March/April
2010
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All news content copyright Michael J. Fuller, unless
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|
 4.14.10* updated 4.15.10
>>This
photo was taken last weekend at Paul Ricard. It shows the
underside of the Audi R15 plus' front splitter and is interesting for
the appearance of the vortex generators. The use of the VGs
seems to indicate that conditions are ideal for detached flow on
the underside of the Audi's splitter (asymmetrical cross section, 30 mm
trailing edge thickness). But this should be somewhat expected
considering the reduced height bodywork has made the operating
conditions for the splitter a little more difficult inasmuch as the
flow off the trailing edge is concerned. On the previous R15
execution a lot of work had gone into providing the front wing and flap
with ample airflow allowing for maximum pressure recovery.
That's why the covering bodywork was mounted high and shuttered.
But the lowering of the front bodywork on the R15 plus has simply
made ideal pressure recovery for the splitter unachievable.
But
there are whispers that the flow separation is intentional to an
extent. Certainly part of the flow separation is the simple fact
of life of the the splitter's design and execution. But we
understand that there is also beneficial aspect; the separated flow has
less energy and it makes picking up sand and dust and exhausting it
directly into the radiators less likely, as long as it is
directed to behave in such a manner. The VGs simply allow for this entire condition to be better controlled.
Looking back to 2008, the Audi R10 had a very similar treatment. Was there ever any discussion of cooling issue on the R10?
Interestingly,
flow detachment was less of an issue on the R15's front wing as the
mainplain/flap injected high energy flow into the underside of the
assembly helping the airflow stay attached. But then again the
R15 did suffer from sand pickup clogging the intercoolers at Le Mans
last year. The drawback was that this setup was much more pitch
sensitive.
Every solution has its negatives.
It also comes to our attention (via RCE's Sam Collins) that the R15 plus is running on 33/68-18 Michelins at the front and 37/71-18s at the rear. Same as the R15...same as the R10.
Furthermore, Wouter Melissen tells us the internal rear channel ducting has been completely removed.
Photo courtesy Wouter Melissen, www.ultimatecarpage.com. |
|
 4.2.10
>>Two (make that three) videos have appeared on YouTube of the Audi R15 plus testing at Monza yesterday. They are here, here, and here.
We noticed this detail, the lower quarter of the trailing edge of
the front fender is scalloped out to allow for additional venting of
the front wheel well. |
 The area between the front wheel and the tub appears rather opened up, especially compared to the R15. |
|
3.31.10
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|
|
 3.25.10* updated 3.26.10
>>More
shots from Audi's R15 plus testing at Sebring (see Robon Thompson's full gallery). We pointed out the
inner fender bulge originally (3.15.10 news item), but this shot has us
really wondering what's going on there. Previously this area of
the R15 was covered by the high-mounted shuttered bodywork. This
was designed to allow the wing  elements below to "breath" more
efficiently. But with the bodywork lowered, the inner fender was
unveiled and these bulges became necessary to cover the tire. But
it's the size of the bulges
that has us scratching our head. We're
presuming Audi is going through a testing program trying out various
front wheel widths. How wide are they, as wide as the Acura ARX-02a's
were last year? Naturally we don't know, but these bulges
certainly aren't merely there for bodywork clearance for the tires
through steering lock.
But as always, we reserve the right be be seeing things that aren't there. |
|
 3.23.10
>>Audi began a 5 day test starting this past Monday in order to shakedown the updated Audi R15 plus. In
spite a significant off yesterday in Turn 17 that reduced the one and
only R15 plus into jagged carbon bits, the car was back on track this
morning, according to Robin Thompson.
In
this rear shot we can see the new legality louvers that cover the rear
tires as seen in rear elevation. Interestingly, the regulation , Art
3.4.1 b/, states, "(the rigid bodywork masking the rear tires must...)
Be designed in such a way that air passing through them
is directed toward the ground at the exit." It would appear the
R15 plus' louvers direct the air up towards the rear wing at the exit.
An interesting detail is that at the outboard corners the louvers
are inset to just cover the rear tires opening up an offset that allows
unhindered air to vent out the rear of the fender wells. The
exhausts exit out the car similar to the standard R15. |
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|
 3.21.10
>>Julien over at endurance-series.com sent this over last week. In one shot we
have a comparison of the Peugeot 908's two available front diffusers.
