27
Mar
10

Unintended consequences: aero development edition

Formula One’s governing body, the FIA, imposed sweeping rules changes upon the teams to begin the 2009 season.  These changes drastically restricted the permitted shapes of the cars’ front wings, sidepods, engine covers, and underbodies in an effort to improve the show (a combination of delicate aerodynamic sensitivity and enormous turbulent wakes from cars in front severely reduced available downforce for cars running close behind their competitors, making passing more difficult) and reduce costs (the theory being that by standardizing or regulating component shapes, teams would have less incentive to run expensive wind-tunnel and CFD aero development programmes on every damn part of the car).

Things, er, didn’t quite work out as planned.

Perhaps the first sign that the teams were finding new and creative ways to claw back the downforce they were supposed to lose under the new regs was the Ferrari F2009 — in particular, its clever outboard mirror mounts, whose support pylons neatly duplicated the vertical elements first introduced by BMW-Sauber at the 2008 Australian GP and widely copied since.  The most spectacular example of rules-bending was the infamous double-deck diffuser configuration developed by Williams, Toyota, and especially BrawnGP (and, of course, widely copied since).  By exploiting a loophole in the underfloor dimensional regulations, teams could use the rear crash structure as a secondary diffuser channel, increasing diffuser volume and thus downforce.

Giorgio Piola complains in his Formula 1 Technical Analysis: 2008-2009 that

[U]nfortunately the text of the regulations left so many grey areas and that they were ‘exploited’ by the various designers to create cars that were equally as sophisticated as their predecessors.

Perhaps even more instructively, he also notes that

[The FIA] also wanted to stop wind tunnel research, even if that kind of development had never been used more intensively than in preparation for the 2009 season, so much so that no fewer than three teams, Ferrari, McLaren, and Renault, went to America to test in the scale 1/1 wind tunnel belonging to Windshear in Charlotte, North Carolina.

(Emphasis added.)

The problem with the FIA’s restrictive mentality is its assumption that teams willing to seek a competitive advantage under a given set of regulations will be unwilling to seek that competitive advantage elsewhere when the regulations change.  Get rid of the intensive aero development on sidepod furniture and front wing centre sections, they figured, and less of that costly aero development will happen.  It turns out, of course, that aero development just shifted to other parts of the car — and since the new cars were starting largely from scratch, their development was revolutionary rather than incremental and required even more money.

Tomba at f1technical gets it exactly right:

One of the aims of last year’s aerodynamic regulation changes was to reduce the interest in aerodynamic developing by limiting the possible development areas, including the front wing. The problem with F1 designers and their teams is that they live for every single tenth, and hence rather then stepping back, a regulation change empowers them to look for other solutions.

(Emphasis added.)

Some of those other solutions can get quite complex indeed.  For example, McLaren’s active rear wing airflow (called an “F-duct” now, ostensibly because of its shape but more likely due to the language it engendered from the rest of the paddock) is apparently controlled by the driver’s left knee:

Scarbs editorializes:

This set up is legal as the rear wing slot in itself is legal (used by McLaren, BMW Sauber last year).  There is no specific working to prevent wing stalling in the rules.  There are no moving aerodynamic parts, except perhaps for the drivers foot\leg.   It’s a piece of interpretive genius, but perhaps as far removed from the spirit of the rules as you can get.

Perhaps the aero section of the technical regulations could be informed by one part of the regs that unequivocally works: the driver safety requirements.  F1’s driver-safety regs are behaviour-driven, not just dimensional.  Monocoques must be crash-tested under a number of impacts and physically demonstrate that they meet certain guidelines — see Articles 16 to 18 of the 2010 FIA Technical Regulations for details — rather than simply appear to meet construction regulations under inspection.  The safety regs don’t say “this is what your crash structure must look like” so much as they say “this is what your crash structure must be able to withstand”.

The aero regs should move in the same direction.  Rather than mandate a fixed centre section for the front wing to “minimize disruption due to turbulence”, mandate instead that the variation in aero load (at a fixed speed) between clean-air and turbulent running be within a certain range.  Rather than try to design perfect diffuser regulations, place limits on the amount of turbulent wake that the whole car can generate.

This principle might also find applications in fields other than professional motorsport.


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