Founded in 2004, the ITU ZES Solar Car Team has produced a total of 12 vehicles over the past 20 years, including 10 solar cars and 2 autonomous cars. The purpose of producing these vehicles can be summarized under two main objectives: continually setting higher goals and competing on more prestigious platforms.
With evolving circumstances, the regulations of competitions also undergo various updates. As the ITU ZES Solar Car Team, we implement the necessary regulation updates in our vehicles to continue participating in these prestigious competitions, where we represent our university and our country.
Most recently, we participated in the 2024 iLumen European Solar Challenge with ARIba ZES XE, an upgraded and improved version of the ARIba ZES X model produced in 2021. For the upcoming 2026 iLumen European Solar Challenge and 2027 Bridgestone World Solar Challenge, we have decided to develop a new ARIba model.
One of the first and most crucial stages of building a new vehicle is designing and producing its shell. In this process, maximizing aerodynamic performance is critically important for both the vehicle's efficiency and durability. A well-designed shell enables the production of a vehicle suited to racing conditions while simultaneously reducing energy consumption and enhancing overall performance.
Correctly determining the steps of the shell design process plays a significant role in Computational Fluid Dynamics (CFD) analyses, ensuring more accurate design results. This process not only prevents potential issues during the design phase but also allows for the development of a vehicle that meets the desired specifications. Additionally, it saves time and reduces CPU usage.
Shell Design Process
The shell design process begins with reviewing the competition regulations. Competitions like the European Solar Challenge (ESC) and the World Solar Challenge (WSC), where solar cars compete, impose various design constraints to ensure pilot safety and increase competitiveness. These constraints are published prior to the races, and vehicle designs must comply with these rules. Additionally, to achieve low energy consumption and high efficiency, certain aerodynamic expectations must also be met:
Drag Force: The vehicle should experience minimal drag.
Drag Force
Lift Force: Lift force is undesirable. According to the formula below, lift force increases with speed, which may cause the vehicle to lift off the ground, posing a significant danger to both the driver and the vehicle.
Lift Force
Downforce: Since high-speed cornering is not required, downforce should not be generated. Excessive downforce increases energy consumption by enhancing ground grip.
Lastly, the shell design must encapsulate and protect the vehicle's mechanical and embedded systems while keeping them concealed from external view.
HOW IS THE SHELL DESIGNED?
The shell design process begins with selecting a suitable airfoil profile to cover the vehicle's mechanical and embedded systems.
Airfoil
During this stage, the lift and drag forces produced by different airfoil profiles are analyzed, and the optimal profile is chosen.
Next, a surface model is created using Computer-Aided Design (CAD) software, based on boundary lines.
Frame Model
The most critical aspect of surface modeling is ensuring that the surfaces are smooth and tangent to one another. Sharp edges create stagnation points on the vehicle, increasing drag.
Reflection Analysis
In the final stage, the completed model undergoes CFD analysis to evaluate its performance. These steps result in a solar car shell that meets both aerodynamic and mechanical requirements.
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