The coil pack is handed over and the challenge starts...

The first job was to fit the coil pack. The four-pronged carbonfibre cased unit is a press fit atop each spark plug, then the we needed to connect CAN electronics interface near the front of the airbox.

Next the heatshield goes on... (eventual challenge winner watching intently behind)

A small reflective coated carbonfibre heatshield goes over the coil pack, attached with three small bolts, one of which is smaller and requires a different torque setting.

Access to the 24 exhaust studs under the engine was surprisingly good

Then onto the exhaust system, weighing about 3kg each exhaust is hand made from thin sections of inconnel welded together. Although the 4-into-1 exhaust is one assembly, there is some play in the primary pipes joints with the collector, so fitting the four exhaust pipes to the studs on the engine requires a little fiddling. Each exhaust pipe bolts to the exhaust port with three nuts, two above and to the side of the exhaust pipe, and one centrally below.

A blur of hand movement gets each nut threaded on...

Each of these 24 nuts being tightened to the same torque setting. With the engine up on the stand and being able to kneel below the engine, getting access to each fastener was surprisingly easy, none of the exhaust pipes being particularly obstructive. I’m sure doing the same job with the engine in the car and the floor fitted is a very different story.

A quick check that each nut is torqued correctly and the job's done.

I completed the challenge in 4m 30s and I was satisfied I’d done a good job. However ex Racecar Engineering magazine editor, Charles Armstrong Wilson completed the challenge in an impressive 3m 30s! Even though one (un-named) journalist took as long a 7m 57s, as group us journalists were confident we’d done a good job. But the teams Drivers had soundly beaten us all. Nico Rosberg did the challenge in 3m 15s, while Michael Schumacher did it thee minutes dead!

The job of the F1 engine builder and mechanic is a difficult and skilled one, the skills of the F1 driver are ever impressive and I’ll stick to drawing racecars and not working on them!

One of Max Mosley’s lasting legacies in F1 was the introduction of his vision of a green initiative in F1. As a result KERS (Kinetic Energy Recovery System) was introduced 2009, as part of a greater package of rule changes to change the face of F1.
KERS is a system which harvests energy under braking and stores it to provide the driver with an extra power boost each lap. A simple technical summary of KERS is here (http://scarbsf1.wordpress.com/2010/10/20/kers-anatomy/ ).
During the 2009 season McLaren were applauded for running Mercedes KERS at every race and it was widely reported as the best KERS in use that year. Along with a few other journalists, I was invited along to Mercedes AMG Powertrains in Brixworth, UK to hear about KERS development since 2009. With Managing Director Thomas Fuhr and Engineering Director Andy Cowell giving a presentation on the range of work Mercedes AMG does with its F1 teams.

Mercedes AMG Powertrains reside on the site that was previously Mercedes Benz High Performance Engines (MBHPE). Now renamed to reflect the wider application of the groups knowledge, both to uses outside F1 and to areas other than engines. Powertrain is a catch all term covering; engine, transmission, electronics and of course KERS Hybrid systems.
The company have built a purpose designed Technology Centre on the site, which historically was the Ilmor engine plant and positioned just a few miles from Cosworth in Northampton. Clearly this area has a rich seam of Engine knowledge.
Formed around three buildings the entire F1 engine and KERS development is carried out on site, only specialist functions such as the casting of the crankcases is carried out off site. Additionally other Mercedes AMG work is carried out here, such as the AMG E-cell car.

KERS 2009
Mercedes AMG (MBHPE as it was known then) developed their first KERS for 2009 in house. At the time McLaren were the primary customer for the system, although Force India and at the last minute Brawn GP were also customer teams that year.  Force India had a chassis prepared to run KERS, but chose not to during the season.  Brawn had a chassis designed before their switch to Mercedes engines, so their car was not designed to accept the Mercedes KERS.

Mercedes AMG: 2009 Battery pack and water cooling radiator

In designing the system, Mercedes AMG had a specific requirement from McLaren. As the effectiveness of KERS was unknown, McLaren didn’t want to compromise the car if KERS was removed. So the system was packaged to fit into a largely conventional car. Whereas other KERS suppliers went for a battery position under the fuel tank, McLaren and Mercedes AMG placed theirs in the right hand sidepod. Low down and far forward, on the floor between the radiator and the side impact structures. The battery pack contains not only the array of individual cells, but also the pump and pipe work for its water cooling circuit. As well as the electronic interfaces for its control and monitoring. The assembly is around 7cm high, 12cm wide and 40cm long. The KBP is probably the single heaviest KERS component. In 2009 this sidepod package was acceptable as the teams were still on Bridgestone tyres and seeking an extremely forward weight distribution. Thus the 5cm higher mounting in the sidepod was offset by its forward placement.

2009 KERS and the batteries sidepod location relative to the engine

Conversely the smaller Power Control Unit (PCU) was placed in a similar location in the other sidepod, ironically the PCU is around the size and shape of road car battery. This left the monocoque uncompromised, aside from the smaller cut out for the MGU in the rear bulkhead.

The 2009 Zytek developed MGU

Then the Motor Generator Unit (MGU) is mounted to the front of the engine.  This device generates and creates the power for the KERS. Its driven from a small set of gears mounted to the front of the crankshaft.  the unit remains with the engien when the car is dismantled and is oil cooled along with the engine.

All of the components are linked both to the SECUs CAN bus and to each other by High Current Cable. The latter taking the DC current between the Batteries and MGU. With this packaging Mercedes AMG quotes the total system weight as 27kg.
Designed and developed by Mercedes AMG, but other partners were involved; the unique battery cells were supplied via A123 and the MGU was partnered with Zytek. Although the power control electronics were solely a Mercedes AMG in house development.
Through the 2009 season both McLaren drivers had a safe and reliable KERS at each race. The system was safe even after crashes and was fault free despite rain soaked races. Safety was designed in from the outset, all electrics were double insulated. Teams can also measure damage to the unit via accelerometers and insulation sensors, so any impact or incidental damage can be monitored and the car retired if the need arises. Additionally each cell in the battery has its temperature monitored. KERS batteries are sensitive to high and low temperatures, each cell needing to operate in a specific thermal window. Too low and the unit is inefficient and too hot and there’s the danger of explosion.
Perhaps the only criticism was the sidepod battery mounting, despite several incidents, this never put any one in danger, so this never proved to be an unsafe installation.

KERS 2011

2011_Mercedes_AMG_engine

For a variety of non technical reasons KERS was agreed not to be raced from 2010 until the planned 2013 rules. However this plan changed, but not before Mercedes AMG had made new strategic plans around KERS.
Mercedes AMG set out a longer term strategy to work on research for KERS in preparation for 2013, as well as working with AMG to develop the road car based E-cell technology.
(Link Mercedes AMG E-Cell chassis  )
This changed when the plans for the 2013 engine were pushed back to 2014 and KERS was agreed to be reintroduced for 2011. Thus the 2013 development plans had to rebased and deliver a refined version of the 2009 KERS for 2011. Moreover there were now three teams to be supplied with KERS. There was no Christmas for Mercedes AMG staff 2010!
As a result of the research work carried out after 2009, Mercedes AMG now solely design, develop and produce the entire KERS package, aside from the Battery cells. So now the MGU is a wholly Mercedes AMG part.

The MGU fits to the front of the engine and driven from a small set of gears

With KERS effectiveness proven in 2009, it was possible to have the cars designed around it, rather than it be an optional fitment. So the packaging was revised and the entire system integrated into just two units. The MGU remains attached to the front of the engine, still driven off a spur gear on the nose of the crankshaft. While the KBP and PCU are now integrated into a much smaller single package and fitted under the fuel tank. The unit bolts up inside a moulded recess under the monocoque, the unit being attached using four vibration mounts, and then a closing panel and the cars floor\plank are fitted under it.

The 2009 battery pack (yellow) is now integrated with the power electronics (not shown) in a single unit under the fuel tank (red).

