FORUMula1.com - F1 Forum

[FerrariFan63]

There's been a lot of discussions about whether the diffusers should be legal or not. But I see very few, if any posts, seem to address the core issue. Which is, whether given a reasonable interpretation of the rules, the diffusers should be legal. Most references to the diffusers seem to boil down to "I like team X who uses the trick diffuser, so it should be legal", or "I like team Y that doesn't use the trick diffuser, so I think they should be banned". More sensible is "Charlie Whiting said the diffusers were OK, so they should be allowed." But Charlie Whiting can get it wrong, or make a decision that's inconsistent with the rules.

Has anyone seen any sophisticated analyses of the trick diffusers that discusses them in the context of the rules? Has anyone read the rules in detail and can make sensible comment? Anybody?

Personally I believe that none of us here have any real idea of whether the diffusers should be legal or not. But I'll post this to see what happens.

Edit: There's this thread over in "the pits", but no real comment on it. viewtopic.php?f=12&t=5250

[Jensonb]

I found this thread pretty useful:

http://www.f1technical.net/forum/viewto ... d1aa94c947

[Jabberwocky]

3.10 Bodywork behind the rear wheel centre line :
3.5 Width behind the rear wheel centre line :
3.5.1 The width of bodywork behind the rear wheel centre line and less than 200mm above the reference plane
must not exceed 1000mm.
3.5.2 The width of bodywork behind the rear wheel centre line and more than 200mm above the reference plane
must not exceed 750mm.

3.9 Bodywork between the rear wheels :
3.9.1 No bodywork situated between 50mm and 330mm forward of the rear wheel centre line, and which is more
than 75mm from the car centre line, may be more than 600mm above the reference plane.
3.9.2 No bodywork situated between 50mm forward of the rear wheel centre line and 150mm behind the rear
wheel centre line, and which is between 75mm and 355mm from the car centre line, may be located
between 400mm and 730mm above the reference plane.

3.10.1 Any bodywork more than 150mm behind the rear wheel centre line which is between 200mm and 730mm
above the reference plane, and between 75mm and 355mm from the car centre line, must lie in an area
when viewed from the side of the car that is situated between 150mm and 350mm behind the rear wheel
centre line and between 300mm and 400mm above the reference plane. When viewed from the side of the
car no longitudinal cross section may have more than one section in this area.
3.10.2 Any bodywork behind a point lying 50mm forward of the rear wheel centre line which is more than 730mm
above the reference plane, and between 75mm and 355mm from the car centre line, must lie in an area
when viewed from the side of the car that is situated between the rear wheel centre line and a point
350mm behind it. When viewed from the side of the car, no longitudinal cross section may have more than
two closed sections in this area.
Furthermore, the distance between adjacent sections at any longitudinal plane must not exceed 15mm at
their closest position.
3.10.3 In order to ensure that the relationship between these two sections cannot change whilst the car is in
motion they must be bridged by means of rigid impervious supports (including any adjustment mechanism)
arranged such that no part of the trailing edge of the forward section may be more than 200mm laterally
from a support. These rigid supports must :
- fully enclose the two complete sections such that their inner profile matches that of the two
sections. Their outer profile must be offset from the inner profile by between 8mm and 30mm and
may not incorporate any radius smaller than 10mm (‘gurney’ type trim tabs may however be fitted
between the supports) ;
- not be recessed into the wing profiles (where a recess is defined as a reduction in section at a rate
greater than 45° with respect to a lateral axis) ;
- be arranged so that any curvature occurs only in a horizontal plane ;
2009 F1 Technical Regulations 11 of 67 17 March 2009
- be between 2mm and 3mm thick ;
- be rigidly fixed to the two sections. Some form of adjustment mechanism between the sections may
be incorporated for the sole purpose of allowing adjustment of the sections relative to one another
whilst the car is in the pits ;
- be constructed from a material with modulus greater than 50GPa.
These supports will be ignored when assessing whether the car is in compliance with Articles 3.6, 3.9.2,
3.10.1, 3.10.2, 3.10.4 and 3.10.6.
3.10.4 No part of the car between 75mm and 355mm from the car centre line may be more than 350mm behind
the rear wheel centre line.
3.10.5 Any parts of the car less than 75mm from the car centre line and more than 500mm behind the rear wheel
centre line must be situated between 200mm and 400mm above the reference plane.
3.10.6 No part of the car less than 75mm from the car centre line and more than 350mm behind the rear wheel
centre line may be more than 400mm above the reference plane.
3.10.7 No part of the car more than 375mm from the car centre line may be more than 350mm behind the rear
wheel centre line.
3.10.8 In side view, the projected area of any bodywork lying between 300mm and 950mm above the reference
plane and between the rear wheel centre line and a point 600mm behind it must be greater than
330000mm².

