Williams – Rear wing mount and reports of lateral movement

Williams have a unique rear end set up, with the rear wishbone and rear wing mounting to the same pylon. In early tests other drivers and media suggested the rear wing moving laterally and this was related to the lack of stiffness in this pylon. However Sam Michael has refuted these claims and looking at the rear wing set up, you can see where the movement came from.

Due to its low gearbox casing, the rear leg of the top rear wishbone mounts to a vertical metal extension of the gearbox. The structure then continues vertically in the form of a carbon fibre strut, which mounts the top rear wing. Normally teams will also support the beam wing with sizeable mount to the top of the rear impact structure. As part of Williams ‘waisted’ approach to structures at the back of the car, the beam wing ‘floats’ above the impact structure. Thus aero loads from this device pass upwards through the endplates into the top rear wing and consequently into the vertical pylon back to the chassis. In early tests the endplates were not able resist the lateral loads the beam wing exerted on the assembly and as a result the lower of the wing moved laterally. Williams had already accounted for this with a small metal stay (illustrated – yellow) between the vertical pylon and the beam wing. Such were the cornering loads around Valencia, this was unable to steady the wing. So Williams added links from the endplate to the diffuser. This greatly reduced the movement and no negative comments have merged about the structure around the back of the car since.

Happy New Year – RedBull RB6 Illustration (Wallpaper)

I’ve been drawing this big detail – big scale illustration of the RB6 as a prelude to a prediction of the 2011 car designs.  So I’d thought I’d post the 2010 RB6 version up as a wallpaper in mono at 1280 resolution.  I’ll do larger sizes on request with or without logos (mail me).

Have a great New Year and thanks for supporting me in my first year Blogging and Tweeting.  Next year will be my tenth covering the technicalities of the sport, so I’ve got some new ideas up my sleeve.

Scarbs…

and without Logos…..

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.”

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

Splitters – New deflection test and construction

As explained in my previous post, the front splitter (bib or T-tray) has come in for some further attention from the FIA’s scrutineers. In order to run the front wing lower for greater downforce, its believed teams are allowing the splitter to deflect upwards. Although there is an existing test where the leading edge of the splitter is subject to a vertical load of 100kg and must not deflect more than 5mm. This is a long standing and the load was increased in 2007 and has now been increased to a 200kg load.


Despite this test and the demand for minimal wear on the skid blocks set into the plank, even stricter tests and definitions are now required to ensure teams are not beneficially allowing the device to move. Thus there will be a new a set of demands for the splitter from Monza onwards.

Firstly the construction of the splitter and plank are to be revised. The splitter or more specifically the stay the fixes the leading edge to the chassis must not consist of any articulated joints, such as springs bearings or any construction that would allow the stay to bend or buckle. Then the section of plank that sits beneath the splitter must be more than 1m long. It is thought that The shorter plank lengths are being used to allow the hinged mounting effect.

As evidenced by the unusual wear beneath Mark Webbers Red Bull in Valencia, there is wear at the very leading edge of the plank, this is to be expected, but a second patch of wear started where the plank splits.  It is likely that this area wears as the splitter deflects upwards forcing the leadign edge of the rear plank to hit the ground.  Of course this wear is not illegal in itself, as its only the depth at the inspection hole sin the plank, that are measured.  but this does gove some insight into how the floor is articulated.

With the split in the plank allowing the t-tray to bend upwards, a longer front section of plank will mean the plank extends behind the obvious place for the splitter to hinge, adding to the stiffness of the assembly. 

While the construction demands are tightened it will be the revised deflection test that teams will have the most work to counter. The new deflection tests not only places a greater load (2000n) on the centre of the leading edge of the splitter, but also an offset test,. Which places a lesser load at a point upto 10cm from the centre line of the splitter. The load this test applies to the splitter is an unusual request, possibly borne from the fact that wear is only measured on the centreline at leading edge of the plank. So teams might be allowing some twist in the splitter to for lower front ride heights, when the car is in a combination of pitch and roll. So while this twist will unduly wear the plank, it will not go detected as the wear is only measured within the 50mm dia hole at the centre front of the plank., As teams tend to run a single central stay at the leading edge of the splitter and have the leading edge of their splitter as very thin section. Most teams will need now to stiffen the leading edge of the splitter assembly, either via a thicker section or with additional stays. Any team making modifications has not necessarily been bending the rules, its just the new test is particularly severe and in a location not tested before.

However teams that have been flexing their splitter will certainly be handicapped by these revisions to the rules, although Monza is a low downforce track that will not particularly punish cars without flexing splitters. I don’t any team will fall foul of the test as they have rigs at their factories to recreate the FIA tests.