The top diffuser is the Le Mans low-downforce variant that was
raced only at Le Mans last year. The bottom diffuser is the
sprint version and was raced everywhere barring Le Mans. Arrows
denote the differences. Surprisingly these differences are
ultimately minor (but for one major exception); a radius inboard is
sharper on the Le Mans version, the shape going outboard is flatter on
the sprint version, and the camber of the turning vanes is more aggressive on the sprint version.
Naturally the one major difference is that air blows through the
front suspension and directly onto the sprint version's trailing edge
(30 mm thick by the way, per regulations given the asymmetrical wing
section being used on the 908) while on the Le Mans version air goes
over the top of the bodywork. |
|
 3.20.10
>>An
additional image has been released by Audi of the R15 plus. This
view reveals the side profile and shows that the rear fender profile
has been completely changed with the leading edge shape extending much
further forward and the trailing edge shape being less aggressive.
We're now only lacking a shot of the rear of the car. The
turbo intake has also changed though appears an iteration (at least in
the "style" of...) of the 2009 Le Mans intake but larger and
repositioned. Furthermore, the rear wing position has shifted yet
again. When the R15 initially appeared last year the rear wing
endplates extended past the rear bodywork. At Le Mans this was
revised and the wing was shifted forward and the endplates were in line
with the rear bodywork (noted by the more extreme "question mark" shape
of the mounts as the rear wing was shifted forward and thus positioned
more directly above the mounting location). This revision carried
on from Le Mans through the rest of the season. Looking at the
R15 plus and noting the angle at which the mounts visually appear to
intersect the top of the fender profile it's pretty clear that they
have been designed to scoot the rear wing rearwards. Naturally
looking at the endplates gives us the additional (and more obvious)
clue as it is now extending past the rear bodywork again. This is
in a further effort to shift downforce rearward compensating for
the major revisions there (and see additional comments below,
3.15.10, regarding the changes to the front designed to rebalance the car aerodynamically). |
|
 3.17.10
>>Images from Sebring testing are trickling in. Mike Callahan
sends these along. Here we see the first rear shot of the updated
for 2010 Lola. The area just behind the tires is now covered and
louvered (though the louvers aim downwards in compliance with the
regulations) and the outboard area of the fender now is sealed all the
way down to the legality plate (yellow arrow). The rear trailing
edge body gurney is of huge proportions though similar to last year
given the rear wing span reductions and the desire to recoup as much
lost downforce as possible. |
 At
the front the Drayson Lola's central brake duct has been closed off
with a plate and the older brake inlets brought back into service.
|
 The
Peugeot 908 also has its huge gurney from last year as well as the two
cute little gurneys we saw at Petit last year attached to the outboard
ends of the fender. The 908 does look smart in its new livery. |
|
 3.15.10* updated 3.17.10
>>This just in...Audi releases image of the R15 plus. |
 The
nose vent is gone revealing the raw crash structures. This seems
to speak to a particularly functional design execution that took into account
the desire to not
have to re-test the nose crash structure. Therefore the crash
structures were left alone and modifications made around them.
The vent's inset
leading edge (located between the two crash structure cones) now has a
different shape (we can see a bonded on panel). The changes
effected here really are in response to the large changes at the rear
and an effort to rebalance the car. We're told the impact of the
nose vent was minimal compared to the elimination of the rear channel
concept.
Also note the riveted/bonded panels on the inboard face of the
front fender to allow for wheel movement. This area was
previously covered up by the large louver panels that used to cascade
over the top of the nose. |
 Now
on either side of the nose reside new wing sections. Note that
the bodywork between the fenders has been substantially lowered.
We understand that ultimately this causes issues with airflow beneath
these bodywork elements; the height here is critical and the lower
these elements are, the slower the circulating airflow is in this area
(hence why the R15 was designed the way it was with the cascading
panels high up on the car in this area allowing flow to pass through
them and helping pressure recovery of the wing elements below them).
