Here’s a new twist on aerodynamics: curved blades inside a rectangular structure that smooth air flow as it leaves a trailer’s surfaces. Called the VorBlade Invisible Fairing, the device is combined in rows at the trailing edges of a box trailer, reducing turbulence and the suction effect at the vehicle’s rear.

The result is 5% or better fuel savings that have been independently tested and verified by EPA’s SmartWay program, according to AvanTechs Inc. in suburban Denver. Representatives showed them last month at the Technology & Maintenance Council’s annual meeting in Nashville, Tenn.

The VorBlade concept was inspired by straight-bladed vortex generators on the wings of jet aircraft that travel at 500 mph or more, they said. Those don’t work at much lower highway speeds, so researchers specializing in fluid mechanics developed the more complex assembly.

Air is grabbed by a VorBlade’s leading edges and funneled through its structure, creating a 10-foot-long vortex that leaves the trailer’s surface with reduced drag, enough to cut fuel use by 5% to 6%, the company says. Added also to the trailing edges of tractor surfaces, fuel savings rise to 8.76%.

VorBlades work in oblique winds of up to 20 degrees, the company says.  Fashioned of aluminum, the devices are attached in rows.  Affixed in multiples to metal strips, they form VorBlade Wings for the rear edges of a trailer’s sides and its roof. These provide 7.3% to 9.5% in fuel savings, the company claims.

A full set of VorBlades weighs about 60 pounds. They protrude about 2 inches to the top and each side – slightly more for the wings -- but federal regulations exempt them from height and width limits.

They are easy to install and can be removed without damage to a trailer’s surface, the company says. More detailed descriptions are at the company’s website, www.vorblade.com, and videos are posted on YouTube.