Whenever an F1 car runs on track, the team will have planned what parts are fitted and the set up of every facet of the car. Now over a year and a half old and with an even older car, this set up sheet appeared on the Lotus Media site. It was from Kimi Raikkonen’s debut test at Jerez for the team in a R30 (from 2011). It shows some of the set up detail that the teams go into. This also gives us some insight into the spring\damper configuration modern F1 cars run.
With far reaching regulation changes coming onto the sport in 2014, the 2013 season is likely to be a year of consolidation, as few changes have been are written into this year’s rule book. So teams will be expected to optimise their designs from last year, correcting mistakes and adopting some of the better ideas of their rivals.
Some rules will have a small effect of car design and some trends from last year will be more common place. Unusually there have been few leaks or well-founded rumours circulating in the off season. This is probably as teams are expending a huge amount of resources in finding big gains for just one year’s competition, instead focussing on plans for 2014.
With the shift toward pull rod rear suspension, the teams’ mechanics are faced with a maintenance issue. As the pull rod reaches down into the gearbox casing, access to the transmission is hindered by the inboard suspension inside the gear casing. Most teams maintain their transmission by first having to remove parts of the inboard suspension. However the Ferrari engined teams have each found a neater solution to this problem. Sauber use the Ferrari gearbox and also follow a similar practice of using a separate module to mount the entire inboard suspension in between the engine and gearbox.
Car: Ferrari F2012
Having followed a very similar concept since the 2009 F60, Ferrari found in 2011 that the conservative route was not making up the ground to their rivals. The F150 was a fast car, but lacked that final ounce of pace to beat the Red Bulls and McLarens. This was exacerbated by the car being easy on its tyres, to the point where it had tyre warm up issues. This showed itself in qualifying were the car would not make the most of a tyre around a single lap and also in cooler weather, or where the harder Pirelli tyre was used. The team recruited Pat Fry in a major reshuffle of engineering staff. Fry spent the year assessing Ferrari problems and set about a recruitment programme of new staff and a more adventurous design programme. The resulting car is clearly very different from its predecessors.
Externally very little remains the same on the new car, it does perhaps shares Ferraris favour for a long wheelbase and clearly is set up to run a fairly steep rake angle. But only the front wing, which is derived from the late 2011 wing appears to be carried over. Even this detail was a development in preparation for 2012, Fry leading the team to follow Red Bulls format of front wing in both shape and aero elasticity.
With a similar wheelbase, the revised seating position is perhaps the only change to the cars layout. The seating position was altered for Fernando Alonso last year and has been altered once more for a lower position.
Of all the 2012 front ends Ferrari has one of the most striking, the nose being very wide and square in cross section. The width is part of philosophy to use the extended wing mounting pylons, as a pair of turning vanes cascaded with the normal undernose turning vanes. By making the nose as wide as possible within the space allowed within the regulations, more undernose surface can be used to accelerate air through the duct formed by the nose and vanes. As a result the edges are tightly radiussed and cannot be rounded as with other teams. The aesthetics of the nose being also worse for the rectangular cross section front bulkhead. Ferrari opting not to make a “V” shape of the bulkhead, in order to make the area under the raised chassis uncluttered to make the vane set up work most effectively.
The flow through this vane set up starts with the wing mounting pylons, these are wide spaced at their leading edges and they then converge to end inboard of the main turning vanes. The main turning vanes then pick up the flow accelerating between the pylons and sweep out to direct the flow towards the lower leading edge of the underfloor.
Curiously Ferrari has yet to fit a driver cooling vent into the nose. This hole is not mandatory and clearly not a requirement for a chilly Spanish pre season test.
As previously mentioned, the front wing is a derivative of the late 2011 wing. This was extensively detailed in a previous post. The wing is a three element set up, the main plane being slotted to create the leading two elements, and then the flap trails this. An extra slot in the down-turned corner of the flap helps keep flow attached in the steepest section of wing. The footplate is formed by the wing curving down on itself, while the upper section of endplate is a separate vane, albeit joined along a lot of its length to the foot plate. Front wings are now subject to a doubling of the deflection test used by the FIA 2011. So far the Ferrari wing has not exhibited the flutter seen last year, which is not to say it is not flexing.
