formula 1 aerodynamics - front wings (2010)

EML 6934 – Flow Control: Technical Review

Formula 1 Aerodynamics

Instructor: Dr. Louis Cattafesta

Author: Shaurya Verma

UFID: 19151585

Abstract: Aerodynamics has surfaced to be a key factor in the success of a Formula one car. The

overall shape and additional aerodynamic appendages can yield several performance

improvements. This review briefly studies the evolution of the overall shape and aerodynamic

appendages of Formula One cars, describing their functions and shortcomings, while focusing on

the recent developments in front wings and their ancillary surfaces like fins, flow separators and

flaps. Then the paper delves in to the important modifications that were put into effect after the

changes in rules in the last two years. Following that, it also studies the suitability of the different

variations to the wing vis-a-vis their suitability for tracks with disparate downforce and drag

requirements. In the end, it critiques the effectiveness of the rule changes, towards fulfilling their

objectives and suggests alternate methods to achieve the same.

Shaurya Verma ▪ [email protected]

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Contents

Abstract…………………………………………………………………………………………………………………………1

Contents…………………………………………………………………………………………………………………………2

Figures……………………………………………………………………………………………………………………………3

1. Introduction……………………………………………………………………………………………………………………5

2. Formula One Control Surfaces………….………………………………………………………………………………7

2.1. Front wing………….……………………………………………………………………………………………………..8

2.2. Nosecone………….……………………………………………………………………………………………………..13

2.3. Rear Wing………….……………………………………………………………………………………………………15

2.4. Barge Board…….………………………………………………………………………………………………………16

2.5. Diffuser…….……………………………………………………………………………………………………………..17

2.6. Splitter…….………………………………………………………………………………………………………………20

2.7. Wheels…….………………………………………………………………………………………………………………20

2.8. Miscellaneous devices………………………………………………………………………………………………22

2.8.1 Gurney Flaps…….………………………………………………………………………………………………22

2.8.2 Sharkfin…….…………………………………………………………………………………………………..…23

2.8.3 Winglets and miscellaneous control surfaces………………………………………………..……24

3. Trackwise distinction and variation…………………………………………………………………………..……28

4. Rules and limitations…………………………………………………………………………..…………………………30

4.1 Variations of rules – cause and effects………………………………………..……………………………..30

4.2 Latest Rules and Regulations………………………………………..…………………………………………..30

4.3 Alternative solutions………………………………………..………………………………………………………32

5. Conclusions and Future work………………………………………..………………………………………………..33

References………………………………………..…………………………………………………………………………...34


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Figures

Fig. 1: Alfa Romeo 159 – The championship winning Formula One car (1951)

Fig. 2: Fig 2: The Chaparral 2E with a high mounted rear wing

Fig 3: Dual element front wing with end plates of a Minardi M195 (1995)

Fig 4: Lotus 49B: the first F1 car with a front wing (1968)

Fig 5: A multi element front wing of the McLaren MP4-22 (2007)

Fig 6: [Left] F1 endplates creating an inwash and an outwash.

Fig 6: [Right] Functioning of a front wing.

Fig 7: [Left] A complex inwash based end plate on the McLaren MP4-21 (2006)

Fig 7: [Right] An outwash based arrangement on the Brawn BGP001 (2009)

Fig. 8: The ‘walrus nose’ of the Williams FW26 (2004)

Fig. 9: A saw-tooth Gurney flap on the front wing of the Ferrari F2004 (2004)

Fig. 10: Vertical fences below the main plate of the front wing of the Red Bull RB4 (2008)

Fig. 11: Important changes to the rules related to the front wing from 2008 to 2009

Fig. 12: The endplate on the front wing of the Ferrari F60 (2009)

Fig. 13: The endplate on the front wing of the Force India VJM02 (2009)

Fig. 14: Important changes to the rules related to the front wing from 2008 to 2009

Fig 15: (LEFT) The low nosed Williams FW15C (champion 1993)

Fig 16: (RIGHT) The high nosed Benetton B195 (champion – 1995)

Fig 16: [Left] Vented nose in the Ferrari F2008 (2008)

Fig 16: [Right] a delta winglets on a Red Bull RB4 (2008)

Fig 17: Comparison of a low downforce rear wing (Monza) and a high downforce rear wing

(Monaco) on the Toyota Racing F1 car

Fig 18: The function of the end plates of rear wings


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Fig 19: Bargeboards and turning vanes on a Formula one car.

Fig 20: Inverted airfoil bottom and skirts on the Lotus T79

Fig 21: [Left] The Brabham BT46B (1978) with a suction fan

Fig 21: [Right] The Chaparral 2J (1970) with a suction fan

Fig 22: [Left] Formula one car diffuser with air flowing outwards and upwards (Schematic)

Fig 22: [Right] The diffuser of the Ferrari F430 production car

Fig 23: The splitter of a Mercedes W01 (2010)

Fig 24: Visualization of the vortices shedding from an isolated rotating wheel

Fig 25: The effect of a Gurney Flap

Fig 26: Comparison of A McLaren MP4-23 with and without a sharkfin (2008)

Fig 27: Sidepod panels on Formula One cars

Fig 28: Additional winglets on the side of the side pod of the McLaren MP4-21

Fig 29: The Tyrell X-wing (1997)

Fig 30: The Honda ‘dumbo’ wings on the RA108

Fig 31: The centreline downwash generating (CDG) wing (schematic)

Fig 32: Wake characteristics of the CDG (simulation)

Fig 33: Air vents, louvers, chimneys and gills on Formula One cars

Fig 34: BMW antlers and horns (2008)

Fig 35: A second front wing on a McLaren M26 (1978)

Fig 36: The Mclaren snowplow (2009)

Fig 37: Track layouts of Monza and Monte Carlo

Fig 38: The front view of the cars in 2008 and 2009 (schematic)

Fig 39: The top and side views of the cars in 2008 and 2009 (schematic)

Fig 40: Rear view of the cars in 2008 and 2009 (schematic)


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1. Introduction

A race car’s performance is a function of its engine, chassis, wheels and aerodynamics. Owing to the

fact that tires are often the same and that the engines are also standardized in many important

racing classes the car’s success boils down to the chassis and the aerodynamics. This paper focuses

on the latter. Obtaining ‘good aerodynamics’ is basically an interplay of two factors: minimizing the

effect of the resistive forces of fluid friction (drag) on the vehicle so as to reach the highest possible

straight-line speeds, and maximizing negative lift (downforce) to keep the moving vehicle stuck to

the ground with the highest possible force. High downforce helps attain higher speeds around

corners without loss traction (due to centrifugal forces), and at the same time, provides additional

stability and reduces braking distances [48]. An aerodynamicist’s aim is to devise an optimum

tradeoff between downforce and drag, in order to attain the fastest laptime.

