F1 2011 Technical Regulations – Detailed and Explained

Finally the FIA have published the detail of the 2011 technical regulations. There were no major surprises amongst the rules. There being rules to effectively ban: double diffusers, F-ducts & slotted rear wings. Newly introduced were the mandated weight distribution and adjustable rear wing. 

There’s a lot to cover, so I wont cover every rule change and neither can I cover them in detail. but here’s the main points (with the rule in italics).

The full FIA regulations are detailed here:  FIA F1 2011 Technical Regulations

 

Ban on connected shark fins

Another route to banning F-ducts, as well as a move to limit the ever expanding rear fin, the rule prevents any bodywork reaching the rear wing.

“3.9.1 No bodywork situated between 50mm and 330mm forward of the rear wheel centre line may be more than 730mm above the reference plane.”

Ban on slots in the beam wing

With the exception of the central 15cm, the beam wing cannot have a slot that widens internals to create a blown slot. Only Williams raced this last year, but the practice has prevented. This reinforces the fundamental rule that the lower wing should only be formed of one element

“3.10.1 Any bodywork more than 150mm behind the rear wheel centre line which is between 150mm and 730mm above the reference plane, and between 75mm and 355mm from the car centre line, must lie in an area when viewed from the side of the car that is situated between 150mm and 350mm behind the rear wheel centre line and between 300mm and 400mm above the reference plane. When viewed from the side of the car no longitudinal cross section may have more than one section in this area.
Furthermore, no part of this section in contact with the external air stream may have a local concave radius of curvature smaller than 100mm.
Once this section is defined, ‘gurney’ type trim tabs may be fitted to the trailing edge. When measured in any longitudinal cross section no dimension of any such trim tab may exceed 20mm.”

Ban on slots in the rear wing


As with the beam wing, the upper rear wing is prevented from having slots extending beyond the central 15cm. This prevent F-ducts or other blown slots, the latter which have been exploited for several years.

“3.10.2 Other than the bodywork defined in Article 3.10.9, any bodywork behind a point lying 50mm forward of the rear wheel centre line which is more than 730mm above the reference plane, and less than 355mm from the car centre line, must lie in an area when viewed from the side of the car that is situated between the rear wheel centre line and a point 350mm behind it.
With the exception of minimal parts solely associated with adjustment of the section in accordance with
Article 3.18 :
- when viewed from the side of the car, no longitudinal cross section may have more than two sections in this area, each of which must be closed.
- no part of these longitudinal cross sections in contact with the external air stream may have a local concave radius of curvature smaller than 100mm.
Once the rearmost and uppermost section is defined, ‘gurney’ type trim tabs may be fitted to the trailing edge. When measured in any longitudinal cross section no dimension of any such trim tab may exceed 20mm.
The chord of the rearmost and uppermost closed section must always be smaller than the chord of the lowermost section at the same lateral station.”

Limit on Rear wing support pylons

The number, thickness and cross-section of the rear wing support pylons are now more tightly controlled.

“3.10.9 Any horizontal section between 600mm and 730mm above the reference plane, taken through bodywork located rearward of a point lying 50mm forward of the rear wheel centre line and less than 75mm from the car centre line,
may contain no more than two closed symmetrical sections with a maximum total area of 5000mm2. The thickness of each section may not exceed 25mm when measured perpendicular to the car centre line.
Once fully defined, the section at 725mm above the reference plane may be extruded upwards to join the sections defined in Article 3.10.2. A fillet radius no greater than 10mm may be used where these sections join.”

 

Clarification of the starter motor hole


After some teams were exploiting oversized starter motor holes in the diffuser to create a slotted effect, the FIA clamped down with a clarification. This has now been written into the rule book.

“3.12.7 No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a point 350mm rearward of it may be more than 125mm above the reference plane. With the exception of the aperture described below, any intersection of the surfaces in this area with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car.
An aperture for the purpose of allowing access for the device referred to in Article 5.16 is permitted in this surface. However, no such aperture may have an area greater than 3500mm2 when projected onto the surface itself and no point on the aperture may be more than 100mm from any other point on the aperture.”

