All posts by John Beamer

Felipe Massa, Ferrari, Melbourne, 2012

The problems with Ferrari’s front pull-rod suspension

Felipe Massa, Ferrari, Melbourne, 2012Before the Malaysian Grand Prix the internet was awash with rumours Ferrari will introduce a B-spec car in the May test at Mugello.

We’ve heard similar claims in recent years when Ferrari have faltered early in the season. But despite Fernando Alonso’s surprise win in Malaysia it’s clear they have significant problems with the F2012.

Much attention has been focussed on its pull-rod front suspension. Last year most teams followed Red Bull’s lead in adopting pull-rod suspension at the rear of the car but Ferrari did not.

This year as well as using pull-rod suspension at the rear of their car, Ferrari have become the only team to use it at the front of the car.

The car has looked a handful to drive and was well over a second per lap off the pace in the dry in Sepang.

It’s doubtful this deficit is coming from a single area. It appears the exhaust position on their current car ?ǣ the so-called ‘Acer ducts’ ?ǣ needs to be changed in order to better seal the diffuser.

Ferrari will likely move the exhausts forward to allow more space to shape the airflow towards the floor. This would mean a change to the side-impact structure and therefore a new crash test.

The other question mark surrounds the front pull-rod suspension. Will the Scuderia persist with the system or abandon it in favour of a more traditional push-rod system?

In this short article we?ll examine the difference between the pull- and push-rod systems and how likely it is that Ferrari will make the switch back to push-rod.

The basics of suspension in an F1 car

An F1 car has a very small degree of suspension travel compared to a road car. Its purposes are not just to make the car ride well over bumps, but to improve traction and aid aerodynamic performance.

The suspension controls for bumps on the track and roll when cornering, both which affect the handling of the car. This is very complex as there are many dimensions to the car’s motion, as we’ll see later.

Suspension plays a vital role in managing aerodynamics. If a constant ride height can be maintained the car’s aerodynamics work better.

Also the suspension arms and wishbones can act to manage airflow downstream. Packaging is also important ?ǣ the primary benefit of the rear pull rod was to reduce the centre of gravity (CoG) of the car (which we?ll see when we examine the front pull-rod in detail) and to create more space in the coke bottle zone to maximise airflow over the diffuser.

How push-rod suspension works

Ferrari's front pull-rod suspension image 1Most teams use a push-rod suspension system similar to that shown in the first illustration at the front of their cars.

The suspension arm, coloured blue, connects from the lower part of the wheel upright to a rocker located in the top-part of the chassis. The rocker connects the push-rod to a torsion bar and damper which manages ‘bump’ – i.e. the up and down movement of a wheel. The torsion bar is basically a spring but is twisted rather than compressed.

In addition there is an anti-roll bar which links the suspension across the chassis to control the degree of roll. This redistributes weight to the inside tyre, which helps traction. If you make the bar too stiff then when one wheel goes into bump the other follows and the car feels very unstable.

The final components are the inerter and heave spring. The heave spring manages vertical movement ?ǣ i.e., when both wheels rise or fall together. Lastly the inter is a very subtle component and is tuned to the natural frequency of the tyres and translates the oscillating motion of the rubber into rotational energy ?ǣ it is a spinning mass on a threaded bar ?ǣ again to improve traction.

Of course, not all the bump absorption takes place in the suspension: Wheel rubber flex accounts for around 30% of this total movement in an F1 car.

Pull-rod versus push-rod suspension

Ferrari's front pull-rod suspension image 2The next illustration shows a pull-rod set-up. The components and function are the same.

There are two differences: the suspension arm is connected from the top of the upright to the bottom of the chassis, and the internal components are lower in the chassis.

This set-up has two advantages over the push-rod. By placing the suspension components closer to the ground the centre of gravity is lower. Also the suspension arm is better able to condition airflow from the front wing towards the sidepod so in theory there is a small aerodynamic gain.

However, the chassis shape is constrained by FIA guidelines so the aero gain is not as great as it is when pull-rod suspension is used at the rear of the car.

There are two main disadvantages to front pull-rod suspension. One is that the the upper wishbone must transmit more load, some of which would otherwise have been carried by the push-rod. This means the chassis and wishbone needs to be strengthened ?ǣ see the yellow circle. This adds weight and negates somewhat the CoG gain.

The second disadvantage is it takes longer tune a pull-rod. This is important given the limited testing time in F1 today. Teams need to rapidly tune spring and damper settings and if the components are hidden away this is trickier and potentially reduces valuable track time.

Ferrari's front pull-rod suspension image 3In summary the net benefit of switching to a pull-rod is a (very) small aero gain at the expense of tuning simplicity. The final illustration shows the pull-rod and push-rod side-by-side and the difference in geometry and CoG are apparent.

However, Gary Anderson raised an interesting point in Autosport that may further comprise the front pull-rod set-up.

By connecting the push-rod to the wheel upright the driver can use steering angle to affect the suspension. Under steering the natural movement of the push-rod reduce load transfer across the chassis and effectively allows a softer set-up.

The opposite happens with a front pull-rod so it is connected to the wishbone rather than the upright to counter this effect. Hence all else being equal you need to run a stiffer suspension set-up which compromises mechanical grip.

In short, Anderson?s assertion is that the pull-rod also has mechanical compromises that more than offset the (small) aero gains.

Without having access to a dynamo data and proper car models, quantifying the effect is difficult. But the logic appears sound. There is no doubt that when Red Bull introduced the rear pull-rod with success teams will have evaluated a front pull-rod set-up as well. That only one team has adopted it suggests if there is a gain it likely is not worth the hassle.

What’s next for Ferrari?

Will Ferrari make the switch back to push-rod this year? Personally I don?t think so as it would be a massive admission of failure and the gain either way is minimal.

More likely is a switch back to push-rod for the 2013 car, unless the aero gains become more apparent in the re-design. Ferrari’s win in Malaysia makes things a little more interesting as the supposed mechanically disadvantaged pull-rod should not in theory yield benefit on a slippery surface.

However, the story of Ferrari?s victory (notwithstanding the tremendous efforts of Fernando Alonso) is in its ability to switch on the tyres in damp conditions better that its competitors, something which the Sauber appears even more adept at.

Their decision may be influenced by a desire to accommodate a Mercedes-style DRS-activated F-duct. Or that might serve as a useful excuse for abandoning the pull-rod set-up at the front of the car.

Ferrari are pinning their hopes on their May upgrade. Even if the updated packages works the Scuderia will struggle to catch up with McLaren and Red Bull as those teams have three months of experience in optimising the 2012 package and Ferrari will be starting from scratch.

Already the scene is set for a fascinating three days of testing in Ferrari’s backyard at Mugello in two months’ time.

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Image ?? Ferrari spa/Ercole Colombo, illustrations ?? John Beaner for F1 Fanatic

Red Bull RB8 exhaust diagram

How the Red Bull RB8′s exhaust feeds its diffuser

To no-one’s surprise the race-specification exhaust for the Red Bull RB8 appeared on the penultimate day of the last pre-season test.

The team went to considerable lengths to cover it up, as the video above shows. But now the design has been seen we can get a look at how it works.

As the FIA has restricted where teams can place their exhausts, designers are striving to continue using the hot air to make their diffusers more powerful.

Red Bull’s approach is similar in principle to McLaren’s exhaust concept in that it tries to pull the exhaust plume downwards from the exhaust exit over the side of the diffuser to create a sealing effect.

The Red Bull design appears quite different and more elegant. But we won?t know until Melbourne whether it is more effective.

The Red Bull RB8 exhaust

Red Bull RB8 exhaust diagram
Red Bull RB8 exhaust diagram
The first illustration shows Red Bull?s new set-up. I?ve left out the pull-rod suspension arm and lower wishbones to make the image a little clearer.

The grey zone where the exhaust exits is covered in heat-resistant paint to prevent damage to the carbon fibre. The exit contains a channel indent to drag the plume downwards using the Coanda effect, as described in the McLaren exhaust article.

This area is shaped to continue to drag the exhaust gas downwards towards the diffuser. In addition, air coming over the sidepod is also used to create a high pressure zone around the exhaust exit, further helping the Coanda effect and shaping the exhaust plume. The red lines show the exhaust flow.

