INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR

DANIEL BAKER | YEAR ONE PROJECT | NORTHBROOK COLLEGE |2012/13COURSE LEADER: MR. DAVID TUCKER

FdEng Motorsport Engineering INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR

[INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1

CAR] DANIEL BAKER 2013

Table of Contents1. Introduction..................................................................................................................................................3

2. Aerodynamics...............................................................................................................................................5

2.1 Bernoulli’s Equation.............................................................................................................................5

2.2 Streamlines..........................................................................................................................................6

2.3 Drag......................................................................................................................................................7

2.3.1 Viscosity...........................................................................................................................................8

2.3.2 Boundary Layer................................................................................................................................8

2.3.3 Skin Friction Drag.............................................................................................................................8

2.3.4 Form Drag........................................................................................................................................9

2.3.5 Induced Drag....................................................................................................................................9

2.4 Lift/Downforce...................................................................................................................................10

2.4.1 Coanda Effect.................................................................................................................................11

2.5 Slipstream/Wake................................................................................................................................11

3. History of Formula One Design...................................................................................................................13

3.1 The Early Days....................................................................................................................................13

3.2 Safety and Chassis Design Revolution................................................................................................13

3.3 Aerodynamics Arrive..........................................................................................................................14

3.4 Pushing Design to the Limit................................................................................................................14

3.5 Turbo Era............................................................................................................................................15

3.6 Modern Day.......................................................................................................................................16

4. The Formula One Car..................................................................................................................................17

4.1 Makeup of an F1 Car..........................................................................................................................17

4.2 Aerodynamic Package........................................................................................................................17

4.2.1 Front/Rear Wings...............................................................................................................................18

4.2.2 Floor and Diffuser..............................................................................................................................20

4.2.3 Other areas........................................................................................................................................22

5. Design Process............................................................................................................................................24

5.1 Initial Design/Conception..........................................................................................................................24

5.2 CAD...........................................................................................................................................................25

5.3 CFD............................................................................................................................................................26

5.4 Wind Tunnel..............................................................................................................................................27

5.5 Simulation.................................................................................................................................................27

5.6 Testing.......................................................................................................................................................28

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5.7 Development.............................................................................................................................................28

6. Design Innovations over the Years..............................................................................................................29

6.1 Chapman Legacy................................................................................................................................29

6.2 Shape Defining Innovations................................................................................................................29

6.3 Short-lived/Banned Innovations........................................................................................................30

6.3.1 Brabham Fan Car...........................................................................................................................30

6.3.2 Ground Effects...............................................................................................................................30

6.3.3 Active Suspension..........................................................................................................................31

6.3.4 Mass Damper.................................................................................................................................31

6.3.5 X-Wings..........................................................................................................................................31

6.4 Recent Innovations............................................................................................................................32

6.4.1 F-Duct............................................................................................................................................32

6.4.2 Blown Diffuser...............................................................................................................................32

6.4.3 Double Diffuser..............................................................................................................................32

7. Conclusion..................................................................................................................................................33

Critique...........................................................................................................................................................36

References...........................................................................................................................................................37

Bibliography........................................................................................................................................................38

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INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR

1. IntroductionFrom the very outset of this project I was tasked with undertaking for the Fd.Eng Motorsport

Engineering I had decided to base my work around the subject which I am most passionate about, Formula 1, and a subject which I am keen to learn more about and improve my skills at in, aerodynamics and the use of tools such as CAD and CFD in the field. Initially the aim of the project was to ‘Research and design a Closed Cockpit and Wheel Cover systems for use in Formula One, with the aim of improving driver safety and overall car performance ’. However after performing the initial research into this area of Formula One design it became apparent that the information readily available surrounding this area of driver safety was primitive at best, meaning it would have been difficult to discuss and design such a solution in great detail. Therefore as opposed to simply focusing my project on one single design area I have decided to further quench my appetite for Formula One by looking into the overall design philosophy of the modern day Formula One car and the ways in which tools such as CAD and CFD are used to move these designs from the mind into reality.

So For my year one project I have decided to undertake an investigation into the aerodynamic design of the modern Formula One race car as well as the process that is followed by many teams up and down the grid in the world of Formula One in order to produce this monumental feat of engineering. For the purposes of this project I have firstly looked into the theory of aerodynamics as a concept, looking into the reasons why it affects the flow of air and how this theory is put to use to produce downforce on a body. Following on from this initial grounding in aerodynamics, the ways in which the design of a Formula One car works to produce downforce was studied. Research was carried out into the overall makeup of the modern day F1 cars aerodynamic package and the many different steps that are involved in design process, allowing me to look into the various design tools and methods that are put to use by the engineers and designers of the F1 world in the pursuit of creating the fastest car possible.

The aerodynamic design of a Formula One car has progressed at a rate so substantial that the cars we saw line up in the early years are unrecognisable from the ones we see today. The massive advancements in technology alongside design innovations year after year have transformed the Formula One car from its initial conception in the 1950’s, when essentially it comprised of simply four wheels with the best engines of the day strapped to the front with little thought given into the driveability of the vehicle, to the precise feats of aerodynamic engineering that make up the Formula One cars that we see today. This radical change in design over the decades has been made possible by the advancements in design methods and tools used in the sport, completely redefining the process in which design engineers follow when creating these pieces of art. The changing face of the Formula One car over the years is the result of vast amounts of progress that has been made in aerodynamic design of the car, with many innovations creating the defining image that we see on the modern F1 car.

As a result of this change I will be briefly discussing the history of the Formula One car, allowing me to research into the theory behind many of these innovations that lead to the change in design over the years and the issues which resulted in the cars looking like they do today. Having researched the basic concept of aerodynamics and how this theory was put to use in the aerodynamic design of a Formula One car past and

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present, I will finish up by having a look into some basic aerodynamic analysis in an effort to put what I have learned over the course of the project into practice, providing a concluding chapter to my research.

From a personal point of view I have always been fascinated by the way in which the most talented Formula One designers are able to envisage ingenious ideas to unlock performance in areas of the car that many thought was not possible, which in many cases involves ‘bending the rules’. For this reason I will be looking into several of the technical innovations that have cropped up over the years in the pursuit of speed, most of which have subsequently been banned, but are none the less fascinating feats of engineering.

Finally having undertaken the research into this world of Formula One design I will hopefully be able to gain a far great understanding of the ways in which designers come up with new ideas and move them from the drawing board onto the race car for real, sometimes in the pursuit of gaining fractions of a second. This greater understanding will stand me in good stead to progress my knowledge of tools such as CAD, and looking further afield, CFD, that sections of this project will be based around and an area that I am keen to work in in future years.

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Figure 2.1 f1-country.com

Downforce



2. AerodynamicsAerodynamics is the single most important factor in the performance of a Formula One car, with the

concept being put to use in the design of the cars to produce the astonishing cornering speeds the modern car is capable of. Aerodynamics itself is the motion of air around an object and the forces that this creates. In this chapter the various theories and phenomena’s upon which aerodynamics is based and the ways that the concept is able to produce forces such as downforce will be discussed.

2.1 Bernoulli’s Equation The fact that the Formula One cars we see today are capable of such high cornering speeds due to aerodynamics is in many ways thanks to the work done by one man, Daniel Bernoulli, way back in the 1700s. The concept of aerodynamics and the laws, upon which it abides by, are as a result of the famous equation that Bernoulli derived during his study of moving fluids and the forces acting upon them all those years ago. A Formula One cars aerodynamic performance is gauged and improved upon by use of the formula, which details the relationship between fluids, of which air is, speed and pressure. There are many different variations of Bernoulli’s formula; the form that is relevant to the downforce that a Formula One car produces is as follows:

Ps+12

ρ V 2=Constant ¿' Total Pressure '

Ps=Static Pressureρ=Air DensityV=Flow Velocity

From this formula we can see that any increase in pressure will result in a decrease in the velocity, as the resulting force is always a constant. Therefore the opposite will also be true; meaning an increase in velocity would lead to a decrease in pressure. It is this law of aerodynamics that explains the ways in which aerofoils, or wings, are able to produce lift or downforce. This incompressible nature of the fluid results in the pressure and velocity differences that produce the downforce from a Formula One wing. As air flows simultaneously over the upper body and beneath the underside of the wing, the velocity of each of the streamlines of air changes. The air flowing under the wing will follow the curvature of the wing to meet with the upper stream at the trailing edge. This turning on the underside, as shown in figure 2.1, will lead to an increase in airspeed, meaning its velocity will increase. The increase in velocity will create a low pressure zone under the wing, with the slower velocity of the streamline on the upper body of the wing creating a higher pressure zone. The air will then be attracted towards this area of higher pressure on the top of the wing, pushing the wing towards the ground and as a result creating downforce.

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Figure 2.2 www.avalanche-center.org



The way in which Bernoulli’s equation is used by an aerofoil to produce downforce can be transferred to the entire design of a Formula One car, with the aim of creating a faster flow of air on the underside of any surfaces, or for that matter the entire car, than that flowing over the top of the same surface. From here we can conclude that the faster air flow on the underside will result in downforce being produced.

2.2 StreamlinesThe concept of aerodynamics revolves around the streamlines of air that pass over an object that is in

motion. This streamlines are the image that most will visualize when thinking of aerodynamics and can be seen with use of smoke injection in a wind tunnel. As air flows over an object, it does so in layers. These layers are known as being either attached or separated from the object and the better the aerodynamic shape of an object, the more attached the layers will be. Keeping the layers attached to the object as they flow over it is vital in reducing the levels of drag created as well as helping to create greater levels of downforce. This is because if the air was to become separated then the layer of air would become turbulent and flow separation would occur. This can have the result of creating eddies and vortices in the air flow that cause an up wash, which would have a detrimental effect on the aerodynamic performance of the car as this would create drag and potentially cause flow separation.

The flow of these layers of air over an object can be described as being either laminar or turbulent. A laminar flow is the ideal situation, with the streamlines flowing parallel to each other in a neat and organised fashion. A Laminar flow is desired over the top surface of a Formula One car as it will invariably occur at a low velocity, meaning that the air flow on the underside will be of the desired higher velocity. A Laminar flow is also far easier to analyse as it will be easier to predict and visualize. A turbulent flow will occur when the layers of air become disturbed and start to flow in different directions. A Turbulent flow can be caused by factors such as the weather, or by the design of the car itself. A turbulent air flow will usually occur in a situation of high velocity, so can often be found on the underside of a Formula One car where the air is accelerated. Figure 2.2 shows the several layers of air flowing over an object, and also indicates differences between laminar and turbulent flow that is created as a result of the objects shape.

Determining whether a streamline is turbulent or laminar is important to the design of a Formula One car as the different forms of flow have dramatically different properties when it comes to the issues of drag and flow separation. Whether a streamline is laminar or turbulent can be determined through its Reynolds Number. A Reynolds Number is the ratio between the viscous forces acting on, and the forces contributing to the velocity, of a flow of air. A low Reynolds Numbers would indicate a streamline where the viscous forces are dominant, with the opposite true for a high Reynolds Number. The Reynolds Number in relation to the air flowing over a Formula One car can be calculated through the following equation:

ℜ= ρVLμ

ρ=Air DensityV=Air VelocityL=Car Lengthμ=Air Viscosity

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If the result of the above equation in relation to a flow was to result in a Reynolds Number of less than 2000, then the flow can be termed as laminar. Therefore if this number is greater than 2000 then the flow would be turbulent.

