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Tuesday, April 16, 2019
We are already three races into what appeared to be a season where we’d finally see Ferrari break their championship title drought but, they’re suffering a similar fate to the one their closest adversary has in recent years - they have a car that’s difficult to get the best from at a given race weekend.
If they’re to unlock the SF90’s
full potential they may actually have to neuter some of its raw speed
in favour of better apex speed and balance for the drivers, whilst
also making ground on the silver arrows who have started to tame
their own unwieldy beast.
Make no mistake about it, both cars are
leaps and bounds ahead of the competition and recent struggles from
Ferrari have flattered the position of Red Bull relative to the pair
in my opinion. Furthermore, Red Bull remain a disruptor
in terms of strategy, taking the outside shot when possible in order
to put themselves in the mix but really lack the pace if both red and
silver cars were operating optimally.
For me Ferrari have one of the oldest
problems on the grid, getting these three aspects to work well in
unison - tyres, suspension and aero. In isolation perhaps they appear
to be working well but it’s the transitional moments that we’re
interested in, the nuance of when one system leans on the other.
Heave-ho
When I’m sat thinking about Ferrari’s
conundrum I’m immediately drawn back to testing and the apparent
issues they were having with their suspension system. They were
trying to push the envelope with a revised layout that they hoped
would actually work better in the very circumstances we’re talking
about, helping them both mechanically and aerodynamically.
One of the most intriguing aspects of
suspension design over the last few years is the ‘heave’ or
‘third’ damper, as it is the bridge between the aerodynamic
platform and suspension and plays a pivotal role in the transient
behaviour of the tyres as they deform.
‘Heave’ if you’re unaware is a
suspension mode that relates to the combined (front and rear)
vertical displacement of the car. Heave is problematic for open wheel
cars, especially with tyres that have such large sidewalls as we have
in Formula One. This is due to the fact that as downforce increases
and the car depresses toward the track surface the tyre changes
shape, which if left to its own devices can become detrimental to the
aerodynamic performance of the car.
The heave element is used and setup to
counteract this issue and like the rest of the cars setup will be
tuned to suit each driver and the prevailing track conditions. Of
course just like with any system money spent on developing it will
usually yield results and Ferrari have invested in finding
performance here, especially as they knew that the change in
regulations for 2019 could have a bearing on how they operated.
In response to this it’s understood
that Ferrari moved to an independent heave damper at the rear of the
car for 2019, whilst also making the necessary adjustments at the
front of the car to take advantage of any performance uplift.
However, having encountered problems during the pre-season test I
understand they had to dial back their approach and are currently
looking for ways to regain their perceived advantage.
Fully loaded
Many column inches were devoted to the
very different approaches taken by teams when it comes to their front
wing designs for 2019. And whilst many were quick to judge the
Ferrari/Alfa Romeo solution as the best, given it was the most
aggressive, I tried to sit on the fence a little as Mercedes and Red
Bull, two teams at the opposite end of the rake spectrum had stayed
the course with a more conventional design. If either of them had
chosen this more radical route then yes, fair do’s I’d sit and
listen to it being the second coming but I still had to be convinced.
The designs seen at either end of the
spectrum are still essentially trying to do the same thing, just in a
very different way, as they both look to mimic the outwash effect
used for the last decade whilst making enough downforce to balance
what’s achievable at the rear. So, we must discuss the primary
reason why Ferrari opted for their design over what many would deem
the conventional route taken by Mercedes and Red Bull and the main
one would appear to be how they deal with the tip vortex.
The vortex created by the 2019 front
wings are much stronger than before due to the simplification of the
endplate and loss of other flow diverting furniture, that would
otherwise help to soften this vortex. Furthermore, the move to a wing
which is as wide as the car also positions this vortex further
outboard than is desirable, as previously it would have helped to
pull airflow across and around the tyre differently.
When I say it’s undesirable, I mean
undesirable to the designer, as the flow structure is
counterproductive to producing flow downstream. It makes creating the
type of outwash that was possible under the previous regulations nigh
on impossible, with airflow drawn in much closer to the car as it
moves downstream. This is a win for the rulemakers as that means the
wake created by a lead car has a much smaller footprint and is why
we’re able to see cars run a little closer to one another this
year.