Now, in a race situation, where the fastest to the slowest of a bunch of around twenty cars may be

separated by two seconds per lap, just a small difference in the optimization of the airflow can make

a huge difference in the result. This is why teams often invest up to 20% of their budgets towards

aerodynamics.2

Testimony to the effectiveness of aerodynamics is the fact that modern Formula one cars can

withstand a lateral acceleration of upwards of 5 g[22], that is, at certain speeds the wheels will not

lose traction despite being pushed outwards by centrifugal forces over five times their own weight.

This figure is considerably higher (approximately four times greater) than what the formula one

cars in the sixties, or even the fastest production cars today can withstand [44], mainly because of

the downforce Formula One cars are designed to produce.

Additionally nuances learnt about aerodynamics while designing Formula One cars repeatedly

trickles down to production cars and at times aircraft as well, thus benefitting more than just the

sport.


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History of Aerodynamics in Car Racing

While developing the first racing cars, the accent was on

achieving the highest straightline speeds. Minimizing drag,

was quickly identified as contributive to the same, and this

led to ground breaking designs of the era, like Rumpler’s

Tropfenwagen (German for “droplet shaped”) developed

in 1924 which looked like a symmetrical airfoil from the

top and had a coefficient of drag of 0.28[3]. To put that into

perspective, the Ferrari F430 sports car has a CD of 0.34[4].

Although, just about four years after that wings set at a negative angle of attack were employed in

Opel’s rocket powered RAK1 and RAK2, harvesting the potential of downforce was not discovered

till the ‘60s[5]. Even the vastly successful Alfa Romeo 159 that won the championship in 1951 was

just optimized to minimize drag. (Fig. 1)

The first major foray into successfully translating downforce into performance was in 1956, when

Michael May mounted an inverted wing atop the cockpit of his Porsche 550 Spyder. This was,

however, soon banned because it obscured the vision of the following drivers[7]. Ten years later,

Chaparral installed a high set rear wing on Chevrolet-Chaparral 2E and soon, most of his

competitors followed suit [45]. (Fig 2)

Fig 2: The Chaparral 2E with a high mounted rear wing, raced in the CanAm series

Fig 1: Alfa Romeo 159 formula 1 car designed to reduce drag (1951)


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Soon front and rear wings became permanent fixtures on cars and teams started recognizing the

importance of downforce, and despite intermittent reduction in engine power, average speeds over

circuits continued to increase.

On a side note, the reason of Ferrari F430, has a higher coefficient of drag than a car launched

eighty years before it, is because the F430 is built to generate downforce, at the expense of drag.

Additionally, it has a smaller frontal area, so despite the lower CD, it experiences lesser drag.

2. Control Surfaces on Formula One Cars

2.1. The Front Wing

The front wing, in its most simplistic form, is a low aspect ratio inverted airfoil suspended from the

front of the nose cone of the car to provide downforce and improve its aerodynamic characteristics.

Since it is generally the first element of the car encountered by the oncoming flow, it is also

responsible for reducing drag by smoothing the oncoming air and channeling it to other control

surfaces to improve their functioning, or to help cool them. (Fig 3)

Fig 3: Dual element front wing with end plates of a Minardi M195 (1995)[23 – Section 3]

While the first front wing, introduced by Lotus in 1968 was just a rectangular airfoil (Fig 4)[23 – Sec. 2],

today’s front wings are much more complex contraptions (Fig 4). After the introduction of multi

element front wings by McLaren in 1984[5 – Sec. 5.2], almost all front wings have at least two main

elements. Owing to limitations imposed by the FIA regulations and the effect of the proximity of the

front wheels the wings are neither flat, nor with a constant chord length.


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Fig 5: A multi element front wing of the McLaren MP4-22 (2007). Notice - three wings in the main profile and an additional bridge wing on top.[24]

Typically, the front wing generates around 25-30% of the total downforce created by the car.

However, while following another vehicle from a distance of less than twenty metres[32], the

turbulent wake of the leading car causes this to fall by around thirty percent. This loss of downforce

Fig 4: Lotus 49B: the first F1 car with a front wing (1968) [5 -Sec. 5.3].

and thus, the maximum available traction while following a car makes it harder for the pursuing car

to overtake in fast corners, where performance is mainly a function of downforce. Around slower

corners, downforce does not play a key role, and just the mechanical grip (Section 3) is decisive. On

straights, on the contrary, downforce is high, but it is not the limiting agent for speed. Straight-line

speed is largely a function of drag, and the same wake translates into a reduction in drag, thus

boosting the speed. Utilizing the wake of another car is called drafting or slipstreaming[49].

The modern front wing is generally composed of a two or more elements either in a single profile,

that is with the second airfoil very close to the trailing edge, and may also have different airfoils

parallel to each other forming a structure similar to a bi-plane. The front wing of the McLaren MP4-

22 consisted of both multi element wings oriented one after another, and also a bridge plane

running above the tip of the nosecone. (see Figure 4)

Another major update was seen in the late nineties, when teams began using flexible front and rear

wings that bent and reduced its angle of attack at high speeds, causing reduced drag on straights

without the penalty on downforce around corners. This caused a drastic upsurge in the apex speeds

possible. But, after the Johnny Herbert’s crash in Barcelona in 1999 [34], which was caused by the


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collapse of the flexible rear wing of his Stewart-Ford, the FIA imposed a restriction on the maximum

allowable wing deflection for a given load, which is still applicable.

