The Car of Tomorrow: Part 1 - the chassis

No, I'm not talking about that new winged NASCAR spec chassis; I'm talking about the FIA's new working 2011 regulations for Formula 1. The changes are vast and the implications far-reaching, so we'll cover some of the major points and what they might mean to the future of the sport. If you want to read the exact rules, pdf's of the chassis and powertrain regulations can be found here.

Its no secret that the FIA's working group wants to increase overtaking, thereby increase the spectacle of the racing. However, there's a fundamental problem here. The FIA wants to ensure that F1 cars are the fastest around a road course; faster than any other racing series. To do this, the cars have to make downforce. But as we've talked about before, inherent in making downforce is leaving turbulent air behind the car, which greatly reduces the effectiveness of the wings on a car following in this wake.



The FIA considered several ideas to try to address this issue, including a rather interesting design called the Centerline Downwash Generating (CDG) wing; basically a wing with the middle section cut out. The aim was that clean air would flow through the middle and downwards, given the trailing car's front wing good air to work with. However, Racecar Engineering (a magazine) did simulations that showed the CDG wing only made the situation more complicated and probably worse for the trailing car.

Which brings us to the current proposed solutions: active aero. I've been a proponent of this idea for a long time, so I'm very excited to see what will happen. The basics are this: within a given range specified by the FIA, the teams will be able to electronically adjust the angle of their wings. The cars will also have a turbulence sensor fitted, and when turbulence is detected, the ride height of the car will be lowered. This puts the car closer to the track, increasing the downforce the car is able to generate. A leading car cannot lower its ride height below baseline. With active wings and active ride height, the FIA hopes to increase overtaking.

The rule changes are also taking into account the application of F1 technologies to road cars. One common area that both road and racing cars hope to reduce is drag. Obviously the need to create downforce creates drag, but downforce is not needed during straight-line driving. On a road car, there is no need to create large amounts of downforce, but the designers must prevent lift at high speed to prevent the car from becoming airborne. This is why many Porsche 911's had spoilers that automatically deployed at highway speeds.

Drag is also created by letting air flow into the car, namely for cooling purposes. Typically, a car (both racing and road) is developed with a radiator opening for largely the worst possible cooling case. However, when the car is traveling at speed, this opening doesn't need to be as large since there is more and flowing over the radiator. By reducing the opening, drag is reduced. This is practical on a road car to increase fuel mileage, and will be allowed in F1 for 2011.

There was talk that the front and rear wings would become spec items, however the FIA has decided that the wings are an important element of styling and the FIA does not wish to have a field of identical-looking cars. However, to control development costs the number of elements (essentially separate wings) in the wing will be limited. The floors of the cars will become spec, with a design that is said to lessen the effectiveness of the front wing.

There are also attempts to ban 'aero-plasticity'; basically a fancy word for wings/floors that bend or move at high speeds. Ferrari developed a rear wing with a slot in it, so that at low speeds the slot would be closed, but at high speeds the air would bend the wing, enlarging the slot and allowing more air through, reducing drag (and increasing top speed). There are also claims that McLaren's front wing and Ferrari's floor both flex at speed. Determining if a part flexes or not is quite difficult, as the FIA specifies a bending test, but this test is carried out in the garage and doesn't use nearly the force that high-speed air puts on a part. The FIA hopes that by allowing other aero technologies, teams won't have to resort to these kind of shenanigans.

There's also talk of some very new and very interesting aero technologies being allowed. Aerodynamics is a complicated topic, but one of the common issues is 'flow detachment'. Basically when air hits a surface, the air will flow along the surface until at some point (perhaps the end of the surface) it 'detaches'. This detachment leaves swirling vortices of air that cause drag. To overcome this, several new technologies are being considered.

First is the plasma generator, which works by having an electric strip along the leading edge of the wing which ionizes (charges) the air. A second charged strip is placed farther back on the surface, which then attracts the charged air, preventing flow detachment. Another idea is MEMS; Micro-fabricated Electro-Mechanical Systems. Basically it’s a strip very tiny little vibrators on the leading edge that create turbulence in the 'boundary layer', which is the layer of air very close to the surface. This air essentially 'sticks' to the wing, but doesn't flow off, thereby increasing the effective thickness of the wing. Creating turbulence in this layer reduces its thickness, reducing drag and flow detachment. This can also be accomplished by tiny holes in the surface, which jet air into the boundary layer.

One problem in aerodynamics is that its difficult to scale things; meaning you can't use small models. Clearly it would be vastly easier and less expensive to build a 1:10 scale wind tunnel and use 1:10 scale models to test designs. However, it turns out that anything less than a 1:2 model doesn't relate well to the full-size car. Its also important to model the effect of the moving road. Therefore, teams have had to construct full-size wind tunnels with rolling roads to get good information. Obviously building and running these full-size tunnels is very expensive. One of the new techniques to model aero is CFD (computational fluid dynamics); basically a computer simulation. Only recently have computers become powerful enough to approximate the complex airflow seen by an F1 car. In fact, the Williams team just bought a supercomputer for this very purpose!

So the new rules argue that most of the teams already have the aero testing facilities, so the new aero rules won't cost significantly more to implement. In fact, there should be cost savings because the adjustability will allow for easier tuning of the car in all situations, instead of having to build 400 wings just to find the one that is the perfect fit for that week's circuit.

In the next installment we'll explore the powertrain regulations for 2011.