The neat, tidy design of the Stuttgart entry used a tubular rear frame and a composite monocoque front, with the emphasis on ease of maintenance
more effective it is. Per weight, whatever downforce we get helps us more than a heavier car.’ The average weight for Class
The winning car from Rennteam Uni Stuttgart, en route to taking overall first position in the UK Class 1 competition – one of the few cars to get a dry run in the all-important Endurance event
the garages talking as not only was it the only car at the event with large wings, in common with just a handful of other cars it was also fitted with a downforce- generating under body. ‘Aero in the US is much more common. Events in Los Angeles have six or seven cars with aero,’ explained an Oregon State team member. ‘Most of the time in the Sprint event the top three cars have wings, and we were tired of being the fourth team. Using CFD and lap time simulation, we realised that aero was the most significant thing we could do to improve lap times.’ Weight is a major factor when designing a successful Formula Student car, as John Hilton, chair of Formula Student, says: ‘I believe that light cars go well at this competition.’ Weight is even more critical, however, when optimising performance with aero. ‘The lighter the car, the
1 entrants this year was 218kg, but with the GFR car weighing in at just 156kg and its extravagant aero a mere 22kg, a few more eyebrows were raised. Carbon fibre had a big part to play and was used in the manufacture of the monocoque, wings and panels. In fact, the only steel part was a tube within the nose of the car that was required by the rules.
DOUBLE THE CHALLENGE This may all sound expensive, but the fact that GFR was a collaboration between two teams meant it had double the funding and double the number of students (100 in total), which perhaps explains why it went for double the challenge of using aero. But aside from sheer numbers, building a successful car between teams that are some 8742km apart brought its own challenges, and the results proved an inspiring achievement. ‘It was a huge challenge,’ enthused one team member, ‘How do we make sure a part made in the US is going to be able to bolt up to a part made in Germany? It was something our advisor pushed for to educate us so we had that experience when we go out in the real world. And the response from industry has been great.’ Overall, their combined hard work paid off, but issues with
the car saw it fail to finish the Endurance event. Nevertheless, theirs was the highest-placed team with a non-finish at Endurance next to their name, 15th position overall. Another team to use aero was
last year’s winners, Munich, albeit in a more subtle way than GFR. This was a result of rule changes that allowed more flexibility in aerodynamics, so creating 2D profiles and testing them with CFD, the team began to develop wings and an under body in carbon fibre. Of course, this saw the car gain some weight but, according to the student who led the aerodynamic project, ‘all of the weight that was put onto the car with the under body and the wing was saved with the other parts of the chassis.’ In fact, the design was so intriguing that the team’s main sponsor, Audi, offered the use of its wind tunnel to validate its CFD programme. Unfortunately, time restrictions prevented that from happening. Of particular interest, though, were the ducts that aimed at the tyres. ‘It’s because the rotating masses produce a lot of drag, so we tried to bring the air to flow around the tyres, like a front wing.’ Contradictions are a common
occurrence in motorsport, and no more so than in Formula SAE events, so it’s no surprise to hear that some teams disagree with the use of ‘heavy’ aerodynamics. Such is the case with the University of Bologna, Italy, for
TECH SPEC
Class: Formula SAE Weight: 190kg
Chassis: two-piece hybrid with carbon monocoque and tubular spaceframe rear
Engine: 2004 Honda CBR 600-RR, 67mm bore, 42.5mm sroke, four cylinder, 599cc
Electrics: lithium ion battery, Bosch MS14
Fuel system: sequential fuel injection
Performance: maximum power at 11,000rpm / maximum torque at 8000rpm
Transmission: Drexler limited slip differential, TBR adjustable, single 520 chain, final drive: 3.5:1
Suspension: double unequal length A-arm, pull rod / push rod-actuated ZF Sachs dampers, T-ARB / U-ARB
Brakes: radial mounted ISR caliper, floating disc 240mm / 200 mm
Wheels: OZ Superleggera 7 x 13
Tyres: Hoosier 20.5 x 7.0-13 / 20 x 7.5-13
Length: 2678mm Width: 1405mm Height: 1070mm
Track: 1210mm front, 1175mm rear
Fuel: E85 / 99Ron
September 2011 •
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