AERODYNAMIC TRUCKS

At 13.4 mpg, the future
is in aerodynamic trucking

Max Heine|October 03, 2012 Overdrive Magazine

Bob Sliwa's latest Airflow truck

Aerodynamics is getting more attention these days now that diesel has risen fairly steadily for about four months to top $4. You can read a lot more about it in the November Overdrive, where columnist Kevin Rutherford will examine the aero trailer benefits for owner-operators. Also in that issue, our fuel-saving tips list will devote a big section to aero features.

Those who attended the Mid-America Trucking Show this year got a glimpse of aero’s possible future if they stopped by the AirFlow Truck Co. exhibit. The company’s website also has plenty of info on what they’ve done and are trying to do.

 

Most impressive is the results from a test run from Connecticut to California in June. AirFlow says its BulletTruck prototype averaged 13.4 miles per gallon. The website documents the effort and has good shots of the truck, which was originally a 2003 Kenworth T2000. It’s powered by a Cummins 15-liter ISX, with 450 hp and 1,450 ft.-lb. of torque, writes AirFlow President Bob Sliwa. Gross vehicle weight for the test run, which included actual deliveries, was 65,000 pounds and below.

“If we get the investors, we intend to build AirFlow Trucks from scratch and sell them in the (hopefully) near future,” Sliwa says. He points to the 2015, which will be similar to the cross-country test model.

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Peter’s Piece

Airflow’s Bob Sliva is a genius with a long background in trucking, car racing and flying.

As a long time professional driver and one-time pilot, I have often wondered why large trucks and buses have not had aerodynamic designs to save fuel, and make them easier to handle in windy conditions.

Airflow owner Bob Sliwa

Long ago I concluded that while the designers care about styling, they know very little about aerodynamics, and care even less.

Any pilot will tell you about the basics of form drag (the drag caused by the shape of an object as it passes through the air) and he will tell you that with a square solid object, about 70% of the drag is created by the back end, and about 15% by the front and the remainder by the sides, provided they are reasonably smooth and free of obstructions.

It follows that streamlining the back of a truck or bus is vitally important if the drag and fuel consumption is going to be reduced.

But there is another vital area too and that is the underneath of the vehicle.

The underside of aircraft are always closed in and streamlined, and that’s not just to make it look good from the ground. The aircraft designer knows that an open side will create considerable unwanted drag so the underside becomes part of the wrap-around skin.

With vehicles there would be other advantages to be had also from a closed underside.

There is another curious fact about air resistance that is not well known among drivers and fleet operators and that is that for every 1% increase in speed there will be a 4% increase in drag and a corresponding 4% increase in anti-drag fuel consumption.

Bob Sliwa and Airflow Trucks appear to be right on the ball with drag reduction.

The Asker Trilogy