It’s been discovered the FIA have issued a Technical Directive in response to a team’s request for clarification on potential exhaust aero interaction with the 2016 exhaust tailpipe rules.
In September last year, the FIA confirmed the change in the exhaust tailpipe regulations that separates the pipework for the wastegate\s from the turbo. This move was made in order to add to the sound, previously muted by having both devices blowing through the same tailpipe. To prevent any obvious aero trickery with blown effects from the extra tailpipe\s, the rules fix the pipe’s exit in the same area as the current tailpipe. However, opening up the exhaust outlets could still bring some potential exhaust interaction with the aero, along the lines of the F-Duct or Drag Reduction Duct. This new FIA TD bans any interaction between the exhausts and fluidic switches.
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.
For three races now, Lotus have had a prototype ‘drag reduction device’ fitted to the cars rear wing. This is a system of ducts and is not linked to the normal DRS that moves the rear wing flap. Mysteriously described by Lotus as the ‘prototype device’, most people in the paddock are still calling it DDRS (Double DRS), as although its not part of the DRS, its aim is to reduce drag on the straight for more top speed.
The Lotus device can be recognized by the cars sporting two roll hoop inlets and ductwork exiting the engine cover between the upper and lower rear wings. This was first tested In Friday free practice in Hungary and again in Germany, albeit only on Raikkonen’s car. For the Belgium GP, the system has been applied to both cars, but the wet Friday practice session means the team have elected not to run the device for Qualifying or the Race.
The device came about from the Lotus request for clarification on Mercedes DDRS, which is linked to the rear wings DRS to stall the front wing. This system was controversial as switchable drag reduction systems were effectively banned after the F-Ducts of 2010. However the rules to counter this were largely worded to reduce the stalling slots in the rear wing and the driver interaction in turning the system on or off. The Mercedes system sidestepped these rules by having the stalling slot in the front wing and the system switch by the DRS opening (an allowable moveable aero device). When in Bahrain the FIA gave clearance for other drag reduction systems, whether linked to DRS or not, Lotus announced they would take advantage of the clarification and develop their own device.
Unlike Mercedes whose system stalls the front wing to balance the aero when the DRS rear wing is used in qualifying (and the race); The Lotus system is passive and not linked to an external switch. Instead the system uses increasing airspeed to send more flow to slots under the wing to stall the airflow and reduce drag (and downforce). Having the passive system means that the Lotus device can be used to stall the wing above a certain speed on every lap, meaning the small c5-8kmh speed advantage is available on every straight and fast corner. With the system being tuned to airspeed, the wing can be designed to stall at speeds high enough to allow fast corners to be taken with the rear wing stalled. At these speeds the diffuser provides enough downforce for cornering and the rear wing in not required for aero load. Typically teams will want this stalling to occur at speeds of over 250kmh.
The system is formed of two roll hoop inlets feeding a fluid switch, and then two ducts tee off, one to exit nuetrally and one “L” shape duct to blow the rear wing. The inlets are clearly visible either side of, and slightly behind the roll hoop inlet, they are reminiscent of the 2010 F-Duct, although they are permanently bonded to the roll hoop structure, so even when the car is running without the device, they are still in place. These inlets form ducts that pass up and over the airbox snorkel to merge into a single duct that then passes down to the fluid switch above airbox. Indeed the pictures from Spa show that part of this duct is bonded to the airbox before a tail section of duct is bolted to it. This is where the other conenctions to the fluid switch is hidden; as we can see the fluid switch splits into two exit above the airbox, with one exit above the other. The outlets are formed by machined metal flanges, to ensure that the connection to the subsequent duct work is air tight.
The neutral duct exits over the centre of the beam wing, a small Y75 winglet (monkey seat) is formed around the exit to reduce pressure at its trailing edge. Visible inside the exit of this duct is a smaller duct exiting within, so the apparently large cross section central duct may be a double walled structure housing two exit ducts.
With the neutral duct’s outlet blowing over a revised beam wing, it’s possible that the effect of the Device when not stalling the rear wing is to aid the upwashed airflow coming up under the centre of the car, to create downforce. Albeit this would be an inefficient way to create downforce, it is probably a way for the system to contribute to laptime when the upper rear wing is not stalled.
Teed off from the from the fluid switch duct is the “L” duct, this is far smaller in cross section than the central duct, and would offer a lot of resistance to airflow, most likely to encourage airflow at lower speeds to pass into the neutral ducts exit, rather than up to the rear wing
The “L” shaped duct has the 90 degree bend, not for aero reasons, but as a workaround to the zone ahead of the rear wing not being allowed to have bodywork. This was part of the 2010 F-Duct ban on bodywork (shark fins and F-Ducts) reaching the rear wing.
