Tech: F1 teams surprise in America

The Formula 1 teams brought a surprising amount of new parts to Austin this weekend for the United States Grand Prix.

For the all the new parts seen on the cars in the first free practice session on Friday, the underlying story is that teams are slowly converging on similar aero concepts, rather than lots of innovation being apparent.

This is not yet the end of the second year of the current regulations, and there are several areas of commonality between the cars. This weekend the front wing has been a focus and all the teams with R&D budget available have arrived with a similar concept.

This is known as the outswept wing. When the front wing dimensions were narrowed last year, most teams ran the wing profile as wide as possible, using the endplates to sweep the aero wake around the outside of the front tyre.

Now teams are running straighter endplate set-ups, but curving the front wing outwards, from a narrower leading edge to a wider trailing edge.

FERRARI

There were a plethora of new parts on the SF15-T, from the engine to the aerodynamics. Both cars were fitted with fresh engines, albeit with only minor reliability updates, contrary to the expectation that a 2016 development power unit would appear this weekend.

On the aero side, the car had updates front to rear. Ferrari fitted a completely new front wing, similar in principle to the previous outswept wing, with subtly different shaping.

Key differences were the pair of flaps, with no longer a join at their inner tips, and a new strake was added inside the endplate.

More striking was a change in front turning vane philosophy from Ferrari. Previously, simple hanging vanes were used, but now the bodywork under the front suspension mimics Mercedes.

The car has larger vanes, each fitted with a footplate running along the bottom. Behind this a Mercedes-style 'bat wing'.

Mercedes introduced this last year and it has not been copied by anyone until now. The winglet points downward so it's not acting to directly add downforce, but as a flow control device, flattening the front wing's upwash and directing it around the flanks of the sidepods.

At the rear, the unique winglet-like treatment to the top corners of the diffuser came in for more revision. The previous set-up had a small, two-element wing profile fitted to the corner of the diffuser, but now the winglet is merged with the flap running along the top of the diffuser, and forms four wing profiles stacked one on top of the other.

RED BULL

Electing not to run the updated Renault engine here, Red Bull retained effectively the same spec power unit as it has had since the season-opening Australian GP, aside from the reliability updates added through the year.

In common with almost every other team, Red Bull had a new front wing, following Mercedes' lead with an outswept design. This is a major change in philosophy for the team, which has not been known to follow other team's trends.

Unique to the Austin wing is the front flap adjuster. After problems with the stiffness of the old adjuster last year at Abu Dhabi, the 2015 wings have run a much simpler adjuster pod above the wing.

Now the adjuster sits in a teardrop-like pod high above the wing, mounted tripod-style with two thin legs supporting it to the front wing, and a third leg being the threaded adjuster, joined to the moveable wing section.

Making this delicate set-up stiff enough to pass FIA deflections tests must have been a challenge for the team's designers.

As well as inspiration taken from other teams for the front wing, the car also gained two small fins on the rear impact structure, again a design led by Mercedes and also followed by Ferrari.

MCLAREN

The updated internal combustion engine and exhausts from Honda, first tried in Russian GP free practice, returned to Alonso's car here, while there has also been effort on the chassis side from McLaren.

Whereas before the exhausts followed the Mercedes 2014 log-style set up - where the exhaust ports blow into a very short primary pipe, which then merges with a much larger secondary pipe leading straight to the turbo's turbine housing - they now follow a more conventional multi-branch tubular set-up. Far longer primary pipes meet at a 3-into-1 collector before a short pipe joins to the turbo.

With this change comes a different engine note. The Honda already sounds coarse and noisy when on part throttle, this being part of the anti-lag turbo strategy. It's thought this cylinder-cutting approach may be robbing the engine of power and the ability to recover energy from the turbo. Now the engine sounds less aggressive, but still the engine note is instantly discernable from the others on track.

McLaren also introduced an outswept front wing, the set-up following the older wing's cascade arrangement but with the endplate area changed to suit the narrower width.

In front of its rear wheels, the MP4-30 has taken Ferrari's slotted floor concept but gone even further.

While Ferrari has eight edge slots and a couple of 'L' shaped slots, McLaren has ditched its four 'L' slot set-up and added 11 edge slots, retaining two 'L' slots directly in front of the rear tyre. These slots blow a jet of air under the floor, along the inside face of the rear tyre. This offsets the wake coming off the tyre and upsetting the flow into the diffuser, which would rob the diffuser of downforce.

Smaller changes have been made to the rear brake ducts and exhaust position, but more influentially the car is being set up at a more extreme, Red Bull-like raked attitude - the rideheight being much higher at the rear and lower at the front.

This set-up creates more downforce once the problems of splitter floor clearance and sealing the diffuser have been solved. As part of this idea, the front wing and splitter can contact the ground when being dropped from the jacks at pitstops, potentially damaging the parts, so McLaren has been running tests with the car monitored by cameras as it is dropped from the jacks, to see if there is a problem with clearance.

MERCEDES

The W06 features a revised throttle damper, following the failure of that part on Rosberg's car at the Russian GP, but there are no other visible updates on the car for the Austin race.

However, the team did run a test in advance of the Mexican GP, fitting a revised cooling layout to Rosberg's car in first practice.

As Mexico City is at a higher altitude, the air is thinner, which affects both the engine's power output and also the efficiency of the cooling system.

To counter this Mercedes fitted a new duct set-up over the engine. The package comprises three parts: the top bodywork, a duct and an auxiliary cooler.

The duct starts at the roll hoop, with two side inlets, and leads back to the rear of the car, where a small cooler is fitted behind the existing large ERS radiator.

It's not clear exactly what this solution is cooling. Pipework leads down around the gearbox, so it could either be a gearbox oil cooler or a supplementary cooler for the ERS.

WILLIAMS

While there may have been undetectable changes to the rear bodywork and heat shields, the big visual difference is a new front wing on the FW37.

Again the main change is to the outer section of wing and the endplate, further developing the outswept aero concept adopted by the team mid-season.

TORO ROSSO

Again we saw the team run the supplementary air intakes around the roll hoop, first seen in Russia.

These lead back to a cooler mounted atop the gearbox. As with Mercedes, this is likely to be a Mexico development, in order to maximise cooling and reduce losses from inside the engine's airbox.

FORCE INDIA

Pressing on with its aero programme with a 50 per cent model inside the Toyota Cologne windtunnel, the team brought its third front wing iteration to America.

Unusually, Force India had all three 2015 specifications on hand at the track, with the new wing following the Silverstone 'B-spec' design, but with revised endplates.

It's interesting to note the bottom of the endplate is chamfered slightly. This is a Red Bull idea, where the car's nose-down raked attitude requires the leading lower edge of the endplate to be lifted to prevent it getting too close to the ground.

This is a further sign Force India is also going for a more extreme raked attitude with its current car.