McLaren MP4-26 Mercedes

[feynman]

I'm sorry. But they are optical illusions. The last one is easily provable if you just zoom in. You can see one of the vanes between the slits on the end plate. But here, I made a picture for you, actually showing it.

Could be, but I think it's a stretch, not entirely convinced.

This alternate image was done quickly and judged by eyeball, so I'll admit to plenty of room for error ... but not sure there is anything like enough error to make the blue region stretch to where it would have to stretch.


Cars are mirror imaged, if you are desperately short of track time, and short of reliability, for some aero testing it makes sense to run two discrete configurations at once and effectively double your mileage.

[Just_a_fan]

if you are desperately short of track time, and short of reliability, for some aero testing it makes sense to run two discrete configurations at once and effectively double your mileage.

And how do you separate the results / effects of one side from the other? The airflow from each side of the car will have an effect on the other.

McLaren ran asymmetric exhaust pods in the past and now people seem to be looking for reasons why an optical illusion (or even a simple mistake on the part of the viewer) means they're running asymmetric aero configurations.

Presuambly some adults still believe in Santa Claus and the tooth fairy...

[feynman]

Depending on what you are measuring, the results/loads/deflections/velocities can very often be reasonably isolated.

Where they can't, it may be possible to construct a carefully designed matrix of cross-comparison runs and employ statistical analysis to deduce significant factors and parameters from your experiments.

Yes they would obviously prefer hundreds of discrete isolated test-runs, but if the car can't do the distances without cooking and snapping, then you need to get creative and sometimes you'll have to take what you can get.

Nothing to do the tooth fairies, rather, it's science.


No-one here is saying anything for definite, they are just looking at photos and talking about them.
I thought that was kinda the point of this place.

[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?

[speedsense]

When judging/measuring aero influence through a data acquisition system, most software programs have "gating". Gating is where certain conditions are set and have to exist to take a measurement. For instance in measuring wing balance front to rear, you would gate the software to measure the car at a certain speed, straight ahead (no lateral g), steering at 0, and measure the difference of movement from a static point (setup table) and take measurements all at the same gated space and time, A)laser ride height sensors (front and rear) B) suspension sensor (ride change) C)pushrod load cell for wheel loadings.
The gating "clips" this information from the full lap and brings the measurement across a few hundred samples (of say 500 samples per second for suspension/ride height sensors) when the conditions are met to full fill the software argument created.

The same gating can be done (at the same time) side to side to measure downforce (tilt) and diagonal (warp)....all you need is a straightaway, the right speed and a car stable enough to go straight....

So dividing the car can be done front to rear, side to side and cross wise and the answer found in one straight away that the conditions are met.

Santa Claus's sled can be measured the same way as even bobsleds are using data acquisition, why do you think Santa is so quick to get around the world? It's those load cells on the runners, HO HO HO

[forty-two]

Thanks for the explanation Speedsense. I think you're right there.

But just one question.... what is a "straightaway"?

[speedsense]

Thanks for the explanation Speedsense. I think you're right there.

But just one question.... what is a "straightaway"?

The drag race between corners

[forty-two]

So, a Straight then?

Sorry, I'm really not being pedantic, I've just not heard it called a straightaway before. To me, straight away is an indication of when something will happen, i.e. immediately.

Perhaps it's a regional thing?

Sorry for being off topic people!

[ringo]

3 pages on the symetry of the car. Kind of trivial, maybe it is
asymetrical, maybe it's not? doesn't change the fact that the car is slow and needs a major overhaul to even sniff the redbull.

The car needs to be disposed of and a new 26 built.

I don't know if the mclaren guys were aiming at being unique more than they were aiming at being the quickest.

The car is so different and not in the good way that allows it to work properly.

High crash structure for whatever reason. As if they originally wanted to use that volume under it for some reason.
But alas it cannot work anyway because the side pods choke up the volume upstream of it.
High crash structure fused into the beam wing showing that they have less regard for the beam wing than the top of the diffuser, which seems to be the wrong philosophy for 2011.
Too many quirks on the car to list.

There needs to be a shake up at mclaren. These guys are more into building fantasy toys with neat little details, that don't synthesize with the whole car, than championship winning cars.

3 years in a row now.

I think the car can be corrected, but the time taken to do that doesn't help them.

The question of whether the crash structures can be changed, anyone has a definite answer?

[Just_a_fan]

Yeah, straightaway is what USians call straights. It is, as you say, a regional thing.

[Just_a_fan]

When judging/measuring aero influence through a data acquisition system, most software programs have "gating". [...]

Ok, a fair description. Not sure it's what McLaren are doing though.

[feynman]

...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.

Can we just get a baseline here, do we think there are some diffuser vanes not roughly where we'd expect them in that particular photo. Now maybe they fell off, or got left on a kerb, or maybe they melted, or maybe it's by design for accelerated testing.

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.

[speedsense]

So, a Straight then?

Sorry, I'm really not being pedantic, I've just not heard it called a straightaway before. To me, straight away is an indication of when something will happen, i.e. immediately.

Perhaps it's a regional thing?

Sorry for being off topic people!

Yep, us Americuns sure talk funny. Funny thing is I born in England, my parents are Scottish, but I grew up here.

So straight it is...straight back to the thread....

[myurr]

...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.

Can we just get a baseline here, do we think there are some diffuser vanes not roughly where we'd expect them in that particular photo. Now maybe they fell off, or got left on a kerb, or maybe they melted, or maybe it's by design for accelerated testing.

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.

If you can compare your image against the image at the very top of the page where you can see all 4 vanes in the diffuser, I do not think you have correctly measured the distances to the 'missing' vane. I'll take a look later this evening and see if I can come up with a better picture.

I am convinced that the front wing has been symmetrical in all the pictures posted so far. In the diffuser it's clear to me that 3 of the 4 vanes are visible, it's just a case of whether the fourth vane is hiding behind the rear wing or not.

[feynman]

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)

I am not sure if asked I would have guessed quite that high for that rear-face, although it makes sense. It's still kinda on the high-end though, as the MES spec for the rain-light describes a max operating and storage temperature of 85°C for the unit.

Of course, a few extra degrees never hurt anyone, but again just as another indication of precisely how close to the car's thermal limits they are all pushing things.