A necessity in F1: the wind tunnelA modern bespoke wind tunnel is a necessity rather than a luxury in Formula 1. Such is the intensity of competition at motorsport’s top level, that a 10 percent improvement in the complex and highly-sophisticated relationship between downforce and drag on the wings of a Formula 1 car will translate into a one-second improvement in lap time.
Vodafone McLaren Mercedes has a fully enclosed wind tunnel at the McLaren Technology Centre, which has been built exclusively for the team’s use and has been operational since 2001. The building is an acoustically sealed block with two walls linked to the structure by rubber mounts to minimise noise break-out and vibration.
The 145 metre tunnel, in the shape of a rectangular circuit is located within the building and the air is driven by a giant fan which is four metres in diameter and rotates at up to 600 rpm.
OperationOnce air is circulating in the tunnel, it goes through a whole series of conditioning processes to ensure that by the time it reaches the test chamber it is flowing steadily and uniformly, guaranteeing consistent and accurate results.
After first being slowed down, simply by being fed into a wider section of the tunnel, it then enters the stilling chamber, where a mesh screen takes out some of the turbulence.
Next, it is forced through a honeycomb to straighten it out after which two further screens remove any remaining turbulence.
From the stilling chamber it flows into the contraction chamber where it is compressed to increase the velocity and iron out any boundary layer effects before it enters the test cell in pristine condition.
Aerodynamic TestingAs well as testing new development parts for the cars, Vodafone McLaren Mercedes also maps its aerodynamics in the tunnel.
Different wing angles and set-ups are needed for different race tracks and all have to be tested, with tables of aerodynamic data built up for the race team’s use. They relate to a myriad of changeable areas – flap, angles, rear wing angles, cooling options, brake ducts, bodywork exits and so on.
The 50% scale model of the car which is used in the wind tunnel is made from carbon fibre and modelling block and is attached to a support strut, through which it is connected to a mechanism that can control its pitch and ride height to an accuracy of 0.01mm.
Creating an aerodynamic map to be used to develop the settings for each race allows the precise balance between drag and downforce to be determined according to which circuit the car is being prepared for.
Facts & Figures
- Using 400 tonnes of steel between 8-10mm thick, the wind tunnel’s construction was the equivalent of building a fairly large ship.
- It is 145 metres long and six metres square at its widest point.
- The air is driven round by a giant fan, four metres in diameter, which rotates at up to 600rpm.
- The fan sucks in air from outside in such volume and at such a rate (15 cubic metres per second) that if the building were sealed, the walls would implode.