It’s this integration of the batteries and power electronics that has has really slimmed the 2011 system down. Mercedes AMG now quote 24kg the entire KERS, much of the 3kg weight loss being down to the reduction in the heavy power cabling between these units.
Not only is the packaging better, but the systems life and efficiency is too. Round trip efficiency stands at a stated 80%, which is the amount of power reapplied to the engine via the MGU after it has been harvested and stored. Improvements in efficiency being in both the charge and discharge phases.
Battery pack life was extended to as much as 10,000km, several times the 2009 predictions that batteries would need replacing every two races (2,400km). Over this period, the cells do not tend to degrade, as the team manage the unit’s condition (‘State of Charge’ & temperature) throughout the GP weekend to maintain their operational efficiency.
The 80hp boost KERS provides, stresses the engine. This was well known back in 2009, but for 2011 along with DRS the car can be several hundred revs higher than the usual EOS (end of straight) revs. Mercedes AMG quoted 15-25% more stress for a KERS and DRS aided lap, this needing to be taken into account when the team monitor the engines duty cycle, thus deciding when to replace it. Mercedes conducted additional dyno development of the engine being kept on the rev limiter to fully understand and counter this problem. This work paid benefits; Hamilton ran many laps at Monza bouncing off the rev limiter along the main straight, while chasing Vettel.

KERS in use
Although the max 60KW (~80hp) output can be reduced from the steering wheel, its normal for the driver to use the full 80hp boost each time they engage the KERS boost. With a reliable KERS, the driver will use the full 6s boost on every lap. Media reports suggest Red Bulls iteration of the Renault KERS does not use this full 60kw. Instead something like 44kw, providing less of a boost, but allowing smaller batteries to be used. The loss in boost being offset by the overall benefit in car packaging.
The driver engages a KERS boost either via a paddle or button on the steering wheel, or by the throttle pedal. The latter idea being a 2009 BMW Sauber development, where the driver pushes the pedal beyond its usual maximum travel to engage KERS. Nick Heidfeld brought this idea to Renault in 2011 and the over-extended pedal idea has also been used for DRS too.
Once the driver is no longer traction limited out of a turn, they can engage KERS. Usually a few small 1-2s boosts out of critical turns provides the ideal lap time. It’s the driver who has to control the duration of the boost, by whichever control. As with gear shift the drivers can be uncannily accurate in their apportioning of the boost around the lap. It’s suggested that the 2009 Ferrari system apportioned the duration of the KERS boost via a GPS map, the driver simply presses the button and the electronics gives them the predetermined amount of boost. This solution came as surprise to Andy Cowell, so one wonders if this is legal or perhaps if the report is true.
From on board shots, we’ve seen the steering wheel has an array of LEDs or numerical displays to show the driver the boost remaining for that lap. The SECU will have control code written to prevent overuse of KERS around a lap.
Typically the battery will hold more charge than a laps worth of harvesting\discharge. So that any unexpected incidents do not leave the driver without their 6s of boost.
In use KERS can be used in several different ways. When lapping alone KERS typically gains 0.45s per lap, although this varies slightly by track. Along with DRS is can boost top speed by 12kmh. As explained the driver uses a pre-agreed amount of boost, decided from simulation work done at the factory before the race. So the planned strategy of KERS usage will be used in practice, qualifying and in parts of the race. However in the race the driver can use KERS tactically to gain an advantage. Drivers are able to use more a KERS boost to either overtake or defend a position. One feature of 2011 along with the Pirelli tyres being in different condition during the race, was the driver’s freedom to alter their racing line and use their grip and KERS to tackle their rivals.

KERS future
KERS continues in its current guise for another two years, then for 2014 along with all new engine regulations there will be a new format KERS. Energy recovery will be from different sources, so the overriding term for the hybrid technology on the car will simply be ERS (Energy Recovery Systems). However KERS will still exist, harvesting energy from braking, but will have a greater allowance for energy stored and reapplied. But, there will also be TERS (Thermal Energy Recovery), which a MGU harvesting energy from the turbocharger. Overall ERS will provide a third of the engines power for some 30s of the lap. No longer will the driver press a button for their KERS boost, it will be integrated in their demand for power from the throttle pedal. The electronics will be constantly managing the Powertrains energy, harvesting and applying energy based on whether the driver is on or off the throttle. In 2014 Powertrains and ERS is set to become very complicated.

Now entering their third year what was Team Lotus and now Caterham F1 have produced their most contemporary package yet. Also in the second year of their partner ship with Red Bull and Renault for the supply of their power train, there will be inevitable comparisons of the CT-01 to the cars from its technical partners. Indeed superficially the car bears some resemblances to the RB7, but the car is indeed the work of the technical team lead by Mike Gascoyne and Mark Smith in Hingham. Where as Red Bull supply the Gearbox\Hydraulics and Renault the Engine\KERS package.

Although the car is clearly wearing 2011 spec wings, vanes and brake ducts, its evident the car is another step forward in design terms for the team.

Three features stand out as different from the 2011 T128; the nose, the sidepods and the roll hoop.

Firstly the nose (Cutting from this months F1Racing magazine) is the first example we have seen of the revised 2012 nose regulations, limiting the front of the nose to a height of just 55cm. However the remaining raised monocoque section between that and the cockpit can be 62.5cm high, so we see the step between these two sections and this is partly softened by the ridged “V” nose. (more detail on the 2012 nose rules)

The sidepods follow the Red Bull template with slim sidepods tapering out at their base. The coke bottle shape streamlines smoothly into the gearbox fairing, there being no cooling outlet from the sidepods themselves, instead the tail funnel acts as the main outlets, while there also appears to be small outlets either side of the cockpit sides.

Amidships we see the all-carbon blade type roll structure from 2011 has disappeared, replaced by a more conventional roll hoop. With part of its structure exposed in the form of the struts supporting the roll structure. Its likely this structure has some metal in its construction. The use of heavier metal in the structure, is offset by the shape being more structurally efficient and probably of equal weight compared to the all carbon blade.

The nose cone is much wider and shallower than in 2011, this being create enough mass within the deformable structure while still meeting the “V” shaped front bulkhead. A new front wing is in development, its likely this will follow the 2011 trend for an endplate-less design with a three element wing meeting the centre section in a curled profile. The raised front section of chassis means Caterham have retained their steeply include front suspension. Interestingly, the bulges on the nose, seem to a reverse twin keel and mount the front leg of the upper wishbone. Around the cockpit opening their appear to be cooling outlets, these aiding cooling allowing much slimmer sidepods. The bodywork aft of this area bulges outwards slightly and sweeps back smoothly around the engine to the tail funnel. In meeting the 2012 regulations the exhausts are tucked in quite low and inboard. The mandatory last 100mm of exhaust being covered by fairings formed into the engine cover. From these pictures its hard to tell how steeply the exhausts are angled at. Therefore its hard to tell if the exhaust effect the flow under the rear wing.

As the sidepods are so slim and there being no low level exhausts, there is a wide expanse of exposed floor. The diffuser sweeps outwards and there is a generous cut out around the rear wheels. The centre section of the diffuser often termed the boat tail is exposed to the airflow. Suggesting the rear impact structure is raised clear fo the floor. This is in contrast to Red Bulls preferred practice of a low rear crash structure. The lowered section probably allows airflow over the floor to pass through the starter motor hole to aid airflow passing up under the diffuser.
By using the Red Bull Carbon fibre gear case, the rear suspension is also largely taken from the Red Bull. Thus it employs pull rod operation for the springs and dampers. However the KERS installation may follow either Red Bulls Pannier style battery installation or the more typical under-fuel-tank installation.

For 2012 we will have a raft of rules changes that will alter the look and performance of the car. For most of the new cars, we will immediately see the impact of the lower nose regulations. Then the big story of 2010-2011 of exhaust blown diffusers (EBDs) comes to an end with stringent exhaust placement rules and a further restriction on blown engine mappings.
Even without rule changes the pace of development marches on, as teams converge of a similar set of ideas to get the most from the car. This year, Rake, Front wings and clever suspensions will be the emerging trends. Sidepods will also be a big differentiator, as teams move the sidepod around to gain the best airflow to the rear of the car. There will also be the adoption of new structural solutions aimed to save weight and improve aero.
Last of all there might be the unexpected technical development, the ‘silver bullet’, the one idea we didn’t see coming. We’ve had the double diffuser and F-Duct in recent years, while exhaust blown diffusers have thrown up some new development directions. What idea it will be this year, is hard, if not impossible to predict. If not something completely new, then most likely an aggressive variation of the exhaust, sidepod or suspension ideas discussed below.