Endplates: Owing to the low aspect ratio of the front wing, it is highly prone to the influence of

wing-tip vortices and thus, induced drag. So, endplates are attached to the wingtips to curtail the

formation of undesirable vortices at both ends of the wings. More importantly, the end plates also

serve the purpose of directing the airflow away from the front wheels. Thus they are shaped like

airfoils. They either push the flow outwards, creating an outwash, or inwards, creating an ‘inwash’.

Before 2009, when the front wing was considerably narrower than the wheels, the latter was more

popular, however, after the rule changes, the former is more practical. (See section 4)

Fig 6: [Left] A diagram showing the endplates creating an inwash and an outwash[19]

. [Right] An explanation of the functioning of a front wing

[20].

An upper flap (or multiple upper flaps) is also often seen on the front wing, running parallel to and

above the main plane, from the end plate to around half the distance to the mid-point. The function

of thus auxiliary wing is primarily to condition the flow around the wheel, and thus to help reduce

the deleterious vortices induced by the wheel.

Fig 7[24]

: [Left] A complex inwash based end plate arrangement on the McLaren MP4-21 (2006) and [Right] an outwash based arrangement on the Brawn BGP001 (2009)


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Fig. 8: Williams FW26 (2004)[24] [Photo:24]

Walrus nose: Williams designed a shorter nosecone

with tusk shaped vertical spars extending forwards

to connect to the front wing. This was done in order

to increase the airflow towards the underbody, in

order to increase downforce.[26] The new nose was,

however over-sensitive to cross-winds and was

largely unsuccessful.

The second notable element is the bottom edge outside the end-plate, which is designed as a

venturi channel to create a low pressure zone beneath it.[24]

Fig. 9: Ferrari F2004 (2004) [24] [Photo:24]

A saw tooth gurney flap at the trailing edge of the

front wing gives the additional downforce of a

Gurney flap (See section 2.8.1), with less of its drag

penalty.[24]


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Fig. 10: Red Bull RB4 (2008) [24] [Photo:24]

Major changes shown here were for Silverstone,

which is a fast circuit.

1. Vertical fences beneath the main wing to

better manage the airflow underneath and

curtail large vortices from passing.

2. The wing was made wider, with the end-

plates extending further outwards.

After a revamp of the FIA regulations for the season 2009, the front wing changed considerably. The

following is a diagram explaining the changes in the rules related to the front wing.[24][Photo:24]

Fig. 11: Important Changes from 2008

to 2009

The front wing was made lower and

wider, thus increasing the downforce

available at the front.

A universal central section was

established, that all teams would comply

with.

Additionally, the flap section was made adjustable by the driver up to twice a lap over a range of six

degrees.[24] [Photo:24]


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Fig. 12: Ferrari F60 (2009) [24] [Photo:24]

1. Ferrari introduced a second endplate to better

manage the flow around the tyres, by helping it

flow outwards.

2. A small fin, which is a non-inverted airfoil, was

included.

3. An additional slot to support the upper deck of

the wing was introduced. Theoretically it was to

avoid the creation of a vortex while working in conjunction with the planes and the end

plate.

Fig. 13: Force India VJM02 (2009) [24] [Photo:24]

Force India’s solution for Spa, a relatively fast

circuit contained a vertical bridge close to the nose,

here seen towards the right. This was to reduce

transverse flow on the wing’s main plane and to

improve the flow going towards the underbody.

The end plate consisted of three elements, again to

aid in the outwash.

Fig. 14: Changes from 2009 to 2010[24]

[Photo:24]:

While the rules for the front wing remained

unchanged, the front tyre width was

reduced, and the rear bodywork was made

longer, in order to accommodate the larger

fuel tanks after refueling was banned.


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2.2 Nosecone

The early Formula One cars were all front engined [36] (till around 1961) and the front of the car

was used to house the engine radiators [9] and with little the emphasis that was laid on

aerodynamics at that time, it was large and fairly buff, designed mainly with an accent on visual

appeal (see Fig 1). Gradually, as engine displacements had restrictions imposed on them, and as

aerodynamics began to be appreciated better, the nose became more streamlined. The introduction

of rear engined cars around 1960-61 caused a further reduction the dimensions of the nose. In

1970, the revolutionary Lotus 72 introduced hip mounted radiators[25] and the function of the nose

was reduced to improving the airflow around the rest of the car. By this time the efficacy of

downforce in improving performance was well known and all noses were low with the front wing

integrated in them (Fig 3).

Fig 15: (LEFT) The low nosed Williams FW15C (champion 1993) and (RIGHT) the high nosed Benetton B195

(champion – 1995)

Although minor developments in the nose contour kept on occurring in the nose, making it more

streamlined, the next major breakthrough was in 1990 when Tyrell introduced the high nosed

Tyrell 19[5 – Sec. 5.2]. The tip of the nosecone of this car was above the plane of the front wing. While its

uninspiring performance created little excitement about the design’s efficiency, slight

improvements in suspension components and better implementation of the idea made it clear that

this was the superior design. The reason a low nose was rejected in favor its successor, was that

although the downforce achieved by more horizontal snout in isolation was admittedly lower, it

helped guide a greater volume of air underneath the car and into the diffuser, boosting the ground


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effect (see section 2.5) and thus causing an overall increase in the downforce of the car. The

reduction in drag by the new shape was immediately evident. Additionally, since the nose did not

bisect the front wing, a larger area was available, again helping with downforce. The slight tradeoff

of the high nose was the driver’s visibility. The last low nosed car to win the driver’s or

constructor’s championship was the Williams FW15 in 1993 (Fig. 15) and by 1997 all Formula One

cars had high noses.

Till today, all cars run a high nose design, while some may be lower and closer to the front wing;

they are all connected to a full front wing by airfoil shaped spars. The sides of the nose are shaped

so as to direct the flow into the sidepods, and the top acts as a small aid in providing downforce.

