Book Review: Haynes Red Bull Racing F1 Car

When Red Bull Racing launched their new car for 2011, the event was marked by a very special press pack. The pack was formatted in the style of the well-known Haynes maintenance manuals (PDF). This in itself this was a great book, but almost unnoticed within its pages was the intended publishing of a complete Haynes style workshop manual on the RB6 car.
Now some six months later the Haynes Red Bull Racing F1 Car Owners Workshop Manual (RB6 2010) has been published. As its rare a Technical F1 book is published, not least one with insight into such a current car, I’ve decided to review the book in detail.

Summary
At 180 pages long the book has enough space to cover quite a wide range of topics and it does so. Starting with a background to the team, moving on to the cars technology, to overviews of its design and operation. With its familiar graphical style and hardback format it certainly gives the feel of a proper workshop manual. However this is somewhat skin deep and the pages within, soon revert to a more typical book on F1, although some flashes of the Haynes style do remain.

Steve Rendle is credited as the writer of the book and Red Bull Racing themselves have allowed close up photography of the car and its parts, as well as providing a lot of CAD images.
But clearly a lot of editing has been carried out by Red Bull Racing and the book falls short of its presentation as a manual for the RB6. Despite its confusing title, the book is probably better described as a summary of contemporary F1 technology from the past 3 years.
As the last in depth technical F1 book was the heavy weight title from Peter Wright showcasing Ferraris F1 technology from 2000, this remains a useful source of recent F1 technology.
This places the books target audience, somewhere between the complete novice and those already of a more technical mindset.

Anatomy

With forewords by Christian Horner and Adrian Newey, the opening 21 pages are a background to the team and detail of the 2010 season that brought RBR the championships. Then starts the core 100 page chapter on the cars anatomy, which opens with a pseudo cutaway of the car showing a CAD rendering of its internals.

Firstly the monocoques design and manufacture is covered, with images of the tubs moulds being laid up and CAD images of the RB4 (2008) chassis and its fuel tank location. Although little is made of the fuel tank design.
Moving on to aerodynamics, the text takes a simplistic approach to explaining aero, but there is an interesting illustration of the cars downforce distribution front to rear. This does highlight the downforce created by the wings and diffuser, but also the kick in downforce at the leading edge of the floor, but this is not adequately explained in the text. Mention is made of the front wing and the flexing that RBR deny, this is explained with a simple illustration showing the deflection test. The driver adjustable front flap, which was legal during 2009-2010 seasons, is explained, in particular that the wing was hydraulically actuated. When I understood that in 2009, only Toyota used a hydraulic mechanism over the electric motor system used by all other teams. In trying to explain the nose cone, the text and an illustration show a high nose and low nose configuration, but does not remark why one is beneficial over the other.

This section also covers very brief summaries of bargeboards, sidepods and the floor. Some nice close up photos of these parts included, but again with little explanation. An illustration at this point highlights the other FIA deflection test altered in 2010, which was aimed at Red Bulls alleged flexing T-Tray splitter. In this section the text cites Ferraris sprung floor of 2007, but not the allegation that RBR’s was flexing in 2010. A further simple graphic illustrates the venturi effect of the floor and diffuser, and then the text goes into simple explanations of both the double diffuser and the exhaust blown diffuser.
Having been one of the technical innovations of 2010 and since banned, the book is able to cover the F-Duct is some detail. A complete CAD render of the ducting is provided on page 53; this shows an additional inlet to the drivers control duct that was never visible on the car. This extra duct served the same function as the nose mounted scoop on the McLaren that introduced the F-Duct to F1.
Thus with aerodynamics covered in some 23 pages, the text moves onto suspension and the expectation of detail on the RB5-6’s trademark pullrod rear suspension. After a summary of the purpose of an F1 cars suspension, Pages 58-59 have some fantastic CAD renderings of front suspension, uprights and hub layouts. However the rear suspension rendering stops short at the pull rod and no rocker, spring, damper layouts are detailed. Hardly a secret item, so lacking this detail is let down for a book announced as an RB6 workshop manual. A lesser point, but also highlighting the censorship of some fairly key technical designs, was the lack of any reference to Inerters (Inertia or J-Dampers), The suspension rendering simply pointing to the inerter and calls it the ‘heave spring’, while naming the actual heave spring damper as simply another ‘damper’. Inerters have been in F1 since 2006, predating Renault’s mass damper. Their design and purpose is well documented and shouldn’t be considered something that needs censoring. It’s also this section that fails to showcase the RB5-6 gearbox case. Instead using a pushrod suspended RB4 (2008) gearbox, albeit one made in carbon fibre.
The steering column, rack and track rods are similarly illustrated with CAD images. This usefully shows the articulation in the column, but little of the hydraulic power assistance mechanism. Page 67 starts the section on brakes, again fantastic CAD images supply the visual reference for the upright, brake caliper and brake duct design. As well as a schematic of the brake pedal, master cylinder and brake line layout of the entire car. A nod to more typical Haynes manuals shows the removal of the brake caliper and measure of the Carbon disc\pad. A further CAD image shows the brake bias arrangement with both the pivot at the pedal and the ratchet control in the cockpit for the driver to alter bias.
Although not a RBR component the Renault engine is covered in the next Chapter. An overview of the complex engine rules regarding the design and the specification freeze kicks off this section and cites the tolerances and compression ratio for a typical F1 engine. Pneumatic valves, for along time an F1-only technology are explained, but even I failed to understand the schematic illustrating these on page 77. Also covered in the engine section is some more detail on the fuel, oil and cooling systems. With useful specifics, like capacity of the oil system at 4 litres and water coolant at 8 litres. Again some nice CAD images illustrate the radiators within the sidepod. Many sections have a yellow highlighted feature column; this sections feature is on the engine start up procedure, one of the mundane, but rarely talked about processes around an F1 car (other features are on the shark fin and brake wear). As KERS wasn’t used up until 2011, this topic is skipped through with a just a short explanation of the system.

