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Fleet hauliers are always looking for even the tiniest reduction
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in fuel consumption—it can add up to hundreds of thousands of pounds a year. One answer is to become smooth operators —by adding aerodynamic kits to tractors and trailers. Steve Banner reports.
Fed-up fleet operators contemplating a move to the Netherlands to benefit from all that cheap diesel should have a chat with Val Dare-Bryan first. An expert on truck aerodynamics, he argues that hauliers should think about the fuel consumption benefits that air management kits can bring before they emigrate with their artics.
"It's now possible to achieve 12 to 13mpg with a 38-tonner," he believes. "And you'll improve your journey times because the more aerodynamic a truck is, the faster it accelerates." Better acceleration times are particularly important now that trucks are restricted to a maximum 56mph, he adds.
Dare-Bryan's latest design involves a fixedheight fairing on the tractor unit's roof plus a deep collar extending back from the cab sides. It narrows the gap between tractor and trailer to a tight 400mm, and a door is built into the collar to allow the driver access to the suzie connectors. A saddle-type moulding is mounted across the chassis to reduce air turbulence between the trailer and the unit.
Trailer skirts are also required, and DareBryan has come up with a flexible skirt which offers a gap of just 100nun between the bottom of the skirt and the road. "We can now get a 38-tonner's drag coefficient down to below 0.4," he says, "less than a typical family saloon car."
Dare-Bryan's interest in aerodynamics and what can be achieved stems from 20 years in motor sport. "I worked for all the major motor racing teams at one time or another," he recalls. "I was very much involved in the development of air dams and the use of what is known as ground effect, where you get a high downforce, but low drag."
Worries about the cost of accidental damage to skirts and other fittings on commercial vehicles are groundless, he believes He works closely with kit manufacturer AB Airflow Systems of Shefford in Bedfordshire, which is about to move to nearby Sandy. "The number of replacement parts sent out each month is very small, and if operators aren't ordering parts, they're not sustaining damage," he says. And air management systems make a truck look better—if a driver is proud of his vehicle, he's going to look after it."
What about the cost of fitting the necessary equipment? "We're talking about £1,400 to kit out a tractor and £1,200 for a trailer," he says. In doing so, you'll add 4060kg to the weight of the former, and 80120kg to the latter, he adds.
And tanker trailers? "Contrary to what some people might believe, they're not naturally aerodynamic," says Dare-Bryan. "In effect you've got a box—the tractor unit— followed by a tube and that poses some air management challenges" Dare-Bryan's response has been to concentrate on making the tractor unit more aerodynamic, and leave the trailer alone. "The operators prefer this approach," he says. "Tanker work is usually payload critical, and they don't want too much weight added to the vehicle because it reduces the amount they can carry."
Argos and TNT have both consulted DareBryan at one time or another, and they agree that enhanced aerodynamics spells reduced diesel bills. "It's difficult to quantify, but I believe you can see a fuel consumption improvement of possibly 15%," says Roy McGrudden, fleet engineer at Argos Distributors. "The skirts on trailers are susceptible to damage, however, so we fit a rub rail along each side to protect them.
"The ferry operators moan about difficulty getting access to the lashing rings—we deliver to Argos locations on the Continent— but they usually only use the front and back rings anyway," he says. "Fouling the ramps going on to the ferry isn't a problem because the skirts generally taper upwards so that they're level with the underrun bar at the back" While McCrudden favours trailer side skirts, he draws the line at wheel spats. He fears the wheels, tyres, and brakes will get too hot, and that anything that impedes access to the wheel studs could lead to maintenance being neglected.
In 1990 TNT was involved with DareBryan in trials of aerodynamic trucks which also involved the Department of Energy For 12 months trucks with air management kits were run against standard vehicles out of two depots, and diesel savings of around 16% were achieved, says technical services manager Richard Catley. "Those savings have been borne out in the day-to-day running of TNT trucks since," he says.
Some 500 tandem-axle aerodynamic Cartwright boxvan trailers are now in service with TNT—the air management system they use is the only one to have been approved by the Department of Energy—and the trailer was one of the runners-up in the dry freight section of this year's Commercial Motor Trailer of the Year Awards.
Boots, too, has consulted Dare-Bryan. Distribution support manager Martin Owens points to one sometimes overlooked benefit of trailer skirts. "They create a "vacuum" beneath the trailer which sucks spr opposed to squirting it out,"he says, improve road safety" Aerodynamics only really start and reduce fuel consumption if a v travelling at above 50mph, he belies means it's the company's trunkers the treatment its city-centre delivery don't The need to create as slippery a possible hasn't been lost on D Complete with buckle-less curtains catching air management equipn Palletmaster 2002 carried off CI Freight Trailer of the Year Award produced more than 100 since customers include Whitbread and T Britten," says marketing manager Blurton. "It's not just the potential fu that appeals to them," he adds. "TI looks a million dollars into the barga Aside from reducing air turbuler the sides, the lack of buckles mo curtains are easy to open, easy to ke and the whole curtain is avail signwriting, he says.
The design has safety benefits tor believes. "The wheelarch design spray, and the rear lights are also vie the sides because of the way they art he says. Fears about the skirts damaged have so far proved gro "The trailer looks so good that dr being extra careful."
The Brewery Transport A Committee trials in July showed Pal 2002 could generate a 35% fuel saN Blurton. "That's the equivalent of ov annually if it averages 100,000 mile he says. "That puts the total pre £2,000 that it commands into perspc There's no reason aerodynamic au be retrofitted, and they can generate sort of benefits as those fittec vehicles. Several companies speo them, and a number of used trucl install them to enhance the appeal c four-year-old vehicles.
Dare-Bryan believes further dev of air management systems can c yet more to paring down hauliers' even more thought will have to go design.
'The struggle is getting harder,' "But I want to see 15mpg at 38 ton believe it can be achieved."