2.3 DragAny object that is subject to the flow of air will create a certain amount of drag that will work against

the motion of that object. Drag is one of two forces, the other being pressure, that are produced as a result of aerodynamics. The force in question here is the shear force that acts in parallel to the surface of the objects body. The shear force created only works towards creating drag, and has no effect on the downforce produced. As a result the design of any aerodynamic object will be geared towards minimalizing the amount of drag produced. There are several different types of drag, the impact of which can all be determined through use of what is termed the drag equation:

FD=12

ρv2CD A

ρ=Fluid Densityv=Object VelocityCD=DragCoefficientA=Area of Object Cross Section

Any object of any shape possesses a certain drag coefficient, as shown in figure 2.3, with the higher the number the greater the force of drag will be. The drag coefficient of an object can be calculated from the following equation:

C p=2 FD

ρ v2 A

FD=Drag Forceρ=Fluid Densityv=Velocity of objectA=Area of object

Most modern cars, and more specifically race cars, will have a drag coefficient of less than one; with a Formula One car varying between roughly 0.75 and 1.45 depending on its aerodynamic set up. It is important to note that a Formula One car will possess quite a high coefficient of drag as a consequence of firstly the rules that stipulate that they must be of an open wheeled and cockpit design which themselves create drag, and the fact that the design of a Formula One car is centred on producing downforce, which will always result in drag

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Figure 2.3 brighthubengineering.com



being produced as a side effect. Therefore the design of a modern Formula One car is a compromise between downforce and drag. It is for this reason that many objects subjected to motion have a slick and streamlined design, seeing as this shape produces less drag. The tear drop shape can be seen to be ideal, creating little drag as the shape helps to prevent flow separation that would result in drag. An object that possesses a drag coefficient of equal to one will be subjected to stagnation pressure. This is where the velocity of the air flow slows to zero, which, as Bernoulli’s equation tells us, means the static pressure will equal the total pressure. These areas of stagnation pressure will pose as the areas where the maximum pressure is generated on an object, and will be commonly found on the leading edge of a Formula One cars wing where the air flow is equally as likely to divert under or over the wing.

2.3.1 ViscosityAn important factor that causes drag on an object is the viscosity of air. Viscosity is the ‘stickiness’ of a

fluid and, although not immediately obvious, air is a viscous fluid. The greater the viscosity of a fluid the harder it becomes to push an object through it. Therefore it is this viscosity in the air that results in drag being created, as the ‘stickiness’ works to push against the object moving through it. The viscosity of the air flowing over an object results in one of the fundamental concepts of aerodynamics forming, the boundary layer.

2.3.2 Boundary LayerAs discussed earlier, the flow of air passing over an object consist of several thin layers or streamlines

of air that are either laminar or turbulent. One of these layers is known as the boundary layer which plays a significant role in the aerodynamics of an object. The several layers of air flowing over an object do so at differing speeds, with those closer to the object moving slower than those that are further away. Most of the layers move at what is known as free stream flow, where the velocity of the air is at its free stream value. The viscosity of the air causes the layer closest to the object to slow to a velocity of zero, as the particles in the air ‘stick’ to the object. The layers above this one closest to the surface gradually increase in velocity, as the force of the viscosity of the surface air decreases, until the free stream speed is reached. This area of transition from the velocity of zero found at an objects surface to the velocity of the free stream layers is termed the boundary layer, and is represented in figure 2.4.

The Boundary layer plays a critical role in the drag produced by an object, and is therefore crucial in the design of a Formula One car. The thicker the boundary layer, the more viscous it becomes, meaning that the thicker the boundary layer the greater the levels of drag produced will be. Generally the boundary layer will start out as a thin laminar flow at is origin, and gradually get thicker and more turbulent towards the rear of the car as the flow is disturbed This increase in thickness can lead to problems such as flow separation and result in a significant increase in drag coupled with a loss of downforce. However the boundary layer thickness will decrease as the air speed around the object increases, as the momentum of the free stream layers will be greater than the force created by the viscosity at the object surface. Taking all this to hand we can see the importance of minimising the thickness of the boundary layer in the design of a Formula One car in an effort to reduce the levels of drag.

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Figure 2.4 www.grc.nasa.gov



However it must be said that even though there are many benefits to maintaining a prolonged laminar boundary layer in the form of drag reduction, a turbulent boundary layer can also be beneficial to the performance of the car. A turbulent boundary layer can help to reattach any air flow that has become separated, as the velocity of the non-parallel particles in the turbulent flow can help to reenergise the separated flow, helping to attract it back towards the car.

2.3.3 Skin Friction DragThere are three critical forms of drag that Formula One designers must work against in the design of

their cars. The first of these forces is skin friction drag. This is created as a result of the boundary layer that we mentioned previously. As we know the flow of the boundary layer over a Formula One car will start of in a laminar form and gradually change to become turbulent. This change from a laminar flow to turbulent is known as the region of transition, and it is this turbulent area of the boundary layer that causes what is known as skin friction drag. The more turbulent the flow of air, the greater the viscosity of the boundary layer will be. This viscosity causes a friction between the air flowing over the car and the cars surface. This friction that develops creates a resistance to the motion of the car, a resistance that is of the form of drag. In order to reduce the impact of skin friction drag designers will aim to limit the region of transition by making the car as streamlined as possible, allowing for a more prolonged laminar flow, and limiting the length of the car to the only the necessary length, as the further the air flows across a surface the more turbulent it will become.

2.3.4 Form DragThe second type of drag that Formula One designer must contend with is that of form drag. From drag

is the resistance the objects cross section surface area creates as it passes through the air. The drag coefficient of an object is directly related to the form drag that the object produces, with those of a lower drag coefficient being able to ‘slip’ through the air with little resistance. This issue of form drag is the reason as to why the front end of a Formula One car features few vertical flat faces, as these would cause drag. Instead the front end features areas that have very small cross sectional areas.

The impact of form drag will be largely dependent on whether the air flow is laminar or turbulent as it passes over a particular area of the car. The flow of air will always look to stay attached to an object, as is the case with a laminar flow, and the shape of an object will determine whether the air stays attached or if flow separation will occur. Flow separation will result in an increase in drag. As stated earlier the tear drop shape has been found to be the ideal shape for reducing drag, as the rounded front and narrow rear help to keep the air flow firmly attached. This tear drop shape can be found on a Formula One car, starting at in the middle section where the side pods begin, and then gradually moving towards the rear as the cars bodywork becomes narrower, resembling a coke bottle. This shape helps to keep the air flowing around the side of the car attached, reducing drag.

2.3.5 Induced Drag

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Figure 2.5 Showing the reasons we see frictional and form drag people.oregonstate.edu



The third significant form of drag that causes resistance to the motion of a Formula One car is that of induced drag. Induced drag is the resistance that is created from the aerodynamic components of the car that work to produce downforce. For this reason we can see why it is termed ‘induced’ as it is caused by objects placed there by the designers as opposed to being a consequence of the natural shape of the car. Induced drag is an unavoidable side effect of any aerodynamic device on a Formula One car that works to produce downforce. For this reason designers will look to find a balance between the induced drag caused by an aerodynamic feature and the downforce that it creates. The impact of induced drag will be dependent on the levels of attack that a wing is set up to, with the higher the angle the greater the downforce and drag. The higher the angle of the wing the greater the pressure difference between the upper and lower surface will be, meaning more downforce is produced, however this higher angle will also cause more turbulent vortices to be created at the wing tips. These vortices create drag and limit the straight line speed of the car. It is for this reason that we see aerodynamic set up changes from circuit to circuit, as on tracks that feature long straights the wings will be adjusted to run at a flatter angle, meaning less drag is created.

2.4 Lift/DownforceThe main aim of the aerodynamics of a Formula One car is to produce downforce. As we learned from

Bernoulli’s equation, downforce is created from the pressure differences of the flow of air running over and under an object. Downforce is the term given to negative lift, and is achieved through the use of the basic aerofoil shape, run in an inverted fashion as to place the long chord of the foil facing downwards. This orientation of the aerofoil works to force the air running on the underside to accelerate as to maintain the velocity and stay in stream with the air flowing over the top surface. This increase in speed causes the pressure to drop, resulting in the air flow above the aerofoil being attracted to the high pressure zone on the top surface, pushing the aerofoil to the ground; this phenomenon can be seen in figure 2.6

Of course not all aerodynamic devices are of this same shape; however they do all work to the same principle of accelerating the air flow running on the underside. As stated earlier downforce is always a compromise between the force created by the downforce and that caused by drag. As we will discover later in the project, designers over the years have found various ways of producing downforce in the design of a Formula One car. The three main methods of producing downforce are in the use of wings that will be run at certain levels of attack as to accelerate the air faster, the overall shape of the cars body and through the use of a venturi system that will work to accelerate the flow of air running through it. We will look further into these methods later on.

The optimum flow form for downforce to be produced is laminar; therefore many aerodynamics devices are designed to keep the flow of air laminar as to allow other devices to work more efficiently. Flow separation that can be caused by a turbulent flow over the upper surface can lead to a lack of downforce, so designers will look to iron this issue out in the design of their cars.

The amount of downforce produce by an object is again dependent on various factors like air density and velocity. However there are two particular coefficients that have a major bearing on the levels of downforce produced. Firstly the pressure coefficients of the various points on an object will determine its

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Figure 2.6 www.diracdelta.co.uk



effectiveness at producing downforce in the first place, as from this coefficient we can see and map the areas of high and low pressure on an objects surface and throughout the entire flow of air, aiding in the design. The pressure coefficient of an object can be determined from the following equations, which one is used is dependent on the surrounding environment and specifically the speed of the air flow and whether it is compressible or not:

CP=1−( VV ∞ )

2

CP=p−p∞

(12 ) pV ∞2

p=pressure at given pointV=velocity of fluid

This pressure coefficient can be used to identify areas of high pressure on a Formula One car, meaning the design can be analysed as to determine whether an aerodynamic device is working as intended.

The second coefficient that has a bearing on the downforce produced by an object is its coefficient of lift. Similarly to a drag coefficient, the lift coefficient of an object determines how effective its shape is at producing lift. Related to a Formula One car, a negative lift coefficient is desired as to produce negative lift, or downforce. The lift coefficient of an object is required to calculate the total lift force that it is able to produce, however like a drag coefficient this number is usually a known value and acts as a constant in the lift force equation. To calculate the lift coefficient of an object the following equation is used:

CL=L

12

ρV ∞2 A

ρ=Fluid DensityA=Object AreaV=Air Flow VelocityL=Lift Force

Finally to calculate the lift force of an object or in relation to a Formula One car the negative lift force, the following equation is used.

LF=CL12

ρV 2 A

The lift coefficient takes into account the effect of the shape of the object relevant to the formula has on the air properties of the flow stream, with the area the being reference plane upon which the total value of the change in pressure is found. Obviously any result from the above equation that is a negative number will produce downforce as opposed to lift, so we can see how the equation is relevant to Formula One.

