Lifting the lid - Formula One helmets uncovered 31 Jul 2009
Before last Saturday at the Hungaroring, helmets only really made the headlines when a driver decided to sport a new livery or auction one for charity. But Felipe Massas dramatic accident during qualifying for the Hungarian Grand Prix brought driver safety - and in particular the great strides made in helmet design over the past few years - into much sharper focus.
Back in Formula One racings early days, it was speed, not safety that took precedence. Legendary world champion Juan Manuel Fangio preferred to race in a simple balaclava. But by 1953, even Fangio couldnt hold back the tide, and helmets were made compulsory. Ten years later the regulations would demand drivers use unbreakable, full-visor helmets. The ones used nowadays, however, bear little resemblance to their primitive predecessors and are the product of years of research and development.
As with all aspects of the sports safety, the FIA sets the standard, and the governing bodys most recent evolution of their helmet regulations, FIA 8860-2004, was developed over an eight-year period. Drafted by UK testing facility, Transport Research Laboratory (TRL), the new criteria were adopted by the three main Formula One helmet manufacturers, Arai, Bell and Schuberth, and the resulting homologated helmets were made compulsory by the World Motor Sport Council in 2004.
Although the exact composition of the materials that make up a Formula One helmet is a secret closely guarded by the manufacturers, the rigid outer shell features a couple of layers, usually fibre-reinforced resin over carbon fibre. Underneath, there is a layer of aramid (also used in many bulletproof vests) and another much thicker layer of polyethylene, a soft and deformable material, which is covered with the same flameproof material used in drivers overalls. Smaller quantifies of aluminium, magnesium and the binding agent epoxy resin are all added to the mix too.
The typical weight of a Formula One helmet is a remarkably minimal 1250 grams. The lighter the helmet, the less weight it adds to the drivers head under extreme G-forces, which in turn lessens the risk of whiplash-type injuries when something goes wrong. But as Massas accident in Hungary so dramatically demonstrated, a helmet also needs to be super strong, so it can absorb impacts and resist penetration during a crash.
With these (somewhat incompatible) aims of being both tough and lightweight, its no wonder the effort that goes into crafting a helmet that can fulfil the FIAs demands is immense. First, the drivers head is scanned to create a life-size model. This sculpted replica is then wrapped, layer by layer, with 120 mats of high-performance carbon fibre to ensure the perfect fit.
With every thread of fibre consisting of about 12,000 microthreads, each of which is about 15 times thinner than a human hair, the process is as expensive as it is cutting edge. In one helmet, the total length of all the threads is approximately 16,000 kilometres. Over the same distance you could drive from Tokyo to London.
The individual layers are then bonded together in an autoclave (a type of industrial pressure cooker), hardening under high pressure and at a constant temperature of 132°C. In addition, the parts which will be subject to huge loads once the helmet is in use, like the visor cut-out, are reinforced with supplementary materials, like aluminium and titanium.
As well as fulfilling its primary role of protecting a driver, the helmet must also allow him to see and breathe. Ventilation is provided through a small intake at the front, which filters the air to clean it of any motor oil, carbon and brake dust particles. Up to 10 litres of fresh air flow into the helmets interior per second.
The visor is made from a three millimetre-thick piece of specially-devised clear polycarbonate. Combining excellent impact protection, with flame resistance and excellent visibility, its by far the best solution. Most drivers tend to use tinted visors, which are coated with anti-fogging chemicals to prevent them misting up. In addition, there are several transparent tear-off strips attached to the outside, which the driver can remove as and when the visor gets dirty.
With equally strict safety standards to live up to, helmets are tested just as thoroughly as the cars. Fitted on an imitation metal head, and equipped with sensors that measure deceleration, the helmet is mounted on a sledge running on vertical track. To replicate an impact, the helmet (and head) are then lifted to a specified height and dropped on to a variety of objects, including a flat surface, a sharp edge, and a half-sphere.
The helmet test facility at TRL boasts a drop tower over 15.5m tall, which is capable of accelerating objects through gravity by up to around 17m/s (63km/h). A helmet designed to meet the FIAs 8860 standards needs to withstand an impact of 9.5m/s (34.2 km/h). At this speed, the sensors must never display a deceleration of more than 300g, while 225 joules of energy must be dissipated.
In line with the regulations, helmets also undergo a variety of further deformation and fragmentation evaluations, as well as procedures to test the HANS device, which prevents a drivers head from hitting the steering wheel. Theres also a compulsory fire test, during which the helmet is subjected to an 800°C flame for 45 seconds. To pass, temperatures inside the helmet are not allowed to exceed 70°C, otherwise it is back to the drawing board. The visor, meanwhile, has its protective qualities evaluated by having projectiles shot at it at 500km/h. The impact marks must not exceed a depth of 2.5mm.
On top of these all-important safety tests, helmets also go through stringent wind-tunnel trials to ensure the design creates minimal drag when the driver is travelling at speed. All in all then, from start to finish developing a Formula One helmet is a long-winded and pricey process. But considering that Massa is already up and about - and talking about getting back behind the wheel - its clearly worth all the effort.