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POWER PLAY

As well as offering spectacular entertainment, truck racing may become an important proving ground for new components

IN An oft-quoted justifiction for motor sport is that it "improves the breed."

As Formula 1 cars rocket around race tracks, car and component manufacturers are hopefully learning something from the exercise and can use that knowledge in future production cars, Can the same be said of truck racing? So far, most of the component manufacturers that have got involved with truck racing have done so because it proves, rather than improves, the breed. Most use their off-the-shelf products in order to capitalise on the publicity value of proving them under racing conditions. Commercial spin-offs far outweigh technical benefits — so far.

Experience has shown that among the most critical components on a racing truck are the brakes and tyres. Brake lining manufacturer Mintex Don has supported half a dozen truck racers in the season that has just ended, concentrating in particular on Willie Green and his Sillwlenebacked ERR Explains Mintex senior project engineer Rod McLellan: "We chose Willie Green because of his driving style: he is very hard on his brakes." To assess the scale of the brake problem Mintex took his truck to Donington Park, a circuit that is particularly severe on brakes because of its long straights followed by tight corners. Using the previous season's brake specification, after four laps the ERF effectively had no brakes. A typical race would be 8-10 laps.

Although racing trucks are without their trailers, and so weigh far less than their working brothers, the speed at which they travel is the punishing factor. The kinetic energy of a moving truck, which has to be dissipated by the brakes, can be expressed as 1/2MV2, where M is the weight of the truck and V is its speed. Because it is squared, therefore, an increase in the speed vastly increases the truck's braking requirements. Under current regulations, racing trucks are limited to 161km/hr (100mph).

The brakes are converting this kinetic energy into heat. A fully-laden working truck in arduous terrain like the Peak District could push its brake lining temperature as high as 400° Celsius. Most racing trucks will go to 500'; because of his brake-dependent style of driving Willie Green can get lining temperatures of 700°. At 6000 linings can begin to burn.

This heat causes the drums to expand away from the linings, but unevenly (called "belling") so that the lining touches only in narrow bands across its width. This banding both severely reduces the frictional area and causes rapid localised wear. In extreme cases the heat can lead to shattered drums and tyre blow-outs.

"Heat management," says McLellan "is the answer." This primarily means air cooling and many racing trucks have a simple ducting system that directs air on to the drums.

Mintex has refined this so that cold air scooped up from below the bumper is ducted on to the specific bands of the drum to prevent belling. The outlet nozzles are also mounted on the steering arms so that they follow the angle of the steered wheels; most systems do not do this.

The second part of Mintex's approach is to use its Safebrake asbestos-free linings. These wear better than conventional linings, particularly at high temperatures and so help in truck racing in which the wear is accelerated and localised due to drum distortion.

WATER-COOLED BRAKES

For Willie Green's extreme needs, Mintex has gone one step further — water cooling. The idea is not new but Mintex has developed it further so that specific quantities of water are sprayed at specific parts of the drum at specific times, It is a non-returnable-system so Green's ERF carries two 30 litre water tanks. This has kept the lining temperature within a range of 130-220°.

The success of Mintex's involvement is apparent in the season's final results. The winner of all three racing classes was using the company's linings.

How much of this relates to real-life haulage? The Mintex Safebrake asbestos-free linings were launched commercially at the same time as they made their racing debut, so the sport can claim no part in their development. Water cooling has no role in everyday opera tions, and there is limited potential for air cooling, according to Mintex's McLellan: "You will never have braking problems on ordinary trucks provided they are maintained and driven well. We have treated racing as an extended test facility and to show that we can live with truck racing requirements with our standard asbestos-free linings."

Truck-racing might have played a part in the development of commercial vehicle disc brakes, but the rules prohibited this. Racing trucks must stay within manufacturer's type-approved specification, so very few competitors this season were able to use disc brakes. This situation may change because there is a movement to change the rules to allow components that are merely approved by the manufacturer, rather than type-approved. "It's an important difference," says McLellan. "Racing will keep pace with technological development, not follow the pace."

Pirelli supplies most tyres to the truck racers. Once again, these are not "specials", but off-the-shelf Zero Degree low profile radials; the LS91/97 for the steering axle and the 1'H20 for the drive axle.

"We don't give them away," insists Chris Famworth, Pirelli's truck racing man. "We assist anyone who wants them, but they pay a supported price. It is not costing us a lot of money.

"Truck racing allows us to demonstrate the performance of the tyres and substantiate our claims."