2.4.1 Coanda EffectThe Coanda effect is an important phenomenon

within the aerodynamic principles and is the basis of how

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downforce is produced by a Formula One wing. The Coanda effect states that a flow of fluid, like the air flowing over a Formula One car, is likely to become attached to a surface in close proximity, as shown in figure 2.7. It is this principle that allows us to understand why the many layers of air travelling over a Formula One car will remain attached to its surface rather than simply continue in a straight line. The air flow will follow the route of the surface and realign with the free stream flow upon passing the surface. The Coanda effect is especially prevalent on curved surfaces such as an aerofoil, where the flow of air will look to follow the curvature of the surface. This phenomenon has allowed designers to experiment with varying shapes and angles of attack with their wing designs, as the coanda effect will allow for the flow to travel over the upper and bottom surfaces of the wing, creating the pressure difference required for downforce to be produced.

2.5 Slipstream/WakeWe could not finish this chapter on the basics of aerodynamic theory without looking at the reasons

for and effect of an objects wake as it passes through air. The wake that is generated by an object that moves through air also has a bearing on the aerodynamics of that object itself, as the extra energy required to carry this wake in its trail will contribute to the drag of the object. However the wake generated by an object will have a far greater impact on anything following behind. When the object in question is a Formula One car, the wake that is generated is generally referred to by the terms ‘slipstream’ or ‘dirty air’.

The wake that is generated by a Formula One car can be both beneficial and detrimental to the aerodynamic performance of any rival cars following closely behind, roughly up to 10 to 20 car lengths depending on set up. The strength and reach of an objects wake is largely depended on the form drag of the object, with more streamlined and slippery shapes having a far smaller wake, as shown in figure 2.8. This is because the wake of an object consists of the turbulent air that is generated as the air flow becomes separated from an object towards the rear, and then when complete flow separation occurs as it drops of the end of the objects surface. This turbulent flow continues to circulate after the object has moved on, leaving a track of ‘dirty air’ behind the object. Any car that then passes through this turbulent area will suffer from a lack of downforce that will lead to issues such as understeer, as it will not be able to gain the advantages of the laminar flow that it would encounter in an undisturbed flow.

As well as the turbulent flow that follows in the track of an object, aerodynamic devices like wings will create vortices at their tips as the air passes over them, as seen in figure 2.9. These vortices will contribute to

the ‘dirty air’ generated by a Formula One car.

A car following in the wake of another can gain an advantage by using a technique known as slipstreaming, or drafting, in order to gain an increase in straight line speed. The turbulent air left in the trail of a passing Formula One car will continue to travel in the direction of the car, rather than remain static, and therefore will travel at a similar velocity. This will result in a continuous separated flow behind a Formula One car, meaning that the car will effectively be ‘punching’ a hole in the air as it passes through it. This ‘hole’ will be

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Figure 2.8 howthingsfly.si.edu

Figure 2.9 asracingblog.com



moving at the same velocity of the leading car and will therefore create a zone of reduced atmospheric drag behind the leading car, meaning that any car following in this zone will suffer from far less resistance as a result of drag, and will therefore be able to achieve a higher top speed.

3. History of Formula One DesignBefore any discussion into the aerodynamic design of the modern F1 car and the tools which are used

in its design, it would be best to firstly look briefly into the history of the design of the cars that we have seen in the past and how they have evolved from the primitive design of the 1950s, to the precise feats of aerodynamic engineering that we see on today’s F1 cars, that are in essence an upside down aeroplane, with many of the advancements in technology and design taken directly from the aerospace industry itself.

3.1 The Early DaysThe Formula One world championship as we know it today was conceived in the year 1950, with a

variety of the top car manufactures across Europe, along with several independents, competing with the sole aim of winning. With the conception of the Formula One world championship, so with it came the birth of the Formula One car itself. During the early days there was a notable difference in the design theory behind the cars which made up the grid, due to the somewhat lax regulations that were enforced at the time and the substantial differences in budget.

Despite this most of the cars typically followed the same core design philosophy, comprising of front mounted engine, narrow tyres and basic drum brakes. This primitive design was a result of little evolution into the design of single seat race cars being made over the previous fifteen years, due mainly as a consequence of WWII. The lack of evolution is best observed by the fact that the leading car of the first few years, the Alfa Romeo 158, was developed way back in 1938. The 158 offers a good example of the design of these early grand prix cars, as little thought was given to the aerodynamic efficiency of the car, in fact the main cooling system employed by teams at the time consisted simply of a radiator and air intake being place at the nose of the vehicle, causing a serious obstruction to the aerodynamic s of the car. These cars were built purely for speed, with the little aerodynamic knowledge that was factored into the design of the Formula One car being centred on streamlining the bodywork for greater a top speed.

The arrival of Mercedes-Benz to the series brought about a greater level of professionalism to the sport. With their all-conquering W196 which pioneered the use of several new technologies in the sport such as fuel injection and was the first to put greater focus on the ‘streamlining’ of the bodywork. This forced the other competitors to up their game, and most importantly deviate away from the traditional design of grand prix cars that had been used for the past few decades.

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The first significant change in design that led to the cars we see today was the relocation of the engine block from the front to the middle of the vehicle, with the engine mounted behind the driver. This design theory was introduced to the sport by Cooper in 1955, having been initially pioneered by Auto Union way back in the 1930s. This design method proved far more beneficial than its front engine counterpart, becoming the standard before the decade was out. The transition from front-engine to mid-engine brought with it far greater handling characteristics and opened the minds of engineers of the time to pursue design ideas that would lead to greater cornering speeds, as opposed to straight-line.

3.2 Safety and Chassis Design RevolutionThis pursuit of cornering grip swiftly brought an end to the somewhat ancient, and dangerous, use of

drum brakes, which if nothing showed how little thought was given firstly to driver safety and to anything other than straight-line speed in the initial years. The introduction of the mid-engine race cars brought about the use of the disc brakes, still widely used to this day, as a means of stopping the car. It was around this time that driver safety was first contemplated when the cars of the day were being designed. The year 1960 marked the introduction of the first safety regulations being enforced by the governing body. These forced designers to introduce features such as roll-over bars into the design of their race cars, resulting in significant visual changes to the design of the Formula One cars of the day and bringing them more in line with the present day.

The implementation of safety features and the change in braking system itself lead to dramatic improvements being made in car design and lap times over the next couple of years, however it would not have such a significant impact that the next innovation in design would make on future grand prix cars. 1962 brought about the introduction of the monocoque construction that would lead to a revolution in the chassis design of all subsequent Formula One cars up and down the grid. The switch from the traditional tube like frame to the monocoque method allowed engineers to place the drivers in a position far more reminiscent to the situation that we see today where they are basically lying on their backs. This shift in chassis design allowed for far more aggressive designs to be used in the pursuit of lowering lap-times, seeing as the driver was now far less of an obstruction.

The monocoque construction allowed for far stronger chassis being designed. This lead to the introduction of grand prix cars that were visibly ran at far lower ride heights and had a significantly narrower and lighter chassis. This step in Formula One car design opened the road for the introduction of an innovation that led to the cars resembling the ones that we see today.

One of the most significant evolutions in the design of the Formula One car was the introduction of the Ford Cosworth DFV engine. The Ford Cosworth DFV brought about a revolution in Formula One engine design that still stands true today. The DFV engine was initially introduced in the year 1967 and proved to be staggeringly successful in comparison to many of the flat-12 engine configurations that were being employed by teams such as Ferrari at the time, winning over two thirds of the races that it competed in. However rather than the engine itself being a significant evolution in Formula One car design, it was the manner in which it was mounted that did. Colin Chapman introduced the concept of using the engine as a stress bearing unit, or structural member, effectively making it a part of the chassis from which other components such as the rear suspension could be attached. This design theory quickly became the norm and is still widely accepted as the ideal method of attaching the engine to the monocoque.

3.3 Aerodynamics ArriveThe aerodynamic wings that we see on the modern Formula One car have become synonymous with

the sport, and it was towards the end of the 1960s that we saw the initial foray into the use of aerodynamic wings to provide downforce. The lowering of the chassis allowed for greater emphasis to be placed on the aerodynamics of the vehicle as a whole and it was during the 1968 season that the first front and rear wings began to crop up among the field.

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The use of front and rear wings in the sport to produce downforce was instigated by designers taking knowledge from the way in which the aviation industry employed wings into their aircraft design to produce flight, and applying this to the design of the Formula One car, only in the reverse manner to produce downforce. Designers faced initial difficulty in getting the concept to work, with many attaching bizarre looking struts to the front and rear of their cars that were eventually banned due to safety concerns. However by the end of the decade front and rear wings were being employed throughout the grid to great effect, and were fixed directly to the chassis itself.

Over the next few seasons the research into the use of wings and other aerodynamic innovations to produce downforce ballooned, with designers eager to extract maximum potential from this new found gold mine that was aerodynamics. This flurry of activity led to an array of differing concepts, such as the Hesketh front-front wing, being trialled up and down the grid, many of which led to the creation of hideous and downright stupid looking cars being developed by teams.

3.4 Pushing Design to the LimitIt was not the use of wings as an aerodynamic benefit that would have the greatest impact on the

performance and design direction of the Formula One car over the next decade. The Lotus 78 that was introduced in the 1977 season was the first in a succession of cars that employed the use of ‘ground effect’ as a means of producing far greater levels of downforce than was previously possible. The introduction engine design concept used by the Ford Cosworth DFV that was first used over a decade beforehand led to the possibility of ground effects as an aerodynamic tool. This was largely due to the V configuration that the DFV engine ran to. This factor was critical in the application of ground effect to the cars at the time, due to the fact that the V shape of the engine left plenty of space at the under body of the car, allowing teams to produce the ‘Venturi Effect’ with the design of the underside of the vehicle.

The use of ground effects transformed the Formula One race car from a chassis with wings attached; to what in itself was a whole wing ran upside down. The ‘Wing Cars’ as they came to be known employed the rules stated in the Bernoulli’s Principle to significantly improve the levels of grip which they were able to produce. This led to massive improvements in performance being found and lap times tumbling, becoming more like the times that we see today.

Formula One car design pushed the theory of the ground effect car to its very limit, creating dangerously quick machines for the time. One innovation that brought great increases in performance was the introduction of flexible skirts that ran at the bottom edge of each side of the car. These skirts formed a seal between the under body of the car and the outer body aerodynamics, massively increasing the potential of ground effects. Another example of teams pushing the theory of ground effects to the limit was seen in the Brabham BT46 fan car, that employed the use of a huge fan placed at the rear of the vehicle with the aim of greatly reducing the pressure of the air flowing on the under body of the car. The fan car only raced once, a race which it won, before it was quickly banned. This push in the development led to many drivers losing their life as a result of safety essentially being pushed to the side in the attempt to ascertain the greatest levels of performance from these ‘Wing Cars’. It was for this reason the FIA decided to ban the concept in the early 1980s, meaning its full potential was never truly unlocked, forcing designers to pursue other avenues in the quest for downforce.

3.5 Turbo EraThe Ford Cosworth DFV remained the engine of choice for most of the field up until the next major

step up in Formula One car design, more specifically engine design, was to appear in the sport towards the end of the 1970s.

