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A Paper on
AERODYNAMICS IN ACTION
FORMULA ONE CARS
Presented at TECHNOFEST-2010
Organized by VRSEC
Presented by
Krishna Kanth KVSS
Ph No-9553794862
Department of Mechanical Engineering
Jawaharlal Nehru Technological University
Kakinada
East Godavari
Andhra Pradesh -533 003
India
Index
Aerodynamics in Action-Formula One cars
-Abstract
-Introduction
-Earlier Developments
-F1 configuration
-Streamlining the body
-Downforce
-Base Design
-Front wing
-Rear wing
-The high nose
-Diffuser
-Angle of attack
-Conclusion
-References
Aerodynamics In Action
Formula One Car
Abstract
Aerodynamics in Formula One racing is often described as a black art, the real secret to success
on the track .In the tough struggle for crucial seconds in Formula 1, aerodynamics play a
fundamental role .Small impact make the difference between success and failure. A small
change in aerodynamic structure can make the difference. A modern formula one car is a
technical master piece. Aerodynamics in formula one deals with how effectively we utilize the
air, in favor of requirement of us and not considering it as a frictionally force .Any person
driving his/her car at 120-150 KMPH finds it very difficult to control it. But any one has ever
imagined how difficult it is to control a car at 300-350 KMPH on road. Practically not possible,
but it is all made to work by aerodynamics. With the available technology it is not difficult to
manufacture an engine which can run at speed on par with the speed of sound or even greater,
but the thing is how effectively a driver controls it on the road. There the role of aerodynamics
comes into play. In a sport obsessed with attention to detail, the aerodynamicists are more
obsessive than most. The teams invest up to 20% of their total budget in the science of the
winds, making their cars even faster with innovative aerodynamic designs. Meticulous
precision work is undertaken down to the last millimeter, according to the motto; races are won
in the wind tunnel and lost on the track.
INTRODUCTION
First and foremost, aerodynamics is the science of manipulating and making use of airflow. Put
simply, aerodynamics deals with the flow of air and how it reacts with bodies in motion. A
windmill and an aero plane are both examples of aerodynamics in action. In Formula One
racing, high speeds means the air is a formidable force presenting an obstacle to speed but it can
be used to the car’s advantage as well. The following deals with different parts of the formula
one car aerodynamically streamlined so as to get maximum performance on the track. The
paper entirely revolves around the downforce developed on the car
Early Development
In the 1960's the use of soft rubber compounds and wider tyres , demonstrated that good road
adhesion and hence cornering ability, was just as important as raw engine power in producing
fast lap times. The tyre width factor came as something of a surprise. In simple school
experiments on sliding friction between hard surfaces, the friction resistance force is found to
be independent of the contact area. It came as a similar surprise to find that the friction could be
greater than the contact force between the two surfaces, apparently giving a coefficient greater
than one. The desire to further increase the tyre adhesion led the major revolution in racing car
design, the introduction of inverted wings, which produce negative lift or 'down force'. Since
the tyres lateral adhesion is roughly proportional to the downloading on it, or the friction
between tyre and road, adding aerodynamic down force to the weight component improves the
adhesion.
F1 configuration
F1 can be considered to be canard configurations in the sense that the front and back wings are
on opposite sides of the centre of gravity and both are "lifting" (strongly) in the same direction,
in this case down. The car should be considered in (at least) 3 parts; front wing, body and rear
wing. Each of these parts should be optimized for down force (i.e. "lifting" down) and low drag,
with the accent very definitely on down force. This down force can be likened to a "virtual"
increase in weight, pressing the car down onto the road and increasing the available frictional
force between the car and the road, therefore enabling higher cornering speeds. This allows
today's formula-1-cars to withstand centrifugal forces from 4G as to where a passenger car with
sport chassis begins to slip at 1G.
Streamlining the body
An important aspect of aerodynamics is the drag, or resistance, acting on solid bodies moving
through air. The drag forces exerted by the air flowing over the car must be overcome by the
thrust force developed by the engine. These drag forces can be significantly reduced by
streamlining the body.
A streamlined shape is one with a contour that is itself a streamline (such as the airfoil below),
or its shape is such that its resistance to the flow of air, water, or another fluid past it is
minimized. So when we talk about streamlining a body, we are trying to smooth out the
external contours of the shape to create a streamlined flow over it and reduce the flow's
resistance to that motion. This resistance is what we call drag, and this particular kind of drag is
referred to as form drag. For bodies that are not fully streamlined, the drag force increases
approximately with the square of the speed as they move rapidly through the air. The power
required, for example, to drive an automobile steadily at medium or high speed is primarily
absorbed in overcoming air resistance. The more streamline a vehicle is, the less power it needs
to obtain high speeds, and therefore is more economical.
