The mystery continues: almost every team in the paddock is convinced Red Bull has some sort of ride-height control that allows the RB6 to run low in qualifying to great aerodynamic benefit, while still being able to run with 150kg of fuel at the start of the race. Red Bull continues to deny it has any such thing.
Even if this column from the Bahrain weekend played a part in propagating the idea of such a system on the Red Bull, I personally believe the team. I don't believe it's running a 'system', an ingenious linkage or use of gas temperature etc. And yet the pattern of the car's performance - merely competitive in the long runs and race laps, but devastating during low-fuel qualifying - paints what seems a convincing picture of the car's uniqueness.
Here's another theory: consider that the RB6 has that unique (apart from the 'related' Toro Rosso) pull-rod rear suspension. Most rival teams were surprised that Red Bull had retained such a system when designing a double-diffuser car from scratch - as opposed to adapting a single-diffuser car, as had been the case with the RB5.
Sebastian Vettel © LAT
The low-mounted suspension rockers of a pull-rod system are in just the wrong place to allow the ultimate dimensions for a double-diffuser layout. Granted, having the rockers down there means they are no longer in the way of the upper body airflow where the sidepods meet the rear wheels - giving you a much cleaner flow to the rear wing and beam wing.
But the belief of the other teams was that there were more gains to be had from the diffuser shape than losses incurred by the blockage to the upper body.
Maybe. But consider a car that has a greater proportion than the others of its total downforce derived from the wings and other upper body devices. It may lose out to them in its peak downforce, but what downforce it has will be less sensitive to ride height, because it is underbody downforce that increases so much when you run the ride height low, not upper body.
If the RB6 is not relying as much as the others upon underbody downforce, it will not lose as much when it is running with a big ride height. It would retain a greater proportion of its peak when run in such trim. It may well even have significantly more total downforce than them when all are running a big ride height - as in current low-fuel qualifying - because it always has more upper-body downforce and it's hanging onto more of its underbody downforce.
Consider also that the more conventional double-diffuser/pushrod cars tend to have very extreme diffuser configurations - such as that on the McLaren that uses most of the width of the beam wing's underside as a diffuser exit ramp. Such arrangements make it very difficult to prevent the airflow stalling when the ride heights are big, especially at low speed.
A more conservative diffuser shape - such as that forced upon the Red Bull by the suspension layout - will be less prone to stall, even if it produces less peak downforce. It will deliver workable downforce over a wider range than a more extreme diffuser shape - and the shortfall in that can at least partly be made up by the greater upper-body downforce the suspension layout allows.
So it would make perfect sense that the Red Bull's advantage over the others is greater in qualifying, when the ride heights are artificially big, than at any other time during the weekend. It would also make sense that a car like the McLaren is much more competitive when fuel-laden than when empty - because its hyper-sensitive diffuser will be less prone to stall then.
As teams with conventional cars now look to designing 'systems' to compete with the Red Bull, so Red Bull would be understandably very reluctant to accept them - if its advantage genuinely stems from the basic layout of the car rather than a trick system.