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Showing posts with label Exhausts. Show all posts
Showing posts with label Exhausts. Show all posts
9 Mar 2013
Rake - Does it mean additional downforce?


This isn't a public service announcement regarding your common garden 'Rake' but a feature on the nose down phenomenon used in F1 referred to as 'Rake' (The term however more than likely owes it's heritage to the garden rake as pictured above).



Creating downforce in F1 as we know is complex endeavor and requires one to think of the car as a whole rather than the sum of it's parts as by altering or achieving one effect can have a positive or detrimental effect elsewhere on the car. The word 'Rake' refers to the nose down pitch angle of the car and is most commonly referred to by the media as a sign of a team running with high rear end downforce.

The last time we saw 'Rake' used extremely was in 2011 when teams utilised Off Throttle Blown Diffusers (OT EBD). There are several reasons for this but the easiest way to explain it is that those cars had more rear downforce by virtue of the exhaust plume assisting in Diffuser extraction. This was achieved by releasing the exhaust plume directly into the gap between the rear tyre and floor of the car, nullifying the effects that the rear tyres have on the airflow in that region (Tyre Squirt) impinging on the Diffuser itself and is what the media refer to as 'Sealing' the diffuser. The exhaust plume creates an airdam or skirt whilst also helping to extract the vortex that trails off the edge of the Diffuser thus creating more downforce. (This is also the reason it's more difficult for a car to follow behind a car using OT EBD as the upward wake induced by the vortex is much larger)

Above: As a means of showing the appoximated path of the exhaust plume wanted by the teams I've highlighted it in red on the MP4/28. Obviously the Brake Duct and Suspension obscure the gap between the floor and the diffuser but hopefully this goes some way to explaining what the teams are looking to achieve.

So as I mentioned let's not try to think of 'Rake' in isolation and think of the other effects it has on the car. At the front of the car the nose down attitude created when raking the car drops the Front Wing into ground effect, as the wing gets closer to the ground the air accelerates increasing the downforce generated, whilst a vortex is generated at the joint between the wing and Endplate. This effect increases until such a point that the wing is so low that the ground and wings boundary layers combine reducing downforce and bursting the joint vortex. Obviously the rotating wheel behind the Front Wing has an impact of this effect and is the reason we see most teams turn out the Endplates to encourage the flow around the wheel. Meanwhile the Front Wing Cascades intercept some of the airflow above the wing flaps and by and injecting the airflow above the wing help to manage the airflow around the wheel.

Moving to the central section of the Front Wing and it's onward effect with Rake and the combined effect of the Splitter during this ruleset: The Y250 section is the central section of the Front Wing's mainplane that is mandated in dimension to 500mm in width. It's design/construction is also mandated and so the teams have to find ways in which to control it's aerodynamic effects as although it is designed to be neutral of course in terms of aerodynamics nothing is. The only difference here is all the teams have to manage the same aero problem, a vortice is shed from either end of the section as the section changes profile. This vortice encloses the central portion of airflow between the pylons making moving airflow either side of it more difficult, it does however mean that air spilling from the tyres when cornering has a more difficult time impinging on the centralised flow. Although teams don't have the freedom to modify that section of the car, many have however taken the opportunity to place the FOM camera's behind the section which undoubtedly changes the characteristics in the central portion of the wing. (The FOM camera's are also regulated in size and shape, so no one team can glean an aerodynamic advantage from their placement) Red Bull's movement of the FOM camera's to the hammerhead position on the nose further suggests the team have gone to in order to tilt the Front Wing backward under aerodynamic load with the camera's being placed behind the Y250 section it could have had an undesired effect on the aero aft of it.

Running with more Rake can become a problem for teams in qualifying and towards the end of the race as this is when the car is at it's lightest. The biggest issue comes under braking as the car pitches forward and can cause the Front Wing to either collide with the ground or Stall as it's range becomes too low to work aerodynamically. However moreover the problem comes from the Splitter as it is more likely to hit the track than the Front Wing and as we have already discussed, too much of this and it will wear the Skid Block resulting in a disqualification.