 

Ban on Double Diffusers (DDD) and Open Exhaust Blown Diffusers (EBD)

Due to a previous weakness in the rules defining the underfloor, teams were able to exploit this to create the double diffuser. Double diffusers were only possible as an opening could be created in the gap been the reference plane, step plane and the diffuser. Now the rules close this avenue off.
Additionally this opening allowed teams to open up the front of the diffuser to blow the exhaust through for an even greater blown diffuser effect. This rule also prevents this opening in all but the outer 50mm of the split between the diffuser and the floor.
One additional clarification is that the suspension must not form any of the measured point for the under floor. Previously the minimum height was exploited by some teams placing wishbones or Toe-Control arms across the top an opening in the diffuser.

“3.12.9 In an area lying 450mm or less from the car centre line, and from 450mm forward of the rear face of the cockpit entry template to 350mm rearward of the rear wheel centre line, any intersection of any bodywork visible from beneath the car with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car. When assessing the compliance of bodywork surfaces in this area the aperture referred to in Article 3.12.7 need not be considered.

3.12.10 In an area lying 650mm or less from the car centre line, and from 450mm forward of the rear face of the
cockpit entry template to 350mm forward of the rear wheel centre line, any intersection of any bodywork
visible from beneath the car with a lateral or longitudinal vertical plane should form one continuous line
which is visible from beneath the car.
3.12.11 Compliance with Article 3.12 must be demonstrated with the panels referred to in Articles 15.4.7 and
15.4.8 and all unsprung parts of the car removed.”

 

Driver operated F-duct

Even though the loop holes in the rear wing regulations have been closed, this additional new regulation prevents the driver influencing aerodynamics. So that other driver controlled F-duct type devices cannot be exploited other areas, such as: front wings, sidepods or diffuser.

“3.15 With the exception of the parts necessary for the adjustment described in Article 3.18, any car system, device or procedure which uses, or is suspected of using, driver movement as a means of altering the aerodynamic characteristics of the car is prohibited.”

 

Ban on movable splitters

As with some other rules, this is a 2010 clarification now added to the regulations. Its thought that teams were allowing their splitter to flex upwards, to allow the car to run a more raked attitude and lower front wing ride height. There are now more stringent tests and restrictions on the splitter support mechanisms.

“3.17.5 Bodywork may deflect no more than 5mm vertically when a 2000N load is applied vertically to it at three different points which lie on the car centre line and 100mm either side of it. Each of these loads will be applied in an upward direction at a point 380mm rearward of the front wheel centre line using a 50mm diameter ram in the two outer locations and a 70mm diameter ram on the car centre line. Stays or
structures between the front of the bodywork lying on the reference plane and the survival cell may be present for this test, provided they are completely rigid and have no system or mechanism which allows non-linear deflection during any part of the test.
Furthermore, the bodywork being tested in this area may not include any component which is capable of allowing more than the permitted amount of deflection under the test load (including any linear deflection above the test load), such components could include, but are not limited to :
a) Joints, bearings pivots or any other form of articulation.
b) Dampers, hydraulics or any form of time dependent component or structure.
c) Buckling members or any component or design which may have, or is suspected of having, any non-linear characteristics.
d) Any parts which may systematically or routinely exhibit permanent deformation.”

 

Driver adjustable rear wing


The driver adjustable front wing is now deleted from the rules and instead the rear wing is now driver adjustable. This is because the expected benefit of greater front wing angle never provided the driver with more grip when following another car. The front flap adjustment was much more a solution to tune the cars handling in between pitstops. The TWG found that the loss of drag from the rear wing was a more effective solution to allow the following to overtake. Now the rear wing flap can pivot near its rear most point and open the slot gap from 10-15mm to up to 50mm. Opening this gap unloads the flap and reduced both downforce and drag.
This being controlled by the timing gap to the car ahead and managed by the FIA. So there’s two ways the driver can use the system. Firstly in free practice and qualifying the rear wing is solely at the control of the driver. They can adjust the wing at any point on the track and any number of times per lap. So for the ideal lap time, as soon as the car is no longer downforce dependant (straights and fast curves) the driver can operate the wing, just as they did with the F-duct. Although a small complication to the driving process, at least their hands remain on the wheel and not on a duct to the side of the cockpit.
Then in the race the wing cannot be adjusted for two laps, then race control will send signals to the driver via the steering wheel, such that when they’re 1s or less behind another car at a designated point on the circuit, the rear wing can be trimmed out. The wing returns to the original setting as soon as the brakes are touched.