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In 1977 Renault entered the sport, pioneering their 1.5L V6 Turbocharged engine, placing it in direct competition against the all-conquering DFV. Despite early troubles the Renault had become a proven race winner by the year 1979, forcing other teams to take note and rethink their ideas. As the technology behind the Formula One turbocharged engine progressed at a rate of knots the sport moved forward into the 1980s, the potential of the engine became apparent. As the use of turbos became more refined, allowing increasing amounts of power to be unlocked, the power disparities between the naturally aspirated and turbo charged engines became more and more evident, with vastly superior horsepower levels being possible whilst utilising the turbo engine.

This factor, along with the banning of ground effects due to safety concerns, led to the transition of the majority of the grid moving towards turbo power by the beginning of the 1984 season. The reason for this was the reintroduction of huge front and rear wings, that had largely disappeared during the previous era when the cars were basically one single wing, that was brought about as a means to make up for the loss of downforce that occurred as a result of ground effects being banned. These larger wings, although generating great levels of downforce, also created a lot of drag that hindered the cars top speed. Therefore the use of the turbo engines greater power enabled teams to claw back this loss in speed through engine power, making the transition from naturally aspirated to turbo-charged a near necessity.

The turbo era lasted for the next few seasons, with some quite staggering pieces of engineering produced towards the end. The final year of the turbocharged Formula One Car saw witness to cars capable of producing near 1200BHP, leading to speeds that were previously unthought-of in the sport. The ever increasing power of the cars at this time led to several revolutions of Formula One car being seen over this era, with the cars becoming far wider and chunkier to accommodate the powerful engine. This fact also saw the introduction of incredibly wide rear tyres as means of allowing the car to lay down its power, creating the defining image of F1 car that many envisage for the turbo era.This increase in speed and the rising cost of the turbocharged engine forced the FIA to ban the concept in the year 1987, forcing teams to move back to the naturally aspirated engines that had been used previously. This reversion led to far slimmer and streamlined Formula One cars being developed throughout the grid, once again placing the emphasis on the aerodynamics of the car as opposed to the power. This led to Formula One car design becoming far more similar to what we see at present.

3.6 Modern DayThe modern day Formula One car is in many ways the pinnacle of the design theory that was

introduced as a result of the banning of turbos, with a few minor changes being mandatory due to safety issues that cropped up over the last decade or two. With designers minds around this time firmly centred on improving the handling of their cars, a shift in the materials used to construct the various components of a F1 car occurred during this period, with teams starting to use the ultra-light material of carbon fibre for the first time. Initially the use of carbon fibre was pioneered by McLaren, who used the material in the construction of the monocoque for their highly successful MP4/1. Over the next decade the use of carbon fibre became widespread, with teams utilising the material in the construction of key components such as the suspension wishbones, chassis design, exhaust systems, diffuser and the entire bodywork of the car to produce far lighter breed of Formula One car.

The word safety has essentially been the defining reason cars look like they do today. The banning of turbos led to far greater thought being given to the aerodynamics design of the car. This led to incredibly refined aerodynamic features, such as multi decked front wings, barge boards, sculpted side pods among others, cropping up over the next few years.

The rise in electronic driver aids became apparent at the beginning of the 1990s, with many innovations that we see in road vehicles today, such as traction control and active suspension, being

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developed in Formula One at this time. Most of these aids were banned by the year 1994, a significant year in the history of Formula One car design. The death of Aytron Senna at the San Marino GP in 1994 forced the FIA to look into the safety concerns that were present in the F1 cars of the time. This led to many design features, such as higher cockpits which extend half way up the drivers head as to provide greater protection, that we see today becoming mandatory.

The next few years of car design were generally focused on slowing the drivers down and creating far safer vehicles. There was however still room for the creative minds to introduce a few interesting innovations and concepts to the sport in the search of greater levels of downforce. This created a Formula One car that looked somewhat a mess towards the end of 2008, with several aerodynamic features cropping up all over the bodywork.

This led to what is known as ‘dirty air’ becoming a serious issue in the sport. The greater levels of downforce that the cars were producing created far higher levels of turbulence in their wake than was previously seen in the sport, making overtaking difficult. This factor lead to the rules changes that we saw introduced in 2009 come into effect.

The 2009 rules changes transformed the Formula One cars into those we see today, far more streamlined and tidy vehicles, with a greater emphasis on the sculpting of the body work, particularly at the rear, and featuring wider front wings and taller rear ones. This set of rule changes also saw the introduction of KERs into the design of the Formula One car, a critical component looking to the future.

4. The Formula One CarSo as we discussed over the course of the previous chapter, the Formula One car as a whole is the

result of many decades worth of research and development centred on creating the quickest car that meets the rules and regulations of the time. During this chapter we will look at the various features that comprise the aerodynamic package of the Formula One car that we see today, detailing the several keys design areas of the vehicle that make it the pinnacle of motorsport.

4.1 Makeup of an F1 CarBefore looking at the aerodynamic package in greater detail, it would be best to identify the basic

makeup of a Formula One car as a whole. The Formula One car is, as it always has been, an open wheeled and cockpit, single seat race car. This means that the drivers head is always in the open and the suspension arms among other components are clearly visible externally. The overall design of Formula One car is governed by the rules and regulations set out by the FIA. This means that although the Formula One car is seen by most as the pinnacle of the automotive industry, it is by no means the true representation of the limit of automotive performance. In fact due to several technological advances that have appeared in the world of Formula One over the years being banned, the makeup of the cars that we see today is relatively simple compared to what would be possible if there were no rules.

When thought of from the bare basics the Formula One car as a whole can be broken into three key sections. The first being the front structure of the vehicle, here we find the front wing, nose cone and front suspension system. The design of the front section is critical when determining the aerodynamic properties of the car, as the manner in which the air is able to flow over this area of the car will dictate the flow over several other areas of the car. The middle section of the Formula One car is very much the heart of the operation, not least because this is where the driver will be placed. In this area we find the chassis of the vehicle in which the cockpit and survival cell are placed. Directly behind this the engine is found which is encased in the engine cover featuring an air box at the tip. The fuel tank is located at the bottom end of the chassis. All these

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features are tightly packed in-between two side pods either side of the car which again are critical to the aerodynamics and cooling of the vehicle.

The rear section of the Formula One is generally the area which generates the greatest levels of downforce and is vital in ensuring that the car remains ‘planted’ to the ground. Along with the rear wing, the back section of the car also houses the rear suspension system and diffuser beneath. The diffuser is crucial to the cars aerodynamic performance, and has in recent years been the subject of much controversy. Finally a floor is located beneath the car that is heavily regulated to ensure that it remains flat, a rule that is necessary as a consequence of the banning of ground effects.

A Formula One cars performance will be dependent on all these different sections of the car working together as a complete package, with the design rarely being as simple as simply strapping one good design feature to a poor car in the hope finding performance. Having detailed the extremely basic makeup of a Formula One car we can now delve into several of these key design aspects of the aerodynamic package of the car that contributes massively to the performance of the car. Form here we can look into the principles behind each one, and see how they work in conjunction with each other to create the ‘complete package’.

4.2 Aerodynamic PackageEnzo Ferrari once said “Aerodynamics are for people who can’t build engines.” How wrong he has

been proven to be as the aerodynamics of a Formula One car is the single most important area that the designers will need to consider. As discussed earlier the aerodynamics features of a Formula One car have come a long way over the course of the last fifty years or so, featuring many different aerodynamic devices.

The crucial role that aerodynamics in producing the greatest levels of performance can be best explained in the recent quote by former F1 engineer Gary Anderson, who said “It's the aerodynamic side that gives you lap time. The mechanical side, generally, only lets you down. It loses races; the aerodynamic package is what wins races”.1Taking this factor to hand the design of a Formula One car will be centred on the aerodynamic performance of the car, with all features of the design built to work in conjunction with the aerodynamic package, not the other way round.

In order to design to the optimum aerodynamic package for the car, designers will be faced with the task of finding the correct balance as to ensure that the maximum levels of downforce are created whilst producing minimal amounts of drag. The aerodynamic package of the Formula One car will generally be designed from front to back. This is due to the fact that I mentioned earlier which stated that the car must perform as a package, not as several individual parts. Taking this into account the under body of the car will need to be designed to deal with the specific air flow that is generated from the front wing, with the rear wing utilised to create further downforce from the up wash generated by the floor for example. The two key aerodynamic features present on a Formula One car are the two wings and the under body, that consist of the floor and diffuser, which contribute towards the majority of the downforce produced. This is not to say that they are the only areas given thought, in fact every single exterior component and surface of the F1 car will be sculpted for optimum aerodynamic performance. There are several key features of the aerodynamic design of the Formula One car, each of which has a major impact on the performance of the car as a complete package.

4.2.1 Front/Rear WingsThe front and rear wings have become synonymous with the modern day Formula One car and are

visibly the most immediately obvious aerodynamic feature of the vehicle. Due to the present day regulations banning ground effect; the wings of a Formula One car are the areas from which the greatest levels of downforce are generated. It is estimated that 60% of the downforce that a Formula One car generates is as a result of its front and rear wings.

1http://www.bbc.co.uk/sport/0/formula1/20844843

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Front WingThe front wing is considered by some to be the single most important feature of a Formula One cars

design in terms of contributing to the overall aerodynamic performance of the vehicle. The reason for the front wing being of such importance to the design of the car as a whole is due to the fact that it is the first part of the car that comes into contact with the air around itself.

As a consequence of the front wing preceding all other components of a Formula One car design, it will dictate the manner in which the air will flow over all other parts of the car seeing as they will be in the wake of the air that has been worked by the wing. As a result of this the design of the front wing will have a huge impact on the aerodynamic efficiency of the car as a whole.

On its own the front wing produces roughly a third of the overall downforce of a Formula One car, with some producing as much as 500kg of downforce, meaning that it is the area in which teams will generally look towards in the hope of improving performance. However this performance gain isn’t always acquired through increasing the amount of downforce generated by the front wing, with many teams needing to make compromises on the design of their front wing as a single component so to improve the flow of air over the rest of the car. This fact is clearly evident in the front wing designs that we see on the grid today, with many teams’ showcases incredibly complex looking solutions, many of which consist of three or more elements, with the aim of optimizing the flow of air that travels over the rest of the car. In fact a simpler design of two elements would yield higher levels of downforce, but with the downside of impeding the air flow over the rest of the car, a clear indication that the design of a front wing is far from simply centred on generating the greatest amount of downforce. These intricate modern day designs are a result of thousands of man hours being put into analysing every aspect of a front wings design, this vast research leading to the incredibly complex solutions that we see on the grid today, which is a far cry from the single plane wings that we saw initially used in the sport.

The general construction of the front wings that we see today consists of a main plane which on its own acts as an aerofoil. Upon the main plane several layers of flaps are placed, the amount of which is dependent on the desired downforce levels. At each side of the main plane an end plate is found. The end plate plays a crucial role in the aerodynamic efficiency of the Formula One car as a whole, its first job being to keep the flow of air over the front wing confined within the main plane and over the flaps, preventing any air from spilling over the sides. As well providing control of the air flow over the front wing itself, the end plates are also designed as to force the flow of any turbulent air away from the car, preventing it from disrupting the aerodynamic performance of other areas such as the diffuser.

