Automotive Engineer

It’s a bold claim to say that you make the most efficient electric car in the world. But that’s what Gordon Murray Design says of its T.27, stating that it uses 29% and 36% less energy per kilometre than the Smart EV and Mitsubishi iMiEV respectively.

The point that Gordon Murray really wants to make is that, for electromobility to be successful, you need to change the way you design and manufacture the vehicle, not just how you make the wheels turn.

Put simply, the company thinks in terms of low-cost composites, not stamped steel and spot welds. The manufacturing process it has developed, which it calls iStream, has delivered an EV weighing just 680kg – 130kg of which is the 12kWh Li-ion battery – with a range of more than 160km on the NEDC cycle.

“We analysed EVs’ costs and it was always about the battery – it’s half of the cost of the car,” says Gordon Murray Design’s engineering director, Frank Coppuck. “So we’ve concentrated on low weight because that means a much smaller battery pack. But we haven’t compromised on range. We’ve set a target on the combined cycle of 160km – we’ve just got over 176km, and on the urban cycle it’s over 208km.”

Chief executive officer Gordon Murray says that, although prediction of take-up rates for EVs globally between now and 2015 vary by up to 80%, the two biggest obstacles remain range and price.

Consumers probably don’t even know how much electric range they really need. But they’re likely to be sceptical of quoted figures, given the difference they can experience now between official fuel consumption figures and what they see when filling the tank with gasoline or diesel. 

The cost issue is complicated by the different subsidies offered throughout Europe.

“If you aim for a 160km range you’re going to get 95 or 110 in real life,” says Murray. “We wanted a real-world range of around 160km – we think that would be acceptable. And we don’t want government subsidies. The T.27 could sell for under €17,200 and make a handsome profit for whoever manufactures it. Those were our targets.”

The composite monocoque that enabled the engineering team to meet those targets has a nominal wall thickness of 20mm and has the advantage, Murray says, of inherent stiffness, so heavy-gauge steel sections and pressings aren’t needed to carry crash loads or provide torsional rigidity.

And stamped steel, he adds, can only go so far unsupported – no matter how many ribs or flanged holes you punch in it – before you need extra members to provide localised stiffness.