European GP technical review

The European Grand Prix at Valencia has not previously produced much exciting racing, but this year's event will definitely be one to remember - both in terms of action and technical development.

On-track there was Mark Webber's lucky escape from a big airborne accident, plus the controversy over the subsequent safety car, while in the garages themselves teams had been working extra hard to bring a big raft of updates to the event.

Exhaust blown-diffusers

A lot of teams put a great deal of effort into developing the F-duct system pioneered by McLaren, earlier in the season. Now, though, the latest must-have item that outfits are chasing is the Red Bull Racing-inspired exhaust-blown diffuser.

And just as a number of teams were left a bit underwhelmed by the benefits that all their work on the F-duct produced, we did not really see that much of a difference in the teams that moved to the low exhaust configuration in Valencia - Ferrari, Renault and Mercedes-Benz. But it is still early days, and perhaps we will see a bigger leap in performance at the higher-speed Silverstone circuit.

The relocation of the exhaust pipes at the floor of the car, as opposed to on top of the sidepods, brings two notable benefits - firstly, it tidies up the airflow to the rear wing, and secondly it improves airflow to the diffuser.

When exhausts come out of the top of the sidepods, the gases that they expel can affect the rear wing - especially the lower beam wing. Components like the rear wing work best in a neat, tidy and consistent airflow. To get the maximum out of the rear wing the last thing you want is an exhaust pipe throwing hot turbulent air at it on occasions around the lap.

That's not good for consistency.

Mercedes' low-exhaust layout © autosport.com

By moving the exhausts down to the outer section of the underfloor, you get rid of any of the bad flow that affects the rear wing. It also means you are able to put the exhaust gases and air flow on to the upper surface of the diffuser, increasing the airspeed in this area when the driver is on the throttle.

This outer section of the underfloor has a vertical wall that turns outward very abruptly to attempt to get the low pressure area behind the tyre help scavenge the airflow from underneath the diffuser. By exiting the exhaust gasses into this area it also helps fill up the void behind the rear tyres - which is a low pressure zone and creates drag. This will then pull more air through the diffuser, which in turn creates more downforce.

On an F1 car, the four wheels together contribute about 40 per cent of the drag of the car, so anything you can do to help the airflow around them will reduce the drag and help you go quicker in a straight-line.

It is not all win-win though with exhaust-blown diffusers. Temperature management of the design is horrendous - and it was little surprise that Mercedes GP had to make some modifications to its system over the Valencia weekend because things were overheating.

The effort that is now going on in these exhaust areas is just one example of how fine the detail is these days. It is pretty tough understanding all the heat and managing it - so everyone has got to undertake a massive, massive task.

Floor inlets

Ferrari's double-inlet © autosport.com

One of the places that teams have been experimented with a lot has been in the area in front of the rear wheels - where a lot of inlet holes are appearing and being tweaked.

As the rear tyre rotates onto the ground it displaces a lot of air around the contact patch. The complex way that the airflow behaves in this area above and below the underfloor has seen teams experiment a lot with moving it around between the top and bottom surfaces.

On the shot of the Ferrari, you can see that the team has introduced two large inlets into the floor, whereas Red Bull Racing made its single opening much larger in Valencia.

By creating an inlet in this area, and getting the airflow that goes through this duct to influence the airflow that is displaced by the rear tyre, the tyre-displaced airflow will have a less detrimental affect on the diffuser. Managing this is not easy and we can see evidence of this on the Ferrari, where it has fitted a small gurney flap on the inside edge to try and get the air to meet up at the rear of the tyre - where there is a low pressure area.

The idea is to use this low pressure behind the tyre to act as a bit of an extractor and suck through as much air as possible. If you can get the air to get sucked around the tyre, then the air speeds up. This in turn will help the performancce of the diffuser and you will get more downforce and reduced drag.

This little tweak can work very well alongside the exhaust-blown diffuser - but it all requires very careful management of the airflow around the rotating tyre.

