The Formula One Monocoque

Before proceeding, take a few moments to observe the picture below.

 

Yes, you guessed correctly. This is the monocoque of a Formula One car (The 2009 renault to be more specific)

The monocoque can, for all practical purposes, be referred to as the chasis of the F1 car. However, that would be belittling its more important title of ‘the drivers safety cell’! Invented by the legendary designer and lotus team boss, Colin Chapman, the monocoque today has become the single most important component of the safety package of an F1 driver. While the design of the monocoque is primarily looked at from the point of view of aerodynamics, the stress being put on the safety of a driver has led to a lot of research with regards to the construction and material of the monocoque. 1962 saw the debut of the monocoque made out of Aluminium. Over the next few decades, teams have striven really hard to improve the aeordynamic design and safety of the monocoque. So much so, that today teams develop the monocuqes that are designed to be a perfect fit to the driver, thus ensuring that the structure remains as narrow as possible from an aerodynamic point of view. 

The pinnacle was reached with the advent of Carbon Fibers. When they were introduced, the teams didn’t really have the funding or equipment to design the monocoques themselves. As a result, this task was left to the Aircraft industry. Today though, every team designs the monocoques themselves with the strictest of regulations. 

Consider the crash of Giancarlo Fisichella at Silverstone in 1997. A post mortem of the crash revealed that the Fisichella’s Jordan car had slowed from a speed of 230 kkm/hr to 0 in about 0.7 seconds. This would roughly be similar to a fall from a height of 200 meters. Sounds scary right? 

The fact remains though, that Fisichella only suffered minor injuries. One shudders to think of the consequences had he not been protected by a super awesome carbon fiber monocoque. Carbon fibre is a composite material that is twice as strong as steel, but five times lighter. It consists of up to 12 layers of carbon fibre mats, in which each of the individual threads is five times thinner than a human hair. A honeycomb-shaped aluminium layer is inserted between these mats, which increases the rigidity of the monocoque even more. In short, carbon fiber monocoques are, if not indestructible, quite difficult to crack!

And so they should be, as the FIA has extremely strict regulations with regards to the crash tests of the monocoques. Essentially, it can safely be said that Formula One has never been this safe, despite the wheel-to-wheel racing at 300 kmph!

Evaluating the Aerodynamics

While the system isn’t quite new, the Red Bull Racing Team decided to implement an interesting system to evaluate the aerodynamics around the sidepods of their car. 34 Pressure sensors are fitted on the custom made grid which gathers data while the vehicle is out on track during testing.

Quite interesting, to say the least!

The Oh-so-ugly F1 nose!

Firstly, let me make it very clear when I say that I do not find the noses ugly in any way. I do agree that it looks unconventional, but that is to be expected. Over the years, the design of the F1 cars have varied greatly, and yet, this is the first time that the fans have gone up in outrage exclaiming about how the nose looks. Adjectives such as crooked, ugly, beastly and horrid have donned the front pages of F1 newsletters across the world.

 

Let’s see why the nose looks so weird. New FIA safety rules mandate the nose be lower in the extreme front to reduce side-impact penetration, and higher further back to retain downforce. Some teams have chosen a two-tired design, others an extreme downward slant.

One advantage of having higher noses is that it improves the flow of air under the car and into the sidepods.

However, as the height keeps increasing, the center of gravity of the car is raised, and this adversely affects the balance of the car. Moreover, the aerodynamic properties are also affected. 

The teams decided to go in for a compromise and decided to have a small bit of both effects. Hence, most teams decided to opt for the stepped nose. The FIA has deemed it legal this year, but is considering a revision of the rules to ensure that the older design returns. 

However, the initial uproar about the ugly noses seems to have died down now, especially after we saw six race victors during the first six races. We are surely in for a cracking Formula One Championship for 2012!

The Manufacturing Process – The Very basics!

The article has been written after a lot of research on the internet and after referring various books and resources. Please feel free to e-mail me if you have any comments or suggestions regarding the same

• It’s made up of 80,000 components; if it were assembled 99.9% correctly, it would still have 80 things wrong with it!
•  It can go from 0 to 160 kmph AND back to 0 in FOUR seconds!
• On track, it is faster than the speeds at which smaller planes take-off for flight!
• In dry weather, the peak optimum operating temperature of its tyres is between 900 and 1200 degrees centigrade.

By now you’re probably thinking that these are quite impressive statistics. As you have rightly imagined, stats like these are not easy to get. Formula One teams spend an insane amount of time and money to ensure that the cars they create stand the best possible chance at surviving the conditions on a race track.