Moving rearward to the transmission system, the old RB4 gearbox makes a reappearance. Again this disappoints, as some quite common F1 technology does not get covered. Page88 shows some close up photos of a gear cluster, but this is not a seamless shift gearbox. In fact seamless shift isn’t mentioned, even though it made its RBR debut in 2008, the year of the gearbox showcased in the book. I know many will highlight that this might be a secret technology. But most teams sport a dual gear selector barrel, each selector looking after alternate gears to provide the rapid shift required to be competitive in F1. So I think this is another technology that could be explained but hasn’t been.
Tyres, Wheel and Wheel nuts get a short section, before the text moves onto electronics. A large part of the electronic system on a current F1 car is now standardised by the Single ECU (SECU) and the peripherals that are designed to support it. So this section is unusually detailed in pointing out the hardware and where it’s fitted to the car. From the tiny battery to the critical SECU itself. Other electronic systems are briefly described from the Radio, drivers drink system to the rain light.
Of critical importance to the modern F1 car are hydraulics, which are detailed on p105. As with the other sections, CAD images and some photos of the items themselves explain the hydraulic system, although there isn’t a complete overview of how it all fits together.
Rounding off the anatomy chapter is the section of safety items and the cockpit. The steering wheel and pedals are well illustrated with CAD drawings and keys to the buttons on the wheel itself and on the switch panel inside the cockpit.

While I have pointed that the hardware shown in the anatomy chapter isn’t necessarily of the RB6, what is on show is obviously genuine and recent RBR. So for those not so familiar with the cars constituent parts, there isn’t a better source of this available in print today. Even web resources will fail to have such a comprehensive breakdown of an F1 car.

The Designers view

Moving away from the Haynes format of a workshop manual, the book then moves into a chapter on the cars design, with comments from Adrian Newey. It details the Design Team structure and some of the key individuals are listed. The text then covers the key design parameters; centre of the gravity and the centre of pressure (downforce). Plus the design solutions used to understand them; CFD, Wind Tunnels and other simulation techniques. Each being briefly covered, before similar short sections on testing and development close this chapter.
Although the text makes reference to creating ‘the package’, something Newey excels at. This section doesn’t provide the insight into the overall design philosophy, which one might have hoped for.

The Race Engineers view
Where as the Designers view chapter was limited, the race Engineers section was a little more insightful into the rarely talked about discipline of getting the car to perform on track. The process of setting up the car is covered; from the understanding of the data, to the set up variables that the race engineer can tune; suspension, aero, ballast, gearing brakes and even engine. Usefully the grand prix weekend is broken down onto the key events from scrutineering, to running the car and the post race debrief. Feature columns in this chapter include; Vettels pre race preparation and the countdown to the race start.

