Renault 'hybrid-wishbone' on rear end?

[ginsu]

Imola 06 pre race



I'm not totally sure this lower wishbone is new, but it's the first time I've seen it. It looks like it is half metal (Ti) and half carbon. Is this true? It's certainly interesting, and I wonder what it's effects are?

[scarbs]

I'm pretty sure thats just sleeving for heat protection, But I wil dig out a higher res pic.

[manchild]

I'd agree with ginsu. If it was heat protection than logic would tell to put it on upper wishbone not lower. I think it has something to do with high kerbs in Imola and reliabilty of suspension.

[NickT]

This has to be a fairly beefy component as it not only has to deal with a the forces in bump and rebound but also trying to control those additional forces resulting from driving the wheel with 300 to 500hp. It is also in very close proximity to the exhaust manifold to.

[pyry]

isnt carbon fibre more durable than metal in terms of mass and even size?

[RacingManiac]

I know for a fact from one of the interview with Adrian Newey last year(Race tech or racecar engineering) that McLaren runs steel lower rear wishbone because of load requirement.

In this case though I think its a shrud....even though upper wishbone may seems to be more critical interms of temperature, it is in the airstream and it may be enough combined with the heat shield and the wishbone being loaded a lot less, that it is not an issue. With the lower carrying more load and being pretty much enclosed in the chassis with header that may run right by it(a guess), that it may need more thermal protection...

[scarbs]

I have looked at all my 2006 Renault Gbox shots, it wasnt on in Bahrain but has appeared since then.

Its clearly a shroud as fits around the outside of the mounting clevis.

Theres been no heat shrouding on the upper wishbones, but as these sit within the bodywork they may be protected from the exhaust heat. in fact the lower wishbone is well clear of the rad outlets and exhaust. so the part may be simply an aerodynamic shroud working with the inner sections of the diffuser.

I'm not sure the reason it isnt made of more normal carbon, may be the heat proof material is lighter than structural carbon?

[ginsu]

Yes, it definitely wasn't on in Bahrain. And I agree, it must be aero. I guess I thought it was structural because it looks like Ti, but I've heard of white carbon, so it may not be Ti. If it is Ti, then I am still quite confused. It wouldn't make any sense to make a fairing out of Ti.

[DaveKillens]

I'm sure most of us have viewed pictures of engines being run on test stands, and the headers run red hot, They have an incredible amount of heat in them and being generated. And the gearbox lives right behind the engine block, it's that close. Although I don't know the exact layout of the Mclaren headers, it wouldn't be beyond my belief if the lower suspension arm is within nine inches of the header.
If they are running some kind of protective shroud, titanium makes sense. Aluminum would melt at that level of heat, steel would be too heavy, and Ti would fit the bill.

[ginsu]

I agree with you dave, except I don't know why they wouldn't shield the upper wishbone in the same fashion. It doesn't make sense to do it for the lower wishbone, but not the upper if it was just heat related.

[manchild]

What if it is there to reduce flexing of wishbone and prevent snapping?

I say - titanium sleeve for protective purpose due to demanding kerbs in Imola. If they were concerned about heat than they would have golden foil at least in Bahrain and Sepang but as we’ve see that wasn’t the case.

[Reca]

The metallic shell was there on the R25 too. Sometimes you don’t see it on pictures of gearbox but it’s very likely just because it isn’t mounted yet in that moment, in fact it was there in Bahrain too as you can see for example from this pic :
[IMG:152:130]http://img240.imageshack.us/img240/923/ ... 0zz.th.jpg[/img]

As for the reason why it’s mounted on the lower one and not the upper one, as other noticed, the lower wishbone is in the flow coming out from sidepods and it’s also very close to the header and exhausts. As you can see also on the above pic the upper one is out of the bodywork and apparently it isn’t even affected by the hot exhausts flow. There are temp sensitive stickers on the upper wishbone so they have the situation under control, they would immediately know if there was the need to protect it.

If they were concerned about heat than they would have golden foil

A shield like that one, if really is Ti made, could easily stand lot higher temp than what it’s subjected to there. Additionally it has practical advantages compared with golden foil, for example it’s very easy to mount and remove and a single shield could probably last for a season even if you change wishbones every 300 km.

[RacingManiac]

I'm sure most of us have viewed pictures of engines being run on test stands, and the headers run red hot, They have an incredible amount of heat in them and being generated. And the gearbox lives right behind the engine block, it's that close. Although I don't know the exact layout of the Mclaren headers, it wouldn't be beyond my belief if the lower suspension arm is within nine inches of the header.
If they are running some kind of protective shroud, titanium makes sense. Aluminum would melt at that level of heat, steel would be too heavy, and Ti would fit the bill.

McLaren's reasoning was actual load not temperature....I am sure if Titanium was an option they probably would've used it...

[manchild]

Ha! I was right, those are titanium sleeves!

Check how thick they are!

http://www.gurneyflap.com/Resources/DSC_1896.jpg
http://www.gurneyflap.com/Resources/DSC_1864.jpg

[Tom]

OK, don't gloat , very meaty arms, the suspension I mean, not the merchanic in the background.