The Formula One Monocoque

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

 

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!

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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!

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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.

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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.

Slipstream

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.

Air Flow through the F-Duct

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.