Aerodynamic Toyota pickup
Phil Knox's streamlined 1994 Toyota Tacoma pickup saw its fuel economy go from 25 mpg to 32 mpg at 70 mph just by improving its aerodynamics, reducing its Cd from 0.44 to 0.25, the same as the Honda Insight gasoline-electric hybrid.

Free Fuel Riding on the Wind

Your local home improvement store has what you need to significantly improve your fuel economy

By Jessica Savage

While most Americans are paying more than ever to fuel up their cars, one Texas man has found a way to make gasoline out of thin air - by simply modifying the shape of his half-ton pickup truck.

Using the principles of aerodynamics, Phil Knox's recent additions of an aero-shell, under-belly pan, rear wheel skirts, wheel covers and grill block to his 1994 T-100 Toyota pickup improved his gas mileage by 28 percent over the original highway mileage.

Building, testing and educating the public about aerodynamics, is part of the mission of Knox's Independence Technological Works - IT works. "I'm trying to verify claims of aerodynamics going back 70 years," the Denton, Texas man said.

The passion for aerodynamics awakened in Knox back in 1973 during the Arab Oil Embargo, and after his Air Force tour-of-duty in Vietnam. In early 1974 after reading about the benefits of aerodynamics in Car & Driver Magazine Knox says he was smitten. "Technically, I never recovered from the first oil crisis," he said.

Using the GI Bill, Knox was educated in mechanical engineering technology at Texas Tech in Lubbock, Texas and soon streamlined his first vehicle - a Volkswagen Bus - with sound fluid dynamic principles. The bus achieved a 28 percent improvement in highway fuel economy just by changing its shape. "I've streamlined every vehicle I've ever owned," he said.

Typically, Knox can be found at gatherings such as an Earth Day celebration, handing out flyers and preaching the environmental gospel of aerodynamics, or out road testing his latest innovation. "When you go to a car lot - this isn't fertile ground for a conversation in aerodynamics with the sales people - they don't know the language," he says. The general terms of aerodynamics - drag co-efficient, airflow patterns, frontal area, aspect ratios, fluid dynamics - are not part of everyday conversation.

"I found out by accident," Knox says, "You live it everyday but you don't have the vocabulary to ever talk about it."

From a strictly Capitalist point-of-view, vehicles that are not aerodynamically efficient are losing money and not showing a good return-on-investment. "The business of America is to make money," Knox said, referring to the Horatio Alger quote. So Knox is compelled to urge people to stop buying gas-guzzling trucks and SUVs. "Stop the rags to riches trend these vehicles are setting for America," he advises. "Buy two fuel-efficient cars instead."

The worst offender is the Hummer, Knox said, which when compared to a hybrid car, is like losing 600 percent of a transportation investment. "It's like buying six dinners, eating one and leaving the other five," he said. "It's like stealing fuel from five families." What's worse, Knox says, is Hummers and large pickup trucks are eligible for up to $25,000 in tax break exemptions by being considered farm equipment, while the Environmental Protection Agency says these are the last kind of vehicles America needs on it‘s roads.

But it's not the huge size of these vehicles that's responsible for their terrible gas mileage - it's their bulky shapes.

"It all goes back to Eiffel in 1895," Knox said, "Basically he nailed it." Knox is speaking of Alexandre Gustave Eiffel, the famous French engineer who designed the Paris landmark - the Eiffel Tower. After a career designing bridges and other iron structures all over Europe, Eiffel settled down to conduct experiments in aerodynamics and meteorology, some done right on the tower. These pursuits are actually an extension of architecture because aerodynamics is a huge component of the design of large structures that will be subject to lots of wind once erected.

What Eiffel discovered, Knox said, is that a shape that looks oddly like an ice cream cone, was able to fall off the tower faster than any other object sent down the test cable. "Below 250 miles-per-hour, it's the best shape for a vehicle - an ice cream cone chopped in half with four wheels on it," he said, "It's hard to improve upon."

The world's fastest cars that set speed records are this shape. GM, Ford, Mercedes, Volkswagen, Volvo, Oldsmobile, GMC Trucks and others all use this technology to set records, Knox said. Even NASCAR teams admit that their cars would go faster "backward," as they would take on more of the "teardrop, double-end, pumpkin seed or ice cream cone shape, he said.

While most people don't want to drive around in a car that looks like a race car, they won't need to. An egg, as opposed to a sugar-cube shape with a tapered back is what delivers the benefits of aerodynamics. A counter-intuitive example of this principle is a truck pulling an aerodynamic trailer. Without the trailer, the air behind the cab and tailgate is in the form of turbulence or eddys, creating drag on the vehicle. An aerodynamic trailer streamlines the vehicle and the air flowing over it is smooth and without resistance. "Mass is important but once up to highway speed, a truck with an aerodynamic load can get potentially higher gas mileage," Knox said. Consider that there are 40-ton aerodynamic 18-wheelers that get better gas mileage than Hummers. Knox once pulled a 1,300-pound "aero-trailer" behind his Honda CRX and still got 50 m.p.g.

What questions should vehicle shoppers ask when considering the aerodynamic qualities of their next car?

Here's Knox's suggestions:

What is the vehicle's coefficient of aerodynamic drag (Cd)? These numbers rate the shape of the vehicle, regardless of size. For example, a parachute has the most drag of all and has a Cd of 1.35, while Honda's Dream Solar Champion has a Cd of 0.11. Frontal area: measured in square feet, the frontal area of a vehicle measures the area of air displaced as it advances through the air.

Together, the frontal area and Cd form a vehicle's "signature" or drag index. "Air has mass and you can't go through it without paying for it," Knox said. Large streamlined cars and pickups can go as easily through the air as small, ill-designed "econo-boxes," he said.

By asking questions about the aerodynamics of a vehicle, it will force auto dealers to learn about the qualities of aerodynamics. Buying a car that's not aerodynamic is like buying a house without insulation, Knox said.

Belly Pan
The belly pan was formed from recycled aluminum and sheet metal, as well as discarded bathtub walls from mobile homes.

Anyone could make their vehicle more aerodynamic using the methods Knox used to reshape his T-100 pickup truck. To form the aero-shell that reshapes the cab of the truck, Knox cut rigid foam insulation board into the shape he wanted with a razor blade and covered it with fiber glass, affixing it with a resin glue composite. The belly pan was formed from recycled aluminum and sheet metal, as well as discarded bathtub walls from mobile homes. The grill was blocked off on the outside. Most materials are available at home improvement stores.

To test the fuel efficiency of the truck, Knox drove roundtrip from Denton to Odessa at 70 m.p.h. and achieved a 32 m.p.g. fuel efficiency. A test conducted six months prior to that with only the aero-shell - same route and same speed - achieved 27.5 m.p.g. The truck is rated 25 m.p.g. standard. Toyota publishes a drag co-efficient of 0.44 but with the modifications the truck had a drag co-efficient of 0.25, which is equal to Honda‘s Insight hybrid car, Knox said. No other modifications were made.

"We haven't touched anything under the hood," Knox said, "It's purely through streamlining and drag reduction. Everything is stock, even the tires." Aerodynamics or vehicle shape is the technology that will reduce foreign dependency of oil and empower Americans in fuel efficiency, Knox said.

Whether the fuel source is gasoline or diesel, or an environmentally-friendly source like a hybrid electric or hydrogen fuel cell, applied aerodynamic principles will deliver more miles per gallon.

"It's free horse power, free speed, free reduction in emissions, free fuel," Knox said. "It's like creating synthetic fuel out of thin air."

Times Article Viewed: 118801
Published: 29-Jun-2005


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