A mention of front suspension in the cars launch analysis will be unique to Ferrari this year, as they have revisited an old direction with its layout. Every other car for well over ten years has had pushrod front suspension, but Ferrari has revived the pullrod set up for the front of the car.
This effectively turns the pushrod set up upside down, now the rod passes down from the upper wishbone and connects with the rocker, which is now mounted at the bottom of the chassis. According to Fry, this set up is a little lighter and has a slightly lower Centre of Gravity. These gains alone will not pay for the systems inclusion on the car, so the team claim to have found an aero benefit. The pullrod can be thinner, but the real gain is the pullrod is mounted near horizontal across the front suspension. This places it in line with the upwash from the front wing. Just as with the wishbones, its profile can be subtly altered within the rules to help control the wake from the wing and improve the airflow over the rear of the car. Despite appearances the pullrod is as effective in moving the rocker for a given wheel travel as a pushrod. The important factor is the angle between the rod and the wishbone is connected to, rather than the rods angle to the chassis. I’ll explain a lot more pull rod suspension in a subsequent article.
Although not a performance differentiator, the new roll hoop is very different concept to that seen in previous Ferraris. A far curvier pair of inlets are formed by the structure, this shaping being at odds with the ungainly nose. It is strange Ferrari have not undercut this area and exposed the structure supporting the roll hoop, which is the common practice to achieve more airflow to the rear wing. The main inlet feeds the engines airbox, while the smaller inlet piggy-backed behind it, most likely feeds the gearbox and hydraulic oil coolers mounted above the gearbox. The lifting point for the trackside cranes is formed by beneath the main inlet and enclosed by a simple bar connecting it to the top of the chassis.
It’s perhaps the sidepods that are the big performance area for the car this year.
Starting at their leading edge, the car sports a new format Side Impact Spar (SIPS) design inside the bodywork. Since 2009 Ferrari had a staggered SIPS arrangement, with a narrower spar sat ahead of a wider spar, creating the distinctive peaked sidepod inlet. Now it spears a single spar spans the sidepod and protrudes through to form the mount for the sidepod vane. This allows the spar to be wider, which creates an easier job to absorb the impact. Viewed from above the sidepod inlet lean inwards. This makes them more efficient at meeting the diverging flow that passes around chassis to enter the sidepod.
Much smaller and far more undercut, the sidepods now feature radiators mounted upright and splaying outwards from the rear of the car. Their new placement allows the flow through the cores to be directed outboard, rather than in towards the central tail funnel. This heated flow from the radiators passes out through the downswept chimney-fairings that differentiate the car from its rivals. This design keeps the centre of the car as slim as possible, with there being no tail funnel to obstruct the rear wing. Airflow passing through the undercut in the sidepod, still enters a coke bottle shape below the chimney-fairings and is passed over the diffuser. But these chimney-fairings also have a more important secondary use, for housing the exhaust outlets.
Additional cooling outlet area is provided in the tail of the sidepods, in between the rounded end of the chimney-fairings and the gearbox fairing. This gearbox fairing is nearly round in cross section also forms an outlet for hot air to exit from the engine bay.
With floor level exhausts no longer allowed, the teams have had to find different ways to make use of the powerful exhaust plume. Most teams have directed it over the sidepods towards the centre of the beam wing, but Ferrari have purposely placed the exits as far outboard as allowed (on the launch spec car at least). When viewed from above its clear these are aimed outboard of the rear wing endplate.
Sat inside the downswept chimney-fairings, the exhaust at first might be thought to be pointing downwards. But the rules state the exhaust outlets have to point upwards by at least ten degrees. Although not visible inside the chimney-fairings, the last 10cm of exhaust do indeed point upwards.
