Mercedes makes low downforce changes

Mercedes has gone beyond the usual low-drag set-ups of a small rear wing and trimmed front wing flaps for Spa. It has introduced a wide range of changes for the low-downforce demands of the circuit.

Starting at the front of the car, the nose is subtly revised. It is now more rounded and hooked, with a smooth curve over the top and an arched underside.

This creates more space under the nose for airflow to reach a new series of turning vanes mounted in this area.

These have now expanded to four separate elements and work with the bat-like wing under the nose, directing airflow back along the car.

Also at the front of the car, the inlet scoop on the front brake ducts has gained a small vertical fin.

At the rear, the top wing is all new. It features a dramatic arched trailing edge.

With the chord of the wing shorter near the endplate and the two slot gap separators, the resulting longer mid-sections of the wing work harder and should produce less drag from tip vortices.

Below the top of the rear wing is a similarly slimmed down monkey seat. Tested at Silverstone after the British Grand Prix, the winglet trails the wing-mounting pylons on slender arms and features a single small shallow flap.

With these drag-reducing features, the engine has not come in for further attention.

Both drivers have their fourth engine fitted for this weekend, as the track is power-sensitive. But Mercedes confirmed that these use the same specification as before.

FERRARI

As with most teams, Ferrari had a shallower rear wing to aid top speed at Spa.

A front wing was also trialled without the usual cascade winglets; instead the space is filled with another r-shaped vane.

Speed has not only been boosted by less drag, but also more power.

To achieve this, Ferrari has copied Marussia and lagged the exhaust pipes with heat protective wrapping. Whereas Marussia has wrapped its exhaust in bandage-like material, Ferrari has a shaped metal heat shield.

Both of these solutions are aimed at retaining more heat within the exhaust pipe. This keeps the exhaust velocity higher and in turn works the turbo harder for more power.

The wrapping covers the exhaust from the exhaust ports to the 3-into-1 collector. Then, after a small gap, they again cover the exhaust from the collector to the turbo inlet.

The small break in the insulation is to allow the exhausts to be disassembled. The thicker exhaust walls around the collector provide a greater degree of heat retention, lessening the negative effect of the gap.

It is understood this is allowed as the wrapping is not part of the exhaust system itself, which is confined by the engine specification freeze.

By contrast, a heat-protective coating that was sprayed on was considered part of the exhaust and prohibited by regulations.

McLAREN

One of McLaren's mid-season changes is to remove the upper mushroom fairing on the rear suspension.

Although this costs downforce, the reduction in drag offsets this. For the drag-sensitive Spa track, McLaren has further evolved its floor and rear suspension interaction.

There is still only one mushroom fairing, which is fitted to the lower wishbone. But the floor and diffuser around has been revised to suit the change in flow structure from the simpler suspension set-up.

Additionally the diffuser has a u-shaped exit added the centre section.

This is also a feature of the Mercedes, some of the airflow around the sidepods passes straight through the exit, which is believed to aid the car's balance.

Along with these bigger changes, the top rear wing is new and still sports the wavy slot gap, albeit with a much slimmer profile for greater top speed. Further reducing drag is the removal of the monkey seat.

FORCE INDIA

A small detail change for the low drag nature of the Spa circuit is a simpler monkey seat.

Rather than the full wing shape, the Spa set-up is an arched shape, through which the exhaust blows.

Most teams still play the exhaust plume over the winglet area, as this is allowed as long as the bodywork does not sit along the same axis as the exhaust tail pipe.

Being above and either side of this axis, most blown monkey seats are totally legal.

LOTUS

A multitude of upgrades have been fitted to the E22, the most notable of which is the change in the surfaces under the twin-tusk nose and raised chassis.

The lower edges of the nose/chassis previously formed a curtain-like vane. These have been removed and a triangular cut-out where the turning vanes are replaces them.

This creates a more open path for the air to exit under the nose, so this may be a low-drag specific set-up, rather than a permanent addition to the car.

MARUSSIA

With the late announcement of the ban of FRIC, or HPC as Marussia calls it internally, the team took the time before the August break to review its suspension set-up on the seven-post rig.

As a result, it has a new internal rear suspension set-up to match the now unlinked hydraulic front set-up.

It transpires that the heave control needed at the back of the car could be effectively provided by a front suspension component last used in 2010 being fitted to the rear suspension.

Due to time restrictions, the front heave set-up retains the full hydraulic actuator with its associated valves and accumulators.

This path has been taken for pragmatic reasons. A simpler and lighter version could be used, but the existing front suspension set-up is retained - merely disconnected from the rear suspension.

CATERHAM

With funding from the new management, Caterham has been able to invest in the start of an upgrade programme to the CT05.

This kicked off at Spa, with a visibly different nose, revised sidepod bodywork and a new floor. Not all the updates were on both cars, as Marcus Ericsson is running with a new monocoque, to replace the tub damaged at the Hungaroring.

Late to arrive, the new chassis is slightly lighter and has yet to be fully liveried, with bare carbon sections still evident.

What appears to be a new nose is, in fact, just a reworking of the non-structural vanity panel fitted to the actual front crash structure.

Previously, the black pronged nose was topped with an awkward looking wedge shaped section painted green. This green section was purely for aerodynamics and was only made of a thin laminate construction.

This new section is now more shapely and merges the nose tip and chassis more smoothly. It still, however, acts to direct more air under the nose to activate the horizontal turning vane under the front suspension.

This turning vane, the inner nose structure and front wing all remain the same spec as before Spa.