“Furthermore, the distance between adjacent sections at any longitudinal plane must lie between 10mm and 15mm at their closest position, except, in accordance with Article 3.18, when this distance must lie between 10mm and 50mm.”

3.18.1 The incidence of the rearmost and uppermost closed section described in Article 3.10.2 may be varied whilst the car is in motion provided :
- It comprises only one component that must be symmetrically arranged about the car centre line with a minimum width of 708mm.
- With the exception of minimal parts solely associated with adjustment of the section, no parts of the section in contact with the external airstream may be located any more than 355mm from of the car centre line.
- With the exception of any minimal parts solely associated with adjustment of the rearmost and uppermost section, two closed sections are used in the area described in Article 3.10.2.
- Any such variation of incidence maintains compliance with all of the bodywork regulations.
- When viewed from the side of the car at any longitudinal vertical cross section, the physical point of rotation of the rearmost and uppermost closed section must be fixed and located no more than 20mm below the upper extremity and no more than 20mm forward of the rear extremity of the area described in Article 3.10.2 at all times.
- The design is such that failure of the system will result in the uppermost closed section returning to the normal high incidence position.
- Any alteration of the incidence of the uppermost closed section may only be commanded by direct driver input and controlled using the control electronics specified in Article 8.2.
3.18.2 The adjustable bodywork may be activated by the driver at any time prior to the start of the race and, for the sole purpose of improving overtaking opportunities during the race, after the driver has completed a minimum of two laps after the race start or following a safety car period.
The driver may only activate the adjustable bodywork in the race when he has been notified via the control electronics (see Article 8.2) that it is enabled. It will only be enabled if the driver is less than one second behind another at any of the pre-determined positions around each circuit. The system will be disabled by the control electronics the first time the driver uses the brakes after he has activated the system.
The FIA may, after consulting all competitors, adjust the above time proximity in order to ensure the stated purpose of the adjustable bodywork is met.”

 

Mandated weight distribution

Along with the supply of Pirelli control tyres they will be matched to a mandatory weight distribution. Now the cars minimum weight is 640Kg, the specified minimum axle weights, equate to a weight distribution ranging between 45.5-46.7% on the front axle. This is a few percent behind the typical 2010 loadings.

“4.2 Weight distribution :
For 2011 only, the weight applied on the front and rear wheels must not be less than 291kg and 342kg respectively at all times during the qualifying practice session.
If, when required for checking, a car is not already fitted with dry-weather tyres, it will be weighed on a set of dry-weather tyres selected by the FIA technical delegate.”

 

Double wheel tethers

For safety a doubling of the wheel tethers has been regulated. Each tether needs to pass through a different suspension member and have its own mounting points on the upright and the chassis. There’s not expected to be any performance impact with this. But the tethers are somewhat heavier, so they and the side intrusion panel are part of the reason for the greater minimum weight limit.

“10.3.6 In order to help prevent a wheel becoming separated in the event of all suspension members connecting it to the car failing provision must be made to accommodate flexible tethers, each with a cross sectional area greater than 110mm². The sole purpose of the tethers is to prevent a wheel becoming separated from the car, they should perform no other function.
The tethers and their attachments must also be designed in order to help prevent a wheel making contact with the driver’s head during an accident.
Each wheel must be fitted with two tethers each of which exceed the requirements of 3.1.1 of Test Procedure 03/07.
Each tether must have its own separate attachments at both ends which :
- are able to withstand a tensile force of 70kN in any direction within a cone of 45° (included angle) measured from the load line of the relevant suspension member ;
- on the survival cell or gearbox are separated by at least 100mm measured between the centres of the two attachment points ;
- on each wheel/upright assembly are located on opposite sides of the vertical and horizontal wheel centre lines and are separated by at least 100mm measured between the centres of the two attachment points ;
- are able to accommodate tether end fittings with a minimum inside diameter of 15mm.
Furthermore, no suspension member may contain more than one tether.
Each tether must exceed 450mm in length and must utilise end fittings which result in a tether bend radius greater than 7.5mm.”