How exactly, though, is it all done? The race day performance of an F1 car is already decided at the design stage and a lot of work goes into the development of the car.  Let’s take a quick look into the birthing of a Formula One Race Car. As the complete article would be quite enormous, let us take a look at the most fundamental structure of any vehicle, the chassis.

Back in the day, racing cars were made up of the same things as a normal road car. The onset of the 1980’s saw a revolution of sorts, and thus began the age of the carbon fibre composites. This material has four major advantages over other materials used in building the chassis. It’s lightweight, super strong, super stiff and can be moulded into all kinds of different shapes reasonably easily.

Let’s take a quick look at how exactly the chassis is manufactured.

a)      Designed, analysed and developed by CAD and FEA software’s, solid epoxy patterns for the chassis are cut using five axis milling cutters, which read data from the CAD file and replicate the required dimensions. Epoxy is used instead of metal to ensure that when the moulds are undergoing curing at high temperatures, the effects of thermal expansion are minimized.

b)      Female moulds are made from these patters. Upper and lower moulds are produced, as the chassis itself is manufactures in upper and lower halves which are then bonded together. This work is carried out in a ‘clean room’, which is effectively a room sealed off from surrounding environments using double-door airlocks.

c)       The chassis themselves are manufactured from layered carbon-fibre cloth. The orientation of the fibre ‘plies’ (layers) is critical and they must run in specific directions according to the required stiffness properties of the structure. The number of plies and their orientation varies at different locations around the chassis. To ensure that the plies are correctly positioned, the staff carry out the lay-up work (layering of various carbon fibre plies) with reference to printed manuals containing annotated visual description to be followed for each ply. This is then rechecked before moving to the next step.

d)      The whole assembly is then placed in a vacuum bag and pushed into an autoclave (a large oven that provides thermal curing with precise control of temperature and pressure). The resin then cures, thus fusing all the plies together to create a single solid half of the chassis. The completed chassis halves are removed from the moulds, and are bonded together to form the final monocoque.

e)      Final machining and trimming of the finished chassis is carried out to produce any required detailing and to accommodate suspension pick-up-points, component mountings etc.

f)       Throughout the preceding steps, rigorous inspection procedures are followed at every stage. Parts are also returned for inspection between on-track events  and many parts have specified service schedules which may include NDT of bonded joints and the condition of laminates, stiffness testing, visual checking and cleaning/tidying up processes.

The above two pictures show the chassis of the LOTUS under construction and an Finite Elemental Analysis (FEA) of the stress distribution around the chassis

Although these steps provide a simplified view, the basic principles and procedures apply to all carbon-fibre components on the car. The main components of the chassis are the survival cell, the roll structures, the fuel tanks and ballasts.

The Survival Cell: The driver survival cell is an important feature. Apart from providing the driver with an extremely strong cocoon, the survival cell incorporates impact and rollover structures. The survival cell also incorporates side-impact-protection panels to reduce chances of parts of another car, punching through the side of the chassis and causing injury to the driver.

Roll Structures: In the event that the car becomes inverted during an accident, the FIA have specified that all cars must have two roll structures which must be incorporated into the chassis. The drives helmet and steering wheel must fall below a specified distance below the line drawn between the highest points of the two roll structures. Both Roll structures are subjected to load tests as part of the FIA regulations.

Fuel Tanks: The fuel tank is located in the chassis to the rear of the cockpit, behind the driver’s seat.  It is made from an elastomer-impregnated Kevlar material which is light and extremely flexible. The fuel talk is designed to deform if subjected to high-energy impact. The fuel pumps are carefully designed to ensure that every last drop of fuel inside the tank is used up.

Ballast: The FIA specifies a minimum weight limit of all cars taking part in a Formula One race. Thus, the teams ensure that the car is designed in such a way that it is at least 40-50 kg lighter than the weight limit. The remaining weight is provided in terms of ballasts. The ballasts are simple structures whose function is to distribute the weight around a car as desired. There is no restriction on the materials that can be used as Ballasts. Red Bull Racing, for example, made the use of Tungsten.

The chassis for any new car must undergo a series of FIA crash tests, all of which must be passed before the chassis is homologated and the car is allowed to race. The impact test is usually carried out at the Cranfield Impact centre near Bedford, with an FIA witness present. Various tests are carried out, divided into impact tests, roll-structure tests and push-off tests.