The issue designers face is that this potentially interferes with how the undercut sidepod works.

Over the past couple of years teams have aggressively undercut the sidepod to feed fast-flowing air to the coke bottle zone. This helps the diffuser to be more effective by creating a low pressure zone above it, which in turn reduces flow separation in the diffuser.

Dragging the exhaust plume to the floor will reduce the effectiveness of the coke bottle zone. The bulge in McLaren’s exhausts is designed to direct the exhaust gas over this flow.

Red Bull have adopted a different solution which is visible in the image. They have carved a duct at the bottom of the sidepod for the undercut airflow to go through. This duct exits in the coke bottle zone, missing the exhaust plume.

Replicating the exhaust-blown diffuser effect

Red Bull RB8 exhaust diagram
Red Bull RB8 exhaust diagram
The second illustration shows a similar picture of the RB8′s exhausts in plan view.

The exhaust exit is circled in yellow and again I’ve added the exhaust flow (red) and undercut flow (blue).

From this angle it is possible to see the shape of the exhaust indent in the bodywork. It is built in such a way that the exhaust gas appears to split – one stream spills over the side towards a vane on the floor ahead of the inner part of the rear tyre.

This will create a vortex and is primarily aimed at sealing the diffuser – this part replicates the effect of last year’s exhaust blown diffuser.

The second stream adds energy over the diffuser, which will help reduce the pressure gradient above the diffuser exit and hence reduce the risk of airflow separation under the car.

It is thought by some that the exhaust flow may partly feed a duct in the floor that houses the starter motor hole. However, it is unclear at this point whether this is for exhaust gasses or air flowing through the sidepod duct. Given the restrictions on starter motor hole size the effect is likely to be small.

As exhaust solutions are developed we’ll get a feel for the most effective solution. Last year teams quickly converged on Red Bull?s solution to optimise the exhaust blown diffuser.

Ferrari technical director Pat Fry suggested the same could happen again this year, assuming Red Bull’s design is considered legal, telling Sky: “It comes down to what re-ingested exhaust gas is really and that’s a question for Charlie [Whiting].

“I think it’s the obvious direction to go in. We gave it a shot; we didn’t quite get it right. The issues we had, we weren’t going to solve for at least the first four races, so that’s why we had to back up and change course.”

At this point the Red Bull solution is visually neater but doesn?t completely eliminate the exhaust/undercut interaction. McLaren?s solution likely does a better job in this respect but could face trade-offs on drag or quality of exhaust flow to the diffuser. The first weekend of running in Melbourne will yield more clues.

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Illustrations ?? John Beamer for F1 Fanatic

Michael Schumacher, Mercedes, Barcelona, 2012

Front wing design case study: Mercedes W03

Michael Schumacher, Mercedes, Barcelona, 2012
Mercedes' front wing as seen at the last test in Barcelona

John Beamer takes a look at current trends in front wing design in F1 using the Mercedes W03.

Since the introduction of the 2009 technical rules, which closed off several areas for aerodynamic development, front wings have become one of the most important areas of car development.

This is because there are few other areas where designers have much freedom. Later rule changes have further limited the scope for improvements to the diffusers.

The front wing is a vital component because it is where the passing air first meets the car. The entire aerodynamic performance of an F1 car can be changed by the subtlest of alterations in front wing design.

The 2009 front wing

BMW 2009 front wing
BMW 2009 front wing

Cast your mind back to late 2008 when BMW ran the first 2009-specification car in an end of season test (see illustration above).

This one one of the first examples of post-2009 front wing design we saw. It was simple and boxy, with very square endplates which had the single function of pushing air around the front tyres.

The wing itself was a simple three-element device with none of the cascades or appendages we are now familiar with. (The 2009 rules also allowed it to be adjusted while the car was moving, but this rule was scrapped at the end of 2010).

Other teams followed with more refined concepts. Designers quickly realised a lot of lap time was available from a properly developed front wing. Outside of the FIA-mandated horizontal section below the nose there are comparatively few restrictions on what they can build.

This has resulted in an aerodynamic arms race that saw even midfield teams bringing updated front wings to every race.

The modern front wing – Mercedes W03

Mercedes 2012 front wing design (1)
Mercedes 2012 front wing design (1)

Fast-forward to the start of the 2012 season. This illustration shows the launch-spec front wing on the Mercedes W03.

Like the original BMW wing it has three element, but the similarities pretty much end there. It doesn?t take a trained eye to see how much more complex wing design has become in the space of just over three years.

The endplate structure is very intricate. It consists of multiple fins, some of which blend into the front wing elements.

There are a complex series of stacked cascades around the outer part of the wing. And there are further ‘indents’ across the leading edge and under-surface of the main plane. The Mercedes’ nose is thin, rounded and raised.

The modern philosophy of front wing design is that the device itself isn’t necessarily to create a ton of downforce but rather to condition the flow over the rest of the car. By manipulating how air leaves the front wing the flow to the tea-tray, sidepods, floor and diffuser can be optimised.

Nearly all teams use a three-element design such as this. Although a two-element design gives greater peak downforce, airflow separation on the underside of the elements is more of a problem and this compromises airflow to the rest of the car.

Mercedes 2012 front wing design (2)
Mercedes 2012 front wing design (2)

The second illustration shows the aerodynamic elements aft of the front wing (but not the suspension) ?ǣ the undernose vanes, bargeboard and detail around the leading edge of the floor.

From this angle you can start to appreciate why the front wing needs to be so detailed to create the right flow environment for the rest of the car to work.

Mercedes 2012 front wing design (3)
Mercedes 2012 front wing design (3)

Add in the suspension arms, steering rack and brake ducts and the picture is even more complicated as shown in the third illustration.

Brake ducts are also relatively free from regulation and is a hotbed of development. The W03 brake duct has a simple aerofoil below the duct.

Don?t be surprised to see this area developed further as the car mature. The suspension arms are also faired for aerodynamic benefit and manage flow around the sidepods. However the steep angle of the wishbones means the effect is small.

Mercedes 2012 front wing design (4)
Mercedes 2012 front wing design (4)

The final illustration selectively indicates airflow streams generated by the front wing.

This is a not a complete picture, but it gives an idea of how various vortices are created. The inner cascade is a perfect example: the air above the cascade is at a higher pressure than the air below it.

This higher pressure air will ??roll? towards the low pressure zone to equalize this lateral pressure gradient, and it is this rolling motion that creates a vortex.

Vortices are useful because they can be directed with reasonable precision and they also create a sealing effect. The semi-circular footplate and other indents on the main plane underwing are all designed to capture and direct vortices.

For example, air above the footplate is at a higher pressure than that below. Air will roll over the side of the footplate and is capture by the semi-circular channel sealing the rest of the main plane.

The front wing of 2014

There is no doubt that F1 teams have and will continue to invest a lot of aero resource in front wing development.

The FIA has consistently shown it is prepared to close down development avenues it perceives as not beneficial to the sport or the commercial automotive industry.

Don?t be surprised if come the next aero regulations overhaul in 2014 will see the ability to develop the front wing severely curtailed – we already know they’re going to be narrower.

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Lewis Hamilton, McLaren, Jerez, 2012

McLaren’s exhaust solution examined

Lewis Hamilton, McLaren, Jerez, 2012
The distinctive exhaust slot in the McLaren MP4-27

The FIA has introduced a raft of new rules aimed at curtailing the use of exhaust-blown diffusers.

Despite this, evidence from the first two tests suggests teams are using exhaust gases for aerodynamic benefit.

McLaren have come up with one of the more interesting solutions addressing the new restrictions on exhausts for 2012. John Beamer takes a look at what they’ve come up with for the MP4-27.

2012 exhaust rules

The new 2012 rules dictate the positioning of the final 10cm of exhaust piping. The rules specify that this section must be circular, thin-wall and 75mm in diameter.

Teams can have no entry or exit slots along the length of the exhaust. The exhaust exit must between 250-600mm above the reference plane, 500-1200mm from the real axle and 200-500mm from the car centre line.

In addition, the exhaust exit angle must be at positive 10-30 degrees from the reference plane (i.e., pointing slightly upwards) and plus/minus 10 degrees from the car centre line.

This is all aimed at limiting teams’ abilities to place the exhaust in a position that will increase the power of the diffuser. “The exhaust will still have an effect,” Ross Brawn admitted last week, “but it’s much, much reduced.”