 

No more shaped wheel spokes

After the static front wheel fairings that abounded in 2009, were banned and the wheel design homologated, there must have been some surprise that Ferrari managed to create an aerodynamic wheel shape in 2010. This is partly limited now by the restriction on surface area for spokes and shaping. The limited only allows 13% of the wheel centre to be spoked, meaning that a ten spoke wheel has to have spokes just 16mm wide.

“12.4.6 When viewed perpendicular to the plane formed by the outer face of the wheel and between the diameters of 120mm and 270mm the wheel may have an area of no greater than 24,000mm2.”

 

Clarification of mirror positions

Again when the FIA clarify a rule or make a change for safety reasons, we don’t get to see the detail of this change until its put into the regulations. The removal of outboard mirrors was brought in early last year and now the mirrors can effectively be no more than 27.5cm from the cockpit opening

“14.3.3 All parts of the rear view mirrors, including their housings and mountings, must be situated between 250mm and 500mm from the car centre line and between 550mm and 750mm from the rear edge of the cockpit entry template.”

 

Ban on blade roll structures

Mercedes surprised many with their blade-like roll structure, reducing the obstruction to the rear wing and allowing for a much shorter inlet tract for the engine, the solution was likely to be copied. A minimum cross section forced teams to have a wider section above the drivers head, negating the fundamental benefit of the solution

“15.2.4 The principal roll structure must have a minimum enclosed structural cross section of 10000mm², in vertical projection, across a horizontal plane 50mm below its highest point. The area thus established must not exceed 200mm in length or width and may not be less than 10000mm2 below this point.”

 

Dash roll structure point maximum height

With the cockpit opening fixed at 550mm, teams have often raised the front of the chassis around the dash bulkhead to create a raised nose. In the first of several limits for both 2011 and 2013, with even more stringent plans for 2013, the height of the front of the chassis is now being controlled. The limit for this point is now 670mm, still some 120mm above the cockpit opening.

“15.2.3 The highest point of the second structure may not be more than 670mm above the reference plane and must pass a static load test details of which may be found in Article 17.3.”

 

Limit on front chassis height

As already explained teams raise the position of the front (AA) and dash (BB) bulkheads to create space under the nose for airflow to pass in between the front wheels and reach the rear of the car. The trend for “V” sections noses, introduced on the Red Bull RB5 in 2009, makes the front of the chassis even higher, often being visible above the height of the front tyres (~660mm). Now both these bulkheads need to be at 625mm, some 75mm above the cockpit opening.

“15.4.4 The maximum height of the survival cell between the lines A-A and B-B is 625mm above the reference plane.”

 

Limit on shaped Rear Impact Structures


Since the 2009 aero rules, teams have been shaping the rear impact structures into ever more curved shapes to lift it clear of the diffuser and pass it underneath the beam wing. The tail of this structure must be centred at 300mm high, to prevent extreme banana shaped structures, this rule forces the structure to vary by no more 275mm.

“Furthermore, when viewed from the side, the lowest and highest points of the impact absorbing structure between its rear face and 50mm aft of the rear wheel centre line may not be separated vertically by more than 275 mm.”

McLaren – Analysis: New F-duct for Suzuka

 

In preparation for the final races, McLaren have developed another iteration of their F-duct rear wing. The new version places the stalling slot onto the rear face of the main plane of the rear wing, where the previous versions had all placed the slot on the rear face of the flap. This is a subtle change and effects the way the wing stalls to create improve aero efficiency (i.e. more straight-line speed, or more downforce for a given top speed).

