Renault: Front wing endplate design

Through out 2010 and in the opening races of 2011, Renault have been extremely productive in producing front wing updates. With revisions at the rate of one per race so far in 2011, no other teams has produced the number of iterations that Renault have managed to roll out. In China Renault produced a revised endplate, this was subsequently revised for Turkey along with new wing mounting pylons. For the Spanish GP, there will be yet more updates in this area.

Renaults front wing has been the leader of the current evolution of endplate-less front wings. where as teams used to have a clear distinction between the front wing elements and the vertical endplate, now teams curl down the tips of the wings to form the lower part of the endplate, then add vanes for both bodywork legality and to direct airflow around the front tyre. then the team add small cascade winglets and the entire picture of how the front wing is working becomes complicated. If we remove the vanes and cascade winglet to view them individually, this situation becomes a little clearer.

Another Renault feature has been to split the footplate, last year the footplate sloped down and the tubular-like rim was fitted to the meet the bodywork legality dimensions. Now the team simply slot the footplate to allow airflow to pass low around the front tyres.

Renault also now exploit the camera position by placing the two mandatory camera pods behind the neutral Drawing7 section of front wing. positioned here the camera pods offset the lift created by the neutral centre section of wing. Also interesting to note is the front bulkhead shape of the R31, the “V” nose is unusually rounded at the bottom, as can be seen by looking at the lower rear face of the nose cone.

In Turkey the front wing gains a small flap added the smallest outboard vertical vane. As well as faired extensions to the pylons that mount the wing to the nose. similar to Ferrari sinterpretation of the mounting pylons this, although Renault did extended the pylons to form s vanes, albeit in a slightly different manner in 2009-2010.

Toro Rosso: Radiator layout

Toro Rosso went aggressive with the design of the STR-06, by adopting a double floor sidepod design. Although the team refer to it as a deep undercut sidepod, the effect is very much aimed at removing the blockage of the sidepods from the flow passing low along the floor towards the diffuser. We have previously described the external design of the sidepod (http://scarbsf1.wordpress.com/category/toro-rosso-str06/). We can now see the radiator layout required to make this packaging work. Surprisingly the radiator layout is quite conventional with good sized coolers fitted within the smaller sidepod envelope.

Firstly we can see the sidepod is raised above the floor, the yellow areas is free for airflow to pass under the sidepod shape and reach the diffuser. Ex-BMW Sauber head of Aero Willem Toet pointed out that this design creates a large area of exposed floor surface for the air to pass over, which might create problems with increasing boundary layer and hence drag. Potentially the ducted exhaust solution speeds up the slowing airflow over the latter part of the floor before reaching the diffuser.

Within the sidepod the radiators are made up of several cores, each serving different cooling needs for engine oil, engine water and KERS water cooling. Hot water exits the engine from the cylinder heads and passes to the radiator (red) and then the core cools the liquid before passing back to the water pump and lower front of the engine. It’s interesting to note the water pipes exit the engine as a single hose, but spit to feed the radiator core in two places to ensure an even distribution of coolant across the relatively large cooler.

A small water cooler also serves to cool the battery pack for the KERS.

Copyright: Liubomir Asenov/ClubS1

In this right-hand sidepod we can see the radiator follow a slightly different construction as the oil cooler is also place din this sidepod.

FIA: Ban on Aggressive off-throttle Engine maps

 

Teams have been adopting exhaust blown diffusers (EBD) since last year and in 2011 every team has exploited the exhaust to some extent to help drive airflow through the diffuser. As I have explained in previous posts on the subject (http://scarbsf1.wordpress.com/category/exhaust-driven-diffuser/), the problem with EBDs is that they create downforce dependant on throttle position, so as the driver lifts off the throttle pedal going into a turn, the exhaust flow slows down and reduced the downforce effect, just at the point the driver needs it for cornering.