The rules leave three apparent options for where designers may place the exhaust exit:

1. Towards either the rear or beam wing,
2. Over the suspension / brake ducts,
3. Away from the car altogether.

Based on early the first two tests it appears the top teams are blowing the exhaust gases over the suspension. However they are trying to seal the diffuser to replicate the benefits of the exhaust-blown diffuser.

It has been suggested that some teams are pushing the spirit of the rules but the so far the FIA hasn’t stepped in. The sport’s governing body may prefer to let the 2012 solutions pass and clean up the regulations for next year if needed.

McLaren MP4-27 exhausts

McLaren exhaust exit
McLaren exhaust exit

The first picture shows the new McLaren from above. In the blue circle it is easy to see the exhaust ‘bulge’ and exit channel. The fact it protrudes from the sidepod is the first clue that McLaren is trying to do something clever with the exhaust flow.

There has been a lot of speculation about exactly how the device works but it is likely to exploit the Coanda effect to seal the diffuser.

The Coanda effect is when fluid is guided by a nearby curved surface to modify its direction. As the surface curves away from the flow it creates lower pressure close to the surface. This pulls the fluid towards the surface.

McLaren exhaust exit
McLaren exhaust exit

The second picture is a side-on view of the exhaust. Again, the exhaust bulge is circled in blue.

From this angle you can see the exit slot is pointing towards the floor. This helps induce the Coanda effect and pulls the exhaust flow towards the floor as indicated by the blue arrow. Also the ‘bulge’ directs airflow coming around the sidepods away from the exhaust plume, protecting this flow to the diffuser.

McLaren exhaust exit
McLaren exhaust exit

The third picture shows the MP4-27 exhaust from behind with the blue circle highlighting the exhaust exit.

In this diagram the exhaust seems to contravene the regulations which states that it must be circular. The exit appears to have a protruding section and there are also two collars on top of the pipe which appear part of the exhaust. From the published photographs it is hard to see exactly what is going on and the team remains unsurprisingly coy.

There are several possible explanations for why this design may still be legal: these parts may not be attached to the exhaust – they may house sensors to monitor the temperature and flow of the gasses – or they may be an interim solution to allow McLaren to better understand the effect of blowing gasses over the diffuser.

Also in the third picture it is possible to see a number of temperature sensors on the topside of the diffuser ?ǣ these are circled in yellow. Given we’ve now seen this exhaust solution in two tests and McLaren’s performance looks pretty good it is very likely that the McLaren exhaust solution is working.

What the other teams are doing

Lewis Hamilton, McLaren, Jerez, 2012
Another view of the exhaust outlet on the McLaren MP4-27

Many other teams ?ǣ Ferrari, Mercedes and Sauber in particular ?ǣ all had similar but less aggressive solutions. Their exhausts were pointing in a similar directions to McLaren’s but without the bulge and bodywork.

Many teams also added vanes to their rear wing and floor to steer airflow to the diffuser. Don?t be surprised to see an innovative solution from Red Bull too ?ǣ engine suppliers Renault have indicated the world champions have some exhaust innovations coming.

Despite the FIA’s efforts 2012 will continue to see a lot of work on exhaust and diffuser development. But the early indications are teams have some way to go to recoup the downforce lost due to the new restrictions

Brawn added: “We’re still getting a bit of performance from the exhaust with the new car. Nothing like what was achieved with last year’s regulations and last year’s concept. But once you’ve discovered something you don’t un-invent it.

“All of the engineers, all of the designers in Formula 1 have been looking at how you can still retain some of the performance. But it’s far, far reduced to what we had last year and I think most people designing their new cars would be quite happy if they were able to achieve the overall performance that they achieved last year.

“We were testing in Jerez with the 2011 car and it looked to be the most consistent and fastest car there, in 2011 spec. All the new 2012 cars were a bit behind that.”

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Images ?? McLaren; Illustrations ?? John Beamer for F1 Fanatic

Sebastian Vettel, Red Bull, Interlagos, 2011

How the 2012 rules will influence F1 car design

Sebastian Vettel, Red Bull, Interlagos, 2011
Red Bull have been the class of the field in recent years

The 2012 season is the first since 2008 without significant changes in the technical regulations.

In 2009 we saw a reduction in aero appendages, refuelling was banned the following year, and the 2011 season was shaped by new Pirelli tyres, the introduction of DRS and return of KERS.

We’ve already had our first glimpse of a 2012 F1 car, but what will the other teams have in store for us this year?

Continuity and change in the 2012 rules

With the next major change coming in 2014 the rules for this season have undergone comparatively minor revisions. But there have been several tweaks which will make life interesting for F1 designers.

The changes include the banning of exhaust blown diffusers, restriction on engine mapping and a lowering of the maximum height of the front bulkhead. Further minor changes include a tighter definitions of how anti-stall systems must work and the extent to which wheel uprights can extend inboard.

One potentially significant change for the 2012 season which never materialised was a relaxing of the restrictions on weight distribution.

These were imposed last year due to the unknown characteristics of the new tyres. They acted as a safety net to ensure none of the teams got this fundamental aspect disastrously wrong and endured a season well off the pace.

One team with recent experience of this is Lotus, formerly, Renault. In 2007 the team failed to understand how the weight characteristics changed after switching from Michelins to Bridgestones, and endured a win-less season having won back-to-back championships in the two previous years.

The FIA originally intended to relax the weight distribution limits for the 2012 season. Its U-turn removes a wild card that could have shuffled performance among the top teams.

The exhaust-blown diffuser ban

Jaime Alguersuari, Toro Rosso, Suzuka, 2011
Exhaust-blown diffuser improvements spurred Toro Rosso late in 2011

The most significant rule change is the banning of exhaust blown diffusers. This is achieved by rules which dictate the position of the final 10cm of exhaust piping. The rules specify that this section must be circular, thin-wall and 75mm in diameter. This prevents odd-shaped exhausts with vanes to direct airflow. Teams can have no slots along the length of the exhaust so McLaren’s unraced ‘octopus’ exhaust wouldn?t be allowed.

An area for the exhausts’ exit is also defined by the rules. The FIA has also specified maximum and minimum exhaust angles. The limitations are not too restrictive but should move the exhaust exit some way from the floor area and prevent teams from blowing gasses close to the car’s bodywork.

F1 teams have spent an inordinate amount of money on perfecting exhaust blowing technologies over the last two years and the suspicion is that engineers will still be able to use that capability to blow exhaust gasses for some aerodynamic benefit. There are a number of possible options for where teams can blow exhaust gasses.

The obvious solution is to aim the exhaust at the rear or beam wing ?ǣ this is possible under the dimension restrictions in the regulations. Aiming the gasses at the underside of the wing at the car centre line will help keep airflow attached to the element and should result in a downforce increase. However, the interaction with DRS will be complicated and needs to be understood.

Valtteri Bottas, Williams, Abu Dhabi, 2011
Williams experimented with exhaust placement at the Abu Dhabi test

Another alternative could be to point the exhausts down outside the rear wing endplates and try to manage the wheel/diffuser interaction. In this set-up it may even be possible to create downforce around the suspension arms. But this is likely to prove a very difficult solution given the intricacy of the suspension and brake ducts in this area. And the distance between the area and the exhaust exits may make directing the gasses with sufficient accuracy impossible.

A further option is to blow the exhausts into the gap between the diffuser and beam wing. This shouldn’t have a huge effect on downforce but could aid airflow in the coke bottle zone. Lastly, the exhausts could be aimed out and away to prevent the gasses from interfering with the aerodynamics – but which designers would be happy to sacrifice the potential downforce gains?

It is likely that a lot of effort will be spent on modifying exhaust positioning throughout the season. At the young drivers? test in Abu Dhabi last year we saw both Williams and Mercedes run exhausts blowing the underside of the rear wing close the car centre line in preparation for the 2012 season.

Engine mapping restrictions

The ability to run different engine maps has been severely curtailed. Now the majority of driver inputs are ‘drive by wire’ ?ǣ in other words, they are processed by the engine control unit. Each driver input will have an ECU map by which input is mapped to output. There are two ways in which the throttle can be manipulated. The first is the pedal ?ǣ this controls how open or closed the throttle is. The second is how the throttle opening position delivers engine torque.

