Ideal Weight distribution

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Grumpy Cynic
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It appears that this material has been available for the better part of a decade - so why haven't I heard of it before and why is the engineering related data apparently so hard to find?

Seems like it might have some applications for us if treated the same as Kevlar with respect to H2O migration?
 

davidjgall

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It appears that this material has been available for the better part of a decade - so why haven't I heard of it before and why is the engineering related data apparently so hard to find?

Seems like it might have some applications for us if treated the same as Kevlar with respect to H2O migration?
The engineering data is free for the asking from the weaver/manufacturer. It's water migration properties are similar to glass.

From the weaver: "The [1650 denier] BioMid yarn used in this fabric has a breaking strength of 12.5 Kgf (27.5 lbf), which is higher than most E-glass yarns typically used to make a fabric of similar weight." The elongation at break is 4.5%. The density is 1.5, as opposed to glass at a density of 2.54 (BioMid weight is ~60% the weight of glass, on par with aramid fiber). The fiber is 11 micron continuous, untwisted filament of highly crystalline cellulose, 900 threads to make the 1650 denier yarn. The material is thermally stable to 360° C. "The specific stiffness of BioMid in laminates exceeds the stiffness performance of glass." "The specific properties of BioMid laminates are often higher than those made with glass fiber." "Made entirely of certified sustainable wood by-products which do not use pesticides, require extraordinary irrigation or compete with food crops." It is not abrasive like glass, sands more easily and is easier on tooling and processing equipment. And it is biodegradable.

Since it is 100% cellulose I would suggest that it is probably non-toxic and hypoallergenic, but that's just my speculation. This particular fabric is 0.017" thick per lam so fewer lams may be needed in a particular application, and it should exhibit machining characteristics superior to glass if one were to choose, for example, to use a CNC router to cut parts from a sheet of cured composite or sandwich panel.

Here's a cowl being laid up using three layers of BioMid topped by a layer of 3 oz. glass. The one-off mold (mould) is covered with packing tape (conveniently supplied by the USPS) as a release base that provides a visual indicator of the color and clarity of the BioMid/epoxy layups. The 3 oz. glass was added as a veil to reduce the amount of filler needed to fill the weave on the exterior surface of this one-off part. Compare with glass/epoxy.

IMG_0982 (Edited)(1).JPG
As I said before, I have limited quantities available if you want a sample.

Did I mention that it is actually cheaper than glass? Yeah, that too.
 
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Lendo

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D, Sounds too good to be true, but if it's cellulose based, it may absorb more Resin than Glass or Carbon. The product may be lighter but the finished product may be heavier. What is Crystalline Cellulose and how stiff is it to Carbon?
George
 

pictsidhe

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Really?

I thought you would need some weight. Wing loading and all that. Otherwise your plane would be tossed around by the slightest breeze, like a tissue in a tornado.
With zero weight, it would only need enough wing to carry the payload. So you'd still have wing loading.
If you had zero payload, it would all be rather pointless...
 

Aerowerx

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With zero weight, it would only need enough wing to carry the payload. So you'd still have wing loading.
If you had zero payload, it would all be rather pointless...
I thought this thread was initially about weight distribution, not wing loading. Maybe the ideal weight of the airframe and engine would be zero, but in order to fly you still need some mass from the payload.
 

davidjgall

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D, Sounds too good to be true, but if it's cellulose based, it may absorb more Resin than Glass or Carbon. The product may be lighter but the finished product may be heavier. What is Crystalline Cellulose and how stiff is it to Carbon?
George
BioMid fiber is a crystalline cellulose fiber. It is not the hollow tubules of cellulose that a tree naturally grows; rather, it is an 11 micron solid fiber of a material that is "insoluble in water, ethanol, ether and dilute mineral acids." (https://pubchem.ncbi.nlm.nih.gov/compound/cellulose) It does not "absorb more resin" than glass. The finished product weight is determined by the rule of mixtures, just the same as any other fiber/resin matrix composite.

From Wikipedia: "Cellulose was used to produce the first successful thermoplastic polymer, celluloid, by Hyatt Manufacturing Company in 1870. Production of rayon ("artificial silk") from cellulose began in the 1890s and cellophane was invented in 1912."

I don't ever imagine celluloid, rayon, or cellophane as being in any way absorbent, why would pure crystalline cellulose fiber exhibit any different characteristic? We have a preconceived notion about cellulose because it is the primary ingredient in paper, but that use-case presents abundant opportunity for capillary capture of liquids due to its physical structure and other non-cellulose ingredients used as binding agents, not due to the cellulose material itself.

(https://en.wikipedia.org/wiki/Cellulose)

The stiffness of a part made from BioMid cloth and epoxy is comparable to that of one made from fiberglass cloth and epoxy.
 

12notes

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I've looked up BioMid, have searched the sites listed under "Availability" on their website, and have found no reference to it under any of the distributors websites. Can't find a vendor for the fabric easily through Google, but can see an article that in 2013, sales of the fiber "exceeded expectations". After 7 years on the market, I would hope that the fabric would be available somewhere easy to find.

Who is/was your supplier? Will they sell to anyone smaller than a medium sized government? Is it still being made in fabric form?

They should probably think about getting a new marketing department, it shouldn't be this difficult to find.
 

pictsidhe

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I emailed BioMid this afternoon asking for a datasheet and who sells it. If they respond, I may play with it.
 

davidjgall

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Who is/was your supplier? Will they sell to anyone smaller than a medium sized government? Is it still being made in fabric form?

They should probably think about getting a new marketing department, it shouldn't be this difficult to find.
I buy individual 100 yd. rolls wholesale directly from Absecon Mills. I can supply you with a smaller quantity if you’d like to try some.
 

Norman

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Would a real aircraft (no scale model) be able to fly if its wings were made out of paper?
Maybe, but, the strength to weight ratio of a composite material is strongly tied to the length of the fibers and how tightly those fibers a bound together in the matrix. Paper is composed of very short fibers with little or no matrix. This is not a recipe for a strong and stiff material so to make strong structures out of it you'll have to use a lot which means that structures made from paper will be heavy. Adding a matrix (glue) will improve the strength and stiffness quite a bit but it's still not anywhere close to the most similar composite, which is wood. Think about it, paper is simply chopped up wood that was floated in water and lifted out with a screen to make a thin sheet. What used to be long fibers are now short and the once continuous matrix has been broken up into a bunch disconnected chunks. Restoring the matrix by saturating the paper with glue only dose part (a small fraction actually) of the job of restoring the strength of the original wood because the fibers are short and not all oriented in the same direction (in a wooden part all the fibers are parallel and extend the the whole length of the board). In long parts like spars it's essential to have long fibers (preferably the entire length of the spar) because the matrix is not as good as the fibers in either tension or compression.

You could make skins out of paper if you saturate it with glue to form a matrix but it still wouldn't be as strong or stiff as the same thickness of plywood so paper skins would have to be thicker than wooden skins for a given rib spacing.
 
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