Affordable supercar unveiled

Two British engineering consultants who helped build the million-dollar McLaren F1 and Mercedes-McLaren SLR supercars say their latest project is the world's first road car to exceed the optimum power-to-weight ratio of 1000bhp-per-tonne.

But they say development of the lightweight prototype they call the Freestream T1 couldn't be further removed from the usual no-expense-spared approach to supercars. They expect the finished price of the Freestream T1 to be around £150,000 ($385,000).

Said Freestream co-founder Ben Scott-Geddes: "The same key issues facing mainstream car designers, such as active and passive safety, vehicle performance as well as weight, complexity and cost, were all addressed at a fundamental level."

"It was a primary inspiration for the car. To demonstrate our understanding of these issues we set out to design an optimum package for delivering 1000bhp-per-tonne."

Their vision was an ultra-lightweight car capable of going from zero to 160km/h in five seconds and on to 330km/h and beyond.

Its design had to develop enough downforce to corner at more than 3g - about the same as a Le Mans prototype - with the ability to stop on the proverbial sixpence.

"Interestingly, the sweet spot on the curve that satisfies many of these issues is 500bhp in a vehicle with a mass of 500kg," said co-director and engineer Graham Halstead.

"You can deliver higher engine outputs up to 1000bhp and beyond, but that means more weight, which adds significant cost and complexity to the car. Conversely, a 300bhp-per-300kg approach can compromise crash worthiness because of insufficient structural mass.

"An extremely lightweight approach can cause costs to spiral through the use of exotic materials. And less horsepower means a restricted top speed and aerodynamic performance.

"Having arrived at the optimum power-to-weight ratio a major engineering challenge was to design a powertrain of around 100kg, without which it would have been impossible to meet our overall vehicle design requirements."

The Freestream T1 is powered by a bespoke 2.4-litre supercharged V8 aluminium engine weighing around 85kg. The six-speed sequential transmission with magnesium casing weighs 30kg.

The carbon/aluminium honeycomb monocoque features a separate composite crash structure at the front, while the rear sub-frame specifies aerospace grade steel. The same steel is used in the suspension.

Scott-Geddes and Halstead haven't disclosed the car's exact weight but they say they built it to show off their skills.

"Concept vehicles are ten-a-penny and this is more than a one-off prototype," said Scott-Geddes. "The only way to truly convince carmakers that we have the experience and skills to design and engineer a safe, reliable, cost-efficient albeit high-performance car is to actually design and build one."

Said Halstead: "In addition, there is a global market for an exclusive ultra-high performance track car that can also be used on the road. So in effect we've found an exciting way of funding our demonstrator."