The FIA has attempted to link the pedal position, throttle opening and torque demand. In essence teams are allowed two ‘pedal shaping maps’ ?ǣ one for dry tyres and one for wet/intermediate tyres.

Also, the maximum pedal position must correspond to maximum torque demand of the engine and the regulations also specify how torque demand should increase with change in the pedal position. In addition there are limits on the gradient of the torque demand map and ignition offsets are prohibited under 80% of throttle or 15,000rpm.

Does this mean canny designers will still be able to take advantage of exhaust blown aerodynamics? It will be far harder but after two years of deep research designers have a much greater understanding of exhaust gas flows and so it is likely we’ll continue to see teams experiment with exhaust positioning to eke out every final advantage.

Nose height

Caterham CT01
Caterham's nose: The shape of things to come?

Since the 2009 regulations rewrite there has been a trend for higher noses. This is because a high nose allows maximum airflow under the car which can be shaped by the vanes and feeds the floor ?ǣ which is a major determinant of diffuser performance.

The problem with high noses is that the chance of the car flipping or spearing another car or drive in an accident is higher. The Technical Working Group has therefore been looking for ways to to restrict nose height.

Like all parts of an F1 car the definition of the nose height is complicated. The 2011 regulations allowed the top of the chassis and nose section to be a maximum of 625mm above the reference plane. The boundary height has been lowered to 550mm close to the front axle, which results in an inclined profile to the front wing.

The Caterham CT01, revealed on Wednesday, confirmed suspicions that this would produce an unattractive new breed of cars. Its ‘platypus’ nose hugs the 550mm boundary to allow maximum airflow under the car to feed the floor.

It is likely a typical example of what the front of an F1 car will look like this year. Just fore of the front axle the required 10cm drop is clearly visible. In addition Caterham have chosen to raise the suspension pick-up points in order to create maximum space under the nose.

This solution was common last year but in conjunction with the new nose regulations results in a car with dubious looks. Don’t be surprised if it becomes a common picture up and down the pit lane this year.

Reactive ride height

Kimi Raikkonen, Lotus, Valencia, 2012
Lotus's reactive ride system was banned

Recent weeks have seen much debate over the merits of a reactive ride height system Lotus ran during the young drivers’ test at Abu Dhabi. However on Friday the FIA announced the device was being banned for the coming season.

Ferrari also had plans to run a similar system from the start of the year and Mercedes were believed to be developing the concept as well.

The aim of the device was to stabilise ride height to increase downforce – much like the famed active suspension systems of the earlier nineties and, more recently, the J-damper and mass dampers introduced by McLaren and Renault respectively.

The FIA decided the system contravened article 10.2.3 of the technical regulations which states no adjustment may be made to the suspension system while the car is in motion, as well as some other rules.

F-duct 2.0

Michael Schumacher, Mercedes, Suzuka, 2011
Mercedes experimented with channelling airflow

The F-duct, introduced by McLaren in 2010 and widely copied that year, was banned for the 2011 season. But that hasn’t stopped designers looking into ways to exploit the thinking behind it for other purposes.

The original F-duct was a driver-activated fluid switch that allowed channelled air under the rear wing to create a turbulent flow. This prevented the air from attaching to the underside of the rear wing reducing downforce and also drag.

At the end of the 2011 season Mercedes tested a new front-wing F-duct based on a passive switch – i.e., one without influence from the driver. This is legal under the current regulations and has the potential to open up a new wave of passively-blown systems.

The Mercedes F-duct had an inlet at the front of the nose. Air is routed down the front wing pylons into a long but narrow slot across the breadth of the front wing. This is believed to incorporate a ‘passive switch’ which is dependent on air pressure, which in turn is dictated by how quickly the car is travelling.

There are competing theories about what Mercedes is trying to do with its front wing F-duct. There are two options ?ǣ either keep airflow attached to the wing and increase downforce or to stall the device as was the purpose of the original F-duct.

The placement of the exit slot ?ǣ near the leading edge of the wing – suggests that the most likely intention is to stall the wing rather than assist airflow. If the intent were to keep air attached the slot would probably be placed further back.

The most logical reason to do this is to manage front ride height – the team can reduce it without the risk of the car touching the ground at high speed.

Tyres

2012 Pirelli F1 tyres
Pirelli have altered their tyres for 2012

One the lessons of 2012 was the significant role that tyres play in F1. At the start of the season, while teams were getting used to the new rubber, we saw the most exciting racing and varied strategy – a view borne out by F1 Fanatics’ race ratings. Towards the end of the season teams had figured out how to set the cars up to optimise tyre performance and we saw less variation in performance.

During the Bridgestone era the focus was on tyre aerodynamic modelling to work out the car/tyre aerodynamic affects. The race tyres were so durable that they never really featured in race strategy.

Pirelli’s entrance into the sport has turned that approach on its head. Teams need to understand what combination of heat and cooling cycles will best cure the rubber for performance. In addition, understanding how to get the most out of a set of tyres is critical to race success.

In 2011 the Pirelli rubber behaved very differently to Bridgestone compounds. The trick with the Bridgestones was to get the tyre up to optimum temperature to create traction through chemical grip. This is less of a feature of the Pirelli tyres where the mechanical grip of the rubber seems to play a larger role.

Pirelli revealed details of changes to its 2012 tyres today. It includes a move towards softer compounds which they hope will recreate some of the early 2011 racing excitement. It will also be worthwhile seeing if the changes in construction alters the way the tyres behave.

As far as improving the quality of racing goes the fundamental problem remains: as teams increase their knowledge of the tyres and improve their tyre simulation techniques, so we are less likely to see the kind of surprises that can make for great races.

Other trends

Felipe Massa, Ferrari, Buddh International Circuit, 2011
Ferrari experimented with tha 2012-style front wing in India

The current generation of rules led teams focus their efforts getting the front wing as close to the ground as possible: whether through Lotus’s banned ride height system or the use of rake to lower the front of the car when it is moving.

The latter not only induces a ground effect but in turn lifts the rear of the car off the ground increasing the volume of air that passes through the diffuser. Provided sufficient air can be fed to the diffuser this, again, will increase downforce. Last year exhaust blown diffusers were a huge help in this endeavour by blowing gasses into the diffuser.

Either way, it isn’t hard to see how critical controlling ride height and rake is. Linked suspension is one way in which teams have tried to add ‘anti-dive’ to their cars. Basically the front and rear suspension systems are linked with a hydraulic line. During braking there is load transfer to the front suspension which can ‘draw’ on the hydraulic link to increase suspension stiffness and prevent excess dive.

This year is also likely to see further conflict around flexible front wings. Red Bull mastered this technology 18 months ago but its complexity has delayed up-take of the technology among its rivals.

Ferrari introduced their version in the last few races of 2011 but with limited success as it suffered from extreme ‘fluttering’. The trick is about composite design and lay-up ?ǣ no doubt all the big teams have been investing heavily to erode Red Bull’s lead.

Evolution or revolution?

Success in F1 today is mostly about incremental change rather than drastic innovation. That is why Red Bull have dominated for the past few years. They have a very strong base car with a deep understanding of its aerodynamic characteristics. Each year Red Bull fine tunes the chassis and suspension striving for ever-tighter component packaging to optimize downforce.

Contrast that approach to McLaren over the past two years. Their 2009 car was two seconds off the pace and the team started with a clean-sheet approach for 2010 around an oversized double diffuser. The diffuser was highly pitch sensitive meaning that the MP4/25 needed very stiff suspension to generate downforce.

The RB6 ?ǣ Red Bull?s challenger at the time ?ǣ was a much more rounded car built on an evolution of the RB5. Last year McLaren went clean-sheet again in designing the MP4-26 with L-shaped sidepods and radical ‘octopus’ exhausts. After struggling in testing the team ditched their exhausts on the eve of the new season and followed Red Bull’s lead.

It takes time and resources to build a complete aerodynamic picture of an F1 car. It isn?t difficult to see how much easier it is to obtain performance if a team is building from a strong concept rather than reinventing the wheel every season.

Given the strength of the RB7 and the stable regulations it is likely the Red Bull RB8 will be an evolution of its championship-winning predecessors. Ferrari, meanwhile, look set to reveal a substantially changed successor to the unsuccessful 150??? Italia.