But the cleverly the down sweep of the chimney-fairings creates a downwash effect over the exhaust plume and this directs the combined flow downwards between the rear brake ducts and rear wing endplate. This set up will potentially reach the floor and act to seal the diffuser from the ground as with the 2011 EBD.
In testing the set up has gone through several iterations, firstly the exhausts exits were in line with the end of the chimney-fairings, but soon the exhaust tail pipes were shortened and the chimney-fairings above had to be cut back to maintain legality and also the allow the downwash flow to reach the shorter tailpipe.
At the Barcelona test the exhausts were again altered, this time being brought further inboard, approximately in line with the channel formed between the chimney-fairings and the engine cover. Now the exhausts appear to point inboard of the rear wing endplate. It’s not clear if this is an aerodynamic decision or a request for a less obviously aerodynamic solution from the FIA. Should the exhaust outlet stay in this position the sidepod and the chimney-fairings will need to be altered to optimise the downwashed airflow around the tail pipes.
Almost unspoken of amidst the talk of the front pullrod set up, Ferrari also switched their rear suspension on its head and gone for pullrod on the rear of the F2012. Last year we saw the Ferrari had a very complex setup around the rear suspension rockers and placing this hardware lower down around the clutch and engine drive shaft, will be a tough task package.
Mounted to the revised gearbox, the rear top wishbone has been repositioned this year. It appears to be nearly horizontal; this places it in line with the beam wing, so the wishbone can act as a flow conditioner ahead of the wing. Even if the new gearbox is not as low as the Williams, the wishbone needs to mount to a vertical extension above the gearbox. This wishbone mounting hard point also forms the mounting for the beam wing. At first this appears to be a duct, but is just the thick swan-neck mounting similar to that used by Marussia for the past two years.
Diffuserrear impact structure
Within the bodywork rules, there is not a lot of scope for a very different diffuser. So Ferrari have now added a full width flap around the diffuser on the new car.
Unusually Ferrari have not fully exposed the underside of the beam wing above the rear crash structure. Looking at the crash structure itself its clear it is shallow enough to allow this. Instead the crash structure has additional bodywork above and below it, which merges it with the beam wing.
As already mentioned the gearbox is a new design. The hybrid carbon and titanium case now has to mount a very different rear suspension system, with the switch to pull rod springdamper operation and the raised upper wishbone.
Last year Ferrari were notable for having a single selector drum for their seamless shift set up. Most teams use two selectors; each one operating alternate gears, so that the phasing from one gear engaging and the other disengaging can be adjusted. Ferrari with a single selector must be confident that their system can always shift with the same aggressive phasing, without the option to go for a longer overlap.
Ferrari develop their KERS with Marelli, the system retains the same layout as in 2011 with the MGU mounted to the front of the engine and the Batteries placed under the fuel tank. The power electronics reside in the right hand sidepod.
With the engine freeze, not much can be said of the engine. Ferrari have usefully provided a high resolution image of the 056 engine, complete with integral oil tank, but lacking the KERS MGU.
As the first real launch of a 2012 F1 car, McLaren have unveiled their MP4-27. In McLaren parlance this was the cars “technical launch” and was carried out at their Technical Centre in Woking, UK.
McLaren had one of the fastest cars in 2011, on its day the MP4-26 was faster than the Red Bull. So the basic approach of the new car did not need to veer too far from direction McLaren had been following. Last year the season was blighted by poor form in pre season testing. Most of the winter tests were interrupted by exhaust problems, as the now near mythical “octopus” exhaust broke after a few laps out on track. This exhaust turned out to be far simpler than the rumours suggested. The exhausts ran sideways across the floor to exit in a longitudinal slit ahead of the rear wheels. This being a complex way to achieve the same sort of fluid skirt that Red Bull achieved with their outer blowing exhaust layout. Once McLaren had followed Red Bulls lead with the exhaust, they were able to catch up. McLaren perhaps even surpassed Red Bull with the exhaust blown diffuser, as the Mercedes Hot Blown engine mappings were superior to the Renault cold blown solutions. Despite the rules trying cap the hot blown benefits as early the Canadian GP, the Silverstone GP weekend showed how much McLaren were lost relative to Red Bull when the restrictions really bit hard.
