Legality of McLaren's "Butterfly" suspension

[cossie]

I sense Richard is going to move this to its own thread any moment haha.

Why don't you just start a thread then, instead of filling up two pages of this one with this nonsense?

Amen

[Ferraripilot]

I sense Richard is going to move this to its own thread any moment haha.

Why don't you just start a thread then, instead of filling up two pages of this one with this nonsense?

Agree, Richard or other mod, let's please move this when you have a moment. Sorry to clutter up what has been a great thread

[Owen.C93]

So you are trying to tell us that Drag Reduction is no Aerodynamic purpose, but Downforce is an aerodynamic purpose?

As long as it meets the below:

10.1.2 The suspension system must be so arranged that its response results only from changes in
load applied to the wheels.


The above could apply also to Mclaren's case as it could be questioned whether their system alters suspension movement especially in high downforce situations, with the air pressure this essentially blunt object is facing it is possible it alters suspension movement in other ways not controlled from load applied to the wheels.

I thought the main advantage was helping the diffuser flow and not really producing downforce by itself.

[Ferraripilot]

Similar to the Lotus brake cylinder situation, it also didn't create downforce, but it did keep the car more stable under braking thus allowing for a lower static ride height thus aiding downforce in a movable manner.

This is the same as Mclaren's design in a big way, it moves, it clearly affects aero, illegal. Lotus' brake cylinder moved, affected aero, illegal.

[Owen.C93]

Similar to the Lotus brake cylinder situation, it also didn't create downforce, but it did keep the car more stable under braking thus allowing for a lower static ride height thus aiding downforce in a movable manner.

This is the same as Mclaren's design in a big way, it moves, it clearly affects aero, illegal. Lotus' brake cylinder moved, affected aero, illegal.

The lotus system was about controlling the aero surfaces in an unnatural way. Brake ducts move and affect aero, all other surfaces move relative to the unsprung part of the car and affect aero.

I think a good point was raised whereby if you can create the wishbones super thin or use the drive shaft cover to reduce drag, then why can't you make them thicker to create a low pressure zone.

[trinidefender]

Similar to the Lotus brake cylinder situation, it also didn't create downforce, but it did keep the car more stable under braking thus allowing for a lower static ride height thus aiding downforce in a movable manner.

This is the same as Mclaren's design in a big way, it moves, it clearly affects aero, illegal. Lotus' brake cylinder moved, affected aero, illegal.

Ferraripilot please stop bashing on about it. We get it. You think it is illegal. I get the impression that had Ferrari come up with this idea you wouldn't be so quick to say it is illegal.

For this to be illegal then all the suspension arms will have to be illegal. All the aero shaped brake ducts. Passive DRS systems. Coanda exhausts etc etc. what lotus had was different in that by the driver applying the brake he is applying extra pressure to the suspension system and stopping the nose diving. It is directly driver controlled device which is actually defined as being illegal.

[crbassassin]

Pull rod suspension is a suspension system first, that's precisely how it must be mounted first, any aero benefit is 100% secondary. Teams using pull rod suspension could not consciously design it to work any other way than how it currently does. The pull rod is also not designed in some fantastical aerodynamic way either.

Mclaren's rear suspension had I'm sure plenty of options, but they consciously went for an aerodynamically beneficial route first, suspension geometry second, because they clearly could have obtained that specific suspension geometry dozens of other ways. The mushroom arms are just icing on this 'aerodynamic first' cake to kick it out of the park.

Whitmarsh, is this you?

[tok-tokkie]

McLaren were allowed to use the FDuct when the rules banned switchable aero devices. I was surprised because the driver had to cover a hole in an air duct which had the consequence of switching the airflow via the flip-flop in the FDuct. It was permitted by FIA & so all the other teams had to develop their equivalents. It took them time & McLaren had a big advantage. Years later the entire system was banned.

I really agreed with the FIA. McLaren had come up with a good idea & were allowed the benefit before the entire idea was banned. But I was surprised because the interpretation of the rules was quite lenient towards McLaren in that instance.

Now McLaren have come up with a similarly clever idea. This time it seems to comply with the rules much better than the FDuct. This time it is going to be really difficult to retrofit it to existing cars. If it is as effective as is hoped the other teams are going to bleat like hell. I hope McLaren is given the benefit.

RedBull had the exhaust diffuser blowing system jacked & reaped the benefit for some years. Now they seem to be really on the back foot with a serious design problem = overheating of ERS components & no dragonfly.

Poor Whitmarsh. This car was developed during his watch but Dennis is going to reap the benefit. (I think he under performed miserably & deserved to go but sad that this will not be on his credit account.)

[acosmichippo]

It seemed a lot of people preferred having this discussion separate from the main mp4-29 thread, but I haven't seen a separate thread crop up yet, so here it is. Please feel free to delete if deemed redundant.

Anyway, here is the rear suspension in question. I will add more pics as I come across them.



Some have nicknamed it "butterfly" suspension because of its overall shape with the rear crash structure, and some call it "mushroom" suspension due to the side profile of the wishbones.