F-ducts work as they reduce the drag created by the rear at speed, this drag limit’s the top speed the car can achieve for a downforce level. The more downforce the wing makes, the more drag is created and hence the lower the top speed. Although a larger wing creates more frontal area and hence presents more of an obstruction to the airflow, it is in fact the drag induced the unseen air spilling off the wing that’s creates most of the rear wings drag. In fact an F1 wing despite looking so streamlined creates more drag than a solid block of the same dimensions. This is because an F1 wing is so highly loaded as it strives to create huge amounts of downforce from such a small surface area, that the air coming off the wing creates an invisible extension to the wings frontal area. Created by both the airflow rising all but vertically off the centre part of the rear wing and then the even more draggy vortices spiralling off the wing tips. These vortices are often seen in wet conditions and used to be seen as a sign of an efficient wing, but are in fact hugely detrimental to the downforcedrag coefficient of a rear wing. This is why we see such efforts to reduce wing angles near the endplates and team make the slits in the endplates, as these are all aimed at reducing these vortices.

Drag is created by the wings upwash and the vortices spilling from the wing tips

An ideal situation would be a wing with steep angles of attack for downforce in the corners, where drag is of little consequence. Then a nice flat wing for the straights, where less drag improves top speed and downforce is not required to give the car grip. Without being legally able to move the wing itself(albeit this will allowed in 2011) there has no mechanism to create this effect in F1.

When the wing is stalled the airflow breaks up, preventing the drag inducing upwash and vortices

Teams have known for a long time that stalling the rear wing drastically reduces downforce and as a result reduces drag. This is because the large flow structures coming off the wing break up and shed the drag inducing effect they have. Many teams have tried to exploit the rules by flexing their rear wings to create just such an effect, but the FIA has outlawed this via a number of deflection tests and latterly the slot gap separator.

McLaren have now found that they can stall the rear wing, if they blow airflow out of a slot at right angles to the underside of the rear wing. But this in itself cannot be exploited unless there is a means to switch the airflow on and off. With the driver controlled F-duct, controlling the flow either to the stalling slot or to a neutral outlet, McLaren can achieve the ideal situation of a downforce wing setting for corners and low drag for the straights.

The driver controlled Fluid switch directs flow to the wing or the neutral outlet

By the driver controlling a duct that affects the flow through a ‘fluid switch‘, which is a “V shaped duct behind the roll hoop, flow can either pass to the slot or a secondary duct exiting in the low pressure region well away from the upper rear wing.

When disengaged the F-Duct sends flow through the lower branch, the upwash and vortices continue to create dragWhen the duct is disengaged airflow passes out of the duct which exits just above the beam wing. In this mode the rear wing has the flow attached and creates downforce and with it drag.Blowing the flap stalls the wing to reduce drag

When the F-Duct is disengaged air passes from the roll hoop inlet into the Fluid switch.  From there the air flows both into the low level nuetral outlet and partly into the cockpit. When the driver covers this cockpit control duct, the change in back pressure makes fluid switch alter the direction of the roll hoop flow, to pass into the duct towards the rear wing.

When the cockpit duct is covered air instead passes to the rear wing slot

When the driver engages the F-duct the airflow alters inside the fluid switch to send the air out of the stalling slot. This breaks up the vortices shed from the rear wing and reduces downforce and drag. McLaren initially had this full width slot towards the trailing edge of the flap, the airflow stalls quite late as it passes under the wing and the most likely effect of this is that airflow can reattach quickly when the duct is disengaged. Its also possible that a downside to this, as the wing stalls quite near the trailing edge there may still be some drag induced by the general upwash from under the wing.

Blowing the main plane stalls the wing earlier and may even further reduce drag

When Sauber copied the F-duct at the 2010 Australian GP, they had their F-duct stall the wing via a stalling slot in the main plane of the rear wing. While Ferrari and Red Bull followed McLaren with a flap stalling F-duct, Force India, Renault and latterly Toro Rosso have gone the way of a main plane stalling solution. By stalling the wing much further upstream, its possible that the disruption to the airflow further reduces the upwash, in turn reducing drag even further. On the downside the wing may take longer to see the flow fully reattach when the duct is disengaged.

