“Formula BMW comprises mini Formula One cars - complete with wings and slick racing tyres - that are capable of speeds of up to 140mph,” explains Trevor Powell, principal of Team Loctite. “Powering the cars is a 140bhp engine that has its origins in the BMW K1200 RS motorcycle. The cars incorporate a state-of-the-art carbon-fibre chassis and fulfil the safety requirements for the far more powerful Formula 3 model.”
During the 2006 season, Team Loctite, with its driver, Oliver Turvey, attained second place in the Formula BMW Championship. He also won the McLaren Autosport Award. This achievement was all the more remarkable as the driver/team combination missed six races at the beginning of the season.
The regulations for Formula BMW mean that standard parts cannot be modified, so they can only be repaired or replaced. Replacement is expensive - and so for repairs, adhesives have proved invaluable. Indeed, a selection of adhesive technologies for a whole variety of applications is to be found in the workshops and pits.
“Every race requires a different pre-load on the cars’ differentials,” Mr Powell explains. “So when it comes to reassembling gearboxes, a silicone sealant is used to ensure no oil escapes from the aluminium casing, and no contaminants get inside.”
This black, flexible adhesive is a single component, non-flowing, room temperature vulcanising elastomer that is effective at temperatures up to 250ºC. Once the sealant has been applied, the assembly is held together with bolts treated with Loctite 243 threadlocking adhesive. “This is a particularly demanding application,” declares Mr Powell. “The gearbox is right next to the exhaust and so very high temperatures are not uncommon. It is a very harsh environment for an adhesive.”
The same product is used to secure the brake calliper bolts. In fact, most of the nuts, bolts and screws on the Formula BMW car are secured with anaerobic adhesives. Those parts that are unlikely to be removed on race day receive the high strength product treatment, while those joints that may require attention are locked with low or medium strength adhesives.
Wherever it is practical, the engineers prefer to use the new stick anaerobics. These are based on the popular domestic glue stick principle and can be carried in a pocket for instant use. The semi-solid formula means there is no mess - and because only the right amount is applied, there are cost savings to be made. As well as threadlockers, the stick range currently includes a retainer, sealant, anti-seize products and a gasket positioner.
“We use an anaerobic for retaining spherical bearings on the suspension uprights,” says Mr Powell. "There is a great deal of vibration during the races and we have to ensure the bearings will not shake loose."
Although most of the parts used on the cars are specified by the race organisers, there is some leeway on certain items for home made components. One of these areas involves the wing mounting brackets. “We have these shaped with a plasma cutter from LS4 aluminium,” says Mr Powell. “They have to be strong enough for us to lift the car, but not so tough that the gearbox is damaged. We take three sets to each race in case replacements are needed following an accident.
“The laminated wings cost between four and five thousand pounds each and are very vulnerable to damage. When we have a mishap we use Terokal 9225 Plastic Repair Kit for repairs.” In addition, Plastic Padding Super Steel and Super Epoxy are employed for metal repairs on suspension struts and castings. Emergency repairs are carried out with Loctite Metal Set - a mineral filled adhesive that forms a self-lubricating surface.
“On race days there is no time for welding to take place, so this two part epoxy - that cures in about twenty minutes - is used to fill up broken castings where the thread has been stripped out,” Mr Powell explains. “A new thread can then be tapped with all the strength of the original. This has to be a complete thread or the race scrutineers will disqualify us for not complying with safety regulations.” Instant adhesives such as Loctite 406 and 431 are used for a number of applications, including the bonding of steering wheel components.
With so many parts on the cars specified by the race organisers, there is little to choose when it comes to mechanical performance. That means the success – or otherwise – of each team is very much down to human effort. This includes both the skills of the drivers and the endeavours of the engineers.
But, as Trevor Powell is anxious to point out, the adhesives play a major role in that human enterprise, too. “The advantage we have with adhesives is efficiency. We are a small team, which means that everyone has a lot to do. And any time we can save without compromising safety has to be to our advantage. By using products that we know are totally reliable we don’t have to spend undue time in checking the joints. That means we can put effort into other activities - and thereby achieve success.”