All noseboxes are made of lightweight carbon fibre impregnated with resin and attached to the

monocoque. It also functions as an energy absorbing cushion in case of impact and disintegrates

into small fragments upon colliding, thus damping the blow. [9]

Often, the nose also has an additional protuberance to accommodate the front camera. It may have

extra winglets like delta-wings attached to it, and may have vents to increase downforce (Fig. 7).

The nose may have a snow plow beneath to clean and accelerate the underbody flow.

Fig 16: [Left] Vented nose in the Ferrari F2008 (2008) [Right] a delta winglets on a Red Bull RB4 (2008)


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2.3 Rear Wing

The rear wing is primarily a downforce generating device attached to the car’s rear end, above the

diffuser, extending laterally between the two wheels. Working symbiotically with the diffuser, it

generally contributes about 30 to 40% of the total negative lift created by the car.

Fig 17: The Toyota Racing F1 car with a low downforce rear wing for Monza (left) and a high downforce setup for

Monaco

Unlike the front wing, the rear wing has greater leeway for variation to suit circuit requirements.

This is because, while front wing has to conform to the contours suiting the shape of the body to

maintain a smooth airflow throughout, the rear wing has fewer restrictions to be flush with the

aerodynamics of the body. Its effect is more prominent downstream, where larger variations are

tolerable. This is why; on a slow circuit like Monaco the rear wing can be inclined at a very high

angle of attack whereas at a fast circuit like Monza

it is much less steep (Fig 17). This is, however, a

rule of the thumb and different configurations can

be used to custom match the circuit characteristics

(see section 3).

The wing is attached to the car by endplates,

which, in addition to supporting the wing, also aid

in checking induced drag, which is caused by air leaking out of the wingtips from the high pressure

Fig 18: Illustrating the function of the end plates of rear wings by Shell.com


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upper surface outwards and downwards to the low pressure lower surface thus causing trailing

vortices and drag, accompanied by a fall in the total lift. Since the wings are low aspect ratio, the

potential effect of induced drag is more prominent, and thus, the endplates, all the more

essential.(Fig 18)

2.4 Bargeboards

Bargeboards are aerodynamic devices that look like skirts (curved vertical planes) attached to the

vehicle in front of the lower surface of the sidepod inlets and behind the front wheels that curve

along with the contour of the body. Bargeboards were initially invented to [12] shield the radiator

duct from the recirculating wake of the front wheels and to direct the turbulent flow laterally

outwards so that only clean air entered the radiator and the underbody of the car. Later, teeth were

incorporated in the lower surface of the bargeboards so as to shed vortices that energized the

airflow underneath the car to be favorably turbulent to stay attached to the diffuser longer, and

thus, increase downforce.

Fig 19: A schematic diagram of bargeboards (both shades of red) and turning vanes (orange) on a Formula one

car.

Bargeboards may be assisted by smaller similar looking ancillary structures placed upstream of

them, with smaller curvature, called turning vanes.(Fig. 10)


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2.5 Diffuser and the floor

The floor of the car is the flat (or stepped) part of its underbody where most of the downforce is

obtained. Here, the negative life is obtained by virtue of the ground effect. To understand ground

effect, the volume of air between the floor and the ground needs to be visualized as a duct. One can

observe how it is analogous to a venturi tube. That is, as a large volume of air that passes below the

nose, is directed towards the underbody by the splitter, it increases in speed due to the reduction in

area, consequently creating a low pressure zone underneath it, and therefore, downforce. The

effectiveness of this phenomenon was exploited best by Lotus in 1978 when they shaped the

bottom of the sidepods and the radiators to look like an inverted airfoil, thus magnifying the effect

(fig 20).

Fig 20: [Left] The Lotus T79 with the inverted airfoil bottom and skirts (1978) [Right] Schematic diagram of the

same showing the underbody shaped like an inverted wing.

To keep the low pressure area sealed from the relatively higher pressure air outside, the lateral

extremities were extended downwards to resemble a ‘body end-plate’ also known as the ‘skirt’. It’s

shape led to the colloquial appellation of arrangement as a ‘side wing’ or ‘under wing’[33].

Technically the nomenclature was deemed as inaccurate as the effect of the wing was only


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noticeable due to its proximity to the ground and if the wing were inserted in free flow, very little

downforce would be created.

The same year, Brabham responded to Lotus’s excellent implementation of ground effect in its

BT46B by making what was commonly dubbed as the ‘fan car’. Reminiscent of the Chaparral 2J

developed for the Can Am series over seven years ago, Brabham installed a propeller at the rear end

of the car which extracted air from its floor and pushed it backwards, again creating a low pressure

area beneath the car.[5][33] The advantage in this case was that a high amount of downforce was

created even at lower speeds, and the exact amount of it could be regulated based on its need. The

tradeoffs were the additional expenditure of engine power and the increase in weight and

complexity. The car won its debut grand prix and much like the Chaparral’s fan which was banned

soon after its implementation, the governing body declared this concept illegal as well after its

maiden race. (Fig 21)

Fig 21: [Left] The Brabham BT46B (1978) driven in Formula 1 and [Right] The Chaparral 2J (1970) driven in the

Can Am Series [48]

In 1983, Formula 1 regulations were modified to require flat underbodies and no skirts and further

modifications in 1994 introduced a central step running throughout the length of the underbody.

However, flow acceleration could still be achieved under the body.[5][33]

It is important to note that the effectiveness of ground effect is also a function of the ground

clearance. If the floor height is very low, boundary layer extends throughout the volume inhibiting

any airflow beneath the vehicle, hence, resulting in undesirable positive lift. With increasing


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clearance, better high speed airflow is attained thus creating downforce reaching a maximum

around 55mm and then the downforce begins to fall as leakage increases and the venturi effect gets

less pronounced.