With a strong car at the end of 2011, the team have learnt about the damage a slow start to the year makes to their championship chances. This year evolution is required, McLaren do not need to find large chunks of time, but do need a car that will perform well at the opening races. Thus we see the refinement of old concepts and little in the way of radical development.
Thus the new car bred from the recent line of McLarens, the family resemblance goes further than the colour scheme. With a low nose and sweeping lines over rounded sidepods are now trademarks of the Woking design team. With the second year of the fixed weight distribution and Pirelli tyres, little needed to be done to the cars basic layout. Running much the same chassis, fuel tank size and gearbox, so the wheelbase is similar to the previous car.
Although the 2012 Pirelli front tyres are a new shape tyre, Paul Hembury from the tyre supplier confirmed to me that the change in the new profile is “not visible to the eye”. So only small optimisations of the front end aero are needed to cope with the change.
The studio photos of the car in side profile show off the amount of rake the car is designed to run. This is also a carry over from 2011, as the car could often be seen with a clear 10cm of ride height at the rear axle line. Although managing rake will be harder this year as the greater rear height introduces more leakage into the diffuser from the sides. As yet the teams solution to seal the diffuser are hidden by a simple floor fitted to the launch, although these are removable panels and more complex designs will soon be seen.
With so much to carry over in philosophy and design, what has changed for 2012?
MP4-27 in detail
The stand out points on the MP4-27 are the nose, sidepods and exhaust position.
Firstly the front wing is near identical to the late 2011 wing, so we can expect its general design to carry over, as will the snow plough vane below the nosecone. But the height of the nose at first appears to be at odds with the 2012 rules on a maximum 55cm height for the front of the nose.
Looking closer at McLarens chassis in side profile its clear the family history of low noses has helped here. The dashboard bulkhead is may be just 3cm higher than the cockpit padding (which is 55cm high), the chassis top then curves downwards towards the front wheels. By the point of the front (A-A) bulkhead the top is lower than 55cm, may be as low as 5cm below the maximum height. When compared to the maximum heights (the dotted line on the drawing), its clear this is a very low nose overall.
This creates less space under the raised nose, but the teams snow plough device under the nose works aggressively as a turning vane, so perhaps the team don’t need the higher chassis to get the correct airflow to the sidepods leading edge. McLaren also find the lower nose provides the classic vehicle dynamics benefits of a low CofG and a less extreme front suspension geometry. This trade off works for McLaren and goes to prove not everything in F1 has to be a compromise in search of aero advantage.
Although details around the front end will change, the wheels are typically a design chosen to last for the whole season. This year the McLaren Enkei wheels sport a novel set of drillings to aid brake cooling. The usual spokes formed into the wheel between the hub and the rim, stop short and a radial set of holes are made near the rim. Although not present of the launch car, there will be a dish shaped fairing added to small pegs formed into the wheel to aid the airflow out of the wheel.
In 2011 McLaren were not afraid to try a radical sidepod set up, This was the “U” shaped sidepod, with the angled inlet shape creating channel in the upper section of sidepod (About the MP4-26 “U” shaped sidepods). This year the team have adopted more typical sidepod format, with highwide sidepod inlets and steep undercut beneath. I got to ask Tim Goss about this:
ScarbsF1: Can you tell us about why the concept’s changed, why you don’t feel that was a benefit this year?
