There has been little to separate Mercedes and Ferrari as each has seized the initiative at various points of the campaign, with neither able to pull itself clear at the front.

What has perhaps been really fascinating is that the teams, with very different car philosophies, have been split by such small margins each weekend.

Here, ahead of the title battle getting going again, we look back with the help of Giorgio Piola's exclusive illustrations to reflect on their development progress and look at what could be the key factors that make the difference in the end.

Taming the diva

The Mercedes W08 was dogged by tricky characteristics during 2017, so much so that Toto Wolff had even coined the term 'diva' for it.

As such, some began to question the validity of retaining a long wheel base for its successor, with the car's length being viewed as a contributory factor to its weakness at certain tracks.

But technical director James Allison remarked its retention was a "no-brainer", with more to be lost than gained by following a new development trajectory, especially as Ferrari was in such close quarters throughout 2017.

Ferrari's aero gains

Many were shocked then, when Ferrari's 2018 challenger was unveiled and featured a similarly long wheelbase. The SF71H grew by over 700mm compared with its predecessor.

This was a decision driven by Ferrari's quest to improve upon its own weaknesses though, as Mattia Binotto explained.

"If we take stock of what we did last year, in low-speed tracks we always did well, while in circuits where the speed was higher we were suffering a little bit more [relative to Mercedes]," he said.

It would be unfair to attribute the W08's 'diva' moniker to just one factor though, as before the season even got underway a technical directive regarding suspension systems was believed to have wiped away an area where the team (and Red Bull) had an advantage over Ferrari.

The systems which carried some of the DNA of the previously outlawed FRIC system helped to improve the aerodynamic output of the cars. This new ruling appeared to hobble Mercedes, which had perhaps the most advanced system and was forced to carry that penalty throughout the season.

Adapting to change

For 2018, the team made some changes in this regard, as it slightly offset and interlinked the front suspension rockers, in order that the suspension could be more accurately controlled.

At the rear of the car, the team, like it did at the front in 2017, decided to raise the position of the upper wishbone. This resulted in an extension sprouting out of the upright (red arrow) and a raised inner connecting point (blue arrow).

Meanwhile, Ferrari took advantage of its extra wheelbase to make some changes around the rear of the car for aerodynamic purposes. This included a floor channel, used in previous Ferrari iterations down the years (SF16-H, left inset), improving flow around the cars coke bottle region.

Ferrari SF71H and Ferrari SF70H bargeboard comparison Photo by: Giorgio Piola

However, it was around the car's midriff where Ferrari planned on taking the biggest leap forward, perhaps even taking some cues from its closest rival, as it upped the complexity level of its bargeboards and the leading edge of the floor.

Slider List Ferrari SF70H side detail 1 / 4 Photo by: Giorgio Piola Ferrari SF71H side pods 2 / 4 Photo by: Giorgio Piola Mercedes AMG F1 W08 sidepod detail 3 / 4 Photo by: Giorgio Piola Mercedes F1 W09 turning vanes 4 / 4 Photo by: Giorgio Piola

Its sidepod solution, which had wowed the paddock in 2017 due to the lateral thinking required to achieve its overall design, was also able to be improved upon due to their new dimensional freedom.

Meanwhile, Mercedes pressed on with its more conventional sidepod layout, although in a video teasing the introduction of the W09, James Allison did wax lyrical about the improvements made by the team in this area of the car since last season.

Slider List Ferrari SF71H and SF70H front wing comparison 1 / 2 Photo by: Giorgio Piola Mercedes F1 W09 detail front wing 2 / 2 Photo by: Mark Sutton

Ferrari began the season with a new front wing philosophy, discarding the arched section next to the neutral section (arrowed, inset) and replacing it with slots in the same area (highlighted in yellow).

The shape of the outboard tunnel section was also revised, as the designers sought to alter the shape of the wake generated by the front tyre (comparison, left inset).

Mercedes revised its front wing endplate too, adopting a draped section at the rear (highlighted in green), altering how the airflow outwashes around the front tyre.

The development race

The manner in which a team introduces updates to its car during a campaign can be pivotal to the team’s overall success. This is even more crucial when two teams are fighting it out as part of a championship battle.

The following illustrations depict the development timeline undertaken by both Mercedes and Ferrari so far this season and, whilst not exhaustive, do offer an insight into the mindset of both teams.

