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Technical Glossary

Aerodynamics. The study of the interaction between air and the solid bodies moving through it. See The Aerodynamic Development of the Formula One Car.

Aerodynamic force. The force created by a vehicle's movement through the air. It is the combination of aerodynamic drag and aerodynamic lift.

Aerofoil or Airfoil. An aerofoil is the shape of the cross-section of a wing. But in motorsport it is usually regarded as just another word for a wing.

Angle of attack. The angle between an aerofoil's chord line and the airflow.

Anhedral. The angle between an aerofoil and the horizontal when the wing is inclined downwards from its mounting.

Apex. The inside part of a corner that is on the racing line.

Boundary layer. A layer of static to slow moving air adjacent to the surfaces of a moving body. Friction between the body and the surrounding air holds back the flow nearest the surfaces, whilst the air further from the body in the mainstream flows past at unabated speed.


+ An aerofoil with one surface (top or bottom) curved more than the other side is said to have camber.
+ Tyre camber is the amount that the top of the tyre leans into, or away from the car.
+ Track camber is the horizontal angle or curve on a track surface.

Centre of pressure. The point at which the aerodynamic forces on a body appear to act, and at which there is no aerodynamic movement. It is similar the centre of gravity in mechanical terms.

Chord. The distance between an aerofoil's leading edge and its trailing edge.

Chord line. A line joining the leading edge to the trailing edge.

CD Abbreviation for drag coefficient.

CL Abbreviation for lift coefficient.

CP Abbreviation for pressure coefficient.

Differential. A set of mechanical gears that eqaulises the power between the left and right drive wheels, particularly when cornering, when the outside wheel travels further than the inside wheel.

Diffuser. The divergent (expanding) section of a duct which slows down airflow to reduce pressure loss. On an F1 car it is an upswept panel at the rear of the underbody.

Downforce. The opposite of aerodynamic lift, sometimes referred to as negative lift. The force caused by the air over the wings to push the car into the ground, increasing grip and cornering speeds.

Drag. That component of the aerodynamic force which is parallel to, but opposes the movement of, a body through air.

Drag coefficient. A dimensionless value that allows the comparison of drag incurred by different sized and different shaped bodies.

FIA. The F?d?ration International d'Automobile, the ruling body of world-wide motorsport based in Switzerland.

Fluid. Usually a gaseous or liquid substance which is capable of flowing. Air is fluid under normal conditions.

Frontal area. Generally taken to be the area of the front view 'silhouette' of a vehicle, though sometimes simplified as width multiplied by height.

G-Force The apparent increase in weight of an object due to gravitational forces. Centrifugal force is a type of g-force which keeps your clothes stuck to the outside of a spinning washing machine! In racing cars, it is the force pulling the drivers head to one side as the car corners.

Ground effect. The aerodynamic modification of the airflow beneath a vehicle caused by its close proximity to the ground. This increases the speed of the airflow, and reduces the pressure due to Bernoulli's principle. All cars operate in ground effect, though not all exploit the effect beneficially.

Launch control A form of traction control used at the start of the race for the best get-away. Parameters include start-finish line gradient, starting line grip, distance to first corner and clutch biting point.

Lift. That component of the aerodynamic force which is perpendicular to the direction of a body's travel, directed vertically upwards or downwards (negative lift).

Lift coefficient. A dimensionless value that allows the comparison of lift incurred by different sized and different shaped bodies. A positive lift coefficient represents lift, whilst a negative lift coefficient represents downforce.

Line. See racing line.

Loose. See oversteer.

Mainstream. That part of the airflow around a body which is far enough away to remain undisturbed by the body's passage. Thus the mainstream velocity is equal and opposite to the body's velocity.

NACA. National Advisory Committee for Aeronautics, the predecessor of NASA. Among other things, the NACA catalogued a vast number of aerofoil profiles.

Oversteer. Occurs when the wheels are turned, and the car does not turn at the same rate. Causes the rear of the car to take a wider apex, causing the car to spin in extreme conditions. Also called loose in the US.

Pitch. The motion of a vehicle in which the front moves up and down relative to the static position.

Pitch sensitivity. The magnitude of aerodynamic downforce can markedly alter with changes to front ground clearance as a result of pitch movements. This can affect the vehicle's performance and 'feel'.

Pressure coefficient. A dimensionless value which acts as a means of indicating the local pressure at some point of interest around a body, and which is independent of velocity.

Push. See understeer.

Racing line. An imaginary line around a circuit that provides the quickest lap time. When turning into a right-handed corner, the quickest line is to enter on the left side of the track, turn in and 'touch' the apex and ease back out to the left side of the track. Opposite for left-handers.

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Ride height. Synonymous with ground clearance, the ride height can be taken as the size of the gap between a vehicle underside and the ground.

Roll Caused when cornering. As a car negotiates a left hand bend, the car leans to the right due to g-forces. Also called body roll.

Rollbar A mechanical link between the left and right suspension components, to equalise wheel travel on both sides. A soft rollbar decreases understeer, decreases cornering speed, but preserves the tyres.

Skirt. A device for bridging the gap between a vehicle's sides and the ground for the purpose of controlling the airflow under the car, and sealing it from the flow outside. Pioneered by Lotus in 1978, but now banned. See aerodynamic essay for development information.

Splitter. A generally flat, horizontal, forward-protruding extension to the underbody.

Streamlined. Having a smooth even shape that offers the least resistance to movement through the air

Traction control. A means of electronically reducing the power to the driving wheels, to minimise wheel-spin, and maximise traction. This is usually done by matching the speed of the rear wheels to that of the front wheels by reducing the voltage to the spark plugs.

Tight. See understeer.

Underbody. General term for the underside of a competition car.

Understeer. Occurs when the wheels are turned, and the car does not turn at the same rate. Causes the front of the car to take a wider apex than the driver's steering lock requires. Also called push, or tight in the US. Can be corrected by adding more front downforce, sofening springs and rollbar, or reducing front tyre pressure. Extreme conditions cause a car to go straight on instead of turning for a corner.

Vortex. A rotating motion in a parcel of air. Can be seen as 'whisps' of air coming from the top, outer edge of the rear wing in humid conditions.

Wing. In motorsport, a synonym for aerofoil. Shaped like and aircraft wing, and attached to a sprung part of the car upside-down for creating downforce and displaying sponsors names!
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Last modified: 7 Jun 2005 - 19:46:37
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