If a team want to really exploit the benefits of an EBD then they need to resolve this off-throttle problem. Last year Red Bull exploited a different mapping of the engine when off throttle (see http://scarbsf1.wordpress.com/2010/07/10/red-bull-map-q-the-secret-to-the-teams-q3-pace/ ). By retarding the ignition when the driver lifts off, the fuel is no longer burnt inside a closed combustion chamber, but instead the fuel and air burn in the exhaust pipe, the expandign gasses blow out of the exhaust exit as though the engine is running . This creates a more constant flow of exhaust gasses between on and off throttle. The problem here is that the mapping uses more fuel and creates excessive heat in the exhaust pipe and at the exhaust valve. Renault reported that both Red Bull and Renault used 10% more fuel in Melbourne compared to last year, most likely due to these off-throttle mappings.

With these off throttle mappings the fuel burns in the exhaust pipe, not the cylinder

 

As the engine suppliers have become increasingly comfortable with the heating effect of these off throttle mappings, teams have been able to use more of this effect in the race. One of Red Bulls advantages this year according to McLaren is their use of aggressive engine maps for downforce. At the Turkish GP several people pointed out the engine note on the overrun on Alonso’s Ferrari during FP2. Teams have clearly started to drive the engine quite hard when off throttle, to keep the diffuser fed with a constant exhaust flow.

Now the FIA have stepped in to limit this effect. Although initially scheduled to be in effect from this weekends Spanish GP the change will now take effect after Canada. This clarification is based on Charlie Whitings changing opinion of how these mappings are used. At first some mapping was allowed, but these increasingly aggressive and fuel hungry mappings are changing the engines primary purpose. Effectively when off throttle the engine is being used purely to drive the aerodynamics, this contradicts the regulation on movable aerodynamic devices. Although this is a vague interpretation it can be justified.

What is now required is that the engines throttles (at the inlet manifold) must be closed to 10% of their maximum opening when the driver lifts off the throttle pedal. Unlike in most road cars, in an F1 car the engines throttles are not under the direct control of the driver via the pedal. The throttle pedal is instead the drivers method to request powertorque, the cars SECU then controls the level of throttle required to meet the drivers request. So as the driver lifts off the throttle pedal, he is no longer requesting powertorque and therefore the throttles should close. what happens with these EBD mappings is that the throttles remain open, Fuel continues to flow then the delayed spark from the plugs sends the burning charge down the exhaust pipe.

Now with the throttle closed to 10%, the amount of fuel that can be burnt will be limited and thus the blown effect will be reduced. so drivers see will a bigger variation in downforce as they modulate the throttle pedal, making the car less predictable to drive.

Blowing the exhaust under the 5cm of outer floor (yellow) will be most penalised by the ban

 

All teams will be affected to some extent, however the more aggressive that teams have been with the exhaust position relative to the floor, then the greater they will be affected. From the start of the season Red Bull, Ferrari and McLaren have blown the exhaust at the outer 5cm of diffuser. this area is allowed to to be open and bow the exhaust gas under the diffuser for greater downforce. these designs will be most greatly affected by the clarification. Renaults Front Exit exhaust is also likely to be a victim of the change. Many teams have been developing Red Bull Style outer-5cm EBDs, such as: Williams, Lotus, Virgin, Sauber, While Mercedes are rumoured to be adopting a front exit exhaust. These may to need be shelved after Canada, in order to employ a less aggressive EBD.

Red Bull: Front brake ducts and wheel design


Since the start of the season red Bull have been running these complex brakes ducts on the RB7. The design varies between the front and rear, where as the front bake ducts used to be the more complex, the Turkish update to the rear ducts probably balanced their complexity.

At the front, the heated flow exiting the brake disc passes through the drum shaped duct via 9 angled vanes. These help direct the flow out of the wheel. Additionally there is a secondary outlet made into the leading face of the drum.

Feeding the disc is a solution also employed by Renault, where the main inlet scoop is allied to another inlet on the inside of the protruding vane.  This creates a large amount of inlet area, but only requires a small scoop sitting out on the airflow inbetween the wheel and chassis, which should create less drag.

Red Bull started a trend in 2009 with wheel with a much shallower offset between the spokes and the outer rim of the wheel. This was partly to bring the spokes closer to the airflow to provide some aerodynamic benefit. Also the change created more space inside the wheel for the upright and potentially longer wishbones.