Above: I have highlighted the Y250 region in red on the underside of this great image captured of the underside of the Lotus E21.  The blue arrow point to the element I'm describing as the Splitter whilst the yellow arrow shows the fence on the side of the Splitter that is used to direct the Y250's vortices

The section of the car that really regulates the amount of rake that a team can run is the T-Tray/Bib/Splitter or whatever other name you have heard it called. From here on I'll reference it as the Splitter as that's the job it is doing on the airflow that reaches it, whether it be splitting the airflow beneath or ontop of it or onward to the left/right Sidepods. The Splitter houses the Skid Block/Plank which is the FIA's way of mandating a flat floor, the piece of Jabroc that makes up the Skid Block must not be worn sufficiently during the race or the driver may be disqualified and so this limits the angle/rake the car can be raced at. The FIA also conduct a flex/load test on this area as during the mid 2000's teams exploited methods that allowed the area to deflect upward when it came into contact with the tracks surface. This deflection would allow a much more aggressive rake, meaning the then higher placed Front Wings were lowered toward the ground and the diffuser had a larger expansion ratio. Returning to it's relationship with the Front Wing and the Splitter is furnished vorticised airflow from the Y250 area from both the change in profile from the mandated section and also any other elements each team look to place in the area (With the prevailing trend for teams to place R Cascades and/or split their Wing profiles to generate vortices that lead onward to the Splitter area)
The Splitter itself generally has a section at it's outer edge that is designed to take these Vortices and send them onward along the edge of the transition between the Step and Reference planes. Whilst the remainder of the vortices (higher) are managed by the Sidepod undercut etc.

Above: a great shot of the RB9 showing not only the Diffuser but partially the Skid Block and Floor ahead of it 
So why do some teams appear to have good downforce but don't run with high rake? A good question, there is a tipping point at which it becomes fruitful to have more or less rake and in reality only the team will know where that lies. A Diffusers performance has to work over a wide speed and pitch range which both contribute to the Diffusers expansion, get the rake wrong and you can end up with the Diffuser losing efficiency or some cases stalling. If we imagine that exhausts could not contribute to the sealing of the diffuser then peak downforce generated in the Diffuser would occur at a much lower height (due to Ground Effect) and so this brings us back to the effects of the exhausts in determining whether to run with more or less Rake. As mentioned earlier in the article when referring to the joint between the Wing and Endplate, the same Vortex exists in the Diffuser (just flip the logic) with the Outer most Diffuser Strake acting as the Endplate and the Sloped section of Diffuser acting as the Wing. The Vortex created at the edge of the Diffuser helps to extract the airflow and as we discussed before if we lower the rear end and in turn the outer Diffuser Strake(Lower Rake) peak downforce is generated at a lower range. (Ie less airflow can move from outside the Diffuser into the Diffuser destroying the Vortex)
So how does increasing the Rake improve downforce? This is all based on the intensity of the exhaust plume being pumped between the rear wheel and Diffuser Strake. The exhaust plume acts as an extension of the Strake extending the Diffusers height whilst stopping airflow entering the Diffuser from the side and destroying the Vortex thereby increasing the available area of expansion for the Diffuser.

Rake's effect on the rest of the floor: Inevitably by increasing the rake you affect all parts of the car and a large benefactor in this enterprise is the floor of the car, with the Splitter now more acutely angled to the ground the airflow will be pushed aside more effectively as it tries to get both under and over the Splitter. Due to the nature of the regulations the Skid Block/Plank resides on the Reference Plane whilst the floor to it's left and right is placed 50mm higher on the Step Plane with a Vertical transition residing between the two. This leads to more expansion being available in the outer portions of the Diffuser and by this virtue we must see the Diffuser as having three components, the two outer channels and the central one. This is why we see the centralised section of the Diffuser with Strakes that reach down much further than the outer ones as controlling and shielding the Vortices generated in this section are imperative to the balance of the car. The vortice that has been dispatched from the Y250 zone at the front of the car exits in the same place in the Diffuser guided by the second most inner Strake with the most inner Strakes regulating the size of the vortice so that it doesn't break down (especially as teams tend to use the Starter Motor hole to also dispatch air through)
The outer Sections of the Diffuser generally have their walls (outside edge) tapering outward to maximise the Difusers area meanwhile at least one more control Strake will sit inbound on the centralized channel in order to control the vortices that are being created at the outer edge.
With Rake increased the requirement for the outer channels to be fed airflow is increased with the exhaust plume creating the most obvious interaction in the outer section just as was done when the rules permitted EBD. The exhaust plume (if directed correctly) not only fills the void between the tyre and the floor helping to 'Seal' the diffuser but ingresses into the outward channel helping to extract the airflow more quickly by enhancing the Vortex giving the effect of that region being closer to the ground.
Airflow to the outer channels of the diffuser is also dealt with by the floor and so when using more Rake adaptations must be made here too in order to fully extract the benefits of larger expansion. This will lead to changes in the lower edge design of the Bargeboard (In Front of the Sidepod) along with other changes to the forward section of the floor. Furthermore changing philosophy to the way in which airflow migrates along the side of the floor will not only effect the car in yaw but increase the Diffusers performance too. Using Red Bull as an example (as they are a team that tend to increase the Rake in their cars) a new Floor Scroll has been added to the RB9 that features a perforated edge, this perforation will increase the areas efficiency and push aside the airflow that the wheels have dispatched of upstream.

