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  Death to the CDG Wing (the future of overtaking in F1)

It seems that the teams who all paid lip-service to the FIA's CDG wing concept when it was unveiled last year have finally told the FIA what to do with it. To its credit, the FIA has listened and agreed to postpone introduction of aerodynamic changes, due to come into force in 2008, until it has examined alternative proposals that the teams have apparently been working on.

I've blogged before about the insanity of the CDG wing. To me it's always looked like the tail wagging the dog in that the problem with overtaking in modern F1 is not caused by the wake of the leading car, but the sensitivity of the following car to that same wake. That sensitivity comes from two factors: One is that in terms of overall downforce, too much now comes from the wings, winglets, flipups and other surfaces on the top of the car as a result of the FIA's year on year restrictions on diffuser size and wing element counts. Secondly, there is specifically a big problem with cars understeering dispropotionately when they get close to another car in a bend. There has always been understeer induced by the wake of a car ahead, but since the front wing has been raised mostly out of ground-effect, it has become almost impossible to pass in the bends.

The CDG wing attempted to improve overtaking by splitting the rear wing in two laterally. The centre of the car would have only neutral or downwards sloping bodywork which would in itself generate lift - not a good thing in a racing car that's supposed to travel at 200mph! It would however be augmented by two wings, one behind each of the rear wheels. These would generate some downforce (although how much would be achieveable in the wake of the wheels is questionable) and the vortices of the inner ends of the two wings would combine to generate a downwash in the centre of the car. The idea is apparently that a following car can get in that central downwash zone and improve it's downforce.

There are questions about whether these two wings could generate enough downforce to keep the car on the road, along with the design looking to be mechanically unworkable (the downwards load from each wing would have to be fed through just one endplate - how thick would that need to be to sustain the consequent bending force?). Setting those concerns aside, it seems to me the whole concept is flawed. It's one thing getting extra downforce from the car in front (or at least avoiding the loss of downforce it would normally get), but the following car only needs extra downforce in the turns. The following car would have to try and stay in this relatively narrow "downwash zone" or understeer out of the corner uncontrollably. I don't think that is an acceptable situation. From a safety point of view the current situation is preferable because at least drivers know they can't get too close and because the downforce falloff is progressive, they never get too close. I don't want to think too much about cars trying to slingshot eachother around Turn 8 at Istanbul and then getting too far out of the downwash-zone and flying off at high speed.

The other way in which the CDG wing concept 'wags the dog' is that it's a radical new (and frankly very ugly) design for a single-seater racecar. It completely ignores that you can have single-seater reacecars that achieve similar levels of downforce to Formula 1 and yet can follow eachother in turns quite well. The evidence is that not only did Formula 1 once have far more overtaking than it does now with similar downforce levels and power, but also that the current GP2 category represents a single-seater with 80% of Formula 1 performance in which drivers can tailgate each other around the whole lap. There is nothing revolutionary about a GP2 car - in many ways it is like a early-to-mid '90s Formula 1 car. The front wing is in ground effect, the diffuser does more of the work and there are few addons like flip-ups, winglets, etc. that are so very sensitive to wake turbulence. The GP2 car designers, Dallara even gave the car small fixed skirts on the edges of the floor in order to add more underbody downforce - the kind of downforce that is less sensitive to the wake of a leading car.

I have observed and commented on all these things before, both on this blog and various web fora. So it was with great pleasure I read today that the CDG wing had been shelved and that the teams themselves have proposed a set of regs that would make Formula 1 more how I see it working. According to an article on gp2006.com, there are two proposals, one of which the FIA in considering. That is for a 2 metre wide car (width was cut to 1.8m for the 1998 season) with a 1.9m wide, low hanging, front-wing and a 0.75m wide rear wing. The diffuser would be much longer, but would be worked less hard to produce less turbulence. All the flipups, winglets and bargeboards would go to cut overall downforce (for safety) and also reduce wake-sensitivity (to improve overtaking).

I'm not sure how a 2 metre wide car with a 75cm wide rear wing would look. I'd rather keep the rear wing in proportion to the size it is now, but limit it to a single element in order to reduce downforce. Several teams ran single-element rear wings in the Monza 2006 race and clearly it works when less downforce (or drag) is the objective.

An important part of the proposal is a widening of the car back to 2m, presumably with some rules on minimum frontal area, to increase drag. And important part of overtaking on the straights is the 'tow' gained from the leading car which reduces your own drag (thus increasing your speed relatively) and downforce. That tow is in proportion to the drag generated by the car in front. If cars are to run less and less wing (as they have done over the past 10 years), then it is important to get some of that drag back and widening the car seems the easiest way to do that without either adding downforce by adding wing elements, or by adding drag artificially (like the Handford device once used by CART on super-speedways).

Anyway, this post is far too long already. I'll just finish it off by saying that I hope something comes of this latest news. It's tempting to picture the FIA as the bad actor in all of this since it's the FIA's rule changes, in my opinion, that have led to the current overtaking-free Formula 1 we have today. However, in most cases those rule changes where proposed by committees made up of team personel. Now the teams want to put things right, the FIA is listening, but many a good proposal has died in the Technical Working Group before. I hope this one wins out and that for 2008 we have some cars the drivers can really race each other in, instead of having to use pit strategy to get ahead.

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one comment:

sir please send the reports and step by step procedure regarding the aerodynamic analysis of rear split wings.bcoz we are doing project on this….........................
mallikarjuna k () - 06 03 07 - 20:24

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