The design favoured by Ferrari, Alfa
Romeo and Toro Rosso sees the flaps arch over and connect with the
endplate at a very low height (see the yellow mark for a visual idea of how low the flap/endplate juncture is, a feat more exaggerated on the SAlfa). Perhaps overlooked so far in everyones generalisation of these wing shapes is that the flaps are also essentially flat by the time they meet the endplate. This would suggest that these teams are trying to propagate a vortex
that’s not only shed lower down, lessening its vorticity, but also being forced to rotate differently too.
It’s not as simplistic as that (of course) as
there are many other flow conditions to consider at this juncture
too, including but not limited to the low pressure flow beneath the
wing, the design of the inner and outer footplates and also the
position of the strakes beneath the wing. We must also then consider how this
arched style flap arrangement impacts downforce creation and the subsequent direction of flow that's cast off it, whilst also bearing in mind the
shape, direction and vorticity of the Y250 vortex as it still plays a significant role in how airflow moves down the central portion of the car.
As a matter of comparison let us take a look at Red Bull's wing, as they've opted for the more conventional full flap arrangement that meets high up with the endplate and essentially encourages the strong tip vortex to form that Ferrari have discarded. Now, those that have this design have started to soften their approach, with Red Bull and Mercedes having used notches in the upper rear corner to displace the vortex, almost in a similar way to how you see teams do so on their rear wing endplates.
However, Red Bull had to revert to a full length endplate in China and Mercedes had to adjust their new design, as both fell foul of the FIA's interpretation of the regulations - http://www.somersf1.co.uk/2019/04/the-fia-tidy-up-some-front-wing.html
The interesting thing for me here is that the teams that favour this fuller flap solution seem keen to not only harness the tip vortex but also utilise the airflow cast off the flap to shape the wake created by the upper portion of the tyre, something that the Ferrari/SAlfa/STR solution sacrifices.
Meanwhile, we have a large collective of teams that are trying to have their cake and eat it, with halfway house approaches that take into account both aspects but don't fully deal with them at the far end of the spectrum.
After some digression I think it’s fair to say that the
Ferrari/SAlfa/STR approach leaves them a little wanting when it comes
to the amount of direct downforce generated by the front wing,
meaning they can’t quite get the car on the nose as much as some of
their counterparts in the corners and front axle load is obviously
quite pivotal when we come to generating heat in the front tyres.
Black Art
So, I think we now have to wander into
tyre territory, as whilst recent studies and comments have pointed a
finger at the SF90 not being able to generate enough downforce I also
think their relative tyre performance is a little lacklustre too.
The first things to think about when we
talk about tyres in 2019 is that the game has changed a little
compared with last season, with Pirelli opting to use the thinner
gauge tread they used at several races in 2018. Furthermore they’ve
reduced the tyre blanket operating temperature at the rear of the car
but not the front and obviously we must consider that each of the
compounds has its own temperature window, meaning we’ll also get a
variance in performance from tyre-to-tyre.
I know the obvious statement is that all of the teams must overcome these issues but I think Ferrari are having
the edge taken off their performance due to the way their operating
their tyres (due to their suspension and aero inefficiencies).
Furthermore, if we look at the three circuits that the teams have
visited thus far I think it exposes the cars fragility's, with it
unable to work efficiently when it’s bumpier or the track has a
coarse surface. Meanwhile the lack of front axle load means the tyres
aren’t being heat cycled correctly and this becomes damaging not
only over a single lap but even more so over a race stint.
In conclusion
I've tried to generalise some of the issues in this article in order that we cover a lot of ground and as you've probably come to realise I don't think they have one specific issue to deal with in order to unlock the SF90's potential. However, I don't think these issues are insurmountable either, it's just about how much ground they'll have lost by the time they get to a competitive state, especially as Mercedes have got on top of their own issues in double-quick time.
I would hope that the team have a large package of parts in their schedule that'll be ready for the return to Europe and that we might see both Ferrari and Mercedes go toe-to-toe from theron.
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