Renault's Dynamically Adjusable Camber

[NickT]

I read a little while ago about Renault and Michelin's work on a suspension design that maximises grip by adjusting inside and outside wheel camber, mechanically through the steering input of the driver.

Basically this gives varing degrees of negative camber to the out side wheel and positive camber to the inside wheel while cornering, thus maximising lateral grip. While travelling in a straight line the tyres are held in a near zero camber position to maximise linear grip for breaking and traction.

Does anyone have any more details?
Is it still being tested and developed?
Is it only applied to the front wheels?

[KeithYoung]

I beleive the system is called the OPT system, and I beleive it is mostly mechanical linkages etc in the upright. I will have to dig up some old magazines, I think an old racecar engineering covers the system. Until then

http://forums.atlasf1.com/showthread.ph ... hlight=opt

hopefully the link works. Anyway have to run.

[pabs]

There was a good article about it a few months ago in Autosport. I'll see if I can dig it up.

[Monstrobolaxa]

The OCP also works according to the suspension movement...not only according to the steering input.

[scarbs]

The system is a Michelin patented solution called OPT, of which Renault uses one of many alternatives under the title of OCP. They have run the system through out the year in testing (fact not rumour) but is used on the REAR.
I have images and text I can send you on the systems principles, but in essence the system uses a two piece upright which pivots through a virtual roll centre and by the action of the toe link operating a second link between the two pieces during roll, the uprights open\close to correct camber.

The image on the above Atlas link is INCORRECT for the system adopted on the Renault. I wrote a stories in Racecar engineering and AtlasF1 detailing the system based on images of the test car and the Michelin patents. Alas images of the actual upright assembly have been impossible, but the distinctive brake duct gives the game away.

Williams have been rumoured to run a variation of the OPT patent on the FRONT, but I have not been able to confirm this, but I suspect the upright is split horizontally and the pushrod rod length altered to adjust camber.

[NickT]

I would really appreciate it if you can post the details particularly the pics. If not can email them directly if that’s easier, but then no one else would benefit. I am really interested in how it works and what actually causes and controls the camber change. Pics really help me, words are fine and give me a feel for what’s happening but as I am dyslexic so the pics really help me understand what is going on. (Just in case you are wondering, MS Word has excellent spelling and grammar checking)

I am surprised it is only used on the rear suspension. With the lack of front down force, the current tyres requiring more of the static weight distribution, I would have thought they would have been the first point of application. Perhaps turning complicates things too much at the moment.

Really disappointed I didn't know it was at the rear! I was climbing all over the front suspension of a R23 at the Mount Stuart Classic looking at the Ackerman angle (looks like its zero) and suspension location, attitude and mounting (flexures). One thing that did amaze me at the rear was the angles the drive shafts have to turn through. It looks like Aerodynamics are dictating location, rather than trying to keep them straight and true as per the textbooks.

Hmmmm.... does anyone know if there is perhaps a traction advantage in having the drive shafts angled?

[scarbs]

Heres the link, to the simplified article I'll get the tech pics from my other laptop later in the week.

http://scarbsf1.com/renault_opt/Renault_OPT.htm



OPT is easier to hide at the rear, plus traction is also an issue with the wider tyres. I have no doubt it has more potential to be effective on the front.

Why would you be surprised not to see it on the RS23 show car, they wouldn't run OPT on that in such a public place, the Renault engineers were almost aggressive hiding the car at the Silverstone and Barcelona tests!

Driveshafts angling backwards are often more for weight distribution, but I have heard that traling rear suspension is good for traction too, as it is use don off road buggies etc.

[NickT]

Many thanks scarbs, really appreciated and I can’t wait for your tech pics to.

I cannot find a copy of Race Car Engineering anywhere! How do I get a copy and how does it compare to Race Tech?

Cheers

Nick

[NickT]

PS Wicked web site Guess thats my evening reading sorted for the for the next week !

Thanks again

[scarbs]

Cheers for the comment on SF1.com, I have some more updates for it over the next week.

Racecar engineering can be bought over the counter in the UK US and Australia. (In the UK try larger WH Smiths).
They have a website “racecar-engineering.com” that gives some info on the latest issue and subscription details. In comparison to RaceTech the content is more detailed and technical, the coverage is more article lead than RaceTech’ transcripts of interviews. RaceTech tends to focus on club motorsport competitors and small volume builders, RCE tends to be for people in the industry.

[Sean]

Mike Gasgoyne Gave a lecture series at University of Southampton During his recent gardening leave.
he said they never raced it, because the aerodynamic disadvantages slightly outweighed the mechanical advantages
Sean