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Old 09-06-2018, 11:51 AM   #86 (permalink)
kach22i
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March 6, 2018
First Ride: Endura Drag2Zero skinsuits tailored for aero efficiency
https://www.velonews.com/2018/03/bik...iciency_458722


Quote:
DERBY, England (VN) — Most of cycling’s aerodynamic glamor is in frame and wheel design. But Endura’s designers recognize that a rider’s body and clothing induces significant drag — up to 80 percent of a rider’s wind resistance......................

SST is only applied to the sleeves and flanks for a reason. These are two areas on the rider’s body where laminar separation — or the separation of air from a surface — can cause problems by creating a low-pressure pocket on the trailing edge of a shape. It’s the same issue that airfoil frame tube shapes address.

The silicone chevrons help reduce laminar separation by creating tiny vortices of air. Airflow then adheres to that surface longer and flows more smoothly around it. That means the air separates from the surface later, shrinking the drag-inducing low-pressure air pocket behind the rider.
The butt cheeks or at least the hips are where the silicone chevrons would be most effective, right?



I don't see any there.

Related, further in the article they mention a material used in the helmet called "Koroyd" said to be superior to Styrofoam, but no comparison to Monopan or other honeycomb materials.

Upon watching the video in the link, I suspect the inner and outer tubes can move independently to a degree based on a frictional resistance, and it is only the outer tubes that get thermally bonded together. It's not clear to me yet at this time as it's a short video with no words.

Has anyone in the forum heard of this Koroyd material before?

Thermally formed sure sounds friendlier than vacuum bagging and epoxy methods requied with Z-Plex.

Sandwich structures deliver core benefits
https://www.materialstoday.com/compo...core-benefits/
Quote:
The composites industry has long known that the strength and stiffness of a composite structure can be increased significantly with little additional weight by laminating a core material between two skins. The core of the sandwich serves to distribute shear stresses from loads over a wider area and resist shear and compressive forces better than a single-faced laminate.

Innovative core materials which have proven successful include thermoformable honeycomb, conformable foam and agglomerated cork. These materials can be easily shaped to produce curves and fit into moulds. Recycled polyethylene terephthalate (PET) bottles and carpeting are being used to produce cores that can lower the cost of composite structures. And renewable bio-based polymers are well aligned with new green classifications.
If the Koroyd could be thermally bonded to a skin of similar material to it's core that has been laminated to a fiberglass/Aramid/Kevlar/Carbon-Fiber layer, would it be any better (stronger/lighter) than what's out there?

I would think it depends if energy absorption (impact strength) is favored over stiffness and or other strength measurements.

https://koroyd.com/



Quote:
What’s Koroyd?

Koroyd is a series of engineered tubes that provide impact absorption. The tubes can be cut, shaped, cnc’d, thermoformed or laminated to be implemented into all sorts of helmets and protection. Endura’s new MT500 helmets join Smith’s helmets with the use of Koroyd.


EDIT: Found more information that might answer my questions.

KOROYD IS AN IDEAL STRUCTURE FOR LIGHTWEIGHT CORE APPLICATIONS INCLUDING STIFF SANDWICH PANELS AND BREATHABLE REINFORCEMENT PANELS
https://koroyd.com/structural/
Quote:
HELMET SANDWICH

When applied in laminated shell structures, Koroyd increases the rigidity of the shell helping to spread the load of an impact over the internal liner.

As the load is spread, the shell also crushes acting as a first line of defence, reducing the amount of energy transmitted to the inner liner and contributing to an overall reduction in trauma.




NOTE:
I am looking at this material as a possible car shell or hovercraft hull material.

I think that I read someone was using it as a core material for a propeller, not sure where I skimmed that passage though.

EDIT-2:

Lots more info here:
https://koroyd.com/technology/
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Last edited by kach22i; 09-06-2018 at 12:29 PM..
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