IST eight-post racetrack rig at McLaren Racing sits at eye level, supported by an 80 tonne seismic base on isolation mounts.
Controlling downforce simulation is the critical factor and this is expressed as the RMS (root mean square) and the phase shift accuracy of the rig. In practice, IST produced a rig that was three times more accurate than the target figures. This was achieved by changes to the mechanics and hydraulics of the actuators, reductions in friction, improved compliant links (rubber bushes) between the actuators and the chassis and an advanced closed loop control technique.
To illustrate the aerodynamic forces involved, typical Formula 1 racecar ground clearances of 40mm (front) and 80mm (rear) can be reduced to virtually zero at maximum speed (about 220mph).