A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across the body of a vehicle in motion, usually manifested as lift, turbulence, or drag.
An automotive wing is a device designed to generate downforce as air passes around it, not simply disrupt existing airflow patterns.
Front spoilers, found beneath the bumper, are mainly used to decrease the air underneath the vehicle to reduce the drag coefficient and lift.
This is because many cars have a relatively steep downward angle going from the rear edge of the roof down to the vehicle's trunk or tail, which may cause airflow separation.
[6][7] This feature was replaced and homologated in 1970 by AMC with a trunk lid-mounted oversized ducktail spoiler designed by Mark Donohue and Roger Penske.
In most cases, the spoiler deployment is achieved with an electric motor controlled automatically by the onboard computer or other electronics, usually based on vehicle speed, driver setting, or other inputs.
A spoiler that hides may be appealing to vehicle designers who are seeking to improve high-speed aerodynamics (for example, the Porsche 911 or Audi TT) without drastically changing its appearance.
Powered fans, such as in the Chaparral 2J, do the equivalent of spoilers and increase the downforce, hence the traction and handling of the vehicle (See ground effect).
The trailers they pull can also be fitted with under-side spoilers that angle outward to deflect passing air from the rear axle's wheels.
Its nose is specifically designed to spoil a wind effect associated with passing through tunnels, and it can deploy 'ears' that slow the train in case of emergency by increasing its drag.
The low pressure above this pocket will cause the flaps to deploy, and counteract some of the lift generated by the car, making it more resistant to coming out of contact with the ground.
[16][17][18] Designed to reduce rear-end lift and so keep the car from oversteering at high speeds,[19] the rubber edges of the whale tail spoilers were thought to be "pedestrian friendly".
[23] The Porsche 911 whale tails were used in conjunction with a chin spoiler attached to the front valence panel, which, according to some sources, did not enhance aerodynamic stability.
[24] It is less effective in multiplying downforce than newer technologies like an airfoil,[25] "rear wing running across the base of the tailgate window",[26] or "an electronically controlled wing that deploys at about 50 mph (80 km/h)"[27] The whale tail came on the heels of the 1973 "duck tail" or Bürzel in German (as a part of the E-program), a smaller and less flared rear-spoiler fitted to 911 Carrera RS (meaning Rennsport or race sport in German), optional outside Germany.