The big mystery of this season has been how the Ferrari can be a second off the pace in qualifying and only a tenth of a second or two off it in the race. I think I've figured out what the problem is.

It is a rear wing and diffuser problem, but it's a little complicated to explain, so bear with me.

In qualifying, the DRS overtaking aid can be used all the time. A driver comes off a corner and opens the DRS as soon as possible, reducing the drag and the wing wake, which gives extra straight-line speed.

As the car goes faster, the rear gets closer to the ground and that 'stalls' the diffuser, which is the underfloor which curves upwards at the back of the car. 'Stalling' means the airflow is not attached to it any more, and that reduces the downforce it produces.

When the driver brakes for the next corner, the car changes attitude - the rear comes up.

I am 99.99% sure that at that time, on the Ferrari, the diffuser does not re-attach immediately.

Because of that, the airflow at the back of the car is different, so the rear wing does not re-attach either.

So on initial corner entry, 18 or 20 times a lap in qualifying or whatever, the rear of the car has less downforce and therefore is unstable for a given amount of time until the diffuser and rear wing re-attach.

This rear instability on corner entry is what the Ferrari drivers are complaining about.


To reduce rear instability, you run less front downforce, but that gives understeer - less front grip - when the diffuser re-attaches. As it happens, less front wing also means less overall downforce.

The braking duration for a lot of these corners will be about a second. If the diffuser is not re-attaching for 0.2-0.3secs, that is a problem.

In the race, though, the DRS can only be used in specified zones and when the driver is within a second of the car in front.

So during the race on the non-DRS straights the diffuser will still stall but the rear wing is still working, which means when the driver brakes the diffuser re-attaches more easily. So in the race the driver has rear stability other than when he is braking after using the DRS.

That means in the race the Ferrari is more consistent.

You'll probably find that the stall-point on the diffuser in the race is at a lower ride-height (a higher top speed) than in qualifying, when it will stall earlier because the DRS is open on every straight.

So my suggestion to Ferrari would be to have a slightly less aggressive DRS system. They have one of the biggest gains in top speed when the DRS is open compared to when it is closed. I would reduce that a bit but make sure the rear-wing airflow is a bit more robust.

With the resources Ferrari have, that is something they could do very quickly if they got on with it - certainly in time for the next race.

They are using four or five rear wing designs and chopping and changing between them, so they are going round and round the problem but not actually fixing it.
This lack of consistency may also explain why Alonso was not able to improve on his final run in qualifying last weekend.

He made a point in Abu Dhabi of saying the fact he did the same lap time on three different runs in qualifying meant he had got the most out of the car.

Normally, that would be wrong - a driver should improve on his final run because up until then it is all about 'banker' laps. He should save the 100% on-the-limit lap until the end. Also, in Abu Dhabi the ambient temperature was dropping all the time as night fell and that would give more engine power.

But perhaps the instability at the rear of the Ferrari limits its potential.

The driver can only increase his effort level if he has the confidence to do so. If he doesn't have confidence on the corner entry, then he's stuck. The driver can't go quicker because he is at the limit of what the car will respond to.

The contrast with the Red Bull is interesting - Vettel nearly always goes faster on his final qualifying run. But while that car moves around and needs a lot of driving, it does respond to extra effort from the driver without doing anything nasty.

That means it is predictable, gives the driver confidence and the driver can find a tenth of a second or two.

So it was very instructive to see that on a weekend when Vettel missed nearly all of final practice, he not only did not get pole, but he also was beaten by Webber. He didn't have the confidence in the car he normally does.

That's a problem Alonso is probably facing every weekend.