McLaren MP4-26 Mercedes

[zgred]

And what about the thing behind it, also visible here, apparently with some instrumentation attached to it:

This thing is IMHO box is measuring pressure from the sensor measch near the tire.

[Formula None]

Have a look at the floor near the rear tires. Note the change in the thickness of the floor and the change in the floor's upper surface angle when the u-bend exhaust is not present vs when it is present. Also, note the discoloration of the unpainted composite panels in the areas I am focusing on (due to heat). Also, notice the ridge running longitudinally and parallel to the edge of the floor. I believe this is open on the side facing the car's centerline and acts as the exhaust exit.



The net effect of blowing the exhaust gases over the floor toward the rear & center of the car would be increased flow around the sidepods and in front of the rear tires. Essentially, more air over the diffuser and beam wing.

[wesley123]

Wow great spot, I am quite sure the exhaust exit there, look at the colour/effects of the panel, they clearly are heated.

[murtoidf1]

Thats a cool post and all, but I mentioned that a page or two back.

and Scarbs himself also mentioned that about a week ago.

nothing new

[Formula None]

Thats a cool post and all, but I mentioned that a page or two back.

and Scarbs himself also mentioned that about a week ago.

nothing new

At least provide a quote of your post you're referring to. I looked through your post history for you, though, is this it?

Nice clear shot showing that it's definitely not an exhaust and looks like it's just a fin controlling air flow or more likely just a panel that happened to catch the light.

First thing Id have to ask is, when was that picture taken? To work this out we'd need pictures all taken during the same run, because mclaren are swapping bits off that car all day.. What you see in one picture isnt necessarily in the other at all, like the exhausts for example.

One thing that is interesting is the slight bulge/ramp in the floor just below the side pod when there V in Vodafone finishes. Scrabs says this bulge is due to the exhaust folding back...

No mention of an inward facing exhaust slit.

Scarbs' post (again, no mention of an inward facing exhaust slit):

http://scarbsf1.wordpress.com/2011/02/17/mclaren-mp4-26-exhaust-is-the-u-bend-a-front-exit/

I don't mean to sound bitchy, but if your going to call plagiarism or say I'm slow, at least back it up with something.

[murtoidf1]

Thats a cool post and all, but I mentioned that a page or two back.

and Scarbs himself also mentioned that about a week ago.

nothing new

http://scarbsf1.wordpress.com/2011/02/17/mclaren-mp4-26-exhaust-is-the-u-bend-a-front-exit/

I don't mean to sound bitchy, but if your going to call plagiarism or say I'm slow, at least back it up with something.

Oh no, im not accusing you of plagiarism or anything like that!

Me, everyone here, and probably yourself has been watching this thread day in day out for some sort of break through in regards to the exhaust. therefore when seeing your posts with no new evidence, I was slightly disappointed!

I didn't see your post as plagiarism at all! Simple more of a recap then anything new - which is what im sure we are all waiting for here.

[Formula None]

Another illustration of the idea:



Using the wheel diameter (358mm +/- 1mm) as a reference I estimate an outlet size of approximately 300mm x 10mm for an exit area of around 3000mm^2, similar to the area of a round 60mm diameter exhaust (which is roughly what an F1 exhaust diameter is, I think). That's my interpretation at least. Could be wrong but this explains the bulge and the the seeming lack of an obvious exhaust exit.

[Tomba]

That picture with the studs along the side looks quite promising. as we know thats how most heat proof stuff is attached to the floor. so there's something def hot there..

Only thing is. in your last diagram the slit is shown to be quite large, but in the other diagrams such as

http://img146.imageshack.us/img146/5378 ... detail.jpg

it looks a bit smaller, surely too small for all the gas to exit ?

[Formula None]

I just edited my previous post, murtoid, to add a size estimate for the slit. Its pretty long, approx 300 x 10 so the area of the exit would not be insignificant.

[Chalke]

Interesting concept from F-None, I have to admit it's the most convincing I've seen yet, as atleast it's not chasing shadows and sensors in blurry pics, the feature is plain to see.

You can see the reverse, or 'exit' of this slit in the pictures we examined last night - http://www.flickr.com/photos/f1photos/5456944194/sizes/o/in/photostream/ - look immediately above the tape on the left hand side of the diffusor as we look at it, and you're staring down the throat of it. I'd like to Pshop it but the licence from flickr doesn't allow that.

This could explain the stickers on the uprights as the hot exhaust air would certainly flow in that area. In my eyes, it also has merit for drawing air inwards around the relatively shallow undercut sidepods, to both reduce drag on the rear wheels and feeding the top of the diffuser/beam wing with more air for downforce. Presumably the slit would also be better at keeping the air 'low' and not spewing in all directions as typical exhaust 'pipe' might.

Edit *Just re-read and realsed my last paragraph is very similar to the text on F-Nones second drawing, accidental i assure you, maybe we just came to the same conclusions*

[Predator]

Those are some great pics. I think you're definitely onto something there, F-None. It looks as if they're doing the same as RB, hence those visible studs around the slots you mention. RB have quite flat outlets similar to ones you have shown and they quickly change between different layouts, so maybe this is it? Can I ask where you sourced your photos?

[JB2011]

Wow that's great!

One thing, couldn't that be done without the U bend? Red Bull seem to have got their pipes down into that area without such an elaborate set up. But is that because their car is longer?

[murtoidf1]

Wow that's great!

One thing, couldn't that be done without the U bend? Red Bull seem to have got their pipes down into that area without such an elaborate set up. But is that because their car is longer?

I agree with this..

Hopefully this theory can be proved right or wrong tomorrow with more pictures.

[Chalke]

Reasons for needing the 'u-bend' that spring to my mind would be

1.Simple packaging constraints caused be the unusual shaped sidepods themselves, the manifold itself could impede a direct path to this area.
2.More exhaust length is needed to convert the round pipe at the manifolds to the slot-shape at the exit, a sharp change in the exhaust pipe could limit airflow?
3.It prepares the air somehow, my knowledge of fluid dynamics is little to none, but could the u-bend even be a spiral to 'slingshot' the air to either increase speed or shape the airflow?

Slinging mud here and seeing what sticks

Re: Red bull, I think the concept for what Mclaren are doing with the air here is very different, RedBull are taking a direct path the blow the outside edges of the diffuser, whereas Mclaren seems to be trying to use the exhuast to draw more air in and over the top edge of the difuser and away from the rear tyre.

[feynman]

The Red Bull is shorter though. No??? Pretty sure it is.

The U-bend is surely just for testing purposes, the engine keeps the same bunch of bananas manifolded onto it, and they just swap out collector pipes and floor panels ... one goes straight out the back, and one loops round and comes out christ knows where.

They are already losing a lot of time on switch-overs (and parts failures and hydraulic failures, and lack of spares) ... so anything that can make the A/B runs quicker, surely.

There was talk of four different configurations, once they pick one, I'm sure the pipe will be optimized for that particular layout.