Wheel spat how to#

Whether wheel spats can bring a sizeable car efficiency improvement, I can't tell (in the Citroen car design - DS, GS, CX, it has always been an integral part of the design). Drag reduction has always been an engineering 'obsession' for mobility (whether in air, on road or in water), nowadays for individual sport performance, etc.ДЄerodynamic experts excel in always findings new ways to reduce drag by abating back turbulences and vortices, and that's good. It brings me back to my (old time ) engineering studies: turbulent flows, Bernoulli's equation, C-drag factor, etc.ДЄ couple of decades ago, Citroen has named one of its 'revolutionary' car 'CX' making reference to this drag C-coefficient. Wrt car efficiency, drag reduction was, is and will remain welcome. In cars, the symmetry is broken by the cavity overpressure and the heat generated by the braking system can therefore be evacuated effectively (as the speed of the outer part of the wheel is higher than near the axis), with the inner fairing reducing the drag created by the inner part of the struts.ДЄs in many real-life problems, the solution of a multi-parameter problem is seldomly the ideal solution for a single parameter (like would be a lenticular wheel) but more frequently a smart combination of all solutions. In order to reduce the wheel drag, the most efficient designs seem to use a partially covered wheel fairing with outbound oriented struts.Д«icycles used in the Tour de France race against time sometimes use lenticular wheels, but in this case, the pressure field is symmetrical. There are multiple inputs including some far away from the aerodynamics (like accumulation of snow or braking system wearing due to high temperatures). The aerodynamics of the automotive wheel is pretty more complex than what can be assumed at first sight.

Air inlets were used to keep the rear tires and brakes cool and within their operating temperature ranges, while air outlets were used to reduce unwanted high pressure that could cause tire blowouts in long endurance races.

Wheel spat how to#

It was found how to overcome the challenges associated with the use of spats. This phenomenon reduces the air pressure beneath the car and creates downforce, also known as negative lift (4). The spats in the case of this car helped to maximize the Venturi Effect. The Jaguar XJR-9 (Figure 7), for example, was one of the most effective uses of wheel spats, winning at both Daytona and Le Mans in 1988. However, car designers were able to deal with this issue. This will lead to an increase in the pressure of the tire itself and there is a danger of a possible blow-out when normal operating pressure is exceeded. Friction between the tire and the road produces heat, which heats up the accumulated air in the wheelhouse. Any air that does make its way under the spat and into the wheel arch is effectively trapped there. It was clear that spats were more suitable for rear wheels, but using spats had another adverse effect.