2012 noses

The most obvious rule change for 2012 is the lowering of the front of the nose cone. In recent years teams have tried to raise the entire front of the car in order to drive more airflow over the vanes and bargeboards below the nose. The cross section of the front bulkhead is defined by the FIA (275mm high & 300mm wide), but teams have exploited the radiuses that are allowed to be applied to the chassis edges, in order to make the entire cross section smaller. Both of these aims are obviously to drive better aero performance, despite the higher centre of Gravity (CofG) being a small a handicap, the better aero overcomes this to improve lap times.

A safety issue around these higher noses is that they were becoming higher than the mandatory head protection around the cockpit, in some areas this is as low as 55cm. It was possible that a high nose tip could easily pass over this area and strike the driver.

The front section of chassis will be as high as possible (at 62.5cm) and radiussed into a "V" shape

So now the area ahead of the front bulkhead must be lower than 55cm. However the monocoque behind this area can remain as high as 62.5cm. Thus in order to strive to retain the aero gains teams will keep a high chassis and then have the nose cone flattened up against this 55cm maximum height. Thus we will see these platypus noses, wide and flat in order to keep the area beneath deformable structure clear for better airflow. The radiussed chassis sides are still allowed so we will also see this 7.5cm step merged into the humps a top of the chassis.
Areas below and behind the nose are not allowed to have bodywork (shown yellow in the diagram), so small but aggressive vanes will have to be used, or a McLaren style snowplough. Both these devices drive airflow towards the leading edge of the underfloor for better diffuser performance.

New exhausts

Exhausts must be high up on the sidepod, so cannot blow the diffuser

Having used the engine via the exhausts to drive aerodynamic performance for the past two years, exhaust blown diffusers will be effectively banned in 2012. The exhausts must now sit in small allowable area, too high and far forward to direct the exhausts towards the diffuser. The exhausts must feature just two exits and no other openings in or out are allowed. The final 10cm of the exhaust must point rearwards and slightly up (between 10-30 degrees). Allied to the exhaust position, the system of using the engine to continue driving exhaust when the driver is off the throttle pedal has also been outlawed. Last year teams kept the engine throttles opened even when the driver lifted off the throttle for a corner. Then either allowing air to pass through the engine (cold blowing) or igniting some fuel along the way (hot blowing). The exhaust flow would remain a large proportion of the flow used when on the throttle, thus the engine was driving the aero, even when the driver wasn’t needing engine power. Now the throttle pedal position must map more closely the actual engine throttle position, thus if the driver is off the throttle pedal, then the engine throttles must be correspondingly closed.

Blown rear wing (BRW): The exhausts will blow upward to drive flow under the rear wing for more downforce

Teams will be faced with the obvious choice of blowing the exhausts upwards towards the rear wing, to gain a small aerodynamic advantage, when the driver is on the throttle. These Blown Rear Wings (BRWs) will be the conservative solution and certainly will be the first solution used in testing.
However, it’s possible to be aggressive with these exhaust designs too. One idea is blowing the rear wing with a much higher exhaust outlet; this would blow tangentially athte wing profile, which is more effective at increasing the flow under the wing for more downforce. Packaging these high exhausts may cause more problems than gains. But last year’s exhausts passing low and wide across the floor suffered a similar issue, but proved to be the optimum solution.

A more aggressive BRW raises the exhaust and blows tangentially under the wing profile, which is more efficient

Even more aggressive solution would be directing the exhausts onto the vanes allowed around the rear brake ducts. If avoiding the brake cooling inlet snorkel, the fast moving exhaust gas would produce downforce directly at the wheel, which is more efficient than wings mounted to the sprung part of the chassis. However the issue here would be the solution is likely to be so effective, that it will be sensitive to throttle position and rear ride height. If these issues can be engineered out, then this is an attractive solution.

An extreme but legal solution is to blow the exhaust on the rear brake duct fins creating downforce directly at the wheel.

Wing ride height and Rake
With rules setting a high front wing ride height and small diffusers, aero performance is limited. So teams have worked out how to work around these rules by angling the entire car into a nose down attitude. This is known as ‘Rake’, teams will run several degrees of rake to get the front wing lower and increase the effective height of the diffuser exit. Thus the front wing will sit closer to the track, than the 75mm when the car is parallel to the ground. While at the rear, the 12.5cm tall diffuser sits an additional 10cm clear of the track, making its expansion ratio greater. Teams were using the EBD, to seal this larger gap between the diffuser and the floor. Without the EBD teams will have to find alternative way to drive airflow into the gap to create a virtual skirt between the diffuser and track.
Furthermore teams have also allowed the front wing to flex downwards at speed to allow it to get closer to the ground, further improving its performance. Although meeting the FIA deflection tests, teams are allowing the wing bend and twist to position the endplate into a better orientation, either for sealing the wing to the ground or directing airflow towards the front tyres wake. Both creating downforce benefits at the front or rear of the car, respectively.
One issue with allowing the wing to ride closer to the ground through rake or flexing, is that at high speed or under braking (when the nose of the car dives), the front wing can be touching the ground. This is bad for both aero and for creating sparks, which will alert the authorities that the wing is not its normal position relative to the chassis. So teams are creating ways to manage front ride height. Traditionally front bump rubbers or heave springs will prevent excessively low ride heights. Also the front suspension geometry runs a degree of geometric anti-dive, to prevent the nose diving under braking.

Antidive geometry in the front suspension is one way to reduce pitch under braking

Last year we saw two additional solutions, interlinked suspension, where hydraulic suspension elements prevent nose dive under braking by displacing fluid in a hydraulic circuit one end of the car to the other end, creating a stiffer front suspension set up. This prevents dive under braking, while keeping a normally soft suspension for better grip.
We have also seen Lotus (nee LRGP) use torque reaction from the front brake callipers to extend the pushrod under braking, creating an anti-dive effect and prevent the nose dipping under braking.

An interpretation of the Lotus Antidive solution, using the brake caliper mounting to operate a hydraulic circuit and extend the pushrod (legally) under braking

These and probably other solutions will be seen in 2012 to maintain the ideal ride height under all conditions.

Front end

A three element endplate-less front wing

Towards the end of last year, front end aero design was converging into a set of similar ideas. Aside from the flexible wing option, already discussed above. The main direction was the use of a delta shaped three\four element wing, sporting no obvious endplate. The delta shape means that most of the wings downforce is created at the wing tip; this means less energy is taken from the airflow towards the inner span of the wing, which improves airflow at the rear of the car. Also the higher loading near the wing tip creates a stronger vortex, which drives airflow around the front tyre to reduce drag. Three wing elements are used, each being similar in chord length, rather than one large main plane and much smaller flaps. This spaces the slots between the elements out more equally, helping reduce airflow separation under the wing. More slots mean a more aggressive wing angle can be used without stalling. At the steepest outer section of wing, teams will mould a fourth slot in the flap to further manage airflow separation.
First introduced by Brawn in 2009, the endplate-less design is used as it’s more important to drive airflow out wide around the front tyre, than to purely maintain pressure difference above and below the wing. Rules demand a minimum amount of bodywork in this area, so vanes are used to both divert the airflow and meet the surface area regulations. This philosophy has now morphed into the concept, where the wing elements curl down to form the lower part of the endplate. Making the wing a homogenous 3D design, rather than flat wing elements and a separate vertical endplate.

Arched sections (yellow) of wing, help drive vortices to divert airflow along the car

A feature starting to emerge last year was arched sections of wing. Particularly near the mandatory neutral centre 50cm section of wing. These arched sections created elongated vortices, which are stronger and more focussed than tip vortices often used to control airflow. In 2012 many teams will create these unusual curved sections at the wings interface with the centre section.

Extending the front wing mounting pylons helps to make use of the middle 50cm of wing

Above this area, the pylon that mounts to the wing to the nosecone has been exploited to stretch he FIA maximum cross section to form the longest possible pylon. This forms the mounting pylon into endplates either side of the centre section of wing and along with the arched inner wing sections, help create the ideal airflow 25cm from the cars centreline (known as the Y250 axis).

Pointing a section of front wing profile at a suitable vane on the front brake ducts is one way gain aero performance.

