Ride Height: Altering between Q and Race

McLarens Martin Whitmarsh spoke out at the Australian GP about the use of Ride Height Adjustments in between the qualifying and the race. Suggesting that several teams, one of which was Red Bull had such systems.
 
As I have previously explained ( http://scarbsf1.wordpress.com/2010/02/21/ride-height-changes-with-fuel-level/ ) the ban on refuelling creates huge weight differences between qualifying and the race (150kg), this alters ride height considerably (by F1 standards). Already running just 20-30mm off the ground the cars aerodynamics relies on a low ride height to create maximum downforce.  Equally having the ride too low height creates wear on the cars underbody skid-blocks set into the ‘plank’, if the wear is excessive the car will be excluded from the results. Furthermore Parc Fermé rule prevents the teams changing settings in between qualifying and the race, so teams need to find a compromise somewhere between set up for the light Q fuel or heavy race fuel. However, if a team were able to find a way to alter the ride height legally in between or indeed through the race then they could have ideal set up for each segment of the weekend. We know teams have ride height adjusters that can be adjusted at the pit stop, these tend not be used as they cannot be used until the first pit stop and with only one stop being the nor for the opening races it appears to be a ‘set up’ complication no one wants.   
 
 
Suspension set up

F1 cars suspension tends to adopt similar formats both front & rear and across the teams. Ride height and springdamping is provided by a pushrod (or Pull rod for Red Bulls rear suspension, which is the same but inverted) which operates a rocker, this rocker has levers operating the torsion bar spring, damper and third (or heave) damper. Ride height it set by the angle of the torsion bar on its splines and fine tuned by the shims in the pushrod.  Ride height does get controlled by the heave damper, but only when high aero loads compress the suspension at high speed, as the heave damper has some free travel before it starts to add stiffen the suspension it cant be used for adjusting static ride height. The individual wheel dampers do apply some pressure to the suspension when at rest, but aren’t commonly used for setting ride height. 

Mechanical solution

One solution put forward was a ratcheted system that keeps the ride height artificially low with a light suspension load and unlocks when the car is more heavily fuelled. I find this harder to believe as the suspension sees huge variance in load around the course of a lap, how it would identify the peak loads as being a heavy fuel load compared to say a bump makes the system hard to predict. Unless a solution that demands a suspension attitude that cannot be seen on track, such as raising both wheels to compress the heave damper car beyond normal limits to release a mechanism, this could possibly be done legally in the pit garage with the FIA’s knowledge. 
 
 
Repressurisation 
 
Another solution that seems altogether more feasible is the use of the gas charging cylinder within the damper. this cylinder normally acts to offset the motion of the damper rod inside the damper body. Charged with nitrogen, this does create some preload inside the damper. Teams are apparently allowed to recharge the nitrogen cylinder in Parc Fermé.  Its believed that if the team were able to over-pressurize the unit after qualifying with a low pressure, it would lengthen the damper, raise the ride height in order to offset the race fuel load.
One additional scenario with this set up, is the gas cylinder could be set up with a bleed valve, to allow a slow controlled pressure loss.  This would allow the suspension to lower through the race and the fuel is burned off. 
On paper this appears to be a perfect solution to the problem. 
 
 
 
 Cooling
One further theory is that the dampers are sensitive to temperature, for example cooler dampers could provide a lower ride height. Its possible to envisage a case where teams chill their dampers, again possibly the gas cylinder to reduce the volume of the gas to shorten the dmaper and lower the ride height before qualifying.  Then as the unit returns to ambient temperature the pressure increases and raises the ride height ready for the race. 
 
Over the course fo the Malaysian GP, we can expect to hear a lot of fuss about whether these solutions are being used.
However the potential of changing ride height for just the critical 3mm difference in between Q and the Race remains a technical challenge, but one well worth exploiting.
It is rumoured there are three possible solutions, although there may be more we have not heard of.

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