In Summary

Rake can be identified as an increase in downforce, however the effects of Rake can either be scaled as marginal or large. The crossover point of running the diffuser in ground effect and at a higher height are relative to the 'Sealing' effect being created by the exhaust plume. It could be argued that it's a trade off unless you can successfully create a large enough effect from the exhaust plume to 'Seal' a much larger area of the Diffuser's edge or indeed enhance the vortex being created in the outer edge of the Diffuser aiding in flow attachment. With raised Rake you then also have to redesign / profile the rest of the cars design too.
The 2011 variant of Blown Diffusers owed their success to the now banned off throttle maps and so creating that same 'Sealed' effect when the driver is entering the corner is the most difficult aspect for the teams to overcome when utilising additional rake. In the case of Red Bull (RB8/9) and now Lotus (E21) and Williams (FW35) we see the teams utilising Cross-Under Tunnels beneath their exhaust channels.



These help to separate the airflow above the floor giving the exhaust plume a clearer pathway to the gap between the rear wheels whilst migrating the airflow coming around the Sidepods/floor into the more centralised coke bottle area via the tunnels. This allows a transitional period between on and off throttle, smoothing out the loss of downforce as the Diffuser is robbed of it's 'Sealing' skirt. Furthermore we have seen that throughout 2012 as Red Bull made revisions to the rest of their aero scheme they also changed the quantity/geometry of the Cross-Under tunnels which undoubtedly mirrors the other changes when considering centre of pressure.
I suppose the other plausible solution to smoothing out the transition in downforce would be if the team could find a way in which to adjust the ride height of the car as it enters the braking phase. Lowering the car at the rear could lead to the Diffuser re-entering 'Ground Effect' and recovering some of the losses associated with the loss of downforce as the exhaust plume dissipates. This is obviously a difficult task as when the car brakes it will dive forward and so the teams would need a method of circumnavigating this to either raise the front of the car under braking or lower the rear. This is a method used in the active suspension days in order to keep the car in it's aero window and so is extremely difficult to replicate now but I do have a feeling we may be revisiting this topic soon.

I'll leave you with a brilliant video from @PeterDWindsor where he interviews James Allison (Lotus, Technical Director) on the topic of blown diffusers and moreover the differing solutions teams used when utilising exhaust gases (obviously Renault's FEE isn't applicable anymore, but it does highlight the need to think about centre of pressure shift during on and off throttle moments)
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3 Feb 2013
Infinti Red Bull Racing RB9 Launch - Technical Analysis

Red Bull's unveiling for all intents and purposes sets the benchmark in terms of design for 2013 with the other lead teams already showing that they have converged on ideas running through the RB5-RB8's lineage. I talked about Red Bull / Newey's adoption of halfshaft shrouding many times last season but the piece that really showed this was when I traced it's evolution through from the RB5 in the second part of my technical assessment of Red Bull.
The integration of the halfshaft within the lower wishbone has been seen on the McLaren, Force India, Ferrari and Sauber so far allowing the exhaust plume to pass un-encumbered over the rear of the cars floor, by doing this the teams are also raising the wishbone further clearing the airflow path.

