Bahrain F1 test tech round-up

Last week's Bahrain Formula 1 test remained focused on understanding the new power units as teams try to resolve ongoing issues, and mapping the aero set-up of the original launch-specification cars.

But amid the painstaking work, there were some eye-catching new developments as some of the hidden details of the cars started to emerge.

RED BULL

Red Bull's power unit integration problems remain top of its list. Thermal issues are at the heart of the team's difficulties, with both the energy store (battery) and turbo being subject to on-the-hoof development to keep temperatures under control.

Such is the scale of the issues that quick fixes of a type now rare in F1 - and certainly un-Newey-like - were being applied to the RB10.

At Jerez, a makeshift cooling outlet was cut into the sidepod's Coke bottle area. For Bahrain, the solution was reversed with some convoluted tubing taped in place to feed air into the sidepod area.

MERCEDES

Upgrades for the second test included a new horizontal turning vane mounted under the front suspension. Surprisingly, this mimics the Caterham design, although Mercedes also ran more conventional turning vanes.

The new vane shares its mounting with the road speed sensor pod and forms a flat wing with downturned tips. It's these tips that do the work, creating a vortex that's directed at the sidepods' leading edges.

The changes are all part of the complex flow structures set up at the front of the car to make the underfloor and diffuser create more downforce.

Also on the car were a variety of sidepod cooling outlet options, including add-on panels to the flanks of the sidepods to create more cooling area, and also a top body section with a very large rounded outlet around the exhaust tailpipe.

This latter, more extreme, solution was only run briefly and will be Mercedes' contingency for extra cooling if temperatures at the opening races are higher than expected.

McLAREN

Like Mercedes, McLaren also tried different cooling configurations, still based around the large double-barrelled outlets seen on the launch car.

For Bahrain, these were modified with either a large gurney flap around the outlets or a series of six slots cut into the bodywork. The gurney solution is a simple means to pull more hot air from within the sidepods, one often used by teams at hot tracks.

The fishbone-like slots are another ploy used to create more cooling outlet area, but stretch the rules on sidepod openings.

The regulations allow for openings for each suspension member to pass through. These are relatively generous, but must each be a single opening and no other 'holes' are allowed in the sidepods, so the teams extend the suspension opening via a thin slot into three adjoining slots.

As there is just one opening, even if at some points it's a simple saw-cut thickness wide, it counts as a legal single opening.

McLaren continued to run the rear suspension fairings seen at Jerez, but what were 3D-printed prototype fairings have now been replaced with carbon fibre items. This suggests McLaren's initial test of what it's calling internally the 'mushroom' suspension was successful.

Although its full legality will not be proven until it's either scrutineered or protested in Melbourne, it's looking likely that it will make it onto the car for the first round.

Spy pictures of the McLaren power unit installation have appeared on the internet, showing the car from behind without the top bodywork. Although largely shrouded in heat shielding, some detail was visible.

Curiously for McLaren, given its relatively big sidepods featuring large inlet and outlet areas, the car also mounts two coolers above the power unit. One smaller cooler is fitted above the fuel tank and is fed by the inlet below the main rollhoop inlet.

In recent years, McLaren has mounted a KERS cooler in this position, so it's likely this is also for cooling the 2014 ERS installation, although this alone is not enough to cool the energy store, MGUs and ERS control units. Additional coolers are probably located in the sidepods.

Another larger cooler is mounted above the gearbox, close to the turbo, and appears to be fed from the top section of the split rollhoop inlet. Due to its location, it's possible this is the gearbox oil cooler. The remaining inlet in the rollhoop will be for the fresh air feed into the turbo.

This complexity of engine/power unit installation is one of the reasons teams are finding repairs and maintenance are taking longer than with the old V8s.

FORCE INDIA

Force India, with its Mercedes engine installation, appears to have used the rollhoop as a means of feeding air to a small ERS cooler. The team has both a rollhoop inlet and a piggyback inlet above and behind it.

Typically on a pre-2014 car, the larger rollhoop inlet would feed the engine with air and the piggyback would feed a small cooler. This situation appears to be reversed: because the turbo 'sucks' in air more effectively than a normally aspirated engine, its need for a large inlet is reduced.

On the Force India, the larger inlet is ducted downwards to feed what appears to be a small cooler for the ERS, while the piggyback routes back to the turbo via an air filter panel.

There's no immediate performance gain from this - it's just a neat packaging solution.

SAUBER

Only Sauber brought a major new aero package to Bahrain, the car sporting new wings and parts missing from the spec run at Jerez.

Even though the Jerez front wing was new, it was still based on a design first seen in Japan in 2012. Sauber's new front wing in Bahrain was a completely new design, with a different series of slots in the main plane.

The old wing was distinctive for its S-shaped slot gap between the main plane and flaps; the new one is more conventional, with a straighter gap and a pronounced upcurve where the multi-element wing meets the neutral centre section.

This area is crucial in forming the Y250 vortex that separates the front tyre wake from the clean airflow passing along the centreline of the car.

Along with the new front wing were the sidepod vanes missing at Jerez. There are two elements on each sidepod: the vertical vane and the bow-shaped horizontal vane over the sidepod.

Unusually, the vertical vane is attached to the sidepod with a very thick-section mounting. Why the team has used such a large mounting is unexplained - perhaps it'll be opened up to form a cooling outlet?

Finally, the C33 sported a new rear wing. Its leading edge features slightly downturned edges, which makes the outer span a steeper profile for more downforce.