Darkaero aircraft

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Deuelly

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I was checking out the Darkaero aircraft yesterday at Oshkosh and decided to check out their website. On the home page of the website it flashes through some pictures, one of them being the internal structure of the wings. I can't figure out what they're thinking with the structure. To me they went overboard with the ribs and are lacking any kind of shear web and spar cap. Can someone with more knowledge than me explain how or if this would work.

http://www.darkaero.com/aircraft

Thanks,

Brandon
 

narfi

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The picture moves very fast, it is hard to see what is going on.
With that many full height stringers, are they all spars and the skin the cap?
 

cheapracer

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Meh, just an eggcrate construction.

Nothing special, maybe not common in wings, but common in many other things.

eggcrate.jpg
 

Deuelly

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I'll add these pictures to help people see what's going on.

In this picture though you're looking at the wing root of one wing.

Screenshot (57).jpg

In the picture below it doesn't look like much structure has been added to connect the two halves. It just seems really week to me at the wing root. I'm trying to figure out how a person would handle the shear and bending at the root in this situation.

Screenshot (59).jpg
 

autoreply

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I was checking out the Darkaero aircraft yesterday at Oshkosh and decided to check out their website. On the home page of the website it flashes through some pictures, one of them being the internal structure of the wings. I can't figure out what they're thinking with the structure. To me they went overboard with the ribs and are lacking any kind of shear web and spar cap. Can someone with more knowledge than me explain how or if this would work.
I share your concern. I can't think of any reason to have that many shear webs for lack of a better word. Same for the ribs in a composite design.
 

fly2kads

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It looks to me like they fell in love with their carbon/aluminum honeycomb panels (advertised elsewhere on their site), and devised a way to use as many of them as possible.
 

Aerowerx

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Not that different from something Orion had several years ago.

Carbon fiber skin with multiple "spars" running span wise, arranged in a W pattern.
 

12notes

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I'm not sure that's a wing. It's really hard to tell scale from the video, that could be the horizontal stabilizer.
 

BoKu

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Not that different from something Orion had several years ago.

Carbon fiber skin with multiple "spars" running span wise, arranged in a W pattern.
Except that the W arrangement actually reacts sectional shear due to lift loads.
 

HJC.Pepper

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It looks to me like they fell in love with their carbon/aluminum honeycomb panels (advertised elsewhere on their site), and devised a way to use as many of them as possible.
I'm quite sure they fell in love with the material
And after much structural analysis used as little as possible.
Strength for weight honeycomb materials are Strong but sheets are generally thin so it's all about how it's used within the structure to get the strength to weight benefits.

It's like making a corrugated cardboard structure they can be made very strong

So it's out if the box thinking

Aitch :ban:
 

cheapracer

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It's like making a corrugated cardboard structure they can be made very strong

So it's out if the box thinking
More like box thinking.

I can see why they did it, but can't see a single advantage, but can see a few disadvantages.

It's not like it's moldless either, clearly there are some major molds happening around it, so why not just mold a single piece corrugated inner as well.
 

Jay Kempf

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Not that different from something Orion had several years ago.

Carbon fiber skin with multiple "spars" running span wise, arranged in a W pattern.
But Orion had that stuff figured out such that there was a bonding cap with enough area between each web at the skin. Not so much with what the OP showed us here.
 

BBerson

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Is this sandwich wing skin or solid carbon skin?
If it is solid carbon skin then the multi-cell web might make sense.
 

dsigned

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I was checking out the Darkaero aircraft yesterday at Oshkosh and decided to check out their website. On the home page of the website it flashes through some pictures, one of them being the internal structure of the wings. I can't figure out what they're thinking with the structure. To me they went overboard with the ribs and are lacking any kind of shear web and spar cap. Can someone with more knowledge than me explain how or if this would work.

http://www.darkaero.com/aircraft

Thanks,

Brandon
First page:
The DarkAero 1 uses a unique structural appoach we call "Hollow Grid." Hollow Grid is an arrangement of CNC cut, carbon fiber and honeycomb sandwich panel ribs and shear webs. All the compression, tension, and torsional loading is carried through the outer skins while the Hollow Grid helps the skin maintain its shape and prevent buckling. This approach results in assemblies that are stronger and significantly lighter when compared to other structural approaches.
Basically (if I'm reading this right), the outer skin is the primary structure and the inner panels are just there for rigidity. Having worked a (very) little with carbon fiber, but being more familiar with its use in high end yacht racing: you don't need interior bracing at all if you make the skin thick enough, and it would still be stronger and weigh a fraction of what an aluminum wing would.
 

Hot Wings

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you don't need interior bracing at all if you make the skin thick
That is a big IF. While weight is important for racing yachts it's even more important for aircraft. To put this in nautical terms imagine how thick the skin of this structure would have to be to have the equivalent strength and stiffness:

Surfboard.jpg
 
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