The Drivers view
Ending the book is an interview style chapter on the driver’s time in the car, mainly the driver’s perspective from within the cockpit when driving the car on the limit and the mindset for a qualifying lap. A simplistic telemetry trace of a lap around Silverstone is illustrated, although there is little written to explain the traces (brakes, speed and gear), this is accompanied by Mark Webbers breakdown of a lap around the new Silverstone circuit.

In conclusion
When I first got this book, I was constantly asked if it was worth the purchase or if I’d recommend it. If my review is critical at points, it’s mainly because some technology that could have been covered wasn’t. Or, that the content falls short of the books title suggesting it was a manual for the RB6.
Those points aside, I have learnt things from this book. Like details of the F-duct system, the Front Flap Adjuster and a wealth of smaller facts. There isn’t a better book on the contemporary F1 car. In particular the CAD drawings and close-up photos, just simply aren’t in the public domain. From the pictures we got over the race weekends, we never get to see half the hardware and design work that’s pictured in this book. So I’ll keep this book on hand for reference for several seasons to come.

Overall I’d recommend this book to anyone with a technical interest in F1.

Many thanks to Haynes Publishing who have allowed me to use their Images and PDFs to illustrate this article

This book is available from Haynes

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…..

Spring-Less Rear Suspension – A Quiet Revolution

In the latter part of the year suggestions were that teams were discarding the rear side springs to allow very soft rear ends.   This has proved to be the case, in the past few years teams have been removing their rear torsion bars to gain greater control of suspension set up.  This revolution has been quietly spreading as many teams have gone this route.

An early sign springs were being removed was  the I-Racing game, which accurately modeled the FW31 with the Williams teams assistance, the game provided no scope for rear springs.   Equally comments made by Anthony Davidson over the Abu Dhabi Grand Prix weekend suggested that McLaren’s extreme stiff front\soft rear was due to this set up. Leading to Buttons problems locking up the inside wheel under braking. Closer investigation with technical people close to the sport prove this to be case and the practice is widespread amongst several teams, already McLaren and Williams are highlighted as adopting this practice, but Toyota and red bull are sporting this set up, by virtue of their gearbox supply this suggests that force India and Toro Rosso have the option too. Although this seems to be a relevantly recent practice as most teams first designed this into the 2009 cars, albeit it may have been tested or raced before then.

Suspension on F1 cars has the joint purpose to control the cars attitude both for aerodynamics and tyre dynamics. These often contradictory requirements have lead to compromises, largely against tyre performance and more to the benefit of aero control. Aerodynamicists want the car to run flat (or raked) with little change in roll or ride height. For mechanical grip the car needs softer attitude control. This has lead F1 cars to run quite stiff front ends and softer rear ends, both in roll and heave. A soft rear ARB creates more mechanical grip, which then in turns needs to be controlled by a stiff front anti roll bar. For aerodynamics reasons the front wing and splitter like to be flat to the track surface to gain most downforce, thus this also tends to require a stiff anti roll bar.
At the extreme end of this set up characteristic this has been exhibited most clearly in McLarens handling. The car gains traction from the soft rear anti roll bar, but the stiff front roll bar means that the rear heavy car tends to roll at the rear and this picks up the inside front wheel going into turns.
On a side point although McLaren run what has been called a stiff front axle, their apparent problem with grip over bumps going into turns is not necessarily a reflection of this set up, more that the cars aero requires tight ride height control, it is possible to run stiff anti roll bar and still have a compliance for coping with bumps.

Heave is when the car moves vertically, thus both wheels are rising or falling together
In a typical rear suspension the effect of heave is that the heave spring (blue) and each side spring (yellow) is providing stiffness. The dampers (Red) damp the motion.

Roll is when the car tilts, thus one wheel is rising and one is falling
In a typical rear suspension the effect of Roll is the ARB (orange) and the side springs provide the stiffness. Again, the Dampers (Red) damp the motion

Single wheel bump, which tends to be for riding kerbs or bumps in the track is a secondary requirement to heave and roll control, spring rates are not normally tuned for this requirement, instead the cars dampers allow freer suspension movement when the wheel suddenly rises up at a greater rate than normal, the damper has different rates for the wheel rising at different speeds, known as low speed (the cars chassis moving slowly i.e. pitch roll) high speed (bumps) and often a tertiary setting known as ‘blow off’ where the damper will provide a far lower damper rate for extreme wheel speeds such as kerbing.