Tim Goss: Last year’s U-shaped side-pod worked very well with what we were trying to achieve last year with the exhaust layout, it was all intended at creating more down wash to the rear end, and it performed particularly well last year. This year at a fairly early stage we set about a different approach to both the external and the internal aerodynamics of the car, and then once the exhaust regulations started to become a little bit clearer then it was quite obvious to us that the U-shaped side-pod no longer fitted in with both the internal aerodynamics and some of the external aerodynamics that we pursued early on. So it works, it worked very well last year, but it’s actually just not suited to what we’re trying to achieve this year.”
In frontal profile the high and wide cooling inlet is obvious. The team have been able to incline the sidepod tops slightly, this isnt quite a “U”pod shape, but is quite distinctive. At the rear the team have kept the sidepods narrow and slimmed the coke bottle shape in tightly to make the sidepod join the gearbox fairing creating a continuous line of bodywork to the very tail of the car.
As well as the external airflow considerations, McLaren looked the sidepods internal airflow, they wanted a cooling exit on the cars centreline. This would have been compromised with the “U” sidepod, so the more conventional shape was selected. The cooling arrangement is similar to Red Bulls philosophy, the radiators direct their heated airflow upwards and around the engine, this then exits in a tail funnel. The launch car had quite a modest central outlet, but we can expect to see far larger versions used at hot races.
Aiding the tail funnel there are also cooling panels on the upper leading edge of the sidepod, either side of the cockpit padding and various panels arund the rear of the coke bottle shape. Different panels will be used depending the cooling andor drag demands of the of the track.
Other cooling functions are covered by the inlet below the roll hoop. Last years double inlet set up has gone and now a single duct is used. This probably cools both the gearbox and KERS.
The other notable aspect of the sidepods are the exhaust bulges. These stick out prominently on the flank of each sidepod. They don’t serve an aerodynamic function themselves, but simply fair-in the final 10cm of exhaust pipe. This final section of exhaust is now strictly controlled by the regulations. Its position must sit within specific area, it must point upwards between 10 – 30 degrees and can point sideways plus or minus ten degrees. McLaren have fixed the exhaust in the lowest most rearwards position possible, the tail pipe then pointing steeply upwards and inwards. From the limited view it would appear to direct the exhaust plume towards the outer span of the rear wing.
This would make a blown rear wing (BRW), the added flow from the exhaust aiding the wing in creating downforce at lower speeds. The exhaust position and fairing also suggests an alternative exhaust tailpipe could be used. Paddy Lowe confirmed that different solutions would be tried in testing. From overhead its clear to see the exhaust could be angled differently to blow over the rear brake ducts fairings to create downforce directly at the wheel.
The gearbox case design is not the shrunken design we saw with Williams in 2011 , the differential is low but not unduly so. The top of the case sitting neatly under the tail funnel. Pull rod suspension remains at the rear of the car, while conventional pushrod is on the front end. Lowe commented that the Lotus brake antidive system was not specifically looked at, but was part ”of a family of solutions” that has been looked at in the past. The engineers feeling that the Lotus system was illegal and hence had not been explored further. They declined to comment of the possibility of an interlinked suspension system.
Behind the gearcase, the rear impact structure is mounted midway between the beam wing and floor, fully exposing both the beam wing and allowing airflow into the central boat tail shape of the diffuser. As the diffuser was covered up, its not clear if there are features to drive airflow into the starter motor hole. A new feature on the beam wing is an upswept centre section, the extra angle of attack in the middle 15cm of the wing having a slot to help keep the airflow attached. The upper rear wing is a new design albeit similar the short chord DRS flap wing, we saw introduced at Suzuka last year. The DRS pod is still mounted atop the rear main plane and its hydraulics fed to it through the rear wing endplates. The flaps junction with the endplates follows recent McLaren practice with a complex set of vents aimed at reducing drag inducing wing tip vortices.
Not much else in terms of structures or mechanical parts were evident at the launch. Lowe did confirm to me that the Mercedes AMG KERS remained packaged under the fuel tank in one assembly. Also adding that there would not be an significant weight loss to the system. As a significant reduction in weight was made between the 2009 and 2011 season, via the consolidation of the Batteries and Power Electronics into one unit.
