Underfloor of Mclaren F1

[zx4000]

A few months ago, i handled this thread and at that time below pic was supplied by drew. However another question ocurred to me all of sudden.
Was this carbon-fibre skirt fitted by Mclaren cars or Turnermotorsport?
Because this one is so flat and could never seen it's waviness(means that never considered in a aspect of aerodynamic). If Gordon Murry had made this, would have been molded for possibly the groove of bolts.i am sure that Possibly Drew can clarify this things.

[Mr. Bernoulli]

Nope, that's how it comes. The undertray is much flatter on the cars with the HDK fitted I believe. The bolts' effect on the airflow is minimal.

[zx4000]

Originally Posted by Mr. Bernoulli

Nope, that's how it comes. The undertray is much flatter on the cars with the HDK fitted I believe. The bolts' effect on the airflow is minimal.

Hi Bernoulli
long time long see.
the molding of bolts are just trivial things as you told me. anyway
Let's turn our attention into entire underside shape.
what i focus on is the shape of underside skirt. . For referance to compare with mclaren's, i'll show you enzo's. the part as it show is the rear connected to disfussor. you can figure easily the difference between two cars'. Mclaren's underside is so flat, plain and smooth.
as you see below, this mid-part between two disfussors hole has a important effect in ground effect. Underneath a fast car, an inverted wing shape in the underskirt can create low pressure in the end since the same volume of air must move past the underneath of the car at each stage, by making the car "fatter" in the middle, you reduce the volume available for the air to move through, and thus force the air to go through this space faster. Faster moving air creates an area of low pressure, so the corresponding higher pressure on top of the car helps to push it down harder, ie the car is "sucked" down at high speeds, and thereby enjoys more downforce and correspondinlgly.

So Even though take into account the generation difference 6 years of both cars, at least Gordon Murray could never have missed those things.
To my personal opinion, i am a littel sure the underside of #003LM must be converted from original one. My claim might be absolutely wrong if someone showed a entire underskirt shape.

[drewwtms]

It was never altered in the hands of Turner Motorsport. And it's closer to 8 years ago - not 6 - that the car was built.

I would assume that the third generation GTRs (1997) that McLaren built had some sort of venturi system underneath. But on a street car how necessary is it... especially with that monster wing on the back? Also remember that McLaren never spent a lot of time in a wind tunnel developing the bodywork on the 1995 GTR (what the LM is based off of).

[maartenvanthek]

FYI, that pic was taken in holland at the AUTOrai, you see the maserati stand behind it. 'Hessing' is also the official importer for lambo, rolls and bentley. And I was a VIP there, imagine! the shots are 13.5 months old! the Enzo didn't impress me much btw, i saw a McLaren soon after, and that was far more convincing

[Peloton25]

Originally Posted by zx4000

So Even though take into account the generation difference 6 years of both cars, at least Gordon Murray could never have missed those things.
To my personal opinion, i am a littel sure the underside of #003LM must be converted from original one. My claim might be absolutely wrong if someone showed a entire underskirt shape.

There aren't any other great photos of the undertray from the LM or GTR that I can think of which show the rear portion. Maybe sometime this year the LM will be better documented on film for all of us to see. I can assure you that no one would ever modify an LM though - their rarity ensures that they will remain stock to preserve their value. Also, I highly doubt that anyone would second guess Murray/McLaren on the undertray aerodynamics if they were planning to modify the car in some way at all.

Here's two shots that show the backside of the undertray on an LM. The first shot is of XP1 LM, the LM prototype:



This second shot shows the back of LM3, which you can see is identical to XP1 LM. I had to up the gamma and brightness to get the diffusers on each side to show up more clearly.



As you can see, it looks like the back portion of the undertray does kick up to create a partial venturi effect. While it doesn't have the channels like are pictured on the Enzo, I'm sure McLaren decided that this design was more effective in combination with the large rear wing which the Enzo lacks.

>8^)
ER

[kfoote]

I believe there are a couple of other factors at work here that have not yet been mentioned.

First, there is a packaging issue where there is not really any good place to put the Enzo-type ground effects package and have it be effective with the BMW engine. The exhaust headers are right where the tunnels would be ideally placed, and there would have to be some rear suspension redesign and relocation of a couple of parts to be really effective.

IIRC, and this is 100% from what I remember and coud be incorrect, the ACO LeMans rules at the dime did not (and still do not) allow venturi tunnels like the Enzo has. It would have resulted in them redesigning the back of the car for the race cars close to what it ended up as.

Third, though the venturi tunnels add downforce, they are increasingly sensitive to angle of airflow, meaning that going around corners lost effective downforce very quickly when the airflow underneath the car is not perfectly aligned with the car. IIRC, in the last generation of CART cars that had ground effects, if the angle of airflow was more than 15 degrees off the nose of the car, the car would basically be totally out of control.

[fastz06]

Originally Posted by maartenvanthek

FYI, that pic was taken in holland at the AUTOrai, you see the maserati stand behind it. 'Hessing' is also the official importer for lambo, rolls and bentley. And I was a VIP there, imagine! the shots are 13.5 months old! the Enzo didn't impress me much btw, i saw a McLaren soon after, and that was far more convincing

theres no maserati. thats an F360 modena.

[Peloton25]

He said "Maserati stand", meaning their display booth. If you look on the wall above the Enzo in the first pic, you can clearly see the Maserati trident logos.

>8^)
ER

[maartenvanthek]

thank you peloton, at the other side of the maserati logo's were the bentley's and the lamborghini's, everyone was hanging on the 'fences' they made, and i was sitting in it, almost got them to start the car, only the floor manager wouldn't let me... shame..

[a5678]

Whats with the distorted opening where the tailpipes come out ?

[Peloton25]

Strange shadows from the lighting is my guess.

>8^)
ER

[a5678]

VERY strange

[mini magic]

it looks like a bad photoshop. look at the far right tailpipe, its not even with the one on the left

[Peloton25]

That photo came from CAR Magazine, so I doubt it's any kind of "photoshop". Also, if you look closely at the other photo I posted, the tailpipes on LM03 aren't exactly lined up either.

>8^)
ER