In 2011 Mercedes GP used a section of the frotn wing to link up with the fins on the brake ducts, this created an extra long section of wing.  Vanes on the front brake ducts are increasingly influential on front wing performance and front tyre wake.
Mercedes GP also tried an innovative F-Duct front wing last year. This was not driver controlled, but rather speed (pressure) sensitive. Stalling the wing above 250kph, this allowed the flexing wing to unload and flex back upwards at speed, to prevent the wing grounding at speed. But the effect altered the cars balance at high speed, and the drivers reportedly didn’t like the effect on the handling. I’ve heard suggestions that the solution isn’t planned for 2012.

Sidepods
With so much of the car fixed within the regulation, it’s becoming the sidepods that are the main area of freedom for the designers. Last year we saw four main sidepod concepts; Conventional, Red Bull low\tapered, McLaren “U” shape and Toro Rosso’s undercut.
Each design has its own merits, depending on what the designer wants to do with the sidepods volume to get the air where they want it to flow.

An undercut in the sidepod is one way to drive good flow around the sidepod to the diffuser

This year I believe teams will want to direct as much airflow to the diffuser as possible, Red Bulls tiny sidepod works well in this regard, as does the more compromised Toro Rosso set up. Mclarens “U” pod concept might be compromised with the new exhaust rules and the desire to use a tail funnel cooling exit. However the concept could be retained with either; less of top channel or perhaps a far more aggressive interpretation creating more of an undercut.

Using a slight McLaren "U" shape to the sidepod may still work in 2012

Part and parcel of sidepod design is where the designer wants the cooling air to enter and exit the sidepod. To create a narrower tail to the sidepod and to have a continuous line of bodywork from sidepod to the gearbox, the cooling exit is placed above the sidepod, in a funnel formed in the upper part of the engine cover. Most teams have augmented this cooling outlet with small outlets aside the cockpit opening or at the very front of the sidepod.

The tail funnel (light yellow) is a good cooling outlet method, as it reduces the size of the coke bottle section of sidepod

To let more air into the sidepod, without having to create overly large inlets, teams will commonly use inlets in the roll hoop to feed gearbox or KERS coolers.

Other aero
Even without the exhaust blowing over the diffuser, its design will be critical in 2012.
As already mentioned the loss of the exhaust blowing will hurt the team’s ability to run high rear ride heights and thus a lot of rake. Unobstructed the EBDs exhaust plume, airflow will want to pass from the high pressure above the floor to the lower pressure beneath it. Equally the airflow blown sideways by the rear tyres (known as tyre squirt) will also interfere with the diffuser flow.

The Coved section of floor between the tyre and diffuser will be a key design in 2012, as will cold blown starter holes and trailing edge flaps

Before EBDs teams used a coved section of floor to pickup and accelerate some airflow from above the floor into the critical area between the diffuser and rear tyre. I predict we will see these shapes and similar devices to be used to keep the diffuser sealed at the sides.
Last year we saw teams aid the diffusers use of pulling air from beneath the car, by adding large flap around its trailing edge. So a high rear impact structure raised clear of the diffusers trailing edge will help teams fit these flaps around its entire periphery. Red Bull came up with a novel ideal by creating a duct feeding airflow to the starter motor hole; this improves airflow in the difficult centre section of the diffuser. Many teams will have this starter motor hole exposed by the raised crash structure, allowing airflow to naturally pass into the hole. However I expect some vanes or ducts to aid the flow in reaching this hole tucked down at the back of the car.

Tapered flaps and top mounted DRS pods will be a direction for 2012

DRS was a new technology last year. We soon saw teams start to converge on a short chord flap and a high mounted hydraulic actuator pod. DRS allows the rear wing flap to open a gap of upto 50mm from the main plane below it. A smaller flap flattens out more completely with this 50mm gap, reducing drag more effectively than a larger flap.
As drag is created largely at the wing tips, I would not be surprised to see tapered flaps that flatten out at the wing tip and retain some downforce in the centre section. Teams may use the Pod for housing the actuators, although Mercedes succeeded with actuators hidden in the endplates. Having the pod above the wing clears the harder working lower surface, thus we will probably not see many support struts obstructing the wing.

Structures

Variations on William low line gearbox and differential will be followed for this year

Super slim gearboxes have been in vogue for many years, Last year Williams upped the stakes with a super low gearbox. The normally empty structure above the gear cluster was removed and the rear suspension mounted to the rear wing pillar. Williams have this design again for 2012, albeit made somewhat lighter. With the mandatory rear biased weight distribution the weight penalty for this design is not a compromise, while the improved air flow the wing is especially useful in 2012. So it’s likely the new cars will follow the low gearbox and low differential mounting in some form.

Rear pull rod suspension will be all but universal this year

A lot is said about Pull rod rear suspension being critical for success. In 2011 only a few teams retained push rod rear suspension (Ferrari and Marussia). I would say the benefits between the two systems are small; pushrod trades a higher CofG for more space and access to the increasingly complex spring and damper hardware. Whereas pull rod benefits from a more aerodynamically compact set up and a lower CofG. I still believe either system works well, if packaged correctly.
At the front it’s unlikely pull rod will be adopted. Largely because the high chassis would place a pull rod at too shallow an angle to work efficiently. Regardless the minimum cross section of the footwell area, discounts any potential aero benefits. Leaving just a small CofG benefit as a driver to adopt this format.

Undercut roll hoops with internal metal reinforcement will be a common feature to drive airflow to the rear wing

Most teams now use a metal structure to provide strength inside the roll hoop; this allows teams to undercut the roll hoop for better airflow to the rear wing. Even though last year two teams followed Mercedes 2009 blade type roll hoop, for Caterham at least, this isn’t expected to return this year. Leaving the question if Force India will retain this design?

Electronics and control systems
The 2012 technical regulations included a large number of quite complex and specific rules regarding systems controlling the engine, clutch and gearbox. It transpires that these are simply previous technical directives being rolled up into the main package of regulations. Only the aforementioned throttle pedal maps being a new regulation to combat hot and cold blowing.

While I still try to crack that deal to make this my full time job, I do this blog and my twitter feed as an aside to my day job. In the next few weeks I plan to attend the launches and pre-season tests. If you appreciate my work, can I kindly ask you to consider a ‘donation’ to support my travel costs.

Controls for the throttle, antistall and gearshift have all been clarified, such as a requirement to stay in first gear until 100kmh. I can only speculate some teams were improving their launches, by controlling the clutch off the line under the auspices of the antistall and gearshift rules. I will research this further to see if this is the case.

FIA Website

Technical Regs (PDF)

Sporting Regs (PDF)

3.7.9 Bodywork in front of the front (A-A) bulkhead must not be higher than 550mm, as outlined in my previous post

3.12.6 The manufacturing tolerance for the floor is reduced to 3mm (from 5mm)

4.2 Fixed Weight distribution confirmed for 2012 & 2013

5.5 Drivers torque demand via the accelerator pedal more tightly defined

5.8 Exhaust position confirmed as outlined in my previous post

5.19 Anti stall systems more tightly defined

8.6 All driver buttons and controls to be via dedicated input to the ECU. The Drivers use of these controls must logged for FIA inspection

8.11.1 Five additional sensors for data logging can be fitted for P1 and P2

9.2.5 Clutch control is more tightly defined

9.8.1 Clarification of multiple driver gear shift requests

9.8.2 At the race start and at pit stops, first gear must be used until the car is travelling 100kmh

9.8.4 Clarification of time allowed for shift requests to be started and completed

9.8.5 Track position cannot be used as an input the gearshift control

10.5.3 Uprights cannot extend too far inboard, similar to brake duct dimensions

12.7.3 Only tyre heating blankets may be used to warm the tyres

12.8.4 Wheel guns can only run on Air or Nitrogen, not Helium

Making this early debut more difficult for this year are the revised rules around crash testing. Typically teams have passed their final crash tests in the days before the first race, but now teams have to have passed all these tests before they can start testing. With initial crash tests being carried out now and continuing into January, any failure of a structure to pass its test first time may impact on the teams ability to attend the first test with their new car. This process of crash testing is a form of homologation, but unlike 2009, teams are free to homologate and crash test new structures at any point. So some teams may opt to accept a heavier component that will pass the tests in order to go testing and have the race-spec lighter pass ready for Melbourne.