The current wheel design features 11 solid spokes, which have a slight “H” section to them. As the side faces of each spoke are machined with a small pocket to reduce weight. Its visible that the outer face of each spoke has sharp right-angled edge. However less visible in the inside face of each wheel spoke, features a generous fillet radius to help the streamline the spoke to improve airflow out of the wheel.

New "Vaned" wheel for Spain via @slitz (http://twitter.com/#!/slitz)

It is expected that Red Bull will feature more complex wheel design this weekend. This could either be a revised spoke design to work in conjunction with the brake duct vanes, or an even shallower offset to move the spokes closer the wheel rim or a switch to wheel with radial vane, as used by Ferrari and McLaren.

As soon as the wheels are uncovered, this post will be updated.

Red Bull – Pull rod suspension detailed

Via Motorsport Magazin

From these images we can finally see some detail of the Red bull gearbox. Firstly the construction is carbon Fibre, which the team switched to mid way through 2009, in order to save weight over the old aluminium case.

Top wishbone location - via Motorsport Magazin

Then we can note the geometry of the wishbones, Red Bull followed high mounted wishbones since the RB5, the rear top wishbone (RTWB) being very high and near horizontal, being mounted to the ridge along to the top of the gearbox.

Differential - via Motorsport Magazin

Equally Red Bull have gone for a low differential, but the total effect is a very tall and bulky gearbox, albeit one that fits into the natural space created as the car tapers to the rear. But compared to Williams gearbox its clear to see where better airflow can be created at the tail of the car.

Pull Rod - via Motorsport Magazin

It’s rare to find pictures of the Red bull pull rod suspension. The low mounted mechanical parts normally covered by body panels and heat shielding. But here we can quite clearly see the pull rod leading down to the rocker. The pull rod is split to allow easy ride height changes by adding shims into the split and also allows the pull rod to be permanently mounted to the bearings on the rocker. When the rear wishbones are removed this lower part of the pullrod will remain with the gearbox. In turn the rocker operates the compliant elements of the rear suspension, the springs, dampers and heave elements.

Damper - Via Motorsport Magazin

The damper is clearly visible being mounted alongside the flanks of the gearbox case. The red anodized body and labels making it easy to spot. Note the rocker has a longer lever to operate the damper in comparison to the lever that the pull rod mounts to. This is to increase damper travel compared to wheel travel for greater wheel control.

rocker or Bell Crank - via Motorsport Magazin

Its not clear if the rocker works on a torsion bar t provide the rear springing, its believed Red Bull went away from torsion bars and individual wheel springs in 2009. Instead using the heave spring allied to the antiroll bar for a springless rear set up (read more at http://scarbsf1.wordpress.com/2010/12/03/spring-less-rear-suspension-a-quiet-revolution/). If a torsion bar is used it will need to run near vertically along the axis of the rocker.

Rocker to operate the Heave spring - via Motosport magazin

Not entirely visible is the heave control set up, this will consist of a Heave spring, damper andor bump rubbers, plus an inerter (not strictly for heave control but mounted in the same location). These run across the front of the gearbox, being mounted just above the clutch. We can see the splined end of the anti roll bar; the bar will have levers reaching forward to drop links that will provide the rear roll control.

Antiroll Bar location - via Motorsport Magazin

More on Pull Rods http://scarbsf1.wordpress.com/2010/10/10/red-bull-pull-rod-suspension-what-is-looks-like-how-it-benefits-aerodynamics/

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Red Bull – KERS installation detailed

via Motorsport Magazin

Having run KERS for Friday only in Melbourne, RBR will probably run the KERS system for the full weekend in Sepang. As RBR were not seen to use KERS on their qualifying laps, although they were unknown to be equipped with Renaults KERS raised rumours of a start only KERS. While a start only KERS is technically legal and has some technical advantages, it’s not thought such a system is planned for any team.
From images seen this in the team’s garage this morning we can see the KERS set up quite clearly. The actual set up is quite different to the image provided by Red bull in their Launch press pack. Which shows a far more conventional layout?

KERS control unit - Via Autosport.com

On the right hand side of the car, we can see a silver box with FIA anti-tamper seals; this is the KERS control unit (KCU). This controls the power exchange between the motor generator and the battery pack. The thick red cables carry the current in between these other devices. Running very hot from the current passing through it, the KCU will have a cool air feed from the sidepod ducting. Although not certain, the small radiator at the bottom of the other coolers is probably to cool the battery pack.