The view in Woking will likely be that the MP4-26 was fundamentally inferior to the Red Bull, largely because the exhaust blown diffuser was retrofitted to the car and the L-shaped sidepods created aerodynamic compromises with cooling (requiring larger radiators) and airflow around the sidepods sealing the floor. Will they, like Ferrari, go radical in their pursuit of Red Bull?

Testing starts in a few weeks time and that will provide more data points as to who is where. However, it won?t be until Saturday at Melbourne that the true pecking order is revealed.

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Jenson Button, Lewis Hamilton, McLaren, Hungaroring, 2011

Mid-season technical review part 2

Jenson Button, Lewis Hamilton, McLaren, Hungaroring, 2011
McLaren have won the last two races

Guest writer John Beamer continues his look at the technical developments so far this year. Read the first part here.

McLaren work on their rear wing

McLaren has continued to bring upgrades to most races but many of the changes have been subtle ?ǣ the team hasn?t produce a big an upgrade package as Ferrari.

The biggest development in the pipeline is a revised rear wing similar with a shorter flap chord, similar to Ferrari?s new wing.

Red Bull’s ability to deploy its Drag Reduction System early in corner exits is worth several tenths of a second per lap in qualifying. It is this performance McLaren are looking for. However their new wing has yet to be raced because it gives worse overall performance on race day.

McLaren also modified its exhaust system and floor. The most obvious changes were the addition of vanes to the floor area below the rear wing end plate.

These have two effects: air exiting the exhaust is channelled over the diffuser generating downforce and it becomes harder for dirty air from the wheels to pollute the exhaust gasses.

Much of McLaren?s increased pace is thought to come from altering the car rake and getting the engine mappings right post-Valencia, where teams were banned from changing engine maps between qualifying and the race.

But it?s not as simple as ratcheting up the rake and expecting more downforce to follow. There will need to be subtle changes to the exhaust, floor, diffuser and bodywork.

Renault stick with forward exhausts

Nick Heidfeld, Renault, Hungaroring, 2011
Renault

Midfield teams continue to innovate as well ?ǣ with Renault perhaps being the most aggressive in recent races, particularly around the front wing.

At the Nurburgring they introduced a radical front wing design. A close look at the inner part of the cascade shows the team running a quasi-five element device.

There is a slot etched in the main plan (two elements) and the in-board middle flap has been split in two (another two elements), with the rear flap providing the fifth element.

As Craig Scarborough noted in a recent article, these are called Y250 vortices and are used to manage the componentry that lives 250mm from the car centre line: front wing pillars, under-chassis vanes, T-tray, bargeboards.

This is a critical area as it directly influences the air flow to the diffuser and around the sidepods.

Also at the German Grand Prix Renault tried more conventional rearward-facing exhausts, although the forward exhausts were raced and are likely to be kept for the rest of the season.

This is despite Nick Heidfeld suffering two separate exhaust fires in Spain (during practice) and Hungary.

Although the forward exhausts seem like a good way to increase airflow to the diffuser, performance has been less than was hoped. The extra space and cooling required by the new exhaust system makes the sidepods more bulky, which is detrimental to airflow around the sidepod undercut. Renault has struggled to develop the concept and has lost performance.

Mercedes mimic Red Bull

Nico Rosberg, Mercedes, Nurburgring, 2011
Mercedes are focussing on 2012

Mercedes has publicly stated it is no longer focusing on its 2011 challenger and will increasingly turn resources to next year.

However, two of the more obvious changes that Mercedes have made in recent races have been to revise its front wing and update the exhaust system.

The new exhaust brings Mercedes in line with Red Bull’s design. Its implementation was similar to that we saw last year with the exhaust existing below the sidepods and blowing over the floor. But it is likely to be less effective. The exhaust exits is moved rearwards, is flatter and has fences beyond its exit to control the airflow over the diffuser.

Oddly, Mercedes has elected not to use the out 5cm of the floor to create a sealing vortex like many other teams have.

At the Nurburgring the team came with an updated front wing. A couple of additional elements were added to an extended cascade in an attempt to better manage the vortices under the car similar to what Renault have done.

Mercedes is one of the few cars on the grid to sport a two-element front wing (ignoring the cascade) ?ǣ another unusual design choice from this team.

Rest of the season

The narrowing gap between the top three teams was reflected in the figures published on F1 Fanatic last week.

However a combination of unusually low temperatures for the German and Hungarian races, along with the exhaust-blown diffuser debacle at Silverstone, has clouded the true performance picture.

I suspect the role played by relatively low tyre temperatures in recent races has been more significant than has been widely understood. Once the Europe season is concluded and race temperatures increase I expect to see Red Bull remain the team to beat.

The other dynamic at this stage is the point at which teams switch focus to their 2012 cars. Given the lead Red Bull has and Sebastian Vettel have in the two championships their rivals may now be starting to pin their hopes on next year.

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Lewis Hamilton, Mark Webber, Fernando Alonso, Nurburgring, 2011

Mid-season technical review part 1

Lewis Hamilton, Mark Webber, Fernando Alonso, Nurburgring, 2011
It's now a three-way battle at the front

Guest writer John Beamer examines how Ferrari and McLaren have closed the gap to Red Bull.

Red Bull has a healthy, 103-point lead in the constructors championship. But does it still have the fastest car on the grid?

The RB7 has not won for three races, its lead in qualifying has been cut, and on race pace McLaren and Ferrari have often had faster cars.

It pays to be careful when making sweeping statements about performance, especially when track layout and tyre performance can have a dominating effect on race results.

But consider the Hungarian Grand Prix, where last year Red Bull were a second clear in qualifying, while this time Sebastian Vettel took pole position by less than two-tenths of a second partly because Lewis Hamilton made a couple of small errors on his final run.

The top teams’ recent technical developments gives some insight into how the battle for victory has changed.

Exhaust blown diffusers

Ferrari won their only race of the year so far at Silverstone – a weekend clouded by the row over exhaust-blown diffusers.

Prior to the race the FIA mandated that teams restrict off-throttle blowing to 10% of the full amount.

However, during Friday practice it emerged that Renault had permission to run up to 50% off-throttle based on a historical analysis of how it used its engines to aid valve cooling. This was in response to Mercedes being allowed to fire four of its cylinders off-throttle to relieve crank case pressure.

These changes remained in place for the race but were rescinded afterwards. That Ferrari won the race and McLaren struggled gave a lot of insight into the design of their 2011 cars.

The EBD restrictions were to limit the amount of hot-blowing, which many believed is what helped Red Bull secure such a large qualifying advantage, especially when it turned up the engines in Q3.

It turned out that Red Bull does not use hot-blowing. The team had tried hot-blowing in testing and free practice but it wrecked the rear tyres.

McLaren’s ‘octopus’ exhust

Lewis Hamilton, McLaren, Silverstone, 2011
McLaren struggled at Silverstone

McLaren , on the other hand, spent most of the off-season designing the MP4-26 around the infamous ‘octopus’ exhaust system, which did hot-blow the diffuser floor. The octopus exhaust was designed to release gasses across the full width of the diffuser but created too much aerodynamic sensitivity.

So they switched back to a conventional EBD layout before the Australian Grand Prix and picked up over a second a lap in time.

Although the diffuser was changed to accommodate the new exhaust system the aerodynamic principles relied on hot-blowing the exhaust. Fast-forward to Silverstone where hot-blowing was banned and McLaren suffered the most as the delicate balance of the car so apparent in the ‘octopus’ days returned.

Ferrari’s resurgence

Ferrari were off the pace early in the year partly because of wind tunnel calibration issues. That changed when they brought a radical upgrade package at Silverstone consisting of new rear bodywork, a revised exhaust layout, a new rear wing and floor.

That Ferrari got the harder compound working so well after struggling in previous races is a testament to the increased downforce generated.

Rear wing

Fernando Alonso, Ferrari, Valencia, 2011
Ferrari's earlier rear wing seen in Valencia

One significant performance differentiator in 2011 is rear wing design. This is intrinsically linked to the Drag Reduction System, which has a significant effect on laptime, especially in qualifying where DRS can be used feely.

