A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag. Spoilers on the front of a vehicle are often called air dams. Spoilers are often fitted to race and high-performance sports cars, although they have become common on passenger vehicles as well. Some spoilers are added to cars primarily for styling purposes and have either little aerodynamic benefit or even make the aerodynamics worse.
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The term "spoiler" is often mistakenly used interchangeably with "wing". An automotive wing is a device whose intended design is to generate down-force as air passes around it, not simply disrupt existing airflow patterns. As such, rather than decreasing drag, automotive wings actually increase drag.
Operation
Since spoiler is a term describing an application, the operation of a spoiler varies depending on the particular effect it is trying to spoil. Most common spoiler functions include disrupting some type of airflow passing over and around a moving vehicle. A common spoiler diffuses air by increasing amounts of turbulence flowing over the shape, "spoiling" the laminar flow and providing a cushion for the laminar boundary layer. However, other types of airflow may require the spoiler to operate differently and take on vastly different physical characteristics.
Passenger Vehicles
The goal of many spoilers used in passenger vehicles is to reduce drag and increase fuel efficiency. Passenger vehicles can be equipped with front and rear spoilers. Front spoilers, found beneath the bumper, are mainly used to decrease the amount of air going underneath the vehicle to reduce the drag coefficient and lift.
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Sports cars are most commonly seen with front and rear spoilers. Even though these vehicles typically have a more rigid chassis and a stiffer suspension to aid in high-speed maneuverability, a spoiler can still be beneficial. This is because many vehicles have a fairly steep downward angle going from the rear edge of the roof down to the trunk or tail of the car which may cause air flow separation. The flow of air becomes turbulent and a low-pressure zone is created, increasing drag and instability (see Bernoulli effect). Adding a rear spoiler could be considered to make the air "see" a longer, gentler slope from the roof to the spoiler, which helps to delay flow separation and the higher pressure in front of the spoiler can help reduce the lift on the car by creating down-force. This may reduce drag in certain instances and will generally increase high-speed stability due to the reduced rear lift.
Due to their association with racing, spoilers are often viewed as "sporty" by consumers. However, "the spoilers that feature on more upmarket models rarely provide further aerodynamic benefit."
Material types
Spoilers are usually made of lightweight polymer-based materials, including:
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ABS plastic: Most original equipment manufacturers produce spoilers by casting ABS plastic with various admixtures, typically granular fillers, which introduce stiffness to this inexpensive material. Frailness is a main disadvantage of plastic, which increases with product age and is caused by the evaporation of volatile phenol s.
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Fiberglass: Used in car parts production due to the low cost of the materials. Fiberglass spoilers consist of fiberglass cloth infiltrated with a thermosetting resin, such as epoxy. Fiberglass is sufficiently durable and workable, but has become unprofitable for large-scale production because of the labor involved.
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Silicone: More recently, many auto accessory manufacturers are using silicon-organic polymers. The main benefit of this material is its phenomenal plasticity. Silicone possesses extra high thermal characteristics and provides a longer product lifetime.
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Carbon fiber: Carbon fiber is lightweight and durable but also expensive. Due to the large amount of manual labor, large-scale production cannot widely use carbon fiber in automobile parts currently.
Racing Vehicles
While a mass is traveling at increasing speeds, the air of the environment affects its movement. Spoilers in racing are used in combination with other features on the body or chassis of race cars to change the handling characteristics that are affected by the air of the environment.
Often, these devices are designed to be highly adjustable to suit the needs of racing on a given track or to suit the talents of a particular driver, with the overall goal of reaching faster times.
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| Courtesy of carbiketech.com |