But it would make sense that lowering them would shift downforce
rearwards and reduce drag overall. The front
splitter/wing element has been redesigned as well. This was an area of contention
given the symmetrical wing elements that made up the R15's device and
effectively created a front wing mainplane and flap. From what we
can see in this image, the flap is gone but the mainplane remains and
it now has a variable length trailing edge. The wing mounts are
rather inelegant, amounting to little more than rounded posts. |
 At
the rear the large duct that allowed air to blow around the gearbox and
through the rear suspension has been eliminated. This was a
primary source of internal controversy at Audi and contributed to the
car's relatively
high drag at Le Mans. But then of course the R15 was carrying a
lot more downforce than it's rivals (though this appeared to have cause
issues with the Michelin's). The twin channel concept
came about through a different method of deriving the car's aero
target. In the past the the drag level was set and the package
was developed by adjusting the target L/D. But the new method of
thinking set a target range of downforce and again L/D was adjusted as
needed with drag being what it was for the given L/D. But the
problem was the amount of drag that the rear channel concept
contributed, even it it was efficient from a downforce standpoint.
And if Le Mans was your goal this wasn't really the route you'd
head in. Now on the other hand, if you were interested in racing
at venues such as your typical ALMS track, then you'd tend to want to
have a look at the channel concept as it was very efficient if only
considering very high downforce setups. But as downforce was
taken off it became less and less efficient, thus at the opposite end
of the spectrum this aspect of the R15's design concept couldn't "pay"
for it's ride at all. |
|
 3.12.10
>>Today Audi released this teaser image of what we're told is the "interim" R15 plus (effectively it is
the definitive car but for a few details that are as yet to be hammered
out prior to Le Mans) as it was loaded onto a transport, presumably on
it's way to Sebring. No, not for the 12 Hour race next weekend;
Audi has decided to sit this one out and instead will test in the days
following the race. |
 Here
we can see a close up of some of the detail changes. It seems
evident that the louvered side pods are gone. At very least the
louvers are gone from the outboard vertical face of the side pod.
Additionally, the trailing edge of the front fender pontoon has
been revised and the outboard plate that extended back to the rear of
the car and blended into the rear channel duct is gone. From this
angle it also appears that indeed the rear duct itself is gone, thus
too the channel aspect of the R15 design. It is our understanding
that early on in the initial development of the R15 a more conventional
design was considered. It would appear the R15 plus has adopted
some of those details and done away with some of the
more interesting, though controversial, elements. |
|
|
 3.11.10
>>Last
month Strakka Racing shook their Acura ("HPD") down at
Algrave in
Portugal. But this past weekend was the Le Mans Series test
at
Paul Ricard and Strakka Racing debuted a closer-to-specification
ARX-01c. The car that was seen at Algrave was effectively the
ARX-01b but for the revised rear wing (image right). But the
-01c as seen at Ricard (image below) had a number of new details.
Nick Wirth has indicated all modifications for the -01c were
developed exclusively in CFD. But more importantly, "The ARX-01c run in
Paul Ricard is as much of an update aerodynamically as the -01a was to
the -01b." |
 |
 One
of the more interesting details is the new turning vane on the leading
outboard face of the fender. This is very similar to a device
on
the Zytek LMP (image below). Interestingly the front
diveplane
appears to have been designed to work in conjunction with this turning
vane. It was always our understanding that the turning vane
was a
device to shed drag to gain efficiency. Going way back, the Reynard
2KQ
utilized a similar device, called a truck vane, to reduce the initial
iteration's high drag. The flush front fender
louvers appear
to be molded into fender, there doesn't seem to be a separate
changeable louver panel. Less significantly, the headlight
bucket/bezle also appears to have been changed leading one to wonder if
indeed the entire front fender shape has been massaged. When
asked, Wirth deferred specifics only stating that, "There are many new
parts on the car front and back, and it is a big step forward
aerodynamically from the 01b." |
|
 |
|
 |
 On
the ARX-01c the fender trailing edge bodywork is similar to the original
Courage LC75. It also extends back further terminating in
line
with
the rear wing. Note also that the rear legality structure is
different
with a convex leading edge ramp as compared back to the -01b (image
right). The rear brake intake has moved from the lower
position
up to
on top of the side pod ahead of the rear fender leading edge as similar
to the ARX-02a. Finally, note
the solid endplate without the trailing edge notch. Wirth
also indicated that we should, "Expect
further
variants to appear both in Europe and the USA this year..."
Naturally then we should see detail differences between the
ALMS-based Highcroft and LMS-based Strakka cars. Wirth has
indicated mechanical changes also accompany the -01c though he would
not elaborate what those changes actually are. |
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