Now, for an F1 car, within restrictions, in order to better tap the power of the flow beneath the car,

proper inlet and outlet are required. The inlet is the chin, beginning from the splitter and the lower

edge of the radiator inlets that gathers the flow beneath the nose and smoothly directs it below the

vehicle. The outlet, called the diffuser, which is the most critical part of the flow; is shaped like an

upsweeping rear end of the vehicle and has the sole purpose of driving the high speed air across an

adverse pressure gradient along an increasing area without separation. (see figure 22)

Fig 22: [Left] An artist's rendition of a formula one car diffuser with air flowing outwards and upwards[28]. [Right]

The diffuser of the Ferrari F430 production car installed for the same purpose[34].

This is achieved with the help of the Coanda Effect around the sidepods,[33] which is accomplished

by designing the rear of the car as a tapering contour (the proverbial ‘coke-bottle’ shape) which

guides the air flowing through the flanks (aero) to accelerate and thus become low pressured,

which helps in sucking the air upwards from the diffuser and helps prevent separation. The rear

wing and its secondary surfaces also create a low pressure area just above and downstream of the

rising flow, again preventing flow separation. Typically the floor and diffuser contribute about 35-

40 percent of the total downforce.


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2.6 Splitter

The splitter is predominantly a flat surface which divides the oncoming flow smoothly into a part

that is supposed to flow beside or above the vehicle and a second part that is directed to flow at

high speed below the vehicle. It is designed to improve the aerodynamic efficiency of the flow

(mainly) below the car [13]. Its height is generally the same as the floor height and longitudinally it is

slightly ahead of the bargeboards, which it often supports. (see figure 23)

Owing to its low height and central location, a splitter is the prime choice for ballast.

Fig 23: The splitter of a Mercedes W01 (2010) [Left] from the side and [right] from the front[13].

2.7 Wheels

The wheels (including the tyres) are the only connection of a car and all its gadgetry and the earth.

While there are other very important functions of a wheel, this paper shall only focus on the

aerodynamic implications.

In Formula one, the rules forbid the wheels to be covered. This is highly detrimental to achieving an

aerodynamically efficient body. Not only do wheels cause excess drag that a streamlined cover may

have prevented, their forward rotation while rolling induces positive lift and vortices which are

undesirable for performance. Although, it is a documented fact that rolling wheels produce less

drag than stationary ones (Fackrell 1974) they also produce lift. This is because, at the lower part of


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the leading side, the flow separates and is at a high pressure. Also, a rotating wheel, in presence of

the ground, originates a system of three pairs of counter rotating longitudinal vortices in the wake

(Cogotti (1983) and Mercker et al. (1992)) (Fig. 1). A pair of them sheds from the top, a second from

the wheel axis and the third from the bottom, attached to the ground. This last pair of higher

intensity is called “jetting” vortices (Morelli, 2000).[14]

Fig 24: Visualization of the longitudinal structures around an isolated rotating wheel with the six vortices

shedding from it . (Mercker & Bernerburg, 1992)[36]

Although one of the functions of the front wing is to scoop away as much airflow from the front tire

as possible, and direct it, without disturbance towards the underbody and the radiators, it is not

always possible to draw an adequate amount of air away. This is particularly pronounced while

turning, when the wheels are not symmetrical and create a transverse aerodynamic force and

unbalanced moments. While this provides a minor advantage if the car has a tendency to

understeer undesirably, in most cases, an unbalanced moment only unsettles the vehicle.


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2.8 Miscellaneous Devices

2.8.1 Gurney Flaps [37] [15] [38]

A Gurney Flap (also known as wickerbill) is a small,

generally flat tab, approximately perpendicular to

the chord that projects towards the high pressure

side (for most cases) of the trailing edge of the

airfoil. It is generally around 2% of the chord length

that is around the size of the boundary layer and

can considerably improve the performance of the

airfoil. [38]

The Gurney flap generates additional (negative) lift

on the airfoil by altering the Kutta condition on the

trailing edge thus allowing the stagnation point to

lie away from the trailing edge. It creates a low

pressure area behind it helping suck the air from

the cambered side and delay separation, and at the same time, increases the pressure in the

concave area upstream of it, consequently increasing downforce.

In view of the fact that Formula One airfoils are thin, the Gurney flap is also accompanied by a drag

penalty, which is not the case for bulbous airfoils. Besides, Gurney flaps create spanwise counter-

rotating vortices that are alternately shed in a von-Karman vortex sheet, so slight modifications in

the wing profile are often preferred to using a gurney flap on the main wing. However, they can

often be seen on smaller winglets, endplates and at times, even the rear wing. [24]

Fig 25: The Gurney flap helps keep a flow that would separate otherwise attached.

[15]


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2.8.2 Shark Fin

First implemented in Formula One in 2008 by McLaren, the shark fin is a ridge-like extension of the

engine cover airbox extending backwards, towards the mid-point of the rear wing. It provides a

barrier between the flows from the two sides from mixing, thus curtailing the shedding of vortices

and aiding the effectiveness of the rear wing.

Fig 26: [top] A McLaren MP4-23 without a sharkfin (2008) & [bottom] McLaren MP4-23 (later in 2008) with one.

However, owing to its large profile area, it makes the car more sensitive to cross winds, resulting

additional yaw instability.

F-Duct:[39] The shark fin also forms a part of the F-Duct, which is a radical new idea that was first

designed by the McLaren Racing team in 2010. Rules banned any moveable aerodynamic surfaces,

so McLaren used the driver’s body as a moveable surface (with respect to the chassis). The chassis

had a duct which the driver’s knee could block on the straights, when additional downforce was not

required. Once blocked, the air was directed through the shark-fin via the top of the engine cover,

and blown into the slot of the rear wing elements, reducing downforce, but more importantly, drag.

This system was later emulated by other teams including Ferrari and Mercedes.


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2.8 Winglets and Miscellaneous Control Surfaces

A winglet is a rough term for all the extra plates and airfoils attached to the car to serve the same

purpose as the main wings – add downforce, and/or smooth and condition airflow. Extra winglets

and fins are generally attached ahead of the sidepods, on top of the sidepods, on the front of the

monocoque, and ahead of the rear wings, depending on the Formula One rules at the given time. A

few notable ones are given below.