Tests
Jerez Website
Feb 7th – 10th

Barcelona1 Website
Feb 21st – 24th

Barcelona2 Website
Mar 1st – 4th

Mugello Website
May 1st – 3rd

Car Launches
Red Bull: Launch 6th Feb 1pm (GMT) online, 1st test at Jerez
McLaren: Launch 1st Feb 11am (GMT) at Woking, 1st test at Jerez
Ferrari: Launch 3rd Feb at Maranello, 1st test at Jerez
Mercedes AMG: 1st test Barcelona1
Lotus: Launch Feb 6th, 1st test at Jerez
Sauber: Launch Feb 6th, 1st test Jerez
Force India: Launch 3rd Feb 9am (GMT) at Silverstone, 1st test at Jerez
Toro Rosso: Launch & 1st test at Jerez
Williams: 1st test at Jerez
Caterham: Launch online 26th Jan & 1st test at Jerez
HRT: Plan to test new car at 1st Barcelona test
Marussia: Plan to test new car at 1st Barcelona test

This video was kindly supplied by John Travis Technical Director of Trackcreate Ltd , the designer of the A1GP car along with his team A1GP Technology Ltd and is also one of the partners in RaceStaff.

The A1GP Ferrari car was built to satisfy the FIA 2004 F1 crash test regualtions. Thus the tests were carried out the Transport Research Laboratories (TRL). For this test, the complete monocoque and nose cone assembly must be complete and fitted to the test sledge weighing a total of 780Kg. To make the test representative, the fuel tank must be filled with water and a crash test dummy wearing seat belts must be installed. Travelling at just over 30 mph at the point of impact, the driver must not be a peak deceleration greater than 60g and the monocoque\trolley must not average more than 40g. As well as this the monocoque itself, seat belts and fire extinguisher must be intact after the crash. Its clear to see that at this rate of deceleration the driver and seat belts display alarming elasticity, although this is part of the mechanism to reduces the loads and potential for injury.

16.2 Frontal test :

All parts which could materially affect the outcome of the test must be fitted to the test structure which must be solidly fixed to the trolley through its engine mounting points but not in such a way as to increase its impact resistance.

The fuel tank must be fitted and must be full of water.

A dummy weighing at least 75kg must be fitted with safety belts described in Article 14.4 fastened.

However, with the safety belts unfastened, the dummy must be able to move forwards freely in the cockpit.

The extinguishers, as described in Article 14.1 must also be fitted.

For the purposes of this test, the total weight of the trolley and test structure shall be 780kg and the velocity of impact 14.0 metres/sec.

The resistance of the test structure must be such that during the impact :

- the average deceleration over the first 150mm of deformation does not exceed 5g ;

- the average deceleration of the trolley does not exceed 40g ;

- the peak deceleration in the chest of the dummy does not exceed 60g for more than a cumulative 3ms, this being the resultant of data from three axes.

Furthermore, there must be no damage to the survival cell or to the mountings of the safety belts or fire extinguishers.

As part of the RaceStaff sponsorship of ScarbsF1, We will have more videos of the A1GP car testing next month.

LRGP have also been one of the teams racing hydraulically interlinked suspension and have looked at other ways to legally alter the suspensions performance. It seems this work has lead to the discovery of a new form of Inerter, primarily using fluid for the Inerter effect. This new development has been termed by the team a “Fluid Inerter”.

A cross section of the patented Fluid Inerter

The intellectual property rights to this development have been safeguarded by Patent, allowing the details to be freely accessible in the pubic domain (the source for the picture at the top of this article). My attention was drawn to this development by Italian Mechanical Engineer Rodolfo De Vita, a specialist in Torsional Dampers and Dual Mass Flywheels (DMF).

Background
Becoming ever more complex the suspension in an F1 car has a number of devices to counter loads fed into the chassis, in order to maintain the ideal conditions at the tyre contact patch. We understand the role of springs and dampers, but there remain other spring effects within the suspension system, not least from the high profile tyres. Their spring effect goes undamped and hence is largely out of the control of the teams in setting up the car. Being able to counteract these uncontrolled forces in a suspension will allow the tyre to main better contact with the ground for more consistent grip. In 2003 Cambridge Universities, Dr Malcolm Smith proposed a mechanical method of controlling these loads via the Inerter. McLaren took up this idea and tested the idea in 2004 then went on to race an Inerter in 2005.
In size and construction the Inerter looks like any other damper. Being placed in the same position as a Heave Damper it was well hidden and unknown to most people. Until the “Spygate” saga in 2007, when the design was referenced as both the “J-Damper” and “a Damper with a Spinning Mass”. It wasn’t until May 2008 that I was able to understand and expose the details of the Inerter concept, publishing its details in Autosport.com (subscribers only http://www.autosport.com/journal/article.php/id/1554 ). Co-incidentally this article is cited in the patent documentation!

A Mechanical Interter

An Inerter can be configured in two ways: a linear and a rotary format. In both guises the device uses a toothed drive to spin a mass. Likened to the same effect as a bicycle bell, the load fed into the bells lever is dissipated by the spinning element. In F1 teams use a cylindrical mass screwed onto a threaded rod inside a damper body. One end of the rod is affixed to one side of the suspension and the damper body to the other side of the suspension. Reacting to the acceleration of the suspension, the Inerter absorbs the loads that would otherwise not be controlled by the velocity sensitive conventional dampers.

The Renault 2006 Front Tuned Mass Damper (TMD) - Copyight: Craig Scarborough

The Inerter predates Renaults TMD, which aimed to achieve the same effect. With the TMD a weight is suspended on spring to offset the same forces being fed into the chassis as the Inerter. Renault first raced the TMD in 2005, its discovery by Giorgio Piola around Monaco of that year; both forced a development race and an enquiry by the FIA. It was subsequently banned on what proved to be false grounds. The FIA citing a movable aerodynamic effect as the reason for its ban.
Unaware of its effect on the contact patch, I initially saw the device as a means to prevent the front wing pitching downwards when braking. The inertia of the suspended mass keeping the nose from pitching downwards during the initial braking phase. This I thought would prevent the car from being pitch sensitive. Despite a lengthy court room case, this “aero” function was upheld as the reason for the ban of the device.
Ironically the McLaren was using the Inerter at the time, and despite it being used for the same function was not banned and remains legal and in universal use to this day.

LRGP’s Fluid Inerter Concept
Reading the detail of the LRGP patent, it’s clear this was at least partly a surprise discovery. The Patent states the discovery was “based on lab testing of another hydraulic suspension device”, when it was found that the effect of the fluid within the system “has a very significant inertia effect”.
I would suspect this discovery was made during the development of the linked suspension system. Where fluid lines are used to link the suspension in a similar manner to the Mercedes system I detailed earlier this year (http://scarbsf1.wordpress.com/2011/10/17/mercedes-innovative-linked-rear-suspension/). Perhaps the longer fluid lines to link front and rear suspension provided the discovery, rather than the very short left to right linking pipework. I understand Renault have had hydraulically linked suspension on the car since at least 2009.
With this insight LRGP have proposed a Fluid Inerter using both the inertia of the fluid and a spinning mass. By making the Inerter device more like a damper, where by a damper rod displaces fluid; this fluid is then piped into a circuit to spin the mass. There by both effects can be created. It is the inertance of the fluid that differentiates the LRGP patent to the conventional Inerter proposed by Dr Malcolm Smith.
Inertance is a new term and I’ll quote the patent for LRGP’s explanation of the effect.
“Hydraulic fluid inertance means” concerns an arrangement in which the presence of a hydraulic fluid provides an inertance, where inertance is a measure of the fluid pressure which is required to bring about a change in fluid flow rate in a system. Between the terminals this translates to an inertial force which resists acceleration.
LRGP found that the fluid used was critical to the efficiency of the design. In particular to make it effective for the lightweight and small packaging volume required to make the device work within the tight confines of an F1 footwell or gearbox. Needing to be incompressible and low viscosity, they have proposed several fluids, such as water and oil, but the preference appears to be for Mercury. Although a metal, it’s liquid at ambient temperatures and very dense. This means smaller fluid lines filled with mercury will provide the necessary inertance, compared to larger amounts of less dense fluids. Passing from one chamber in the damper body via the fluid line to the other chamber, the detail design of the length and diameter of the fluid lines are key in creating the correct tuned inertance effect. Just “1 to 50g” of fluid is required to get the desired effect. The range of inertial reaction is quoted as “10 to 500kg, which is a typical range required in Formula One racing cars”.
As a side note McLaren decouple this inertial reaction force into different measured units. Rather than Kg of Inertial force, McLaren use the term “Zog”, this allows them to hide the actual units set up on their Inerter.
Renault suggests winding the lines around the damper body as one solution for the packaging of the fluid circuit. Additionally a valve or shim stack in the damper rod would also alter the amount of fluid displaced, to further tailor the Inerters effect.
With Mercury having a high coefficient of thermal expansion, the patent suggests using a relief valve emptying into another chamber is used to ensure the system has a constant volume of fluid.
Clearly the emphasis is on the fluid to provide the inertance effect, the patent citing a minimum 50%, up to as much as 90% of the inertance coming from the fluid.

