Toro Rosso have released a youtube video of a complete factory tour. Both informative and in depth, the video shows us some detail of the car we do not usually get to see.
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 frontsoft 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.
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
Korean GP http://bit.ly/AM365_korea
Red Bull – New front brake ducts
McLaren – Slotted front wing endplate
Ferrari – Ridged splitter
Motorsport Magazine – Composite Monocoques
I’ve illustrated this article on composite monocoques
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
I’ve illustrated this article on this years must have developments: F-ducts, Exhaust Blown Diffusers and deflecting splitters.
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.
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 powerdrivabilityconsumption, 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 enginegearbox 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.
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
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
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.
As you can see, the upright failed towards the top mounting (top right in this picture) where the top wishbone and steering arm connect.
In Free practice to day, Toro Rosso suffered a massive front suspension failure. The team have put this down to the failure of the upright. An upright is the component that links the suspension wishbones to the axle and the wheel. It appears the upright was new and from a batch not previously used. Its not clear if the upright was a new specification or a newly manufactured batch of the existing spec.
Due the multitude of functions the upright has to accommodate, it is subject to enormous stress. This is particularly found under braking as the upright has both the load from downforce, braking and suspension movement. An upright is joined to the suspension at three places; the upper wishbone mounts via a spherical bearingcamber plate bolted to the top of the upright, the steering arm via a spherical jointclevice bolted to the uprights front edge and the lower wishbone normally attached with a spherical joint bolted directly to the bottom of the upright. Then the brake caliper bolts to the upright in two places, lastly the axle (hub) rotates in two large diameter bearings through the middle of the upright.
Uprights were commonly made from titanium or MMC up until this year, when the rules were changed to demand aluminium. The BBC TV sports broadcast wrongly suggested they were made from carbon fibre, No Carbon upright has raced in F1. The metal upright is castmachined, rather than the previous practice of welding various parts together, this is due to the different layout of the modern F1 upright, which no longer places the hub in relatively small bearings inside a vaned mounting to pass cooling air to the brakes. Instead the bearings are larger and the upright wrapped more tightly around the hub, the cooling air now passing around the upright via the carbon fibre brake duct. Only BARHonda had a different solution, which routed the cooling air inside an oversized hub to the brake disc. This set up compromised the packaging for the Brawn BGP001, leading to its relatively low nose. For 2010 Mercedes (nee Brawn) have more conventional uprights.
In Toro Rossos case the point at which the upright failed is yet to be confirmed, if it will be made public at all. Most likely the point at which suspension loads pass into the upright will be the area of highest stress and likely to cause the type of catastrophic failure we saw in Shanghai. Thus the failure could equally be attributed the wishbone ends or the camber plate, rather than the aluminium upright itself.