Formula 1 Aero Insights Pt.2: Single vs Multi-Element Rear Wings

Rear wings are crucial aerodynamic components used in high-performance vehicles, especially in motorsport, to generate downforce and improve stability and grip. The design of these wings significantly influences a vehicle’s handling and performance. This article compares the aerodynamics of multi-element rear wings and single-element rear wings, exploring their advantages, disadvantages, applications, and the physics of airflow.

Single-Element Rear Wings

A single-element rear wing consists of one continuous surface (airfoil) that extends across the rear of the vehicle. This type of wing is relatively simple in design and offers distinct aerodynamic characteristics.

One of the primary advantages of single-element wings is their simplicity. The straightforward design makes them easier to manufacture and install. Additionally, single-element wings generally produce less drag compared to multi-element wings due to their smooth surface and simpler flow structure. Another benefit is the ease of adjustment; adjusting the angle of attack (tilt) of a single-element wing is relatively simple, allowing for quick tuning to optimize performance for different track conditions.

However, single-element wings have their limitations. They are less efficient than multi-element wings in maximizing downforce without a significant increase in drag. This means they generate less downforce overall. Furthermore, the aerodynamic characteristics of single-element wings are less adaptable to varying speed ranges and track conditions.

Single-element rear wings are commonly used in sports cars and road cars where the emphasis is on a balance between performance and practical use. They are also seen in racing series with regulations that limit aerodynamic complexity, such as certain GT (Gran Turismo) classes.

Picture 1: Example of the airflow around a rear wing designed within the WTCC championship regulations

Multi-Element Rear Wings

Multi-element rear wings consist of multiple airfoil sections arranged in tandem. These sections work together to enhance the aerodynamic performance of the wing.

The primary advantage of multi-element wings is their ability to generate significantly more downforce compared to single-element designs. The multiple surfaces create more pressure differentials, enhancing lift (downforce). This results in improved control over the airflow, delaying flow separation and reducing turbulence, which enhances stability at high speeds. Additionally, the elements can be adjusted independently, allowing for fine-tuning of aerodynamic properties to suit specific track conditions and vehicle dynamics.

However, the complex design of multi-element wings can result in increased aerodynamic drag, which may reduce top speed. They are also more complex to design, manufacture, and maintain. These wings require precise adjustments and are often more expensive. Moreover, many racing series impose strict regulations on aerodynamic components, sometimes limiting the use of multi-element wings.

Multi-element rear wings are prevalent in high-level motorsport categories, such as Formula 1, Le Mans Prototypes (LMP), and certain classes in GT racing, where maximizing downforce is crucial for cornering performance. They are also used in time attack and hill climb competitions, where the emphasis is on achieving the highest possible downforce for maximum grip.

Picture 2 : Example simulation of the airflow around a rear wing of a Formula 1 car.

Aerodynamic Comparison

The physics of airflow around a wing is fundamental to understanding the performance differences between single-element and multi-element rear wings. When air flows over a wing, it splits into streams that travel over and under the surface. Due to the wing’s shape and angle of attack, the airflow over the top surface accelerates, reducing pressure according to Bernoulli’s principle. This pressure difference generates lift, or in the case of rear wings, downforce.

In single-element wings, the airflow is relatively simple, but there are limitations in how much downforce can be generated without increasing drag significantly. As the angle of attack increases to generate more downforce, the airflow can become turbulent, causing flow separation. This results in a loss of lift and a dramatic increase in drag, a phenomenon known as stall.

Multi-element wings, on the other hand, have multiple airfoil sections that interact to manage the airflow more effectively. The additional elements can re-energize the boundary layer (the thin layer of air close to the surface), delaying flow separation and reducing turbulence. This allows for higher angles of attack and greater downforce without the associated increase in drag seen in single-element wings. The interaction between the elements also creates complex flow structures that further enhance aerodynamic efficiency.

In terms of downforce generation, multi-element wings excel in creating higher levels of downforce. The interaction between elements creates a more significant pressure difference, enhancing lift and downforce. This makes them ideal for high-speed corners where maintaining grip is essential. Single-element wings, while effective, cannot match the downforce levels of multi-element wings but offer a more balanced performance with lower drag.

When considering drag characteristics, single-element wings typically generate less drag, making them suitable for tracks with long straights where top speed is a priority. Multi-element wings, while generating more drag, provide superior downforce, which can be crucial in tracks with tight corners and complex turns.

The flow behavior also differs between the two designs. Multi-element wings manage airflow more effectively, reducing turbulence and delaying flow separation. This results in more stable and predictable handling. In contrast, single-element wings may experience earlier flow separation, which can lead to less stability at high speeds, especially in turbulent conditions.

Regarding adjustability and versatility, multi-element wings offer greater adjustability, allowing for precise aerodynamic tuning to suit different track conditions. This makes them versatile for varying race environments. Single-element wings are less adjustable but are easier to set up and tune, making them practical for more straightforward applications.

Picture 3: The effect of the complex design of the multi-element in regulating the vortices

Picture 4: Wake development along the x and z axis of the Formula 1 wing

Regulatory Influence

The choice between multi-element and single-element rear wings is not solely based on aerodynamic performance; it is also heavily influenced by regulations. Motorsport governing bodies impose rules to ensure safety, fairness, and competition. These regulations can limit the number and configuration of aerodynamic elements, dictating whether teams can use multi-element wings or must stick to simpler, single-element designs.

For instance, Formula 1 regulations are very specific about the design and dimensions of rear wings to control the aerodynamic performance of the cars. In contrast, GT racing classes might have more restrictive rules to limit costs and maintain closer competition between different manufacturers.

Conclusion

The choice between a multi-element and a single-element rear wing depends on the specific requirements of the vehicle and the conditions it will encounter. Multi-element wings are the preferred choice in high-performance racing where maximum downforce and precise control over aerodynamics are critical. In contrast, single-element wings offer a simpler, lower-drag solution that balances performance with practicality, making them suitable for a wider range of applications. Regulations play a crucial role in determining which type of wing can be used, ensuring that the competition remains fair and within specified safety limits.

Understanding the aerodynamic principles behind these wing designs helps engineers and drivers optimize their vehicles for the best possible performance, whether on the track or the road.