So from a design point of view the front wing is the most critical aerodynamic feature of the car, having a huge bearing on the overall performance of the car. Figure 4.1 demonstrates this, showing the effect that the front wing has on the air flow and how it is used to simultaneously produce downforce and optimise the air flow for the rest of the car. Another important factor to consider is that generally speaking the regulations regarding the design of a front wing are quite relaxed in comparison to other areas of a Formula One car, leaving room for designers to be far more creative in their thinking, another reason as to why it is so crucial.

Rear Wing

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Figure 4.1 sidepodcast.com



As a single aerodynamic component the rear wing of a Formula One car can generate more downforce than any other area of the car. Red Bull claim that their rear wing ran at its highest downforce setting is capable of producing in excess of 1000kg of downforce; double that of the front wing. However as a result of the rear wing being placed at the very rear of a Formula One car, it doesn’t have quite the same bearing on the overall aerodynamic package, and can be seen more as an individual component. This isn’t to say that the design of the rear wing will be performed independently from that of other features of the cars aerodynamic package, as the rear wing will still need to be optimised to work as efficiently with the flow of air that is produced by the preceding aerodynamic features on a Formula One car.

Rear wing design has been fairly basic in comparison to that of the front wing over the years, with regulations in place to limit the number of elements present on a Formula One cars rear wing to two. The two elements of a rear wing are crucial to the design as the slot that is created as a result helps to speed up the flow of air running on the underside of the wing, preventing the wing from stalling. If the rear wing were to stall a dramatic loss of downforce would occur, potentially causing the driver to lose complete control of the car.

The principle in which the rear wing is able to produce downforce is achieved through the shape of the wing, which is designed to create a situation where the air flowing underneath the wing is accelerated to a greater velocity than that which is travelling over the top. This creates a difference in pressure, with the air flowing under the wing lower than that over the top, which results in the wing being forced into the ground.

Aside from the two element wing placed at the top of the rear wing structure, the use of a beam wing located lower down the structure just above the diffuser also helps to generate downforce and keep the flow of air over the car at an optimum.

From a set up point of view the angle the rear wing can be adjusted as to either increase or decrease downforce, with the steeper the angle of the wing the greater the downforce will be, whilst also producing more drag which will limit top speed. Like the front wing the rear wing is encompassed in-between two end plates that operate to improve the flow of air over the rear wing elements, as well as playing a crucial role in the reduction of drag by limiting the size of the vortices created at the wing tip, as shown in figure 4.2. Some teams run rear wing end plates that extend past the rear wing structure and continue towards the floor of the car, the purpose of which is to form an extension of the diffuser, another critical component in the aerodynamics of a Formula One car.

4.2.2 Floor and DiffuserAfter the front and rear wing, the floor and subsequent diffuser of a Formula One car are the next

crucial aerodynamic features of the design. Although not immediately obvious to most, the floor plays a vital role in the aerodynamic performance of the car. In fact in terms of individual aerodynamic efficiency the floor is the most effective component, producing high levels of downforce with little drag created as a result.

Due to the banning of ground effects, the design of a Formula One cars floor is heavily restricted, with rules in place to prevent the floor from being located below a certain point. This rule is enforced via the use of

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Figure 4.2 shell.com



a plank placed on the underside of the floor, with the rules stating nothing must protrude further down than this plank. This rule obviously limits the potential downforce that could be created from the floor as there would be a step in the floor as opposed to the desired flat floor for optimum performance. The crucial role that the floor plays in the overall aerodynamic package of the Formula One car is evident in the way that much of the design put into the front wing will be to optimize the flow of air under the floor of the car.

The application of the floor of a Formula One car to produce downforce centres on replicating the venturi effect between the car and the surface of the track. As we know the venturi effect occurs in a situation when a constriction or throat is present in the path that the flow of air will follow. This constriction will cause the air to accelerate creating a pressure drop. This acceleration is seen in figure 4.3 where the greater velocity of the air flow under the car can be seen in CFD. In terms of a Formula One car, the area between the floor and the surface of the track forms a constriction that the air flowing past the car must past through. In this situation the front wing acts as the inlet to the venturi, directing the air under the floor. As the air enters the constriction between the floor and the track, the pressure drops from where it will reach the diffuser that will then take control of the air flow.

In the same way that downforce is created by the rear wing, the lower pressure of the air running under the floor in relation to the air flowing over the body of the car will result in downforce being generated. Essentially then the more the air flowing under the floor can be accelerated, the greater the levels of downforce generated will be, hence the importance of the front wing design plays in directing the air under the floor.

One recent method teams have employed to increase this rate of acceleration is to run the cars at a considerable rake, so as to have a higher ride height at the rear to that of the front. This has the effect of increasing the venturi that the floor will create. The floor of a Formula One car is sculpted as to work the air that flows from the front wing as effectively as possible. For this reason it is common to see what is known as a ‘tea tray’ protruding from the front end of the car under the nose, helping to improve the flow of air under the floor.

The floor as a single component will not generate downforce without working in relation with the front wing, diffuser and then finally the rear wing. The diffuser therefore plays a pivotal role in the effectiveness of the floor and the aerodynamics of the car as a whole.

The diffuser plays the role of releasing the accelerated air from the venturi that is created by the floor, and allowing it to return to its natural pressure. Taking this into account and knowing that the more the air underneath the floor can be accelerated, it is therefore clear that the quicker the air can be drawn from under the floor, the faster it will accelerate, in turn creating more downforce.

The diffuser is constructed from carbon fibre to make it as light as possible, consisting of an upwards curve with several strakes protruding from this curve towards the track. These strakes play an important role in the way that the diffuser controls the flow of air at the rear of a Formula One car, as they are placed to ensure that the air is able to leave the venturi as smoothly as possible. The upwards curve of the diffuser acts

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Figure 4.3 racecar-engineering.com



to gradually increase the gap between the tracks surface and the floor, allowing the air to decelerate and return to normal pressure. The diffuser can contribute up to 30-40% of the total downforce generated by a Formula One car, and has for this reason been the subject of much design innovations over the past few season, which I will look into later in the project.

The relation between the diffuser and floor is crucial to the overall balance of a Formula One car as a small adjustment to one can have a major impact on the performance of the other. Generally the downforce generated by the floor will contribute towards the front end grip of the car, with the diffuser heavily focused on rear grip. Therefore the design of both components will need to be tailored to each other to ensure that they interact as efficiently with each other as possible. Taking this into account any design improvements made to the diffuser will need to be implemented to ensure that the floor is able to accelerate the air at an improved rate as well, maintaining the balance in grip, as if there was to only be an increase in downforce generated by the diffuser, then only rear grip would be added, causing an imbalance.

4.2.3 Other areasThe front and rear wing along with under body of a Formula One car generates the majority of the

downforce that is produced, however there are many other areas of the car that are designed with aerodynamics in mind, even if that is not their primary function.

Chassis DesignThe chassis will form the basis of all Formula One cars and although most of its structure will be

covered by bodywork, it is still not void of aerodynamic features aimed at improving the flow of air around and more specifically under the car. Many teams now sculpt the area of the chassis that is visible underneath the driver, known as the keel, to optimize the flow of air that enters the under body of the car at the ‘tea tray’ section and progresses through the floor and onto the diffuser and rear wing. For this air to reach the floor it will obviously need to negotiate its way around the sides of the chassis. For this reason the keel is shaped, in most cases to a ‘V’ configuration to aid this flow of air past the chassis.

Side podsThe primary function of the side pod is to act as a home for the engine cooling radiators, a concept

that first was introduced by Colin Chapman with the revolutionary Lotus 72 that was the first to use side mounted radiators. Clearly the side pod poses as a significant obstacle to the flow of air over and around a Formula One car. For this reason the design of a side pod has become ever the more refined over the years. Recently the trend of side pod design has moved towards creating a very narrow rear end to the car. This has been termed the ‘coke bottle’ section as the side pods can be seen to, in some designs, very aggressively curve inwards towards the rear. This ‘coke bottle’ helps to reduce the amount of drag created from the side pods as well as help to optimize the flow of air over the rear tyres and onwards towards the rear wing.

Modern side pod design has also seen the introduction of a carefully sculpted undercut at the base to improve the flow of air towards the rear end of the car, more specifically help to keep the air attached to the car and deliver it onto the diffuser. Some teams have also experimented with using different shapes of side pods, such as the McLaren MP4-26, which feature ‘L’ shape side pods in the effort of improving the flow of air over the rear beam wing. This season has seen Sauber experiment with the use of an extremely narrow side pod design in the attempt to reduce drag, another example of the on-going research into the aerodynamic importance of the design of a side pod.

Barge BoardsBarge boards and other appendages came to the forefront during the 2000s, with many different

devices appearing on cars up and down the grid in the search of generating further downforce. Eventually these devices were seen to have extremely intricate designs, some looking decidedly ugly. In the effort to

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reduce the impact of turbulence air and aid overtaking the use of these devices were severely restricted from the 2009 season onwards. As a result of this the barge boards we see on the grid today are far more basic and less effective than those a few years back.

Despite this the barge boards on a Formula One car still play a significant role in the overall aerodynamic package. The barge boards play the role of directing the turbulent air caused by the front tyres away from the car, as well as helping to keep the air flow from the front wing and ‘tea tray’ are attached to the car and direct the flow onwards towards the side pods.

SuspensionAlthough clearly not an aerodynamic device primarily, due to the open wheeled nature of a Formula

One car the suspension arms present in the suspension system have a significant impact on the aerodynamics of the car as a whole. Although there is little to no downforce produced by the arms themselves, it is important in there design to reduce the amount of drag that they produce.

For this reason the design of modern day Formula One cars suspension wishbones has become ever the more streamlined and ‘slippery’ in the effort to ease the flow of air passing over and through them reducing the levels of drag. Another key design decision, from an aerodynamic point of view, that will be necessary during the inception of a Formula One car is whether to use a pull rod or push rod suspension layout. The pros and cons of both is a separate topic, but for aerodynamic purposes the use of a pull rod layout can aid the aerodynamic properties of a Formula One car due to fact that the rod will not be as much of an obstruction to the flow of air. This factor has seen the use of pull rod suspension re-emerge in the sport in recent years, starting with the Ferrari F2012.

Engine CoverThe engine cover of a Formula One car obviously poses as a major aerodynamic dilemma in the design

of a Formula One car. The shape of the engine cover is generally directed by the engine, air box and gearbox size and location, as well as needing to meet the dimensions stated in the regulations. For this reason the design of the engine cover will be aimed at optimizing the air flow over this part of the car and helping to direct it onwards towards the rear. Other than keeping the design as streamlined as possible as to reduce drag, there is not any downforce generators located on the engine cover due to the regulations.

Recent years saw the use of what was known as a ‘shark fin’ engine cover in the effort of reducing the cars yaw sensitivity and improving the stability of the car under braking and at the rear end by creating an easier path towards the rear wing for the flow of air to follow. However the FIA moved to effectively ban these ‘shark fins’ for the 2011 season by introducing a rule that designated an exclusion area in front of the rear wing where no bodywork is allowed.

