[WEC] Porsche Prototype Discussion

[deltawing]

Originally Posted by Richard Casto

..... I can imagine that at low speed, such as lower speed corners, it helps the efficiency of the diffuser to create downforce. At high speeds, the trailing edge is pushed down and it likely reduces the efficiency of the diffuser as well as reduces drag when it is needed on long straights. Basically some type of passive DRS. I absolutely believe it was designed to flex....

Elegant Gurney when needed

[Spyderman]

Testing today on the Bugatti circuit:
http://www.endurance-info.com/fr/aud...rcuit-bugatti/

[MyNameIsNigel]

Originally Posted by Richard Casto

MyNameIsNigel posted this link about four days ago in the LMP Future Regulations thread...

http://www.fia.com/sites/default/fil...D0017-LMP1.pdf

Which shows an effort at trying to address a specific problem area (That document appears to be focused on front and rear wings). But it still leaves other parts of the body in the grey area due to a lack of testing procedures.

In my mind the new rear cover of the 919 is playing in that grey area. While no team is going to outright say "this is designed to flex at speed", check out the photos at the bottom of the RE article. Particularly those that show the unloaded/static position and aero loaded/dynamic position...

http://www.racecar-engineering.com/n...ed-at-le-mans/

IMHO there is basically no "grey area" as far as the prohibition of movable bodywork elements or parts is concerned. Articles 3 and 3.4 of the Technical Regulations are pretty clear:

Article 3
The FIA reserves the right to introduce load/deflection tests on any part of the bodywork which appears to be (or is suspected of), moving whilst the car is in motion.

Among other criteria, the FIA will consider the linearity of the
load/deflection curve over the elastic deformation area.
Any non-linearity must be only on the plastic deformation
area.
(...)

Article 3.4
(...)
Movable bodywork parts/elements are forbidden when the
car is in motion.
(...)

Now, Porsche seem to have undertaken last-minute revisions to the rear bodywork and it could be that these were not the final iterations. There are some "curious" differences between the different pictures posted by RCE. In the following two pictures, you can clearly see some support member on the right-hand side of the breather pipe:



This support member is not visible in the picture taken at speed:


So it could be that Porsche were simply trying new things on the cars that were not final.

[Richard C]

Originally Posted by Richard Casto

I expect that the rules are vaguely written on purpose so that they can figure out the details of how to enforce as they go.

Article 3
The FIA reserves the right to introduce load/deflection tests on any part of the bodywork which appears to be (or is suspected of), moving whilst the car is in motion.

I think the above pretty much gets at the core of my quote above. They know they can't define specifics (such as testing procedures) for all conceivable scenarios. I think it is obvious, but we all have to agree that the cars are not made from some type of mythical material that has an infinite elastic modulus. Clearly the intent or dare I say it "spirit of the rules" is to "not move within reason." But I also understand why the rules can't be worded as such. Don't give them an inch as they will take a mile. Start from absolute zero and then allow an inch.

Originally Posted by MyNameIsNigel

IMHO there is basically no "grey area" as far as the prohibition of movable bodywork elements or parts is concerned.

I agree at least as how it is written. Maybe I didn't speak well above as to what I think the grey area is. I think is the grey area is the space between "absolute" adherence to the rules (that are physically impossible to achieve) and a reasonable application of the same rule (in which some movement is allowed/ignored). My comment above about "I can't define excessive flex, but I know it when I see it!" is clearly how this works. When it becomes (or is perceived as) a problem, then the governing body jumps in and uses their catch all rule to define testing procedures and excludes or approves a design.

Even the recent ruling regarding the movement of the front wing area by all teams speaks to this point. They know the teams are doing it for a reason (ostensibly to prevent damage to the cars via curbs or off track excursions), but they also gave some wiggle room regarding how much flex is allow beyond the normal amount that they expect to see. Typically any time testing procedures are put in place to test for movement, they never have a zero tolerance procedure (i.e. absolutely zero movement). It typically is X amount of force can result in Y amount of movement.

Originally Posted by MyNameIsNigel

So it could be that Porsche were simply trying new things on the cars that were not final.

It could be. I could be wrong. I am not a mechanical engineer (electrical by training), but by looking at that design, I don't see something engineered to prevent flex, in fact, I see the opposite. Even if that extra piece that is missing in the "flex photo" is to prevent flex, it is a poor solution for that. Maybe... they just screwed up as well. Maybe they thought it would be fine and it didn't work.

Regardless, I am not supporting contravention of the rules. But I do support playing in the grey areas as unfortunately these days that typically is where the speed is found.

Richard

[MyNameIsNigel]

As a matter of fact, one may wonder if the trailing edge of the rear bodywork wasn't "flexing" at speed already in their previous iteration, at least to a certain extent. In this previous "studio" shot (I believe this is the "test spec" as exhibited in Geneva last March), you could at least identify a supporting surface under the "engine cover":

[MyNameIsNigel]

Today @LM. Hmmm...