Mp3 of the MP4-27 Engine fire up via McLaren
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.
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.
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.
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.
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.
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.
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.
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.
These and probably other solutions will be seen in 2012 to maintain the ideal ride height under all conditions.
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 threefour 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.
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.
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).
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.
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 lowtapered, 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Lotus Renault GP (LRGP) have been on one of the teams most innovative with their suspension over the past decade. As RenaultF1 They introduced the Tuned Mass Damper (TMD) back in 2006 and have since raced conventional Inerters. Inerters are a special component in the suspension to counteract spring effect of the TyresSuspension, using a spinning mass on a threaded rod to control these loads.
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”.
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).
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!
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 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.
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.
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.
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.
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.
More references on Inerters
An excellent Sutton Images picture seen on F1Talks.pl, taken through the aperture on the front of the McLaren has given us a rare chance to see the set up of the front suspension.
Typically most teams follow the same set up for the front suspension in terms of the placement of the rockers, torsion bars, dampers anti roll bars and heave elements. As unlike with rear suspension, the raised front end almost dictates a pushrod set up in order to the get the correct installation angle of the pushrod. However the McLaren antiroll bar shows there is some variation in comparison to the norm and also highlights Ferraris similar thinking in this area.
In comparison to my more recent posts, this is not a breakthrough in design, simply a chance to see the teams playing with packaging to achieve similar aims.
As an overview of the conventional of the rocker assembly in the attached diagram shows the rockers are operated by the pushrod, a lever formed by the rocker operates each of the suspension elements. Compressing the heave spring and wheel dampers, extending the inerter and twisting the torsion bars.
Typically teams use a “U” shape anti roll bar (ARB). In this set up the antiroll bar is connected to the rocker via drop links, and then each arm twists the torsion bar when the car is in roll. When the car is in heave (car going up and down, no roll) the ARB simply rotates in its mounts and adds no stiffness to the suspension. Different torsion bars in the anti roll bar create different roll stiffness rates for the suspension. Teams will either switch the entire ARB assembly for a different rate ARB. Red Bull have engineered their ARB for the torsion bar to be removed transversely through the side of the monocoque, in a similar fashion to removing the normal torsion bars.
However McLaren and Ferrari have gone a slightly different route.
In McLarens case their ARB is a simple blade type arrangement. These blades are splined to each rocker the blades are joined at their ends by bearings and a drop link.
When in roll the rockers rotate in the same direction, one blade goes down and the other goes up, the stiff drop link transfers these opposing forces and the blades flex. These opposing forces add stiffness to the front suspension in roll.
In heave the rockers rotate in different directions, both blades move down and the increasing gap between their ends is taken up by the drop link. So the blades do not flex and do not contribute to heave stiffness.
Different thickness blades create different roll stiffness; they must be removed from the rockers and replaced to achieve this.
Ferrari have used this solution at least since the late nineties, the idea has been seen on older Minardis too. I suspect the idea was taken to Minardi by Gustav Brunner, who may also be the creator of this elegant solution.
Similar to McLaren the roll stiffness is provided by blades splined to the rockers. But the connecting mechanism is instead a single bearing sliding inside an arched guide. Just as with McLaren ARB, when in roll the two ends push against each other to create the reaction force to prevent roll. When in heave the bearing slides through the arc of the guide and no force is passed into the suspension.
I don’t believe either of these solutions has a compliance benefit over the other. The McLarenFerrari systems may be take up a little less space inside the nose and may weigh a little less. But both will be a little more complex when changing the roll stiffness.
As we get towards the end of the season we often see teams start to get relaxed with the usual secrecy in the pitlane. This weekend in Korea was no different with several technical details being bared to the cameras for the first time.