SIDEPOD PANELS

Fig 27: Side pod panels to direct flow around the mid and the rear of the car more efficiently. As can be seen in the leftmost and the rightmost photos, they were also used to support the rear view mirrors. [left to right] Ferrari F60 (2009) Mercedes

GP W01 (2010), Red Bull RB6 (2010), Force India VJM03 (2010).

SIDE POD WINGLETS

Fig 28: Additional winglets on the side of the side pod of the McLaren MP4-21 (2006) designed to increase downforce and smooth out the wind - rear wing interactions.

[32]


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OLDER X WINGS

Fig 29: Tyrell X-wing (mid wings) in 1997 at Monte Carlo, designed to increase the availabe downforce.[40]

DUMBO WINGS

Fig 30: Honda ‘dumbo’ wings on the nose cone of the RA108 (2008). The car met limited success, but that was due to inefficiency of the rest of the package caused by a miscalibration of the Honda wind tunnel.

[40]


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CDG WING

Fig 31: The centreline downwash generating (CDG) wing proposed as a potential solution to improve overtaking by improving the characteristics of the flow in the wake.

[27]

Fig 32: Simulation results of the CDG show lesser upflow, reducing the downforce of a car in the wake.[27]

Fig 33: Air vents, louvers, chimneys and gills on Formula One cars, usually located on the sidepods and radiators.[21]


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RECENT MID WINGS AND ANTLERS

Fig 34: BMW antlers and horns - functioning as secondary front wings and mid wings respectively. (2008) [40]

SECOND FRONT WINGS

Fig 35: A McLaren M26 in practice in Spain (1978) testing a second front wing. [40]

McLAREN SNOW PLOUGH

Fig 36: The snow plough is a chiseled horizontal surface installed beneath the nose that acts like a diffuser mounted higher above the ground. On the upper surface, it splits the flow to go either towards the left of the right

while the flow below it is expanded and thus at a low pressure.


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3. Track Wise Aerodynamic Variation.

The aerodynamic requirements for a fast laptime vary considerably with the conditions of the track.

The exact number and length of turns (curves), speed at the curves, length of the straights, relative

position of straights with respect to slow/fast turns, relief and banking of the track all decide the lift

v/s drag ratio that would optimize the laptime. In addition to lift/drag, it is also important to study

the moments, points of high downforce on the car and its overall balance. Aerodynamic surfaces

may be added or removed for the same to suit the different conditions.

While a slow twisty circuit like Monte Carlo (Monaco) would require greater focus on negotiating

the myriad corners fast, and thus on achieving high downforce, a fast circuit like Monza, would

necessitate keeping the drag as low as possible, so as to exploit the long straights to achieve high

average speeds.

Fig 37: [Left] Monza: the fastest circuit and [Right] Monte Carlo: the slowest circuit on the

calendar (2010)[41][42]

Nonetheless, even on medium-fast circuits, downforce can be important. In case the turns are fast

and long, speed at the turns can become the primary concern, which as explained above, is

determined by the downforce levels. Thus they may require a high downforce setup.

On the same circuit, a car that is running with a high downforce setting will be faster around

corners than a low downforce car, given the same mechanical settings, but it will lose out to the

latter on the apex speed on a long straight. However, for turns with a very low curvature, that can

be administered almost flat out (with full throttle), even faster ones, more than the requisite

downforce may be available, in such cases, again, the latter will be faster.


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Here, it is also appropriate to talk about grip, which is also a function of the car suspension and

tyres. Grip is generally divided in to two parts: mechanical grip and aerodynamic grip. Mechanical

grip is traction obtained by the car without any effect of fluid flowing around it. It depends on mass

repartition, tyre contact area, tyre temperature, rubber adhesiveness, camber angle, and

suspension stiffness.[46] Aerodynamic grip, on the other hand is the additional grip obtained due to

downforce. While all grip is limited by the tires, downforce helps increase tyre ground adhesion.

Now, as downforce roughly increases with the square of speed, the aerodynamic grip is much more

noticeable at higher speeds, as a rule of the thumb, at greater than 60mph. Consequently, the speed

at hairpins is largely determined by the car’s mechanical grip, while the speed at spoon curves or S-

curves by aerodynamic grip.

The following is a list of the circuits used in Formula One racing in the seasons 2009 and 2010. [24]

Name Distance Time

Avg. Speed (Km/h)

Avg.Speed (Mph)

MONZA 5.793 81 257.47 159.98

SPA-BELGIUM 7.004 105.1 239.91 149.07

SILVERSTONE 5.141 78.7 235.17 146.13

SUZUKA 5.807 91 229.73 142.75

MELBOURNE 5.303 84.125 226.93 141.01

TURKISH 5.338 84.77 226.69 140.86

GERMANY 4.574 73.8 223.12 138.64

INTERLAGOS 4.309 71.5 216.96 134.81

BAHRAIN 5.412 90.25 215.88 134.14

CANADA 4.361 73.6 213.31 132.54

CHINA 5.451 92 213.30 132.54

MALAYSIAN 5.543 94 212.29 131.91

FRANCE 4.411 75.3 210.88 131.04

BARCELONA 4.655 81.67 205.19 127.50

HUNGARY 4.381 79.1 199.39 123.89

ABU DHABI 5.554 100.3 199.35 123.87

VALENCIA 5.44 98.7 198.42 123.29

SINGAPORE 5.067 105.6 172.74 107.33

MONACO 3.34 74.4 161.61 100.42

As explained above, cars run a high downforce setting on medium-fast to slow tracks, and a low

downforce setting on fast tracks. Note: the average speeds have been obtained from the best lap

Fast T

racks M

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m Sp

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racks Slo

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racks


30 | P a g e

figures, which depend on the rules at the time the circuits were raced on, and are thus only

indicative of its average speed.

4. Modifications in Technical Regulations

4.1 Objectives of the Modifications

Formula One technical rules and regulations are constantly updated by the sport’s governing body,

the FIA (Fédération Internationale de l’Automobile), either to seal loopholes that were not

identified earlier and led to the development of parts that were deemed unsafe or anti-competitive

or to enhance the racing and viewer experience and consequently improve the sport’s appeal,

safety, marketability, following and profit. Often sustainability of the sport and reducing the

negative ecological impact are also stated as reasons. Since rule changes cause cessation of product

development cycles, major rule modifications are rarely enforced.

