2017 ItalianGP: technical insight into Ferrari’s SF70H performance. The unique nature of the Monza track did not suit Ferrari's SF70H car.

Scuderia Ferrari had a difficult weekend in front of its own fans, as the Maranello team was not able to successfully challenge Mercedes’ Silver Arrows around the Autodromo di Monza last weekend. Due to the unique nature of the Italian Grand Prix venue, last weekend’s technical novelties mostly comprised of low-downforce packages. f1i.com has reviewed Ferrari’s SF70H performance as compared to the other Formula One teams:

LOW-DOWNFORCE ALL THE WAY
Like all other teams, Scuderia Ferrari chose to use a ran a low-downforce configuration and a low-drag rear wing at the Temple of Speed in order to generate healthy top-end speed, which is an absolute must at the Italian Grand Prix. Monza-spec rear wings have a lower angle of incidence, which means they are less tilted and sit higher than usual, while the upper flaps are slightly shorter.

The main board sports a flatter outline, i.e. the speed differential between the air above the plane and the air underneath it is less important. This in turn lowers the pressure differential on both sides of the wing (hence the lower downforce levels) but also the airflow separation (hence the lower drag levels). What’s more, the lower pressure differential between the two sides of the end-plate results in weaker wing-tip vortices, thus reducing the need for end-plate slits. These are absent on the Red Bull and Force India designs for instance, while there were fewer apertures on the Ferrari and Renault versions.

Monza-spec wings can be divided into three groups. The first one includes the Ferrari, Force India, Sauber, McLaren and Red Bull designs, which feature a main board with a flat outline.

ADAPTATION RATHER THAN REVOLUTION
The second design philosophy sticks to a curved plane, though it is less tilted, with Mercedes, Renault, Williams, and Toro Rosso going for this option. Monza-spec rear wings are expensive one-off endeavours, bearing in mind that the case housing the DRS mechanism has to be re-designed while the front wing must be changed as well in order to keep the aero balance of the car.

Formula One teams often bring several versions of their rear wings to Monza and use Friday’s free practice to sample them. One of the deciding factors is the impact each design has on tyre wear. Toro Rosso, for instance, trialed a rear wing with a flat board but eventually elected instead to race one with a curved, spoon-shaped plane.

TRYING TO STEER AWAY FROM TROUBLE
After finishing in the third place at the Monza track and some way behind the Silver Arrows, Scuderia Ferrari’s German driver Sebastian Vettel explained that he had suffered from a steering issue in the final 20 laps of the 53-lap Italian Grand Prix: “I went off in Turn 1 and I think something broke in the car. The left-hand side of the steering was a bit down and I couldn’t trust the car, especially on braking and it is a braking track. So the last laps I don’t think they showed the pace we could have gone. I think we probably lacked something like half a second per lap today but there’s not all the parts of the race you can judge. I am not worried too much about the gap. As I said before, Monza is a specific place. If you have that extra bit and confidence then it makes a big difference.” – Sebastian added.

If the problem is confirmed, then it will not be the first time this season when Sebastian Vettel’s progress has been hampered by a handling issue. It was already the case in at the 2017 Hungarian Grand Prix, where the Ferrari ace was on the back foot right from the start, though this did not prevent him from winning the race given the track characteristics of the Hungaroring circuit.

NEW BATTERY FORMAT
The format of the battery mounted on the SF70H has changed compared to the previous model. The 2017-spec energy store seems higher and narrower than its predecessor. The element sits below the fuel tank, a standard placement across all Formula One cars.

As a reminder, the energy recovery systems (ERS) include four elements: the MGU-H, the MGU-K, the battery or energy store, as well as a pair of control boxes. MGU stands for motor-generator unit. When acting as a generator, the device converts the mechanical and heat energy it receives into electrical energy. When operating as a motor, it is the opposite. The current 1.6-litre V6 turbocharged power units feature two MGUs: the MGU-H (for heat) absorbs power from the turbine shaft to convert heat energy from the exhaust gases, while the MGU-K (for kinetic) recovers some of the kinetic energy dissipated under braking.

The battery stores the energy recovered and collected by both MGUs. Looking at the diagram available in Appendix 3 of the technical regulations, the energy store can feed up to 4MJ/lap to the MGU-K, which then transfers a maximum power of 120kW to the drivetrain. However, the battery can only receive 2MJ. So in order to deliver the maximum 4MJ, the energy store benefits from the contribution of the MGU-H, which serves a dual purpose: charging the battery and supplementing the MGU-K (without any restriction). The energy store is made up of many lithium-ion cells and manufacturing a battery with that kind of storage capacity in a compact, low-weight (20 to 25kg) format is a true engineering challenge. Like the engine, the device must be pre-heated since it has a narrow operating temperature window.

WAITING HORSE
Unlike what it did last year, Scuderia Ferrari did not introduce a new engine spec for its home event, while Mercedes had done so a week prior at the Spa-Francorchamps circuit. The Scuderia’s fourth internal combustion engine (ICE) could be introduced in Malaysia, provided it passes various reliability tests. According to several sources, these would not be entirely satisfactory yet.

It remains unclear whether the engine received by Haas at Spa-Francorchamps prefigured the evolution, though it is more likely that Romain Grosjean and Kevin Magnussen only had another model of the same spec. Indeed, works teams usually get priority status over customer outfits when it comes to upgrades.

HIGH-PRECISION MEASUREMENTS
Among the measuring devices always used on Formula One cars, the Pitot tube is attached to the front end of the chassis. The image above, which was snapped last weekend, shows a Ferrari mechanic calibrating the element in the garage. It is not unusual for teams to add a second sensor in free practice for more precise measurements.

The Pitot sensor involves Bernoulli’s principle whereby airflow velocity is determined by measuring pressures. It is made up of two tubes, one for the static pressure, the second one for the overall pressure, which increases with speed. A pressure gauge measures the pressure differential between the two tubes (dynamic pressure), which is then used to determine airflow velocity around the sensor. With the car moving the air as it goes forward, the sensor is not as accurate as the sort of high-mounted devices often seen in winter testing. The pressures are then collected in a transducer via a series of thin and transparent plastic tubes.

Combined with other speed measuring devices (including one fitted on the wheels), the Pitot sensor indicates whether the car is experiencing headwind (the Pitot speed is then higher) or tailwind (the Pitot speed is lower).

It is also worth mentioning that McLaren and Toro Rosso mounted Pitot sensors inside the airbox of the MCL32 and STR12 when they ran the Halo cockpit protection system on Friday, this in order to measure the device’s impact of airflow circulation towards the engine.

ASYMMETRICAL BRAKE DRUMS
Several teams, including Scuderia Ferrari, decided to use asymmetrical brakes drums (the carbon casings that house the braking system) at the front in order to cool down the left tyre in a different manner as it takes most of the stress around the Autodromo di Monza. One can note that the left brake drum had been more closed off on the SF70H car.