The width of a wing is known as its span, and the ratio of span to chord is the aspect ratio. Aircraft generally have high aspect ratios while racecars, especially single seaters, have very low aspect ratios. The angle of attack of a wing is the angle between the freestream airflow and the wing’s chord line. It is tempting sometimes to think of the airflow approaching a racecar wing as being horizontal, parallel to the ground. This may be true of front wings (although not necessarily), but is almost certainly never true of a rear wing. Hence, the flow onto a wing may be at an angle that is locally different from parallel to the ground. It has to be admitted that for convenience, racers often quote wing angle relative to horizontal simply because it’s easier to make measurements that way, but it pays to keep in mind that the airflow onto a wing is rarely parallel to the ground. Racecar wings are no longer allowed to have adjustable angle while on the move in most competition categories, Changes to angle may generally only be made in the pits or paddock. Jim Hall’s Chaparral 2E and 2F in 1966 and 1967 had variable angle rear wings, which were adjusted by the driver via a third pedal (the cars had auto transmission).