For the second year running Delft University from Holland won the Formula Student (FS) engineering competition at Silverstone. Its all-wheel-drive electric vehicle is a feat of detailed engineering, packed with innovative concepts.
The most noticeable change is the car's aerodynamic package featuring totally different wings, due to rule changes in Formula Student .
Much of the car’s aerodynamic package was designed in Computer Fluid Dynamics (CFD) using Open FOAM software. Here, Delft has made a big step in the past, as its CFD project was reliant on a privately owned group made up of 36 computers (all of which were old university cast offs). Using this system, solving the case would take twenty-four hours which limited the amount of optimisation that could have been done to the overall aerodynamics of the car.
This year’s aero sees an evolution from 2014, even if Delft didn’t quite finish it, they have still done a lot of work. The front wing includes a foot plate with a set of end plates on either side. Up one level, is a flap which is the same length as the foot plate. Where their wing differs from other universities, is Delft have an inboard flap section which makes up a wing to guide air flow over its exposed front suspension.
One can see the inboard fence with an extra flap, taking part of the front wing assembly to three-tier high. The angle of attack is quite aggressive, therefore the tyre’s wake does not affect the rear as much (as other designs), as no air flow is allowed underneath the tyre.
On the side impact structure, Delft looked into the floor for an aerodynamic gain. They created a big end plate on the side of the car which helped the flow to the diffuser. In front of the rear wheel, Delft added a winglet, similar in design to what Williams Martini Racing ran on the FW37 in the Austria Formula 1 test. The winglet is two tiered, enclosed by an outer end plate and connected to the monocoque.
This helped flick up the air flow to the giant rear wing main planes. By this, Delft used the pressure difference as a downforce benefit, (which may have been overlooked by other universities).
When looking at the rear wing assembly, it is easy to note its sheer volume. In the wing, one can see three aerofoils instead of one, to create an even greater angle of attack. These are mounted via endplates on the both leading edges, which help reduce the vortex acceleration and size.
The whole wing is mounted by four composite tubes which lead straight to the rear wheel wishbones. It’s a free standing design, which is different. All the other teams mount their wings to the chassis rear bulkhead or the sub-frame.
images: DUT Racing
by Stefan Ruitenberg