'Secret' racing wheelchair could boost athletes' performance
Britain’s Paralympic athletes could have access to a secret new racing wheelchair to give them an edge at next year’s world championships.
Engineers from BAE Systems have been helping UK wheelchair manufacturer Draft and Dimitris Katsanis, the designer who worked on Team GB’s medal-winning track bikes, to develop a new wind-tunnel-tested wheelchair with a carbon-fibre chassis.
Carbon fibre is often used in racing wheelchair wheels but it is more unusual for the material to be used in the frame, partly due to the cost it adds to the chairs, which must be commercially available for use in the Paralympics.
However, Draft’s co-founder and director Dan Chambers, who is due to receive an award from the Royal Academy of Engineering this week, said the new carbon-fibre chassis was six times stiffer than a conventional aluminium one and so reduced drag.
‘The tests we did on the aluminium chassis I make showed that while the athletes were pushing, they could actually distort the chassis enough to cause significant drag by misaligning the back wheels when they pushed on them,’ he told The Engineer.
Draft has also improved the stiffness of the carbon-fibre wheels, he added. ‘Most of the carbon-fibre wheels people have used so far are simply adapted bike wheels.
‘And they’re fine if they’re kept loaded vertically but obviously in a racing wheelchair they’re angled at 12° from vertical, and then also they’re being hit from the side by the athletes so the whole thing does really flex a lot.’
The designers worked with computational fluid dynamics company TotalSim to refine the chair, before testing it at BAE’s wind-tunnel facilities in Warton, Lancashire, where they were able to reduce its drag by around 10 per cent.
This testing also allowed BAE’s engineers to help improve the positioning of the athletes in the chair, cutting drag by a further 10 per cent.
‘We looked at the chair from front to back, top to bottom, so we looked at rolling resistance, we looked at aerodynamics,’ said BAE’s project leader, Kelvin Davies, who described the chair as revolutionary and top secret. ‘The chair by itself is fine but it’s only when you put an athlete in it that you can look at the whole system.’
The wheelchair was developed as part of a partnership between BAE and UK Sport, which saw the engineering company donate £1.5m-worth of its services to the development of sporting technology ahead of the Olympics and Paralympics.
The prototype chair was finished earlier this year but still needed testing by athletes so wasn’t ready in time for the London 2012 games.
However, Chambers said it would be available for the 2016 Paralympics in Rio and hopefully for next year’s International Paralympic Committee Athletics World Championships.
He added that although the chairs would be commercially available to comply with Paralympic rules, they would likely be very expensive. ‘They’re hand-made in Derbyshire; they’re not mass-produced,’ he said.
On Thursday, Chambers will receive the Sir Frank Whittle Medal — the engineering prize for outstanding and sustained achievement — from the Royal Academy of Engineering, which is holding two weeks of events focusing on innovation and engineering in disability sport.