To achieve this the wing needs to stall more aggressively in DRS operation. The trade-off is that this typically results in worse performance in total as airflow struggles to reattach when the DRS is deactivated ?ǣ Mercedes suffered from this issue in the first few races.

Ferrari extended the main plane and increased its camber. In turn the flap cord length is reduced. When DRS is activated the effect of the flap slot disappears and the air under the main plane stalls causing downforce to drop away more quickly.

Felipe Massa, Ferrari, Hungaroring, 2011
The rear wing Ferrari raced in Hungary

The wing was updated for Hungary practice. The flap chord was further shortened to give even greater drag reduction but so as to avoid losing too much downforce a Gurney was attached to the flap?s trailing edge. We may see this wing return at Spa, where drag reduction is especially important.

Rear bodywork

The other feature of the RB7 which Ferrari have tried to replicate is its distinctive coke-bottle rear bodywork, which allows cleaner airflow to the diffuser. Ferrari altered their rear bodywork, reworking the exhaust and radiator layout. The sidepods have also been extended rearward.

Normally designers try to create as much space as possible so superficially this seems an odd choice. There are two possible factors: first, the airflow wasn?t staying attached to the bodywork so by lengthen the sidepod this phenomena is being encouraged. Second, this new arrangement allows the exhaust construction to be simplified ?ǣ it is now sunk into the floor.

Sebastian Vettel, Red Bull, Barcelona, 2011
The back of the RB7 is very tightly packaged

Ferrari?s front wing has also been modified, with the most recent version appearing in Hungary. They have wavered between using a two- and three-element front wing. In one sense this allows them to choose the wing depending on the circuit but this approach is likely to be more expensive in development time and resources.

The outer section of the wing has reduced camber, which will cut downforce but feel more consistent and stable to drivers when steering. There have been changes to the cascades which now appear a lot more detailed than in the past ?ǣ the cascade is now dual element with a separator midway across its length.

Also, the forward-facing camera is mounted directly behind the central section where it looks like a second section. The two cameras appear to join so it looks like a single section ?ǣ presumably the FIA is happy with this construction.

Red Bull’s rake

Sebastian Vettel, Red Bull, Silverstone, 2011
The thin wedge of light under the RB7 shows the angle of rake

A noticeable trend over the last few months has been the degree of rake the Red Bull cars run. For the uninitiated, rake is the nose to tail angle that the car runs. A car with a lot of rake has its nose closer to the ground while its tail is higher.

Why is this an advantage? The theory is that by running a lot of rake the front wing is closer to the ground where it is more effective. In addition the diffuser is at a steeper angle. Both phenomena, in theory, create more downforce. Let?s look at both of these in more detail.

Rake and the diffuser

Downforce in the diffuser is a function of height above the ground and slope. The steeper the diffuser the greater the downforce. A higher diffuser creates less downforce and also raises the centre of gravity. Both of these are only true up to a point – push them too far and all performance is lost. Adding rake to a car is trading off these phenomena.

One of the reasons why increasing diffuser height cuts downforce is because the diffuser becomes more prone to stalling. Red Bull realised that it could harness the power of the exhaust blown diffusers to mitigate this.

The exhaust gasses add energy to airflow in the outer part of the diffuser and prevent turbulent air from rear tyres entering the diffuser (acting as a seal). This reduces the effect of increasing the height of the diffuser.

Rake and the front wing

The 2009 technical regulations allowed the front wing to be run much closer to the ground than in previous seasons. This meant that the ground effect came back into play.

Ground effect is the same phenomena associated with changing the diffuser height. The lower the wing is to the ground the more downforce is generated ?ǣ this is commonly known as the Venturi effect. Adding rake in conjunction with exhaust blown diffusers results in a considerable downforce benefit.

Teams follow Red Bull’s lead

Felipe Massa, Ferrari, Hungaroring, 2011
Visible rake on Massa's car in Hungary

Red Bull has run a lot of rake for the best part of a year, and in recent races that McLaren and Ferrari have begun to follow suit. Is this a factor in the more competitive running order? Almost certainly.

This was particularly so in Hungary where Vettel abandoned a new front wing and floor design after Friday practice. The team had to break the FIA-imposed curfew to return the car to its Nurburgring configuration.

The main problem was the revised front wing and under-chassis turning vanes. The front wing pillar was wider and consequently the turning vane was deleted. In addition the trailing edge of the front wing flap sported a gurney and the cascade profiles were changed.

The addition of the gurney was interesting as this is usually a quick way to increase grip at low speeds. Although these changes seem minor, a small change at the front of a car can have a significant effect further back.

The updated diffuser, which was in all probability updated to work with the new front wing, sported a few subtle changes (externally at least). The central section below the rear crash structure contained a new fence structure and the vanes in the primary diffuser channel were lengthened.

It?s unclear what Red Bull is trying to achieve with these updates but presumably by adding/extending these vanes the intent was to better control and direct airflow exiting the diffuser.

This is a very sensitive part of the car as the pressure gradient aft of the diffuser determines how much downforce it generates. Too steep a gradient and the diffuser is more prone to stalling.

Don’t miss part two of this article tomorrow which will look at McLaren’s progress this year and significant changes in the midfield teams.

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Felipe Massa, Ferrari, Montreal, 2011

Technical review: 2011 Canadian Grand Prix

Guest writer John Beamer reviews the technical changes on the cars at the Canadian Grand Prix.

Rear wings

Before the new 2009 regulations we tech spotters used to see much more variation in aerodynamics at the different races ?ǣ especially at high-downforce Monaco, and low-downforce Montreal and Monza.

But these race-to-race changes have more or less disappeared.

Take Monaco, for example. In the past teams would turn up with an impressive array of aerodynamic appendages to try to maximise downforce around the principality. Here top speeds are not a factor so teams are willing to add downforce at the cost of drag, a trade-off that wouldn?t be made at, say, Barcelona.

However, this year at Monaco teams didn?t bring any new high downforce components – all they did was ratchet up the wing angles.

So what about Canada? The track favours a low downforce set-up, similar to Monza, but not as extreme. The Gilles Villeneueve circuit consists of a series of lengthy straights, a few chicanes and an slow hairpin with no high-speed corners to speak of.

Naturally all teams came with low-profile rear wings but most were simply existing wings with modified angle. Williams and Renault were among the few to use new, low-downforce concepts, both of which featured twisted spans.

Renault

Nick Heidfeld, Renault, Montreal, 2011
Nick Heidfeld, Renault, Montreal, 2011

Renault had an M-shaped wing which eagle-eyed readers will recall was an approach used on the car for the Canadian Grand Prix last year. The idea is to try to optimise load distribution across the length on the wing.

The curvature either side of the centreline aligns better with the incident airflow so presents a reduced angle wing. The theory is that this increases the aerodynamic efficiency (defined as the downforce-to-drag ratio) of the wing by better reflecting the shape of the incoming airflow.

Williams

Pastor Maldonado, Williams, Montreal, 2011
Pastor Maldonado, Williams, Montreal, 2011

The Williams concept was a little different. It is shovel-shaped to try to increase downforce over the middle part of the wing where the airflow is cleaner.

By making the mid-wing do the work the pressure gradient is reduced at the endplates, which produces smaller vortices and less drag.

Designers are investing substantial resources in optimizing the DRS system and this is also evident in the Williams design.

The flap has a short chord and its job is to keep the airflow attached to the underside of the main plane. The flap extends the low pressure area behind the rear wing which in turn increases downforce of the device. When the DRS is activated this low pressure area drops away and the lee-side of the main plane stalls, causing a large drop in drag (and downforce).

Neither Renault nor Williams ran their new front wings in the race because of the threat of rain.

There were also fears that the super-soft tyres would last only a few laps. Under this scenario more rear downforce would help preserve the tyres.

This also explains why McLaren opted to run its cars with more rear downforce and was one of the reasons why Jenson Button was so much faster than Sebastian Vettel on the drying race track at the end of the race.

Front wings

One reason why we don?t see vastly different car configurations on a low downforce circuit like Montreal is because of the extreme aerodynamic sensitivity of the cars. Following the 2009 regulations changes, teams achieve optimal downforce by treating the car as a system.