In particular was the first picture I’ve seen of the Mercedes rear suspension, http://www.f1talks.pl/?p=11598&pid=6274 (Credit to F1Talks.pl and SuttonImages.com for the picture)
The surprise is that Mercedes appear to have adopted a hydraulic solution for managing rear roll andor heave stiffness. Nothing is new in F1, this solution closely matches the aims of the 1995 Tyrrell Hydrolink system, which I hope to cover in detail in a future blog post. Indeed this is not even new in current F1, as several other teams already run similar and perhaps even more developed systems. But this is the first evidence I’ve had of teams interconnecting the suspension with hydraulics.
I spoke to renowned race car designer and suspension expert Andy Thorby about the use of just such a system, “I think most or all the teams are using linked hydraulic actuators on the corners.” adding “they allow you to tune the attitude change of the car under aero load, independently of corner spring rates” by altering both heave and roll stiffness.
Mercedes were one of the many teams to switch to pull rod suspension for 2011, to gain the aero benefits and a lower CofG. With space at a premium at the back of an F1 car, compromises in packaging the various suspension elements need to be made. At its launch it was clear the Mercedes pull rod arrangement placed the rocker quite rearward, in comparison to other pull rod arrangements which place the rocker towards the front of the gear case. The conventional forward rocker placement, puts the heave spring and antiroll in the space at the front of the gear case, packaged around the clutch.
In Mercedes case the rocker is packaged the other side of the gear cluster, just under the gearboxes cross shaft. This leaves little room for the antiroll bar and heave spring. It does however place the rocker and torsion bars very low for the benefit of packaging, aero and CofG. Albeit these are small benefits, perhaps Mercedes choice of a short wheel base did not leave space for the suspension to be packaged around the clutch, as the gearbox length is a critical factor in wheelbase length.
So left with the lack of space to place either a mechanical heave element or a antiroll bar, it appears that Mercedes have opted to create a passive hydraulic system. This is not to be confused with any form of active suspension or the cars high pressure hydraulic systems, this system will be entirely self contained to remain within the rules on suspension design. As the system reacts only to suspension loads, it is clearly legal and there is no question of interpretation in its acceptance by the FIA.
What Mercedes have in place of a conventional anti roll bar and heave spring are hydraulics units (yellow), which probably also act as the dampers. These are connected via fluid lines (blue) to the central valve block and reservoir (red). Springing for the rear wheels is managed by the torsion bars. One end of which is conventionally located within the rocker pivot, the torsion bar then leading forward and connecting to the front of the gear case.
There is still some hardware at the top of the gearbox, which looks like it might be the mounting for an anti roll bar (ARB). But in this set up, its hard to see how the suspension rocker will act on the ARB. So Its not clear if the car started the season with a mechanical system, or whether it was designed purely with this solution in mind.
The teams early season struggle with rear tyre wear, may or may not be attributable to this system. My feeling is that other rear suspension and car layout factors have influenced the tyre problem, to a greater degree than this hydraulic solution. Although in a car that had a difficult pre-season and fundamental design problems. Getting the hydraulic suspension to work as well, may have been just another drain on resources for a team trying to recover its pace.
How it works
A cars individual wheel dampers displace hydraulic fluid as the suspension moves, creating higher pressure in one end of the damper and lower pressure in the other. To act as a damper, valves in the damper control the rate in which the fluid moves between the two chambers to create the damping effect.
In the passive hydraulic unit, the fluid is displaced not from one chamber to another, but via pipes through a valve block and into the opposite hydraulic unit. How the upper and lower chambers are interconnected left to right make the system react differently to inputs from the suspension. These being a resistance to roll or heave.
In a simplified view we can see the system working in two modes, with the fluid lines in ‘Parallel‘, where one units upper chamber connected to the opposite units upper chamber. Or, in ‘Crossover‘, where the upper chamber in one unit is connected to the lower chamber in the opposite unit.
In each mode we can see the effect of the car in roll (tilting from cornering loads) or heave (going down from aero or braking loads).
When the car is in heave, both upper chambers create high pressure. This creates resistance between the two systems wanting to displace their fluid. This has the effect of increasing the cars heave stiffness.