McLaren appear to have seen a benefit in the main plane blown effect.  Although the solution has required new ducting and a new rear wing, it will only see at most three races before F-ducts are banned for 2011.  Such is the cost of fighting for the championship this year.

All the workings of an F-duct can be seen here

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Septembers Technical updates

I’ll compress this months work into one post for simplicity. For updates on F1 technology have a look at the following outlets: Automoto365.com, Motorsport Magazine and Race Engine Technology magazine.

Automoto365.com – Singapore Tech Desk
All the technical devleopments from singapores night race.
- McLarens front wing and nose cone (thanks to bosyber comments on this blog)
- Red Bulls updates
- Mercedes Bargeboards
- Williams Frotn wing
- plus more from Renault and Toro Rosso

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=10&seasonid=21&nextMode=ExclusiveNewsForm&news_id=42469

Motorsport Magazine – F1′s Aero Tricks

I’ve illustrated this article on this years must have developments: F-ducts, Exhaust Blown Diffusers and deflecting splitters.

http://www.motorsportmagazine.co.uk/2010/09/30/latest-issue-%E2%80%93-november-2010/

Race Engine Technology


What lies inside a contemporary Formula One engine? Toyota have given Race Engine Technology full access to their current RXV-08 F1 engine. This issue contains the most detailed technical article ever published on a current F1 engine. A 16 page article covering all aspects of the Toyota Formula One engine in a level of detail you will have never experienced before. RET have been given unprecedented access to the engine with the full co-operation of the entire technical team.

http://www.highpowermedia.com/mall/productpage.cfm/RET/2050/352560

Valencia: Technical review now Automoto365.com

 

My Technical review is now online at Automoto365.com.  With the latest updates across the grid.

http://bit.ly/aGG7yC
or
http://f1.automoto365.com/news/controller.php?lang=en&theme=default&team_id=0&month=07&seasonid=21&nextMode=ExclusiveNewsForm&news_id=41314

Valencia: Technical Review now on Racecar-Engineering.com

My Technical review is now Racecar Engineering Magazines Website. With News on the Ferrari, Renault and Mercedes blown diffusers, Red Bulls and williams Vaned double diffusers, Everyones f-ducts and all the new bits on the cars including Ferrari, McLaren, Renault and Williams.

http://bit.ly/cy1Q3H
or
http://www.racecar-engineering.com/articles/f1/475053/f1-2010-european-gp-technical-updates.html

My work also gets published along with other technical motorsport articles in each months Racecar Engineering Magazine…

Subscribe to the paper edition: Racecar Engineering Subscription
Subscribe to the digital edition: Racecar Engineering digital Subscription

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China: Mercedes new rear wing

Just as Ferrari have joined Sauber in trying to catch up with McLarens F-duct blown rear wing, Mercedes also appear to be in the early stages of testing their own solution.  While not as conclusive in proving there is an f-duct as with Ferraris bodywork, Mercedes do have a duct that links the main plane of the wing to the Flap.   However this may not be the complete solution, as there does not appear to be a duct linking this rear wing fin to the chassis.
 
Mercedes are one of the few teams (and Brawn before them) not to have raced a shark fin engine cover.  It could that either Mercedes are awaiting the shark fin cover to run the fully ducted flap and that this test was just a structural test for the now largely hollow slotted rear wing flap.  Or that their solution will duct the airflow up through a central wing support strut (currently absent on this car) or less likely through the wings endplates.  As this would mean the beam wing would also need to be hollow and some how connected to the F-duct.  As Mercedes run a fully exposed beam wing there is little connection between it and the chassis.
 
It also been noted that the Mercedes ran pipework from the front of the sidepods backwards towards the rear of the car and then up inside the rear wing endplate.  These are more likely to be wiring or pressure for sensors, than the duct itself as they are very narrow in gauge and unlikely to pass enough airflow to alter the rear wings aerodynamics.
 
Mercedes do have one advantage, their monocoque has usefully placed apertures by the side of the pedals, these holes have already sported scoops for driver cooling, these could be modified to be the driver interface with the duct to the rear wing.
 
It is not likely we will see the full Mercedes F-Duct solution until the other major updates arrive at the next race in Spain.
 