Toward the end of last years campaign Red Bull installed a myriad of updates to the Red Bull with the key goal of exploiting DDRS (Double DRS). Unlike the Mercedes system Red Bull simply opted to further reduce drag at the rear of the car via the beam wing but with the other changes they made (Front Wing, Nosecone under belly, FOM camera's moved into the hammerhead position and exhaust ramp and cross-under tunnel rearrangements) they were able to create a more stable platform - http://somersf1.blogspot.co.uk/2012/10/red-bull-recent-development-analysis.html

The 2012 season for Red Bull uncharacteristically started on a low which we now know was due to the FIA altering it's perspective on the exhaust solution that Newey and the design team had prepared just prior to testing. I believe the idea behind their original system was the re-ingestion of exhaust gases through a section attached to the brake ducts allowing them to re-direct the airflow into the critical region between the rear wheel and diffuser wall. When this was restricted the team went back to the drawing board and redesigned the RB8 but with time before the start of the season at a premium the team struggled to correlate it's design between CFD, Wind Tunnel and real world scenarios leading a small downturn in fortune. This is why we saw a rise in comparable form of Mark Webber at the start of the season as he is able to extract more from a more squirrely rear end where as Sebastian thrives on a firmly planted aero car.

The question we must ask is how close will the unveiled RB9 car of today be to the one that features at Melbourne? Red Bull have in the past opted to show little at launch in favour of baselining the car at testing and then adding their aero configuration throughout the test scenario. It would appear from the outset that the RB9 also follows this path with the RB8's DNA fimrly scattered across the car. Fans and media alike were dissapointed to find that Red Bull were being very confrontational about pictures being taken of their 2013 challenger. Simultaneously the team released the following video via Youtube.



The first few minutes show the viewer some of the details that goes into making a Red Bull Racing car (see my article here on some of this: http://somersf1.blogspot.co.uk/2012/12/red-bull-racing-historic-technical.html)

With the media on lock down at the launch the quantity of good quality pictures available to assess the RB9 is limited but as usual the team also released the following images:

When compared to the RB8 renders (below) we can see that the car is clearly an evolution (albeit the RB8 renders show the car pre exhaust and cross-under tunnel)

Let's start from the front and work our way down the car

Front Wing: As usual on F1 launch cars thiese don't change drastically from their 2012 challengers but it's an area where i'm sure Red Bull will have invested time due to the increased load testing introduced throughout 2012.  Some minor alterations to the design of the top flap with the upper inner portion of the flap looking like it protrudes vertically and is has a more bulbous top edge. I suspect we will see a new design during testing.


In terms of the nose the frontal section of the nose carries the hammerhead appearance it's predecessor did at the end of 2012 courtesy of the FOM camera mounting positions.  The Nose tip itself once again droops down from the pylons forward in stark contrast to their rivals who seem intent on clearing as much space under the nose as possible.



Retained from the Singapore onward spec under the nose is the curved underbelly which goes some way to manipulating the airflow heading toward the keel and then onward to the Sidepods.  Newey and the team not one to shy away from thinking of aero over aesthetics have kept a step nose on the RB9.  Instead of the abrupt shelf like step with cooling slot on the RB8, the RB9 utilises the vanity panel to extend the step transforming it into a slope much like how Lotus have done with the E20/1.

As we can see from the 2 pictures the nosecone region tapers in toward the bulkhead allowing the step to also taper outwards. From the lower nose picture we can see how this sculptured piece of bodywork allows the air to migrate from the nose over the control arms.


As we can see from the blurry picture above it does appear the team may have adopted a slimline version of Saubers rearward facing duct (fed via an S duct from below the nose) I'll keep looking for a better image in the meantime

The Front Wing pylons have also been treated to some attention and are seemigly wider at the bottom following the McLaren trend (When viewed from the front). From the side the pylons also taper from the top down to their connection with the mainplane.


Moving along the car we can see that the Sidepods haven't been treated to a dramatic change in philosophy but the team have added a nice piece of detail on the floors edge.  The Floor Scroll is detached from the floor itself bar a few a few connecting strakes and courtesy of F1_Aero over on twitter he explains that ' It's designed to increase the draw under the front of the floor and provide a stronger floor edge vortex for floor sealing'


On top the Sidepods the airflow is conditioned by the same elements used last season

At the rear of the car, the launch version at least is treated to a similar exhaust and cross-under tunnel configuration used throughout 2012 with the halfshaft cover remaining and 3 Vertical strakes placed either side of the Coke Bottle region and under the shroud to help distribute the airflow.


Lastly we have the Monkey Seat which is fairly innocuous with the only real thing of design merit being the large perforation between the two wing sections it uses. It does however sit on a curved section of the Beam Wing which has been designed to allow air to pass between the Wing and Structure.

