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TECH TUESDAY: Mercedes and Ferrari approached by Baku's unique challenges

Azerbaijan was the first race of this season where they did not have their medium-downforce packages and instead moved to their low-downforce configurations. Not to the full Monza extent where everything is tremendous back for low drag almost no matter, but to the extent that the drag considerations are much more important than the three tracks before. The different way that Mercedes and Ferrari adapted their quite different cars was quite illuminating.

The evidence of the speed traces and corner speeds from the first three races suggested that the Mercedes could carry more downforce than the Ferrari, but that Ferrari had slightly lower drag. The two qualities are, of course, interrelated to large extent in that downforce costs drag; it’s merely a case of efficiency in the trade-off.

As they conceive their cars, the teams will pitch their aero efficiency ranges around the ballpark downforce figure they expect to be able to achieve. An aero efficiency target will be set around this figure and any pieces that add downforce while still keeping the car within that aero efficiency target will be acceptable. Those which only add downforce would be above the set target efficiency will be rejected. Where that efficiency number is set is a subject – but very well-educated – call.

2019 Azerbaijan GP
BAKU CITY CIRCUIT, AZERBAIJAN – APRIL 27: Charles Leclerc, Ferrari SF90 during the Azerbaijan GP at Baku City Circuit on April 27, 2019 in Baku City Circuit, Azerbaijan. (Photo by Jerry Andre / Sutton Images)

Mercedes, with their long-wheelbase car featuring a big underfloor area and great confidence in their power unit, has clearly felt comfortable defining a lower aero efficiency in their chase of downforce under the new 2019 aero regulations.

In the concept of their basic car, Ferrari has a set and higher aero efficiency target and has been able to justify extra downforce as easily. Hence the Ferrari being faster down the straights (helped by more potent high-power mode than Mercedes), but Merc's quicker through slow-speed speed corners.

In faster corners, the Ferrari's higher-rake underfloor delivers its benefits over the low-rake (but bigger-floored) Mercedes. The way this has been translated into lap time between the two cars has varied according to the layout of each track and how well they set-up got the sensitive tires into the correct temperature window. The car with more downforce will invariably tend to work the tires better than the lower-downforce car, incidentally, keeping the core of the tyre working harder without its overheating tread. The longer the corner, the greater the advantage.

But then we came to Baku and its schizophrenic layout, with the longest stretch of top-gear, flat-out running (27 seconds) on the calendar rewarding low drag but Monaco-like middle sector demanding high downforce. Over the years, the teams have come to their Baku to compromise in the favor of lowering the drag and bringing the family and front wings to those seen at the conventional tracks.

2019 Azerbaijan GP
BAKU CITY CIRCUIT, AZERBAIJAN – APRIL 27: Mercedes AMG W10 during the Azerbaijan GP at Baku City Circuit on April 27, 2019 in Baku City Circuit, Azerbaijan. (Photo by Jerry Andre / Sutton Images)

The conventional wings would be run at a very inefficient part of their working range at Baku (ie, the downforce penalty for reduction in their minimum settings would be too great). Instead, a different family of wings designed to work better in the low-drag part of the range are brought instead.

This applied to both Mercedes and Ferrari this year. But the way in which the Baku wings diverted from their conventional counterparts was quite different in the case of each car. Ferrari, with their inherently lower-downforce / drag car and small-winged front wing, used more than before, albeit with very flat settings. Mercedes, with their inherently higher-downforce / drag car and bigger-front wing element, used less wing area.

Ferrari SF90 front wing - Baku
The revised front wing on Ferrari's SF90

The evidence suggests that until the Ferrari track was taken out of the ideal temperature window (by delays in the crashes and red flags), the Baku layout was allowed to be used in the Ferrari aero into and beyond the Merc’s. The SF90 was faster down the long straight than the W10 and comparatively fast through the tight twists of the middle sector.

Only the cooling track and the lack of a powerful tow for Ferrari Mercedes to lock the front row. Before that – and before Charles Leclerc crashed in Q2 – the Ferrari snake and very clear edge. Even Sebastian Vettel – not as quick as Leclerc around here – with his tires not quite in the temperature window, lost on the field by only 0.2s over giving 0.3s of slipstreaming benefit that both Mercs picked up.

But the bridge tracks on the calendar demand more conventional aero packages and with the Baku family of wings likely not to be seen again, possibly until Montreal – and any differences in performance between the two cars will be based around how they compare in their medium- (or at Monaco, high-) downforce configurations once more. As such, the upgraded barge boards and the floor introduced by Ferrari in Baku, which are unlike the Baku-specific, will have more importance in the ongoing competitive struggle between the two teams.

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