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The front wing of a Formula 1 car is without doubt the most complex aerodynamic device in race car design.
Its main function is to generate downforce and will typically contribute towards 25-40% (depending on car setup) of overall downforce levels.
Since the aerodynamic downforce can exceed five times the weight of the car, the front wing alone has the potential to generate enough downforce equivalent to twice the weight of the car! Therefore, not only must the front wing function as an aerodynamic device, it must also be able to withstand the incredible structural loads. During high speed braking for example, the force equivalent to the weight of the car can be hanging from each of the two small front wing pillars.
The front wing is also responsible for modifying the handling characteristics of the car. By rotating the front flap angle, the level of downforce generated by the front wing can be altered. As a result, the total downforce level can be redistributed between the front and rear tyres, permitting the race engineer to correct for understeer or oversteer. The setup can be modified to suit different circuits, weather conditions, tyre wear and driver preference.
Typically when aerodynamic gains are found elsewhere on the car, a front wing adjustment has to be made in order to redistribute the downforce levels to the desired aero balance.
The other major role that the front wing serves is to manipulate the flow to the rest of the car. A vast array of intricate aerodynamic elements have been precisely arranged to direct the flow around the front wheels and control the wheel wakes downstream. The intention is to maximise the quality of flow to the underfloor and diffuser. The increasing complexity of the front wing is a result of the compromise between front and rear downforce generation. Generate too much front downforce and you compromise the ability for the rear to do the same.
Generate too little front loading and the overall downforce level will be reduced (as rear downforce will have to be lowered to achieve the same aero balance).
In fact, often a race car aerodynamicist will seek to maximise the downforce generated at the rear of the car. This is because the underfloor and diffuser are the most efficient downforce generating devices. A substantial amount of load can be generated here for very little drag. Hence it is more desirable to generate rear downforce via the underfloor and diffuser rather than the rear wing (which itself is one of the main sources of drag). Thus, if downforce can be ‘transferred’ from the rear wing to rear underfloor, then the same level of rear downforce can be achieved but with less drag, thereby increasing the overall efficiency of the car. Thus, the general trend of front wing design is actually to maximise the downforce generated by the underfloor and diffuser.
Another critical factor that has dictated the development of the front wing is the condition in which it operates within. Firstly, the front wing is the only major downforce generating device exposed to the undisturbed air. This means a high amount of energy can be ‘extracted’ by the front wing which manifests itself as downforce as well as drag. In other words, the front wing is aerodynamically very sensitive to small geometric changes and as a result, an unprecedented degree of complexity has arisen.
Secondly, the front wing operates in ‘ground effect’. This is the phenomenon whereby as the proximity between ground and the front wing diminishes, an enhancement in downforce level is observed at an exponential rate (that is until the wing ‘stalls’ – more on this in the next article). Ground effect increases the efficiency of downforce production and is partly why the latest trend is to run the car at extreme rake (i.e low front ride height and high rear ride height means the front wing sits closer to the ground).
Thirdly, because the front wing is mounted forwards of the front wheel axle line, small variations in front ride height can lead to relatively large changes in front wing ground proximity. Hence downforce levels can change dramatically leading to sudden and large shifts in aero balance. Therefore another goal of front wing design is to mitigate the amount of ‘ride height sensitivity’ to produce a car with consistent aero balance as the car navigates its way through the track. Ride height sensitivity mitigation is perhaps the most challenging aspect of the design, as the wing has to be optimised across a large operating range (this makes it computationally very expensive when developing in CFD).
In the next article, we’ll take a deeper look into the underlying physics which drives the design of the front wing. We’ll investigate some of the fundamental aerodynamic mechanisms involved and study how their behaviour can profoundly influence the performance of the car.
The previous articles in the series can be found below.