In summary just like all the launches that have preceded it the Red Bull car launch acted as a way of showing off commercial partners and so doesn't show it's hand, we must therefore wait til testing to truly see what they have up their sleeve.




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11 Jan 2013
2013 - F1 Car design trends, what's banned and what to look out for (DRD, DDRS, Pull Rod Suspension)

The 2013 regulations are somewhat similar to their 2012 counterparts with the exception of the FIA closing some loopholes used by teams to circumnavigate the rules in order to gain an advantage. 

Nosecone - Step Noses

In terms of aesthetics the teams will also have the option of covering up the 'Step noses' that became the centre of attention when the cars were first shown before testing in 2012.

The 'Step Nose' was born out of a requirement to allow airflow to pass relatively unencumbered toward the leading edge of the cars floor. The reason for the ungainly look is due to the difference in height allowable at the bulkhead and the nose tip. In order to gain the highest possible setting the nose became jaunted much to the dismay of many F1 fans. Aesthetics is not something that principally drives aerodynamicists and so the step adorned all but the McLaren and Marussia cars. The latter teams deciding to run the bulkhead of their cars lower both yielded throughout the season and adopted higher nose tips albeit without the 'Step'.

The 2013 regulations permit the use of a vanity cover (non-structural fairing of prescribed laminate) which allows the teams to effectively cover up the Stepped Nose returning it aesthetically to the regular nosecone shape F1 fans had come to know. This doesn't mean 'Step' noses have been eradicated as this is only a recommendation. Red Bull utilised the stepped area for driver cooling in 2012 rather than it's regular nose tip position, other teams may adopt this path in 2012 emulating the RB8. Furthermore as was the case for speculation toward the end of the season the nosecone and front wing pylons may be being flexed. Having a vanity cover placed over the a flexing nosecone could lead to failure of either part and more importantly the degradation of it's effect.

Above: Craig's image shows how a vanity cover may be applied to the nose of a 2013 car - his original article pertaining to this can be found here: ScarbsF1

Front Suspension


Ferrari caused another storm when they released the first images of the F2012 showing to the world their 2012 challenger would use Pull rod suspension at the front as well as the rear of the car. Pull rod suspension was last seen at the front of the car in a 2001 Minardi PS01 (Also driven by Alonso) In the early stages of the F2012's life it was clear the car wasn't as competitive as the Maranello team desired with many citing the pull rod front suspension as one of it's weaknesses. As time passed by it became clear that the suspension afforded the Ferrari team not only advantages of a lower CoG but also in the way the suspension responded with and treated the Pirelli tyres. Many other teams have since stated that they too will investigate the merits of applying pull rod suspension at the front of their 2013 challengers based on the relative success of the F2012.

Tyres

2012 saw 7 different winners from the first 7 races something that many fans angrily levelled at Pirelli's aggressive tyre strategy. The problems encountered by the teams early in 2012 were not all based on the compounds chosen by Pirelli though with the construction of the tyre causing just as many headaches. The construction of the front tyres lead to wear being a factor unilaterally causing insistences in how the tyre degraded. For 2013 Pirelli have once again changed both the construction and compounds on offer with the latter available for the teams to test at Interlagos. I wrote about this at the time: Pirelli tyre test - Interlagos However the important aspect is in regard to the construction of the tyre allowing for a larger contact patch something the teams will welcome based on their 2012 struggles.

Exhausts

Exhaust solutions have been a go to area for decades in terms of creating additional downforce but over the last few seasons the practice has rapidly increased. At the start of 2012 we saw 4 main variations for the teams to utilise exhaust gases.
 
Downwash Exhausts - Mercedes, Williams, Caterham & Marussia used these exhausts which also use the 'Coanda' effect but due to their placement it only attracts the airflow traveling over the Sidepod



'Coanda' Exhausts (Ramped and Wrap Around) Red Bull, Sauber & McLaren used this style of exhaust which later became the go to solution for the season with most of the grid converging on McLaren's style of exhaust


Engine Cover Exhausts – Lotus & Force India used these exhausts which were placed much higher on the car maximising horse power (maximum freedom for tuning lengths) and sending the exhaust plume higher as a result of the positioning.


