McLaren MP4-29 Mercedes

[daveyrace]

Gary saying these things will reduce drag?

At higher speed, because of suspension deflection, a gap will open up between the bottom of the lower blocker and the diffuser, which will reduce drag.

Surely removing them all together would decrease drag since there´s nothing in the way for the airflow?
But what do i know, zero.

http://www.autosport.com/news/report.php/id/112341

I think he means that drag is reduced compared to if they didn't open up a gap, still draggy, just a bit less which will help at speed. It reduces the downsides.
The car would be less draggy if they chopped off the front and rear wing, but I am sure they choose to have them there for a reason. Same as all the aero gubbins they used to have strewn about over the cars back in 2008.

[turbof1]

I'll rephrase what has been asked about then: will the L/D ratio be increased at high speed compared to a conventional suspension?

[JDC123]

Gary saying these things will reduce drag?

At higher speed, because of suspension deflection, a gap will open up between the bottom of the lower blocker and the diffuser, which will reduce drag.

Surely removing them all together would decrease drag since there´s nothing in the way for the airflow?
But what do i know, zero.

http://www.autosport.com/news/report.php/id/112341

I think he means reduced drag vs. when there is little downforce on the rear axle, not absolute drag.

The increase in downforce, due to the diffuser working harder must outweigh the drag that comes with it otherwise they wouldn't run with it. Remember noe that exhaust blowing has been band teams will be looking for other solutions to find more rear downforce as the rear is always the limiting factor.

[boson]

Even if the shape of the wishbone makes downforce, they are still wishbones, and therefore not movable aero in my book. The only controversy could be if it is a fairing attached to the wishbone, in which case it is an aero attachment which moves. Otherwise I don't think that it can be classed as illegal unless the reword the ruling to include specific shapes of componants.
The whole car moves up and down on the suspension, and IMO classing suspension parts as movable aero is like classing everything that isn't unsprung mass as movable aero!
Its like the UCI rules for bikes, wheel fairings aren't allowed but you can make the rim whatever shape you want, meaning it can have the same shape as a wheel fairing, so long as it is still a wheel rim.

[Pup]

The FIA has been allowing a lot of extreme rule bending stuff lately; I wouldn't be surprised if they not only allowed it, but gave mclaren a pat on the back on the good job they did.

I think the brake ducting is ample precedent for this. all of those winglets that are allowed these days goes far beyond anything necessary for brake cooling.

I think this will be a case of the specific rule (the one giving dimensions, angles, etc. for the members) overriding the general one (no moveable aero). The specific rules are in essence saying "here's how to make a suspension member that meets the other rules."

question: a substantial change in flow just ahead the diffuser doesn't cause an abrupt change in rear aero load and so an unstable/difficult to drive car ?

I don't think the gaps will change that much, given the geometry and minimal suspension movement.

[juanfran]

Rulebook says:

any specific part of the car influencing its aerodynamic performance :

b) Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c) Must remain immobile in relation to the sprung part of the car

http://www.fia.com/sites/default/files/ ... -12-09.pdf

Article 3.15

Obviously, butterfly arms affect the aerodynamic performance, therefore, they are clearly illegal in my opinion.

[Ferraripilot]

Rulebook says:

any specific part of the car influencing its aerodynamic performance :

b) Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c) Must remain immobile in relation to the sprung part of the car

http://www.fia.com/sites/default/files/ ... -12-09.pdf

Article 3.15

Therefore, butterfly arms are clearly illegal in my opinion.

But they do move,as I understand it anyway, as they are part of the suspension and are clearly for aerodynamic aid.

[Pup]

I think part of how this works is that the air that would have gone over the diffuser is going to be directed up underneath the rear wing. This will be fast, low pressure air and it's going right where you'd want it. Not to mention that this air will be energized by the exhaust.

As for the drag, I'm not sure of its penalty. I mean, the low pressure behind will just be driving more air in the diffuser. I think the question of drag will be more related to how much air can be pulled under the floor, right? In front, the air dam will direct the air coming around the body up and over, so perhaps also not so much of a penalty there.

[Forza]

Jerez T0 1 - Day 2

[Pup]

Rulebook says:

any specific part of the car influencing its aerodynamic performance :

b) Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c) Must remain immobile in relation to the sprung part of the car

http://www.fia.com/sites/default/files/ ... -12-09.pdf

Article 3.15

Obviously, butterfly arms affect the aerodynamic performance, therefore, they are clearly illegal in my opinion.

Yes, but as I said below, I think 10.3 outweighs 3.15. 10.3 is specifically describing a suspension that meets 3.15 (otherwise, the rules would be in conflict). So if your suspension meets 10.3, it should transitively meet 3.15.

[Pup]

By the way - snout aside, this car is quite stunning. It looks the part.

[juanfran]

Rulebook says:

any specific part of the car influencing its aerodynamic performance :

b) Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c) Must remain immobile in relation to the sprung part of the car

http://www.fia.com/sites/default/files/ ... -12-09.pdf

Article 3.15

Therefore, butterfly arms are clearly illegal in my opinion.

But they do move,as I understand it anyway, as they are part of the suspension and are clearly for aerodynamic aid.

True, but, by their own working principle, these arms will move with the suspension, meaning they are not 'rigidly secured to the sprung part of the car'.

[acosmichippo]

Rulebook says:

any specific part of the car influencing its aerodynamic performance :

b) Must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any degree of freedom).
c) Must remain immobile in relation to the sprung part of the car

http://www.fia.com/sites/default/files/ ... -12-09.pdf

Article 3.15

Therefore, butterfly arms are clearly illegal in my opinion.

But they do move,as I understand it anyway, as they are part of the suspension and are clearly for aerodynamic aid.

problem is *everything* influences aerodynamic performance, including regular wishbones, so I don't think this specific rule is applicable. why do these wishbones "influence aero performance" when others do not? The only way to quantify this is to compare them against the rule that dictates the legal shapes suspension members can be. if mclarens wishbones fit in those parameters, then they should be legal. If FIA still doesn't like it, they'll have to amend that rule.

[turbof1]

I think we can all agree interpretation is key.

The FIA never has used these regulations in a consistent manner. Sometimes they allowed solutions that went against 3.15 based on 10.3, sometimes not. A couple of times the fia even abused 3.15 to ban things. Renault's mass damper comes to mind.

It's tricky to predict how the fia will act. Even if Charlie Whiting says that it's ok, we might see the fia go right against it. I personally feel they'll allow it because there's a shitload of rulebending this year in all kinds of areas: lotus tusks, twisted camera wings, etc. I think the fia will not want to complicate matters further by sorting what they can allow and what not.

[danielk]

all i can say is if that is allowed on the mclaren car (assuming this is a permanent fixture and not just a sensor ) it is taking the rules to the extreme.

Suspension arms do all currently create downforce/aeroneutral. But if this is allowed people will be fashioning the suspension in all sorts of wacky ways! If that is allowed at the back you will soon see some other wacky interpretation on the front suspension. with the suspension arms growing pieces all over the place to generate downforce.