The chassis design is only a small part of the overall development process involved for an F1 car.  The aerodynamics, safety equipment, hydraulics, electronics etc. constitute a large amount of money and work-force. And with the advent of newer forms of technology every day, the design and development process in F1 is sure to become even more rigid and sophisticated.

F1 Jargon : The Flag Rules

The sport of Formula One has an insane number of rules. Many teams have special divisions that are paid to decipher the FIA rule book and to ensure that the driver and team is up-to-date with all the necessary requirements.

One of the most important things that a driver must learn are the flag rules. When a driver is out on track, the odds are very high that a flag is being waved at the next corner. The driver must then be in a position to observer and decipher what the flag is referring to. Given below is a list of the 10 important flags used during a Formula One race.

 

 

 

 

 

CHEQUERED FLAG
The race has ended.
The flag is shown first to the winner, and then to every car to cross the line behind him. The Chequered Flag originated to inform the driver that he had completed the requisite number of laps. Today, it is a more or less a mere formality. ‘To take the chequered flag’ is a common phrase used to refer to a driver having won the race.

 

 

 

 

 

 

 

 

 

RED FLAG
The race has been stopped, usually because a car is lying in a dangerous position after an accident or because conditions are too poor for racing to be safe. The red flag is shown subject to the decision of the race stewards. Considering the bullet-proof reliability that the cars in modern formula one boast of, the Red Flag is shown very rarely. However once the flag is shown, the race is stopped pending the approval of the stewards.

 

 

 

YELLOW FLAG
Indicates danger ahead and overtaking is prohibited. A single waved yellow flag means slow down, a double waved yellow warns that the driver must be prepared to stop if necessary. Many a times, drivers do not slow down enough when a yellow flag has been waved. Lewis Hamilton was penalized three grid places at the Inaugural Indian Grand Prix after the stewards felt that he had not slowed down sufficiently when the yellow flags were being waved. When required, a safety car is sent out to allow the teams for form up behind it and to ensure that there is no confusion.

 

 

 

BLUE FLAG
Shown to a driver to indicate that a faster car is behind him and trying to overtake. Shown both to lapped cars and those racing. A lapped car must allow the faster car past after seeing a maximum of three blue flags or risk being penalised. A racing car is under no obligation to move over.

 

 

 

 

 

 

 

 

 

BLACK FLAG
Shown with a car number to indicate that the driver must call into the pits immediately, usually because he has broken the rules and will be disqualified.

 

 

 

 

 

 

 

 

 

 

 

 

RED AND YELLOW STRIPED FLAG
The track is slippery. This usually warns of oil or water on the track.

 

 

 

GREEN FLAG
A hazard has been cleared up and the cars can proceed at racing speed. Generally shown immediately after the yellow flag. Drivers are always on the look out for the green flag, so they can continue racing immediately.

 

 

 

 

 

 

 

 

BLACK FLAG WITH AN ORANGE DISC
Shown with a car number to indicate that the car has a mechanical problem and the driver must return to his pit immediately.

 

 

 

 

 

 

 

 

WHITE AND BLACK DIAGONAL HALVES
Shown with car number to indicate a warning for unsportsmanlike behaviour. A black flag may follow if the driver takes no heed of the warning.
 

 

 

WHITE FLAG
Warns of a slow-moving vehicle on the track, such as a tow truck or safety car.

 

 

As one can understand, the decision to wave most of these flags depends on the Stewards discretion. Hence, a driver must be very careful to avoid any sort of confrontation and must stick to the rules. Be it Michael Schumacher or Daniel Riccardio, every driver on the track must be well aware of what the various flags mean.

Below is a video of Indian Cricket Legend Sachin Tendulkar waving the Chequered Flag for Sebastian Vettel at the Inaugural Indian Grand Prix.

The Slipstream – Drafting as an Art.

This is yet another term that is used very commonly by an F1 TV commentator. Motor-sport Racing in general, has many devices which facilitate an overtaking maneuver.  Proper usage of the Slipstream is probably the most natural means possible.  Many Racing Drivers spend hours in perfecting their approach while using the Slipstream.

As Wikipedia puts it, “Drafting or slipstreaming is a technique where two vehicles or other moving objects are caused to align in a close group reducing the overall effect of drag due to exploiting the lead object’s slipstream.”

To better understand the concept of the slipstream, have a closer look at the following picture.