Convergence Exhausts – Ferrari & Toro Rosso used these exits and looked to converge the exhaust plume with exiting radiator airflow

All of the designs have their own merits and would have undoubtedly have originally been chosen with regard to other factors aswell. Packaging, cooling and exhaust tune ability would have been the primary concerns for the designers sculpting their designs around these and aerodynamic demands. With 4 Engine suppliers on the grid all of these factors will change the approach used, meaning that adopting an exhaust solution in use by another team can lead to compromises in other key areas.

By the end of 2012 most of the field were running some form of 'Coanda' exhaust with the exception of Mercedes and Williams who had both trialled it but reverted to early season iterations with Williams sporting their abruptly ending Sidepod (Convergence Exhaust).

2013 will most likely see the grid converge on the same basic principle of 'Coanda' exhausts and instead of having to adapt to the style out of necessity they'll have more refined concepts designed with that layout as part of the cars blueprint. The reason I believe this will happen is the lead teams finished their campaigns running this type of exhaust but more importantly perhaps it allows for a similar effect to the EBD's we saw throughout 2010/11. Of course it's not as effective as a shrouded exhaust (2010/11 EBD) but the manipulation of the surrounding airflow leads to more airflow being drawn into the required area between the outer Diffuser wall and the tyre. Pushing airflow into this region encapsulates (Seals) the diffusers outer portion and stops tyre squirt from impinging on the diffusers flow. (Air is pushed sideways off the tyre and is sent latterally into the diffusers airflow disrupting the diffusers effectiveness)

It will be interesting to see if any of the other teams are bold enough to follow Red Bull endevours with their Cross-Under Tunnel. The team struggled with the concept initially and continued to revise the layout right up until the end of the season. (Although the latter alterations were more aimed at maximizing the DDRS system the team implemented in Singapore) The Red Bull ramp and cross-Under tunnel looked to separate the airflow regimes from above and from the side of the Sidepod by transporting the airflow from around the side of the Sidepod underneath the ramp and out of the car more centrally. This allowed the airflow from over the Sidepod to converge with the exhaust plume and move toward the gap between the Diffuser and Tyre. This of course is not it's only destination with the airflow passing between the tyre wall and the bottom of the engine cover, with it's life being made all the time easier by another Red Bull only item for 2012. Red Bull have historically shrouded the halfshafts where the exhaust plume would interact with them. This is a topic I look at in more detail in my recent technical assesment of the team: http://somersf1.blogspot.co.uk/2012/12/red-bull-racing-historic-technical_30.html This time however they went one step further using Vertical Floor Strakes mounted underneath the shrouds to help distribute the airflow and reduce boundary layer separation. I have heard rumour that Ferrari will also adopt a similar method for their 2013 challenger highlighting the fact they may adopt a exhaust/bodywork style similar to the RB8. It would however not surprise me if Ferrari weren't the only team to adopt the halfshaft shroud for 2013.

Sidepod Vortex Generators & Sidepod Wings

In order to maximise the airflow over the Sidepods team used these appendages throughout 2012. McLaren started proceedings with their twin vertical fins mounted on top of the Sidepod a feature that filtered throughout the teams with most running 2 and others fielding 3. Sauber however fancied another route placing horizontal winglets above the Sidepod in what I've previously described as looking like a leading edge slats (as used in aeronautics). In aeronautics slats are preferred over vortex generators when the stalling angle is too great to be surmounted by the latter. In the case of both Sauber and McLaren it would seem that the width of the Sidepod cannot sustain enough Vortex Generators to surmount the Length / Angle of Attack of their Sidepod and so they used Sidepod Wings instead. An interesting development that could have already been in play on the C31 and MP4-27 would be flexible Sidepod Slats, if these were to deform at higher speed thereby closing the gap between it and the front of the Sidepod it could lead to the area becoming more efficient throughout the whole speed threshold. Interestingly Toro Rosso combined both effects as the frontal part of the STR7's Sidepod was detached from the latter part to which they then added Vortex Generators on top of.


Sidepod Airflow Conditioners

Usually these items sit on the outside edge of the floor next to the Sidepod and manage the airflow that stagnates around the Sidepod co-er sing it along the floor instead of off the floors edge. As with every component on an F1 car the longer the item is the more boundary layer will build up causing unstable flows. To make their conditioners more effective Ferrari, Caterham and Lotus all used twin element conditioner's making for a more efficient design. This isn't to say the other teams need to have twin elements in 2013 but tells us more about how the aforementioned teams tried to rectify a deficiency up stream. Sidepod Airflow Conditioners have been around for about 6 or so years no and have evolved considerably throughout this time frame so expect more of the same for 2013.