The technical regulations regarding suspension can be found here on the fia website, but here they are pasted:

10.3 Suspension members

10.3.1

• With the exception of minimal local changes of section for the passage of hydraulic brake lines, electrical wiring and wheel tethers or the attachment of flexures, rod ends and spherical bearings, the cross-sections of each member of every suspension component, when taken normal to a straight line between the inner and outer attachment points, must:
  1. Intersect the straight line between the inner and outer attachment points.
  2. Have a major axis no greater than 100mm.
  3. Have an aspect ratio no greater than 3.5:1.
  4. Have no dimension which exceeds 100mm.
• The major axis will be defined as the largest axis of symmetry of any such cross-section. The length of the intersection of this axis with the cross-section must not be less than 95% of the maximum dimension of the section.

10.3.2

• Suspension members having shared attachment points will be considered by a virtual dissection into discrete members.

10.3.3

• No major axis of a cross section of a suspension member, when assessed in accordance with Article 10.3.1, may subtend an angle greater than 5° to the reference plane when projected onto, and normal to, a vertical plane on the car centre line with the car set to the nominal design ride height.

10.3.4

• Non-structural parts of suspension members are considered bodywork.

10.3.5

• There may be no more than six suspension members connecting each suspension upright to the fully sprung part of the car. Redundant suspension members are not permitted.

10.3.6
[irrelevant wheel tether stuff]

I will post my opinion in a separate comment, and leave this one just for info.

[acosmichippo]

In my opinion, 10.3.1-10.3.3 and 10.3.5 should not be a problem. I'm sure mclaren has fit the suspension members well within these limitations, and there are even rumors that FIA has already looked at it and approved.

The only parts I think *could* give mclaren problems is 10.3.4:

10.3.4
Non-structural parts of suspension members are considered bodywork.

But I'm also sure mclaren is prepared to show that the shape is a structural part of the suspension and not simply a cover, which would qualify it as "bodywork". The only question then is if FIA accepts that explanation.

[feni_remmen]

Definitely legal, but as we've seen before, politics will determine if these are allowed to stay.

[CBeck113]

I am honestly split on this topic, and have added my technical thought to this.

Pros:
*Macca has definitely found a novel way to get the diffusor to work harder without the beam wing (if it works, we still haven't seen the cars go flat-out, I'll explain later in the cons).
*They fulfill the rules to the letter. The best part is the fact that gaps open up to reduce drag when it is not completely needed.
*If it works then the other teams will be months behind if/when they have it on their cars.

Cons:
*"Spirit of the rules" clause could easliy be debated. Macca has prepared for this with the development of a standard suspension, showing that not even they think that it'll be simply accepted.
*The drag reduction by opening gaps during braking (i.e. negative force on the suspension), could also be a problem in fast turns, where you want the diffusor to work the most, because the inside wheel will have negative force - *here a "FRIC" system would have to be tuned for this scenario as well.
* Macca will have to show a mechanical advantage/necessity for this design if challenged - they may have to hire Ross Braun solely for this purpose!
* It is drag in a sensitive area of the car. Turbulent flows due to this could make the car feel nervous, and the changes to the downforce due to suspension movements must be made predictable, or the drivers won't have confidence in their cars.

No idea:
*Will the additional drag be compensated by the theoretical improvement for the diffusor? Its advantage is that it creates downforce without drag...
*The ideas about the aerodynamic influence could be used as evidence against them, as it would be that they remove this suspension for Monza...

And one last point: I feel that no matter what happens, the FIA needs to find a way to be more specific in their rules, since they don't seem to be able to use their "spirit of the rules" clause for anything.

[rjsa]

And one last point: I feel that no matter what happens, the FIA needs to find a way to be more specific in their rules, since they don't seem to be able to use their "spirit of the rules" clause for anything.

It was going well untill here.

FOR GOD's SAKE PLASE NO!

[FW17]

I dint understand Charlie Whiting,

Beam wing banned, Mclaren find a replacement solution for the beam wing, which i guess is legal, but then what is the point of banning the beam wing?

[mclaren_mircea]

Omnicorse confirmed that Red Bull protested Mclaren's rear suspension to the FIA, but the guverning body made it clear that Mclaren's solution is perfeclty legal. I will present the article using (sorry for this ) google translate.

"Red Bull had protested the shutter McLaren
The technicians of the FIA ​​felt perettamente legal solution of the MP4-29.
E 'already war of nerves and stamped papers. Some believe that certain faces with its trunk are dangerous as they have been interpreted regulations and who, instead, is concerned about the new technical solutions. The rear suspension "shutter" of the McLaren MP4-29 is arousing great interest among the technicians.

The Red Bull Racing, indeed, had sent a request for clarification to the FIA regulations stating that the solution could not be linaea with the rules 2014: the technicians of the International Federation, on the other hand, have stated fully in line with the ingenious solution of the MP4-29 , at least for the moment, seems to give excellent outline the track.

http://www.omnicorse.it/magazine/34306/ ... la-mclaren