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5. Design ProcessThere are very few other engineering environments that feature the same challenges involved as that

of the task of designing a Formula One race car. To start with the rules and regulations of the sport are in a constant state of upheaval, with periods of relatively consistent set of regulations regarding car design a rarity. This obviously forces designers into constantly rethinking their ideas in many cases, as quick as a genius innovation or design solution is born, it is then subsequently banned.

As well as the changing regulations that designers must contend with, the technology used both during the design process and actually on the cars themselves and trackside is rapidly progressing, with Formula One being one of the most technologically advanced engineering fields on the planet. Because of the great challenge involved in designing the modern day Formula One car, the man power put to use has grown exponentially over the course of the championships existence. The days of a Formula One car design and construction being carried out by a small team, sometimes consisting of two or three people, has long gone. Instead nowadays an entire team of hundreds of individuals are tasked with the job of designing the car, due to the levels of complexity involved.

In order to work as efficiently and effectively as possible the design team is generally split into two particular groups during the design process. One group is responsible for the mechanical design of the car. This involves designing and constructing the chassis and mechanical components like the suspension system, steering, gearbox among many others. In most cases the engine of an F1 car is not designed or built in house, rather supplied by a road car manufacture, such as Renault, which will work in partnership with the F1 team to develop the engine. However due to the engine freeze that has been in place within F1 for the past several

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seasons, this area of Formula One car design has been stagnant, with little allowances given to improve the current breed of engines.

Once the mechanical team has designed the inner workings of the car, they can pass on the necessary dimensions to the second design group which is tasked with producing the aerodynamic design of the car. Essentially the Aerodynamic team of designers will be given the inner skeleton which they can then cover with the bodywork and then attach to it the required aerodynamic features like the wings.

With a Formula One car containing over 3,500 individual components the design process involved is obviously an extremely complex task. The design of the aerodynamic package of a Formula One car on its own is a massive undertaking which involves several stages, each of which is crucial to the final performance of the completed design. Each stage in the design process of the aerodynamic package is carried out with upmost detail and dedication to ensure that the maximum potential of the car is reached. With the aerodynamic package contributing massively to the overall performance of a Formula One team, vast amounts of resources and knowledge is poured into the design process in order to allow the aerodynamicists among the design team to utilise the very latest advancements in design tools and technologies.

5.1 Initial Design/ConceptionBefore any design can be put into practice, the initial ideas and theories that the design team will

have floating around in their minds will need to be put on the ‘drawing board’ in order to create a starting point for the design. This isn’t to say that the initial designs will be made by hand, with very few still choosing to use this method, although it must be noted that one of the last remaining designers to still hand draw their ideas is also arguably the greatest to have ever been in the sport, Adrian Newey, who in his own words describes himself as “the last of the dinosaurs”.

Before any new parts or ideas are created virtually, the lessons learned from the previous year’s design will be laid out on the table to form the initial targets for the new car, as any drawbacks of the previous year’s design would not want to be carried over onto the new car. To go alongside these objectives, the design team may also have new concepts in their minds, or that they have seen on other teams cars, that they wish to incorporate into the new design. Again these will need to be added to the drawing board. Obviously the regulations regarding Formula One car design tends to vary from year to year, so any new regulations will also need to be considered on the drawing board before a starting point can be conceived.

Having taken all the above into consideration, the design team will have been able to produce an initial concept of the basis of the car that they wish to build, creating a visual idea of the location of the key components, such as the gearbox and engine, location within the vehicle. From here two critical parameters to the design of the car can be determined, both of which will dictate the final design.

Firstly the centre of gravity of the new vehicle will need to be identified, with this point on the car providing the place where the weight of the car will be concentrated. When drawing up the initial design for the new car, the design team will want to place the centre of gravity as close to the bottom of the car as possible, in order to create a more stable and balanced design. The centre of gravity will be determined by the distribution of weight between the front and rear of the car, and the top and bottom.

The second parameter that needs to be set is the centre of pressure on the car. This point is crucial to the aerodynamic design of the car as it is the place where all the aerodynamic forces acting on the car will be at its most concentrated, in other words the part of the car that will be being forced into the track. This obviously means that the closer to the centre of the car the more balanced and drivable it will be. The centre of pressure will be determined by the positioning of the aerodynamic features on the car, therefore having

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come up with an initial concept for the design of the car, the exact location of the aerodynamic features can then be fine-tuned in this initial design to create the optimum position for the centre of pressure.

5.2 CADHaving determined the initial concept for the design of the car, and having set the necessary design

parameters, the design team will then be able to proceed to realise these design ideas in a virtual sense. Whereas before these designs would have been produced by hand, hence Adrian Neweys use of the word “dinosaurs”, the initial designs for the modern day Formula One car are carried out with the use of CAD.

All areas of a Formula One cars design will be realised in a CAD environment, with teams using the very best CAD packages, such as NX and Catia. CAD provides a 3D virtual environment in which designers can move their ideas into reality, without incurring the cost of physically constructing the component. CAD is used to create the initial design of all aspects of a Formula One car, however it is in regards to the aerodynamic design of the car where its potential is realised to great success.

With the initial design conceived, the relevant data is then passed on to the CAD engineers who produce a virtual 3D model of the design in CAD. Each individual feature of the aerodynamic package for a Formula One car will be produced in CAD, with massive emphasis put on the accuracy of the models, as any slight differences between the virtual model and its real life counterpart could render any subsequent data, which is obtained during the design and testing process, useless. Each part created within the CAD environment will be thoroughly tested and validated to ensure that it conforms to the dimensions and geometries that were set during the initial design and enable the predetermined design parameters to be maintained.

With the initial design concept produced and validated in CAD, each component is then brought together to create a complete 3D model of the final design. It is from here that the first major benefit of CAD becomes apparent. The construction of the modern day Formula One car is almost entirely performed through a process called computer aided manufacturing. Designers will be able to pass on the CAD model to the construction team from which the new cars construction can begin to take place through the use of the CAD data. The CAD data is used to control the CAM machines, such as a CNC machine, to individually construct the majority of the components, both aerodynamic and mechanical, that make up a Formula One car.

However before the construction of the aerodynamic package can commence, the aerodynamicists within the team will look to perform an analysis of each component of the completed CAD model. This aerodynamic analysis of the CAD model is carried out through the use of computational fluid dynamics, or CFD.

5.3 CFDIn recent years CFD has become an invaluable tool that has become a vital part in the design process

of a Formula One car. CFD involves the use of fluid dynamic equations to perform detailed analysis of fluid flow within a system, and seeing as air is a fluid it can be used to analyse the flow of air around a Formula One car. CFD was first used in the sport of Formula One in the 1990s, and with modern computers becoming ever the more powerful, with this increase in power being far cheaper to purchase, the use of CFD has become widespread in the design process of a Formula One car.

CFD is used in conjunction with CAD in order to analyse the aerodynamic properties of the 3D model, creating vast amounts of data that give an initial reflection on the aerodynamic potential of the new design. CFD allows designers within Formula One to perform detailed analysis of any component of the design of their car, meaning that the component can then be tweaked, through use of the data ascertained from the CFD simulation, within the CAD environment in order to improve upon and fine tune the final design.

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CFD allows the aerodynamicists to perform a simulation of the aerodynamic forces that will be acting upon the car. The data produced from this simulation will allow design team to gain an understanding of downforce levels that the new design could potentially achieve. From this data the design team will be able to identify areas of the design that can be improved upon in order to produce more downforce. This benefit of running simulations, and obtaining feedback on the design very quickly, means that the model can be constantly modified before it is sent for construction.

The key to CFD providing such a useful design tool is the visualization, in the form of 3D graphics as seen in figure 5.1, of air flow over the CAD model that it provides to the design team. The data produced by the CFD simulation is then translated by the CFD software in the form of this visual representation of the air flow, allowing the designers to actually see what is happening with their design. This is vital as it allows designers to optimize certain components, such as the front wing, to improve the flow of air running over the whole car The visual representation also displays the relevant pressure and velocity values that would be present at each area of the model, meaning the design team will be able to see whether there theories will actually produce the desired effect in reality.

CFD is particularly useful in the design of new innovations or concepts that designer may visualize in their minds, but cannot replicate in a wind tunnel environment. One example of this is the blown diffuser that uses exhaust gases to improve the flow of air over the diffuser, a situation that cannot easily be tested in the wind tunnel due to air temperature and density differences to those that would be seen in reality. However such a scenario can be simulated using CFD, as such the innovation can be realised in the CAD environment and then tested through the use of CFD to determine whether it has potential or is better left alone.

CFD has become such a powerful tool in recent times that some race cars within the motorsport world have been entirely designed through the use of CFD, bypassing wind tunnel testing altogether. This method of design has seen some success stories, such as the Acura ARX-02A LMP car that won multiple races in the American Le Mans series. However with the complexities of designing a modern Formula One car, this success has not been replicated in this sport. The Virgin Racing VR01 is an example of a F1 car designed fully in CFD, which was terribly slow in comparison to other cars on the grid, proving that CFD cannot be fully trusted. For this reason CFD is used hand in hand with wind tunnel testing.

5.4 Wind TunnelMost of the initial aerodynamic evaluation of a Formula One cars design will be carried out through

the use of CFD. Wind tunnel testing is then performed on the design as a means to verify the numbers and air flow that were seen in the simulation. Wind tunnel testing will allow the aerodynamicists to see the real downforce levels and air flow that the design will produce, and from there fine tune the final design to iron out any issues that may not have been seen in the CFD environment.

The reason for using CFD for the majority of the evaluation process is the increased cost and difficulty of modifying a wind tunnel model in comparison to a CAD model. Wind tunnel testing is carried out through

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Figure 5.1 www.eng.fea.ru



the use of scaled models which are generally 60% the size of a finished Formula One car, mainly due to the extra cost involved in producing a full scale model. The disadvantage of using scaled models in the wind tunnel, as opposed to a full size replica, is the fact that there will be minimal differences of the aerodynamic properties of the air surrounding the model compared to that of the air that would surround the actual working car. One example of this is the boundary layer on the scale model, which will be thinner than that on the real car; as a consequence designers will take issues such as this into account when analysing the data obtained from the wind tunnel.

The scaled models used in the wind tunnel, despite the differences as mentioned above, are still an exact replica of the final finished design that would hit the track, just 60% of the size. These models are created through the use of a method called rapid prototyping that can be used to produce a physical construction of the 3D CAD model that would have been drawn up during the design.

During the operation of the wind tunnel the scale model is suspended from the ceiling in order to create a weightless model, meaning that only the aerodynamic forces acting on the model will be shown in the final results. As well as this wind tunnel test will be run with replicas of the pneumatic tyres that would be used in reality, so to ensure that the readings taken from the test take the deformation of the tyres that will be seen on the track into account, this is crucial as this deformation would affect the airflow over the rest of the car. Once the design is verified and fine-tuned in the wind tunnel the CAD models can be sent for construction in preparation for the final stage of the design process that will be performed, the track testing.

5.5 SimulationRecent years has seen the use of simulation tools, such as a driver simulation, become an integral part

of the design process. Once the design of a Formula One car is evaluated through the use of CFD and wind tunnel testing the numbers obtained from these can be use alongside several complex mathematical models to run a simulation of how the car will perform on the track. This simulation, although primarily for the drivers benefit, can be put to use to gain a better understanding of how the various aerodynamic features of the design may affect the handling and characterises of the car in reality. A simulation will also give the driver an opportunity to give the design team initial feedback on any design modifications that they may be developing, as the driver will be able to identify the impact that these changes will have on the handling of the car.