When the car is rolling, the upper chamber on one side and the lower chamber on the other side create high pressure. As these chambers are now connected to the lower pressure chambers on their opposite side, the fluid displaced with little resistance. This presents no increase in the cars roll stiffness.
When the car is in heave, both upper chambers create high pressure. As these chambers are now cross connected to the lower pressure chambers on their opposite side, the fluid is displaced with little resistance. This presents no increase in the cars heave stiffness.
When the car is rolling, the upper chamber on one side and the lower chamber on the other side create high pressure. As these chambers are cross connected to the high pressure chambers on their opposite side. This creates resistance between the two systems wanting to displace their fluid. This has the effect of increasing in the cars roll stiffness.
If a team simply want a hydraulic system to create one suspension effect, then they can rig up a basic system based on one of these patterns. However, with a valve system connecting in the centre of the pipes, then a single pair of hydraulic units and would be able to control both heave and roll stiffness. Such a system would not need external pressurisation or any control software to operate the valve block.
However these systems are still present handicaps to development. Friction in the valve seals and the valve block, will create heat and variances in the systems response. This heat will be an enemy of the system, as it effect on the volume of fluid in the system, thus the stiffness the system provides to the suspension will alter. As a result the system will need to be a ‘constant volume’ system. Where the volume of fluid is managed depending on its rate of thermal expansion. This is probably part of the function of the small reservoir mounted to the valve block.
Equally important is the ‘installation stiffness’ of the system, that is the flexibility of any components, especially the flexible fluid lines, as this will alter the systems response.
But these and other issues related to hydraulic systems is already well understood by the teams with similar hydraulics being used both for the braking system and the high pressure electro-hydraulic control systems.
One area which presents trouble to the teams is the modelling of these systems. The design and simulation of the hydraulic element is not necessarily covered by conventional suspension and ride simulation software. I asked , Peter Harman, Technical Director of Deltatheta Ltd (http://www.deltatheta.com) about these issues. “I have advised teams on how best to simulate them“ adding “it sounds like it is a common development“. The problem is the hydraulic elements don’t fit in with conventional suspension design software. As Peter explains “Traditionally car companies have used MSC Adams for suspension modelling, and this has been adopted for ride simulation by most F1 teams, however Adams is really just a mechanical tool and doesn’t do hydraulics well“. Thus teams need to alter their approach, needing specialist add-ons and code to augment the already well established suspension development solutions.
Of course the systems will also be physically rig tested in back to back comparisons with their mechanical counterparts on the teams multi-post rigs.
Overcoming these issues with good approach to the detail design work, a hydraulic system should be able to get very close to the response of a Mechanical system. However the potential of the Hydraulic solution does offer some other benefits over purely mechanical systems.
Once you have the ability to independently tailor the damping and stiffness of the heave and roll functions. The next obvious step is to control the pitch of the car. Pitch is when the car brakes or accelerates, one end of the car moves down and the other moves up. Braking creates a forward pitch, with reduced front ride height and greater rear ride height. Acceleration is the opposite situation.
As we’ve seen for the past few years controlling pitch is critical to maintaining a low front wing ride height, with out sacrificing splitter wear or excessive rear ride height (thus rear downforce).
Linking the hydraulic unitsvalve blocks between both front and rear axles, will allow the same resistance to pitch, as it does to heave on just one axle. This will increase the front heave stiffness, reducing forward pitch and preventing the splitter grounding excessively. This effect under braking could be further augmented with either gravitationally load sensitive valves, altering the displacement of fluid front to rear. Or similarly, a valve directly controlled by brake pressure. The former G-load system already in legal use on the individual wheel dampers and the latter solution a common fitment to motorbikes in the eighties, often termed Anti-Dive.
With Rake being ever important to the cars aero set up, such linked systems are increasingly being investigated by the teams. Indeed one team has run such a solution since mid 2009 and at least two other teams (one at each end of the grid) ran them last year.