Copyright © A. Filippone (1997-2005). All Rights Reserved.

High-Lift Systems for Racing Cars


Listed below are a few major high-lift (e.g. downforce) devices. Most of the devices and technical solutions are often the results of the current regulations, and do not necessary apply to the latest designs.

Multi-Element Wings

Wing design is the most appropriate approach toward the improvement of the aerodynamic characteristics. Besides the wing the design there is often the opportunity to increase the downforce by using wings with several elements (2 in the Indy and Formula 1 front wing; 5 or more in a Formula 1 rear wing).

Indy Rear Wing
Figure 1: Rear Wing of Indy car (2-element)

The benefits of adding a trailing-edge flap, and possibly a leading-edge slat, are a well known problem in aeronautics. Wings with a larger number of elements, appropriately designed and placed, can provide even higher values of downforce (at the cost of a far higher drag).

The wings are rather short (they are said to have a low aspect-ratio), and three-dimensional effects (e.g. cross-flow velocities) act to reduce considerably the values of downforce predicted for the wing section. The problem is further complicated by the fact that the wing is usually working in a perturbed, turbulent and unsteady field.

Wing Endplates

End plates (side fins) are mounted on low aspect-ratio wings to reduce the three-dimensional effects on the wing, by creating a physical bound to the tip flow that would tend to spill from the pressure to the suction side of the wing. Their effect is a function of their size as compared to the wing size.

Some recent developments in Formula 1 have led to the introduction of intermediate fences on the lower side, whose function is to further reduce the three-dimensional effects, by creating a limit to the deviation of the boundary layer flow from the plane of symmetry.

Seals and Skirts

Seals and skirts have been introduced by Chaparral and Lotus, respectively. The idea behind this solution is that by sealing the gap between the underbody and the outer field, airflow leakage from the pressure side (outer field) and suction side (underbody) is prevented. Sealing skirts were widely employed in the late 1970s Formula 1 races.

Side pods

Large side pods increase the area on which the aerodynamic lift operates, and thus can yield larger values of downforce, besides working as safer shelter for the driver. Their effectiveness is considerable, with and without Venturi channels.

Venturi Channels

Simple fluid dynamics says that flow that accelerates looses pressure. This is in fact the nozzle effect (or Venturi effect), when flow in a convergent nozzle accelerates and looses pressure. Pressure is then recovered in the diffuser.

By shaping the underbody as an inverted wing, or with appropriate channels, or even with a simple scant angle that work with the Venturi effect, the overall pressure between the underbody and the ground decreases.

Other Devices

Here we list some other devices/solutions aimed at increasing the downforce. They include:

Gurney Flaps

These are small plates mounted vertically (or almost) at the trailing edge of the wing, in order to provide a further increase in downforce or lift. This is a good when a re-design of the wing is not affordable, or when drag is not an issue (or both).

Gurney Flap
Figure 2: Gurney flap

Spoilers and Dams

Spoilers and dams (front spoilers) are devices placed in the back and front, respectively, to increase the downforce (rear spoilers nowdays are common features also in production cars.)

The rear spoiler produces a deviation of the flow, so as to create a pressure increase in the rear deck, and hence the negative lift. It also promotes rear separation (e.g. drag), by creating an area of relatively flat pressure (wake).

Dams are front spoilers, generally placed under the nose of the car for lift and drag gains and for cooling airflow enhancement.

Body Work

The need for generating high values of downforce makes engineering go around the regulations. This sometimes produces details called body work, which are not simply cosmetic changes, but can make a difference of a few tens of a percent. Fig. 3 at right is an example of small wings placed ahead of the rear wheels of a 1997 CART Indy. Besides generating a little extra downforce, these wings works as to deflect the flow from the wheels.

Figure 3: Small Wings

Related Material

(on CD-ROM)
  • Multi-Element Wing Systems
  • Gurney Flaps

Selected References

  • Clancy JC. Aerodynamics, John Wiley, New York, 1975.

  • Schlichting H, Truckenbrodt E. Aerodynamics of the Airplane, McGraw-Hill, New York, 1979, Chapter 8 (Aerodynamics of the Flaps and Control Surfaces).
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Copyright © A. Filippone (1997-2005). All Rights Reserved.