Ostensibly this means tailoring the intricate front wing design to optimise airflow to the sidepods and floor. However, given the sensitivity of the aerodynamics, teams don?t have a lot of latitude to radically change the front wing because all their aero optimisation work will be undone ?ǣ this is 18 months-worth of intensive CFD and wind tunnel analysis.

As a result teams rarely produce radical new front wing designs ?ǣ the last such example was probably McLaren which introduced the split cascade to manage airflow around the tyres in the middle of 2010.

Interestingly for Canada Williams introduced an endplate-less front wing. The endplates were merged into the cascades and a horizontal vane is attached to the integrated endplate to manage air to the tyres.

In addition a fence was placed underneath the outer part of the cascade in order to control the vortices below the front wing. This will aim a vortex outside the tyre to try to reduce wheel drag.

Ferrari?s suspension

Felipe Massa, Ferrari, Montreal, 2011
Felipe Massa, Ferrari, Montreal, 2011

One of the surprises when the 2011 cars were launched was Ferrari’s decision to stick with pushrod rear suspension at a time when many other teams were following Red Bull’s lead in switching to a pullroad configuration.

The Scuderia was very aggressive with its placement of the suspension pick-up points to try to create as narrow a back-end as possible. The intention is to enable as much air as possible to channel to the coke-bottle zone and over the diffuser. One consequence of this set-up is that Ferrari is quite harsh on its rear tyres, particularly the harder compound.

In recent races the team has subtly altered the suspension pick-ups to try to better manage the rear tyres. By fine tuning suspension pick-ups it is possible to control the weight transfer under breaking, accelerating and cornering. The team is no doubt attempting to get a more consistent weight distribution to the rear tyres under dynamic conditions.

Another suspension innovation that Ferrari has adopted is a dual-rate anti-roll bar. As its name implies the anti-roll bar resists roll ?ǣ in a road car you can feel the car rolling when cornering. The stiffer the bar the greater the resistance to roll. A stiff bar will keep the car at a consistent attitude, which is beneficial for aerodynamics. A softer bar will give more mechanical grip when cornering.

Dual-rate anti-roll bars give the best of both worlds. Typically a stiff bar is attached to the suspension with a soft-sprung coil. The coil gives compliance when cornering but quickly becomes fully compressed allowing the stiffer anti-roll bar to resist rolling motion.

Changing regulations

The debate over the future technical direction of F1 continues. After the Canadian Grand Prix it was confirmed that from Silverstone teams would be limited in their application of hot-blowing diffusers.

When off the pedal the throttle is only allowed to be up to 10% open – many teams maintain full throttle opening, especially in qualifying. To restrict this the FIA has also mandated that, from this weekend, engine maps must not be changed after qualifying (unless a driver starts from the pitlane). This means that teams will have to run less aggressive maps in qualifying.

The impact is likely to be significant, especially for Renault and Red Bull, the two teams that first developed the technology.

The most intriguing dynamic is whether Red Bull’s qualifying advantage is reduced – given the RB7 has almost a second on its rivals in the hands of Vettel I suspect the Milton Keynes-based outfit won’t be too concerned. However, we will need to wait a couple of weeks before we know exactly what the regulation change has done to the running order.

The bigger change affects the 2012 regulations where exhaust-blown diffusers have been banned.

An early proposal was for the exhausts to extend a minimum of 330mm behind the rear wheel centre line, which is at the trailing edge of the diffuser. This would have prevented the use of blown diffusers but would have incurred significant costs as teams produced longer exhaust pipes.

There was also a strong likelihood that teams could still take advantage of the blown effect to reduce the pressure gradient aft of the diffuser or underneath the beam wing, both of which would yield a performance advantage.

A compromise has since been reached whereby the periscope exhausts of years gone by will be mandated. It is unclear how the regulations will be written to ensure this happens but it will mean that there is very low chance of the exhaust gasses being put to aerodynamic use.

This is a guest article by John Beamer. If you want to write a guest article for F1 Fanatic you can find all the information you need here.

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Mark Webber, Red Bull, Montreal, 2011

F1 technology in 2011 part 2: Diffusers and more

In the second part of his look at technical developments in 2011, John Beamer examines the hot topic of exhaust-blown diffusers.

Also, a look at the ongoing dispute over the new engine rules for 2013.

Exhaust Blown Diffusers

Renault R31 exhaust, Valencia, 2011
Renault R31 exhaust, Valencia, 2011

After much commotion at the start of the season with Renault’s sidepod-exiting exhausts and McLaren’s infamous aborted ‘octopus’ the majority of the front-runners have now imitated Red Bull?s design.

The regulations allow slots in the outermost 50mm of the floor. Red Bull tunnel the exhaust under the floor and exits them in this ‘free’ zone, feeding the hot exhaust gasses into the diffuser.

There are two alternative designs. One is to use the starter motor hole for the same effect but the slot is small and the performance gains minimal.

The second is to simply blow the exhaust over the top of the floor, which doesn?t feed the diffuser directly but does create a region of low pressure aft of the diffuser structure reducing the pressure gradient under the floor. Mercedes has stuck with this solution.

This configuration has caused Mercedes much trouble with overheating rear tyres. In Spain the floor of the Mercedes sprouted a turning vane beside the rear tyre to channel air away from the rubber.

Hot-blown diffusers

One trend to go hand in hand with exhaust blown diffusers has been the application of special engine maps to ensure a consistent flow of exhaust gasses even when the driver is off throttle. This has been dubbed ‘hot-blowing’, but it is set to be heavily restricted after the next race in Valencia.

By retarding the ignition and igniting fuel in the exhaust when the throttle is closed, hot gasses continue to feed the diffuser, generating more downforce.

This technique has a dramatic effect on fuel consumption. Renault estimated that its engines are consuming around 10% more fuel in a race then they were last year because of the retarded ignition approach.

Teams runs two maps: one for qualifying where more fuel is burned to drive faster, more consistent flow; and one for race day which burns less fuel.

A week before the Spanish Grand Prix the FIA made the surprise announcement that off-throttle diffuser feeding was to be restricted.

The precise wording of the revised regulation is still pending but it is likely to mandate engine throttles closing to 10% of their maximum when the driver is off the gas. That is a significant change and will vastly reduce the efficacy of engine mapping.

All the front teams are effected ?ǣ especially Red Bull and Renault ?ǣ and a protest delayed the introduction of the ban until Silverstone. Renault in particular could suffer as the front exhaust exists are likely to suffer a larger performance drop-off under the proposed regulation changes.

Flexible bodywork

Mark Webber, Red Bull, Montreal, 2011
Mark Webber, Red Bull, Montreal, 2011

Another controversy from 2010 that has refused to die down is the application of flexible body work, particularly for the front wing.

Recall that Red Bull?s car seemed to magically lower its nose at high speed creating extra downforce. Despite the FIA?s attempts to tighten the regulations the RB7 sports the same advantages.

After the Malaysian Grand Prix, when it was clear that Red Bull still had an advantage, utterances from Aldo Costa (Ferrari’s technical director at the time) and Ross Brawn suggested that they believed the more stringent regulations would put an end to flexible bodywork.

They didn?t. Rather, it appears that under the static load test the RB7?s front wing flexes less than its rivals.

However the test is still flawed. In full flight the RB7?s wing flexes a little down but also appears to move backwards a little. This degree of fine tuning will take a lot of skill (not to mention expense in terms of computer software and resources).

It’s fairly straightforward to achieve this kind of bending. By altering the composition of the carbon fibre lay-up process the final, cured product will exhibit different tensile characteristics. There are many parameters at play include lay-up orientation, autoclave temperature/curing time, fibre thickness, resin constitution, and so on.

But the difficult part is controlling these variable to make a wing that behaves exactly as desired under load.

This requires deep understanding of structural mechanics as well as flow analysis ?ǣ a combination of Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) techniques.

Despite the immense computing power F1 teams throw at CFD their simulations can only provide an estimate of actual flow ?ǣ throw in the need to solve FEA equations and the problem compounds. It is thought that through a venture with MSC Software that Red Bull has managed to get around some of these problems and has a very good read on the FEA-CFD interlinks.

2013 regulations

The 2013 regulations, in particular the rules, have received a lot of attention.

Engines

At the last World Motor Sport Council meeting the FIA said the controversial new engines rules could be postponed pending a vote to be taken by the end of the month.

