F1technical.net

Another photo of the rear.. note the temp stickers on the top as well as the underside of the diffuser..

sorry about the lack of focus

(Click image to head through to my Flickr feed from the Melb GP.)

Hello everyone! You've got a really nice forum here, a bunch of very knowledgeable people. I don't think I can contribute much because I'm just a fan without any technical knowledge, but I'll enjoy reading you from time to time.

The only reason I've registered is that I was reading this thread and saw you're discussing about the grey diffuser the McLaren's had in Australia. Pedro De la Rosa explained during the tv coverage of the race -he is a comentator for Spanish tv channel La Sexta, together with Ferrari's Mark Gené and a couple of sports commentators, that it was a carbon fiber diffuser painted with a kind of paint that offers thermical protection. The reason for this was they only managed to build one for each car in time for the weekend so they couldn't risk any kind of damage. I hope this helps.

My thoughts were...
They were using a metal with a high coefficient of thermal expansion. This would allow the size of the diffuser and holes in it to enlarge when heated by the exhaust gases during the race but return to regulation size when cooled. This would allow them to be in compliance, pass scrutineering, and gain an aero edge. Not a rules violation just smart engineering.

This is all speculation however.

The cars are on a different piece of race track. Look at the white lines on the track surface. There are two lines at the rear of the RB, one behind the McLaren.

However, the rear wheels line up perfectly here, the fronts are just about the same but the difference in wheelbase length makes it difficult to be sure. The wheelbase length is markedly different with the -26 being a lot longer.

Stigmacher wrote:My thoughts were...
They were using a metal with a high coefficient of thermal expansion. This would allow the size of the diffuser and holes in it to enlarge when heated by the exhaust gases during the race but return to regulation size when cooled. This would allow them to be in compliance, pass scrutineering, and gain an aero edge. Not a rules violation just smart engineering.

This is all speculation however.

Enlarge two microns? lol

Stigmacher wrote:This would allow them to be in compliance, pass scrutineering, and gain an aero edge. Not a rules violation just smart engineering.

Um, it is still a rules violation. Compare it to speeding on the public road. Just because the police don't catch you doesn't mean your not breaking the law.

The rules say "though shall not do X". If you do X then you're in violation of the rules.

Just because they don't catch you doesn't mean you're not cheating...

Scarbs confirms that the diffuser was titanium with a zircotec coating.

Mclaren: Whitmarsh confirms "We had to build the diffuser entirely of titanium which, of course, cost us some extra weight" ....!

why would you need to coat titanium?

747heavy wrote:why would you need to coat titanium?

i should imagine it was precautionary, any warping of the titanium could contravene the rules, and the couldn't risk any kind of damage to the diffuser as they only had 1 per car

I wonder just how much could be that extra weight ? Can it impact the car's performance ( assuming they have enough balance weight to adjust the CoG-effect of that extra weight ) ?

How is it faster to produce it from titanium? You still have to create moulds, etc. Layup and baking should be a non factor, really in the time to fabricate. Maybe McLaren are having problems laminating CF for high heat? Now that i think about it they have had some issues in the past with parts that couldn't take heat well, like when they first tried DD diffusers.

747heavy wrote:why would you need to coat titanium?

its light and fiarly heat resistant but when it cools it does not cool uniformly and deforms.
Evidence of this can be found by interviewing a maintenance mech on the LockHeed SR-71 blackbird.

After every mission they have to panelbeat the nosecone (titanium) and wings bac into shape. Titanium is quite soft yet tough and anythng less than perfect heat distribution results in a rather bent looking cooled component.
We saw this in recovered rocket motor nozzles as well. They look pretty banged up after long burn. we thought it was damage due to the recovery. Nope they just got bent out of shape due to uneven cooling.
The Zircotec I assume distributes heat more evenly across the titanium surface.
Reinforced Carbon carbbon wouldbe a better material but it takes a few weeks just to mould the part..
titanium is easier to work with if you need to make a part quickly since it can be formed over an external shape or even an anvil

BreezyRacer wrote:How is it faster to produce it from titanium? You still have to create moulds, etc. Layup and baking should be a non factor, really in the time to fabricate. Maybe McLaren are having problems laminating CF for high heat? Now that i think about it they have had some issues in the past with parts that couldn't take heat well, like when they first tried DD diffusers.

There won't have been any press tools (moulds), it will have been hand beaten from sheet using English wheel, etc., very similar to the manner in which Aston Martin use to make body panels, in several pieces and then welded together to form one floor.

Two weeks to produce two floors and maybe one spare, tight but by no means impossible.

the fact that McLaren can produce two such components in such a short space of time and still deliver performance is surely a clear indicator that they now what they doing. I still have a lot of confidence that they will challenge RedBull this year for both titles.

What temperatures do you suspect the titanium starts warping?
I have another guess that it is creep they are trying to prevent. which yes it connected to warping. But I think creep is more dangerous because of the types of vibration and loads the diffuser sees.