The picture above shows the variation of Air pressure and the Air Flow over an average smart car. The area just behind this car consists of a region of Low Pressure. If you are someone who does not have a clue about how this happens, let me put it for you in a very simple way. The air pressure is a measure of the amount of Air Molecules present in a region. As you can clearly see from the diagram above, the region just behind the car will hardly have any air molecules compared to the area in front of the car. This creates a comparatively low pressure area. Due to the higher pressure in front, the car has a tendency to be pushed back, thus creating a dag force which reduces the overall speed of the car.

Now, imagine a car (say, Car B) that is following this one (say, Car A) pretty closely. Lets assume that the Nose of the following car, (i.e the frontmost point of Car B) enters into this low pressure zone of car A. In the context, this zone is termed as the Slipstream created by the car in front. As you can probably visualize, the air pressure in front of Car B is much lower than the pressure behind it, because of the slipstream created by Car A. This gives Car B a significant speed advantage over car A, and helps in overtaking on long straights.

The General term for Slipstreaming is ‘Drafting’. When applied to Open Wheel Racing, the term ‘slipstreaming’ is used.

On the faster speedways and superspeedways used by NASCAR, ARCA, and at one time the IROC series, two or more vehicles can race faster when lined up front-to-rear than a single car can race alone. The low-pressure wake behind a group’s leading car reduces the aerodynamic resistance on the front of the trailing car allowing the second car to pull closer. As the second car nears the first it pushes high-pressure air forward so less fast-moving air hits the lead car’s spoiler. The result is less drag for both cars, allowing faster speeds.

A Formula One Driver, when close enough to a car in front, tries his best to get into the slipstream. As Sebastian Vettel describes, “You can feel the slipstream once you get really close enough – It’s quite powerful and starts sucking you towards the other car.” However, the use of the slipstream is only justified during long straights. During Corners, the slipstream results in an insufficient airflow over the following car (i.e Car B). This leads to a reduction in downforce and ultimately a reduced cornering speed.

Computer simulation (computational fluid dynamics or CFD) is increasingly being used to analyse drafting. It is important to understand the aerodynamic behaviour of a motor vehicle when drafting, for example if the rear car is too close to the front car, the air supply to its radiator will be reduced and there is a possibility of the engine overheating. Most motor sport aerodynamic analysis is performed using wind tunnel testing. This becomes difficult for drafting cases, if only because a very large wind tunnel is needed. CFD, a kind of virtual wind tunnel, is used by race teams to understand the car’s performance while drafting.

Below is a video that aptly explains the concept of Drafting in IndyCar racing. (I apologize for not providing any F1 videos, but I assure you that the concept is similar)

The F-Duct : The F1 car snorkel!

The F-Duct sounds cheesy and vague. It does not sound half as fancy as the ‘Exhaust Blown Diffuser’ or the ‘Drag Reduction System’. The working of the F-Duct however, is as weird as weird can be.

The F-Duct is a crafty little system that was first used by the McLaren F1 Team. In fact, they initially called it the RW80. The media then went ahead and dubbed it the F-Duct, because the intlet of the F-Duct was at the ‘F’ of the ‘VODAFONE’ sign board on the front chasis of the McLaren car.

Observe the following picture.

Look carefully at the snorkel. That is the inlet of the F-Duct. You can see where it got its name from. The picture given below will provide you with a basic understanding of the working behind it.

Once the Air enters the F-Duct, it moves through a passageway till it reaches the driver cockpit. The default path leads it to act as a cooling system for the engine and the gearbox oil. The secondary pathway, which is shown in the picture above, is activated when the driver blocks the primary pathway with his hand or leg. This leads the air flow to pass through to the rear wing, which ultimately generates more downforce.

Though ingenious, the McLaren F1 team was unable to formulate a numerical model which described the advantages of the F-Duct. Soon enough, the snorkel could be seen on the Ferrari F1 car.  The thing about Ferraris F-Duct  though, was the fact that the driver had to use his left hand to block the primary air flow, which is understandably extremely dangerous.

The F-Duct was ingenious for two key reasons:

1) By using the drivers leg to direct the flow, the regulations are not contravened regarding movable areodynamic devices.

2) By incorporating the design into the monocoque it becomes very difficult for other teams to copy the device, due to the fact monocoques have to be homologated and changes are very expensive to make.

This fact led to a lot of teams raising a hue and cry about the McLaren solution for high downforce and the F-Duct soon turned into a huge controversy. The argument was that in this case, the driver acted as an aerodynamic device while blocking the air flow. And as moveable aerodynamic devices are banned in F1, the F-Duct had to go too. Here is an excerpt of the rules during the 2010 season for your clarification.