Good idea for a thread Thought the regs could be helpful

[FerrariFan63]

I found this thread pretty useful:

http://www.f1technical.net/forum/viewto ... d1aa94c947

Still reading it, but it seems very useful. It seems the "problem" (if any) is not the second deck of the trick diffusers themselves, but the holes necessary to feed air into them. With the crucial bit (if I've got this right) being whether you can see bodywork from the bottom that is more than the 175mm limit. Surely if you can see bodywork you shouldn't, the scruitineers would have noticed this during the first two races.

But it's certainly complex, and I don't think the question can be answered without direct access to the cars and a fair amount of equipment.

[Denthúl]

I found this thread pretty useful:

http://www.f1technical.net/forum/viewto ... d1aa94c947

Still reading it, but it seems very useful. It seems the "problem" (if any) is not the second deck of the trick diffusers themselves, but the holes necessary to feed air into them. With the crucial bit (if I've got this right) being whether you can see bodywork from the bottom that is more than the 175mm limit. Surely if you can see bodywork you shouldn't, the scruitineers would have noticed this during the first two races.

But it's certainly complex, and I don't think the question can be answered without direct access to the cars and a fair amount of equipment.

I attempted to draw out various sections of the diffusers to see if they were or were not legal. What I drew seemed to fit in with the regulations, but of course without knowing exact dimensions of the cars or having a perfect view of the underside to work from, they could be way-off. I'd love to get a look at them, personally, as I'm fascinated by how they've managed to slip this design through.

[Jabberwocky]

in that case I will add

3.12 Bodywork facing the ground :
3.12.1 All sprung parts of the car situated from 330mm behind the front wheel centre line to the rear wheel centre
line, and which are visible from underneath, must form surfaces which lie on one of two parallel planes, the
reference plane or the step plane. This does not apply to any parts of rear view mirrors which are visible,
provided each of these areas does not exceed 12000mm² when projected to a horizontal plane above the
car, or to any parts of the panels referred to in Article 15.4.7.
The step plane must be 50mm above the reference plane.
3.12.2 Additionally, the surface formed by all parts lying on the reference plane must :
- extend from a point lying 330mm behind the front wheel centre line to the centre line of the rear
wheels ;
- have minimum and maximum widths of 300mm and 500mm respectively ;
- be symmetrical about the centre line of the car ;
- have a 50mm radius (+/-2mm) on each front corner when viewed from directly beneath the car, this
being applied after the surface has been defined.
3.12.3 The surface lying on the reference plane must be joined around its periphery to the surfaces lying on the
step plane by a vertical transition. If there is no surface visible on the step plane vertically above any point
around the periphery of the reference plane, this transition is not necessary.
3.12.4 The peripheries of the surfaces lying on the reference and step planes may be curved upwards with
maximum radii of 25mm and 50mm respectively. Where the vertical transition meets the surfaces on the
step plane a radius, no greater than 25mm, is permitted.
A radius in this context will be considered as an arc applied perpendicular to the periphery and tangential
to both surfaces.
The surface lying on the reference plane, the surfaces lying on the step plane, the vertical transitions
between them and any surfaces rearward of the surfaces lying on the reference or step planes, must first
be fully defined before any radius can be applied or the skid block fitted. Any radius applied is still
considered part of the relevant surface.
3.12.5 All parts lying on the reference and step planes, in addition to the transition between the two planes, must
produce uniform, solid, hard, continuous, rigid (no degree of freedom in relation to the body/chassis unit),
impervious surfaces under all circumstances.
Fully enclosed holes are permitted in the surfaces lying on the reference and step planes provided no part
of the car is visible through them when viewed from directly below. This does not apply to any parts of rear
view mirrors which are visible, provided each of these areas does not exceed 12000mm² when projected to
a horizontal plane above the car, or to any parts of the panels referred to in Article 15.4.7.
3.12.6 To help overcome any possible manufacturing problems, and not to permit any design which may
contravene any part of these regulations, dimensional tolerances are permitted on bodywork situated
between a point lying 330mm behind the front wheel centre line and the rear wheel centre line. A vertical
tolerance of +/- 5mm is permissible across the surfaces lying on the reference and step planes and a
horizontal tolerance of 5mm is permitted when assessing whether a surface is visible from beneath the car.
3.12.7 No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a
point 350mm rearward of it may be more than 175mm above the reference plane. Any intersection of the
surfaces in this area with a lateral or longitudinal vertical plane should form one continuous line which is
visible from beneath the car. A single break in the surface is permitted solely to allow the minimum
required access for the device referred to in Article 5.15.
Additionally, any bodywork in this area must produce uniform, solid, hard, continuous, rigid (no degree of
freedom in relation to the body/chassis unit), impervious surfaces under all circumstances.
2009 F1 Technical Regulations 13 of 67 17 March 2009
3.12.8 All sprung parts of the car situated behind the rear wheel centre line, which are visible from underneath
and are more than 250mm from the centre line of the car, must be at least 50mm above the reference
plane.