Possibly the KERS water cooling radiator - via Autosport.com

From the other side we can see the Battery pack, unusually this is mounted to the side of the gearbox. It is the rounded carbon fibre item, with the yellow warning sticker.

KERS Battery Pack - via Autosport.com

The other three KERS suppliers (Mercedes, Ferrari and Williams) all place this item beneath the fuel tank for better weight distribution and crash safety. Although McLaren did place theirs low down in the front of the sidepod in 2009. With the more rear biased mandatory weight distribution rule, this more rearwards location is not a handicap. It frees up fuel capacity and sits inside a dead area of space within the sidepod. You can see the same thick red cable emerging from the battery pack. Inside the carbon case will be an array of small lithium-Ion cells (Li-ion). These will run at high temperatures as the cells charge and discharge, as explained they will be cooled a dedicated water radiator and pump.

More on KERS: http://scarbsf1.wordpress.com/2010/10/20/kers-anatomy/

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The Flying Lap

 

If you havent already started to watch this show, I suggest you really should. Theflyinglap.com, is a webcast and audio download going out every Wednesday at 6pm UK time. Peter Windsor runs this show from a studio in London. He’s had guests as varied as Frank Williams to John Surtees, Willem Toet and Sergio Rinland on the technical side. The show is an hour of live F1 chat with journalist and people within F1, often with aftershow chat continuing for upto an hour after the live show. the show is then available from smibs.tv, youtube and available as a free I-tunes download.

I dont know any other source for such a long and in depth insight into F1, that goes out every week. I’ve made three appearances talking about the new rules, testing and post race analysis. I’ve linked to the latest one below.

http://www.youtube.com/watch?v=WA4SHUbZZig

Renault – Front Exit Exhaust Details

Copyright Sutton Images via Formula1.com

Although we almost didn’t believe it when the rumours emerged at the launch of the Renault R31, The car does indeed have exhausts that exit at the front of the sidepods. We (@f1fanatic.co.uk and I) managed to see, understand and get the first pictures of the unique set up (http://scarbsf1.wordpress.com/2011/02/01/renault-r31-front-exit-exhausts-fee-explained/). Now the car can be seen stripped in the pit garage, we can see exactly how the Renault packages the exhaust.

The exhaust system routes the four pipes into a collector which then continues to point forwards and direct the secondary pipe low underneath the radiator to the front of the sidepods. As the exhaust routes gasses at up to 1000-degrees C, it needs insulating to protect the other equipment housed in the sidepods. Renault appear to have fitted an insulated jacket around the main length of pipe in the sidepods. What is clear from the set up is that Renault had to raise the radiators to allow the pipe to ass underneath. The R31 has unusually large sidepod inlets and this might to cope with the ducting of the cooling airflow to the laid down radiator.

Copyright: Andrew Robertson (@JarZ)

From these pictures via Andrew Robertson (@Jarz) we can see the front detail around the sidepods. Although the exhaust outlets are not seen here, the problem of the final routing is apparent. Teams need to fit beams to the side of the monocoque for side impact protection. Known as Side Impact Tubes (SITs) there are two pairs to share the load, with one upper pair and a lower pair. As these SITs are heavy, the majority of the work is down by the lower pair, to keep the weight low in the car. Correspondingly the lower SITs are larger and the exhaust needs to pass over these and down to exit sideways.

Copyright: Andrew Robertson (@JarZ)

Renault has packaged these lower SITs into a narrow front and wider rear Tube. The exhaust will angle down along the front tube to blow still pointing downwards across the lower leading edge of the floor. We can see the metallic heat protection on the SITs.

Copyright: Andrew Robertson (@JarZ)

More info on Front Exit Exhausts and how they work – http://scarbsf1.wordpress.com/2011/03/22/trends-2011-exhausts-and-diffusers/

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Williams – Lowline gearbox in detail

Copyright Andrew Robertson (@JarZ)

Having been obvious at its launch the Williams FW33 has a radical shrunken gearbox case. Now we can see how the case is actually configured, which is close to the diagram I posted back in February (http://scarbsf1.wordpress.com/2011/02/10/williams-fw33-lowline-gearbox/). As I explained Williams sought to remove as much blockage ahead of the beam wing as possible, to do this they lowered the top of the gearbox, switched to a Pull-Rod set up and repositioned the differential much lower. The revised layout has lead to a very neat gearcase.

