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Composite wing ribs

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ultralights

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This is a composite wing of a European light aircraft manufacturer. You can see that it has carbon sandwich ribs and glass sandwich ribs. The carbon ribs support flaps and ailerons and are carbon tape bonding to wing skin and spar. The glass fiber/foam ribs are bonding without tape, only glue (micro?). What do you think about this construction system?

000213.jpg
 

ultralajt

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URL: ATEC 321 FAETA
URL: ATEC - Technical details
I always like to see the whole thing, not just an segment taken out isolated, prior making conclusions... :nervous:
The Wing
is a reinforced shell of a carbon-fibre sandwich. It is tapered backswept wing of an angle of 5,5° with SM 701 airfoil along all the span. The wing spar is made of laminated hard beech saturated with synthetic resin.
So, wooden spar in a composite wing? Hybrid?! :gig: I see such design in one of the TEST gliders... with mixed feelings...
It is like old man married with young women... one will die or weaken or get tired of another early, while other will then die without getting chance to show its full potential.. :) :roll:

I would like to hear a designer explanation why he choose such design and maybe I will then accept that without doubts...

When skin of the composite wing is designed so thin, that it needs support against buckling when wing bends (lifting and torsional loads), then of course some ribs should be incorporated in the design, hence these "false" ribs in the wing you show us. It seems that carbon ribs are structural ones, where loads from hardware is introduced and spread into the rest of the structure (spar and skin).

Usually a 3-6mm thick wing skin sandwich, with outer laminate strong enough not to penetrate with a sharp pointed object is sufficient to handle loads resulted in the air. Almost all modern sailplanes dont use any ribs inside, except root rib with lift or torsion pins for transfer loads between wing and fuselage.

I think, that couple of false ribs can be incorporated in to your wing if you feel that will prevent upper surface buckling at extreme wing bending, without adding excessive weight. But a static load test to destruction will show you if they are necessarry or not.

Regards!

Mitja
 
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BJC

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This is a composite wing of a European light aircraft manufacturer. You can see that it has carbon sandwich ribs and glass sandwich ribs. The carbon ribs support flaps and ailerons and are carbon tape bonding to wing skin and spar. The glass fiber/foam ribs are bonding without tape, only glue (micro?). What do you think about this construction system?

View attachment 47440
Why the tank within the composite wing rather than an integral tank?


BJC
 

henryk

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krakow,poland
Can you point to some internal wing photos?

Thanks,


BJC
https://www.youtube.com/watch?v=jV5AvOtwnFA

-old video,now Bogumil Beres is not alive \2016.02.03\!

http://www.plar.pl/NewsImg/beres.jpg

-I cant finde the pics...from memory=short,circa 2m central spar,
inserted into wing pockets...

http://www.homebuiltairplanes.com/forums/attachments/composites/7040d1278448388-alternative-take-spar-rib-wing-design-lrimg_0305.jpg

http://www.homebuiltairplanes.com/forums/attachments/composites/7041d1278448388-alternative-take-spar-rib-wing-design-lrimg_0307.jpg

http://stara.gorpol.pl/lotnictwo/diana/4/diana2-3.html

-multilayer skin,specific configuration...

\2* 46 kg wings, empty weight 182 kg\
 
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RPM314

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So, wooden spar in a composite wing? Hybrid?! :gig: I see such design in one of the TEST gliders... with mixed feelings...
It is like old man married with young women... one will die or weaken or get tired of another early, while other will then die without getting chance to show its full potential.. :) :roll:
Well, it seems like the spar itself is not composite, just a regular wood spar with some weatherproofing. The ribs and skins are composites, but they don't take wing bending loads. If it was like, carbon spar caps and a wood shear web then it would be weird and structurally inefficient. But as is I think it's only weird and economically inefficient.
 

ultralights

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I'm not sure that the wing skin is sandwich. There may be a bad translation into English. I think that placed fiberglass/foam ribs because the wing skin is a solid laminate of carbon to control buckling of the skin.
Faeta_3.jpg
 

Battler Britton

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I'm not sure that the wing skin is sandwich. There may be a bad translation into English. I think that placed fiberglass/foam ribs because the wing skin is a solid laminate of carbon to control buckling of the skin.
View attachment 47466
Here is an interresting point to me.
Let's say it is not sandwich, could we imagine that this carbon or glass skin could act as a kind of very strong fabric over a wood structure ( maybe with glass ribs) ?

Not of the economic point of vew, just about interaction bewteen srtong wood spar and light composite skin. In fact, like a KR2 without foam inside?

Thank you, specialist over there , to be kind with that barbarian question...:)
 

BJC

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A historical note:

Myron Jenkins, after building a Sun n Fun and Oshkosh grand champion Glasair III, built a "glass GlaStar." The wing had glass ribs and a core-less glass skin rather than aluminum. The skin deflected very noticeable between the ribs. A
In aerial photos, it looked like an aluminum wing with a too thin skin.

There was a single seat, reverse stagger one of a kind biplane built ca 1960's that was covered with fiberglass. IIRC, the wing interior had wood spars and wood ribs.

Weight and strength, in both cases, would have been different with CF.


BJC
 

Aviator168

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No amount of CF (unless you use too many layers) with no core can prevent buckling between the ribs. Put some core in the wing skin. Just a little, like 1/4 inches, at least in the upper wing skin.
 

WK95

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Twice as heavy as necessary and potentially tricky at the joint to the skin...

Glass ribs don't do a thing with carbon ones next door...
Maybe they went broke buying the carbon. But in all seriousness, why would they do that in the first place?
 

WK95

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I wonder why they only put carbon on a couple of ribs while the rest are just plain foam. What an odd thing to do.
 

Aviator168

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I wonder why they only put carbon on a couple of ribs while the rest are just plain foam. What an odd thing to do.
The carbon ribs are for hardpoint support. The foam FG ribs are there just to retain the shape of the wing. What I don't understand is why FG instead of CF.
 

ultralights

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No amount of CF (unless you use too many layers) with no core can prevent buckling between the ribs. Put some core in the wing skin. Just a little, like 1/4 inches, at least in the upper wing skin.
Typical carbon fiber fabric(0/90) young modulus is 70 Gpa like to Aluminum 72 GPa. You could make a wing with skin and ribs of carbon fiber like a aluminum wing would get the advantage of lighter weight carbon. This is known in the industry as "black aluminum", but not the most efficient way to take advantage of the composite.
 

blane.c

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What do the ribs weigh in comparison to a aluminum rib doing the same job? How do you hold the fabric to them? Seriously I am curious.
 
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