The first Arab Oil Embargo of 1979 got fleet managers interested in trying to save increasingly expensive fuel, and by the second embargo in '79, some were using roof-mounted air fairings on their road tractors to reduce drag. That got the attention of owner-operator Bob Sliwa, who saw the sense of aerodynamics but figured a lot more could be done.
He started working to improve his “square” Ford CL9000 cabover, whose Cummins diesel was getting a typical-for-the-time 4.4 mpg. He added smoothly contoured fiberglass panels on its front end, a bulbous shield on its roof, and deep side skirts to his van trailer.
With careful, light-footed driving during one test, Sliwa got 10.4 mpg. HDT editors learned of his results and put his rig on the cover of their November 1984 issue.
Sliwa left trucking to pursue other interests, but later formed AirFlow Truck Co. and returned to the mpg quest in 2008 when he began working on the Bullet Truck, styled after and named for Japan’s Bullet Trains.
Based on a Cummins ISX-powered ’03 Kenworth T2000, it also pulled a deeply skirted van trailer. It got 13.4 mpg in a coast-to-coast run hauling a revenue load and grossing 65,000 pounds. He ran it in daily service and got similar results.
“Going around the country, every load was a Landstar load,” he said in reference to the company he was leased to. “They were loaded and unloaded normally. For that year (2012), people would say, ‘Oh, you’re going to rip the skirts off that truck. No, I didn’t.”
They also scoffed at his Double-Nickel cruising speed, but it was entirely feasible with steady driving. “At 55 (mph), I’d see a truck pass me four times during the day – I’d pick one out because of its appearance—and at the end of a day he’d end up parking next to me at a truckstop.”
He exhibited the Bullet at truck shows to drum up interest and attract sponsors – among them Cummins, Goodyear Tire and Flex-a-Lite fan -- to pay for his development work and the downtime it required.
Sliwa continues his aerodynamics work at a shop at Newington, in central Connecticut. He’s into his third project, which he calls the StarShip. And he has picked up a major sponsor, Shell Lubricants.
“Shell is always looking at ways to improve fuel economy, and at working collaboratively with others for improvement beyond working on our own,” says Dan Arcy, the firm’s OEM technical manager. He declined disclosing the dollar amount involved in the backing, but said it includes consultations with Sliwa by Shell engineers.
StarShip will be based on a 2016 International ProStar chassis that Sliwa bought through “my good friend, Royal Jones,” at Mesilla Valley Transportation, a progressive, fuel-economy-conscious fleet in Las Cruces, N.M., that owns an International dealership. He removed the stock cab and nose and will replace it with a smoothly contoured body. Its main material is lightweight carbon fiber.
The ProStar’s components include a Cummins ISX15 diesel, Eaton UltraShift Plus automated 18-speed transmission, and a Meritor 6x2 tandem with a 2.50 axle ratio. The Cummins will operate in downspeed mode, near its 1,000-rpm torque peak, Sliwa explains, and he’ll probably change the axle’s differential to an even lower 2.10 ratio. The double-overdrive 18-speed will provide flexibility in choosing cruising speeds for testing. He’ll test StarShip at 65 mph because many fleets operate that fast.
StarShip will be an integrated tractor-trailer using a 53-foot dry van. The trailer will have deep side skirts, gap-closing farings at its nose and a boat tail structure at its rear. Testing and experience has shown that “the trailer’s rear is more important than the tractor’s front,” Sliwa says. “The best shape is a teardrop,” but he doesn’t think that’s practical for a 13-foot, 6-inch-high vehicle that hauls regular freight, which his trailer will be expected to do. He’s been talking with trailer builders and expects to choose one soon.
Integrating a tractor and trailer yields the best possible aerodynamics and fuel economy, so is the basis for SuperTruck rigs that three original equipment manufacturers have developed under Department of Energy’s contracts. Sliwa believes vehicle integration is unrealistic for multi-trailer drop-and-hook operations, because trailers sitting in yards or at docks do not make use of their aero improvers. But integration will work for an owner-operator with his own trailer and fleets with one-to-one tractor-to-trailer ratios.
With Shell’s support, StarShip development will include computational fluid dynamics and will stretch well into next year, he says. A mockup should be done by summer of 2016, shakedown testing to prove structural integrity by autumn, and regional and long-distance freight hauling by 2016’s fourth quarter.
Arcy says Shell will probably use SuperTruck’s diesel to demonstrate the PC-11 motor oil that it’s formulating, and possibly other low-viscosity, low-friction lubricants. (Arcy chairs the American Petroleum Institute committee that’s developing the proposed-category oil for the newest engines.)
What’s StarShip’s mpg goal? Sliwa declined to name one, except that it will be better than the Bullet and “better than anybody else.” And he’ll spend “a lot less than (the) $115 million” that a major OEM says it’s invested in a concept tractor. Long-term, he has additional ambitions.
“I aspire to be an OEM,” building entire aero trucks using stripped chassis, similar to his StarShip and Bullet Truck projects, but in greater volume, he says. “If a big fleet gave me a commitment to build 100 trucks, then I’d go to the bank and see what I could do.”