When Mercedes launched its 2023 W14 there were a lot of comments about the return to a black livery. The base colour is that of the naked carbon fibre structure, with no paint applied at all. And the reason? To save weight.
Mercedes is not alone in stripping paint, or at least refraining from applying it in the first place, for this reason. But given the current minimum weight limit is a whopping 798kg, you may be left wondering how they can fail to build a car that can accommodate a few coats of satin silver. As always with cutting-edge competition, the answer isn't simple.
The need to reduce weight for racing was understood from motorsport’s very beginnings. But in those pioneering days, with relatively low speeds and only a basic grasp of aerodynamics among engineers, weight reduction more often than not simply meant discarding any bodywork deemed non-essential while drilling various components in strategic places. The advantage of reducing mass is directly linked to the fact that, as Sir Isaac Newton observed, a moving object will continue in a straight line unless a force is exerted on it. The greater the mass of your vehicle, the greater the force required to accelerate it, stop it or make it change direction.
One of the first applications of a weight limit in motorsport came about through the realisation that bigger, more powerful engines with their cooling and fuel systems are heavier than smaller ones. In the 1930s the rulemakers believed that if they wanted to limit speeds and expenditure then stipulating an upper limit for the weight of competing vehicles was a pretty handy way of doing it.
However, the governing AIACR soon realised the difficulty in this approach when it introduced the 750kg formula in 1934. The expectation was that this maximum weight limit would effectively result in engines of up to two litres only.
But a fresh approach, exotic materials and access to state funds allowed Mercedes to turn up for the new grand prix season with the 3.4-litre W25, and Auto Union with the 4.4-litre Type A. Both gained even more power by being supercharged.
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In a parallel to the present day, that Mercedes was devoid of paint to save weight, thus giving birth to the legend of the ‘Silver Arrows’. There’s a popular story that the paint removal was a last-minute fix for the cars being marginally overweight on debut at the 1934 Eifelrennen. But some suggest this was theatre concocted by legendary team manager Alfred Neubauer – the silver look goes back even further.
All engineering is a compromise but this is especially the case when designing cars to not only meet a weight limit (now a minimum one, of course) but also be as fast as possible over a set distance and within budgetary constraints. In crude terms, light is fast and agile, while heavy allows for a more powerful engine. Today the design process is complicated further by having to meet stringent crash tests, with the structures required being relatively heavy.
A good starting point for reducing weight is legendary Lotus founder Colin Chapman's mantra “add lightness”. If you can remove parts and the bits needed to hold them together while taking a general approach of removing mass wherever you can, then you will inevitably move towards having the lightest car possible.
You may wonder why, if there is a minimum limit, it’s commonplace that cars are designed to weigh even less than said limit. That’s because the strategic installation of ballast weights to improve balance and handling while just reaching the lowest weight permissible brings yet further improvements in lap times. Hence the presence of ingots of high-density material embedded in the front of today's cars.
New materials and technologies almost invariably bring the opportunity for reducing weight with them. Just as the aluminium monocoque introduced by the Lotus 25 was stiffer and lighter than the spaceframe that preceded it, so the composite chassis of the 1980s were stiffer and lighter still
All aspects of weight reduction need to be maximised for success and that includes the amount of fuel being carried for a race. Mario Andretti, among others, fell victim to Chapman's marginal fuelling policy at Lotus. The intention was that the car would just be able to crawl across the finish line, but in some cases it didn't quite make it. That led to considerable upset for the drivers concerned.
Toleman once took a more contentious approach. Desperately needing to make a performance statement at the 1982 British Grand Prix at Brands Hatch, the team deliberately under-fuelled Derek Warwick's car. He stormed from 16th on the grid to second with his artificially lightened car before inevitably running out of fuel. A broken driveshaft was officially blamed by the team for his having to take an early bath.
It wasn’t the day’s only demonstration of the dramatic difference that carrying less fuel can make. At the same race Brabham's technical wizard Gordon Murray introduced his somewhat more sophisticated plan to exploit the same advantage. Bad luck intervened at Brands and the next few rounds before, finally, at the Austrian GP, Nelson Piquet pulled in from the lead for a strategic fuel and tyre stop – not seen at the top level for years. Despite spending a whopping 20 seconds stationary, the advantage was clear. Refuelling during races would become a regular feature as rules allowed – until its most recent banning after the 2009 season.
New materials and technologies almost invariably bring the opportunity for reducing weight with them. Just as the aluminium monocoque introduced by the Lotus 25 was stiffer and lighter than the spaceframe that preceded it, so the composite chassis of the 1980s were stiffer and lighter still. Incidentally, those aluminium monocoques of the 1960s and 1970s were left unpainted for exactly the same reason as the W25's bodywork back in the 1930s and the W14 in 2023. They didn't need protecting against corrosion and therefore paint would only add weight with no advantage. Frank Dernie confirms this was the case when he was at Williams, where nothing was painted that didn't have to be.
The notable exception there was the FW07's rear wing main plane. This was one of the first major carbon fibre components fitted to a car and the colour of the exposed weave would have given the game away. Anything painted on an F1 car may be worth a closer look, in fact, because the reasons may go beyond the aesthetic or commercial.
Composite materials soon spread beyond wings, of course, with chassis tubs fabricated from individual panels before becoming integral moulded items.
Surprisingly it was ATS, a perennial underdog of F1 from 1977 to 1984, that was the first to make even greater savings by dispensing with separate bodywork around this central structural component. In 1983 its D6 became the first F1 car to use the outer surfaces of the tub as the external panels, possibly the most notable contribution made by the team in its eight years competing at the top.
This environment of single-minded optimisation can bring entirely unexpected hazards, as Ian Cowley, a young engineer at John Barnard's Ferrari outpost in Surrey during the mid-1990s, found out. A change in extinguisher foam to AFFF allowed a move from metal cylinders to composite containers, which were not only easier to integrate into the overall design but also seen as potentially giving the largest percentage weight saving for any system over the previous year's car.
Cowley designed Ferrari's new extinguisher ‘bottle’, which was then manufactured and filled under pressure in Britain. All went well until, on a cold day, a batch was stacked in the production manager's office – next to the radiator. The solder plugs that are designed to release the contents automatically in the presence of heat, presumably behaving differently by not having the benefit of being mounted on a substantial metal heat sink, did exactly that – with unfortunate consequences. The cry of “Cowley, you b*****!” alerted Ian and everyone else within earshot to the fact that the office was now steadily filling with foam.
Who knows where the next weight-saving gain will be made? Ultimately the only thing we can be certain about is that, as every team seeks to draw the maximum performance from its design, they will inevitably manage to just hit the allowable limit. And whatever ‘spare’ weight was available will have been used for a performance advantage. Because in such a competitive environment even a few grammes of paint is a wasted opportunity.