Renaults Splitter at the R30's Launch The Toro Rosso splitter at the STR5's launch Mercedes Splitter at the W01's launch

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Splitters Explained

Although low down in a dark area of the car and hidden behind bargeboards, the front splitter has been a critical part of the F1 car for many years. Known by many other terms, such as the shadow or legality plate, T-tray or bib, I’ll refer to this part as the splitter.

Since 1983 F1 cars have needed a flat floor in-between the front and rear wheels, then this floor needed to be stepped since 1995. In the late eighties when designers were slimming and raising the nose of the cars, there was a need to create a floor section under the front of the monocoque to meet the flat bottom rules. The most obvious first splitter was the Tyrrell 019 with its fully raised nose, since then the splitter has been more and more exposed as teams seek to raise and narrow the chassis cross section for aerodynamic benefit.

A splitters regulatory role has been to form the flat bottom of the car and from an attachment for the ‘plank’ running along the length of the flat floor. Thus the splitter must form the flat floor at reference plane level (the datum level where all bodywork measurements are, although the plank sits below this level). The splitter must also shadow the plan profile of the monocoque, such that the monocoque cannot be viewed from beneath the splitter.

However the need to have this bodywork forming the floor has been exploited and the splitter now forms aerodynamic and chassis functions of its own. As the term suggests the splitter separates the airflow passing under the raised nose between that which passes above and below the floor, equally its boats ‘bow’ shape above where it meets the monocoque also splits the airflow passing over the floor between left to right. Air then spills off the upper surface of the splitter and some of this will make its way under the floor and towards the splitter, thus the teams make use of this powerful flow to alter the pressure distribution across the underfloor to further improve airflow through the diffuser. allied to the fences, vortex generators and previously bargeboards, the splitter forms a critical role in the onset flow for the diffuser.

Brawns 2009 ballasted splitter

Being mounted low and far forward, the splitter also forms the location for ballast. Depending on the prevailing tyre and aerodynamic issues, teams can run as much as 50% of the cars weight on the front axle. with a rear engine car, the only way to do this is the ballast the front of the car and the splitter has been known to be made entirely from metal in order to maximise front end weight bias. Under the current aero and tyres rules, weight is somewhat more rearwards and the splitter is less heavily loaded with ballast

Deflection
In 2001 when the technical regulations demanded raised front wings (excluding the middle 50cm section) teams found the raised front ride height, cost downforce. Attempts were made to artificially lower the front wing when on track, both by flexing and by lowering front ride height. such is the geometry of the car, that the car cannot achieve enough rake to lower the front ride height without either excessive rear ride height or the splitter hitting the ground. A high rear ride height will cost rear downforce and stability, so the splitter needed to be moved out of the way. Teams found that deflecting the splitter upwards as it hits the track surface under braking allowed for lower ride heights. making the splitter far less stiff than it needs to be allowed the splitter to ride up without undue wear to the plank and skids which are measured in scrutineering for wear. Excessive wear to the skid block will bring penalties for the teams and drivers.

Hinged splitters allow lower front ride heights

However the FIA became wise to this practice and along with other deflection tests carried out on the he scrutineering rig, a test with push a hydraulic ram up from under the splitter was introduced. The car is bolted to the rig and the ram applies 200Kg of pressure to the front edge of the splitter, only 5mm of movement is allowed. this forced teams into running stiffer splitters and hence higher ride heights.

A hydraulic ram rises from the test rig to measure deflection to the floor

In order to regain the lower ride heights teams once again worked around the rules, by making the floors deflect at loads higher than the 200kg test. by hinging the splitter at its rear mounting and then making the front mounting a preloaded to 200kg. thus the floor will be be able to meet 200kg FIA test with little movement, but at loads over 200kg the front mounting will start to deflect and allow upwards movement for lower ride heights and more downforce. In Ferraris case this was a mounting with a small coil spring to provide the resistance to the 200kg load. McLaren had a pre-buckled stay, acting like a leaf spring between the floor and splitter. The justification for these very visible mechanical mounting was to avoid damage to the now very heavily ballasted splitter, when running over kerbs and bumps etc.

Ferraris 2006 preloaded sprung splitter support

One of the issues to fall out from the technical interchange between McLaren Mike Coughlan and Ferrari Nigel Stepney was Ferraris use of the splitter mounting. Knowing how Ferrari used the mounting allowed McLaren to ask the FIA technical delegate Charlie whiting for permission to use such as a system. this approach is a subtle workaround to a formal protest of another teams design, but ends up with the same result, either acceptance or a clarification banning the design. This issue arose at the start of 2007 and by the Spanish GP the teams were asked to remove deflecting splitter mounts, necessitating a redesign for most if not all teams. some people within the sport suggest Ferrari performance advantage from the previous few years was eroded by this rule change. since then teams run far stiffer splitter mountings and although several teams have been asked to revise their mountings since then by Charlie whiting, it is felt that there is little that can be done to deflect the splitter for performance benefit.

