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What Makes The 2015 Ferrari Different
Ferrari's restructure has had tangible results on track, in the team atmosphere and in its design philosophy. CRAIG SCARBOROUGH analyses how the SF15-T stands out from both its rivals and its predecessors
As Ferrari drifted through 2014 with poor results, massive changes were under way at Maranello.
While the overhaul of team management was perhaps most significant to the resurgence that followed, Ferrari has also made a step change in its car design, this year's car being significantly different to its predecessors.
It now seems the team's internal structure has allowed the different technical departments to work in unison, and that a big factor in the improved 2015 form is that the power unit and chassis are both integrated and complementary to a far greater degree than in 2014.
Power Unit/Gearbox
While Ferrari's new chassis clearly offers a handling improvement over the old, a significant proportion of its performance gain comes from the power unit and its packaging.
Last year's introduction of the new 1.6-litre V6 turbo hybrid engines led Ferrari to develop a power unit that compromised horsepower to facilitate a better fit in the chassis. But the chassis did not overcome the lack of power in 2014.
Ferrari has reversed the chassis/power-unit compromise, aiming not only for more outright power, but also improved driveability and more contribution from the ERS-H (heat) in the race.
The 2014 package produced an aggressive power delivery and ERS-H was largely used to provide extra boost in qualifying; the wastegate was run partly open to reduce back pressure. This left it lacking electrical energy to power the MGU-K (kinetic) in the race.
Outwardly, the power unit looks little different to last year. The exhausts have been shortened and the oil tank moved to the front of the engine. But its aims have been met and the motor is challenging Mercedes, although it is still short on power and fuel efficiency compared with the all-conquering Mercedes unit.
The carbonfibre gearbox case has been reshaped in the bellhousing area. Last year, this area was open to contain the turbo, such that the front of the case formed an open 'U' shape rather than a closed 'O'.
The turbo remains within the gear case, but the case now passes over the turbo to close the front into a hexagon-like shape. This makes the case stiffer, owing to the enclosed form, and the turbo exhaust pipe also gets a smoother run. It now passes through an aperture halfway along the top of the case. This less-contorted exhaust pipe releases more power.
Retained from last year is the water-cooled intercooler. This sits in the V of the engine and cools the air compressed by the rear-mounted turbocharger before entering the engine's inlets. This is a neat set-up, saving space in either the sidepods or fuel tank areas, but it does compromise the inlet design.
This design adds a small but significant issue with the new engine, in that it does not run variable-length inlets - making Ferrari the only team not taking advantage of the concession to use these in 2015. Variable-length inlets improves the power unit's driveability, and for Ferrari to adopt these a lot of tokens will need to be spent to alter the inlets and the intercooler design.
Ferrari has a healthy amount of development tokens left to use during the year and so far has had excellent reliability. Mercedes chief Niki Lauda is among those suggesting the Ferrari power unit is now nearly a match for Mercedes in peak horsepower terms. The development race in this area will hot up later this year as these two manufacturers start to add power-unit performance.
Sidepods & Radiators
Ferrari has made big gains here. Since the modified engine package creates more power, and therefore more heat, the radiators must be larger and cannot be vertically mounted as they were in 2014.
In order to package the radiators in a flatter position, Ferrari had to solve the problem of how to make the horizontal cooling airflow turn 90 degrees to pass vertically through the heat exchanger, and then turn again to exit the sidepods.
Rather than use large ductwork to turn the airflow, which would add bulk, Ferrari has chosen to use a series of small vanes under and over the radiator surface to redirect the air. This ensures airflow distribution over the radiator cores is consistent, and that the outer sidepod shape can be made as small as possible.
With the Barcelona update, this radiator set-up allowed a dramatic shrinking of the fronts of the sidepods. The outer shoulder of the sidepod has been lowered in line with the side impact structures, freeing up airflow over the engine cover to improve the performance of the rear wing and diffuser.
Rear Wing
Ferrari has experimented extensively with rear-wing endplates during the past two years. The rules dictate that the endplates must meet a large minimum cross-sectional area, which means they obstruct airflow under the wing and around the rear wheels.
As with most others on the grid, Ferrari's vertical leading edge has a pair of slots to improve flow through the wing. There are also vanes along the endplates' lower edge to turn the air behind the rear tyre to reduce drag.
But Ferrari has added a series of louvres. This passes airflow upwards from inside the wing to the area behind the rear brake ducts. It's common to shape the rear brakes to act as wings, and as a result they create an upwash. It appears Ferrari has added these louvres to aid the upwash effect and allow the rear ducts to create more downforce.
Front Wing
Ferrari launched the SF15-T with an incredible eight-element front wing, but this was subsequently replaced during testing with an ostensibly simpler one. In fact, this wing created even more complex airflow structures, but with less physical complication.
The key areas of the front wing are the outboard sections (marked in black), which are segmented from the inner sections of the wing. These are the hardest-working sections of the wing and are shaped to throw their wake outboard of the front tyre. This improves the airflow downstream. Mercedes has its own, more aggressive, interpretation of this segmented outswept wing.
Ferrari also runs a different nose layout to most other teams, with a long snout mounted to a downswept chassis front. According to technical director James Allison, this makes it difficult to engineer a short nose.
But there are still suggestions that a shorter nose will appear, although it's debatable whether the effort needed to manufacture and crash-test a new one will be worth the performance gain.
PULLROD FRONT SUSPENSION
The suitability of the pullrod front suspension is much debated. It involves the actuating rod pulling the springs and dampers rather than pushing. This means the rod is reversed from the conventional position, passing from the top of the wheel to the bottom of the chassis.
In this position, the pullrod works better for aerodynamic gain because it cleans up the brake duct area and sits in a position to control the front-wing wake.
It's often believed that the different rod position creates problems with suspension geometry, meaning it works the spring and dampers in a different way, but this is a fallacy.
Ferrari has proved the pullrod works without compromising front-end grip, although this year it did need to stiffen the wishbones and pullrod to get the best performance out of it.
Barcelona Update
These changes appear to be aimed at the flow along the flanks of the car, from the front-brake duct gaining new vanes to direct the front wing's wake around the inside face of the wheel, to the bargeboard with several slots to swirl the airflow through the undercut in the sidepods.
Around the rear tyres a new series of three slots in the floor ahead of the tyre reduces the amount of the tyre's wake entering the diffuser, then behind the tyre a tiny two-element winglet was added to the outer edge of the diffuser.
Ferrari was unsure if this massive update was working as well as expected after the opening practice sessions. Barcelona, despite being the most familiar track to the teams, often brings up rapidly-changing track conditions due to sun affecting track temperatures and wind affecting downforce in the corners.
Thus the Scuderia split its cars between new and old set-ups. The poor performance from Kimi Raikkonen in the race was suggested by his race engineer Dave Greenwood to be a result of the differing packages.
In testing this week the team retained its new aero set-up and it appears its introduction is a positive step overall. It can be expected to form the base of Ferrari's summer campaign at the European tracks.
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