TruckWings spread at speed to reduce drag, save fuel

XStreamTrucking has introduced its TruckWings active cab-to-trailer aerodynamicsystem to the North American market. In itsprototype form, called GapGorilla, it won the company first prize inthe 2016 First Look West (FloW) competition run by Caltech'sResnick Sustainability Institute. Now its shape-shifting approach to reducing drag is heading for the highway with the promise of fuel savings of up to five percent.

Withfuel accounting for a significant proportion of truck running coststhese days, the quest for fuel efficiency has been attractingincreasing attention. While engine, transmission and tireefficiencies continue to improve and yield useful gains, severalresearch studies have indicated that reducing aerodynamic drag cancontribute fuel savings of as much as 12 percent. Consequently,cab-forward designs on long-haul trucks have dwindled as flowinglines have been adopted on engine-forward cabs, and side skirts,under-body fairings, wheel covers and trailer tails have becomemainstream equipment. Alongside those, there have been severalproducts designed to reduce the substantial drag introduced by thegap between the cab and the trailer.

Becausethe rig must be able to turn tightly with the cab rotating at anangle to the trailer, there has traditionally been a large gap therethat creates a zone of low-pressure turbulence. Attempts to reducethis problem have included trim tabs installed around the cabperiphery to smooth the air flow across the gap, curved bulkheadsthat extend forward from the trailer, fixed skirts mounted around thecab sides and roof, and telescoping fifth-wheel dollies thatautomatically reduce the gap at highway speeds. XStreamTrucking's approach is to literally close the gap at highwayspeeds and, according to the company, TruckWings can reduce fuel consumption bybetween three and five percent.

"TruckWings is the first devicewhich completely solves the turbulence problem created by the openarea between the tractor and trailer that contributes significantlyto a truck's overall aerodynamic drag," says Daniel Burrows, XStream Trucking's founder and CEO. "Since two thirds of atruck's fuel bill is spent overcoming that drag, there is a hugesavings to be had by reducing it."

The patented TruckWings design incorporates folding panels made ofimpact-resistant, glass-reinforced composites attached to the rearsides and roof of the cab that automatically swing out to close thecab-to-trailer gap at highway speeds, and retract against the rear ofthe cab at lower speeds to leave room for turning maneuvers.

XStreamTrucking has developed the technology during the last few years,initially validating the concept using computational fluid dynamicsand then conducting wind tunnel modeling at the EnvironmentalProtection Agency (EPA) SmartWay-approved Automotive Research Centerin Indianapolis. With the wind tunnel tests suggesting a fuel savingof up to four percent on sleeper cabs, on-track tests were conductedwith independent supervision by Canada's sustainable transportationorganization, the PIT Group, and then real-world fuel saving testswere run on public highways and witnessed by the North AmericanCouncil for Freight Efficiency (NACFE).

"The exciting thingabout TruckWings is that it is the first solution to automaticallyand completely enclose the sides and top of the tractor trailer gap," says Mike Roeth, Executive Director of NACFE. "This gap areapresents as much as a five percent opportunity with little to noother solutions available for truckers today."

As well as the option to purchase the equipment outright,XStream Trucking is offering a shared savings program to customerswho, the company claims, could achieve full payback after 18 monthsof normal use. Several freight carriers, including two of the US'slargest trucking fleets, are currently running private tests usingTruckWings.

See TruckWings in action in the following video.

Source: XStream Trucking