Audi LMP1 Discussion

[gwyllion]

http://endurance-info.com/version2/a...ance-9867.html has an interview with Fässler. His comments on the hybrid car:

The hybrid system pushes during acceleration and when it stops, you get the impression that something is broken. It's a strange feeling at first, but you get used to it pretty quickly. This is stunning! There is still much work. This is a brand new challenge and the hybrid opens doors for the future in motorsport. We have already started the endurance tests and we are pleased with the result. Everything goes without the slightest hitch, even though we still need time to get ready for Le Mans.

[chernaudi]

When did these tests start--presumably only in the past few weeks between last week (Sebring prep) and the public launch.

However, if the endurance testing is going well, that can only help Audi at LM, as TMG have done only one major endurance test, and they had some minor issues (new car related probably more than anything else).

I'm wondering if any F1 drivers felt the same as Marcel did when their KERS ran out and needed to be recharged. Maybe in that way Seb will fit in at Toyota quite quickly, as he knows about the F1 KERS systems and how quickly they can run down, even if there are some pretty big differences.

[TF110]

Toyota started out with the Hybrid car. Audi hasn't. They haven't said how many tests they've had with the Hybrid Audi. We know Toyota has had at least 3. And one was a 30hour test. Minor issues doesn't equate to the car being flawed. Audi isn't on the back foot, but I think Toyota is further ahead in the testing aspect of their Hybrid car than Audi is.

[gwyllion]

Audi has already done some serious testing. We know that the shakedown of hybrid R18 was done in October and that they tested in Paul Ricard (November), Sebring (December), Abu Dhabi (January), Road Atlanta (March).

We also know that they will test in Sebring next week. Audi typically also does an 30 hours endurance test with multiple cars at Paul Ricard before Le Mans.

It is safe to assume that the components of the hybrid system have also been tested extensively on dynamometers before they were tested in the car.

[TF110]

That doesn't mean that they are already ahead of the curve with the Hybrid system. That's my point. Chernaudi seems to think Toyota is behind because they had some minor issues in their endurance test. I'm just pointing out we have no clue who is ahead. Audi had a couple issues today in their race at Sebring. No one is immune!

[FstrthnU]

Well, The #2 Audi won Sebring, so grats to the old guys! The #2 ran a near-perfect race, the other 2 ran into problems (the 3 very late in the race, the #1 very early)

[deggis]

Walk around of the e-tron in the Sebring sunset:

http://www.youtube.com/watch?v=mKg01yMHfF8

:fap:

[chernaudi]

Wasn't there some speculation that the new R18s could be running pullrod suspension? If so, based on the issues that Ferrari have had on their F1 cars, I'd bet against Audi doing that, as well as the fact that on modern LMP cars any advantages of the pullrod system are canceled out by the raised nose and issues with maintenance.

I think that the R18 e-tron and Ultra will have a pushrod system, very similar to what the old R18s had.

[gwyllion]

There is no reason to speculate. The R18 e-tron quattro press kit (page 9) is conclusive:

Front and rear double wishbone independent suspension, front pushrod system and rear pull rod system with adjustable dampers

BTW That document describes the gearbox housing as

Carbon-fiber composite with titanium inserts

[gwyllion]

Joest has a new website, a facebook page and a twitter account.

The website contains a description, including technical specification, of the R18 ultra and the R18 e-tron quattro.

[gwyllion]

Originally Posted by gwyllion

There is no reason to speculate. The R18 e-tron quattro press kit (page 9) is conclusive:

http://www.audiusa.com/us/brand/en/e...i_r18_tdi.html describes the suspension of 2011 R18 TDI as

independent front and rear double wishbone suspension, pushrod system with torsion bars and adjustable dampers

The pictures on Mulsanne's Corner confirm the rear push rod suspension: picture 1, picture 2 and picture 3.

That mean that Audi not only changed the gearbox housing/casing for the 2012 R18 but also the rear suspension layout (pull rod instead of push rod). The front suspension is probably also modified to make room for the drive shaft.

[chernaudi]

Pullrods have become popular again on F1 cars for the rear suspension partly at least for areo reasons. I do wonder if it has some positive effects at the rear as far as grip, but we do know that Ferrari have struggled with the pullrod system up front on the F2012.

It seems like Audi have decided to get around any such issues with the pullrod system by sticking with pushrods up front.

[gwyllion]

Originally Posted by chernaudi

Pullrods have become popular again on F1 cars for the rear suspension partly at least for areo reasons. I do wonder if it has some positive effects at the rear as far as grip, but we do know that Ferrari have struggled with the pullrod system up front on the F2012.

It seems like Audi have decided to get around any such issues with the pullrod system by sticking with pushrods up front.

http://scarbsf1.wordpress.com/2010/1...-aerodynamics/ clearly explains the benefits of push and pull rod. Both approaches are "equal in terms of their effectiveness as controlling the wheels." So there is no grip improvement, only a lower center of gravity and perhaps a lower engine cover above the gearbox.

Another good article is Lister Storm LMP designer reveals his trade secrets for suspension design. Remember that Andy Thorby used pull rod at the front suspension in the Lister Storm LMP, albeit coil spring instead of torsion bars:

source: http://www.mulsannescorner.com/listerstormlmp-4.html

[TF110]

I always liked the Storm LMP. Nice to read about it again. Brings up the 'blown diffuser' question in my mind again. I don't know if it's allowed or not, but the suspension arrangement is interesting as well.

