2018 Regulation Rear Wing

The old regulation rear wings were introduced in 2009 as a series of aerodynamic changes aimed to increase downforce and improve overtaking opportunities by simplifying the aerodynamics of the cars. The wing is designed tall and narrow, significantly altering the aerodynamic profile of the cars.[18]  

Wing Shape and Components

The aerodynamic elements of a formula one car are continuously evolving. The rear wing has undergone substantial changes over the years, with engineers constantly pursuing ways to enhance and improve its functionality. Prior to the regulatory modifications in 2022, the rear wings were comprised of several key elements. 

Figure 4 – CAD design of a rear wing [22]

Mainplane: This is the largest rearward-angled component spanning the full width of the car. 

Flaps: These are smaller horizontal components attached to the endplates that are adjustable to allow for teams to modify them to optimise performance depending on the track. When the flap is positioned downwards (closed), it amplifies the downforce produced by the wing and consequently increases the cars grip and speed. Conversely, when the flap is tilted upwards (open), it diminishes the downforce and reduces the drag resulting in more top end speed.[19]

Gurney flaps: These are short vertical tabs located at the trailing edge of the rear wing. Their function is to enhance the wings efficiency by increasing the strength of wingtip vortices. Enhancing the pressure difference between the upper and lower surfaces, gurney flaps mitigate turbulence and drag, delaying flow separation. These simple passive flow devices can significantly increase downforce with minor changes in drag and stall angle.[20] 

Endplates: Found on both sides of the rear wing, these vertical aerodynamic plates are positioned at wing tips and are attached to the main wing. They play a crucial role in managing airflow and controlling vortices around the wing, helping to minimise turbulence and drag. Additionally, the endplates prevent airflow from spilling off the sides of the wing, thereby maintaining efficiency. 

DRS: This refers to the hydraulically activated mechanism that adjusts the flaps to reduce drag down straight-line sections of the track. When engaged, the rear wing flap opens, allowing air to pass through it rather than pushing down on the wing.[21] This leads to a reduction in downforce and enabling the car to achieve higher speeds. 

All these components function synergistically to maximise the aerodynamic performance of the rear wing. As shown in figure 4 which includes all key components to the old rear wing design.

Vortices

A vortex is a region of fluid characterised by its rotation around a core of low pressure.[23] The air pressure in a vortex is lowest in the centre and rises progressively with the distance from the centre. This is in accordance with Bernoulli’s principle [24] and shown in Figure 5. This principle states that as the speed of a fluid (gas or liquid) increases, its pressure decreases, and vice versa. This principle is based on the conservation of energy, which states that the total energy of a system remainsconstant.[25]

Figure 5 – Bernoulli’s principle [26]

Two or more vortices that are parallel and circulating in the same direction will merge to form a single vortex. The circulation of the merged vortex will equal the sum of the circulation of the constituent vortices.[24] Vortices are a byproduct of producing aerodynamic lift or downforce, originating from the circulation of a bound vortex, where the circulation is proportional to the lifting force. To maintain balance, the bound vortex has a counter-rotating counterpart, known as the shed vortex. The shed vortex, along with the trailing vortices, form a vortex ring as the air from the high pressure side spills over to the low-pressure side. A downforce generating wing, such as rear wings in F1, have the opposite circulation (negative lift) to lifting wings, so the vortices rotate in the opposite direction. The tip vortices rotate with centreline up wash. 

Tip Vorticities create significant drag on high-lift (or downforce) wings. This is known as induced drag, which is inversely proportional to the aspect ratio of the wing. The aspect ratio of an F1 rear wing is around 2.7, this was raised to 3 following a 2019 rule change. This is extremely low.[27] Formula one cars have the power to overcome the drag penalty from the rear wing vortices, as the increased downforce is typically more beneficial to overall lap time. On circuits that demand high downforce and higher lift-to-drag ratios, such as Spa, Azerbaijan, or Canada, teams frequently use a spoon or bucket-shaped wing. These wings feature reduced camber, incidence, or both at the outer edges compared to the centreline.[24]

The main vortex generated by the rear wing is the wingtip vortex, which forms at the junction between the endplates and the wing tip. At this point, high pressure airflow spills into the low pressure area, creating an anticlockwise vortex. This phenomenon is an inevitable side effect of three-dimensional downforce generation. Since pressure is a continuous function, it must equalise at the wing tips. Consequently, air particles tend to move from the lower pressure surface around the tip to the higher-pressure surface, ensuring pressure equilibrium across the wing.[27]

The rear wing also generates a secondary vortex known as the underwing vortex. This occurs when low-pressure airflow beneath the wing merges with ambient pressure flow outside the endplates at various points along the trailing edge of the wing. This vortex, like the wingtip, rotates anticlockwise. The underwing vortex significantly enhances downforce and consequently drag. Downforce is increased as the vortex accelerates the flow velocity beneath the wing, further reducing pressure and increasing the pressure differential, which in turn raises induced drag.[23]

Vortices, although typically associated with drag, can also be utilised to generate lift. This is demonstrated with a slender delta wing, shown in Figure 6, where lift is produced by two strong leading-edge vortices forming along its sharp edges. According to the Bernoulli equation, the highspeed vortices reduce pressure, resulting in increased lift through a suction effect, demonstrated in Figure 7. This principle is applicable to Formula 1 rear wing, where the rotation of the vortex is altered to generate downforce instead.[28]  

  Figure 6 – Delta wing vortices [28]

Figure 7 – Delta wing pressure distibution (suction effect at the tip) [28]

These vortices, although unavoidable, can be beneficial. Due to their high energy, vortices can prevent early flow separation. The high-energy flow moving across the boundary layer imparts more momentum, enabling it to follow the curvature of the object. This keeps the airflow attached for a longer duration, thereby reducing the risk of aerodynamic stall.[29] 

Issues and Problems

substantial turbulent air for trailing vehicles. This turbulent air becomes trapped in the front wing of the following car, resulting in instability.[30] Empirical data indicates that this disturbed air causes a downforce reduction of 35% at a distance of 20-meters and 46% at 10-meters.[10] This consequent reduction in downforce diminished grip on the track and impairs the handling of the car, posing a major issue in F1 as it heavily effects overtaking. When a car is subject to ‘dirty air,’ its performance drops slightly, making it harder to close the gap with the leading car and thereby limiting passing opportunities. This can lead to what’s known as a ‘train’ of cars unable to pass one another.[31]