Hence in both heave and roll the side springs are providing additional stiffness to the effective spring rate, thus both roll and have are coupled to the rate of the side springs. If we can do away with the side springs then both roll and have can be totally independent and controlled by their relevant springs. If you need a softer ARB rate, then the side springs are the limiting factor.

When you do away with the side springs, the heave and roll bar rates are higher in order to replace the spring rate added by the side spring. As long as each of these devices has a wide enough range of springs then there is no loss in control.

It’s noteworthy that both rear dampers are used, in the nineties we saw monoshock front ends, which utilised both a single spring and single dampers. But monoshocks only have one damper so the control of roll is undamped. With a side spring-less set up there’s two dampers, controlling roll motion. Which is an obvious improvement in vehicle control over Monoshocks.
Although there are some set backs with a side spring-less set up, some suspension designers want a non linear rate to the heave and wheel rates and sometimes different rising rate curve for each of these elements. This is achieved by the linkage (pushrod or pullrod) and the rocker geometry, going for side spring-less set up prevents having differing wheel and heave spring rising rates. In some engineers opinions, this is the removal of a needless layer of complexity.
A heave element not only supports the rear axle heave motion, but the element provides a non linear rate. Ground clearance is used up through downforce compressing the suspension as speed increases. The heave element has a range of free movement, this is taken up as ride height lowers until the then the heave spring itself (or Belleville stacks or bump rubbers) come into effect and add considerable rate to the heave motion. This prevents grounding or choking the underfloor through low ground clearance.
Equally making set up changes is both simplified and complicated. Engineers can now change either roll or heave rates independently, before changing a changing torsion bar effectively altered both. But changing a torsion bar, while not a quick task was the switch of an isolated component. Now teams will need to change the entire heave spring or ARB assembly.
An additional benefit is if a team wants to commit fully to the side spring-less set up, the packaging of the suspension becomes far easier, no longer having to package long torsion bars. This is perhaps a reason why Red Bull were able to effectively package the pullrod set up, as the pivot for the rocker is near vertical, fitting a torsion bar in this position would have been be tricky.

With the design of next years car leading towards a widespread adoption of pullrod, the option to adopt side spring-less will be attractive to aid packaging. Although the side spring-less pushrod set up will also allow dampers and rockers more freedom to be packaged at the front of the gearbox casing. Adoption at the front of the car is possible too, there is lesser need as the front roll rate is higher and the torsion bars can add to the effective rate. But simpler packaging and tuning may still be attractive for a designer.

Octobers 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 and Motorsport Magazine.

Automoto365.com – Korea & Japan

This is my major outlet, with my images and writing on race-by-race developments

Japanese GP http://bit.ly/AM365_Japan

Red Bull – Rear wing, beam wing and front wing endplates

McLaren – New F-duct

Renault – Slotted footplate

Williams – Slotted beam wing

Sauber – New diffuser

Force India – New diffuser

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=10&seasonid=21&nextMode=ExclusiveNewsForm&news_id=42674

Korean GP http://bit.ly/AM365_korea

Red Bull – New front brake ducts

McLaren – Slotted front wing endplate

Ferrari – Ridged splitter

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=10&seasonid=21&nextMode=ExclusiveNewsForm&news_id=42861

Motorsport Magazine – Composite Monocoques

I’ve illustrated this article on composite monocoques

http://www.motorsportmagazine.co.uk/2010/10/25/latest-issue-%E2%80%93-december-2010/

Ferrari: Open Fronted Blown Diffuser

The opening in the diffuser (yellow) is blown by the exhausts gasses (red)

On Thursday at Interlagos the F10 was seen with a new diffuser set up, as well as an F-duct with the main plane blown rather than the flap. Ferrari have followed other teams and created an open fronted diffuser.

Ferrari first followed Red Bulls idea of an Exhaust Blown Diffuser (EBD) at Round09 in Valencia. but Ferrari chose to blow the exhaust over the top of the diffuser. Where as Red Bull had created an opening into the diffuser, so that the exhaust blows both over and under it. At Silverstone Red Bull opened the diffuser up in two more places each side.

Closed diffuser: the exhaust gas (red) blows over the top of the diffuser (yellow)

Having an open front to the diffuser and directing exhaust flow into it, speeds up the airflow through the diffuser creating more downforce. As with all EBD’s the trade-off is the variation of downforce according to throttle position. To some extent the positioning of the exhaust well upstream from the inlet reduces this effect, as does the engine mappings that retard the ignition and keep the exhaust flow moving even when off the throttle.

