used yellow primer (though from what I can gather not strictly carbon fiber). Clearly aluminum isn't the only material that require surface coatings with the colour yellow.


14295_1_.jpg
Click to expand...

The F-22 uses a welded up Titanium center fuselage/tub like many race cars, it is very strong, titanium, aluminum, and carbon fiber... there are lots of photos of the last F-22, and that aircraft has many different shades of primer....

remember, and acid etch to remove any oxidation, rinse, and alodine, then zinc chromate the aluminum....the zinc chromate will not last forever, its always best to protect it from UV with a top coat, the same for carbon fiber, that darker green that you see on the FC-31 is to protect the carbon fiber from UV.

Carbon fiber bicycles used to use an aluminum "drop-out" bonded to the carbon fiber to attach the wheels to the bike, this often resulted in corrosion to the aluminum..my bike has a full composite carbon fiber front fork, it is very strong. Carbon fiber is very susceptible to damage however, and once the fibers are cut my fail catastrophically.

So integrity is very important, bonding is important, and I can assure you the Chinese under stand all these processes very well.
 
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siegecrossbow said:
Guess neither PLAAF nor PLANAF is interested for the time being.
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Probably not at the present, my guess is that the J-31/FC-31 was presented as a LO end of the Lo/Hi concept, still a good concept, even though US only has 183 HI end fighters at present, many of which are for test and not combat coded...

The FC-31 will make an excellent Mig-29 competitor, and would likely fly off the ramp as well as the Mig-29K

another possibility is that the FC-31 could be up-sized as was the Hornet into the Super Hornet,,,, that would put it into a similar category as the J-15, able to use those AL-31FNs that are quite functional on the J-20, J-15..

in the meantime, who knows? the WS-13 may well be moving closer to production at some point
 
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taxiya

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Air Force Brat said:
You guys are all wet behind the ears, the darker green is a primer for the carbon fiber to protect it from UV radiation, the bright yellow is "ZINC CHROMATE", look it up, its applied over aircraft grade aluminum, after that aluminum has been "ALODINED", or "ACID ETCHED" to remove the factory protective coating that prevents corrosion initially.

The Alodine removes that coating and etches the aluminum so that the zinc chromate will adhere to the surface... if you looked inside the inner aluminum surfaces, many interiors are zinc chromated as well in order to prevent corrosion...

Once they are ready to coat it with the final finish coat or RAM, it will be the grey or darker grey more than likely, that we have seen on the J-20's that are "finished" and not in primer.

so primer does indeed give you a very strong indicator of what material lies beneath!

those carbon fiber bay doors are def "structural" you should do a little independent research on bicycles and race cars,,, many open wheel cars have gone to carbon fiber tubs and "back-bones"!

now go do some research, and further more, if Shenyang didn't have government funding and backing and "tacit approval" you would have never seen a "V2" version,,, let the obvious speak!

are they gonna sell it,,,,, "you bet", somebodies going to buy it, no doubt the Saudi's are interested, as at present they may not get the F-35???
Click to expand...
I don't fully understand what you are saying. It will be easier for me to understand if you can tell me what the yellow pieces being attached to the wings are?
  1. Are they composite? It should be, because F-35's skin are supposed to be all composite?
  2. Is the yellow color from zinc chromate coating? Coated on the surface of composite (black/gray) sheet?
  3. If they are composite, doesn't it mean that being yellow or green is not indicative of what the underlying material is (metal or composite)? This is what I was trying to say.
1109_HPC_F35_1.jpg;width=560
 
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