2007 Belgian GP Technical Review

Formula One finally returned to one of the best tracks in the world for Round 14 in Belgium.

The Spa Francorchamps circuit is rightly agreed to be the best driver circuit on the calendar. Only its finances and facilities let it down. Now the track has returned with new pit complexes and minor revisions to the track to allow for new runs-off and an altered Bus Stop chicane.

Unlike many tracks, Spa is built amongst the hills and natural geography of the area. Thus, the track is long and varies in height, the emphasis being on long open corners and straights. Only the chicane and hairpin punctuate the fast, flowing nature of the track.

This creates the famous corner Eau Rouge, which dives down from the La Source hairpin before changing direction at its slowest point.

The cars then power back up and over the hill towards Les Combes. This single corner sequence creates an enormous load on the car. In fact, many aspects of the cars designs are built around this corner.

Also, this blast from the first corner leaves the car flat-out on open throttles for twenty seconds, one of two such long runs around the lap. As a result, the track is one of the most demanding on engines, and coming after Monza, the teams with engines that were up to their second race were sensitive towards how many revs they would run through the weekend.

To cope with the track's unusual demands, the cars need to be aerodynamically efficient. But surprisingly, the teams run quite low levels of downforce, comparable to Indianapolis. This is due to the importance of the long straights and the high average speed through the turns.

The cars are less dependent on mechanical grip at Spa, although the ride height and suspension do need to cope with the loadings through Eau Rouge. When their ride height is all used up, there's the tell-tale plumes of yellow dust kicked up as the car bottoms out and the plank drags along the road.

McLaren

As is typical for McLaren, the car's development is very subtle through the season.

Almost unnoticed in Italy but revealed in Belgium was the team's revised diffuser. McLaren have created a slot around the upper half of the central tunnel. This bleeds high-pressure air from outside the diffuser (arrowed) through the slot to prevent the air inside the tunnel from separating from the diffuser roof.

No other team have run a slotted diffuser in this form since the since the early nineties. McLaren must be running an extremely aggressive diffuser to require such a slot.

Ferrari

Coming off the back of a defeat at Monza, Ferrari were expected to do better at the fast, aerodynamically-challenging turns of Spa.

Regardless, Ferrari pressed on with developments for the race, including further revisions to the bargeboard flip-up. This flip has returned, having been replaced by a simple slot on the trailing edge of the bargeboard for most of the mid season.

The new flip-up features slight curl to its forward edge to form a small endplate. Additionally, Ferrari added endplates to the dummy camera pods. Most teams keep their camera pods simple, but do place them carefully to ensure they are aero-neutral, if not providing a small aero benefit.

The nose mounting location places the camera in an area that still allows additional bodywork, whereas the roll-hoop camera mounting is outside the allowable area for bodywork.

Ferrari chose not to run the developments tested in the test at Spa earlier this year, where the T-wings and pod wings received slots to reduce drag.

Minor revisions to the Ferrari included endplates on the camera pods and a new flip up on the bargeboards (yellow) © Scarborough (Click to enlarge)

More reports on Ferrari's damper problem from Monza and some subsequent issues in qualifying for Raikkonen have emerged.

It seems the hypothesis of a roll damper put forward in the Monza technical analysis may be less likely than Ferrari developing their use of the third damper.

Ferrari confirmed to autosport.com that the failure for Massa in Italy was indeed the third damper. Additionally, the evidence presented at the McLaren/Ferrari spy case suggests Ferrari have some novelties in this area.

Again, the Italian media have suggested various theories, both recently and over the past year. Once persistent pair of rumours has been the use of electronic dampers and a method to lower the rear of the car at speed. Both potentially provide active ride akin to that banned for 1994.

Clearly, any true active technology is out side of the regulations. But the rules are typically vague when it comes to damping. Most of the suspension rules in section 10 of the FIA technical regulations relate to suspension geometry.