This paper will only discuss the important aerodynamic changes implemented at the end of 2008,

when a host of major modifications were introduced.

The major goals stated were:

1. To control costs, thus allowing more private constructors to race.

2. To reduce the effect of the wake and facilitate overtaking

3. To develop ecological solutions of practical relevance to the world (implementation of

KERS)

4.2 Major Modifications

Final Result of the Changes[16][17][18]

1. The front wing span was increased from 1400mm to 1800mm to as to reach the extremities

of the tyres.

2. The front wing was moved forward, and turning vanes between the wheels were banned

3. Bridge wings (or full span double wings) were banned, while, half-width upper plans were

still allowed.


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4. Nose cone: boomerang/ear/vikings wings were banned.

Fig 38: Simulation of the front view of the cars in 2008 and 2009. Control surfaces are highlighted in blue [16]

5. Winglets, cooling apertures, extensions, shark gills, between the wheels, apart from were

banned.

6. Bargeboard dimensions were reduced.

Fig 39: [top] The cars as seen from above, [middle] relative profiles of the cars [16]


32 | P a g e

7. The rear wing was made higher (950mm) and narrower (750mm)

Fig 40: Rear view [16]

4.3. Alternative Solutions

Improving the visual spectacle of races by increasing overtaking was one of the main objectives of

the rule changes. The rules have further been tweaked for 2011. The new rules allow the driver to

adjust the rear wing while following another driver. This is expected to find application on

straights, where it’ll allow better exploitation of the wake.

Another alternative that could possibly work is a slight modification of the proposed mechanism to

aid overtaking around corners. It is based on including a third high downforce setting. If the same

system is allowed to increase wing angles (even the front wing) when within a certain distance of

the leading car, high downforce would be available even around corners. The system could be

manual or automatic, employing an aerodynamic mapping such that the system automatically

detects the optimum angle based on the location on the circuit, employing two-way telemetry as

used for engine mapping, before it was banned in 2003.

Apart from aerodynamics, the circuit layout is also a critical factor in facilitating overtaking, as

explained by Clive Bowen (Apex Circuit Design)[43]. The major possible ways of improving

overtaking, in addition to reducing downforce are:

1. By increasing the margin for error on corners by providing run-off areas, so that there isn’t

a very high penalty for committing a mistake, drivers are encouraged to be more aggressive.

2. Having multiple racing lines through a corner with the same entry to exit time will clearly

make it easier to be fast without having to be exactly in line with the leading car.


33 | P a g e

3. Corner sequencing is also proposed to be an alternative. This proposes a system of corners

where the perfect line through one corner spoils entry line through the next, thus the effort

of defending one’s position successfully at one corner endangers good defense at the next.

4. Another counter-intuitive alternative proposed is based on boosting driver confidence by

increasing the available grip, as opposed to the philosophy of aiming towards reducing grip

by reducing downforce. While the latter hinges on increasing the probability of causing a

driver error, the new theory is contingent on allowing greater room for error that would

encourage drivers to take more risks. The theory proposes banking corners to accomplish

the same. An analysis of the two theories is beyond the scope of the paper.

5. Conclusion and Future Work

Formula One cars have evolved over the last sixty years from being cigar-shaped front engined

vehicles to machines with more in common with airplanes than cars. While developments have

occurred in other aspects of race car development also, the study of car aerodynamics has shot up

from being faintly understood intuition based art to an expansive scientific discourse. The

understanding of downforce and its effect on traction and performance led to a major change in the

pursuit of achieving the fastest laptime. However, due to complex fluid effects like formation of

vortices, shear layers, boundary layer transition etc. the flow is not completely understood yet and

a myriad modifications for improvement are still possible. The paper studied the major

development over the ages, with focus on the latest innovations and probed further into the

evolution of front wings.

Since little is known about the exact airfoils used in racing, the study was mainly qualitative, based

on the data made publicly available. The other aerodynamic surfaces, like the rear wing,

bargeboards could also be studied more comprehensively. A comparative discourse of the

approaches of the different constructors could also be conducted.


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References

[1] http://www.f1technical.net/features/3893

[2] http://www.formula1.com/inside_f1/understanding_the_sport/5281.html

[3] http://en.wikipedia.org/wiki/Rumpler_Tropfenwagen

[4] http://en.wikipedia.org/wiki/Automobile_drag_coefficient

[5] Racecar Aerodynamics – Gregor Seljak (April 2008)

[6] Aerodynamics of Race Cars – Joseph Katz, San Diego State University, San Diego, California.

[7] Explanation and Discovery in Aerodynamics – Gordon McGabe (December 2005)

[8]http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained/

wing_profiles_rear/ (rear wing with or without endplates)

[9] http://f1-dictionary.110mb.com/nose_cone.html

[10] http://en.wikipedia.org/wiki/1970_Formula_One_season

[11] http://www.atlasf1.com/2000/feb16/gray.html

[12] http://f1-dictionary.110mb.com/start_page.html

[13] http://formula1techandart.wordpress.com/?s=splitter

[14] Turbulent Wake behind a Single Element Wing in Ground Effect - Xin Zhang and Jonathan

Zerihan, University of Southampton

[15] http://insideracingtechnology.com/tech104gurney.htm Paul Harney

[16] http://www.f1technical.net/articles/11878?sid=02ad3ff803ccc230adc4eb92e091f955