As you can see, FW Ride height is restricted by the splitter, unless the splitter deflects upwards

One of the explanations for the low wing ride height on the RB6 are suggested to be the splitter is allowing lower ride height by deflecting. Certainly trackside images suggest the Red Bull and the Ferrari are running significantly more rake in the set up at speed (i.e. nose down). Other teams suggest that this level of rake and low front wing ride height cannot be achieved with normal rear ride heights. But do not suggest how the car may be able to run that low. But the inference is that the splitter is in someway deflecting to allow this. I’ve not seen the detail of Red Bulls splitter mounting, but I doubt they are able to deflect the splitter without any obvious compliance in its mounting or undue wear to the skid blocks.

On a side note, it was Coughlans assertion that the Ferrari splitter of 2007 was also being sprung to create a mass damper effect, with mass dampers being banned the previous year.

Quote from Racecar-engineering.com “One of the defences used by McLaren was that Stepney, the former Ferrari employee, was ‘whistle blowing’ – something the court struggled to accept covered the whole affair, but it did certainly have an effect at the Australian Grand Prix. Ferrari won the race, but the FIA later outlawed the car’s floor. McLaren contended that the Ferrari that won was illegal, and a letter from Stepney to the FIA sent after the hearing revealed that it may well have been, as it was in effect a mass damper. Such devices were banned last season as they were controversially deemed to be a moveable aerodynamic device.
Stepney reveals in detail the exact workings of the floor that was used at the race: ‘The front floor is attached to the chassis via a mechanical hinge system at its most rearward point. The most forward support is a body with one compression spring and one tension spring inside which can be adjusted according to the amount of mass that is fitted to the front floor. There is also a skirt that seals the floor to the chassis, which is made out of rubber and Kevlar to help flexibility and reduce friction in the system.
‘If the system had been allowed it could have meant a huge cost of development for other teams in such areas as chassis and under trays etc to make way for the provision for storing the system and the variable quantity of mass. The possible long-term consequences of such a system would be quite substantial because the system is in a crude state of development.’
The system detailed by Stepney allowed the F2007 to ride kerbs harder due to the 14-15mm deflection at the leading edge of the floor, which means the Ferraris could straight line chicanes more than other chassis. Front plank wear would also be reduced, allowing the car to run lower at the front, giving an aerodynamic gain.
Stepney also explains the dynamic behaviour of the car, and the advantages the flexing floor gives: ‘From around 160-180km/h (100-112mph) the car is about 7-8mm lower at the leading edge of the floor, which multiplies up to nearly 19-20mm lower front wing height. The benefits in terms of ground effects and efficiency would be gained all around, with components like turning vanes and front wings at a reduced height relative to the ground.’ “

 

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Germany Tech Review now on Automoto365.com

My Technical review from Hockenheim is now on Automoto365.com.  With the update on McLarens Blown diffuser, Mercedes and Williams exciting ‘open-fronted’ exhaust blown diffusers, as well as updates from Virgin and Toro Rosso.

http://bit.ly/aviB74

or

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=7&seasonid=21&nextMode=ExclusiveNewsForm&news_id=41729

Aero elasticity – Red Bulls front wing

 

A very public exposure of the front wing flexing on the Red Bull was made during the German GP, the analysis by journalist Stephane Samson and photographer Darren Heath, showed the tips of the Red Bull front wing running far closer to the ground than their rivals. While some of these pictures can be explained partly by different ride heights, roll positions or attitude changes, some pictures show the Red Bull front wing in a drooped (anhedral) attitude. This has been backed up by on board footage, where by the roll hoop camera is fixed rigidly to the car and any movement of other sprung parts of the car should remain immobile in relation to the camera. Yet still the RB6 has routinely exhibited excessive movement through out the car speed range.

Aero Elasticity
Since the nineties F1 teams have been exploiting a phenomenon called “aero elasticity”, this is where the bodywork of the car, mainly the wings, flex to alter their aerodynamic characteristics. At first this was largely created by the entire rear wing assembly bending it backwards, then more specific parts of the rear wing and as exposed this season, the front wing of the Red Bull has been visibly flexing.

This flexibility can be for three different benefits, either reduced drag, improved balance or greater downforce. With a rear wing limiting top speed, most attention has been paid to reducing its drag. As mentioned this was first tackled by the top rear wing and endplates being angled backwards by the beam wing twisting. A few pre-season failures leading to big accidents saw the FIA introduce the first bodywork flexibility rules. In order to enforce the rules, the FIA designed the first deflection test, a rig pulls the wing backwards by the endplates and the deflection was measured. While this test stopped this practice, it also set a standard to which the cars had to meet in order to be deemed legal. Thus if the car passed the scrutineers deflection test, it was approved to race. However if the car could flex its wings and still meet the test, then they had an advantage that couldn’t be immediately penalised.
Soon teams sought to reduce the angle of attack of the rear wing via flexing the flap or main plane. Then as the FIA introduced additional deflection tests to circumvent these workarounds, the teams flexed the wings to reduce the slot gap and stall the rear wing (Much like a passive F-duct), again deflection tests and latterly the slot gap separator effectively stopped this practice.

