ATLANTA — Street Shark. The name says it all for the award-winning polyurethane car hood from Frimo Group GmbH on display at JEC Americas.
Most car hoods are smooth. The Street Shark has a textured finish, which actually cuts wind resistance, as well as reducing weight. The hood netted an Innovation Award in the automotive category at JEC Americas, the composites trade show in Atlanta held May 13-15 at the Georgia World Congress Center.
If you look closely, it resembles thousands of tiny bird prints. Actually, Frimo marketing manager Sven Garcia Alba said, the surface is that of a shark skin — and Frimo used skin from an actual shark to design the aluminum mold for the part, made by resin transfer molding.
“In Germany, you have to wait until a shark in a zoo dies, because you have no way of importing it, the shark skin,” Alba said.
Frimo ended up using a small section of the skin of the shark, a fish that knifes through the water, thanks to a uniquely textured surface.
“We made a mold of silicone out of this, then transferred it to the final mold. The final step was enlarging the structure,” he said.
Real shark skin feels like fine sandpaper, but the hood texture had to be enlarged to get the same effect in the air, which has lower density than water. Other than the larger size, Alba said, “It's exactly the same structure of the shark that died.”
Alba, who was stationed at the Street Shark display during the show, repeated his explanation countless times: It's a case of industry learning from nature. It's scientific. And it's cool: Prototypes are used on special modified versions of two sports cars, the Porsche 911 and a BMW Z4. The special BWM Z4 has Street Shark on the roof and hood. The Porsche, now being made, will have a hood with the material.
The PU hood weighs about four pounds less than aluminum hoods used on those two cars.
“It's lightweight and it reduces drag,” Alba said.
The reduced drag is like the puck on an air hockey game — air floats over the surface without touching the hood. Even better, the “skin” helps the air actually flow faster over the surface.
“The extruder which the Shark has, builds a very small turbulence on top of the surface, which builds a kind of a layer on this top,” Alba said. “Flowing air is not touching the part itself anymore — like going over wheels.”