I noticed at Jerez; McLaren and Renault have joined Ferrari, Toyota and Williams in running the static front wheel covers...
Here's some quotes I've taken in the past few weeks from the teams TDs on the wheel fairings.
Pascal Vasselon
"We call them ‘Rim blankings’, honestly the effect of the front wheel blanking is not something you can capture very simply. We have now some experience with it, very clearly it can have totally different effect according to the rest of the flow structure over the rest of the car. It’s a powerful item, you can use it in different ways. Its not only a drag reduction item and really can change a lot of things in terms of front wheel wake. You are of course playing with the font wheel wake
It requires careful tuning according to the rest of the car, the first time we ran it on the TF108 concept it was not working, now it has started to work. That’s just to illustrate that it is something which easily interacting with the rest of the car. Its not just something you put on the car and gain a couple of points of drag, its much more complex than that.
It affects the brake cooling, You need to step up the brake cooling, in our case its not been a problem because we were not really marginal on brake cooling and adding some brake cooling was not really detrimental in terms of aero efficiency. But yes it does affect the requirement in terms of brake cooling and it can have an effect in some cases on effect on yaw\steer sensitivity.
It requires a very interesting design in terms of the extension of the front hub, with of course the rotation of the wheel and not the rotation of the rim blanking. From the outside we are quite happy the way we have done it. "
Sam Michael
"They very complicated actually, we were running them in testing last week at Barcelona. We did plan to take them to last couple of race, but we had problems, not with the aero side, but with the mechanical side. You can imagine its bit complicated to keep something still while everything around it is moving. We had problems with it before we could take it to the race. So we had a revised design at Barcelona last week.
From the aero side their pretty complex bit of kit, were still earning them to be honest.
The dimple at the top was there just for legality. That’s why Ferraris looks like someone’s done a messy job of trimming it, its because of legality. Its controlled by the plus minus 160 height overall on the brake ducts. The other thing is that you don’t want the disc touching wheel because when carbon rubs on magnesium it will cut through it like butter, within a lap you wont have a wheel left. So you’ve got to be a bit careful you don’t push for a bit extra and end up losing your wheel.
Of course they contribute to brake cooling, they’re brake ducts…."