With the exception of the cover described in Article 6.5.2 (when used in the pit lane), the driver adjustable bodywork described in Article 3.18 and the ducts described in Article 11.4, any specific part of the car influencing its aerodynamic
performance :

• Must comply with the rules relating to bodywork
• Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom)
  
• Must remain immobile in relation to the sprung part of the car.

The FIA realised that the rules were not strong enough to ban the F-Duct during the 2010 season. The rules were revised after the season and the F-Duct has been effectively banned from the 2011 season.

Though the F-Duct lasted for a single season, the controversy it brought thrilled many Formula One enthusiasts. And while many believe that McLaren (for want of a better word) cheated, I strongly insist that this was ruthless technological advancement at its best. Hats off.

Exhaust-Blown Diffusers – The new Face of Formula One

Valencia 2010. Ferrari, Renault, Mercedes decided that they had had enough of sitting around waiting for things to happen. They decided to ‘copy’ a certain Technological development that was first seen on the RB6 (Red Bull Racing Car). What followed was a series of incredible lap times, lots of head-scratching and the beginning of a full-fledged controversy.

For those of you who are relatively new to Formula One, hello and welcome. Here’s what happened. Early in 2010 Adrian Newey, Red Bull Racing’s Chief Technical Engineer decided to go ‘back-to-the-future’ by introducing an old concept in the form of Exhaust Driven Diffusers. In fairness, the system has been present for a while now in racing, but created headlines only in the 2010 season. Once the other teams saw how successful the EBD (Exhaust Blown Diffuser) was, they decided to implement it in their own cars. The 2011 season saw a slight modification of the EBD, where Adrian Newey decided to opt for Off-Throttle Exhaust Blown Diffusers.

So what are Exhaust-Driven Diffusers? I’ll provide you with a short explanation and will try to keep it as simple as possible. Have a look at the following picture.

See the first position. This is the starting position, the piston will then start moving downwards during the Intake Stroke. This is when the Air and Fuel enter the cylinder and get mixed. The piston then moves back up and compresses the Air-Fuel mixture during the compression stroke. The spark plug (which is the central thing at the top) provides timed combustion charges that will ignite the fuel mixture. As the gases combust, they expand and eventually the gases go out through the outlet valve, (the red one) as exhaust gases.

In my previous post about diffusers, i mentioned about how cars manage to generate a lot of downforce by letting the air-flow pass through the diffusers. Newey, and subsequently every other car-designer on track, designed the car such that the exhaust gases, that come after combustion in the engine, flows through the diffuser. As this increases the amount of energized gas that was flowing through the diffuser, this provides the car with more downforce and amazing performance. This is where the saga of Exhaust-Driven Diffusers began. The FIA took note of this new development but remained silent, the reason for which is still not very clear. Sebastian Vettel won the world Championship, Red Bull won the constructors Championship, and apart from some grouchy faces on the Ferrari and Williams pit-walls, everybody was happy. This Technological development however, cannot be termed as ‘new’, as Renault had implemented it as early as in 1983.  Formula One then shifted from Turbo-Charged engines to Normal aspirated. This meant that the flow out of the exhaust was no longer smooth, and it would depend on the throttle position. (Running the car on full-throttle would produce more exhaust gases and hardly any exhaust would be produced when the car was not on throttle. This is easy enough to understand as when the driver is not on the throttle, there is no mixing of the fuel and air and finally no gases blowing out through the exhaust. This meant that the downforce would be produced only at certain times, and it led to some stability issues for the cars.

The 201 Formula One Season arrived. Red Bull dominated the first race at Albert Park with Sebastian Vettel winning the race after starting from pole position. Another thing that was to be noted was the fact that Red Bull Racing began to destroy the opposition during every single qualifying stint. (Q3 in particular) It wasn’t long before the Formula One world realized that Red Bull Racing had been very cleverly playing around with the mapping of their engines.

Engine-mapping. Now this is where you get to see Adrian Neweys genius side. He figured that if there was a way in which he could make the exhaust gases keep flowing all the time, even when the driver is not on the throttle, he would be able to produce an almost unbeatable aerodynamic package. And this is exactly what the Red Bull Racing Team did.

For your reference, let me provide you with the picture once again.

Note the inlet (blue) and outlet (red) valves on the top. The inlet valve opens when the piston begins to move down for the intake stroke. The timing of the opening and closing of the valves and the ignition is controlled electronically. What Adrian Newey did is this. He adjusted the timings in such a way, that even when a driver is not on the throttle, there is some amount of exhaust gas flowing out through the outlet valve. This is easy enough to understand. The engine mapping is designed such that the intake of gases begins even during the exhaust stroke, and vice versa. The explosion for the ignition takes place very close to the valves.

