General Talk: Aerodynamics and F1

There is no need to explain how important aerodynamics is to F1 cars. This is the word that we hear everyday but may not have a clear clue of what it is. As there is quite limited space for the development on engine, tyre and other mechanical components, aerodynamics is the single most important performance factor for F1 cars nowadays.

Aerodynamic Impact on F1 Cars

We may take it for granted, but think of those simple airplane wings that hold hundreds of people in the sky… isn’t aerodynamic force astonishing?

The basic idea of aerodynamics in F1 is to find the best compromise between higher downforce and lower drag. As a surprise to most people, passenger car that we use everyday produces lift force rather than downforce due to the shape of it. However, the bodyweight itself generates enough force to keep it on the ground. Nevertheless, additional downforce is essential for F1 cars as the speed of it requires huge amount of grip to enhance its stability, especially at corners, to allow high cornering speed.

WIth higher speed than common cars, most sports cars need rear spoilers to counteract the lift force generated by car body. Shown here – Bugatti Veyron Super Sport 2011
Huge grip needed for F1 cars to maintain high speed at corners

On the other hand, minimizing drag is the priority to production cars considering its benefit for fuel economy. It is also preferable for F1 cars although not of same stress. The trick here is to find the best downforce and drag combination.

Creating Downforce

While increasing weight is clearly not a clever idea to add up downforce, force exerted by the air becomes the major downforce source. Aerodynamic downforce can be either generated by streamlining the whole car or adding on extra aerodynamic features (wings, spoilers, etc.).

The most famous case for streamlining the car is known as ground effect, which suggests that as the car body approaches the ground, higher downforce is generated. In modern IndyCar race, underbody tunnels are carefully allowed to suck it down to the ground. However, the application of ground effect is almost banned in F1 since early 1980s as the car was capable of reaching dangerously high speed at corners. At present, diffuser design is permitted (although with strict regulations) and crucial for F1 engineers to do take some advantage from the ground.

Lotus79 – Old day F1 champion, making full use of ground effect

Compared to streamlining effects, aerodynamics features are more noticeable on a F1 cars. Aerodynamics consideration must be taken into the design of front wing, nose cone, rear wing, etc. These parts are adjusted in each race to match with the circuit condition. Basically, on circuits with long straights (e.g. Monza, Italy) , lower downforce is needed, minimizing drag becomes more important, whereas on circuits with substantial corners (e.g. Monte Carlo, Monaco), downforce is definitely the priority.

Monte Carlo definitely needs more downforce!

 

Measuring Downforce

Due to the complexity of F1 car shape, it’s almost impossible to calculate downforce generated on each parts directly from fluid mechanics formulas. Computational approach, CFD and experimental approach, wind tunnel testing, are both critical method to measure aerodynamic force.

CFD is the abbreviation of Computational Fluid Dynamics. It is based on numerical method and algorithm while utilising computer to manipulate calculation and simulation. It’s integrated with CAD (Computer Aided Design) so that engineers can test their virtual 3D models in simulated air flow. 

CFD demonstrating pressure and air flow direction through the car body

A wind tunnel is basically a tunnel big enough to hold the testing car model, with a powerful axial fan to produce desired type of air flow. It can nearly simulate all kinds of real circuit conditions by adjusting temperature of air, flow direction and speed, ground inclination, etc. Aerodynamic force is measured by sensitive beam balance attached to the test model, while pressure distribution is obtained by pressure taps mounted along different positions of car body. In addition, flow motion can be observed by injecting smoke into the air. There are various scales of wind tunnels. Although full scale wind tunnel may produce the most accurate measurements, considering the huge cost of it, most teams are using 60% or 70% scale models.

A nice video here of Lotus wind tunnel testing:

 

So these are some general ideas of F1 aerodynamics. Each aspect of it can be dug much deeper in detail, which is what I’m trying to do in the following posts. Enjoy Aero 🙂

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