Why catching Mercedes will be a tall order in 2015 for F1's distant chasing pack

For all that we’ve enjoyed some great battles this year between Lewis Hamilton and Nico Rosberg, the hope must be that other teams can close the gap to Mercedes GP in 2015. But realistically, what are the chances of that happening?

The Mercedes W05 sometimes had a race pace advantage of 1.5s per lap over the competition. Even at its least competitive, it remained around half a second clear of the field. It’s now well understood how that pace was derived, but understanding it is one thing, replicating it something else. The advantage over the non-Mercedes-engined cars came from a power unit that began the season with something like a 70bhp head start and better fuel efficiency. This was why it was dominant even over the Red Bull RB10, the only car with comparably good aerodynamics. The advantage over other Mercedes-engined cars came from a clever way around the two most difficult challenges presented by the much more restrictive aerodynamic regulations of 2014.

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So in essence the RB10 and W05 were the only two cars that had nailed the new aero requirements while the Mercedes power unit was the only one to properly meet the challenge of the new engine formula. As the only car combining both, the root of the Mercedes W05’s dominance was clear. As to how those solutions had been reached by Mercedes, it was due to better planning, deeper research and more co-ordination and motivation of the engineering talent within the organisation. The engine, chassis and aerodynamic departments worked in a much more integrated and co-operative way than elsewhere, within a ‘brains trust’ structure that had been set up by Ross Brawn and Mercedes’ engine chief Andy Cowell.

That’s how it was done. But now that the result is known, how feasible is it for the competition to incorporate those technical ideas? In terms of the engine, the Mercedes’ power advantage was mainly mechanical rather than electrical. With its compressor at the front of the engine, out of aerodynamic harm’s way, it was bigger than the rear-mounted Renault and Ferrari compressors. This involved a very demanding engineering solution however, with the shaft connecting the compressor to the rear-mounted turbine (where it has to be in order to be turned by the exhaust gases) running the whole length of the engine. This shaft is limited in diameter by regulation, turns at over 120,000rpm and drives the ersH motor which sits in the middle. The slightest bit of flex would have disastrously destroyed the bearings of the ersH and possibly the compressor. Engineering such a long and fast-spinning shaft to have zero flex within it was not the work of a moment and took Mercedes around two years to perfect. The time involved in overcoming this challenge is believed to be what has caused Renault and Ferrari to be pushing for a regulation change that would allow a mid-season change of specification.

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With Mercedes consistently refusing to grant its blessing to this change and thereby thwarting the unanimous agreement needed, it’s looking increasingly likely that Renault and Ferrari will have to begin the season with developments of their current rear compressor designs.  Both have identified plenty of areas where they can improve those power units and the Renault step (of its rear compressor motor) is believed to be in the order of 70bhp – which would bring it up to around the 2014 Mercedes motor. But Mercedes itself will not be standing still and is expected to have an extra 60bhp more again. This is almost certainly what is behind the politics of Christian Horner suggesting a new twin turbo format for 2016 (when only a majority agreement is required rather than unanimous) – which would wipe the current Mercedes advantage. With that threat around, might Mercedes relax its stance on allowing Renault and Ferrari their mid-season upgrades? Around that hangs the question of just how close Renault and Ferrari can get to Mercedes horsepower and fuel efficiency next year. Then there is Honda, newly entered for 2015. It’s not yet known outside McLaren and Honda whether this new motor features a front or rear-mounted compressor, but regardless it would be surprising if a new manufacturer would be instantly up to the level of a year two Mercedes.

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Implementing the key of the Mercedes aero advantage might be less complex. Getting good downforce to both the front and rear of the car was incredibly difficult under the 2014 regulations. Having the front wings extend only about half way across the width of the front tyre - rather than being virtually flush with them as previously – hurt front downforce. Getting the air to flow around the tyre in such a way as to meet up and form a vortex (a circling current of air that can be used to accelerate the speed of the flow) in the necessary place became a very big challenge. Mercedes got around it by removing the obstacle of one of the lower front suspension’s arms. Instead of a conventional V shape for the lower wishbone, the Mercedes had just a single arm, with a forked end. Other teams had to generate front downforce by getting a diffuser effect from bringing the underside of the nose very close to the central section of the wing. But this limited the flow being fed to the underfloor towards the rear of the car. Mercedes, by being able to generate good front flow through its trick suspension arm, was able to keep the gap between the nose and the wing big – allowing more airflow through the underfloor and to the rear. Red Bull achieved it differently, but with a similarly aerodynamically effective end result.  

Making a single suspension arm strong enough to cope with the loads previously taken by two was another significant engineering challenge – albeit not one beyond pretty much any of the F1 teams. It wasn’t copied during the season as it would have involved changes to the whole tub of the car in order to have the mounting points and strength in the right places. But it could presumably be copied for next year. Expect to see a version of it on most 2015 cars.

The challenge of catching up in one move to a car that had two very significant areas of advantage while that team continues to evolve and develop its design are huge. Assuming there are no other radical game-changing solutions in the pipeline and that 2015 is about evolution, it would be surprising if the gap to Mercedes was not reduced – but even more surprising if it was overcome.

MH