Now having the explosions happen so close to the value and the presence of weaker exhausts walls leads to a heavy load on the engine. Do that for 10-15 laps in succession and your engine life is down the toilet. You can’t cool them well enough for that as the packaging is just too compact. The valves and the exhausts will crack and catastrophically fail a chamber or more.  Yet, Red Bull is quick. They have managed to design the package such that the positives are way more than the negatives.

The FIA finally decided that they had had enough. The FIA decided to intervene and ban the Off Throttle Exhaust Blown Diffusers. (Well, not exactly ban, all they did was restrict the maximum amount of engine power that can be used when a driver is not on the throttle).

The FIA regulations consist of a clause which states that there can be no moving parts on a car which are designed to improve aerodynamic efficiency. This is the reason that they provided for restricting the use of off-throttle exhaust diffusers. They stated that this effectively improved aerodynamic efficiency, and that since the piston and cylinder were moveable parts, the system had to be banned.

This ban however did not affect all the teams. As only the Renault engines were highly dependent on the exhaust blown diffusers, the cars running Renault Engines were most affected (Red Bull, Renault and the Lotus teams)

Eventually, Red Bulls advantage was diluted. The Ferraris and McLarens rejoiced. The FIA had people throwing tomatoes at them.

And now, what has changed? NOTHING. Vettel was still on Pole for the Belgian Grand Prix, and he went on to win. Its obviously going to take some brilliant strategising and designing to stop the Red Bull rampage. For the time being however, Seb is on the path to glory.

 

 

Mike Gascoyne Explains Exhaust Blown Diffusers

Animations describing Ferraris Exhaust Blown Diffuser

Drag Reduction System (DRS) in Formula One.

In the past, how often have you watched a pole-sitter leading 90% of the laps and moving on to win the race. Not very often, actually! Then why the DRS? Though I fail to understand the necessity of the Drag Reduction System in Formula One, I do agree that this is Technology at its simplest best. The post will familiarize you with the use of the rear wing and the Drag Reduction System.

Everything started with the Rear Wing. Over the years, it has been a common topic of discussion in an F1-crazy bar. Take a look at the following picture.

This is a picture of the Lotus 49b used way back in 1968. The Lotus team stuck the rear wing up on a pair of broom handlers. It fell off so often that the FIA had to ban it immediately.  A series of crashes and major accidents in the 1960s led to the drastic restriction of the rear-wing technology. But as you can expect with Technology, they could not keep it shut inside a bottle.

The picture below shows you what a Rear Wing is. As I have explained in an earlier article on aerodynamics, the wings on an F1 car help in increasing the Downforce. I had also mentioned that this comes at a cost. An increased amount of Drag, which is undesirable.

The Drag Reduction System, as the name suggests, reduces drag. The picture below shows a Mercedes Driver opening the flap on the rear wing.

    

Here’s how it happens. When a driver opens the flap, the Air-flow over the car is disrupted greatly. The Aerodynamics crumble and the Downforce is greatly reduced. But what this effectively means, is that the Drag is reduced as well. This enables the car to go faster as there is no drag force opposing the cars motion. Calculations have shown that the DRS provides a car with an extra 12 kmph of straight line speed compared to a car that does not use it.

Though the mechanism seems fairly straightforward, a lot of things have to be taken into consideration while preparing for the use of DRS. The following is from the official FIA rulebook.

FIA Regulations

3.18.2 The adjustable bodywork may be activated by the driver at any time prior to the start of the race and, for the sole purpose of improving overtaking opportunities during the race, after the driver has completed a minimum of two laps after the race start or following a safety car period.

The driver may only activate the adjustable bodywork in the race when he has been notified via the control electronics that it is enabled. It will only be enabled if the driver is less than one second behind another at any of the pre-determined positions around each circuit. The system will be disabled by the control electronics the first time the driver uses the brakes after he has activated the system.

The FIA may, after consulting all competitors, adjust the above time proximity in order to ensure the stated purpose of the adjustable bodywork is met.

The FIA’s current plan is for the overtaking zone – where the moveable wing will be made active in races – to be the final 600 metres of a track’s main straight.

A driver pursuing a rival will only be able to activate his wing there if he is within one-second of the car ahead of him at a timing zone that will be set-up in the braking area for the corner before that main straight.

