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11/08/2011
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The automotive sector needs some disruptive technology to shake up the way cars are made, and the creation of new engineering skills may be a positive side effect to the changes, Formula One engineering icon Gordon Murray tells Matthew Valentine.
 In an era of change, one product key to modern life is beginning to look a bit old-fashioned. The fundamental process of mass producing cars has changed little since the introduction of the Ford Model T in 1908, contends Gordon Murray. "Even though those vehicles had a separate platform, it was still a standard steel body, welded together, painted and the bits assembled onto the finished motor car," he says. "And we now use aluminium for primary structures instead of steel, and we use some plastic mouldings for bumpers and wings and things like that. But, essentially, we still make cars the same way."
As well as being old-fashioned, the traditional methods are also capital-intensive, requiring enormous investment, and energy-intensive in terms of materials and processes, says Murray. Before environmental issues attained their current high profile, Murray had already been convinced that smaller, lighter cars would become essential to help maintain personal mobility as traffic levels grew.
Having always worked on low-volume sports and racing cars, he began to examine the hardware and methods involved in the mass production of small cars. "It soon became obvious that the reason why car companies didn't encourage people to buy small cars, and the reason they didn't make smaller, lighter cars, was because you don't make much profit on them. If any profit at all," he says.
Costs, however, are very similar to those for larger cars, which can be sold for more and equipped with more 'content' – expensive extras – to drive up profit margins. Murray started seeking an engineering solution to making smaller cars more cost effective to manufacture in high volumes, and soon turned to an area of which he has vast experience: structural composites.
He designed the first Formula One car to use carbon fibre, in 1979, and the first car to use it on the road, the McLaren F1. There are three traditional reasons that structural composites have not been used in high volume car production: unit price, cycle times and the difficulty of attaching point loads to a composite panel. The solutions to these comprise the starting blocks of iStream, a new vehicle manufacturing system that Gordon Murray Design has developed and is now selling to manufacturers.
"If you say structural composites, people immediately think of carbon fibre. But there are other fibres and there are other matrices you can use to hold the fibres together that don't have to be epoxy, and it doesn't have to be carbon. So we started looking around and we're got a very low cost system for the actual monocoque panels," says Murray. Cycle times for low volume carbon fibre cars are too long for mass production, he says: "Epoxy resins in thermoset composites are hours in an autoclave and you'd need so many toolsets to make even 5,000 cars a year, let alone 100,000 or 500,000, so we set about working with various suppliers to reduce the cycle time. We've got it down to 100 seconds."
Yet the most important problem is that of attaching point loads to a composite panel, which is essentially two skins either side of a flimsy core material. "It's very, very difficult, because you need an insert to spread the load. When you're hand making a Formula One car, or even a sports car, you can have a template and drop in 160 inserts. You've got all week to do it and the time doesn't really matter. But when you've only got 100 seconds, taking point loads out in composites is virtually impossible. So the other bit of iStream is that we use very low grade steel, mild steel, and we make the world's simplest frame. It's not a spaceframe, it's just a frame that essentially joins up all the point loads," he says.
Mountings for everything from seats and seatbelts to the engine and suspension components are located on this simple frame. "That itself doesn't need to be strong or stiff," says Murray. "Once you bond the monocoque into it with a robot you've got a massively safe, strong, lightweight structure. And, in one fell swoop, we're reduced the capital investment, we're reduced the weight, we've increased the safety because of the strength of the shell around you... and we've got flexibility beyond anybody's wildest imagination."
From a commercial point of view, the ability to build to order is a kind of Holy Grail. Current production from car manufacturers is invariably stockpiled. A sudden economic downturn can lead all too quickly to fields full of unsold cars because factories are like a sausage machine that can't be turned off, says Murray.
The iStream system is designed to be more flexible. A central plant would manufacture the basic frames, while smaller, local assembly areas would put the cars together, to order. The plants would be small enough to back on to sales operations, says Murray: "You could walk in, choose your car and come back three days later to watch it be put together."
The system can be applied to any size of vehicle, from city cars to buses. The capital investment to set up an iStream manufacturing system is around 10 per cent of that needed for a conventional car plant, and is uses less energy too. Talks are underway with a number of parties interested in licensing the system.
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Author
Matthew Valentine
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