2015 Chinese GP Tech Highlights

Note: Due to a lack of time (as explained in my Announcements 5 blog post) most of this has been copied off my analysis piece for Richland F1, with some added extras that I worth noting.

Shanghai is a bit of a tricky track to set the car up for as the corners are predominantly medium speed with long traction zones (especially the large banked turn onto the huge back straight), but there are plenty of straights to make up time on.

It is for these reasons that we tend to see a compromised aerodynamic package which will later be seen in races such as Canada, where the trade-off between downforce and top speed is constantly being assessed throughout the weekend.

The lengthy corners also put a focus on front tyre life, particularly the front left, so you can’t take too much wing off the car or else you risk putting the tyres in jeopardy. Even if you have slightly too little downforce the tyres won’t stay in their optimum temperature because the straights cool them down before the driver even reaches the braking zone – you could say that it is one of the toughest rounds of the year regarding setup.

To solve these problems teams bring upgrades, which are ideally more efficient at producing downforce than the outgoing component.

Mercedes

As promised by Mercedes, an array of new parts made their way onto the W06 right from FP1 after being beaten by Ferrari two weeks earlier.

W06 FW China

Front wing development has stabilised slightly over the past season but this new wing has once more upped the game by introducing an even more aggressive outboard region concept.

The elements – which remain at a total of six – arch aggressively at the extremities of the wing to form two distinctive sections: the inboard and outboard. The inboard is composed of the main plane which is split into two planes, and the upper two flaps and these are responsible for creating the Y250 vortex and controlling airflow around the front suspensions members.

Outboard, Mercedes have further expanded on the vortex tunnel design by almost isolating it entirely from the rest of the wing. The leading edge of the tunnel is shaped such that the air curls over on itself and accelerates. This coupled with the introduction of higher pressure flow through the slot gaps on the upper surface of the wing coils up the air to form a powerful vortex that is shed around the front tyre. This generates a huge amount of downforce and helps the endplates push flow around the front tyre too – the outwash effect.

These vortices tend to break up once they have come around the tyre as the turbulent wake behind the rotating wheel mixes with it and disperses. Contrary to popular belief these vortices never reach the Coke-bottle section of the car – the designers want to keep this area full of clean laminar flow to work the top of the diffuser, which is why we see the large vanes the hang off the shoulder of the sidepods to protect air passing through the ‘pod’s undercut.

Additionally, more tiny vortex generators on the individual planes of the wing were also evident. Again, this is to help air pass through the slot gaps and aid how the main vortex in the tunnel forms.

Mated with the new wing was an updated pair of front brake ducts. The previous large vane that hung off the guide plane of the duct has been deleted in favour of a more fluid-looking flick-shaped vane that branches neatly from the leading edge of the duct. This will work more favourably with the updated front wing.

As mentioned above, top speed is also important in China so a revised rear wing was also brought in. The wing has a slightly lower angle of attach and the wing tips cut triangularly to reduce drag.

Red Bull

Renault’s power deficit was always going to be more evident here than any other track so far in 2015 so Red Bull had a number of rear wing options to play with. A lower angle of attack version was used by both drivers during qualifying and the race, both of which feature their more intricate endplate design with the extended slot along the leading edge.

On the front wing, the Milton Keynes outfit have now officially departed with their long-standing endplate design in favour for a Mercedes-style solution, featuring a single fence with a small flick at the trailing edge to entice flow around the front tyre.

However the most important change Red Bull have made so far this year is returning to Brembo discs and calipers from China onwards, swapping out the Hitcos used since winter testing. The team opted to use Hitco at the start of the year following Sebastian Vettel’s feedback before he headed off to Ferrari, but cooling issues have resulted in them being ditched in favour of what they has last year.

The Brembos work like no other brake on the grid – they are not the most powerful but they are extremely consistent across the braking phase. However they also require less cooling inlets and are generally easier to manage than most of the other manufacturers out there, which is why we saw the issues the team had in Malaysia.

Swapping back to another brake supplier is pretty difficult, though. Daniel Ricciardo was having visible difficulty to stop the car during the race, which can be put down to the team not finding the sweet spot between the brake bias and the pressure versus the harvesting capabilities of the MGU-K. It’s more of a setup issue than an inherent car problem, so expect it to be addressed soon.

Sauber

C34 FW

Like Mercedes, Sauber also had a front wing/front brake duct update. The new wing is a quite the departure from its predecessor as the promising C34 begins to undergo significant development.

Designed during early 2015, this wing was meant to be introduced in Bahrain but it was fast-tracked thanks to funds coming through quicker than expected.

Whilst the cascade winglet remains very much the same as the last edition, the accompanying ‘r’ vane has been moved closer with a small aerofoil join sandwiched between them.

The wing itself has been upgraded from four to five elements, with a more conventional divide between the inboard and outboard sections similar to that of Mercedes. Metal clips have been formed into the carbon fibre at the inboard region to stiffen up the wing as it undergoes load, allowing for a more consistent formation of the Y250 vortex across a range of speeds.

It is worth noting that the flap adjuster lies on the inboard section. More commonly this housing is placed on the divide between the two regions as this is more aero neutral. However keeping the outboard segment cleaner can certainly benefit the overall outwash effect of the wing and is also slightly more efficient.

Lotus

Some subtle changes were made to the Lotus front end, minutely changing the aerostructures to suit components downstream.

The nose pylons were extended downwards at their base, removing the transitional step between the pylon itself and the wing’s mounting bracket to form a smooth profile for air to pass over.

This was accompanied by a small adjustment to the inboard flap section that is responsible for controlling the Y250 vortex. These were extended further inwards and curled down towards the main plane in a similar fashion to those on the Mercedes. However this this wing configuration was not raced on Sunday although expect it to turn up in Bahrain this weekend.

Williams

For all the raving about Williams’ front wing during the weekend, it appears as if it was just a minute alteration to the under-wing turning vanes that was the only visible sight of anything new.

But do not let that fool you so quickly. So much work is done through the layup of carbon fibre that has a dramatic effect on how the wing performs across all air speeds. Williams are one team in particular who are ‘bending’ the letter of law with some extremely flexible wing flaps, as evident on the onboard nose camera shot. Getting the wing to flex in a desired manner can be worth multiple tenths of a second per lap when working correctly. Expect this to be an underlying feature of the 2015 season as the designers run out of areas to play with.

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