Other than the join of the “L” duct to the underside of rear wing’s main plane, the top rear wing and endplates appear to be the same as the non-device set up. The “L” duct meets the wing, but does not blow into it. Unlike the 2010 F-Ducts the stalling slot is not a lateral slot across the wings span, but instead four small vertical slots in the “L” duct, these blow sideways where the “L” duct meets the wings underside. Being part of the “L” duct and in the middle 15cm of wing, they are exempt from the minimum radius rule that was introduced to ban F-Ducts.
It’s clear the system has had to be compromised to fit into the post F-Duct rules, but in every sense is meets the regulations and would be hard to declare illegal without a new clarification of the rules being issued by the FIA.
How does it work?
There are two aero effects being used with this device, the method to ‘switch’ the blown effect on above certain speeds and the effect to stall the rear wing.
The ‘Switch’ effect, as previously described is passive, with no moving parts or external interaction. There is clearly something clever going on with the ductwork inside roll hoop inlets to the fluid switch. Its not clear if this fluid switch is somehow linked to the engines airbox and the pressures created within. But I increasingly suspect hat engine airbox pressure provides the “switch effect” to the fluid switch. Perhaps at higher speeds and with full throttle the pressure difference inside the airbox sets off the fluid switch to alter the flow from the neutral to the “L” duct. Technically this is legal, but other teams might take a different view off this if indeed that is the case.
As speed or airbox pressure increases the flow passes into the fluid switch, to change the flow from neutral to stalling. Without seeing the remaining ductwork, this is purely speculation, but the system appears to more complex than simply increasing air pressure in the duct eventually leading to stalling at higher speed.
Then the stalling effect is created by the two pairs of slots in the last section of “L” duct, these are blowing sideways across the wing, the effect sets up a delta shaped pair of vortices that turn the laminar airflow passing under the wing into turbulent flow. This would stall a large section of the wings airflow, reducing downforce and with it the drag induced by the highly loaded wing. We can see evidence of this effect from Hungary when one of the practice runs used flowviz paint the distinctive “V” shaped area of stalled flow emanating from the slots could clearly be seen (these pcitures are posted on the F1Technical.net forum). The stalled flow only appears to cover about half of the wings underside, the limitation of the vertical slots rather than a wider slot as used in 2010 being the restriction.
We’ve seen Mercedes trial a similar device on their car at Spa, with other teams rumoured to have a system ready to test subject to conditions in Spa and its benefit at Monza. The gain of the system is small, but anything that improves aero efficiency will be useful, whether to allow a higher top speed for a given downforce level, or vice versa, a gain in downforce level for a given top speed. The gain is likely to worth no more than a tenth per lap and limited in use for circuits will shorter straights and lacking fast corners.
One issue facing the FIA and other teams is that the Mercedes DDRS solution will be banned in 2013, via wording to prevent secondary use of the DRS opening. But being passive, the Lotus system does not employ this solution to stall the wing. As it stand the Lotus will be legal for 2013, but the FIA are likely to find some wording to also outlaw this method of drag reduction.
Something often said of banned developments in F1, is that once understood no solution can be unlearnt. So while the FIA fights to ban technologies that they feel aren’t suited to F1, the teams will always try to apply that solution in a different way.
McLaren understood how to stall a wing by blowing a slot perpendicular the wings surface. This knowledge lead to the F-duct in 2010, as you will recall the FIA moved to ban slots in the rear wing and direct driver interaction with the cars aero. But the knowledge of blown slots to stall wings has remained and it’s been Mercedes who have been busy trying to apply it in other ways. This culminated with the tests of an F-Duct front wing late last year. Rumours continue to fly about the teams use of the F-Duct front wing (FDFW) in 2012. I understand the 2012 Mercedes AMG W03 does have an F-Duct front wing and this is operated by the rear wings DRS. Based on information I have from the sources around the team, and from looking at the cars performance and construction mean I can speculate how and why Mercedes might be using the FDFW.
As detailed in two articles last year, Mercedes are believed to have run blown slots under the front wing to stall the wing at higher speeds. Three reasons came up as to why this would be used; reducing drag, managing wing ride height and managing the cars aero balance. With nothing official being said by Mercedes, we were left unsure as to exactly why a passive FDFW would benefit the car.
Some observations from the Mercedes team last year might aid us in putting a picture together of how the 2012 solution might benefit. Mercedes were the first team to really exploit more of the open DRS effect and use a short chord flap. The open DRS boosted Mercedes top speed and could be used through the lap in qualifying. Despite this benefit the teams did struggle in qualifying, their race performances latterly became better than qualifying suggested. It was clear for Michael Schumacher at Least, that the cars handling wasn’t ideal and the team sought to resolve the cars nervousness.
Bearing these points in mind, the potential benefits of a FDFW become more apparent. Mercedes need more qualifying pace; they can exploit their DRS more frequently during qualifying, but in higher speed turns the cars lacks the balance for the drivers to fully commit through the turn.