DDRS & DRD



DDRS (Double DRS) was pioneered by Mercedes at the start of 2012 and was immediately requested to be banned by the other teams. They feared that like the F-Duct that had appeared in 2010 it's design that was an intrinsic part of the W03 would be difficult and costly to develop. Furthermore it was believed that it could give Mercedes an advantage at the start of the 2012 campaign. The system which was as simple as the forethought to lay tubing that spanned from the front to rear wings allowed the team to reduce drag on the Front Wing aswell as the rear when DRS was active. The system however could not surmount the other design deficiencies of the W03 leaving it just one win all season. Red Bull keen to mount a charge at the end of the season also saw an advantage to using DDRS. The Red Bull system however didn't use the secondary function to reduce drag at the front of the car but instead further reduced drag at the rear. As with the Mercedes DDRS when DRS was activated a hole emerged in the Rear Wing Endplate that sent air down a cavity in the Endplate to the Beam Wing. Small holes in the Beam Wing then allow the airflow characteristics around the Beam Wing to change further reducing downforce and drag. DDRS has been banned for 2013 with the FIA disallowing use of the the top flap for secondary purposes, furthermore they have also redefined the rules pertaining to ducts leading from the front of the car.



DRD (Drag Reduction Device) as coined by myself and Craig Scarborough is a totally independent system to DDRS. The mainstream media unfortunately confused many F1 fans calling the original Lotus 'Device' DDRS which was the reason for us coining it DRD. Sky Sports commentator David Croft picked up on this and towards the end of the season referred to it as DRD when Lotus and Mercedes used theirs in free practice sessions.
DRD is passive and requires no interaction from the driver to activate it, the system is tuned to 'Stall' the rear wing at a predefined speed threshold. This created a problem for both Lotus and Mercedes who tested DRD frequently throughout the season but failed to race it.

In terms of a speed advantage as the device is passive the point at which it switches from producing downforce to a stall is imperative.  The RW80's / F Ducts driver interaction gave the switching capacity over to the driver allowing them to activate the system when they felt comfortable with the level of downforce available leading to around a 10KPH-15KPH gain in top speed.  In order to create a safety buffer the teams will have to be much more lenient with DRD as you don't want it stalling the rear wing on the exit of a corner too early.  This would lead to a lower drag reduction value but could still see the teams gaining upto around 8KPH in top speed.

My theory (below) is DRD produces additional downforce until the prescribed speed threshold (in much the same way McLaren's RW80 / F Duct did):

  • The rear wing planes are set at a higher angle of attack than usual
  • Air entering the airbox or additional airbox 'Ears' (Car dependant) and running through the engine cover to the Pylon.
  • The airflow then runs up the pylon and exits through slots cut into the side of the pylon, tangentially blowing across the mainplane.
  • This airflow allows the rear wing to operate up to the speed threshold whereby the airflow being received from the pylon cannot sustain the angle of attack the wing is set at. This leads to the wing stalling, detaching the airflow completely and reducing both downforce and drag.

Mercedes version of DRD featured a pylon that didn't extend to join with the mainplane allowing the slots to blow onto a wider proportion of the mainplane.


As DRD was only used in testing during 2012 it's difficult to ascertain it's true potential but with unlimited DRS usage now removed for Free Practice & Qualifying in 2013 the potential for additional drag reduction will appeal to the teams. At the young drivers test in Abu Dhabi both Red Bull and Sauber tested their own variety of DRD's with Toro Rosso also placing an appendage on their Monkey Seat simulating the position of a Double DRD.
 

DRS has been reduced to usage only within the specified zone(s) at each GP this year with it previously having unlimited usage.  This will have an effect on how the teams design their rear wing planes in 2013 with the DRS delta now changed.  Many teams were skewing their setup to allow for a maximum DRS gain but with the likely introduction of DRD and the rule changes this approach will probably alter.

Lastly just a quick mention about Sauber's test package used at the young drivers test in Abu Dhabi, the team introduced an exit on the side of the Sidepod to assist in attachment along the length of the Sidepod  a feature that may well be part of many of the 2013 designs that go along the Ramped bodywork lines.

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