Open Diffuser: the exhaust gas (red) enters the slot and passes inside the diffuser (yellow)

Since Mid season both Williams and Mercedes have created open fronted diffusers. In Mercedes case the 800c heat from the exhaust created problems with the diffuser rigidity. Detail design heat shields and improved materials, such as ceramic composites (i.e. Pyrosil) have allowed the exhaust flow to pass directly over the diffuser surface without thermal problems.

Ferrari’s late introduction of the open fronted diffuser and revised F-duct is at odds with statements from the team back in Singapore that the cars development had finished to focus on 2011. Either Ferrari have reignited their development programme as their championship fortunes have reversed with wins in the late season races. Or perhaps the comments meant that the development of the parts had finished, i.e. the design phase was over, but the manufacturing and testing were still in progress.

Clearly these parts do not come from any 2011 programme as the draft rules will ban openings in the diffuser. Although these rules are aimed at eradicating the double diffuser, the wording prevents 50mm openings in the outer portion of the floor (where the flat floor meets the diffuser). Thus open fronted diffuser are effectively banned as routing exhausts that far outboard are impractical. In 2011 downforce can still gained by having the exhaust blowing over the top towards gurney flap to speed flow the diffuser. Equally the f-duct is banned in 2011 replaced by a driver adjustable rear wing.

Red Bull Pull Rod suspension: What is looks like – How it benefits aerodynamics

Adrian Newey’s lateral thinking in 2009 gave rise to the modern iteration of pull rod rear suspension. Although handicapping the double diffuser, the solution remained on the Red Bull cars for 2010. With double diffusers being banned for next year, other teams are looking at the concept. Lotus Technical director Mike Gascoyne has even cited the opportunity to exploit pull rod suspension as a reason for going with Red Bull Technology for the supply of their 2011 gearbox. Pull rod may well be the buzz word at the launch of many of the 2011 F1 cars.

Red Bull have been running a pull rod rear suspension since 2009, while not a new solution, no team had run this set up for many years, as the aerodynamic demands of the rear diffuser drove designers to place the spring and damper hardware up above the gearbox to create space for tunnels beneath the car.

F1 rear suspension.

What the various suspension components are

F1 cars operate substantially similar suspension front and rear, the packaging varies each end but the main components are the same. Double wishbones control the wheels attitude and from the outer end of the wishbone a rod controls a rocker that then activates the various elements that control the suspensions compliance. Firstly the springs are in the form of torsion bars, these are like straightened coil springs and their resistance to twist provides the springing medium to support the cars mass. Then the dampers, one for each wheel, these control the movement of the wheel as it raises and falls (bump and droop). The antiroll bar controls the amount of weight transfer from one side of the car to the other. Lastly the third spring, also known as a heave damper control the pitch movement (both wheel bump or droop simultaneously) This is especially important to prevent the downforce load pressing the car against the track and bottoming the car on the ground at high speed. Teams may also fit an inerter in this position to offset the uncontrolled bounce of the tyres having an effect on the chassis.

Pushrod suspension: the high location creates free space either side of the gearbox for diffusers

When the rods operating the rockers start out low at the outboard end of the wishbone and rise up towards the rocker, this is known as pushrod, as the rod pushes the rocker when the suspension is in bump. Conversely when the rod falls from the upper wishbone to operate a low placed rocker, this is known as Pull rod as the rod pulls the rocker.

Pullrod suspension: note the space freed up above the gearbox

Pull rod is nothing new, it first appeared in 1974 when Brabham designer Gordon Murray applied to the design to the front of the BT44. Murray admitted he saw the idea in a Hill climb car and simply applied his version of it to the F1 car. The alternative suspension designs of the time were either an outboard spring\damper, which was un-aerodynamic and restricted damper movement to that of the wheel. Or rocker arm suspension, with required large and heavy upper cantilever arms to operate an inboard spring\damper. This was heavy and only provided a low ratio of wheel to damper movement, but was moderately better aerodynamically. The pull rod employed light wishbones, placed very little structure into the airflow and gave the opportunity to alter the rate and ratio of wheel to damper movement. Murray subsequently turned Pullrod upside down to create the pushrod for the front suspension of the 1983 BT52.

Red Bulls Adoption of Pullrod

When the aero rules changed significantly for 2009, most teams adopted fairly conventional approaches in the chassis design to accommodate the changes. One of the major aero changes was the switch to a much smaller rear placed diffuser, The loss in potential downforce from the smaller diffuser, made the rear wing performance a greater contributor to the cars total downforce.