In Detail

The device uses the left hand casing as the fluid cylinder & the right hand casing for bump rubbers

Not only does the Patent contain the conceptual information on the Inerter, but also detailed cross sections. I have simplified these to explain the Inerters construction. LRGP have been able to condense the entire solution into a single self contained component, which fits into the same volume as the conventional Inerter.
The device is made up of a main body and a damper rod. The main body split into left and right sections bolted together. The left hand casing forms the cylinder, not only contains the fluid, but also channels machined in the outer casing form the fluid lines. Such that no external pipework is required. The right hand casing allows the damper rod to pass through and also houses bump stops to prevent the device bottoming at the end of its 16mm of bump travel or 23mm of droop travel. In total the device is just 220mm long (eye to eye).
In cross section we can see the casing is a complex machined part. With the right hand chamber formed with bushes, seals and endplates to create the cylinder for the damper rods to pass through. The damper rod along with its shim stack valve pass through the cylinder like piston as the suspension compresses and rebounds. The mercury within is displaced and passes through channels into the channels machined into the wall of the body.

Installation

The Inerter (yellow) is mounted between the rockers

LRGP provide a diagram for the Inerters mounting. This being a typical position between the pushrod rockers. No doubt a similar mounting is found between the rear pull rod rockers. Externally it would be hard distinguish the Fluid Inerter from a Mechanical version. Albeit the Renault front bulkhead design shows almost nothing of the Inerter inside the footwell. The steering rack and anti roll bar getting in the way of the small aperture inside the front of the monocoque. Thus we cannot be clear if the device has raced.

Benefits
One benefit is the technology is proprietary to LRGP and not used under license via Penske or Dr Malcolm Smith. Thus LRGP are free to use and develop this technology freely.
I couldn’t state whether the Fluid Inerter has any compliance benefits over a mechanical one. Perhaps it’s easier to tune via the shim stack in the damper rod, rather than the fixed specification of the mechanical Inerter. Equally it may be easier to maintain, teams needing to strip clean and re-grease their Mechanical Inerters frequently to maintain their smooth operation.
It seems one advantage to this device might be lightweight. The tiny amount of fluid required would be lighter than an equivalent spinning mass. As Inerters tend to be mounted relatively high a weight saving will aid CofG height, as well as ballast placement.
One negative issue is that Mercury is a hazardous material. Considering the unit is positioned ahead of the driver’s legs, any mercury leakage as a result of a major accident will only complicate the health issues for the Driver and Marshalls. I am not aware of Mercury being specifically restricted by the FIA approved material list. Although with just a few CC’s of the liquid contained within the cylinder, this might not be regarded as an issue by the FIA.

Conclusion
However the team came across this solution, it is a new direction for Inerter development. The solution is totally legal, as set by the precedent of the mechanical Inerter being allowed to race, even when the TMD wasn’t
It will be interesting other teams come forward with new Inerter or linked suspension solutions. The only problem is few teams patent their design to allow us such insight to their design.

A view of the outer casing

…

A cross section of the Inerter

…

An exploded view of the parts

More references on Inerters

http://www.montefiore.ulg.ac.be/doc/smith09.pdf

http://www.ieeecss.org/sites/ieeecss.org/files/documents/IoCT-Part2-14FormulaOne-HR.pdf

The Rotary damper has been an innovation that has recently come and gone in F1. Typically F1 cars use Linear\telescopic dampers. However, in 2003 Sachs Race Engineering developed a Rotary version of a classic monotube damper for Ferrari. This was a tidier solution for packaging the dampers at the rear of the car. Since 2003 several teams have used Rotary dampers, Toyota, Midland and most notably Brawn GP. Who won the 2009 championship with these fitted at the rear of the car. I have recently come across a Rotary damper as fitted to the Midland car in 2006 and thus we have the chance to look into the detail of this development. I’ve also been in touch with two of the designers who have raced this device and they have given us some unique insight into its use.

Firstly John McQuilliam, who is now Designer for Marussia, but back in 2006, was the designer for Midland F1 (previously Jordan, latterly Spyker and Force India). The Midland M16 was the first of the teams’ cars to exploit Rotary dampers, as McQuilliam explains “I remember we were working with Sachs, as we had their Clutches on the car at the time. The Ferrari had Rotary dampers and it looked to be such a neat installation, we wanted to do something similar “. But this was not a total success, as their use on the Midland was short lived as they were replaced mid season with Linear dampers.

Secondly we have insight from the ex-Brawn Designer Jorg Zander, now running his own consultancy (http://jz-engineering.com/). As Honda were leaving F1 and the Brawn GP team was created, due to the Honda link the team had been using Japanese Showa dampers, but Zander was persuaded to switch to a Rotary design. As Zander recalls “Showa did a brilliant job and they would have provided us with continued support, but my boss was keen to go down the Rotary damper path with Sachs”. He adds that “the car still won the championship!”. Along with the Ferrari wins during their use of the Sachs Rotary damper, it’s clear that the technology has had a lot of success in F1. But it is still blighted by a reputation of being a troublesome technology.

Linear dampers
A conventional Linear damper is made up from a cylindrical body in which a damper rod slides in and out of (much like a bicycle pump). A valve at the end of the damper rod passes through the inside of the cylinder which is filled damper oil and the oil passing through the vales controls the rate of movement of the damper. Being cylindrical it is easy to machine in a lathe and oil is kept in place with simple circular seals.
The Dampers are installed on the car by one end being secured to the gearbox case, the other end to a rocker which re-orientates the movement from the pushrod into the movement of the damper. The rocker can be made up of several levers splined to a single shaft and requires several bearings to make the suspension movement friction free. This amasses into quite a lot of separate components which all need space to fit in.

Rotary Damper Anatomy

A top view of the Rotary Damper

Essentially the Rotary damper rotates the axial movement of the Linear damper into a Rotary movement. All the components have the same function, they just move in a different orientation. Thus the damper body is deep “keyhole” shape and the damper rod (known as the vane) rotates in the body, the vanes arm sweeping through a small angular rotation in the keystone section of damper body. The damping valves are placed in the face of the damper vane and work in exactly the same manner as a Linear damper.

Obviously the shape is the biggest difference and manufacturing the damper is far harder due to the fact that the parts have to be CNC milled and not spun in a lathe.

Its clear to see how the Vane moves inside the Casing to provide the Damping effect

Damper body

A view inside the cavity of the Damper Body

We can see the damper body is a robust metal housing machined from solid. Open on one side to allow the damper vane to be installed, there is a closing plate sealed with an “O” ring and 13 small bolts. To allow the damper vane to pivot the body features two bearings and seal arrangements, one on the closing plate the other is the main housing.

Damper body closing plate, with integrated Anti Roll Bar link mounting

As the housing also acts the suspension rocker, there are also elements machined into its outer face to accommodate this function. Firstly the housing acts as the rocker linkage, so a rocker arm is part of the machined shape. One of these eyes in the rocker will mount the heave damper and the other eye has bearing to accept the pushrod. Showing the packaging efficiency of the Rotary damper a further spherical bearing is fitted to a machined section of the cover plate. This accepts the Anti Roll Bar linkage. Thus for the Midland, no further suspension elements need to be fitted to anything but the damper housing. In the case of the all F1 Rotary dampers, the damper body rotates and the damper rod is fixed to the gearbox (via splines). As one part moves and the remains static, the vane moves through the oil filled cavity, the reaction force of these two parts creates the damping effect. To allow the damper body to rotate in the gearbox, two bearing surfaces are machined into the outer face of the housing and cover plate.

