Less of a Drag : Technology: Two inventors say their wind deflector, mounted on rear of an aging bakery truck, cuts resistance and increases fuel efficiency.
There’s never a shortage of bizarre sights in the desert north of Los Angeles.
But the odd-looking contraption that rolls past the Joshua trees and jack rabbits every weekend--its rear end floating and its yellow yarn flapping--takes the cake.
The Tastykake truck is on the move again.
Myles Baker and Dave Levitt have come to race their aging bakery truck up and down deserted roads in an unusual fight against wind resistance.
Their 20-year-old truck, recycled from a Philadelphia cake and pie bakery, has tiny elves painted on its sides. But what catches the eye is the blue plywood rectangle suspended from the rear--the thing that is decorated with dozens of strips of yarn.
The panel is a wind deflector, attached by three-foot brackets to the back of the truck. The men say the vertical panel redirects the airflow that normally causes a suction effect and slows down tractor-trailers.
As goofy as it looks, the gadget is something the pair figure could end up helping save long-haul truckers millions of dollars a year in diesel fuel costs. But first, it has to pass the Tastykake test.
In the driver’s seat, Baker, of Long Beach, is pushing the gas pedal to the floor. His eyes dart between the windshield and a pair of air-pressure gauges next to the steering wheel as he coaxes it to 55 m.p.h. down an empty desert road west of Adelanto.
Standing behind him is Levitt, of Pasadena. He is braced against an empty bread rack as he aims a camcorder at the truck’s speedometer and at the air-pressure gauges. Levitt shouts out the speed as the truck reaches 50 m.p.h., then 53, and finally 55.
The truck is shifted into neutral with a loud thump. It keeps rolling for nearly a minute before it coasts to a stop. Levitt keeps the camera rolling the whole time.
The camera’s built-in clock lets the two 25-year-olds compare how long the truck coasts with the rear deflector panel positioned at various distances from the rear of the truck. A quarter-inch closer or farther from the truck’s rear doors can add or subtract an extra second or so of coasting time.
Desert road tests that started last November support the findings of wind-tunnel tests with a scale-model truck, said Levitt.
The tunnel tests showed a reduction in drag that could cut fuel usage by about 10%--about $2,000 a year for the average trucker, said Baker.
Until now, the only useful wind deflectors for big rigs have been spoilers and fairings that attach to the front of trucks. The Baker-Levitt device has not undergone any independent testing, but last week, they received a patent for their rear deflector.
“While the vehicle is moving, a vortex becomes locked between the plate and the truck’s rear end, creating a low-pressure region. The suction created changes air flow patterns behind the vehicle such that base drag is reduced,” states the patent abstract.
“It’s a fascinating concept. They may have built a better mousetrap,” John Doyle, spokesman for the American Trucking Assns., said Monday. “Fuel costs can be a third of operating expenses in some owner-operator companies. If it’s truly 10%, you’d be looking at tremendous savings.”
The country’s 2 million tractor-trailers travel about 100,000 miles annually and get about six miles to the gallon of diesel.
“All drivers are looking for ways to improve fuel efficiency. That means money to them,” Doyle said after asking for Baker’s and Levitt’s phone numbers. “It sounds interesting. The concept of being able to cut into the drag makes sense.” Baker and Levitt say the deflector idea came three years ago when they were students at UCLA. They were car-pooling to an engineering class one day when they happened to pull behind a big rig and found themselves discussing the aerodynamics of the boxy trailer in front of them.
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The weekend tests became necessary after they graduated. Baker got a job working on supersonic airliner designs at McDonnell-Douglas. Levitt went to work for JPL doing design work for an upcoming Saturn space mission. They borrowed the bakery truck from Baker’s father, Bud Baker of Apple Valley, who bought it years ago to use for apartment house maintenance work.
The desert tests--some of which have been conducted in 105-degree weather--have been an adventure.
The occasional passersby stare at the Tastykake truck. Those who stop and aren’t looking for directions to the nearest town sometimes ask if they have any cakes or pies for sale.
Baker ended up marrying Maureen Sammon, the woman who drives the chase car during the deflector panel tests and watches to see which way turbulence is blowing yarn pieces thumb-tacked to the panel.
About 10 more weekends of work are needed in the desert, according to the pair. They are especially anxious to test in Santa Ana wind conditions, when they’ll turn the truck into the wind “and set off some smoke bombs” for a makeshift wind tunnel test, said Levitt..
Later, Baker said, they will borrow a big rig for some true highway tests. “We need to know how it will affect the guy driving the Yugo next to it,” and how it performs in the rain, he said.
Finally there’s the problem of what to call the device. The name “Locked Vortex Afterbody Plate” that the pair has been using doesn’t exactly roll off a trucker’s tongue.
So in honor of the bread truck they might call it the “Tasty Plate.”
Keep On Trucking Two young engineers have a new patent for a device aimed at cutting wind resistance on trucks. They say that a simple panel clamped on the back of a truck cuts wind drag for a 10% fuel savings. Wind turbulance from big rigs creates a suction, illustrated by sketch, that holds truck back. the inventors say their deflecting plate, shown below, reduces the wake to produce better fuel economy.
