Record entries for Formula SAE
BY IAN PORTER | 11th Dec 2015
The Monash Motorsport crew has set itself a difficult task by starting with a blank sheet of paper this year, while the team from Edith Cowan University – which ran second in 2014 and 2012 – has opted for an evolutionary approach to what was an adventurous design last year.
The Edith Cowan team fell just short of toppling Monash in 2014, amassing 881 points over the 10 scored exercises to Monash’s 915.5 points, to make it the closest finish ever seen in the event’s 15 year history in Australia.
Apart from 24 universities from around Australia, the field includes teams from Roorkee in India, Canterbury, Waikato, Auckland in New Zealand, Tokyo Denki University, Taylor’s University in Malaysia and the University of Missouri.
Changes to the rules means it will not be business as usual for the teams this year as there has been a major tweak in the regulations relating to aerodynamics.
Last year, teams were allowed to have their rear-wing endplates in line with the outside of the rear tyres. This year the endplates have to be in line with the insides of the rear tyres, theoretically cutting the downforce available.
“We revisited our complete concept at the start of the year. It’s a complete ground-up redesign,” Monash team leader Areeb Hassan told GoAuto.
“We had to look at a whole range of things because of the rule change.”Part of the thorough redesign of the aerodynamics was the decision to bring back bodywork on the Monash car, in the form of sidepods between the front and rear wheels, Ms Hassan said.
The team is expecting some dividends from a new suspension, too. It has gone for a hydraulically interlinked system that allows each wheel to react to the road surface without disturbing the contact patches on the wheels.
“They can move individually, but in roll, pitch and heave they are damped through the system,” Ms Hassan said“We have also changed our engine this year and gone to a KTM single cylinder, a 500 EXC,” she said, which replaces the KTM 450 XSF used previously.
Teams are not allowed to use a production engine that has a turbocharger already built in, so the Monash team then had to engineer its own turbo for the new 500. The rules allow any engine up to 610cc.
The Edith Cowan team has returned with its ground-breaking all-in-one engine block/gearbox/differential unit that is machined from a 150kg billet of aluminium and weighs 18 kgs when finished.
Team leader Nathan van Vugt said the team has completed a refined version of the design but said that will not be used until the team travels to Silverstone for the British Formula SAE contest.
“We still have the version one on the car. It’s too reliable. We haven’t had to replace it yet.”The team has further reduced the car’s centre of gravity from 180 to 175mm, while other cars are still around 250mm.
Part of this lower centre of gravity is the adoption of a planetary gearbox for the steering actuating two Pitman arms.
Mr van Vugt said the radical steering system made it easy to have variable Ackerman during cornering. The Ackerman principle involves turning the inside road wheel more than the outside wheel when turning into a corner.
“So we have parallel steer at high speed and, at slow speed, we have quite a large amount of Ackerman to help the car turn into the corner better.”The team has also placed some wings on the sidepods in a bid to make up for the smaller rear wing and added 3D wings on the front, imitating an aircraft wing with a thick leading edge and thinner trailing edge.
“We are actually making more downforce that last year, because of the sidepod wings and the 3D elements at the front.”The RMIT electric vehicle team – the university has also entered the internal combustion category – has stuck with its single motor concept rather than switch to hub motors.
“We have aimed to keep it simple and reliable,” team leader Josh Gurtler said.
“Hub motors bring a lot of unspring weight and higher complexity in the drive systems,” he said.
The RMIT electric vehicle came seventh overall in 2014 and was the first EV.
Mr Gurtler said the team focused on tightening up the packaging of the batteries, motor and inverter behind the driver. Shorter cables weigh less.
The motor drives through a Drexler limed slip differential and chain drive to the rear wheels.
“It’s a single speed set-up because electric motors have plenty of torque at slow speeds,” he said.
The RMIT electric vehicle departs radically from the internal combustion cars because it does not use any aerodynamic devices.
“We don’t use wings because wings would increase our drag and increase our energy consumption and, therefore, we would need more batteries which would increase our weight overall. It’s a never-ending cycle of weight addition.”“We have proved you don’t need aero to be successful.”Mr Gurtler said the car would have to carry an extra 15 kgs of batteries on top of the 68kgs it now has – if it was to have similar aero to the petrol cars, but fitting them would cause packaging problems.
Either the driver would have to be moved forward in the chassis or the wheelbase increased, both of which would upset the car’s 50:50 weight distribution.
The rules of the Formula SAE contest cover more than just car design.
The students have a strict set of design rules they have to observe and they have to accurately cost their designs and ensure they are (theoretically) relatively cheap to manufacture.
They have to present their designs to a simulated board of directors as if they were pitching their car for a company to put into production.
On Saturday, the last of the teams will conduct their design and cost presentations and then the 30 teams will compete on the skid pad and in acceleration runs. In the afternoon, they will compete in the autocross contest.
Sunday will see plenty of action on the track as the teams each complete two heats in the endurance section, which tests reliability and fuel consumption.
