Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

Bob Sliwa’s 3rd Aero Project Has Shell’s Backing

The StarShip tractor-trailer will get mpg that's "better than anyone else," but the former owner-operator, whose work with aerodynamics goes back to the 80s, is not announcing a target number.

Tom Berg
Tom BergFormer Senior Contributing Editor
Read Tom's Posts
May 13, 2015
Bob Sliwa’s 3rd Aero Project Has Shell’s Backing

 

5 min to read


Fiberglass is laid over a wood frame for the nose of the Bullet Truck, which got 13.4 mpg in a coast-to-coast test.

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.

Ad Loading...

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.

Ad Loading...
HDT editors put Sliwa's first creation on the cover of their November 1984 edition.

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.

Ad Loading...

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 have a carbon fiber body on an International ProStar chassis. Treatments to trailer's rear are as important as the tractor's nose, Sliwa says.

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.

Ad Loading...

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.”

Subscribe to Our Newsletter

More Fuel Smarts

Illustration of exhaust aftertreatment system on an AI-inspired blue background and a green fuel pump nozzle in the foreground.
Maintenanceby Deborah LockridgeJune 15, 2026

New Agentic Predictive Maintenance Report Demonstrates How Degraded Aftertreatment Systems Waste Fuel

Questar analyzed a large mixed-class fleet and discovered it was wasting as much as $30 in fuel per vehicle, per day, because of mechanically degraded aftertreatment systems.

Read More →
Amazon electric cargo bike on New York City street
Fleet ManagementJune 15, 2026

New York City's Microhub Project is Delivering Results

Trucking, last-mile delivery companies, and environmental advocates like what they are seeing so far with New York's microhub program.

Read More →
Red Kenworth truck pulling Paper Transport trailer
Fuel Smartsby Deborah LockridgeJune 2, 2026

Lessons Learned About Alternative Fuels: Start Small, Stay Flexible

Practical advice on adopting alternative fuels and ZEVs from HDT's 2026 Top Green Fleets, from renewable diesel and natural gas to electric trucks.

Read More →
Ad Loading...
Composite image of different angles of the Kempower charger
Fuel Smartsby News/Media ReleaseMay 29, 2026

Kempower Adds Flex EV Charger to Help Support Transition to Megawatt Charging

The Kempower Mega Satellite Flex has both a CCS and MCS connector, allowing operators to serve both types of heavy-duty vehicles.

Read More →
White Hino Le electric tractor on show floor
Equipmentby News/Media ReleaseMay 26, 2026

Hino Adds Electric Class 6/7 Truck

Hino says the Le Series is an important step in the company's efforts to reduce environmental impact and support its customers’ sustainability goals.

Read More →
Sigma Powertrain BEV transmission.
Fuel Smartsby Jack RobertsMay 26, 2026

Can Multi-Speed EV Transmissions Solve Heavy Trucking’s Biggest Electric-Vehicle Problems?

A startup called Sigma Powertrain believes purpose-built multi-speed gearboxes can boost efficiency, reduce battery size and improve gradeability for heavy-duty battery-electric trucks.

Read More →
Ad Loading...
Red Hendrickson e-axle at ACT Expo booth
Equipmentby News/Media ReleaseMay 22, 2026

Hendrickson Debuts Electraax E-Axle for Medium-Duty Trucks

Developed with Driventic, Hendrickson's new integrated e-axle is designed to improve efficiency, reduce weight, and extend range in Class 6-7 EV applications.

Read More →
Fueling trucks.
Fuel SmartsCover Storyby Deborah LockridgeMay 18, 2026

50 Ways Fleets Can Cut Fuel Costs Now — Without Buying New Trucks

Fuel savings don’t come from one big change. They come from dozens of small ones. Here’s how leading fleets are stacking gains across drivers, routing, maintenance, and more.

Read More →
Collage of HDT Top Green Fleets with logo
Fuel Smartsby Deborah LockridgeMay 18, 2026

Top Green Fleets 2026: How Fleets Are Reducing Emissions in the Real World

What works in sustainable trucking today? Heavy Duty Trucking's Top Green Fleets are finding practical ways to cut fuel use, reduce emissions, and keep freight moving.

Read More →
Ad Loading...
Tesla Semi electric truck on display at ACT Expo
Fuel Smartsby News/Media ReleaseMay 13, 2026

California Launching $1 Billion Electric Truck Rebate Program

CARB says the California Clean Fuel Reward program will begin offering point-of-sale rebates of up to $120,000 for electric commercial trucks starting June 26.

Read More →