Nico / Slideways @ Autosport.com

Copyright Andrew Robertson (@JarZ)

To get a reference point for what we see in this picture, it’s the lower wishbone that’s fitted. This is usually mounted halfway down the gearcase and the top wishbone mounts above it. So what we are seeing is the casing dropping downwards from its front face to create a low flat top. It’s this front face that also gives an idea of how high a conventional gearcase is. So clearly Williams have lowered the case dramatically (see below).

Copyright: Andrew Robertson (@JarZ)

Copyright: Andrew Robertson (@JarZ)

Equally the differential (the diff’ circled above) is very low too, normally its several centimeters above the lower wishbone, now the diff’ is below the wishbone. This is why when we see the car from behind; we can see the driveshaft’s angle upwards from the gearbox at an extreme angle. Above the diff’ is the bolt on wing mount, as explained in my previous article, this metal structure supports both the rear wing and the top wishbone. One curiosity of the diff’ and wing mount set up is how the diff’ is removed. Normally the gearcase is split to allow the differential to be removed from the back of the case. Perhaps with the new Williams set up, the case has a cover over the left hand side of the differential and the diff’ is removed sideways. This set up would create a slightly stiffer case, critical for its complex waisted shape.

Copyright: Andrew Robertson (@JarZ)

Not seen in this picture is the top wishbone, it mounts to the top of the bolt-on metal pylon and also to the pick up on the front of the casing (circled above)

Copyright: Andrew Robertson (@JarZ)

Williams have also switched to a pullrod suspension, this places the rocker linkage and the dampers low down at the front of the gearbox. The dampers heave spring and inerter have to pass horizontally across the front of the gearbox; they enter the gear case via the aperture seen at its lower front side.

More info on Pull Rod Suspension
http://scarbsf1.wordpress.com/2010/10/10/red-bull-pull-rod-suspension-what-is-looks-like-how-it-benefits-aerodynamics/

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McLaren rear end: Exhaust, cooling and suspension

 

A ScarbsF1 follower in the Melbourne pit lane sent me these exclusive pics. We can see the McLaren stripped in the garage. There’s a huge amount of detail to take in, The key details are the missing exhaust heat shielding, cooling ducts and suspension detail.

We can see the exhaust system is missing in the picture. However there’s a lot of grey heat shielding around the floor giving us some clue to where the flow is going. Notably at the side of the engine where the main exhausts will sit and beyond exit to the sidepod. I can also see heat shielding above the starter motor hole, which is a rounded profile further suggesting this will be subject to fast exhaust gas flow. There’s a curious bulge in the tail of the coke bottle shape. This would be next to the exhaust collector and unlikely to be a good place for sensors, so it’s a mystery why this shape is there.  So we can see potentially an exhaust route blowing out of the back of the sidepods, some of this flow passing under the gearbox to the starter motor hole.  This seems innocuous enough, as long as the gas finds its own way to these areas.  Continued rumours around the pitlane suggest bodywork is used to duct flow to these areas, which would be a contraversial solution.  Only when the car is fully built and scrutineered will we fully know what the solution is.

As already explained in this blog (http://scarbsf1.wordpress.com/2011/02/16/mclaren-roll-hoop-and-cooling-arrangement/) the roll hoop fulfils several function for engine air feed and cooling. We can see the main airbox, beneath it the KERS cooler and its exit duct wrapping around the airbox. At the rear of the airbox is the gearbox oil cooler. The oval exit duct for this cooler isn’t fitted in this picture.

Lastly the pullrod suspension can be seen, the rocker and some of the springdamping set up is down low on the gearbox. A small detail is the shaft and rocker merging vertically from the gearbox, (beneath the silver pipe with blue connector). This might either be the heave damper or inerter, placed higher up for better access, or it might be the pre-load adjuster for the torsion bar (if torsion bars are fitted).

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