[kerc]

* Head explodes *

[FerrariFan63]

All the teams seem to have rear crash structures that are visible from underneath the car. It's just that some of these teams have made the underside of the crash structure into part of the diffuser. Sortof.

This is very complicated.

[bmwpower]

Everything is legal until it is declared illegal. In every motorsport in the world, every single team will push the rules and find loopholes to make their cars faster, its been done for ages, its just some teams find the loopholes better then others.

[Jabberwocky]

3.9.2 No bodywork situated between 50mm forward of the rear wheel centre line and 150mm behind the rear
wheel centre line, and which is between 75mm and 355mm from the car centre line, may be located
between 400mm and 730mm above the reference plane.

3.10.1 Any bodywork more than 150mm behind the rear wheel centre line which is between 200mm and 730mm
above the reference plane, and between 75mm and 355mm from the car centre line, must lie in an area
when viewed from the side of the car that is situated between 150mm and 350mm behind the rear wheel
centre line and between 300mm and 400mm above the reference plane. When viewed from the side of the
car no longitudinal cross section may have more than one section in this area.
3.10.4 No part of the car between 75mm and 355mm from the car centre line may be more than 350mm behind
the rear wheel centre line.
3.10.5 Any parts of the car less than 75mm from the car centre line and more than 500mm behind the rear wheel
centre line must be situated between 200mm and 400mm above the reference plane.
3.10.6 No part of the car less than 75mm from the car centre line and more than 350mm behind the rear wheel
centre line may be more than 400mm above the reference plane.
3.10.7 No part of the car more than 375mm from the car centre line may be more than 350mm behind the rear
wheel centre line.

think these are the only ones that are included in the query.. look at the underneath ones now

[Jabberwocky]

in that case I will add

3.12.3 The surface lying on the reference plane must be joined around its periphery to the surfaces lying on the
step plane by a vertical transition. If there is no surface visible on the step plane vertically above any point
around the periphery of the reference plane, this transition is not necessary.
3.12.5 All parts lying on the reference and step planes, in addition to the transition between the two planes, must
produce uniform, solid, hard, continuous, rigid (no degree of freedom in relation to the body/chassis unit),
impervious surfaces under all circumstances.
Fully enclosed holes are permitted in the surfaces lying on the reference and step planes provided no part
of the car is visible through them when viewed from directly below. This does not apply to any parts of rear
view mirrors which are visible, provided each of these areas does not exceed 12000mm² when projected to
a horizontal plane above the car, or to any parts of the panels referred to in Article 15.4.7.
3.12.7 No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a
point 350mm rearward of it may be more than 175mm above the reference plane. Any intersection of the
surfaces in this area with a lateral or longitudinal vertical plane should form one continuous line which is
visible from beneath the car. A single break in the surface is permitted solely to allow the minimum
required access for the device referred to in Article 5.15.
3.12.8 All sprung parts of the car situated behind the rear wheel centre line, which are visible from underneath
and are more than 250mm from the centre line of the car, must be at least 50mm above the reference
plane.

[Jabberwocky]

I would imagine from reading them that there is 2 ways around the rulings

a, the diffuser you can see underneath the back of the car is less than the permitted allowance of seen body work

b, the permitted allowance is further forward and a covering plate covers the whole of the bottom of the diffuser

[Mr Sifter]

What is the probability that this FIA hearing is going to go against Brawn GP, Toyota and Williams? I know they souldn't be deemed illegal, but the FIA's erratic attitude makes me think otherwise. If it goes against the diffuser teams and favours those idiots such as Briatore and Ferrari, then I will be really REALLY peeved. If it goes against the diffuser teams, then this will be one of the biggest farces ever.

[bmwpower]

viewtopic.php?f=12&t=5768
viewtopic.php?f=2&t=5746
and a thousand other threads covering this topic.

[FerrariFan63]

http://www.autosport.com/news/report.php/id/74409

Rory Byrne's interpretation of the situation. He claims that the Brawn cars have holes through which parts of the car can be seen. Brawn (team) claim that these re slots, and therefore not governed by the rules that control fully enclosed holes.