One additional external feature is machined into the damper body, a single damper valve. I believe this is a valve to compensate for the effect of heat on the volume of oil inside the casing. The valve offsets the thermal expansion of the oil to ensure there is a constant volume of oil within the damper cavity.

Damper vane

DLC coated Damper vane, the damping valve being bolted into the face of the arm

Inside the damper body sits the damper vane. This is a highly finished and possibly DLC coated component. Even when degreased this part had the feel of a lightly oiled component. The friction reducing coating being there to reduce the friction created by the vane moving inside the housing. Again machined (as most F1 parts are) from solid, the damper vane is formed of two shapes.
Firstly, the spindle that sits in the bearings that allows the arm to the rotate. One end of this spindle has splines machined into it.
Then secondly a flat plate shape is formed into the vane, this is the equivalent of the Linear dampers damping rod. This arm needs to be a close fit to the damper cavity in order to accurately control oil for the damping effect. It’s the edges of this arm that need to be sealed against the housing. A single square edged seal is fitted into a machined groove around the periphery of the vane. There are also four friction reducing pads (two on each side) to aid the movement of the vane against the body.

The three sides of the vane have a seal and friction reducing pads

Providing the damping effect the damper valve is a simply circular shim stack arrangement fitted to hole machined into the vanes face. This valve set up is almost identical to the set up used on the end of a Linear damper. This is perhaps the only aspect of the Rotary damper that directly echoes a Linear set up.

Installation

When installed on the gearbox the damper is clearly visible

As already alluded to, the Rotary damper is fitted to the gearbox casing and forms both the damper and the rocker. The damper vane slides into splines machined into the gearbox casing and a bearing locates on the bearing surface of the cover plate. Then another bracket fits to the rear of the gearbox to locate the rear bearing and secure the damper in place. The torsion bar passes through the damper engaging in splined in the spindle of the damper vane and also on the front face of the gearbox. Splines on the protruding section of the damper body are probably for the preload adjuster arm.

The Heave Spring and Anti Roll Bar are also mounted direct to the Damper

The pushrod passing up from the lower wishbone fits to the rocker, as does the heave spring\damper which sits over the top of the damper to attach to the other side damper. One end of the anti roll bar attaches to each spherical bearing and then the installation is complete.

Pros and Cons of Rotary Dampers
As explained the main benefit is the packaging of these units. Typically Linear dampers are operated by rockers and the dampers are then either laid across the top of the gearbox or sit vertically (requiring a recess in the top of the gearbox case). Either option carries complications in the cars structure or aero. With a Rotary damper the unit forms both the rocker and the damper and takes up far less volume.

As the damper vane permanently sits inside the casing, as the vane sweeps through the radial movement, no oil displaced. This is described a constant volume system. Unlike a monotube damper where the damper rod displaces fluid inside the damper body. This requires a method to offset the movement of the excess fluid. Typically separate nitrogen charged cylinder is used, the gas is compressed by the displaced fluid. But this in itself creates a small spring effect inside the damper. Other methods include the though rod damper, whereby the damper rod passes through both ends of the damper body, thus displacing no fluid. However through rod dampers do require additional seals and this creates some additional friction in the design.

Other key benefits of the simpler Rotary design are weight reduction, with fewer parts the 950g damper with its integrated rocker is lighter than a conventional damper and separate rocker set up. John McQuilliam confirms “We did achieve a weight saving over the conventional layout when you consider the damper, its drive arm and reaction bracket.” McQuilliam goes to on to highlight its packaging and resultant aero benefits “also the packaging is easier, without finding a volume for the damper. Akio Haga who is now alternating chief designer at Force India was laying out the rear suspension back then and we had a few different lay outs, mainly to try and keep the mechanicals out of which ever area the Aero was telling us was most important”.
With there being less parts to be splined together and less bearings in the Rotary design is also stiffer and suffers much less from slop. Jorg Zander explains “the good side of the Rotary damper is that because of the rocker integration, the system is very stiff and direct, so there is little losses due to backlash in linkages, ball joints, etc. which meant it had a good high frequency response”.

So with the damper being a constant volume design, structurally stiff, lightweight and easy to package why has it not become the norm for F1 suspensions?

There is a simplistic argument bandied about that the damping effect is the reason they do not work so well. Neither designer suggested this was the case to me, although at the time McQuilliam did suggest to me it was a factor, but corrected himself with hindsight “I think the damping was actually reasonable”. McQuilliam continues to highlight a more specific deficiency in the Rotary design, “there is a much more complicated sealing arrangement in the damper, adding stiction”. Stiction is one of the enemies of the suspension designer, a mix of terms meaning “sticky” “friction”. This is seen as initial friction, then smoother running. This non Linearity of response is hard to design out. Where as the inherent spring rate added by a gas charged damper can be considered in the overall suspension spring rate, stiction cannot. Zander also echoes this issue “However, the downside is that due to the high internal pressure, the hydraulic seals had to have reasonable preload, which induced a large amount of friction and hysteresis”. This internal pressure also lead to structural issues, the Ex Brawn designer tells me “the high internal pressures caused local deformation of the housing, as well as the vane, this lead to increased friction and pretty inconsistent damping characteristics. Initial developments started with Aluminium, then Ti and steel options to gain stiffness to reduce the issues caused due to deformation. The Midland Damper that I have appears to be titanium. This was an earlier design compared to the Sachs dampers run on the Brawn in 2009. It is possible to see the ribs machined in to the casing to reinforce the device from deformation.

Another argument quoted in the press is the small size of the damper, which results in a lack of oil or radial movement. I removed some 75cc of fluid from the damper and the damping chamber was quite large. The limited radial movement was not seen to be a major problem, being taken into account in the rocker sizing, although both designers point out it still had to be factored in. Zander explains “The angular displacement wasn’t so much of an issue in 2009 and in previous years, but with the heavier fuel loads from 2010 that should be something to be considered.” Seeing as the 2009 Brawn BGP001 was succeeded by the Mercedes W01, it’s interesting to note the latter went back to Linear dampers.

Away from the technical argument of Rotary over Linear there was one other factor which perhaps underlines the less publicised aspect of the designers’ role, budgets! But when we recall that Midland and Brawn were both teams managing a tight budget, this last issue makes sense. Both designers highlighted price as one of the major issues of the Rotary damper. McQuilliam starting by saying “They were mighty expensive, so not good value for money for the weight saving”. Zanders more recent recollection of the Brawn days provides this insight “I think a bigger argument against it for some teams, were the cost of such a Rotary damper. Depending on the specification, it was in the region of about €15.000 per piece”. With these being sealed dampers for each set up, a pair of dampers (€30,000) would be on the car and a multitude of other dampers pairs in the pits, each set up for different damping characteristics.

Conclusion
Clearly the stiction and internal stiffness issues need to be addressed with the design. Evolution via detail design has overcome similar issues with Linear dampers, so presumably the same could be resolved for Rotary dampers too.
The cost issue still remains; inherently they are a complex and high precision part. Where as turning on a lathe produces the correct finish for a Linear damper, careful milling operations are required for the damper body of the Rotary damper, which will inevitably make this an expensive part to produce. No doubt more teams using the damper would drive the price down.
It’s interesting to note that the Sachs Race Engineering website no longer details Rotary dampers as part of their range. Instead conventional Linear dampers and a Through-Rod version of the same, form the basis of their product range and their current Formula1 teams use these Linear format dampers.
Given the choice between Rotary and Linear, Zander sums up the decision well “I would at the current stage of damper technology development prefer Linear dampers over Rotary ones. The friction can be controlled in a better way and problems like cavitation are well understood and do not cause any issues in contemporary Linear damper designs. Also the flexibility with Linear damper designs is much wider, considering systems like: frequency depending damping, high & low speed damping, drop off characteristics (blow by valves, pressure relief valves)”.
Perhaps the Rotary damper will be explored in F1 again at some point, but for now the Linear damper is the sole solution in F1.

