McLaren MP4-26 Mercedes

[donskar]

@Ringo

Don't give up on McL just yet. They have lots of good people and they know how to develop a car. And it's no shame (or surprise) to be slower than a Newey car.

[forty-two]

Any ideas why McLaren felt the need to wrap the bottom of the end of their crash structure in black duct tape?

Also, since when was the rear of the floor covered in what looks like shiny metal?

[Just_a_fan]

...Not sure it's what McLaren are doing though.

But that wasn't really where you came in here, was it, you were talking about optical illusions and viewer mistakes.

But that's for later, let's not get ahead of ourself, can we get any agreement, any consensus on the basic question of apparent floor asymmetry or not in that image? That would seem to me a logical first step in any discussion.

I think my position is clear - it's optical illusion and they are running a symmetrical car.

As for consensus, good luck with that on here!

[Just_a_fan]

The other mildly interesting thing on that image is the temperature sticker, from the close-up it looks to read a temp of around 90°C. (Well greater than 88 and less than 93)

Well, we know that the exhausts discharge in this direction. The rear of the gearbox area is shaped to channel air (or exhaust gas?) in to this area. What is interesting is that the diffuser gurney is massive in this area and links to the underside of the crash structure. Presumably they're trying to get exhaust through the starter hole either that or they're not getting the flow where they originally wanted it to go.

I'm guessing that the original design concept was for the exhausts to discharge "below the floor" (or whatever they've been trying to do with their exhausts). The gearbox area was shaped to improve air flow above the diffuser etc.

Anyway, with the "conventional" exhausts shown in the picture above, they're obviously having to check temps in various places. As you say, 90degC is pretty hot for that sort of location. Makes you wonder if they're actually doing quite good job of blowing over the diffuser after all. Maybe it's too good...

[kalinka]

Hmmm...maybe it's soo good, they have to cover the floor with that shiny metal that forty-two pointed.
Other thing > Any rumor on what's the specific reliability issue thay had ? As I understood it's related to exhaust, but what it could be? Overheating, or some mechanical/structural thing ? I didn't hear any report on track that the car sounded strange ( which could point to cracked exhaust ), so I think it's more possible an overheating issue....

[thestig84]

(Autosport board found radio lemans clip it : http://hunnylander.wordpress.com/2011/0 ... roblem-is/)

I emailed my friend that link from radio lemans guy stating what he had heard about Mclarens problems. He wrote back...

That backs up what I have heard. The shape and length are the issues apparently. As they are not round, when hot they are disforming to circular (bit like a ballon will always be round) and the length just can't cope with the stress/vibrations.

Sort of good/bad news. Good if they can fix it then it will be like finding a silver bullet. Bad is pretty obvious really. If it gets scrapped the whole concept is compromised and planned upgrades useless.

[KeiKo403]

Even Alonso has said that McLaren are going to be fast. Deep down we all know it too, maybe we just don't want to shout about it for fear of jinyxing them.
Anyway, about the FW symm, it doesn't matter. If both sides are the same then it's just an optical illusion. If not then they know what they are doing and it explains no fast times being set. McLaren have never really been about using testing to pull in sponsors with fast laps. They use it for testing! I have faith in them.

And now to play a 100% race distance of Melbourne in F1 2010! As McLaren of course.

[kalinka]

The shape and length are the issues apparently. As they are not round, when hot they are disforming to circular (bit like a ballon will always be round) and the length just can't cope with the stress/vibrations.

If it's true, it's good news IMO, because that clears up some things for me.

1. It was unlikely even for McLaren that they can came up with a new exhaust pipe design in 2-3 days when they realised it doesn't work in Barcelona. So that explains why they can't fix it on track. You can't do much with cracked exhaust other than change it.
2. It's an understood problem, and not some "gremlin" that appears here or there randomly which would be really a nightmare to solve.
3. It's a problem that I'm sure they can solve. Maybe it'll weight a little more.

Of course we can't be sure on that source

[speedsense]

The other thing is the amount of hydraulic problems they have had, one or two in an year would seem "normal" but 4-5 failures in the test sessions? As the hydraulic systems vary on the car, brakes, shifting, clutch, etc. ... why all of sudden is the car experiencing hydraulic failures? New systems? new usage for hydraulics? Heat related problems due to the exhaust changes?....
Haven't heard much about any other problems other than the exhaust and hydraulics, except the one motor change.... outside of that, what other problems are there or have been spoken about?

[thestig84]

Of course we can't be sure on that source

I can assure you Im not making it up. Check my previous posts in which I refer to my source. I mentioned the L shaped sidepods on here a month before launch. Obviously he just hears word around the MTC so is not always dead on but never far off.

[mstar]

LH commented they have some thing n the car which is not a easy fix but hopefully they will resolve it "soon" this points to me there is something they have discovered which isn;t easy to fix wonder if this is that exhaust area

[KeiKo403]

Sorry, ignore this

[ringo]

I have a little clarification, just a little thing to fill the time.
The L pods should have a better pressure distribution, and create much less drag, but it doesn't account for some other things.
The L side pod has less down-force compared to the typical designs for some reason, Assuming all have the same coke bottle shape in plan view.

I am not quite sure why, (this sounds cliche) but i think the interaction with the diffuser is the reason behind getting better down force with the other taller side pods.


Looking on the picture, the L side pod in fact has much less drag,and better centre of pressure, due to the distribution, Maybe that's why the car feels good to the drivers?

But looking near the tail of the floor, we can see that the other side pod is creating more pressure on it. This is where most of the force is, and it is compounded by the fact that this is the region above where the lowest pressure is under the floor.

At the front, L side pod has smaller high pressure region, so it help explain the lower drag as well.

I did a few models of different side pod curves. All the same with only a difference with the top surface. The L pod is pretty good for the low drag benefit, because these other designs aren't far away in raw down-force. It's just one design that has a huge difference, i wont say what that curve is

The lift to drag ratio is actually very good. Better than 2 other designs bar the 1 special one. But for raw down force it has slightly less than the 2 typical designs.


The L side pod also has another benefit, it has better flow to the beam wing, ie the velocities are slight higher.


Mclaren's solution is not equally as tight round the back as the others, so it may not see this benefit? but overall i think the L side pod is a good design if they can trim it down.
If it is super refined it wont have the most raw down-force, but it will have the least drag by far.
An taking the beam wing into account it can allow better down-force to be created elsewhere on the car.

this may have to go in another thread for further analysis, but it relates to this car specially.

[Owen.C93]

Very interesting Ringo, thanks.

I'd imagine if they can get the floor exhaust to work then they can slim down the rear a bit.

[N12ck]

May i ask ringo what CAD package you have? and also so basically what you are saying it get the L shape sidepod into a smaller area and mclaren have a pretty good idea with them