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The Front Wing Assembly

The front wing assembly is constructed of carbon fiber and is the first part of the car to meet the air mass. The flow field here is better than at other parts of the car because the air here has been disturbed the least. The wing is designed to produce downforce and guide the air as it moves toward the body and rear of the car. Flaps and winglets may also be used to guide the air past the wheels to the radiator inlets and underbody. The turbulent air moving toward the rear of the car will impact the efficiency of the rear wing. The efficiency of the wing is based on the following:

  1. The Aspect Ratio:
      The amount of downforce produced by a wing is determined by its size. The larger the wing the greater the downforce. The length/width ratio is called the aspect ratio. The higher the aspect ratio, the more efficient the wing. The higher the aspect ratio, the less air resistance created by the vortex at the wing tips. The aspect ratio is the span of the airfoil (the long dimension perpendicular to the airflow) divided by its chord (the dimension parallel to the airflow).
  2. The Angle of Attack:
      The efficiency of a wing is its downforce/drag ratio. The amount of downforce generated is dependent upon the angle or tilt of the wing. The greater the angle of attack, the more downforce generated.
  3. Drag:
      While increasing downforce a wing also increases unwanted drag. Drag increases with the angle of attack. The downforce generated by the wing works in a vertical, downward direction, while drag acts in the opposite direction to the airflow.

In setting up the front wing assembly, engineers must consider what happens to the airflow as it travels toward the back of the car. In an effort to clean up the disturbed airflow, small adjustments are made to the front of the car. Turning vanes are used to deflect the turbulent flow wake away from the inside of the front wheels and front wing. This in effect forces disturbed air away from the underbody tunnels. Small vertical wing sections mounted on the front wing assembly are used only on the streeet and road setups. This would not be efficient on the speedway configuration, due to the increase in drag at higher speeds. The front wings on the speedway setup are very small and function as trimming devices rather than creating downforce. The front wing assembly (road course setup) is capable of producing 1500 lbs. of downforce.

The front and rear wheels create the greatest source of drag on the Indy car. This can account for up to 60% of the aerodynamic inefficiency of the car. The front wing assembly has end plates attached at 90 degrees to the end of the wings. The end plates help reduce turbulence around the front wheels and assist airflow moving to the radiators and around the sidepods. Any change made to the front of the car will affect the airflow moving toward the rear of the car. The team engineer must consider how any change to the front of the car will impact the overall aerodynamic efficiency of the car. Dave Keenan (Computational Fluid Dynamic project head for Rahal/Hogan Racing 1992) explains: "The car itself is an integrated system. If you change a front wing, you change the airflow to the sidepods and radiators. If you do something with the front tires, you change the airflow to the body and rear wing." The aerodynamic setup of the car has been refined to the point that minute changes to the front wings can improve the "ground effects" of the car. Air directed under the chassis creates an area of low pressure between the underbody of the car and the racing surface. The car is basically sucked down to the road which results in higher cornering speeds.

Return to Aerodynamics In Car Racing
Next page: The Chassis

Author: Bryan Yager, Ralston Middle School, Belmont, CA (12/94)

Curator: Jill Dunbar
Last Update: August 27, 2001
NASA Official: Walt Brooks