As intended the single diffuser freed up space around the gearbox and made the rear wing more critical

Newey’s thinking for the RB5 was to create a low-line rear end, by placing the differential unusually low and switching from pushrods to pull rods. With the smaller diffuser runnels and moreover the tunnels starting as far back as the rear axle line, well behind the main body of the gearbox. This gave Newey the space to package the pull rod hardware and not interfere with the diffusers tunnels. As a result the airflow over the top of the gearbox to the rear wing was far less obstructed by the pushrod operated springs and dampers. This solution was clearly valid as the RB5 was the only car with a single deck diffuser to challenge the Brawn cars. However it exactly the reason the Brawn was so fast, that undid Newey’s low-line rear end philosophy. As the Brawn had a Double Deck diffuser (DDD) this solution found a loophole in the rules that created a secondary diffuser tunnel starting much further forwards and rising much higher. Suddenly in the race to also exploit this loophole, Newey found his Pullrod set up was occupying the exact same space that the DDD needed for the upper tunnels. Newey chose not to design a completely new rear end, and compromised the design of his DDD within the constraints of his pull rod suspension.

With a double diffuser the longer taller upper deck occupies space around the gearbox

For 2010 the car was designed with a DDD in mind, Newey was able to repackage the pull rod set up for even larger tunnels. He said that the choice of Pullrod for 2010 was still not the obvious way to go, but the team decided to stick with a proven pull rod rear end, rather than have to design an all new rear end. Other teams also looked at the feasibility of a Pullrod rear end, However no other teams followed this design path, with the exception of the Toro Rosso team who used the RB5 design in 2009 and simply revised it for their 2010 car. For 2011 the DDD is banned, with revised wording in the technical regulations outlawing the openings beneath the car to allow air to flow into the upper diffuser deck. Thus again we will see teams consider the pull rod layout for better airflow to the rear wing.

Which is better – Push or Pull

In terms of their effectiveness as controlling the wheels, both are equal. In terms of effect on aerodynamics each has its merits depending on the prevailing rules and trends. However both have different benefits and demands on the chassis. Pullrod clearly provides a lower CofG, although access can be an issue. In Red Bulls case they place the 3rd spring and inerter horizontally across the front of the gearbox. This means one sits above and the other below the shaft connecting the engine to the clutch. These can only be accessed when the gearbox is removed and are subject to a lot of heat. Although Newey tells me that they do not suffer unduly because of this. One difference is in the load passed through the wishbones.

Reaction forces (Red Arrows) mean pull rod placed higher loads on the upper wishbone

As per Newton’s third law, the rod has to react to the force of the springs. This passes back from the rocker to the mount on the wishbone. In pushrods case, this reaction force is in the opposite direction to the force fed from the wheel into the chassis, the two offset each other. With Pullrod the force from the rod and the wheel act in the same direction, this doubles the load in the upper wishbone and resultantly in the mounting the gearbox. This can be accounted for design and weight of the final wishbone design. However Pushrod also has its structural problem, the pushrod when the suspension in in bump (wheel rising) the rod is in compression and would tend to bow outwards. The pushrod was the first suspension component to have carbon fibre cladding for reinforcement, again design and weight is needed to offset this load. Suspension experts point out that Pull rod suffers similar compression bending when the suspension is in droop (wheels falling), but droop is considered less critical in wheel control, than bump. There’s no one answer to which is best, you look at your design requirements and pick which solution works, best. Next year the best car is not necessarily going to be the one with Pullrod rear suspension.

Pullrods at the front?

Minardis 2001 PS01 used a low nose and pull rod front suspension

This was a favoured design for many years, even after Murray innovated with the BT52. However designers found they could slim the nose cross section by mounting the spring\dampers above the drivers legs and no longer to each side of his shins. This improved access, even if it did compromise CofG slightly. Then as the raised nose aerodynamic concept took hold, teams found the gains from a high nose, offset the CofG gain of pull rod suspension. Arrows campaigned their A21 in 2000 with pull rod front suspension, and latterly Minardi ran the PS01 with a relatively low nose in 2001. Each team subsequently moved to a fully raised nose pushrod suspended car. Now the front of the chassis is raised too high for a pull rod to work, the angle from the upper wishbone to the chassis is nearly horizontal. This geometry meaning that almost no movement of the pull rod will occur as the suspension moves. Making the set up structurally inefficient.