Damping is not a mechanism related to the suspensions geometry. Thus, Ferrari could argue that a degree of interpretation could be applied to the rule book. It is possible that Ferrari are using the third damper to alter ride height at speed.

Usually, the teams adopt a central element to the rear suspension to alter the suspensions compliance when the car pitches or heaves (that is, both wheels to go up or down together).

Springs, dampers or bump rubbers are used to control both the rate and amount of pitch. At tracks like Monza, the downforce at high speed will compress the suspension and eat up all of its travel. This can lead to the underbody stalling, robbing the car of downforce. The third element prevents this by limiting how much the suspension can drop.

Recent failures and evidence at the spy case point towards Ferrari's third damper (arrowed) © XPB/LAT (Click to enlarge)

But allowing the rear suspension to sink when on the straights is beneficial, as the lower rear ride height backs off the rear wing angle, reducing drag.

In the days of active suspension, this was one of the first strategies teams would adopt to improve the car's performance. It is possible that Ferrari have exploited the rules to allow this happen without the need for active technologies by altering the third dampers rebound setting.

Dampers work in two directions - compression, when the damper is squeezed, and rebound, where the damper springs back to its original length. Each of these settings is adjustable separately, and a damper will compress at a different rate to that in which it extends.

It is possible to set the rebound damping so high that the damper never fully extends back its to original length. In the case of a third damper, this will have the effect of ratcheting the damper to a shorter length as it goes over small bumps. This prevents the rear ride height from recovering to its usual position. Thus, the car can be made to automatically lower itself.

This was a trick adopted in NASCAR, where ride heights and aerodynamics are tightly controlled. Nowadays, the dampers are also strictly controlled to prevent this practice.

If Ferrari has the okay from the FIA to run dampers with a speed-sensitive damping setting, then the dampers could reset to a different rebound setting at a specified speed to compress the damper.

Then, as the car brakes and speed is diminished, the damper returns to the normal low-speed setting, raising the ride height.

Of course, should the system fail for any reason, the impact will be to restrict top speed if the damper is in its low-speed setting. Or, if the damper locks in its high-speed setting, the rear end will be set too low and make the car's handling unpredictable.

Details on the Toyota wing endplate include a chamfered footplate (arrowed) and tyre temperature sensor (yellow) © Scarborough (Click to enlarge)

It could be both Massa's Monza retirement and Raikkonen's Monza practice crash could be caused by the damper failing in its high-speed setting. Ferrari are unlikely to confirm the system is in use, and with few external clues the system may remain secret for some time.

Toyota

In search of efficiency, Toyota retained the cut-back aerodynamics from Monza. The car run without T-wings, but returned to the new drooped nose and bi-plane front wing.

One detail noticed on the front wing endplate is the chamfered footplate, where the usual parallel shape has a section removed from the rear edge. The small pod on the upper section of the endplate is a small infrared sensor to detecting tyre temperatures. These are only fitted during free practice to provide the engineers with data to base their set up and tyre selection on.

Honda

The promise shown by the revised front and rear suspension run by Honda in Monza proved to be a disappointment at the more aerodynamically-demanding Spa track.

Allied to revised suspension, Honda had a new gurney arrangement on the diffuser (Yellow) © Scarborough (Click to enlarge)

Continuing their raft of detail improvements was a new diffuser set-up. The side tunnels retain the same shape as the early season update but now have a different gurney layout, with larger tabs added to the outer edges and smaller wider flaps added to the inner edge. These changes have been made to work in conjunction with the new beam wing first run in Monza.

Spyker

Despite the delay in getting the B spec car to a race weekend, the Belgium track rewarded the changes and the team had a much more competitive showing.

One unique feature on the F8-VIIB is the front wing endplate - an unusual curl has been added to the upper edge. The function of the device is not apparent; it could to be deflect the flow dragged down by the tyre from upsetting the flow passing along the endplate.

Spyker have also added a tube-shaped bulge to their nose fins, which contains their rear-facing on-board camera.