F1's 2019 aero rules explained

Formula 1 has long been resistant to change, a situation that was brought about by a perverse governance system, variable amounts of disunity between enfranchised bodies - and, most importantly, teams that guarded perceived competitive advantage to an extreme degree.

The past twelve months have brought a sea change in this situation. Firstly the governing body and the commercial rights holder are aligned in the desire to bring entertainment back to racing and the teams are also seeing the merit, both from a financial and a sporting viewpoint, of providing closer and less predictable racing.

Much of the work is longer term but the FIA took the initiative earlier this year to see if some of the research into the 2021 aerodynamic regulations could be cherry-picked to improve the short-term situation.

Often this is a dangerous thing to do, but already the changes being investigated are better researched than any previous iteration of bodywork rules.

The early work on understanding what it is about the aerodynamic characteristics of the current cars that inhibits close following didn't show up any surprises. In essence there are two features of the wake of a car that are detrimental to the performance of a following car.

The first is the turbulence intensity of the wake, and the second, and far more important, is the low energy or total pressure of the wake flow.

Aerodynamic forces are directly proportional to the total pressure that they experience. Total pressure is made up of two components: the static pressure or ambient pressure, which is mainly a function of weather conditions and altitude; and then there is dynamic pressure, which is a function of the velocity of the air impinging on the aerodynamic surface.

As I've written before, the route to performance on an F1 car is to sweep the wake of the front wheels out to the side of the car so that this low-energy flow, the very type of low-energy flow that is detrimental to the following car, is pushed away from your own car. Unfortunately this also leaves a very wide wake of low-energy air for the following car to drive through.

What is required to improve following car performance is to keep the wake narrow and lift it up behind the leading car in a shape resembling a mushroom. Fundamental to keeping it narrow is to limit outwashing, and a strong rear wing is required to lift it up.

Experimental work on the 2021 regulations showed these features to be uncontroversial. So, while a more complete solution was sought for 2021, a few simple fixes were proposed for 2019.

In order not to interrupt the work on the future car, the teams were asked to carry out some basic research on the new proposals and concentrate on the quality of the wake rather than on the absolute performance of the leading car. While there was some variation of results, not a single one was negative, and therefore the revised regulations were put to a vote.

To the surprise of many, this vote was carried and the rules adopted.

The story didn't quite finish there, though, because once the teams studied the rules in detail they found some ambiguities. At one time this might have been enough to derail the whole process, but in the new-found sprit of cooperation these have been ironed out and a comprehensive, if extremely complex, set of rules agreed on.

So what are the fundamentals of the changes? Starting at the front, the front wing has been simplified by removing many of the appendages that sit on top of it, and the number of elements reduced to five.

Abrupt changes of section which could produce vortices to enhance the main Y250 vortex have been outlawed. Under the wing, the vertical strakes have been limited both in number and geometry.

Most importantly at the front, the wing endplate has been redefined as a much more simple device, devoid of the many sections currently seen. The geometry is such that the outwash angle is limited to 15 degrees and the footplate is less complex. Finally the practice of blowing air through the wheel hubs has been outlawed and the front brake duct outer surfaces simplified.

These changes have de-powered the front wing, and to get balance back the wing is larger with the front moved forward 25mm, the width increased by 100mm, and the height also increased by 25mm.

The bargeboards are also changed by reducing their height by 125mm, although this pre-dates the latest changes and was done to expose more of the chassis to exploit advertising potential.

To regain some performance the plan area that can be occupied by the bargeboards is increased.

At the rear, the wing has been made larger by extending it 20mm rearwards and making it 50mm wider. The depth of the wing is 20mm greater and the DRS now allows a gap of 85mm between wing elements when deployed, 20mm more than before.

The rear wing endplates have also been simplified, again aimed at advertising space rather than wake management.

There are some other detail changes, most of which are a consequence of the main changes, although some detail around the halo junction to the chassis has also been altered to make for better aesthetics.

The big question is whether these changes will make a substantive difference, and I believe the answer is yes.

They will not achieve all that is required for close racing, and indeed even the 2021 aero regulations won't achieve this in isolation, but I do believe that the changes for 2019 are for the better.

There is an immediate cost to the teams in terms of lack of carry-over parts into 2019 but change will always cost money.

The important factor is return on investment, and if we can improve racing and attract new fans and sponsors, then the investment into the many changes taking place over the next few years will be repaid many times over.