The FIA believes that the 600-metre passing zone is the right length to ensure that overtaking is possible – but is also not too easy. Early simulation data suggests that this length of track will result in a speed differential between cars of between 10-12 km/h depending on car design.

Drivers will be also free to use the wing at will during practice and qualifying.

To help Formula 1 fans and television commentators understand the implementation of the rules better, lines will be painted on the track to mark out the overtaking and timing zone.

A single line on the straight will show where the overtaking zone starts, while two lines will be painted at the preceding corner to indicate the one-second time difference distance. This latter line will also serve as a visual back up for the FIA should the official timing transponders fail at any point.

Lets analyze the pros and cons. Rather, does the Drag Reduction System actually make that much of a difference. F1 fans across the globe have been making a hue and cry about the fact that the DRS aids a driver a little too much, and that a drivers skills are being undermined in todays Formula One world.

The overall length of an F1 car is just about 5 meters. Logically, for a car to cross a car in front, it has to cover a distance of 3 car-lengths along with some clearance to avoid accidents. We assume that the car must not get closer than 2 meters to the car in front to pull out for an overtake. On that basis the following car must cover at least eighteen metres (5 + 5 + 5 + 2 + 1) to safely pass the other car. A skilled driver will force his opponent to overtake him from the wrong side, so that he will have to move again to get back on to the racing line. He will not need to change his line more than once which he is allowed to do within the present rules.

The calculations made below are based on those found elsewhere on the internet, along with a few tweaks. While the numbers are not perfect and there have been many assumptions made, the data comes very close to reality.

To do a proper calculation of the effectiveness of the low downforce wing positions, we must make some assumptions. They are as follows:

• Two cars reach the “wing deployment” line almost equal and almost side by side.
• Neither car uses Kers
• Both cars have equal speed at the line, for this example, 300 kph.
• One does not use the wing (A) due to regulation
• One does use the wing (B)
• The total distance covered is 600m

Here is the formula for car A:

(600m/300,000m) * 3600secs = 7.2 seconds to go 600m at 300 kph

1 hour =3600 seconds

Here’s the formula for car B:

(600m/312,000m) * 3600secs = 6.92 seconds to go 600m at 312kph (300 kmph + 12 kmph)

Results: car B covers the 600m .28 seconds faster than car A, as 7.2 – 6.92 = .28 secs

Is that enough of an advantage to make the pass? It depends on how much distance a car covers in .28 secs at an average of 312 kph.

If one (B) goes 600m in 6.92 secs they travel 1m in 6.92secs/600m = .011533….sec per meter

If the speed advantage using the “wing down” gains .28secs, then the formula is .28secs/.011533 secs per meter = 24 meters gained over the other car. 24 meters is enough. The pass could be made.

The calculations made above however are extremely idealistic, and yet have been derived from stats provided by the FOTA (Formula One Teams Association). In reality, many other factors will have to be considered like the fact that the cars will not be going side-by-side, they will not be going at the same speed and that the option of KERS will be available to the cars.

Finally, ask yourself this. Is the DRS that bad? There are only two designated areas on an F1 track where the DRS can be used.  Bear in mind however, that every single team can use this. This nullifies any advantage that one team may have over the other. Even if both the cars keep using DRS, it eventually boils down to which car is faster.

The Drag Rediction System is still in testing stages. The FIA has agreed to review it at the end of the season. If the season so far is anything to go by, chances are high that the DRS will continue being used next year as well.

Diffusers. The good, the bad and the controversy!

Any person who has been following Formula One over the last 2-3 years will have heard the term ‘Diffuser’ used over and over again. Many feel that the Diffuser is a new addition to Formula One Racing. The fact is that Diffusers have been around for decades, and managed to remain silent without inviting controversy. A revolutionary rule change in the 2009 Formula One Season sparked off a controversy, that has continued ever since and changed the face of Formula One.

Well, you know the drill. Let me explain exactly what a diffuser is. I’ll start by telling you what a diffuser is in the context of a general automobile. Take a look at the following picture.

Notice the underside of the Cars body. There are two broad areas. A darker shade of grey and the other one is the lighter shade of grey. As the air flows from under the car, it is constrained to flow in the light-grey area. As you can imagine, the area of the airflow has decreased. Now, there is an interesting equation which relates the area through which a fluid flows, with the fluids velocity. The equation says that they are inversely proportional.

Coming back to the above picture. As the area decreases the velocity increases. Good.

