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  Finally, a resolution to the flexi-wings controversy

The "Flexi-wing" controversy has been rattling on since the start of the season. It came to head after round two - the Malaysian Grand Prix - when in-car video clearly showed the Ferrari rear wing flapping about like it was about to fall apart at top speed. The allegation was that flap was designed to flex and that at high speeds it would flex enough to close up the slot-gap between it and the wing's mainplane. That would cause the airflow on the underside of the wing to become highly turbulent. Contrary to some reports, it does still generate a considerable amount of drag (equivalent to, say, dragging a box with the same frontal area along), but crucially it generates significantly less drag than in normal operation.

It was that turbulence generated below and behind the wing that caused the end-plates to wobble like a flag in the wind on the straights in Malaysia. After complaints from other teams the FIA reportedly asked Ferrari to "make changes" to their front and rear wings. They also found issues with other team's wings, including those of McLaren. When round three - the Australian Grand Prix - arrived, it was clear that Ferrari had made changes. Viewed from the same rear-facing camera on the roll-hoop you could see that the end-plates were no longer shaking like mad on the straights. Yet Honda and others still complained that Ferrari were allowing the wing to flex (presumably they'd just stiffened up the rest of the wing-box) and speed-trap results backed this up. The FIA had seemly asked Ferrari to look less like they were cheating without actually banning what they were doing. They did though ask the Technical Working Group (TWG) to come up with proposals for how this slot-gap closing technique could be outlawed in the 2007 regulations.

I should note that it's very difficult to determine the size of the slot-gap from the video footage at any given time because (a) both wing elements are painted white, (b) on the Ferrari, they overlap in such a way as you can't see daylight though the gap even when it is at its fullest, and (c) there's a lot of margin for optical illusion in that kind of analysis because the shadow cast by the flap on the mainplane moves as the car changes direction.

Currently the technical regulations only address flexing wing flaps by applying a weight via a clamp and pully system that pulls the trailing edge of the flap backwards and downwards slightly. That is only adequate to test for the most obvious way to gain an advantage from flexible wings - allowing the flap to change it's angle-of-attack under load (something that the Renault front wing clearly does by the way). There is a limit to how many modes of flexation can reasonably be tested for during scrutineering both due to time constraints and the safety implications of applying large loads to bodywork parts that could fail spectacularly in the scrutineering bay. There is additionally a philosopical point of whether the scrutineers should use video evidence gathered on track or whether they should rely solely on measurements made on the "bridge of doom" in the scrutineering bay.

Regardless of the difficulty of proving wrongdoing in the rear wing of the Ferrari 248, it should be clear to all but the most ardent Tifosi that the flap was designed to deflect at speed. Conventional wings include a rigid support brackets at regular intervals between the mainplane and flap. Most Formula 1 rear wings use either one central bracket or two placed symetrically across the span of the wing. The Ferarri 248 wing features no such bracketry. They have made the flap stiff enough to pass the aforementioned deflection test without support from the mainplane while at the same time being able to flex in a different axis. It's really quite ingenious, but clearly against the spirit of the rules.

This is a point I want to get across as clearly as possible: There are a lot of people who don't think that Ferrari did anything wrong. Although the rules state that bodywork must be rigid, it's an unavoidable fact that all materials deflect under load to some degree. Although the rules don't take account of this (except for the two prescribed rear wing tests which have an allowable margin of deflection), the practice of the scrutineers does. Regardless, there is a fundamental difference between something that deflects out of practical necessity and something that is clearly designed to deflect in a way that affords an advantage. Every other wing includes brackets to support the flap mid-span because if you want the wing to work like wings are supposed to work, you need to maintain the slot-gap under load. When someone designs a wing without those brackets we have to assume that they've either discovered a new super-stiff material to make the flap from, or that they want the flap to deflect in some way.

While the FIA dithered over how best to deal with flexi-wings, other teams have either implemented their own version of the concept so as not to be at a disadvantage (BMW supposedly used such a wing at Silverstone) or at least complained vociferously about being at a disadvantage because the FIA won't issue a clear ruling on the matter either allowing them to go ahead without fear of a ban or banning the concept altogether to put them on a level playing field once more.

The TWG 'ummed and ahhed' and this week came up with the simplest possible solution to the problem: There rules will mandate one or more rigid brackets/spacers between the mainplane and flap that must keep the two elements at least 50mm apart at all times. The rule is worded such that no part of the wing may be more than 250mm away from a support bracket, this wings that currently use one or two brackets are OK with the rule. The beauty of this rule is there's no additional burden on the scrutineers other than checking that said bracket is present and correct.

The FIA then promptly changed their mind and declared that the rule will be applied with immediate effect instead of letting this whole thing rumble on until next season. It means that teams which decided to pursue the same concept as Ferrari have wasted their efforts. Some also feel that this decision favours Ferrari because it means they've had the benefit of flexi-wings since the start of the season while other teams have only just got it working. I can see that Ferrari have benefitted most from what's happened, but I still think it's the right thing to ban flexi-wings now that there is a simple way to enforce the rule. Also, it could be argued that this mid-season rule penalises Ferrari most because their overall package was designed with this wing in mind, and considering they were only barely level with Renault in performance terms already, it could put them out of title contention altogether.

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