Slider List Ferrari SF71H rear wing 1 / 11 Photo by: Giorgio Piola Mercedes F1 W09 rear wing Azerbaijan GP and Spanish GP 2 / 11 Photo by: Giorgio Piola Ferrari SF71H mirrors comparsion 3 / 11 Photo by: Giorgio Piola Ferrari SF71H mirros Monaco GP 4 / 11 Photo by: Giorgio Piola Mercedes F1 W09 Fronz suspension wing compare to Sauber C37 5 / 11 Photo by: Giorgio Piola Ferrari SF71H rear suspension comparsion 6 / 11 Photo by: Giorgio Piola Ferrari SF71H bargeboard, Canadian GP 7 / 11 Photo by: Giorgio Piola Ferrari SF71H front wing comparison 8 / 11 Photo by: Giorgio Piola Mercedes W09 front brake fins, French GP 9 / 11 Photo by: Giorgio Piola Ferrari SF71H floor and brake duct comparsion 10 / 11 Photo by: Giorgio Piola Ferrari SF71H floor 11 / 11 Photo by: Giorgio Piola

Both teams made their first major aerodynamic change in Azerbaijan, when the teams discarded their conventional shaped rear wings in favour of ‘spoon’ shaped variants - designed to reduce drag.

At the Spanish GP, a development waypoint for all teams given its a return to Europe, both reverted to their high downforce rear wing designs.

Ferrari, however, pushed the design envelope as it used some controversial halo mounted mirror supports.

Having already drawn intrigue with its unique two-piece mirror design that it had already been forced to make adjustments to in Azerbaijan in order to comply with the regulations, the new supplementary mirror supports were even more divisive, leading to them being banned from the next race onwards.

Mercedes added another small aero trinket to the upper arm of its front suspension, having seen the idea emerge on the Sauber (inset), which had itself converged on the Mercedes/Toro Rosso style high mounted wishbone arrangement introduced in 2017.

Ferrari had removed the upper winglet style mirror supports in Monaco, but they remained affixed to the halo, rather than the chassis.

More importantly though, Ferrari introduced a new rear suspension setup, which saw the upright arch made more pronounced for increased mechanical and aerodynamic performance.

Meanwhile, Mercedes added a cluster of vortex generators to the top surface of its sidepods in order to make it work harder at the lower speeds it would encounter around the principality.

Ferrari upped the ante in Canada, when it introduced a more aggressive bargeboard package and reorganised the slots in its splitter extension - an update that was even more potent than even the Scuderia first envisaged.

It followed this up with another long-lead item in France introducing a new front wing, featuring a full length slot in the mainplane. This altered the wing’s pitch sensitivity.

There was also a revised outer arched section and a new endplate canard configuration - both of which alter how the airflow moves across and around the front face of the tyre.

In comparison, Mercedes chose to stave off the introduction of any serious aerodynamic development parts, with only a small change made to one of the front brake duct winglets.

This was in-part due to the arrival of its second generation power unit, which had originally been planned for Canada but was delayed due to reliability concerns.

In Austria, Mercedes unveiled its largest update of the season, altering the shape of the sidepods in order that the inlet be pushed back. This helped lessen the impact that the front tyre wake can have on the flow around that area of the car.

The mirrors and their mounting stalks were also adjusted in order to suit the new bodywork and take advantage of any secondary aerodynamic effects that were on offer.

It also introduced a new rear wing, which featured an endplate design reminiscent of the one used by McLaren since 2017, increasing the wing's yield at higher downforce circuits.

Ferrari responded at Silverstone, as it introduced a new floor, featuring another full-length slot on the floor’s edge that blended into the angled ‘tyre squirt’ holes ahead of the rear tyre.

The intent was to ‘seal’ the edge of the floor, creating a sort of air skirt that encloses the airflow under the floor and diffuser. It also amended its rear brake duct winglet, fully separating it into three sections, rather than just having slots in the end fence.

Nine to go…

As we can see, both teams have chosen very different development paths in the opening part of the season, with Mercedes opting to plow resources into a larger update in Austria, whilst Ferrari has constantly thrown down with fairly sizeable updates of its own throughout.

This begs the question: who has the most left in the tank for development in the latter part of the season?

The situation will be even more intriguing as the glidepath for work on the 2019 car will need to be extended more than last year because of the impending change in regulations aimed at helping boost overtaking.