Remember a guy I spoke about in one of my earlier posts? A guy called Bernoulli? Well, his theorem comes into play once again. As the velocity of air under the cars body has increased, the pressure decreases. This leads to the car being pressed down onto the ground, thus increasing downforce. As I mentioned in my post on downforce, the F1 teams strive to extract every bit of downforce from their cars, and so the shape of the underside is extremely crucial. The Picture below shows the underside of an Indy Racing Car.

Now, return to the first picture and look at the rear end of the car. The portion shaded in pink. This is the part of the diffuser that expands the flow of Air from under the car as it leaves the car. This helps a racing car in two ways.

1) A phenomenon called “Pressure Recovery” occurs. As the air slows, there is an increase in pressure (as the molecules have to get closer to each other). This requirement forces air to be pulled into the diffuser (the underside) to allow this pressure increase to occur. The most effective diffusers are closed on the sides by walls that extend close to the ground (Look at the picture of the Indy car), in effect forming a sealed tunnel only open at the ends. Because air cannot come in from the sides, it is forced to accelerate through the entrance of the diffuser to fill it. This acceleration decreases the pressure of the air at the inlet of the diffuser creating downforce. If a smooth undertray is present at the entrance to the diffuser, this low pressure has more area on which to act, creating even more downforce. It is not actually the diffuser that creates downforce, it is the area in front of it.

2) While this effect is significantly lower, it plays an important role. You see, the area immediately behind an automobile generally has very low pressure. Normally this low pressure behind the car forces the air in front of the car to push it backwards, thus creating ‘drag’. This is because there is a shortage of ‘air molecules’ in this area. Diffusers help in ‘filling the void’ and this increases the pressure and ultimately reduces the drag.

Though they seem relatively simple and uninteresting, a diffuser is one of those parts on an F1 car, on which a designer can go crazy with innovative ideas. Teams spend a lot of time and money on research in the field of diffusers. And this sometimes can be a problem.

In 2009, the FIA introduced new regulations. The new regulations limited the main part of the diffuser to a width of 1000mm, a length of 350mm and a height of 175mm. All of the channels had to be of the same height and length, with no difference in height between the main central section and the side channels.

McLaren, Ferrari, Renault and BMW Sauber made literal interpretations of this rule and designed their diffusers accordingly. Brawn GP, Williams, and Toyota, on the other hand, exploited a loophole in the rules that says that the diffuser is merely one section of the wider bodywork structure. Have a look at the picture below.

“Toyota’s diffuser makes a very interesting interpretation of the revised 2009 rules (and one that has already prompted speculation regarding its legality),” explains the official Formula One website. “By exploiting regulations that allow extra bodywork within a 150mm zone in the centre of the car, the team appear to have cleverly shaped the TF109′s (Toyotas 2009 car) rear crash structure (the rectangular greyish structure just above the yellow) so that it effectively lengthens and heightens the diffuser’s central section, which also features a very low splitter at its base. Like engine supplier Toyota, Williams’ interpretation of the revised diffuser regulations is highly innovative. Much of the diffuser’s central section is actually lower than the outer sections. However, clever shaping of the rear crash structure immediately below the rear light effectively creates a second central section. In combination, the result is a central section that exceeds the 175mm height allowance that applies to the diffuser alone.”

Additionally there is an ambiguous rule which appeared to allow the teams to use a part of the bodywork as part of the diffuser.

All three teams (Toyota, Williams and Brawn GP) created a “double-decker diffuser” as a result of this. While their main diffuser was as long, wide and tall as the rules allowed, they made the middle section stop short of meeting the flat floor, and instead the floor extended into the upper diffuser creating an opening to allow airflow above the main diffuser which created more diffuser exit area, and the higher expansion of the flow through the diffuser created more downforce.

The Ferrari, McLaren, Renault and Sauber cars did not have the ‘holes’ in the diffuser and the main point of debate was whether the ‘three sections’ in the Brawn Car could be considered as a single entity.

What made matters worse was the fact that the 2009 World Drivers Championship and Constructors Championship was won by Brawn GP, which left the Ferraris and the Mclarens infuriated.

The FIA, however, allowed the double diffuser to be legal in 2009 and thus let Jenson Button hold onto his Drivers Championship trophy. The double diffusers have been banned since 2010. But as one can expect, the diffusers can never stay away from controversy, with Red Bull Racing’s ‘Exhaust Blown Diffusers’ making headlines in 2011. More on that, however, in a future article.

Meanwhile, enjoy this short video about Williams F1’s 2009 cars rear diffuser.