It is also building business for Pirelli, via greater involvement with fleets that either participate in or watch the racing. The company claims that it has increased its share of the truck tyre market by 50% in the last 18 months — "and part of that is down to truck racing."

Truck racing engines are typically producing double the power output of the standard product; figures of 450-525kW (600-700hp) are common. Surely the engine manufacturers are learning from this? Not really, it seems. The tremendous power output is achieved by the relatively simple technique of over-fuelling, bringing with it very heavy fuel consumption and black smoke. Neither of these have any place in everyday road transport, largely nullifying the exercise from a technical point of view.

Perkins Engines backs four drivers with "tuning advice and help" and gives trackside support to any Perkins-engMed entrant. "We view it as a combination of customer care and increasing product awareness," says a Perkins spokesman.

When the company took over RollsRoyce, Perkins had no name in the large engine market; truck racing has helped to correct that, and the trackside support conveys the message of service back-up, says the company.

When assessing the engineering spinoff from racing, Perkins is less positive: "The technical benefits are difficult to quantify. It's a good test of durability."

LOW PROFILE

Most truck manufacturers have maintained a low profile for their racing involvement, for fear of upsetting customers who do not agree with it. There is also the danger of being associated with a bad accident during racing. They have left racing to their customers or dealers, but quietly help out with spares and technical advice.

Leyland has been a typical case, with its occasional direct participation via its T45 Team with celebrities at the wheel. "It has proved valuable for driver image," explains a Leyland spokesman — the main role of T45 Team is to enhance the T45 range in the eyes of drivers.

It is Leyland who can point to one real, albeit small, engineering modification made to production vehicles as a direct result of racing. At Silverstone last year, ex-Formula 1 champion Alan Jones pressed the Roadtrain accelerator so hard that part of the linkage bent. Ley Above: Scammell deliberately keeps its own name to the fore and refuses to cover the truck in stickers. "We've nailed our colours to the mast" says team manager Dave rigg.

land has since modified the design of the relevent component.

A notable exception among the manufacturers is Scammell, which has a virtual "works" team. "We've nailed our colours to the mast," says Scammell works manager and racing team manager Dave Grigg. The Scammell name is prominent on the S26 racing truck and there is a noticeable absence of other stickers that would, fears Grigg, dilute the Scammell message.

Grigg says that truck racing promotes the company image and provides a platform to meet and entertain customers in a truck environment. "And it's one of the cheapest toms of advertising." He confirms that Scammell has learnt a lot about racing trucks — particularly in respect of handling — "but it's doubtful how much crosses over into the production side." Next season Scammell is to assess synthetic oil in racing.

Les Allen and his brother George are the proprietors of the chassis straightening and axle alignment business Truck Align. They have just completed their first racing season in a secondhand, rebuilt White Road Commander.

The Aliens have straightened or aligned half a dozen of their fellow competitors' chassis but Les Allen is quick to point out that they are not in it just for the business — "we do it for them for half price, more or less." Apart from the fun, the Aliens have had a good deal of exposure from truck racing. "Business-wise its done us a lot of good although it's difficult to put your finger on it."

"What have we learnt from racing? We've learnt what a lot it's costing us!" They have also learnt to check and retighten after each race all the bolted cross-members on the White's chassis, which has a tendency to dismantle itself under the stresses and strains of racing.

OPENING DOORS

Silkolene-backed ERF driver Willie Green is brutally frank in his assessment of truck racing: "Bloody stupid but great fun!" He says that oil company Silkolene cannot claim to have learnt a great deal because he uses commercially-available Silkolene synthetic oil, and nothing has failed. "Its mainly commercial benefit they get. Racing opens doors for the reps."

Rod Chapman finished the season as runner-up in the 224kW (300hp) class, campaigning his Stormont-backed Cargo. He too sees the major benefits as commercial, promoting his business as a Tunbridge Wells truck dealer. He is more optimistic about potential technical spinoffs for the truck industry: "It's early days yet, but think there is a lot to be learnt from truck racing. It's evolved very quickly — just look at videos of races a couple of years ago."

A slight loosening of the rules governing the sport may allow it to become more of a development tool for manufacturers. At the same time, the organisers (the British Truck Racing Association and the European Truck Racing Organisation) primarily want to keep it reasonably close to working trucks so that the industry can still relate to it. They also have to tread the line betwen making it spectacular and keeping it safe.

There are signs that manufacturers are taking truck racing more seriously and it is predicted that some will be participating in a more open manner next season. This is almost certainly for commercial reasons but it must increase the chances of some genuine engineering spin-offs, no matter how slight.

by David Wilcox