Guest writer John Beamer reviews the technical changes on the cars at the Canadian Grand Prix.
Before the new 2009 regulations we tech spotters used to see much more variation in aerodynamics at the different races – especially at high-downforce Monaco, and low-downforce Montreal and Monza.
But these race-to-race changes have more or less disappeared.
Take Monaco, for example. In the past teams would turn up with an impressive array of aerodynamic appendages to try to maximise downforce around the principality. Here top speeds are not a factor so teams are willing to add downforce at the cost of drag, a trade-off that wouldn’t be made at, say, Barcelona.
However, this year at Monaco teams didn’t bring any new high downforce components – all they did was ratchet up the wing angles.
So what about Canada? The track favours a low downforce set-up, similar to Monza, but not as extreme. The Gilles Villeneueve circuit consists of a series of lengthy straights, a few chicanes and an slow hairpin with no high-speed corners to speak of.
Naturally all teams came with low-profile rear wings but most were simply existing wings with modified angle. Williams and Renault were among the few to use new, low-downforce concepts, both of which featured twisted spans.
Renault had an M-shaped wing which eagle-eyed readers will recall was an approach used on the car for the Canadian Grand Prix last year. The idea is to try to optimise load distribution across the length on the wing.
The curvature either side of the centreline aligns better with the incident airflow so presents a reduced angle wing. The theory is that this increases the aerodynamic efficiency (defined as the downforce-to-drag ratio) of the wing by better reflecting the shape of the incoming airflow.
The Williams concept was a little different. It is shovel-shaped to try to increase downforce over the middle part of the wing where the airflow is cleaner.
By making the mid-wing do the work the pressure gradient is reduced at the endplates, which produces smaller vortices and less drag.
Designers are investing substantial resources in optimizing the DRS system and this is also evident in the Williams design.
The flap has a short chord and its job is to keep the airflow attached to the underside of the main plane. The flap extends the low pressure area behind the rear wing which in turn increases downforce of the device. When the DRS is activated this low pressure area drops away and the lee-side of the main plane stalls, causing a large drop in drag (and downforce).
Neither Renault nor Williams ran their new front wings in the race because of the threat of rain.
There were also fears that the super-soft tyres would last only a few laps. Under this scenario more rear downforce would help preserve the tyres.
This also explains why McLaren opted to run its cars with more rear downforce and was one of the reasons why Jenson Button was so much faster than Sebastian Vettel on the drying race track at the end of the race.
One reason why we don’t see vastly different car configurations on a low downforce circuit like Montreal is because of the extreme aerodynamic sensitivity of the cars. Following the 2009 regulations changes, teams achieve optimal downforce by treating the car as a system.
Ostensibly this means tailoring the intricate front wing design to optimise airflow to the sidepods and floor. However, given the sensitivity of the aerodynamics, teams don’t have a lot of latitude to radically change the front wing because all their aero optimisation work will be undone – this is 18 months-worth of intensive CFD and wind tunnel analysis.
As a result teams rarely produce radical new front wing designs – the last such example was probably McLaren which introduced the split cascade to manage airflow around the tyres in the middle of 2010.
Interestingly for Canada Williams introduced an endplate-less front wing. The endplates were merged into the cascades and a horizontal vane is attached to the integrated endplate to manage air to the tyres.
In addition a fence was placed underneath the outer part of the cascade in order to control the vortices below the front wing. This will aim a vortex outside the tyre to try to reduce wheel drag.
One of the surprises when the 2011 cars were launched was Ferrari’s decision to stick with pushrod rear suspension at a time when many other teams were following Red Bull’s lead in switching to a pullroad configuration.
The Scuderia was very aggressive with its placement of the suspension pick-up points to try to create as narrow a back-end as possible. The intention is to enable as much air as possible to channel to the coke-bottle zone and over the diffuser. One consequence of this set-up is that Ferrari is quite harsh on its rear tyres, particularly the harder compound.
In recent races the team has subtly altered the suspension pick-ups to try to better manage the rear tyres. By fine tuning suspension pick-ups it is possible to control the weight transfer under breaking, accelerating and cornering. The team is no doubt attempting to get a more consistent weight distribution to the rear tyres under dynamic conditions.
Another suspension innovation that Ferrari has adopted is a dual-rate anti-roll bar. As its name implies the anti-roll bar resists roll – in a road car you can feel the car rolling when cornering. The stiffer the bar the greater the resistance to roll. A stiff bar will keep the car at a consistent attitude, which is beneficial for aerodynamics. A softer bar will give more mechanical grip when cornering.
Dual-rate anti-roll bars give the best of both worlds. Typically a stiff bar is attached to the suspension with a soft-sprung coil. The coil gives compliance when cornering but quickly becomes fully compressed allowing the stiffer anti-roll bar to resist rolling motion.
The debate over the future technical direction of F1 continues. After the Canadian Grand Prix it was confirmed that from Silverstone teams would be limited in their application of hot-blowing diffusers.
When off the pedal the throttle is only allowed to be up to 10% open – many teams maintain full throttle opening, especially in qualifying. To restrict this the FIA has also mandated that, from this weekend, engine maps must not be changed after qualifying (unless a driver starts from the pitlane). This means that teams will have to run less aggressive maps in qualifying.
The impact is likely to be significant, especially for Renault and Red Bull, the two teams that first developed the technology.
The most intriguing dynamic is whether Red Bull’s qualifying advantage is reduced – given the RB7 has almost a second on its rivals in the hands of Vettel I suspect the Milton Keynes-based outfit won’t be too concerned. However, we will need to wait a couple of weeks before we know exactly what the regulation change has done to the running order.
The bigger change affects the 2012 regulations where exhaust-blown diffusers have been banned.
An early proposal was for the exhausts to extend a minimum of 330mm behind the rear wheel centre line, which is at the trailing edge of the diffuser. This would have prevented the use of blown diffusers but would have incurred significant costs as teams produced longer exhaust pipes.
There was also a strong likelihood that teams could still take advantage of the blown effect to reduce the pressure gradient aft of the diffuser or underneath the beam wing, both of which would yield a performance advantage.
A compromise has since been reached whereby the periscope exhausts of years gone by will be mandated. It is unclear how the regulations will be written to ensure this happens but it will mean that there is very low chance of the exhaust gasses being put to aerodynamic use.
This is a guest article by John Beamer. If you want to write a guest article for F1 Fanatic you can find all the information you need here.
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Image © Ferrari spa/Ercole Colombo