5.6 TestingThe final part of the design process will be undertaken during the designated test session that takes

place at the beginning of each season. With the days of unlimited testing within Formula One long gone, teams will need to make the most of the little testing that they are permitted to perform to ensure that they can fully evaluate the new design on track. The aerodynamic package will be thoroughly tested to confirm that the data obtained during the previous stages of the design process was correct, and that the car meets the predictions that would have been made from this data. The testing of the aerodynamic design of the new car will allow the team to identify the initial strengths and weakness that the car may possess, providing a path for any further development to follow. As is the rapid rate at which the development of a Formula One car takes place, several features of the aerodynamic package seen during the test will have already become obsolete, replaced by improved versions that were developed as a result of the information gained from testing.

Similarly to wind tunnel testing, on track testing will provide a form of validity to the design concepts that were conceived and then tested in the computerised environments of CAD and CFD, with the designers able to determine through the use of tools such as Flo Viz, the flow of air over the car and the workings of all

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the different aerodynamic features. Another key aspect of the testing performed on the new car is the driver feedback that the designers will receive. The driver’s feedback will in many ways provide the most important information that the designers will be able to use in the continued development of the aerodynamic package, as they will be able to confirm whether the numbers that the design team were seeing during the initial analysis were indeed correct. As well as this the drivers will be able to give a first-hand description of the impact that certain aerodynamic features have on the characteristics of the car, allowing the design of the car to be tailored towards a drivers particular needs.

5.7 DevelopmentA Formula One car is never truly a representation of the finished article, with constant development

of the aerodynamic package being undertaken by the design team throughout the season in the effort to squeeze even the smallest amount of extra performance from the car. This factor obviously has a crucial bearing on the direction that any research and development of a Formula One car will head during the course of the season. Most of a team’s design resources will be pumped into improving the aerodynamic performance of the car, once any initial mechanical issues that could cause reliability concerns are ironed out and rectified during the initial testing and early season races.

Any development work carried out on the aerodynamic package of a Formula One during the season will generally follow the same process that I have detailed in this chapter, but in most cases the analysis would be more focused on the particular area that the development concerns. The testing stage of the development would need to be carried out during the practice sessions preceding the races as opposed to at a specific testing event, due to the ban on in season testing.

The development of the aerodynamic package will be a continuing process over the course of the season, and will form the basis of the initial design for the following season as the team learn more about the car. During the season many issues and possibilities for improvement will become evident, which will determine the direction that the development of the car will follow. For example a fundamental problem with the front wing that affects the flow of air over the car, could arise during the first few races, leading to the development of either a completely new wing, or modification to the current one, in an attempt to rectify this problem and improve the car.

6. Design Innovations over the YearsFormula One has a steeped history, as discussed earlier in the project, and much of this history has

been shaped by the various design innovations that have been introduced by the leading minds in the sport over the years. Most of these innovations have been in the attempt to extract greater aerodynamic performance from the cars, with some being ingenious and becoming the standard throughout the grid. However there have also been many that have, although had their benefits, proved to be fundamentally flawed or even illegal and subsequently thrown in the bin or, in most cases, banned by the FIA. During this chapter several of these design innovations will be detailed, looking at the impact each had on the sport and its lasting impact.

6.1 Chapman LegacyColin Chapman is a name well known to fans of the sport, with him having legendary status to those

in it. Chapman introduced several innovations that helped shape the Formula One car into the ones we see

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today. Many of his ideas lead to the revolutions in the way that the Formula One car was built, as we discussed earlier, however it was in the aerodynamic design of the car that he really stood apart from the rest.

Chapman, along with several others of the leading designers of the time, brought about the concept of aerodynamics to the sport, the introduction of which dramatically changed the look of the cars forever. Chapman was, although not the first to use, one of the first to correctly utilise the front and rear wings in order to produce a positive aerodynamic downforce, the theory of which is obviously still a major part of the design of a Formula One car. Alongside the correct use of wings, Chapman introduced the side pod as an element of Formula One car design, greatly improving the aerodynamics of the cars at the time. As well as these innovations, Chapman was the first to use the wedge like shaped for the design of the car, an innovation that shaped all subsequent Formula One cars.

The introduction of ground effects was perhaps the greatest innovation that Chapman can be thought of as responsible for. Ground effects completely changed the face of Formula One design until they were eventually banned. It is almost certain that if not banned, the theory behind ground effects that Chapman introduced would still be in use today as is the aerodynamic efficiency of the method. Chapman really pushed the theory of ground effects to the limit, introducing innovations such as side skirts, dual chassis and wingless cars that produced all their downforce from ground effects, eliminating the issue of drag. Chapman died before the end of the ground effect era, but no doubt would have introduced countless more innovations had he been alive today.

6.2 Shape Defining InnovationsAlongside the Chapman legacy there have been many innovations over the years that have

contributed to the vastly improved aerodynamic design of the modern Formula One car. Most of these innovations have come about in the period since the banning of turbos, with the increased knowledge in the field of aerodynamics resulting in a far more refined design. Adrian Newey was the first to place a major emphasis on the aerodynamic packaging of one of his cars in 1988, with the March 881 looking far more tidy and compact than the other cars on the gird at the time. The extremely streamlined look of the car was followed by all other teams over the next few years. Another innovation that was first seen in the sport around this time was the introduction of the high nose design that is common place on the cars of today. Tyrell pioneered the use of the high nose with their 1990 challenger, the 019, after discovering that the aerodynamic effect of the floor and diffuser could be improved upon if the nose was to be raised, creating a more direct path for air to flow under the car. This design innovation has also lead to the improved aerodynamic design of suspension systems adopted by the Formula One car, as the higher nose has allowed for the location of the mountings to be moved higher up the chassis as to improve the flow of air, underneath the car further.

6.3 Short-lived/Banned InnovationsAs well as the design innovations that have, over time, become part of the standard design philosophy

of the modern Formula One car, there have been several seen over the years that for one reason or another were banned by the FIA:

6.3.1 Brabham Fan CarBrabham unveiled a radical change in the design of their BT46B at the Swedish grand prix in 1978. In

an effort to match the speed of the ground effect Lotuses of the time, but unable to shape the underside of their car in the same manner due to the Flat-12 engine they were using at the time, Brabham fitted a fan to the rear of the car with the intention of sucking air from under the car. This had the effect accelerating the air flowing under the floor, creating a pressure difference that produced enough downforce to match that of the Lotus.

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The Brabham fan car is a classic example of Formula One teams ‘bending the rules’ with the design of their cars. Brabham claimed that the fan was simply a cooling device for its engines, which was true as the fan did act to push air through a radiator mounted on the engine. However it was obvious to all in the sport that the fans main intention was to create downforce. The concept proved highly successfully, with the car winning its one and only race whilst the drivers described driving it as “unpleasant” but none the less was “like driving on rails”. However the innovation was short lived as due to protest by rival teams the FIA moved to ban the use of fans in Formula One car design.

6.3.2 Ground EffectsAs has previously been detailed in this project, the use of ground effect became widespread during

the late 1970s and early 80s. Ground effect proved to be far more effective than other methods of creating downforce at the time, with the development of the concept moving at a staggering rate during its short-lived use. As we have previously discussed, the theory behind the use of ground effects enabled designers to turn their cars into a single wing, generating vast amounts of downforce through the shaping of the floor in an effort to accelerate the air flow as quickly as possible, whilst incurring a minimal drag penalty.

Ground effects dramatically increased the performance of the cars of the time, with increasing cornering speeds causing considerable pain to the drivers, due to the increased lateral g force that they were placed under. Due to driver complaints, and safety concerns, the concept was banned for the 1983 season before it ever really reached its full potential. With the theory behind the innovation, aerodynamically sound, it would be fascinating to see what would be possible with the present day Formula One cars if the use of ground effects was to be reintroduced to the sport, as was briefly muted when the 2014 regulations were initially drawn up.

6.3.3 Active SuspensionAlthough a mechanical system itself, active suspension greatly increased the aerodynamic

performance of a Formula One car. The idea behind the innovation was to maintain a level ride height on the car whilst driving over the many rises and bumps on the track. The level ride height meant that the car was running at the optimum height for full aerodynamic efficiency at all times.

The concept was initially developed by Lotus in the 1980s, in an effort to extract the maximum potential of the ground effect theory that the cars of the time were designed around. The system developed by Lotus didn’t bring the performance gains that were initially expected, and the system was subsequently dumped by the team in 1988. The reason for this limited success was the issue of the computer technology of the time not being powerful enough to compute the data that the system was generating, meaning that the

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Figure 6.1 Ground effect on the Lotus 79B formula1-dictionary.net



system was reactive, in that it would react to the track undulations and then make the necessary adjustments, as opposed to an active system which would prepare the car for the bumps before it met them.

With the rapid increase in computing power, Williams were able to incorporate the use of Active suspension in the FW14B and FW15C to great success in the early 1990s. The system developed by Williams was far more advance than that of Lotuses, with the suspension far more active as it would make the required adjustment to the ride height before the relevant piece of track as the engineers were able to utilise the increase in computing power to program the elevation changes into the cars suspension system. Active suspension meant that the two Williams cars were far and away fastest on the grid, where they remained until the system was banned by the FIA, who deemed it to be a “movable aerodynamic device”. Presently several teams in the sport are developing what is known as front and rear interconnected suspension, or FRIC. This innovation promises to replicate the aerodynamic advantages of active suspension, allowing for a constant ride height to be maintained.

6.3.4 Mass DamperA recent innovation that was brought about in an attempt to keep the cars ride height closer to the

ground whilst driving over bumps in the track was the Mass Damper. Renault utilised the concept in the design of their R26 that won the world championship in 2006. The innovation enabled the team to dampen the pitching on the car that would occur whilst driven over bumps and kerbs. This meant that aerodynamic devices, the front wing in particular, were kept at a lower and more consistent height, resulting in far less of an aerodynamic loss caused by the front of the car rising as it encountered bumps. The innovations potential was clear as when the Mass Damper was banned during the 2006 season, Renault lost their edge over their competitors for the remainder of the season.

6.3.5 X-WingsA rather comical looking aerodynamic innovation that appeared over the course of the 1997 and 98

seasons was the use of the so called ‘X-Wings’ that many teams added to the side of their cars in an effort to achieve more downforce. The concept was pioneered by Tyrell in a desperate attempt to generate more downforce on their car, utilising a loophole in the regulations that enabled them to place the wings on each side of the car. The concept was picked up by several teams at the start of the 98 season, mainly backmarkers looking to gain performance, although the fact that Ferrari added them to their challenger signalled that the idea did hold promise. The wings did generate downforce, especially helping to keep the cars more stable; however this increase in downforce came with a rather large drag penalty. The FIA moved to ban the innovation on safety grounds during the 1998 season, too much relief of fans around the world.

6.4 Recent InnovationsAs well as the innovations from the past, there have been several intriguing innovations that have

appeared on the cars in the past few seasons in an effort to improve upon the aerodynamic performance of the cars even further.