[17] http://www.f1technical.net/forum/viewtopic.php?f=1&t=5669

[18] http://www.fia.com/en-

GB/sport/regulations/Pages/FIAFormulaOneWorldChampionship.aspx

[19] http://f1-dictionary.110mb.com/f_w_endplate.html

[20]http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained

/wing_profiles_front/

[21] http://www.formula1.com/news/technical/

[22] http://en.wikipedia.org/wiki/Formula_One

[23] Cranfield Team F1: The front wing - F Mortel, Cranfield College of Aeronautics (2003)

http://www.f1technical.net/features/3893

http://www.formula1.com/inside_f1/understanding_the_sport/5281.html

http://en.wikipedia.org/wiki/Rumpler_Tropfenwagen

http://en.wikipedia.org/wiki/Automobile_drag_coefficient

http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained/wing_profiles_rear/

http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained/wing_profiles_rear/

http://f1-dictionary.110mb.com/nose_cone.html

http://en.wikipedia.org/wiki/1970_Formula_One_season

http://www.atlasf1.com/2000/feb16/gray.html

http://f1-dictionary.110mb.com/start_page.html

http://formula1techandart.wordpress.com/?s=splitter

http://insideracingtechnology.com/tech104gurney.htm

http://www.f1technical.net/articles/11878?sid=02ad3ff803ccc230adc4eb92e091f955

http://www.f1technical.net/forum/viewtopic.php?f=1&t=5669

http://www.fia.com/en-GB/sport/regulations/Pages/FIAFormulaOneWorldChampionship.aspx

http://www.fia.com/en-GB/sport/regulations/Pages/FIAFormulaOneWorldChampionship.aspx

http://f1-dictionary.110mb.com/f_w_endplate.html

http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained/wing_profiles_front/

http://www.shell.com/home/content/motorsport/ferrari/technical_partnership/f1_explained/wing_profiles_front/

http://www.formula1.com/news/technical/

http://en.wikipedia.org/wiki/Formula_One


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[24] http://www.formula1.com/news/technical/

[25] http://en.wikipedia.org/wiki/Team_Lotus

[26] http://www.f1technical.net/f1db/cars/881

[27] http://www.fia.com/resources/documents/1518391260__24_10_2005_CDG_wing_2008.pdf

[28] http://www-static.shell.com/static/motorsport/imgs/544_wide/technical_partnership/

f1_explained/diffuser1.jpg

[29] http://kereta.info/wp-content/uploads/2009/02/mclaren-mp4-20-rear-diffuser.jpg

[30] www.racingrenders.com

[31] http://www.revozport.com/webpics/FERRARI/F430/Diffuser%20Fins/F430_press-

diffuser.jpg

[32] Les Dossiers Techniques de F1-Forecast – Dominique Madier

[33] Explanation and discovery in aerodynamics - Gordon McCabe (December 2005)

[34] http://www.f1fanatic.co.uk/2007/01/25/banned-flexi-wings/

[35] http://en.wikipedia.org/wiki/History_of_Formula_One

[36] Flow analysis around a rotating wheel - Emmanuelle Thivolle-Cazat, Patrick Gilliéron (June

2006)

[37] Aerofoil at low speeds with Gurney flaps - L. Brown and A. Filippone (Sept 2003)

[38] http://en.wikipedia.org/wiki/Gurney_flap

[39] http://www.racecar-engineering.com/articles/f1/449813/f-ducts-how-do-they-work.html

[40] http://www.gtplanet.net/forum/showthread.php?t=125471

[41] http://en.wikipedia.org/wiki/Monaco_Grand_Prix

[42] http://en.wikipedia.org/wiki/Autodromo_Nazionale_Monza

[43] http://www.racecar-engineering.com/news/opinion/446922/f1-overtaking-are-the-circuits-

to-blame.html

[44] http://www.modified.com/news/0708_sccp_lateral_g_skidpad_testing/skidpad.html

[45] http://en.wikipedia.org/wiki/Chaparral_Cars

[46] http://en.wikipedia.org/wiki/Downforce

http://www.formula1.com/news/technical/

http://en.wikipedia.org/wiki/Team_Lotus

http://www.f1technical.net/f1db/cars/881

http://www.fia.com/resources/documents/1518391260__24_10_2005_CDG_wing_2008.pdf

http://www-static.shell.com/static/motorsport/imgs/544_wide/technical_partnership/%20f1_explained/diffuser1.jpg

http://www-static.shell.com/static/motorsport/imgs/544_wide/technical_partnership/%20f1_explained/diffuser1.jpg

http://kereta.info/wp-content/uploads/2009/02/mclaren-mp4-20-rear-diffuser.jpg

http://www.racingrenders.com/

http://www.revozport.com/webpics/FERRARI/F430/Diffuser%20Fins/F430_press-diffuser.jpg

http://www.revozport.com/webpics/FERRARI/F430/Diffuser%20Fins/F430_press-diffuser.jpg

http://en.wikipedia.org/wiki/History_of_Formula_One

http://en.wikipedia.org/wiki/Gurney_flap

http://www.racecar-engineering.com/articles/f1/449813/f-ducts-how-do-they-work.html

http://en.wikipedia.org/wiki/Monaco_Grand_Prix

http://en.wikipedia.org/wiki/Autodromo_Nazionale_Monza

http://www.racecar-engineering.com/news/opinion/446922/f1-overtaking-are-the-circuits-to-blame.html

http://www.racecar-engineering.com/news/opinion/446922/f1-overtaking-are-the-circuits-to-blame.html

http://en.wikipedia.org/wiki/Chaparral_Cars

http://en.wikipedia.org/wiki/Downforce


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[47] The Influence of Aerodynamics on the Design of High-Performance Road Vehicles - Part 2, by

Guido Buresti, University of Pisa (Italy), March 2004

[48] Race Car Aerodynamics – Corrado Casiraghi, Royal Institute of Technology, Stockholm, May

2010.

[49] http://en.wikipedia.org/wiki/Drafting_(aerodynamics)

[50] Aerodynamic effectiveness of the flow of exhaust gases in a generic formula one car configuration - F. L. Parra and K. Kontis, University of Manchester, September 2006

http://en.wikipedia.org/wiki/Drafting_(aerodynamics)

formula 1 aerodynamics - front wings (2010)

Documents

centreline downwash generating

red bull rb4

force india vjm02

low aspect ratio

honda dumbo wings

tooth gurney flap

miscellaneous control surfaces

high downforce setting