Back-to-back events never really give teams a chance to bring anything new to the table at the second GP event and Brazil was a classic case of this as the F1 circus headed straight from Texas to Interlagos.
Much of the weekend’s practice sessions was spent analysing components ahead of 2015, using large pitot tube arrays to gather information about critical areas where airflow is passing. Whilst CFD and wind-tunnel testing are pretty reliable it is important to transfer the knowledge gained in the factory to the track, hence why the often-used C-word, correlation, is vital to the performance of an F1 car.
Kevin Magnussen spent most of FP1 with two pretty big pitot tube arrays attached either side of the cockpit, pointing towards the back of the front suspension assemblies. Taking measurements from both sides simultaneously is advantageous as the engineers get a more complete picture as to how the airflow is behaving along both sides of the car is it travels, rather than traditionally only measuring from one side of the car.
The purpose of the arrays is to constantly monitor the pressure of airflow at specific points as the car’s speed varies. They will then run the same (or similar) test in a factory environment and hope that everything matches up. If so then the team has the confidence to develop new parts without the fear that they won’t work as intended.
The drivers will never do a flat-out lap with the arrays attached as they risk ripping them off their carefully designed, bespoke mounts – they are pretty expensive! Instead they are told to do constant speed runs or a certain speed through a certain corner to gather accurate and consistent data across a certain speed threshold. Whilst there tends to be no speedometer on an F1 steering wheel, the driver may be asked to hold 6th gear at 8,000rpm, for example, which will be the necessary speed that the engineers are after.
McLaren could even have been assessing their slightly tweaked front wing endplates, which feature an undercut edge and small lip at the back of the fence and main body. This encourages airflow to pass around the front tyre by making the most of the low pressure zone at the beneath the wing.
Lotus also ran some generic pitot tube arrays, although it was another sensor which caught my eye on Friday.
The E22 had a unique camera mounted off the inside face of the left front wheel hub, facing in towards the sidewall. The camera monitors how the sidewall deflects under loading, as the way the tyre behaves varies at not only speed but also pitch, yaw, and roll. Tyre behaviour has a huge influence on the airflow passing around the leading edge of the floor and the sidepod, so it is important to understand how the natural loading effects on the car have an influence on the path of airflow downstream.
Aero sensitivity has been one of Lotus’s key weaknesses this year and the above could well be a contributing factor. The structure of the tyres has changed drastically since 2013 and therefore the way air behaves as the tyre loads up has also changed. With all the devices beneath the chassis and how the teams produce the Y250 vortex to seal the floor via the front wing, it is very easy to get a bit lost with the tyres’ interaction with air as it’s a constantly fine-tuning process. It is virtually impossible to map these effects sufficiently, with only Red Bull really having a firm hand on this technology at the moment.
The tyres remain virtually unchanged going into 2015 so Lotus may well be able to sort some of their issues ahead of the start of next season by using the above device.
Speaking of Red Bull, something I forgot to mention in my US GP Tech Highlights was their introduction of a new Y100 (monkey seat) winglet. The winglet is a revised version of their high downforce specification model which previously held two elements between a set of small endplates.
The new winglet now adopts an additional third element that is tucked behind the trailing second element, creating a two-stage design. Mercedes have led the way in terms of development around this region although it appears Red Bull have decided to adopt a similar, multi-level approach to their winglet from now onwards.
Its purpose is to entrain the exhaust plume and force it upwards towards the base of the rear wing, allowing a higher angle of attack to produce more downforce without stalling the rear wing. Mercedes appear to have a good grasp on this effect so it will be interesting to see who can play catch-up going into 2015.