The first small-track racing car to use a wing was driven by Jim Cushman at Columbus Motor Speedway in Ohio in 1958, with the wing fabricated by Gene and Floyd Miller. The innovation spread quickly; by 1959, as many as half the field at Columbus was running with wings. During the early 1970s, sprint car drivers began fitting wings with vertical sideboards to both the front and top of their cars. The combination of the horizontal wing surface and the perpendicular sideboards at the wing's lateral edges proved effective at generating downforce and also at redirecting airflow to assist cornering on short ovals.
The top wing on a sprint car is a large, roughly rectangular flat or lightly cambered surface positioned high above the driver. It spans the full width of the car, with vertical sideboard panels extending downward from both lateral edges. These sideboards serve a dual function: they increase the effective aerodynamic surface area and, by directing airflow, help the car rotate through corners on a dirt oval, where the grip mechanics differ substantially from paved road racing.
The downforce generated by the top wing presses the car into the track surface, improving traction. On dirt tracks in particular, where the surface is loose and grip varies substantially depending on moisture content, prepared clay composition, and how much rubber has been laid down through an event, the additional mechanical grip provided by the wing's downforce is critical to maintaining control at the speeds sprint cars achieve. Sprint cars weigh approximately 1,400 pounds including the driver and produce more than 900 horsepower from 410-cubic-inch naturally aspirated V8 engines, yielding a power-to-weight ratio that exceeds contemporary Formula 1 cars; without the wing's downforce managing that power, maintaining traction would be far more difficult.
Beyond aerodynamic performance, the top wing also serves an important safety function. The substantial downforce it generates reduces the likelihood that the car will become airborne in the event of contact or a loss of control. When a winged sprint car does go airborne, the wing typically contacts the ground first and breaks off or crumples under impact, absorbing energy and lessening the forces transmitted to the driver and chassis. This crumple behavior makes the wing a sacrificial safety structure as well as an aerodynamic device, and teams are often able to replace a damaged wing during a caution stoppage and continue the race.
Wingless sprint cars, which represent the traditional form of sprint car racing dating back to the 1930s and 1940s, run without either the top wing or front wing. Though their chassis often include mounting stub-outs in the frame to permit wing attachment, they race without downforce. The relative lack of aerodynamic grip creates markedly different driving characteristics from winged cars, demanding different throttle and steering inputs through corners, and is considered more challenging by many participants. Wingless cars are also more prone to becoming airborne in accidents, since the downforce protection of the top wing is absent. Both configurations remain active in competition, governed by different sanctioning bodies and track programs throughout the United States, Australia, New Zealand, and South Africa.
When Ted Johnson founded the World of Outlaws in 1978 as the national promotional body for winged sprint cars, the top wing had already become standard equipment in that class. The World of Outlaws, racing from February through November across the United States, established the winged 410-cubic-inch sprint car as the dominant form of the sport. Cars in the series run 15-inch-wide right rear tires and mechanical fuel injection on methanol, with no electrical starter — requiring push starts from a truck or quad before each heat and feature race. The top wing's aerodynamic contribution is integral to the performance envelope these cars achieve, with top speeds on faster tracks exceeding 160 miles per hour.