Front wing flex

 
Exploiting aero-elasticity with the front wing has not been to reduce drag for greater straight-line speed, as the front wing produces very little drag. At the end of the nineties teams were using front wings that drooped into an anhedral shape (i.e the tips drooping downwards creating an inverted “V” shape). This placed the wing and its endplates closer to the ground, both of which gained more downforce. Firstly the wing was closer to the ground which increased the ground effect. Up to a point the lower a wing is to the ground the more downforce it generates. Then the endplates role in sealing the high pressure above the wing from the low pressure below it, is improved if the endplate can run closer to the ground. Effectively make it act like an Eighties wing-cars skirt. To prevent this the FIA produced another deflection test; a 50kg (500n) load is applied to the wings endplate, should not produce more than 10mm of movement. Again this had largely stopped the practice of excessive deflection for front wings.

However there were still benefits to be had from flexing the front wing flap that was not affected by this test. Instead the wing has been flexed to main a stable centre of pressures position, flexing the flap downward at speed to reduce the wings angle of attack reduced downforce and moves the centre of pressure backwards, reducing the cars tendency to be oversteery at high speed. There is now a deflection tests to prevent this practice.

Red Bulls RB6 front wing

At some races last year and evident through out this year is the front wing of the Red Bull RB6 flexing at speed. Visible from the on board camera above the drivers head, the front wing tips can be seen to slowly run closer to the ground as the car accelerates. As this is a low frequency movement, the effect can be seen in reverse as the cars brakes from high speed. The wings endplates springing up as the car rapidly loses speed and the aero load applied to the wing diminishes. This was clearly visible from the early season races and as early as the Chinese GP I emailed the FIA about this practice and whether it was deemed legal. They reiterated the standard 500n – 10mm deflection test and suggested the car was legal, not directly countering the point that the wing is seen flexing. While most teams wings will flex at high speed, whereby some movement is often seen as the car brakes from high speed. The amount of movement and the low speed at which it starts to occur are startling with the Red Bull wing. The point made by the FIA to me back in April and again after the German GP in late July was that the car met the deflection test, thus was legal to race.

This flex was seen back in China 2010, not simply Germany

Front wing Load cases
An F1 car makes its own weight in downforce at just 70mph, that’s ~600kg of load on the car, half of this load is from the wings and half from the diffuser, thus the wings create some 300Kg of load at this speed. With the cars centre of pressure being some where near 45% forward biased, this means the front wing is creating something like 140Kg of load, split between the left and right wing each wing is producing 70Kg of load at just 70Mph. this is the speed of the slowest turn at the Hungaroring this weekend and only slightly faster than the hairpin at Monaco! Thus the FIA limit of 50kg is vastly under specified for the actual load an F1 car sees at even the slowest circuits. Its not surprising a team can created a wing to beat the 50Kg-10mm deflection test and yet achieve far greater deflections, suggested to be as much as 25mm, at much faster corners.

How’s this done – is it legal?
An F1 front wing is a complex moulding of carbon fibre bonded to metal sections. Although the flaps and endplate are detachable, from a structural point of view a front wing is a single piece. Mounted at its centre section by pylons affixed under the nose cone, itself stoutly fastened to the front of the chassis. In the eyes of the rules and with the exception of the driver adjustable front flap, the front wing should meet the regulation 3.16 regarding aerodynamic influence:

-must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom);

- must remain immobile in relation to the sprung part of the car.

Therefore the entire assembly can not be allowed to move in relation to the rest of the car. However no car can be 100% rigid and F1 cars are subjected to huge aerodynamic loads, hence the reason for the FIA to set the deflection test. If the wing can meet the test and still deflect above the test load, then the FIA deem it legal and the car can race. This could be achieved by accident or by design. Its possible that the carbon fibre lay up creating the wing will continue to deflect in a linear way all the way from zero load to 50kg and then for loads of 50kg upwards. It’s reasonable to assume most teams wing respond this way. However it’s possible to alter the layup of the carbon fibre or add some from of mechanical system (i.e. hinges or springs) to allow a non-linear repsonse to create the 10mm of movement at a 50Kg load, then create greater deflections above 50Kg. Thus the engineers could create wing that meets the deflection test, but would then deflect down to a desired ride height at a specified maximum speed.

While this is against the “spirit of the rules” which prohibit flexible bodywork they meet the test as defined by the FIA for flexible bodywork, thus the Red Bull and the Ferrari front wings are free to race in the eyes of the FIA.

I have again emailed the FIA to ask about additional deflection tests and have yet to receive a response.