Analysis: Lotus to use bespoke Red Bull gearbox and hydraulics from 2011

Although the rumours suggested it will be a complete Renault rear end for Lotus Racing, today the team announced it will in fact use the Red Bull gearbox and hydraulics from 2011.

Equally unexpected was the confirmation that the technology will not simply be Red Bulls 2011 RB7 design. But a part Lotus designed gearbox. Silvi Schaumloeffel from Lotus exclusively telling ScarbsF1.com “It’s a bespoke gearbox for us and we have been in contact for several weeks and have been able to progress the design”. Thus the 2011 Lotus already has the Gearbox design considered as part of its initial philosophy.

This deal underlines the determination of Lotus Racing to get a foot hold into the midfield. Their race results this year have been undermined by hydraulic failures. Lotus Racing are one of the two teams using the complete Xtrac gearbox and Geoff Willis technical director of HRT has been critical of the units packaging in comparison to current F1 standards. Clearly if Lotus want to progress then they need to resolve the reliability issues with the cars rear end. Moreover the team also need to improve their aerodynamics, at the rear of the car this is largely constrained by the gear case design. As the gear case itself forms a large obstruction to the airflow approaching the diffuser. Plus the gearcase dictates the rear suspension geometry, spring\damper packaging and the hydraulics packaging.

As a route to a cheaper and quicker entry into the Formula, the FIA allowed new teams to run with an Xtrac gearbox and hydraulics, mated to the specification Cosworth Engine. Lotus have taken this approach, of the new teams only Virgin chose to make their own gearcase, the bespoke case gave Virgin a unique rear wishbone geometry.

Traditionally teams have always developed their own transmissions and hydraulics, albeit with assistance from specialist manufacturers, but the concept, design and assembly has been in the teams’ hands. While gearboxes have increasingly been reliable from both detail design work and the increased control from electronics, the F1 cars Achilles heel has recently been the hydraulics package. The hydraulics package is complex both in its operation and the number of moving components controlling the various systems around the car. A modern hydraulics system now controls: gear selection, clutch, differential, reverse gear, throttle control & power steering. Any number of components can lead to the system breaking: pump failures and leaks, plus failures of the valves or actuators.

To build up the knowledge and resources to develop a complete gearbox and hydraulics, requires time and a huge investment. Equally with restricted testing, problems with any part of the system could hinder pre-season testing and lead to yet more race retirements. As a medium term option Lotus have taken the route to sub contract these systems to another team who already have the knowledge resources and a proven product. Several teams have offered these systems to other teams, Williams are known to be marketing their rear end, while before the Red Bull announcement, Renault were believed to offering their rear end.

The option to take a team’s gearbox and hydraulics is logical; the choice of any of the current team’s solution would be equally attractive. Why Lotus chose Red Bull is not yet clear. Perhaps the fact they are able to offer a bespoke product, rather than the same specification as raced by the factory team.

Looking at Red Bulls recent history on transmission and hydraulics does not initially paint a positive picture. In the first years of Newey’s tenure at Red Bull racing their systems were unreliable, it took the recruitment of Geoff Willis to iron out the faults, since then and following his subsequent departure, RBR have been as reliable as their rivals in these areas. Red Bull were also late to the seamless and carbon fibre trends on gearbox design.

In contrast the influence of Newey on gearbox design shone in 2009 when he designed the RB5’s gearcase to accommodate the new aero regulations. With smaller diffusers mandated he took advantage of gearbox packaging to improve flow to the rear wing and around the diffuser. Only the advent of double diffusers upset this philosophy. Newey’s 09 gearbox took a low line approach, placing the differential low down and moving the springs and dampers from atop the gearcase to low down, by use of pullrods rather than pushrods. This placed the torsion bars splayed vertically aside the gearbox and the dampers running longitudinally alongside the case. While the heave damper and inerter sat inside the front of the gearcase, either side of the clutch input shaft. Having these components in this location placed them low from an aero and CofG perspective, plus they sat in the shadow of the engine, thus once faired in beneath bodywork presented no interference to airflow alongside the flanks of the gearbox. In contrast to the low line mechanicals, the wishbones were mounted unusually high, the lower wishbone was well above the floor (leading the space for the exhaust blown diffuser in 2010), then the upper wishbone sat very high up on pylons cast into the top of the gearcase, the rear legs of the upper wishbone taking a secondary aerodynamic role in directing airflow the rear wing.
It was only later in 2009 that the team switched from cast aluminium to a carbon fibre gearcase. The switch in material having no major effect on the original designs packaging.
For 2010 Newey’s gearbox needed to accommodate the double diffuser, the original concept was largely retained, only a raised differential and revised wishbone geometry (to optimise the EBD) were altered. Newey did tell me the benefit of pullrod was marginal, it being better to stick with the known concept than alter the entire case for pushrod operation. With the ban on double diffusers in 2011, Newey’s original 09 concept will see benefits once again.