[gwyllion]

Indeed, the Lister Storm LMP had some nice innovative features. The front wheel arches from the latest HPD ARX-03a appear heavily inspired by the Lister. In http://www.mulsannescorner.com/listerstormlmp-4.html Andy Thorby explains his motivation for the unusual fender shape.

BTW I would not call its exhaust solution a blown diffuser because it probably did not improve the rear downforce.

Looking into the exit from the rear we can see where the exhaust pokes into the duct enhancing the low pressure and encouraging the air flow from the engine bay to exit out the rear of the car. Andy Thorby, "This works quite well at sucking the air out of the engine bay, mainly, of course, the air that has passed through the radiators."

source: http://www.mulsannescorner.com/listerstormlmp-3.html

[chernaudi]

I do wonder what the motivation was for Audi to run a pullrod rear suspension. Only thing I can think of is packaging. This does make some sense--with the way that Audi have tended to mount the suspension to the gearbox (the sides of the casing) doesn't make much difference with CG, but Audi more than likely reverted back to the cassette type of gearbox sub-assemblies, getting the some of the suspension parts away from the exhaust pipe, and perhaps the R18 is running an inerter system like Toyota are alleged to be using.

This is, after all, the layout that most F1 teams (namely McLaren and RBR) have stuck with since 2009. The blown diffuser probably doesn't mean much to the R18, with the rules and simple design parameters ruling it out, but the R18 may very well be using inerters on the 2012 spec cars, and there are packaging advantages to the pushrod front and pullrod rear solutions.

[TF110]

Originally Posted by gwyllion

Indeed, the Lister Storm LMP had some nice innovative features. The front wheel arches from the latest HPD ARX-03a appear heavily inspired by the Lister. In http://www.mulsannescorner.com/listerstormlmp-4.html Andy Thorby explains his motivation for the unusual fender shape.

BTW I would not call its exhaust solution a blown diffuser because it probably did not improve the rear downforce.
source: http://www.mulsannescorner.com/listerstormlmp-3.html

No I didn't mean the Lister LMP had a blown diffuser, I said it brought up the question about them with it's exhaust solution being quite close to it.

[chernaudi]

I'd think that it would be closer to the original Audi R15 channel concept than the blown diffuser. Even the R18 to an extent still uses the channel system.

[TF110]

Ok, that isn't my point. I'm saying with the recent blown diffusers in F1 going on if any prototype might consider this. And the lister brought it to my mind again.

[chernaudi]

Sorry to double post, but I was re-reading the Joest Racing articles, and for the R18 Ultra, some references were made to using the suspension to optimize weight. Could this be another reason why pullrods were chosen at the rear? I did read that a pullrod suspension could in theory be made lighter, but that was from a book written about 15 years ago, and we all know how much technology has moved on since then.

And there was argument as to the R18 and the 908 using blown diffusers last year, and that was largely debunked because of the low RPM of the diesel engines--even the 3.4 V8s probably don't rev high enough to have a significant effect. That, and the rules and packaging of the cars sort of rule it out. Exhaust gases are used a bit on these cars to manipulate airflow, but that's mostly over the rear bodywork, and has little if any direct effect on the rear diffuser, which is near spec on all of these cars.

It seems that more worthwhile work can be gained off of front diffuser development.

[gwyllion]

Originally Posted by chernaudi

I do wonder what the motivation was for Audi to run a pullrod rear suspension. Only thing I can think of is packaging. This does make some sense--with the way that Audi have tended to mount the suspension to the gearbox (the sides of the casing) doesn't make much difference with CG, but Audi more than likely reverted back to the cassette type of gearbox sub-assemblies, getting the some of the suspension parts away from the exhaust pipe, and perhaps the R18 is running an inerter system like Toyota are alleged to be using.

The advantages of a pullrod suspension are clearly documented. The rockers and torsion bars are mounted lower on the gearbox and the third spring/inerter is positioned horizontally at the bottom of the gearbox. This lowers the center of gravity.

You are right that in case of the Audi R18 this also creates more room for the central exhaust. In the 2011 the exhaust had to go over the third spring/inerter, which is marked as 4 on the following picture:

With a pullrod solution the third spring/inerter is no longer located on top of the gearbox. So the exhaust does not have to bend around it and it can be positioned a bit lower.

[TF110]

Exhaust gasses are used in F1 to help rear downforce, they still use them even though the exhausts aren't in the floor. The way that they can be used on F1 cars by directing the flow of the gases over bodywork could possibly be used in prototypes. So I don't see much of a big difference. But I'm not mr. technical, so I'm not entirely sure if it's even relevant to the R18.

[gwyllion]

The first pictures of the R18 ultra test car in the Sebring paddock: http://www.quattroworld.com/audi-r18...ra-at-sebring/. Note that the car is not yet in 2012 aero specification.

Keep checking that website for updates:

Today we spotted the R18 ultra in the paddock at Sebring. Audi will be testing the car tomorrow along with the newly announced Audi R18 e-tron quattro. We will be attending the testing and will post more photos as soon as possible.

Hopefully they can tell us how much faster the R18 is in its 2012 trim.

[gwyllion]

http://tv.audi.com/video/27612 explains why Audi went to right hand drive for the R18.

I love that the engineer Chris Reinke considers the driver as ballast that has to be positioned correctly in the car

[Bentley03]

Originally Posted by gwyllion

Note that the car is not yet in 2012 aero specification.

Presumably in order to compare data accurately with the data accrued from the old car during race week?