Red Bull Racing's new diffuser

Red Bull diffuser © autosport.com

While Red Bull Racing's rivals were copying the idea of its exhaust-blown diffuser, the team itself introduced a heavily updated diffuser in a bid to maintain the speed advantage it has enjoyed all season.

In the photo you can clearly see the exit areas of the lower and double diffuser. On the lower diffuser, the inner splitters are allowed to be down to the reference plane (lowest point of the car) whilst the outer curved wall can only be as low as the stepped plane, which is 50mm higher.

Red Bull's new diffuser features a lot of curves on all the splitter elements. As I wrote after Montreal, McLaren had more rounded edges inside its diffuser, and this is all aimed at helping control air rotation on any vortex that is set-up inside the tunnels.

With square edges, the air on the upper wall and side wall can often travel at different speeds - and that is not very good for consistent airflow through the diffuser. The rounded edges make the speed of the air flowing much more balanced, and easier to control.

Such tweaks will not produce an automatic downforce benefit, as the differences will be quite subtle. In fact, at a fixed ride height, I think there will be virtually no difference between the square sided version and the rounded edge version.

However, on occasoins of varying ride heights - such as under braking when the rear of the car will raise up - then with the rounded edges the diffuser will reattach itself much better. It just makes it much more robust to airflow changes that varying ride height instigates.

Red Bull Racing's wheel hub/brake test

If you wanted some evidence of the kind of attention to detail that Red Bull Racing is putting into all elements of its car, then you need look no further than this picture of it conducting a tolerance test for the brake housing clearance of the inner surface of the wheel rim.

Although brake housings look very complicated, their aim is quite simple. You want to take airflow into the brake cooling duct, pass it through the disc and then try and get the air to flow out on the outside of the wheel. If the air arrives on the inside then you get hot, turbulent flow into important areas of the car -
and you really don't want it in such a downforce-producing flow. The old 'Frisbee' wheel hubs were all about this - but they have now gone.

Without the 'Frisbees' teams have been working hard on trying to optimise the flow - which means carefully managing the gap between the brakes and the wheel-rim. Teams could go down the conservative route and give themselves 5mm of clearance between the two to guarantee there are no problems - but if you are pushing the envelope, as Red Bull Racing does, then you just want enough clearance to allow for rim deflection under cornering loads - something in the region of just 1-2mm.

Using this rim with machined windows gives the team a chance to check on the clearances, and that everything is okay. It is important to make sure that it all fits correctly and the wheel doesn't touch it as a piece of very thin magnesium rubbing on a piece of carbon could lead to a disaster. Checking components like this will be done on every single area of the car.

Renault's duct

Renault's new front brake duct © autosport.com

We have talked several times this year about the rate of Renault's development, and again in Valencia the team continued to push hard. As well as the exhaust-blown diffuser we have already talked about, the team had another new front wing and some tweaked brake ducts.

The shot here of the front of the Renault shows you clearly that the team uses a steering-rack mounted in line with the lower wishbone - just as Brawn GP did last year. It's a nice neat installation and, compared to other cars that have the trackrod as a separate link - I think this is a much better integration and will also help control the airflow wake coming off the front wing much better.

You can also see Renault has implemented some aerodynamic elements to its brake duct too. You can see the hole that feeds the duct - but the rest of it all look like aerodynamic devices to me.

These turning vanes are there to manage the airflow inside the wheels - and because these all turn with the wheel assembly, it means the airflow around this area will be much more consistent with varying steering lock. This leads to less of a compromise in aerodynamic specification and less difference in car balance from low to high speed meaning that the driver is less likely to make a mistake.

Renault's latest front wing © Other

We saw other teams running these vanes, and mini wings in Canada and teams are going to greater and greater extremes to find areas of the car that they can exploit. My estimate is that something as small as this will cost £50,000 from development to tooling and implementation - with each tweak after that costing in the region of £10,000. In the days of big cost cuts in the sport, is that right?