(source: endurance-info.com)

[Articus]

1) A toe back to the pits
2) By a Fire Safety Truck...

3) the ridiculousness of this picture. The VW Amarok is an Audi Safety Truck towing a Porsche.

[Spyderman]

Originally Posted by MyNameIsNigel

Today @LM. Hmmm...

(source: endurance-info.com)

I get very nervous when I see photos such as this one.

[gwyllion]

Perhaps they just ran the tank dry

[MyNameIsNigel]

Originally Posted by gwyllion

Perhaps they just ran the tank dry

Who knows ?

But they did have to work or fix something...

[wewantourdarbyback]

Originally Posted by MyNameIsNigel

This support member is not visible in the picture taken at speed:


So it could be that Porsche were simply trying new things on the cars that were not final.

Hmm, that crop gives the impression that the main rear deck, just to the side of the pipe, has flexed downwards towards the diffuser to the point it is almost touching.

The top two pix show that there is a panel gap at the exact place where it seems to have flexed down.

Of course there could be any other reason.

[Spyderman]

nice interview: http://www.speedchills.com/home/spee...up-to-le-mans-

[vincegail]

Originally Posted by Spyderman

nice interview: http://www.speedchills.com/home/spee...up-to-le-mans-

"Webber, fresh from a small job in the PR department of an energy drinks company, has finally made it back to the big leagues."

[jimclark]

Originally Posted by vincegail

"Webber, fresh from a small job in the PR department of an energy drinks company, has finally made it back to the big leagues."

'Just curious... What's so funny???

[Articus]

Originally Posted by jimclark

'Just curious... What's so funny???

I see what you did there?

[jimclark]

Originally Posted by Articus

I see what you did there?

Now I'm totally lost. Is that a statement or a question?
In either case, I don't understand it. I asked a question...what else was I supposedly doing???

[Articus]

Originally Posted by jimclark

Now I'm totally lost. Is that a statement or a question?
In either case, I don't understand it. I asked a question...what else was I supposedly doing???

ahh ok! So the joke is that Webber's F1 stint at Red Bull was merely a small public relations job at some fizzy drinks company and that return to Porsche and Le Mans is the major leagues.

[skeeskirrt]

Originally Posted by Articus

1) A toe back to the pits
2) By a Fire Safety Truck...

3) the ridiculousness of this picture. The VW Amarok is an Audi Safety Truck towing a Porsche.

Should have been a Toyota truck.

[gwyllion]

Originally Posted by gwyllion

The May 2014 edition of Racecar Engineering has an article on the 919: http://gb.zinio.com/reader.jsp?issn=0961-1096&o=ext&p=8

The following explanation is given why they went for coil springs:

The July issue of Racecar Engineering briefly discusses the interlinked suspension.

Porsche has developed what is considered to be a trick suspension system. It attempted to patent the system in Korea, but the patent was rejected. Unfortunately our Korean is not sufficient to work out why the application failed. "This looks like a self-levelling system to me," says our technical consultant Peter Wright. "The description seems to indicated that the levelling cylinder is in series with a spring, which connects to each end of the ARB. The suspension seems to meet the regulations, provided it has fixed characteristics." At the Spa 6 hours, Porsche had a rear damper failure, yet was able to change it quickly. "Changing a connected actuator is quite an issue, as the volume of hydraulic oil in the connecting hoses is critical," says Wright. "Also, any air in the system would affect it."

[gwyllion]

In case people are interested, there are some good technical articles about interlinked suspensions that are currently used in F1.
http://scarbsf1.com/blog1/2011/10/17...ar-suspension/
http://somersf1.blogspot.com/2013/04...edes-fric.html

[The Badger]

Good ..... finding out the issues before the race , I wouldnt expect anything else .

[Spyderman]

One of the jobs still available for the LMP1 project at Porsche is Head of Suspension

http://content2.eu.porsche.com/prod/...sach&fulltext=

[Articus]

I don't think the issue is "rapid turnover" or the like. It's possible that the engineers are hired on short term contracts rather than permanent positions. So Porsche is always looking for new applicants. If they think a current employee is less than satisfactory, he can be replaced. Porsche most likely has a current 'head of suspension"

[Richard C]

Originally Posted by Articus

I don't think the issue is "rapid turnover" or the like. It's possible that the engineers are hired on short term contracts rather than permanent positions. So Porsche is always looking for new applicants. If they think a current employee is less than satisfactory, he can be replaced. Porsche most likely has a current 'head of suspension"

I would agree. That current "head of suspension" might be a technical leader, but just a placeholder (maybe not a suspension expert) until they can get someone to fill the position. There might have a bit of "design by committee" in some places until they get really strong people in place. Also, I think I read that one thing they plan to focus on for next years car was suspension.

I don't know how many people work in that area (how large of pool they can pull from), but I read the position requirements and they seemed tough for me. Extensive suspension design experience with LMP or F1 plus fluent in German and English. It almost seems targeted at Audi!

Richard

[Breitling24]

So, they might have suspended the "head of suspension"? The suspense is killing me!