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China: Ferrari introduce a blown rear wing

In the first practice in China, Ferrari unveiled their new rear wing, which features a blown flap in a similar manner to McLaren.  Mclaren have infamously produced the F-Duct which uses a duct controlled by the driver to alter airflow around the rear wing to stall it at high speed to gain more top speed.  Is this an F-Duct as used by McLaren, may be not.

Unlike the McLaren and Saubers set ups, the Ferrari solution does not appear to have the driver interacting with the duct.  Instead the wing is fed with airflow coming from an inlet high up on the engine cover, well away from the drivers reach.  It is possible that the there is additional ducting inside the car that does allow the driver to control airflow through the duct.  But so far no signs of a driver controlled inlet around the cockpit are evident.  It could be Ferraris set up uses pure aerodynamics to affect the duct, by choking at high speed (safely well above the maximum corner speed). 

Latest: Alonso to Autosport.com  “I had nothing inside the cockpit because the system is not complete. We tested the engine cover to compare it with the standard one. I didn’t notice anything. I guess there will some new numbers from an aero point of view.”

We will update this post as more info emerges over the weekend.

Sauber: F-Duct detail

The duct on the sidepod runs through the slot in the rear wing and possibly the cockpit too

Having declared they had rushed through their own version of the F-duct, we can speculate how it might work.  We know that the McLaren duct is vented into the cockpit around the drivers legs.  Then it is their leg that closes the duct to feed the rear wing.  This alters; the flow through the slot in the rear wing flap, stalling the wing, reducing drag and increasing top speed.

Sauber have already run with a vented rear wing, theirs uses the inlet on the front of the wing, to blow through a slot underneath the wing.  This allows the rear wing to be steeper without stalling, for more downforce.  Their new shark fin bulging with the duct moulded inside it, feeds into this same slot.  they could be aiming to blow even more airflow through the slot or like McLaren alter the flow to stall the wing. 

But the flow through McLarens slot is driver controlled, so Sauber need to find a way to ‘switch’ the flow on and off.  This could be done purely by the airflow being overcome by the drag creating inside the tortuous duct and hence cutting off the flow above a certain airspeed.  Or they have found a way to vent the duct into the cockpit. 

the hollow side impact spar coud lead into the cockpit to allow the vent to closed

In Saubers case the duct does not pass through the footwell of the cockpit as in McLarens case, so how might they enable the driver to seal the duct?  The placement of the duct may be gives us a clue.  It is possible that an opening exists within the side ofthe moncoque.  Sited near both the ducts inlet and running accross the frotn of the sidepod to the side of the tub is the impact spar, this could lead to an opening into the cockpit and allow the drivers elbow to seal the duct and redirect the airflow.  Its not normal for teams to want to create any opening in the side of the chassis to improve stiffness and crash protection.  But it is possible.

Therefore the driver presses his elbow against the opening at high speed to achieve the same stall as McLarens drivers get with their leg.

Sauber to trial an F-Duct

As we can see in these pictures Sauber have indeed prepared an F-Duct for testing in Australia. More details from the team are on Autosport.com (http://bit.ly/cSXnjh ). It seems the team are now more agile once again since they have shed the BMW ownership & management. Perhaps ex-McLaren test driver Pedro De La Rosa brought some ideas to the team

from the limited pcitures we have, we can see that the lefthand sidepod shoulder has an inlet mouded into it. this presumably feeds back through the sidepod and around theairbox to run int the shark fin. The ducting inside the sharkfin is quite evident and ends by connecting to the rear wing. it appears to attach to the mainplane (not the flap as with McLarens set up) somewhere behind the exisitng blown slot inlet.

From what we can see, it cannot becontrolled by the driver, so the duct may not be trying to do the same thing as the McLaren. Either the team rely on a a puely aerodynamic way to control the rear wing stalling, such as the duct choking at high speed and cutting off the flow the slot. Or the duct merely adds mass flow to the exisiting blown slot (raced in Bahrain) to allow the wing to be run even steeper and create yet more downforce. We will need mor eimages to be sure what Sauber are trying here.