The FIA announced in December a switch to 1.6 litre, 4 cylinder engines would take place in 2013. These would include a more powerful Kintic Energy Recovery System and turbo-charging to produce roughly the same power output as the current V8 engines do.

The hopes this might entice more car manufacturers to enter the sport appear to have been in vain so far. Volkswagen, one car manufacturer which was being targeted, instead announced it would compete in the World Rally Championship.

The only engine builder not currently active in F1 to announce plans so far is PURE, a new manufacturer led by former BAR team principal Craig Pollock.

Along with a feeling that the new rules have not had the desired affect of attracting new manufacturers, there are concerns about the cost of building engines for a new formula.

But in seems inevitable the sport will ultimately need to embrace a more modern solution that follows the car industry trend for smaller, less thirsty engines.

Aerodynamics

There will also be changes to the aerodynamic rules. Initially a proposal was put forward to simplify the front wing and allow more design freedom underneath the car as this was thought likely to improve overtaking.

However, as we?ve seen this year, altering mechanical grip (via the new Pirelli tyres) is a more effective way to encourage overtaking. Some teams were worried that removing the shackles from floor development would just create a new aero arms race just as costly as the current one.

History supports that hypothesis and as a result those plans have been scaled back. The 2013 aero regulations will be based on the 2011 rules but with tweaks to reduce the design intricacy of the front wing and to further restrict bargeboard and sidepod wing development, which the original 2009 rules did not completely eliminate.

This is a guest article by John Beamer. If you want to write a guest article for F1 Fanatic you can find all the information you need here.

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Sebastian Vettel, Red Bull, Montreal, 2011

F1 technology in 2011 part 1: Tyres and DRS

In the first of a two-part series looking at trends in technology in 2011, John Beamer talks tyres and the controversial Drag Reduction System.

Tyres

Fernando Alonso, Renault, Silverstone, 2005
Fernando Alonso, Renault, Silverstone, 2005

As pre-season testing indicated, the characteristics of the Pirelli rubber are very different to the old Bridgestones. It?s worth going through a bit of history to understand how we got here.

Ten years ago pit stop strategy was an essential element of Grand Prix racing. The tyres would wear out quickly and teams had to work out whether the speed advantage of a series of short sprints outweighed the cost of spending more time trundling down the pitlane. The problem was that Ferrari and Michael Schumacher were imperious and the spectacle was dull.

To try to spice things up in 2005 the FIA banned tyre changes. The thesis was to bring tyre management into play and make the sport more exciting.

The tyre companies (Bridgestone and Michelin) at the time poured research in to developing more durable compounds that wouldn?t degrade so much over a 300km race.

The racing was better but this was because the Michelin-shod teams had better rubber and were able to close the gap to Ferrari who stuck with Bridgestone.

Then came the ill-fated 2005 US Grand Prix where the high lateral loads caused by the banked Indy speedway dangerously weakened the sidewalls of the Michelins.

We all know what happened next ?ǣ the Michelin teams weren?t allowed to race turning the Grand Prix into a farce. That saw the sport scarp the ‘no tyre change’ rule and move to a single supplier for tyres (Bridgestone) for 2007.

The 2007 control tyre was based on the compound developed in 2005 and the tyres were very durable ?ǣ degrading a maximum of a 0.05s per lap. Fuel stops still gave a strategic angle to race day.

It wasn?t until 2010 and the refuelling ban that the F1-watching public started to cotton on to how important tyres were in deciding the outcome of a Grand Prix.

Sebastian Vettel demonstrated how durable the super-softs were last year in Monza when he ran them for practically the entire race distance.

Sebastien Buemi, Fernando Alonso, Lewis Hamilton, Montreal, 2010
Sebastien Buemi, Fernando Alonso, Lewis Hamilton, Montreal, 2010

A few races earlier, the combination of compound choice, rain and asphalt characteristics turned the Canadian Grand Prix into an overtaking bonanza as the tyres lasted a handful of laps.

These events dovetailed with Bridgestone?s decision to exit the spot and when Pirelli was selected as F1?s sole tyre supplier it was give the mandate to make rubber that would degrade faster.

In the Bridgestone days the biggest problems the teams had was graining. This is when the first layer of rubber is torn by the asphalt temporarily resulting in reduced grip. Once the graining phase was over the tyres would work as normal.

Simply put, the Pirellis don?t grain. The tyres just degrade ?ǣ the rubber is more consistent throughout the tyre and it wears away (hence the marbles which appear off the racing line).

Driving style has a limited effect on degradation. Witness Lewis Hamilton having to claw back places in Turkey following a poor start ?ǣ his tyres were done a couple of laps before the others.

Drivers have to work out when to push and when to hold back but the point is that two drivers going the same speed will have a very similar degradation pattern whereas with the Bridgestones there was more scope for managing the tyres.

The other point of note is the extent to which the Pirellis amplify the difference between team mates, particularly in qualifying.

Vettel, Hamilton, Alonso and Rosberg have consistently outpaced Webber, Button, Massa and Schumacher respectively ?ǣ and typically by a greater margin than last year:

DRS and rear wings

Sebastian Vettel, Red Bull, Montreal, 2011
Sebastian Vettel, Red Bull, Montreal, 2011

The Drag Reduction System is probably the most radical rule change to F1 since shaped under floors were outlawed.

As everyone who reads this site knows the flap may open by a distance of 50mm reducing its angle of attack. Drag squares with speed and the open flap allows cars to find roughly 10-15 kph on the straight.

As we saw in Turkey the effect DRS has in the race can be substantial. However, perhaps the bigger and much less discussed consequence is that Red Bull?s qualifying dominance is largely down to its ability to use DRS where others can?t.

At the recent Spanish Grand Prix, coming out of the last corner the RB7 had its wing open entering the last corner where as the McLaren, its closest challenger, waited until the car was past the corner apex. It confirms how much raw downforce the Red Bull has.

On an average track in qualifying trim the RB7 has a second a lap advantage over the MP4-26. That?s huge. On Sunday when DRS use is restricted the gap contracts to a less jaw-dropped 0.2s (and McLaren believe they are quicker over a race distance), which goes to show how unrestricted use of the DRS exaggerates the performance gap.

Michael Schumacher, Mercedes, Montreal, 2011
Michael Schumacher, Mercedes, Montreal, 2011

In addition the design of the DRS system and rear wing can also effect performance. The Mercedes has the most aggressive DRS design.

The chord length of its rear wing flap is short and in the early races when the DRS deactivated it took too long for airflow to reattach to the underside of the flap. This meant that downforce couldn?t be recovered quickly enough and was one reason why Schumacher and Rosberg struggled during qualifying in the early races.

Ferrari’s banned rear wing

Felipe Massa, Ferrari, Barcelona, 2011
Felipe Massa, Ferrari, Barcelona, 2011

There wasn?t a lot of innovation in rear wing design until Ferrari appeared in Spain with a raised lip on the trailing edge of the rear wing (pictured) that resembled a gurney flap – and caused the rear wing to exceed a maximum height threshold.

Closer inspection revealed that the trailing edge is part of the extended wing separators as specified by article 3.10.3 of the technical regulations.

The article mandates two central supports between 2-5mm thick and a maximum distance of 30mm from the wing surface that fully enclose both the main plane and flap of the wing. Ferrari joined the two separators together and then split them at the trailing edge of the flap so they then shadow the rest of flap along its length, 30mm from the trailing edge.

The benefits were obvious with the device acting a gurney flap, which is an efficient way to add downforce to the car. However, before free practice 3 the FIA deemed that Ferrari?s innovation contravened the regulations and it was banned.

At the start of the 2011 campaign there were fears that the writing of the DRS regulations would introduce new loopholes that canny teams would exploit to produce the 2011 equivalent of the f-duct. So far it hasn?t happened ?ǣ at least not to the naked eye.

The only parameters that designers can tweak are chord length and profile thickness. A shorter flap (i.e., small chord length) will shed drag more quickly when open but will produce less downforce when closed.

The second part of this article tomorrow will look at exhaust-blown diffusers, flexible bodywork, and the planned changes for 2013.

This is a guest article by John Beamer. If you want to write a guest article for F1 Fanatic you can find all the information you need here.

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Images ?? Renault/LAT, Bridgestone/Ercole Colombo, Red Bull/Getty Images, Daimler