Downforce
Aero foils in motorsports are often called wings, referring to aircraft wings. In fact they are very
similar. F1 wings and winglets aim to generate high downforce, by having a high angle of
attack, thus also increasing the drag of the aerofoil. The evolution of an airfoil to what it is now
is mainly thanks to Bernoulli and Newton, who initially had totally different views on
generating downforce. When a gas flows over an object (or when an object moves through a
gas), the molecules of the gas are free to move around. They are not closely bound to one
another as in a solid. Because the molecules move, there is a velocity (speed plus direction)
associated with the gas. Within the gas, the velocity can have very different values at different
places near the object. Bernoulli's equation relates the pressure on the object to the local
velocity; so as the velocity changes around the object, the pressure changes as well, in the
opposite way.
Bernoulli Newton Today
Now adding up the velocity variation around the object instead of the pressure variation also
determines the aerodynamic force. The integrated velocity variation around the object produces
a net turning of the gas flow. From Newton's third law of motion, a turning action of the flow
will result in a re-action (aerodynamic force) on the object. So both "Bernoulli" and "Newton"
are correct. Integrating the effects of either the pressure or the velocity determines the
aerodynamic force on an object. These two equations have lead to the current airfoils used and
make optimal use of both theories.
Base Design
Formula One reverses the principles behind an aeroplane wing.In simple terms, an F1 wing is
designed so that air flows more rapidly over its lower surface than the upper. This creates an
increase in pressure on the top surface compared to the bottom. The resulting pressure
difference creates a downward pressure, which we call downforce.This relatively simple
concept is made more complex by the relationship between downforce and drag. A wing is so
designed that air flows more rapidly over its upper surface than its lower one, leading to a
decrease in pressure on the top surface as compared to the bottom. The resulting pressure
difference provides the lift that sustains the aircraft in flight. If the wing is turned upside-down,
the resultant force is downwards. This explains how performance cars corner at such high speed
The 'downforce' produced pushes the tyre into the road giving more grip.This down force helps
the car to firmly grip to the ground. During the turnings of the car the down force compensate
to the high centrifugal force on the car giving it high stability. This makes the car to achieve
high speed. A modern Formula one car when travelling at high speed can produce a down force
which is sufficient for the car to go upside down on the roof of a construction.
Front Wing
The front wing is vital to the entire car, as it is the first part to come in contact with the air, and
must be able to leave it relatively undisturbed, whilst producing sufficient downforce for grip
on the front tyres . It affects the airflow down the full length of the car and even tiny changes
can have huge effects on the overall performance. The front wing accounts for approximately
33% of the total car downforce. The front wing end plates reduce drag and also direct air over
the front wheels in attempt to reduce the drag.
The front wing is shaped to direct air to the underside of the car and ultimately feed the
undertray. Shaping is also employed to allow air to cool the brakes and radiators. The front
wing is a compromise between producing downforce and directing air to other areas of the
car.The front wing of a Formula One car is held by two vertical connectors, which also act to
shape the airflow underneath the car. The front wing consists of either two or three components,
all of which are Shaped and angled to produce the most downforce with the least amount of
drag. Each component is adjustable, such that its angle of attack can be altered to suit different
circuits, or even during a race in order to deal with understeer or oversteer. Whilst covers over
the wheels which sit on either end of the front wing, styled to direct airflow over the wheels
such that there is less turbulence as it travels over the rest of the car. Modern endplates often
have smaller wings protruding from the outside, producing a small amount of extra downforce
and aiding the correction of airflow.
Rear wing
The rear wing helps glue the rear wheels to the track, but it also hugely increases drag. This
means designers are constantly working to use as little angle of incidence on the rear wing as
possible without harming overall performance.The basic principle of a formula one wing is
exactly the same as with a common aircraft. The greatest difference is the direction air is
pressed and how that aerodynamic force is generated. Knowing that an aircraft wing does the
opposite of an F1 wing, the formula one wing is explained. With a single wing, we do not have
to think about turbulence that is generated by the car itself (the engine cover mainly), neither do
we have to take in account the direction and speed of outside wind. It is obvious that both these
factors decrease the efficiency of an aerofoil. As you can see in the picture above, air flows
onto the rear wing with a straight direction (which is often called clean air) at the speed of the
car. The white flaps push the air up. Following Newton's law, an action causes a reaction,
which is why the aerofoil is being pushed towards the ground by the air. Having in mind that air
flowing onto the flaps is pushed upwards, and underflowing air keeps going its own way, a low
pressure area (nearing a vacuum at very high speeds) is created right behind the horizontal
aerofoils. This 'vacuum' causes a suck up of the air passing under that flap. The underpassing
air on the other hand again flows faster in an attempt to equalize pressure on both sides of the
aeleron, and thereby increasing the total wing efficiency. Because of the car's speed this is
impossible, which is why the effect is maintained. The force that is created by this type of wing,
so that the car is pressed onto the ground, is called downforce.