Of course Newey’s gearbox layout won’t necessarily be copied, as the Lotus gearbox will be a bespoke product, Mike Gascoyne’s Cologne based design team will be able to influence its design. However it would be logical for the team to follow some of the concepts used by RBR in 2009. Although perhaps the choice of a cast metal casing would be more effective for Weight VS cost, Carbon would be expensive and 2011 cars are constrained by the demand for forward weight distribution that RBR faced in 2009. Gascoyne does have a record of innovative gear cases, with his split carbon fibre\Cast Ti case at Renault, then Toyota using fully cast Ti cases and latterly Midland\Spyker\Force India with cost effective cast aluminium cases.

For Lotus to truly be a leading team they will need to build up their own gearbox and hydraulic departments. This deal for RBR technology will allow them to naturally evolve these resources, while racing their bought-in gearbox.

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

F1 Tech in ‘Race Engine Technology’ Magazine

This months ‘Race Engine Technology’ magazine has some interesting stuff for F1 Tech followers. There’s an interview with Mario Ilien, who explains the work he did with Mercedes-Ilmor including; Hydraulic KERS, a rotary valved V10 (+20k RPM & 78Kg) and of course Berylium for Pistons & Liners.
In the Report from the F1 British GP, the Editor interviews Adrian Newey, Also Costa, Sam Michael and James Allison. Covering several topics; the effect of engine power\drivability\consumption, as well as gearbox design influence on aero, with Newey commenting the Pull Rod was a carry over from 09 & not a requisite for his RB6 design. While Ferrari confirmed their engine\gearbox assembly is inclined at over 3-degrees, the first time I’ve seen a reliable quote confirming this fact. It was added that Sauber take this set up for their C29, while Toro Rosso have their own gearbox so have a horizontal drivetrain.
Lastly is a small section on how Sauber pioneered current gearbox design with a longitudinal gearbox, with the gears ahead of the final drive and contained within an aluminum case. It surprised me that Harvey Postlethwaite was involved in this, is there anything that man didn’t do in F1?

Not generally available in the shops and not cheap, but well worth a one-off purchase or subscription.

http://www.highpowermedia.com/mall/productpage.cfm/RET/2049/348121

RACE ENGINE TECHNOLOGY 048 AUGUST 2010

Intro: THE EDITOR
Racing powertrain technology is on the verge of a revolution; Ian Bamsey says this issue gives some hints as to what to look for

Upfront: MARIO ILLIEN ON FUTURE TECHNOLOGY
Ian Bamsey talks to Mario Illien about his pioneering work in Formula One during the V10 era and the future of race technology

Grid: IN THE NEWS
Peugeot’s con rod dramas; HPD’s new LM P2 V6 turbo; Le Mans’ Hybrid u-turn; John Medlen’s new role at DSR and much more

Dossier: PORSCHE 911 GT3 R HYBRID POWERTRAIN TECHNOLOGY
Ian Bamsey investigates how flywheel-based storage of recovered kinetic energy has been pioneered in professional racing

Race Report: BRITISH GRAND PRIX
Despite the ongoing engine freeze, Ian Bamsey discovers some significant powertrain developments at the British Grand Prix

Focus: CAMSHAFTS
Wayne Ward discusses the options available for the design, materials and manufacturing methods for race camshafts

Insight: RACE ENGINE INSTALLATION
Le Mans-winning designer Peter Elleray on the relationship between engine and chassis design, highlighting where their needs conflict

Focus: THE GEARBOX
John Coxon explains key points in designing and building a motorsports transmission – from the gear teeth to choice of differential

Race Report: LE MANS PROTOTYPES
Ian Bamsey gives a rundown of the various engine strategies deployed by this year’s Le Mans Prototype competitors

PS: SAUBER C12 TRANSMISSION
How in 1993 Sauber’s first Formula One car prompted a major shift in transmission technology

To view a sample article from this issue please click here

Price £12.50

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.’ “