Image via Williams F1

Last weeks Young Driver Test was the first chance for teams to try exhausts systems designed to the revised 2012 rules. Next year teams will have to place the exhaust exits in a specific region of the car, with further restrictions on the pipes shape and angle. These changes have been introduced to ban the blowing of the diffuser for aerodynamic gain. While I have detailed these rules previously (http://scarbsf1.wordpress.com/2011/10/26/2012-exhaust-position-and-blown-effects/), we can start to look at what the teams have been doing in Abu Dhabi.

Three teams brought revised exhausts, most notably Williams who ran their exhaust in all three days of the test, while Mercedes did less running with their interim set up and Ferrari tried a non legal exhaust on just one of the testing days.

Williams

IR cameras point upwards towards the wing and pods on the wing house sensors (Image via Williams F1)

Shunning any running with an Exhaust Blown Diffuser (EBD), Williams ran in Abu Dhabi with an exhaust positioned within the correct area and orientation as demanded by the 2012 rules. Their exhaust is a simple interpretation of the new rules, with the exhaust placed close to the cars centreline and as rearwards as possible. Most interestingly the exhaust is tipped up at the maximum 30-degree angle. This positioning suggests the team are trying to blow the centre of the underside of the rear wing. While I have proposed more radical solutions in my previous article, this does show that teams are to look at blown rear wing effects, as opposed to purely aero neutral exhaust positions. Exiting the exhaust pipe at great speed and temperature, the exhaust plume will hit the underside of the rear wing. This would have the effect of speeding up the airflow under the wing decreasing pressure and creating more downforce.

Williams Exhaust is low and rearward within the legality zone (yellow) and points upwards at a max of 30-degrees

However this effect is more complex than a simple jet of gas hitting the rear wing. Gordon McCabe’s Blog (http://mccabism.blogspot.com/2011/10/exhaust-blown-diffusers-in-2012.html) highlighted some research by Prof. K. Kontis & F. L. Parra from the University of Manchester on the effect of exhaust gasses on an F1 car. They found the exhaust plume passing at an angle out into the airflow created its own drag and moreover was bent backwards by the airflow at greater speeds. When this theory is applied to the Williams set up of a steeply inclined exhaust pointed towards the wing suggests some very interesting effects come into play. Firstly at lower speed the exhaust plume (jet) will be far stronger than the flow over the car. Thus this jet passes upwards through the crossflow over the car, will reach the rear wing to create more downforce.

Jet in Crossflow - low speed: unimpeded the exhaust plume blows the rear wing

At lower speeds the jet obstructing the crossflow will create drag and there will be drag induced by the greater rear wing mass flow, but being at lower speeds this drag will not be detrimental to aero performance. Then at higher speeds when the crossflow over the car has more energy the exhaust jet will start to bend backwards. Most likely moving the jet away from blowing the wings under surface. Thus the blown rear wing (BRW) effect will reduce, the car will lose some downforce and the drag induced by the blown effect will also reduce. Thus at higher speeds the car will shed drag, further boosting top speed.

Jet in Crossflow: High Speed - the faster airflow over the car bends the exhaust plume downwards away from the wing

Williams Abu Dhabi Test exhaust is not a clear sign that they will have this exact positioning for 2012, but the test will have proven the blown effect and just as importantly provided data on the heat passed over the rear wing. It was clear that the rear wing was set up with numerous sensors for vibration, heat and pressure measurement. Many of these sensors were within the rear wing flap itself, the shear number of sensors run on the wing required two aerodynamic pods mounted to the rear wing endplate to house the wiring to send the data back to the onboard data-logger. Additionally Williams ran several different kind s of thermal cameras, mounted to the rear crash structure and pointed upwards looking at the underside of the rear wing. This would not only provide actual temperature measurement, but also highlight which areas are being blown by the exhaust, somewhat like a thermal flow-viz test.

Mercedes

Another one of the teams late to the blown diffuser in 2011 and in particular blowing the outer section of floor by the rear wheel, Mercedes also tried a non-EBD set up in Abu Dhabi. According to earlier comments by Ross Brawn on autosport.com (http://www.autosport.com/news/report.php/id/96276), the Mercedes test exhaust was not a definitive 2012 set up “”The car will be testing next week with our first interpretation of what the regulation will be.”, but merely a revised exit location to remove the exhausts effect from the rear ends aerodynamics, “This is compromised because we’re fitting it around the existing car, but we’re removing the effect of the blown exhaust to see how the car will work without that.”

The set up that Mercedes tested with was similar to Williams with the exhaust outlet focussed towards the inner\rear of the regulatory box it needs to sit within. Flanked by bodywork the exhaust did not appear to be as steeply inclined as the Williams set up. Reinforcing Brawns comments about removing the blown effect.

Pictures in F1talks.pl gallery http://www.f1talks.pl/2011/11/17/ostatni-dzien-testow/

Ferrari

Like Mercedes Ferrari run an alternative exhaust on the last day of the test. However unlike these previously two teams they did not fit a 2012 spec exhaust. Instead the cars left-hand exhaust was routed dramatically sideways to exit ahead of the rear tyre. This set up would not be legal either in 2011 or 2012, but was probably a simple to completely remove the blown effect from the rear of the car. With the right hand exhaust apparently in its normal EBD set up, the team would be able to measure the difference in pressure left to right to access the effect the exhaust is having. While a large part of development for 2012 will be aimed at getting the exhaust to do some useful work elsewhere eon the car, such as a blown Rear Wing (BRW), the team salsa need to get the diffuser and rear brake ducts working without the artificially accelerated airflow blowing over the from the exhaust. As the test exhaust does not fit into the current regulations this test would be the one place where they could do this, with permission to run such an exhaust being unlikely for a Friday practice session. So although preparation is underway for their exhaust development, Ferraris plan for their 2012 remains hidden.

Ferrari: A Chamber has been added to the Exhaust system (yellow)

One area of Ferraris exhaust development that has recently been exposed is the exhaust chamber. These devices have been rumoured for many months. Most of the rumours attributed to Mercedes engined teams, although no evidence has appeared of the system on any of their three teams cars. As reported by Giorgio Piola at the Abu Dhabi race, Ferrari had this system in place for the Grand Prix and the system remained fitted for at least part of the test. What at first appears to be another exhaust outlet joined to the secondary exhaust pipe, is in fact a closed ended pipe. This picture of the exhaust removed from the car (http://www.f1talks.pl/2011/11/17/ostatni-dzien-testow/?pid=7210 via F1talks.pl\Sutton Images), shows the large extension, which acts as a pressure accumulator when the exhaust is blowing. Then when the driver is off the throttle the pressure built up in the chamber is release, which smoothes the blown diffuser effect between full and part\closed throttle.

When on the throttle the chamber is pressurised along with the exhaust system

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When off the throttle the chamber maintains some exhaust flow

Similar systems were common on Japanese 2-stroke motorbikes in the eighties, albeit placed on the inlet side of the engine (often termed ‘boost bottles’), Fords WRC car also featured a chamber on the inlet side for similar effect.

This system works on the backpressure created within the exhaust. It’s worth noting Ferrari have recently switched to the nozzle type exhaust outlets, these being narrower in cross section to that of the main exhaust pipe. Most probably these nozzles work to increase backpressure to smooth the exhaust plume at different throttle openings. Just as interesting is the switch of the Mercedes powered teams to nozzle type exits mid season, suggesting the exhaust chamber rumours may be true. It would be logical to assume that the back pressure created within the exhaust both by the nozzles and the chamber would affect top end power. But any time loss being made up by the less senstive aerodynamics.

In some respects this exhaust chamber is similar to what appeared to be a one-way exhaust valve fitted at several GPs this year. The belief being that the exhaust valve allowed the exhaust to suck in air when the driver was off the throttle, to maintain exhaust flow to the diffuser. This being a mechanical alternative to the off throttle mappings (Hot Blown\Cold Blown), which were to be banned mid season. There appears to be a move to again enforce engine mapping restrictions for 2012, so the teams will need to find ways to smooth the exhaust plume over the bodywork. But this one-way exhaust valve will be expressly banned under the 2012 Exhaust Regs. So the exhaust chamber solution appears to be a design what will become present on the many cars exploiting blown exhaust effects in 2012.