The high nose
The nose cone of formula one car is similar to the nose cone of a modern aircraft .The main
advantages of a higher nose need some thinking and knowledge of the complete car to see. At
first sight the higher nose is equal to less downforce as by itself it pushes less air up over the
nose. Surprisingly the nose is not aimed to push air up, but instead small at the front to allow
air flow aside of the nose. The air that passes the nose forms the basic concept of a high nose
cone. Having such a nose allows air to go straight through under the nose instead of having to
bend around it. While it reduces drag for sure, the front wing planes can span the complete
width of the car which in fact allows more downforce to be generated at the front. All air that
passed under the nose is then guided under the car or split to either side of the car by the splitter
located just in front of the sidepods. But the sky is not all blue as there are also some
disadvantages to it. The nose itself of course does not generate much downforce; in fact the
higher the nose point the less downforce by itself (this does not include any downforce
generated by front wing or floor). Another disadvantage for the highest noses may be visibility
from the driver's point of view
The diffuser
The smallest thing which can count to the wings part is the
diffuser. Actually, it does exactly the opposite of a rear or
front wings. Instead of pushing the air up, it sucks the air
up. The volume of the diffuser increases towards to the
end of the car. Where a certain amount of molecules filled
for example 1dm³ under the car, these now fill 2dm³. This
drop of pressure causes a car to be sucked towards the
ground. Driving at a speed of 300 km/h, the ground effect of the car would be extreme if there
was no air under the car itself. Instead of raising the back of the car, the diffuser sucks the air
away from under the car because the low pressure. The diffuser is placed under the rear wing
and is actually a sweep up of the car's floor. It consists of many tunnels and spliters which
carefully control the airflow to maximize this suction effect. The design of the bottom of the
car, and thereby the diffuser is a critical area, because it can greatly influence the car's
behaviour in corners. More importantly, the designers have to be carefull that the car keeps
working well in all circumstances, and at any distance from the ground. Losing all of the
diffuser's generated downforce when riding over a curb will greatly generate a nervous
behaviour of the car itself. The strokes and flips withing the diffuser have lately become that
advanced that any track distance is insufficient to guarantee good performance. It is still a part
where a lot of time can be gained on current F1 cars, partly by pulling more air towards the
diffuser.
Angle of attack
Every part of the formula one car is assembled in such a way that it is at a certain angle to the
horizontal. The angle may be 0 degrees or above. This angle is called angle of attack. It is
called so because it is the angle at which the any part of a car faces the air. The angle of attack
depends on the situation on the day of race. It depends on the temperature, humidity of air, the
velocity of air, the direction of air flow (is it in the direction of track or opposite to it) and many
other reasons. The angles are set on the day of the race. These angles are decided by the
expertises because only immense experience can make you decide which angle to set. There are
no specific formulas or calculations to set the angle. Further more the change in angle of one
part will effect the functioning of another part. For example if we change the angle of nose cone
it deviate the air at different angle to the rear wing. Intern the rear wing has to be adjusted so as
to face the air properly. In this way change in a single part lead to the change in efficiency of
other parts. The front wing is normally kept at an angle between 0 to 15 degrees. The rear wing
is adjusted between 20 to 65 degrees depending upon air flow. The nose cone is kept at an angle
between 30 to 50 degrees. Every angle depends upon the day of race.
Concurring
It is the most nail biting war in formula one race. Every formula one car is designed in such a
way so as to face normal air and produce downforce through it. But when a formula one car is
behind another formula one car it donot face normal air as the front car does. The air it faces
will be highly turbulent in flow which is coming out of the diffuser of the car. This makes the
behind car inefficient to produce sufficient downforce so as to overtake the forward car. It is
this reason why the formula one regulating authority has imposed regulations on the diffuser of
the car. The diffuser has been widened at its end so as to facilitate the air to strike the behind
car effectively. Projector like things are also provided behind the car so as to divert it exactly in
the same way the car is facing the air But this is not the final solution to it and the
aerodynamists are working on this to decrease the problem
Conclusion
With the available technology of powerful engines, electronic transmissions it is easy to attain
high speeds but the problem is with the stability of the car on the track. until and unless a
proper aerodynamic design is added to the car outer built it cannot resist to the lift and
centrifugal forces produced on the car at high speed .without the advancement in aerodynamics
there is no improvement in downforce and without downforce there is no high speed stability
and without it we cant imagine a formula one race .That means without aerodynamics there is
no formula one.
References
BooksThe ultimate encyclopedia on Formula one by Bruce Jones, Damon hill
Internet
www.f1technical.comwww.wikipedia.org