If they can cure these issues, then they will further up in qualifying and able to take the fight to the leading teams. I now believe the FDFW works to manage the cars balance in high speed turns when the DRS is activated. As DRS reduces both rear drag and downforce, the car becomes unbalanced in downforce front-to-rear. In other words pointy or oversteering. Which in high speed turns in qualifying is hard to handle. At higher speeds even with DRS reducing rear wing downforce, the car has enough downforce to make it around corner, the problem is how to make the car more balanced front-to-rear when DRS is activated.
The FDFW we saw last year appeared to be passive, this uses nothing other than airspeed to trigger the slot to blow enough to stall the front wing. If matched to the speed DRS would be used at (in qualifying), the passive FDFW would help balance the car, by reducing front downforce to match that of the rear. However the front wing would always stall at these speeds, whether DRS was in use or not, so outside of qualifying the wing would stall and the car would understeer. With Parc Fermé rules in force, the team cannot change the FDFW between qualifying and the race.
Another issue with the passive FDFW, is that under braking as air speed reduced, the wing would need time to start working again. But this early phase of braking is just when the driver needs the most downforce. What the FDFW ideally needs is a method to link its activation to that of DRS, in other words an active F-duct.
As we’ve already mentioned, driver activation is not allowed, as are any other moving parts to directly alter the airflow. This brings up the Designers favourite interpretation in the rule book, primary and secondary purpose. Any part on the car can be for a primary purpose; sometimes any secondary purpose is banned or restricted. However in most cases the rules are vague and Designers are free to find secondary uses for a solution on the car. Examples of this are the cooling fans on the Brabham Fan car, the engine blowing off throttle for blown diffusers or brake torque altering ride height on the Lotus Reactive Ride Height system. In each case the first element was legal as its primary purpose was as stated, but a secondary purpose was able to be exploited.
The DRS rules are quite clear that the flap must not be shaped to allow other aerodynamic benefits. In fact this wording affects only a portion of the flap and additionally the endplate is excluded from this wording. If the team could find a way to blow into the front wing a duct when DRS is activated, then the FDFW could work synchronously with the DRS.
I believe Mercedes have found a way, by creating a duct through the endplate. When DRS is closed, the flap and the plate it attaches to is in a nearly vertical position. When DRS opens, the area the flap initially covered is exposed. If this area featured an opening that lead into a duct inside the endplate, when DRS opened the high pressure above the wing would force flow through the duct. With this duct then routed through the car to the front wing, when DRS is open the FDFW would be blown and stall in unison with the rear wing. Clearly when DRS closes the duct would be closed off and the duct would stop blowing the FDFW, restoring front and rear downforce.
Some evidence around the rear wing of the W03 shows this could be possible. We have to be careful to pinpoint every feature on the rear wing as being FDFW related as the DRS mechanism is hidden inside the endplate as well. Some access panels on the wing could be for DRS, FDFW or other purposes, some might be for both. In my research I’ve yet to see a clear high resolution shot of the Mercedes with DRS open, this is unusual as most other teams have been seen with the DRS in effect. Equally clear pictures of the inside of the endplate, where the flap meets the endplate, are in short supply. With this lack of material I can propose a solution, although the actual parts may diffuser is location and appearance. Its expected at this weekend Australian GP the rear wing duct will be exposed as the car uses DRS on the straights. We will need photographers with a big lens and steady hand to catch sharp pictures of the inside face of the endplate, when DRS is activated.
Evidence of the duct can be seen on the car, when the car is not moving. Clearly the W03 rear wing endplate is quite thick, an access panel that houses the DRS actuator is outboard of the flapendplate intersection, plus there is another panel in line with the beams wings intersection with the endplate. I’d suggest the duct is opened by the flap and hinge plate, the duct then routes through the double skinned endplate down into the beam wing. This then exits through the duct that mounts the beam wing to the gearbox. There’s a tortuous route for the duct through the car to reach the front wing, but this isn’t that dissimilar to the 2010 F-Duct routing. As with McLaren in 2010, the trick is to design the duct into the car at an early stage to minimise losses through the ductwork. This usefully makes it harder, but not impossible to copy. To copy this set up the monocoque needs to be altered and the nose cone needs the apertures into the front wing mounting pylons to feed the airflow into the front wing itself. This requires time to redesign and potentially re-crash test any changes.
But, can this set up be legal? The act of stalling a front wing through a blown slot is legal, although F-ducts are banned, it’s only via the slot in the rear wing that this was achieved. Direct driver intervention is banned, but the driver is allowed to operate the DRS, so any secondary aerodynamic effect of that is not prohibited in the rules.
Although the rules allow this, it’s possible the FIA could issue a Technical Directive on the matter, that any overt secondary effect of using DRS is not allowed and the whole solution could be banned in a stroke.
With a tight and competitive season in prospect qualifying performance will be critical. Notwithstanding the potential structural work to allow the duct to pass through the car, the DRS activated F-duct Front wing is an attractive option for the other leading teams.
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.
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.
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.
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.
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.
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.
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 innerrear 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/
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.
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.plSutton 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 partclosed throttle.
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 BlownCold 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.