6.4.1 F-DuctA Formula One cars straight line speed has always been limited as a consequence of the downforce

that they produce. This limitation in speed is cause by drag, so any way of removing this drag whilst maintaining the same levels of downforce would provide a great performance increase. One situation in

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aerodynamics that can lead to the loss of drag is when a wing was to stall, meaning the air flow would become disrupted.

When McLaren launched their MP4-25 for the 2010 season it featured a duct placed on the nose of the car, on the letter ‘f’ of their sponsors’ name, that allowed air to flow through a tube towards the rear of the car, as shown in figure 6.2. This flow of air would be used for cooling purposes in normal running, however by use of a hole in the cockpit; the air flow could be blocked from its usual route and be used to divert another flow of air that entered through the air box towards the rear wing. This air flow that passes over the rear wing would act to stall it, meaning that any drag that was caused by the wing would be lost. This would also result in a lack of downforce from the wing, however this was not an issue as it effectively be switched on and off by the driver. The F-Duct allowed the McLaren to ‘dump’ its rear wing drag along a straight, meaning that it would be able to travel with less resistance and subsequently a greater top speed, roughly a 3-4 mph increase.

6.4.2 Blown DiffuserRed Bull greatly improved upon a concept that was first seen in the late 1980s to introduce the blown

diffuser innovation with their 2010 challenger the RB6. The blown diffuser made use of the hot exhaust gases that exited the car to improve the effectiveness of the diffuser as a whole. The first part of the blown diffuser was the relocation of the exhaust exits that were moved to be placed behind the side pods in the coke bottle section, as to allow the exhaust gases to be blown onto the floor. The hot exhaust gases posed as a high pressured, high velocity air flow that worked to re energise the air flowing through the diffuser. This helped to maintain a more laminar and steady flow, creating more downforce in the process.

6.4.3 Double DiffuserWhen the new aerodynamic regulations were introduced for the 2009 season, teams up and down

the grid were left with cars that lacked up to 50% of the downforce of the previous year’s car. This reduction in downforce was largely as a result of far more stringent regulations regarding the design of the diffuser, with the aim of reducing the ‘dirty air’ produced by the cars that year. This lead to three teams, Williams, Toyota and Brawn GP, finding a loop hole in the rules that allowed them to run far more aggressive ‘double diffusers’ that allowed them to claw back some of this lost downforce. Brawn GP utilised the double diffuser most effectively, with their car featuring a large opening above the crash structure in the rear diffuser. This opening formed a secondary part to the main diffuser, creating a far larger and aggressive aerodynamic device. The upper opening was fed by two holes in the floor of the car that created a far greater expansion for the air to escape from the diffuser. This meant that the air running under the entire car was accelerated further, creating a greater pressure drop and generating more downforce. The performance advantage of this innovation was thought to be worth up to 0.5 seconds a lap, resulting in teams scrambling to implement it in the design of their cars.

7. ConclusionTo form a conclusion to the research collated, a brief look into an example case study of the CFD

analysis of an aerodynamic feature on a Formula One car was undertaken. By looking at such a study it will be possible to utilise the knowledge gained from the project to identify the ways in which the device produces downforce through the use of the aerodynamic concepts discussed earlier in the project. We will also be able to visualize and obtain a greater understanding of the effect on the air flow that the given aerodynamic device

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has, and the pressure values that are created as a result of this which will further help us to see how the cars create vast amounts of down force. Finally looking into the use of CFD analysis will help to put the research into the design tools used in the sport into some form of practice.

It is important to note that the case study itself was not undertaken by the author, rather used as a reference to reinforce the knowledge gained over the course of this project. All images were taken from the following: http://www.f1technical.net/forum/viewtopic.php?f=6&t=7384&start=75.

An example of a Formula One front wing was used as the subject for the case study in question. As we discussed in the previous chapters, the design of a Formula One cars front wing is critical to the air flowing over the entire body of the car, however for the purposes of this particular study, we will only be looking at the ways in which it individually manipulates the air flowing over it in order to generate down force as a single component.

Before looking at an analysis of an example front wing, firstly we will see how the base shape of a wing, an aerofoil, works to manipulate the air around it. The aerofoil of a front wing will be flipped from its natural rotation in order to produce down force as opposed to lift. An aerofoil is used as the basis of a front wing design due to its low coefficient of drag, around 0.04, depending on its angle of attack, meaning that it can generate high levels of down force with little drag penalty.

The basic way in which the aerodynamics of an aerofoil works to produce down force can be demonstrated using NASA Foilsim III. As you can see from the screenshot below, the aerofoil manipulates the airflow to accelerate the air flowing underneath, creating a higher pressure on the top surface than at the bottom, which as we discovered earlier leads to the wing being pushed into the ground. This downforce is shown as negative lift in the screenshot:

The above screenshot is representative of a Formula One wing in an average degree of attack. If the angle is increased, then the downforce and drag will simultaneously increase, with a flatter wing creating less downforce and drag. This is shown in the screenshots below:

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As you can see the greater degree of attack creates far more downforce. Finally we can use this simulation to observe the Coanda effect more clearly by changing the camber of the aerofoil:

As you can see the air flow follows the curvature of the underside of the wing very aggressively. This curvature allows for a stronger force to be created courtesy of the Coanda effect, meaning that the air flow accelerates far quicker and in turn creates more downforce. Finally we can observe the ways that the air flow remains attached and realigns with the flow running over the upper surface.

Having looked at the basics using Foilsim, we can now look at an example CFD analysis of a front wing design. Below is a shot of the basic wing used in the analysis:

This shows the pressure map of the basic shape, with the high pressure zones found at the leading edge of the three elements that make up the wing. Now we can look at the ways that such a design would manipulate the air flow over it:

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In the two above shots we can see how the shape of the wing affects the flow of air, as the laminar flow that meets the leading edge of the wing is disturbed and becomes turbulent. This area of analysis provides an ideal visualization of the importance of the front wing design in creating the optimum air flow for the remainder of the car, as the turbulent nature of the flow that leaves the front wing will not be ideal for the rest of the car. On the shot below we can observe the coanda effect in practice as the air flow follows the curvature of the front wing end plate, as well as on the upper and underside of its surface, allowing the stream to realign.

Having looked at the air flow streamlines, and seen in practice how the front wing diverts the flow of air, we can now look at the effect that this has on the velocity of the particles in the fluid:

As you can see from the above shot, the air flow is rapidly accelerated on the underside of the wing, with the red zones at the outer and inner edge of the two main elements indicating the areas where the air flow reaches its greatest velocity. We can see in the previous shots on the last page that this greater velocity also acts to increase the turbulence of that particular point in the air flow, with the flow leaving the wing in a far unorganised manner than other areas. Finally the area of low velocity on the upper surface of the main plane is clearly seen in the middle of the wing, shown in the dark blue section. Finally to finish of this basic conclusion we can look at the culmination of the analysis to see how all of the above works to create downforce by forcing a pressure difference between the upper and lower surface of the wing. As you will notice the design of the wing has been improved upon from the initial concept that was analysed in the previous sections, with this change being brought about from the data obtained from the previous CFD simulations.

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This first shot shows the pressure map on the upper surface of the wing. As you can see by use of the chart on the right the main elements on each side of the wing work to increase the pressure on the surface. The areas of highest pressure can be observed on the leading edge of the three elements, as a result of the stagnation that occurs at these points.

Finally the above shot shows the pressure map on the underside of the wing. Clearly we can see the culmination of the front wings work as the accelerated air flow on the underside has created a far lower pressure zone on the surface. The pressure slightly increases as to be expected as the air flow becomes separated from the wing and gradually returns to free stream velocity. The two previous screenshots provide the perfect visualization to the reason why the air flow becomes attracted to the high pressured up surface of the wing, creating downforce.

CritiqueAs stated in the introduction to this project, the final work differed from the initial aims that I had set.

However I am glad that this change in direction occurred as having undertaken the research that I have presented in this project I feel that I have gained a far greater understanding of the concept of aerodynamics, and its application to Formula One, than I would have if had continued with my original aims and objectives. The knowledge gained during the course of the project and subsequent look into the application of this research in the design of a front wing, will form an astute grounding in the complex field of aerodynamics, hopefully allowing me to progress this knowledge further, leading me onto to future projects concerned with the subject, particularly looking towards next year’s project where this work will be able to be applied to the design of an aerodynamic component that I wish to undertake.

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ReferencesCFD Front Wing Analysis. F1technical.net. Retrieved from http://www.f1technical.net/forum/viewtopic.php?f=6&t=7384&start=75

Image References:

Figure 2.1. [image online] Available at: <http://www.f1-country.com/f1-engineer/aeorodynamics/aerodynamics.html>

Figure 2.2. [image online] Available at: <http://www.grc.nasa.gov/WWW/k-12/VirtualAero/BottleRocket/airplane/boundlay.html>

Figure 2.3. [image online] Available at: <http://www.brighthubengineering.com/hydraulics-civil-engineering/58434-drag-force-for-fluid-flow-past-an-immersed-object/>

Figure 2.4. [image online] Available at: <http://www.avalanche-center.org/Education/glossary/laminar-flow.php>

Figure 2.5. [image online] Available at: < http://people.oregonstate.edu/~warnersa/research_phd.html>

Figure 2.6. [image online] Available at: < http://www.diracdelta.co.uk/science/source/d/o/downforce/source.html#.UX08u7Xvvm5>

Figure 2.7. [image online] Available at: <http://www.formula1-dictionary.net/coanda_effect.html>

Figure 2.8. [image online] Available at: <http://howthingsfly.si.edu/aerodynamics/pressure-drag>

Figure 2.9. [image online] Available at: <http://www.asracingblog.com/6/post/2012/12/rear-wing-design-1.html>

Figure 4.1. [image online] Available at: <http://www.eng.fea.ru/FEA_news_543.html>

Figure 4.2. [image online] Available at: <http://www.shell.com/global/products-services/motorsport/ferrari/technical-partnership/f1-explained/wing-profiles-rear.html>

Figure 4.3. [image online] Available at: <http://www.racecar-engineering.com/technology-explained/diffusers-engineering-basics-aerodynamics/>

Figure 5.1. [image online] Available at: <http://www.eng.fea.ru/FEA_news_543.html>

Figure 6.1. [image online] Available at: <http://www.formula1-dictionary.net/ground_effect.html>

Figure 6.2. [image online] Available at: <http://scarbsf1.com/blog1/2010/03/11/235/>

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BibliographyHistory of F1. Formula1.com. Retrieved February 15, 2013, from http://www.formula1.com/inside_f1/safety/history_of_f1_safety/7423.html

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Science Behind F1 Aerodynamic Features. F1-country.com. Retrieved February 25, 2013, from http://www.f1-country.com/f1-engineer/aeorodynamics/aerodynamics.html

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Boundary Layer. nasa.gov. Retrieved February 26, 2013, from http://www.grc.nasa.gov/WWW/k-12/airplane/boundlay.html

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Katz, J. (2006). Race Car Aerodynamics. Cambridge: Bentley Publishers

McBeath, S. (2011). Competition Car Aerodynamics. Yeovil: Haynes Publishing

Hill, T. (2011). Formula One: The Complete Story. Hertfordshire: Transatlantic Press

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Word Count: 20,508

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Documents

INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR