Sunday, November 29, 2009

Analysis of F1 engine performance in 2009

There is a great piece of work on Auto Motor und Sport’s website with an analysis of the engines in this year’s world championship. The analysis is based on collating the information each engine builder has about each other.

Engine
I’ve checked it out with some of the F1 engineers and it seems that the data is a pretty accurate reflection of the numbers they are working with.

The result is that Mercedes comes out top, with Toyota at the bottom.

Throughout the year one kept hearing stories about how much the Renault in the back of the Red Bull car was down on power compared to the Mercedes in the Brawn, Force India and the McLaren. In fact Renault were allowed to improve their engine quite a lot from 2008 to 2009 and it ended up not far off the performance of the Mercedes.

Most teams reached the conclusion, based on acoustic analysis and GPS, that the spread of engine power from the best to the worst engines was less than 2.5% this year. This means that, if the Mercedes is believed to have had 755hp, the least powerful engine was 18hp down, which is worth just under 3/10ths of a second per lap.

The BMW and Mercedes were at the top, with the Ferrari just behind, then the Renault and the Toyota. On this basis, given how close the lap times were between teams this year, the Toyota and Williams chassis must have been pretty good to withstand losing 3/10ths of a second through engine performance alone. Both teams had the double diffuser from the start of the year, of course.

Responding to rumours in the paddock about the performance of the Mercedes, the FIA took a Mercedes’ engine apart and tested it after Monza, giving it a clean bill of health.

Engineglow
The Renault won out this year on fuel efficiency, however, which was pretty important this year and will be much more important next year with no refuellling. Compared to the Mercedes, the Renault would go four laps longer on a full tank of fuel, which is worth about 3/10ths of a second per lap next year. The Ferrari was less efficient than the Mercedes, as we saw on several occasions this year.

As for next year, Cosworth is believed to be quoting a figure of 770hp, which is up on the Mercedes, but the fuel efficiency is still an issue and the unit is well short of the reliability testing of its peers.

Mercedes was given clearance by the FIA to supply a fourth team next year, but is not able to do so, due to the terms of its agreement with McLaren. Mercedes now owns the Brawn team, while McLaren has a technology partnership with Force India. So it is not in McLaren’s interests to add another competitor.

Red Bull is in limbo at the moment, waiting to see whether Renault, on whose engine its 2010 car is designed, will continue in F1. A decision is expected at the end of the year.

Saturday, October 31, 2009

Williams to use Cosworth engines in 2010

Williams confirmed on Friday that they have signed a long-term engine partnership with Cosworth Limited. The team announced earlier this month that they would be ending their current arrangement with Toyota at the end of this season.
“Cosworth have impressed us with the quality of their technical team and convinced us that their programme will deliver a competitive Formula One engine,” said Frank Williams, whose team last used Cosworth power in 2006.
“In addition, like Williams, Cosworth is an independent company whose owners share our passion for racing and engineering. We believe that, working together, we will develop not only a competitive racing car for 2010 but also a long-term partnership that can take on the best in Formula One.”
Mark Gallagher, Cosworth's general manager for Formula One, added: “Cosworth is delighted to be renewing our partnership with Williams. We look forward to forging a long-standing relationship, not only for the supply of competitive Formula One engines, but also in the joint development of new technologies that have wider application outside of Formula One.”
Cosworth powered both Williams and Toro Rosso in 2006, after which they departed the sport. Next year their engines will also be used by the four new Formula One entrants, Campos Meta, Lotus, Manor and the US F1 Team

Friday, October 30, 2009

Red Bull design new diffuser for RB5

Red Bull Racing have brought another aerodynamic step to its car at Singapore, and most notably that includes a new diffuser. The new design has changed mostly in the centre part of the car, around the double decked area. Where the older version focused on speeding up air on the lower channel, the new iteration has a bigger central channel around the crash structure to profit more of the DDD design. The central part is now very similar to the Renault or Brawn diffusers.
One detail marked in the image however are two small pointy extensions on both sides of the diffuser. Red Bull carefully copied that from McLaren and clearly found the additions efficient enough to use them.

Red Bull design new diffuser for RB5

Thursday, July 9, 2009

Nurburgring - a Formula One set-up guide

The Nurburgring has a reputation for being a 'complete' circuit in the sense that it includes a wide variety of corners. There are high-speed sections, medium-speed chicanes, and some very slow corners with high traction demands. The cars will have to meet all of these challenges this weekend. Overtaking is difficult but possible into the first corner and the chicane at Turns 13 and 14. However, the weather is a constant concern and no matter what the season, rain and cool conditions are an ever-present threat in the Eifel mountains. Renault explain how they plan to tweak their R29 for the German Grand Prix…


Aerodynamics
The Nurburgring demands some of the highest downforce levels of the season, not only for the numerous high and medium-speed corners, but also to maintain good stability under heavy braking for the first corner and the slow chicane of Turns 13 and 14.
As Renault driver Fernando Alonso explains: "The left-right chicane of Turns 13 and 14 is probably the best overtaking opportunity as it's one of the biggest braking zones of the lap. If you are following another car closely, you can pick up a good slipstream on the approach and make a lunge down the inside. We take it at about 100 km/h in second gear and you need to be aggressive with the curbs to straight-line the chicane as much as possible and carry speed through the corner."


Chassis balance
Corners such as Turns Five/Six, Eight/Nine and 10/11 in particular demand a neutral handling balance to avoid compromising the optimum line through the second corner in the sequence, and the engineers will often work through the weekend to dial out understeer in the medium-speed corners.
A quick, responsive change of direction is required in both the slow-speed section at the start of the lap, and through the quicker corners. Mechanical grip is particularly important through Turns One to Four, but cannot be achieved at the expense of aerodynamic performance around the rest of the lap.
Alonso explains: "The run through Turns One to Four is not very exciting for the drivers, but we spend a lot of time in them and that means that any mistake is likely to be very costly, especially in qualifying. We need to be precise with our braking and keep the car under control all the time as too much understeer, oversteer or a missed apex will put you out of shape for the following corners. The car balance is never perfect at such low speeds either, so we are always fighting understeer in the very slow corners, and a nervous rear end when we accelerate away."


Tyres
Tyre performance will, as always, be a critical performance parameter for all teams this weekend with Bridgestone providing the super-soft and medium compounds from its 2009 range. Ambient conditions will play a role in determining which compound is the preferred tyre for the race as we often experience cool temperatures at the Nurburgring.


Brakes
Wear on the brakes is not a major concern. None of the braking zones are particularly severe and there is no reason to think that wear levels on the discs and pads should be abnormally high as a result.


Engine
The Nurburgring is not a circuit that presents the engines with any extreme challenges, and its overall impact is further reduced by the fact that the circuit is situated at altitude, some 500m above sea level. This has the effect of reducing engine power by approximately five percent, while also reducing loads on certain engine components such as the pistons.
The engine is at full throttle for just over 64 percent of the lap - a value slightly above the season average of approximately 62 percent. The longest single period at full throttle barely exceeds ten seconds, so the main challenge for the engine team is ensuring strong performance from low revs so the engine launches well out of the slow corners, particularly Turn Seven which leads onto the uphill drag to Turn 10.
As Nelson Piquet explains: "We approach Turn Seven downhill in seventh gear at almost 300km/h before braking and downshifting to third for the hairpin. It's really important to stay online and hit the apex through this corner so that you can apply the throttle early on the exit to carry as much speed on the long drag back up the hill towards the high-speed chicane of Turns Eight and Nine."
The circuit includes a number of elevation changes, but none are sudden enough to cause the engine systems any concern. The only note of caution is finding the best line through some of the bumpier corners, and particularly the chicane, to avoid spending too much time on the rev limiter, which is potentially damaging for the engine.

Wednesday, July 1, 2009

Tyre disparity to be reduced at four GPs

bridgestone2009small

Bridgestone has announced that there will be a smaller than usual gap between its tyre compounds in the Hungarian, European, Belgian and Italian Grands Prix.

Normally this year Bridgestone has tried to make the two compounds that must be used in each grand prix 'two steps' apart - for instance super soft and medium tyres rather than super soft and soft. This system, which was requested by the Formula 1 teams, was designed to create greater variation between cars' performances at different stages, and to encourage better racing.

But the company's motorsport boss Hirohide Hamashima said Bridgestone had decided it would not be practical to have a big tyre disparity at the Hungaroring, Valencia, Spa or Monza, so would use compounds just one step apart at those four tracks.

"Hungary is a circuit where the characteristics demand our softest tyres," he explained. "This is also true for street courses, and we used the softest allocation earlier in the year at Monaco, and will again in Valencia.

"In Spa the weather temperatures can be quite cool, so the hard compound could have caused difficulties, and the super soft would have been too soft for this track, so that means the allocation of medium and soft is obvious.

"In Monza the hard compound would have given too big a difference between it and the soft, so we will bring the soft and the medium."

The only time Bridgestone had previously used two similar tyre compounds so far this year was in the Monaco GP.

Wednesday, June 10, 2009

New front wing for Brawn BGP001

The Brawn GP design team have been looking carefully at Ferrari's front wing compared to their own. Previously that resembled a lot to BMW Sauber's design as it features two upper flaps with the actuator mechanism in the middle of these flaps. The new wing however is completely different and sports only one flap. The most important advantage of this will be the adjustability for the drivers. Previously they only has control of a small panel of which they could change the angle of attack, but adjusting the new single flap by 6° will greatly change downforce at the front end.

BMW introduce their own Double Diffuser

BMW Sauber have taken a long time to design and manufacture a double decker diffuser to replace the more conventional one that followed 'the spirit of the rules'. The new version immediately proved effective as Robert Kubica was there within the points, while in Bahrain they were no where near the midfield.
The new diffuser resembles much that of Brawn with an empty keel structure in the middle and an early exit above it for additional downforce. It also pick up an idea of Toyota by creating a small extension to the diffuser under the rear crash structure - with the safety light, the only area where the diffuser is allowed to extend further behind the rear wheels.

Thursday, June 4, 2009

F1 2009: Turkish Grand Prix circuit guide

The lowdown:
The track was only built in 2005 but already Bernie Ecclestone has called this Hermann Tilke creation “the best racetrack in the world”. Fans and drivers rave about it too. The reason? It’s undulating, tough to drive, visually appealing and its wide track offers the chance to see wheel-to-wheel racing.

Most of all, though, it’s because of the hair-raising T8 with its triple apex, which has already invited comparisons with other legendary corners such as Eau Rouge and 130R. Interesting fact: Istanbul Park is one of four circuits on this season’s calendar to run in an anti-clockwise direction, the others being Brazil, Singapore and Abu Dhabi.

Overtaking opportunities?
Plenty. T12, at the end of the back straight, is where most of the overtaking happens, but there are also chances on T1, a blind left-hander, and of course T8 if the driver in front of you gets his line fractionally wrong through the triple apex.

What they say about it:
"The Istanbul Park track is fairly challenging from a driver's point of view as it runs anti-clockwise which is unusual and the undulations are quite extreme which can make for an exciting lap. The highlight for most drivers is the high-speed turn eight where the triple apex is really quick, blind and tough on your neck." Rubens Barrichello (Brawn GP)

Tuesday, June 2, 2009

Istanbul Park - a Formula One set-up guide

The purpose-built anti-clockwise circuit on the outskirts of Istanbul offers a mix of challenging low and high-speed corners and has already established its position as a firm favourite with the drivers. Overtaking is difficult, especially in the first half of the lap, but the long back straight leading into the tight hairpin of Turn 12 offers the ideal opportunity for a lunge under braking. Combine this with the challenge of Turn Eight, which is one of the most demanding of the year, and you have all the ingredients for an exciting Grand Prix. Renault explain how they plan to ready the R29 for racing…
Suspension
As a relatively new facility the track surface at Istanbul is in good condition and the kerbs are not especially aggressive, which makes it quite straightforward to find a stable car balance. Renault will seek a compromise between stiffer settings for the high-speed part of the lap to give a good change of direction, and softer settings for the low-speed section, particularly the final few corners to ensure good mechanical grip.
Driver Nelson Piquet explains: "It's quite difficult to find the right compromise with car set-up at Istanbul because the lap is so varied in terms of corner speeds and grip. The last three corners of the lap are the slowest on the circuit, taken in second gear at around 80 km/h. Turn 12 after the long back straight is the biggest braking zone of the circuit and offers the best overtaking opportunity of the lap. It's easy to make a mistake here and go in too deep, which puts you out of position for the final couple of corners and can cost you a lot of time."
Aerodynamics
There are few critical high-speed corners at Istanbul Park, but the team will still run with medium downforce settings in order to carry good speed through the long left-hander of Turn Eight, which puts high g-forces through the drivers' necks.
Fernando Alonso explains: "Turn Eight is one of the quickest and longest left hand corners of the year. It's really a series of corners with four apexes, although we treat it as one apex and try to be as smooth as possible with the steering inputs. We don't touch the brake at any stage through the corner, and simply lift the throttle slightly to keep the car online. In the middle of the corner we're doing about 260km/h and you can really feel the g-forces on your body. It's easy to understeer wide in this corner, which will cost you a lot of time, but there's plenty of run-off to save you."
While the aero grip keeps the cars glued to the track through Turn Eight, it is mechanical grip that predominates between Turns Three to Five and Turns 12 to 14.
Brakes
The braking zone into Turn 12 after the long back straight is the most significant on the circuit. It also represents the best overtaking opportunity and will normally see plenty of action during the Grand Prix. Overall the circuit is not particularly demanding on the brakes, which have enough time to cool on the long straights before the main braking zones, although with medium downforce settings the drivers may struggle with locking of the rear brakes.
Tyres
The Turkish Grand Prix is quite a demanding track on the tyres, largely due to Turn Eight which puts high loadings through the tyres, particularly the front right. To avoid any potential problems, we can adjust suspension settings and front wing angle; however, we must always be mindful of finding the correct balance between protecting the tyres and maintaining mechanical grip, to ensure the car is quick in the more technical parts of the circuit. Bridgestone will supply the hard and soft compounds from their 2009 range, as was the case for the Spanish Grand Prix earlier in the year.
Engine
Istanbul presents a varied workout for the engine, requiring both good top speed and low end performance. Turn Eight remains a constant concern where the engine is concerned as it is important to ensure effective power delivery at high revs for good performance in this high-speed corner. Overall around 65 percent of the lap is spent on full throttle, which is about average for the circuits on the calendar.

Monday, June 1, 2009

Why tyre size matters - Bridgestone explain

bridgestone2009small

As far as racing tyres are concerned, size does matter, particularly for this Formula One season, which has seen the return of slicks after an 11-seasons’ absence. The removal of the grooves which were previously on the tread area means that the proportional size of the rear tyres’ contact patch has changed relative to the fronts’.
“There are many differences between a slick and a grooved tyre, but the change of the proportional tread area in contact with the road is a very important aspect of the performance potential,” explains Hirohide Hamashima, Bridgestone’s director of motorsport tyre development. “This year we are hearing a lot of talk about weight distribution and the balance of the cars and this is related to the big changes to the regulations for the cars and the tyres for 2009.
“The latest aerodynamic regulations mean a lower and wider front wing, but a taller and narrower rear wing. This means the proportion of aerodynamic grip - the grip provided by the downforce pushing the car down onto the road - has moved towards the front of the car.
“In addition to this, there is more mechanical grip - grip provided by the tyres interacting with the road surface - than before at the front of the car, due to the proportionally bigger contact patch of the front tyre, so the latest cars have a lot more grip on the front than previously.”
The additional grip at the front means that the latest cars work their rear tyres harder than before.
“We can certainly say that the current generation car has an oversteer tendency, where the rear of the car doesn’t have as much grip as the front, and this tendency is a focus for teams in their car set-ups and designs,” explains Hamashima.
An oversteering car is generally one that is good at turning in to corners, but one where the rear of the car has trouble following the path of the front. In American terminology, the car is ‘loose,’ meaning the rear slides around. This is often fun to watch, and can result in the cars being spun, but it’s not necessarily the fastest way around a race track. So, if there’s more grip at the front than there is at the rear, surely it’s time for more grip at the rear?
“Of course, we could make more grip for the rear tyres through different rubber compounds or construction or wider tyres. However, we can’t make use of different rubber and wider tyres, because of the regulations. When we make use of different construction, however it is the front tyre which has too much grip rather than the rear tyres not having enough,” explains Hamashima.
“When we moved to grooved tyres for the 1998 season, the opposite was the problem, as the front tyres did not have enough grip. To counter this we made a taller and wider front tyre. When the rules were changed to allow slicks back we recommended that the tyre sizes were changed back to the sizes before grooves came in - with smaller front tyres - however the teams’ car designs were already very far advanced for the same size tyres as used with the grooved tyres.”
The size of the front tyre has a particular impact on a Formula One car’s aerodynamics. The front tyres present a large surface cross section to the airflow and cause a lot of drag, so a big factor in the design of the car’s bodywork and wings is trying to compensate for this.
For the future, Bridgestone has already tested a narrower front tyre and is working with the FIA and the teams regarding any potential change for the future.
“For Bridgestone we can make front tyres of the current size, or of a narrower width, so it is not a problem for us once a decision is made about the tyre size,” explains Hamashima. “The size is set in the regulations, so it is not a change we would make in isolation, it is something that if it happens it will be because there have been consultations between us, the FIA and also the teams.”
Bridgestone tested a smaller front tyre in Jerez in Spain back in March.
“The test in March, where eight teams were present, was useful for evaluating a potential new front tyre size by six teams,” explains Hamashima. “We went narrower on width, but based on what we learnt from running that tyre we would probably want to go a bit narrower still. For now, however, we have the excitement of the 2009 season.”

Redesigned mirror support on Brawn BGP001

Since Spain, Brawn is introducing updates all over its car, some smaller than others. At Monaco the BGP 001 featured updated mirror supports. Up to now, the team was running a twin element support while the new version is a much thicker aerofoil. Such in-season change of a previously simple element marks the team's search for performance improvement in areas where aerodynamic development is still allowed.

Thursday, May 21, 2009

Monaco - Formula One car set-up guide

Monaco may be the most unique race on the Formula One calendar, but for the engineers the challenge around the demanding street circuit remains the same: fine-tuning the car to achieve maximum performance. It's an unforgiving place, and getting the most from the R29 will require an unusual set-up and total commitment from the driver. As a street circuit, the track usually offers low grip in the early part of the weekend, but come Sunday it will be nicely rubbered-in and will continue to improve until the final lap of the Grand Prix. Renault explain how they plan to ready the R29...
Ride Heights
The roads in the principality may feel billiard-table-smooth at the wheel of a road car, but they are incredibly bumpy for the stiff suspension of a Formula One car. To cope with the variations in track surface, ride heights are raised between 5 and 7mm relative to the norm. The public roads are also sharply cambered and very slippery - especially on the traffic markings that are dotted around the circuit which require caution, especially if the track is damp.
Suspension
In order to maximise the car's grip, the team will use softer suspension settings than normal. This helps the car to ride the bumps and changes of camber. The surface also means that the wheels must be able to move independently to cope with the bumps and so we soften the anti-roll bars to achieve this. Special attention is paid to suspension camber angles too. The key objective is to give the driver a neutral, driveable car that he can have confidence in around the circuit, especially in the fast Massenet-Casino Square complex.
Renault driver Fernando Alonso explains: "The run through Massenet and Casino Square is one of the fastest parts of the lap. The first left- hander seems to go on forever and is quite bumpy so you have to be careful to balance the car on the throttle to avoid oversteer. You have to hug the barrier as much as possible to make a late apex and get online for the next right-hander which is a blind corner. The car becomes very light as there is a bump on the exit, but it's important to get on the throttle as early as possible for the approach to Mirabeau."
Aerodynamics
Monaco demands the highest downforce levels of the season. Contrary to popular belief, the primary benefit does not come in the corners, as many of them are taken at such low speeds that mechanical grip is of greater importance. Rather, the gains from high downforce come under braking and acceleration, keeping the car stable into the corners and ensuring optimum traction on the exit.
Driver Nelson Piquet explains: "The biggest braking zone on the circuit is the chicane of Turns 10 and 11. You come out of the tunnel, which is the fastest part of the lap in seventh gear and have to brake down to 70 km/h for the chicane. It's probably the best overtaking opportunity of the lap and you need good stability under braking."
Steering angle
The famous hairpin at the Grand Hotel is the tightest of the year - along with the sharp turn at Rascasse. Monaco therefore demands the highest steering angle of the season, some two times greater than anything required at the previous race in Barcelona. Dedicated Monaco front suspension is produced to ensure the necessary steering lock can be applied.
"The Grand Hotel hairpin is the tightest and slowest corner of the year,” said Alonso. “It's taken at under 50 km/h and requires full steering lock and is quite a technical corner. It's important to hit the apex so you don't lose too much time through this part of the lap."
Tyres
Previously this season the Bridgestone tyre compounds supplied to the teams have been two steps apart in terms of their characteristics. However, Monaco sees a change to this allocation philosophy due to the unique demands of the street circuit. Bridgestone will therefore bring the super-soft and soft compounds, which are well suited to working at lower temperatures.
Engine
Superficially, Monaco may seem the least demanding circuit of the year, with just 45 percent of the lap spent on full throttle. Appearances, though, do not reflect reality. The bumpy surface means the engine can easily over-rev if the wheels leave contact with the ground. A driveable engine and good traction from very low revs are extremely important.

Saturday, May 16, 2009

Aerodynamics explained – in detail

Aerodynamics is the science that studies objects moving through air.

It is closely related to fluid dynamics as air is considered a compressible fluid. Nowadays, aerodynamics is the utmost important factor in Formula One car performance. It has even nearly become one of the only aspects of performance gain due to the very marginal gains that can currently be made by engine changes or other mechanic component development. This downforce 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.

Furthermore, as Formula One teams have the greatest resources to develop aero efficiency of its cars, the greatest strives are made here. F1 teams have unrivalled CFD computing power and at least one full time wing tunnel, only for validating and improving their designs.

While basic aerodynamic methods and formulas can be simply resolved, other properties are verifiable with empirical formulas. More complex shapes such as airplanes or racing cars are however impossible to calculate precisely, rendering computational fluid dynamic systems (CFD applications on super computers) and wind tunnels an absolute requirement to validate designs.

 

 

 

 

 

Application in Formula One

F1 (and in general, all winged racing cars) 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 creating downforce.

From a spectator's point of view, a car can be considered in (at least) 3 parts: the front wing, the car's body and the rear wing. Each of the parts can be optimised for the required downforce at a minimum of drag. Practically however, every component has its influence on the behaviour of the car and cannot be regarded as an individual component. As a result, no element is tested individually, but always a complete scale model of a car.

Because a complete racing car is a very complex system, teams of engineers usually evolve the car step by step, developing a particular item and check its effect on the car. Such overall effect can then be calculated with "Amdahl's law":

Here is the fraction of the system (when this fraction generates 5% of the car's drag, then is 0.05) that can be improved, is the improvement factor on this fraction (division of the drag in Newtons and the new drag force after improving that element), and is the overall improvement that will be achieved.

After verifying its improvement, the car's efficiency is determined and then simulated on different tracks to see on where it is useful. That usefulness is always the result of a reduction in drag or an increase in downforce.

Drag

Drag is the aerodynamic force that is opposite to the velocity of an object moving through air (or any other fluid). Its size is proportional to the speed differential between the air and the solid object. It is therefore unimportant if either the air is moving around a static object or if the object is moving at a speed through static air.

Drag comes in various forms, one of them being friction drag which is the result of the friction of the solid molecules against air molecules in their neighbourhood. Friction and its drag depend on both the fluid and the solid properties. A smooth surface of the solid for example produces less skin friction compared to a rough one. For the fluid, the friction varies along with its viscosity and the relative magnitude of the viscous forces to the motion of the flow, expressed as the Reynolds number. Along the solid surface, a boundary layer of low energy flow is generated and the magnitude of the skin friction depends on conditions in the boundary layer.

Additionally, drag is a form of resistance from the air against the solid moving object. This form of drag is dependent on the particular shape of a wing, and is therefore called form drag. As air flows around a body, the local velocity and pressure are changed, effectively creating a force.

Interference drag or induced drag on the other hand is the result of vortices that are generated behind the solid object. Due to the change of direction of air around the wing, a vortex is created where the airflow meets unchanged, straight flow. The size of the vortex, and thereby its drag strength increases with an increasing angle of attack of the aerofoil. As a primary source of possible drag reduction, Formula One teams try to counteract this drag by adding end plates to wings or with fillets at the suspension arms.

Other sources of drag include wave drag and ram drag. The first is unimportant for normal racecars as it occurs when the moving object speeds up to the speed of sound. Ram drag on the other hand is the result of slowing down the free airstream, as in an air inlet.

The amount of drag that a certain object generates in an airflow is quantified in a drag coëfficient. This coëfficient expresses the ratio of the drag force to the force produced by the dynamic pressure times the area. Therefore, a of 1 denotes that all air flowing onto the object will be stopped, while a theoretical 0 is a perfectly clean air stream.

At relatively high speeds, ie. at high Reynolds number (), the aerodynamic drag force can be calculated by this formula:

where is the force of drag (in Newton), the density of the air, the speed of the object relative to the fluid (in m/s), the reference surface and the coëfficient of drag. Note the minus sign and the vector which indicate that the resulting drag force is opposite to the movement of the object.

Downforce

Aerofoils 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 aerofoils to what they are now is mainly thanks to the genious and research of a few well known scientists. In 1686, Sir Isaac Newton presented his three laws of motion, one of them being the conservation of energy. He stated that energy is constant in a closed system, although it can be converted from one type to another. Out of that theory, Daniel Bernouilli deducted a formula proving that the total energy in a steadily flowing fluid system is a constant along the flow path. An increase in the fluid’s speed must therefore be matched by a decrease in its pressure. Adding up the pressure variation times the area around the entire body determines the aerodynamic force on the body.

An aerofoil's operation can be easily explained when you consider a wing in a steady, laminar flow of air. As air is a gas, its molecules are free to move around and may have a different speed at different locations in the airstream. As downforce generating aerofoils are mostly designed with more thickness on the lower side, the lower airstream is slightly reduced in surface, hence increasing the flow speed and decreasing the pressure. On top of the wing, the airspeed is lower, and thus the pressure difference will generate a downward force on the wing. Additionally, and in line with Newton's third law of motion, downforce wings are never straight and induce a new turning of the airflow. More specifically, the shape of the wing will turn air upwards and change its velocity. Such speed creates a net force on the body.

This shows that a force causes a change in velocity , or also, a change in velocity generates a force. Note that a velocity is a vectorial unit, having a speed and a direction component. So, to change of either of these components, you must impose a force. And if either the speed or the direction of a flow is changed, a force is generated.

It is very important to note that the turning of the fluid occurs because the molecules of the fluid stay in contact with the solid body since the molecules are free to move. Any part of the solid body can deflect a flow. Parts facing the oncoming flow are said to be windward, and parts facing away from the flow are said to be leeward. Both windward and leeward parts deflect a flow.

Downforce is however often explained by the "equal transit time" or "longer path" theory, stating that particles that split ahead of the aerofoil will join together behind it. In reality however, the air on the longer side of the wing will flow much faster, further increasing the downforce effect.

While these simplified versions are the basics of lift and downforce generation, the reality can hardly be simplified and is a complex study, requiring high power computer systems. For a gas, we have to simultaneously conserve the mass, momentum, and energy in the flow. Hence, a change in the velocity of a gas in one direction results in a change in the velocity of the gas in a direction perpendicular to the original change. The simultaneous conservation of mass, momentum, and energy of a fluid (while neglecting the effects of air viscosity) are called the Euler Equations after Leonard Euler. Several computer algorithms are based on these equations to make an approximation of the real situation.

Because of the complexity, today's Formula One cars are designed with CFD (computational fluid dynamics) and CAD (computer aided design) that allows engineers to design a car, and immediately simulate the airflow around it, incorporating environmental parameters like traction, wind speed and direction, and much more.

Wednesday, May 13, 2009

Ferrari revert to complex front endplates

There was a time when Ferrari was known for its complicated front wing endplates, and steadily it looks like that is coming back. The team however is now only a follower as they copy various design properties of other, faster cars.
The endplate has complicated since the car's first race. An additional vertical element was added, very similar to the Brawn BGP001. Slightly hidden is a small slot that catches air and directs it inwards of the end plate. Additionally the wing itself now has a higher curve close to the end plate, something that was also copied from Toyota.

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Tuesday, May 12, 2009

Aero updates for Brawn BGP001

Brawn have introduced their first car updates at the Spanish GP, keeping them ahead of the competition. One of the changes includes a redesigned engine cover. While the previous design was a smooth cover, the new updated sidepods have a sharper inward curve. More in the centre of the car, following the exhausts is a new cover of the suspension components.
Marked with a second arrow is also the slightly modified bodywork ahead of the exhaust openings, somehow resembling the curved sidepods of the Force India VJM02.

 

Monday, May 11, 2009

Formula 1 teams - aero upgrades seen in Spain

Aerodynamic updates are abundant at the Spanish Grand Prix

Pretty much every team on the Formula 1 grid has brought a major update to Barcelona for the Spanish Grand Prix. Some are clearly working, others are not working so well. When asked if the updated McLaren MP4/24 was improved driver Lewis Hamilton gave a clear answer to the BBC: "No." McLaren had one of the more minor update packages in Spain as it has focussed on introducing small updates at each race rather than large major updates. Brawn GP brought its BGP001's fitted with a new floor, engine cover, and bodywork around the rear suspension.

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Renault had a similar update kit as Pat Symonds explains "as we have said earlier we introduced our first double decker diffuser in China but it was very much our first attempt. There is a new attempt here. In addition, with visible parts, we have got new front wheel fairings, we have got a new top rear wing here. We have got modifications on rear suspension, so there is a lot going on."

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The biggest update of all was seen on the BMW-Sauber F1.09,  The nose, side pods and the rear wing are completely new, while the front wing, the engine cover and the diffuser have been modified. This has given the car a strange new look which has already enhanced usage of the cars 'ugly' tag. 

Friday, May 8, 2009

Barcelona's Circuit de Catalunya - an F1 set-up guide

The Spanish Grand Prix circuit near Barcelona is one that every Formula One team knows well from the hundreds of kilometres of testing carried out there over the winter. Few venues offer such a variety of medium and high-speed corners and it is widely acknowledged as the definitive aero circuit that provides a stern test of a car. With few big braking zones and so many high-speed corners, overtaking is extremely difficult and a good qualifying performance and sensible strategy are paramount for a successful weekend. Renault explain how they plan to ready the R29 for racing…

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Aerodynamics:
Aerodynamic efficiency is always a key factor at Barcelona, although the introduction of the chicane at the end of the lap in recent years has replaced on of the most critical high-speed parts of the lap and means the track is not as demanding as it once was. Even so, the circuit remains the ultimate test of a car's aero package and teams will run with high downforce levels to ensure competitiveness over the whole lap.
Renault driver Fernando Alonso explains: "There are lots of high-speed corners where good aero performance is critical. A good example is Turn Nine, a fast right hand corner taken in fifth gear at about 230km/h. You have to be very precise with the car as there is there is no room for error on the exit and it's important to carry good speed onto the back straight."
Suspension:
With the suspension we have to find the best compromise to give the drivers a well balanced and responsive car. This means we will use relatively stiff settings at the front of the car to get a good change of direction, while the rear will be slightly softer in order to get the best possible traction out of the slower corners, such as Turns 14 and 15.
Ride height is also an important parameter to consider as generally we can run the car quite low in order to gain maximum aerodynamic performance.

Engine Performance:

Barcelona is not generally thought of as an 'engine circuit' as the engine is not under particular stress as any point and only 61 percent of the lap is spent on full throttle. There are relatively few hard acceleration zones from low revs as the engine spends most of the lap accelerating from the middle of the rev range. As such, the priority is for the power delivery to be progressive and driveable in order to maintain the best handling balance, and limit tyre wear.

Tyres:

Barcelona is well known for being demanding on tyre wear because it includes so many long, high-speed corners and has a fairly abrasive track surface. The most demanding corner is perhaps Turn Three.

The tyres are therefore under high loadings, particularly the front left which has to work hard through Turn Three as well as Turn Nine. As a result Bridgestone will supply the hard and soft compounds this weekend, and the team will need to pay close attention to the wear and degradation during free practice to determine which compound to use for the majority of the race.

Wednesday, May 6, 2009

Force India, more upgrades but no KERS yet

Force India will add more modifications to their car for this weekend’s Spanish Grand Prix, but have put off introducing KERS until later in the season, choosing instead to focus on the VJM02’s aerodynamics.

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The team were pleasantly surprised by the performance gains obtained from a new diffuser and aero upgrades at the last round in Bahrain and further revisions for Barcelona could boost their competitiveness still further.
“We'll have yet more upgrades coming through based on the information we gained in Bahrain,” confirmed team principal Vijay Mallya. “We'll be running a driver-adjustable front wing flap and a further modification for the front wing. This is just part of our ongoing development cycle and there will be further upgrades at most of the forthcoming races.”
The Spanish Grand Prix had also been pencilled in as the race where Force India would add KERS to their armoury. However, after witnessing the mixed fortunes experienced by those teams running the system, Mallya says Force India will concentrate their efforts elsewhere for now.
“We have decided to put the emphasis on aero development where we feel the greater gains can be found,” he said. “As we've seen many other teams are not running KERS so we do not feel we are at a disadvantage. We still plan to use it later in the season, but this will be reviewed after each race in line with the other work we have going on in the background.”
Though world championship points have still eluded them, Force India have clinched a top-ten finish in 2009 - Adrian Sutil took ninth in Australia - and Mallya admitted their pace has exceeded his expectations.
“We always said that the first four flyaway races would be extended test sessions and we have indeed used them wisely,” he said. “We've accustomed ourselves to the new systems, new personnel and new ways of working and introduced some very worthwhile upgrades.

Monday, May 4, 2009

FIA reveals Formula 1 2010 regulations

Refuelling ban, and other cost limitation measures

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Formula 1 will not feature refuelling pit stops next year after the FIA revealed a number of changes to both the technical and sporting regulations. Many of the changes are aimed at reducing team budgets such as the introduction of a slightly different set of rules for cost regulated teams.

The ban on refuelling is also aimed at keeping costs under control, allowing teams to leave the large and weighty fuel rigs at home and thus save on freight.  This will have a major influence on race strategy as tyres will now define everything, fuel efficiency will also be critical. Notably the cars will also be 15kg heavier with an increased minimum weight of 620kg. Tyre warmers have been outlawed, meaning very few series now permit them at all, it seems likely that they will fall out of use entirely in the next few years

F1 KERS has undergone some notable changes, its usage is no longer permitted when the car is travelling at over 300kph, and all the storage devices must be situated between the front face of the engine and the driver's back when viewed in lateral projection. A brake valve can also be fitted to the energy recovery system which can reduce the pressure generated by the driver in the rear brake circuit during KERS operation.

With such major changes the teams now have a scramble to lodge entries by 29th May, the €309,000 entry fee to be payable on 1 November 2009.

Saturday, May 2, 2009

BMW pins hopes on upgrade package

BMW Sauber expects a 'significant' improvement in its pace when it introduces a swathe of upgrades for the Spanish Grand Prix, but with so many of its rivals doing likewise, the team is unsure whether its development efforts will pay off.

Technical director Willy Rampf explained that major aerodynamic changes were on the cards as last year's third-best team tried to get out of its current lower midfield position.

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"The nose section, more deeply undercut sidepods and the rear wing are all totally new," he said.

"Added to which, modifications have also been made to the front wing, engine cover and underbody. We expect these improvements to significantly reduce our lap times.

"Of course, we know that the other teams will also have made modifications to their cars for Barcelona.

"However, we expect to be able to close the gap to our rivals.

"We won't find this out for certain, though, until the race weekend.

"Up to then we will only have the results from the wind tunnel and simulations to go on and, of course, can no longer test in advance on the track."

Team boss Mario Theissen admitted that BMW's very poor start to 2009 had been tough to take.

"We cannot be satisfied at all with the first four races of the season," he said.

"After our positive winter testing, all of us at the BMW Sauber F1 team envisaged a rather different start to the season.

"The car is not fast enough and we have recorded only one podium finish.

"We are approaching this challenge in a positive way and are working intensively in Munich and Hinwil to get back to our old form.

"We will be lining up in Barcelona with an extensive aerodynamics-focused development package, and are already working on further upgrades to be introduced later on in the season."

Tuesday, April 28, 2009

F1 to run narrow front tyres next year

Bridgestone trial new rubber to improve car balance

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This season sees the return of slicks after eleven seasons’ absence from F1 and the removal of the grooves which were previously on the tread area of the tyre means that the proportional size of the contact patch of the tyres from the front to the rear has changed. “There are many differences between a slick and a grooved tyre, but the change of the proportional tread area in contact with the road is a very important aspect of the performance potential,” explains Hirohide Hamashima, Bridgestone Director of Motorsport Tyre Development. This year we are hearing a lot of talk about weight distribution and the balance of the cars and this is related to the big changes to the regulations for the cars and the tyres for 2009. “The latest aerodynamic regulations mean a lower and wider front wing, but a taller and narrower rear wing. This means the proportion of aerodynamic grip – the grip provided by the downforce pushing the car down onto the road – has moved towards the front of the car. “In addition to this, there is more mechanical grip – grip provided by the tyres interacting with the road surface - than before at the front of the car, due to the proportionally bigger contact patch of the front tyre, so the latest cars have a lot more grip on the front than previously.” The additional grip at the front means that the latest cars work their rear tyres harder than before. “We can certainly say that the current generation car has an oversteer tendency, where the rear of the car doesn’t have as much grip as the front, and this tendency is a focus for teams in their car set-ups and designs,” explains Hamashima. An oversteering car is generally one that is good at turning in to corners, but one where the rear of the car has trouble following the path of the front. In American terminology, the car is ‘loose’ meaning the rear slides around. This is often fun to watch, and can result in the cars being spun, but it’s not necessarily the fastest way around a race track. So, if there’s more grip at the front than there is at the rear, surely it’s time for more grip at the rear? “Of course, we could make more grip for the rear tyres through different rubber compounds or  construction or wider tyres. However, we can’t make use of different rubber and wider tyres, because of the regulations. When we make use of different construction, however it is the front tyre which has too much grip rather than the rear tyres not having enough,” explains Hamashima “When we moved to grooved tyres for the 1998 season, the opposite was the problem, as the front tyres did not have enough grip. To counter this we made a taller and wider front tyre. When the rules were changed to allow slicks back we recommended that the tyre sizes were changed back to the sizes before grooves came in – with smaller front tyres - however the teams’ car designs were already very far advanced for the same size tyres as used with the grooved tyres.” The size of the front tyre has a particular impact on a Formula One car’s aerodynamics. The front tyres present a large surface cross section to the airflow and cause a lot of drag, so a big factor in the design of the car’s bodywork and wings is trying to compensate for this.  For the future, Bridgestone has already tested a narrower front tyre and is working with the FIA and the teams regarding any potential change for the future. “For Bridgestone we can make front tyres of the current size, or of a narrower width, so it is not a problem for us once a decision is made about the tyre size,” explains Hamashima. “The size is set in the regulations, so it is not a change we would make in isolation, it is something that if it happens it will be because there have been consultations between us, the FIA and also the teams.”Bridgestone tested a smaller front tyre in Jerez in March. “The test in March, where eight teams were present, was useful for evaluating a potential new front tyre size by six teams,” explains Hamashima. “We went narrower on width, but based on what we learnt from running that tyre we would probably want to go a bit narrower still “For now, however, we have the excitement of the 2009 season. After the season has ended we will test the tyres for 2010, but we expect to make a decision before too long.”

Sunday, April 26, 2009

F1 aerodynamic modifications on display in Bahrain

Force India and McLaren introduce new bodywork

More and more teams are treating the practice sessions on Friday as open testing. Using them to develop new parts rather than to find the best setup.

McLaren introduced a few updates at Sakhir, most notably a new asymmetric exhaust exit configuration. The left hand outlet is larger than the right as the left hand sidepod contains extra heat exchangers.A more extreme version was tested n Friday but the race spec variant (below) is less radical.

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Force India also introduced a major new aero package for the VJM02 featuring a new floor, front wing end plates, diffuser and revised side pods

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Renault adjusted the R29's exhaust exits and cooling on the engine cover.

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Saturday, April 25, 2009

Renault revises sidepods for Bahrain

Renault have been very quick introducing new bits on its R29 contender, and part of their rear end update at China was a heavily revised sidepod ending. In sharp contrast with version seen at the launch, the new sidepods have more openings to provide extra cooling. As such the team could slim down the bodywork quite a bit and ditch its undercut hot air channel between the rear wheels.

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A disadvantage of allowing more hot air to escape earlier on in the air stream, the sidepod components are exposed to much more heat. After initial running at Bahrain today, the team decided to fit additional titanium plates close to the exhaust to prevent the bodywork from burning.

Wednesday, April 22, 2009

New floor and diffuser for Force India in Bahrain

Force India are making major revisions to their car for this weekend’s Bahrain Grand Prix, as the team continue the search for their first Formula One points. A revised floor and diffuser will be among the changes debuting on the VJM02 at Sakhir.
Drivers Adrian Sutil and Giancarlo Fisichella have shown some promising pace in the opening three rounds of 2009 and team principal Vijay Mallya hopes the latest updates to their Mercedes-powered machine will keep them in touch with the rest of the field.
“We are planning to introduce a significant aerodynamic upgrade for the Bahrain Grand Prix, including a new floor and an interim diffuser,” Mallya confirmed. “Amongst other items, we also plan to use new auxiliary wings on the front wing and reprofiled sidepods to incorporate the amended rear end.”
The changes are not merely a response to the recent double-decker diffuser ruling, but have been planned by the team since the VJM02’s debut (at the end of February) as part of their aerodynamic development programme. “It will represent a good step forward for the team,” added Mallya.
Sutil is the man who has come closest to taking Force India’s maiden points. He finished ninth in Melbourne and was running as high as sixth in China last weekend before crashing out with less than six laps to go. The German has high hopes for the Sakhir updates, but admits scoring might still be a big ask.
“The new parts we have coming through for this race should keep us close to the others and I hope we will be able to have a good, competitive race,” said the German. “The goals for Bahrain are really going to be the same as for China. For sure I want to finish the job, but I think getting points here will be very difficult.”
Fisichella, meanwhile, believes the Force India package is basically sound and hopes the latest revisions to the car will help address its one major failing - an overall lack of downforce.
“Mechanically the VJM02 is good,” he said. “It feels quite balanced and consistent and is a big improvement from last year. We’re working well with the new team partners, McLaren and Mercedes, and I think we have a lot we can be positive about.
“We know where we need to improve: we are missing a lot of downforce and it shows, but now we have started to introduce new upgrades I am hopeful we can start to fix this problem.”

Tuesday, April 21, 2009

Newey: No double diffuser until Monaco

Red Bull's technical boss Adrian Newey has ruled out the introduction of a double-decker diffuser in the team's race-winning RB5 before the Monaco Grand Prix next month.

The Renault-powered car, driven by Sebastien Vettel, gave Red Bull Racing its maiden Formula 1 victory at last weekend's Chinese Grand Prix.

Vettel's team-mate Mark Webber finished in second as a car not fitted with a double-decker diffuser won a race for the first time this year.

Newey, however, decided not to travel to China in order to focus on the new floor, but he admits it will be a challenge to make it work properly given the car's rear suspension design.

"As has been speculated, given the design of RB5, it's not the easiest task getting it to fit the car and while we work on this one item, we also need to keep working on the general development of the car, to ensure we don't fall behind in other areas," said Newey.

"The unique feature of the Red Bull cars is the pullrod rear suspension, which is a good solution when you don't have a double-diffuser. But getting it to work with the diffuser will be more difficult. We won't have a double-diffuser before Monaco.

"It will certainly involve a lot of work," he added. "The challenge now is to try and integrate the new diffuser into the rest of the car. But I don't regard it as a shame, I see it as another challenge.

"Unfortunately, it will involve some more late nights! That's Formula One: you can't afford to sit around and feel sorry for yourself, you just have to get on with it.

"There is no doubt that a double-diffuser does give performance. How much performance depends on how you interpret the regulations and how you adapt it to suit your own car, so that some teams will get more out of it than others. It is worth doing for everyone on the grid. Our challenge is to adapt one to work on our car."

Monday, April 20, 2009

A new front wing for Alonso's Renault R29

Apart from a whole range of changes on the rear end of the car, Renault have also changed their front wing to be more efficient. The above detail image is the new Shangai version for Alonso, while the lower one is that used in the 2 earlier races and by Piquet at Shangai. The latter will undoubtedly soon also have this update once the team finish manufacturing of a second one.
Marked by the arrows is the trailing edge of the main flap, now featuring sharp cuts and a more elaborate gurney flap - the latter painted white as of Saturday's free practice.

Sunday, April 19, 2009

Formula 1 teams revise bodywork in China

Formula One teams often wait until the first European race of any given season before introducing major updates, but in the wake of the FIA World Council descision on diffusers earlier this week a number of teams have new parts on the cars. Most notably McLaren.








The car also features an 'interim' diffuser which is a step towards the Brawn GP, Williams and Toyota solution, which is estimated to give those cars an extra 5% in downforce. The McLaren exhaust outlets were also revised.








Meanwhile Ferrari has fitted the F60 with McLaren style 'arrowhead' wheel covers. With an iteresting cut out dropping down from the 'point' of the cover.

Scuderia Toro Rosso has been experimenting with the front wing, for the first time testing the moveable elements. Not the white 'I-pod' wires running down to the actuators on the endplates. Most teams run the wires through the wing supports