Formula Student cars operate in domains of low dynamic pressure whilst competing on circuits with many tight corners and few long straights. Therefore, significant lift (or downforce) generation can be challenging to achieve in racecar terms. The aerodynamics team at UGRacing developed an aerodynamic package to achieve downforce targets whilst simultaneously maintaining efficiency by minimising the drag created by other aerodynamic surfaces. The aero team also collaborate with the powertrain team in performance-critical applications such as the development of air-cooling systems.
Aside from the aerodynamic requirements, the aero team’s goal is to create lightweight and stiff parts that meet regulations and do not compromise the car’s performance, looking at material justification and integrating structural aerodynamic components. As UGR20 was UGRacing’s first attempt to incorporate winged aerodynamic devices, the team set out to gain valuable manufacturing experience working with composite materials and pattern making.
UGR20 adopts a simplistic and conservative design, composed of a front wing, rear wing and undertray. The front wing design produces high downforce with a simple two-element design while providing sufficient airflow to both the underfloor and the two side-mounted radiators. Rear wings on Formula Student cars often carry the highest drag penalty; this is usually attributed to their large size and aggressive multi-element design; the profile drag, and induced drag are more significant. The team chose a conservative two-element design to minimise drag while delivering an excellent aerodynamic pressure balance.
The front and rear wings work together to provide the desired aerodynamic balance. UGR20 positions the centre of pressure slight rearwards of the centre of gravity; this gives the car slightly understeering and predictable handling behaviour, which is preferable for amateur racing drivers.
Computational Fluid Dynamics (CFD) is the primary design tool for developing aerodynamic components. The team ran high-resolution simulations in Siemen’s STAR-CCM+ to study flow structures and cross-component interactions, developing tools and methods to advance and streamline the simulation process.
As part of their efforts to advance the simulation analyses, the team run multi-degrees of freedom studies, investigating the dynamic effects of the vehicle at varying attitudes. These effects are essential to understand as straight-line scenarios are not entirely representative of the overall aerodynamic behaviour. In practice, the team wanted the car to be yawing and pitching away from its static ride height across a specific Formula Student event. Recording the aerodynamic coefficients at varying vehicle attitudes, the team was able to map the aerodynamic performance of UGR20 across a range of ride heights. Figure 2 shows the aerodynamic sensitivity of UGR20’s front wing to vehicle pitch; it is clear that the front wing is most effective when the vehicle is in its maximum dive position.
Compared to the foam-core prototype wings made in October 2019, the team managed to remove 600g from the front wing and 700g from the rear wing thanks to switching to 3D printed inserts and a carbon fibre rod skeleton.
Figure 5 shows the finished aerodynamic package on the car. Looking to 2022, the team aims to incorporate a diffuser with more features than a flat floor and will look to keep the front wing as one continuous piece. The methods of manufacture will continue to be refined, with several alternative materials trialled, and the cost/benefits of adding wings will be examined, which should give greater justification for the overall concept, material and process choices.
None of the work carried out by the Aerodynamics team would have been possible without the support of the partners. The team want to thank the GU68 Engineers Trust and the Scottish Association for Metals for the funding they generously provided, allowing them to purchase quantities of pre-preg carbon fibre, in addition to Tygavac, who supplied the team with all the composite consumables needed for manufacture. The team will showcase its 2022 aerodynamic package in Spring 2022.
