Firing cannons in the quest for F1 cockpit safety

There's something brutally beautiful about the hard, black, defiantly mechanical object pictured on these pages. It has what might be called singularity of purpose. It's a cannon - albeit of a highly specialised kind - whose starkness is writ large against the blue-sky backdrop of this Suffolk airfield.

It was designed, like any of its genre, to fire things at things, but not, in this case, to destructive effect. Rather, it shoots scientifically calibrated objects, within strictly controlled parameters, into other objects, to discover what happens when scripted collisions occur.

Powered by nitrogen gas compressed to 1200psi and fired under only the most exacting circumstances, it has become a vital component in an FIA Institute programme that researches driver-cockpit safety.

And if, one day, exquisitely manufactured and elegantly formed canopies or forward roll hoops are added to F1 cars to better protect the next generation of grand prix drivers, they might have this leviathan to thank.

The cannon is the tool of Andy Mellor, who is head of technical affairs at the FIA Institute. Along with FIA Institute research consultants Peter Wright and Hubert Gramling, he has, for more than a year, been investigating the possible benefits - and drawbacks - of adding additional protection to the open-cockpit area of an F1 car.

The research being carried out by the three was prompted by the F1 Technical Working Group (TWG) - a quorum of senior engineers from a number of F1 teams and bodies directly associated with the sport (such as the FIA Institute) - which concluded that even as driver safety provision continues to improve year on year, the open-cockpit area is one that merits further investigation.

At the 2009 Hungarian Grand Prix, Felipe Massa was seriously injured when he was struck by a spring from Rubens Barrichello's Brawn, and this in particular has raised questions as to whether drivers' heads can be better protected. For 2012, a Zylon strip has been added to all Formula 1 helmets in the visor area, which is where Massa's helmet took the brunt of the impact. But the ongoing research into the use of canopies aims to establish if, and where, further improvements can be made.

Fernando Alonso's near-miss in the Belgian Grand Prix © LAT

The near-miss recorded by Fernando Alonso at this year's Belgian GP, when the flying Lotus of Romain Grosjean crunched his Ferrari at La Source, heightened the urgency surrounding this area of research and prompted McLaren technical director (and F1 TWG member) Paddy Lowe to note: "I think something [ie some form of protection] is inevitable, because it is the one big exposure we've got. You see it time and again, and how many times do you think 'that was lucky'? One day it won't be lucky, and we'll be sitting here saying we should have done something about it..."

Prompted by the TWG's concerns, the FIA Institute has carried out a number of experiments at RAF Bentwaters, a former military airbase near Ipswich.

The first of these tested two types of canopy designed to protect a driver from the impact of a flying object. An experiment was constructed whereby an F1 wheel and tyre, with a combined weight of 20kg, was fired at 140mph, into first, a polycarbonate windshield; and second, a jet-fighter canopy made from aerospace-spec polycarbonate. The results of both impacts were subsequently investigated. The setup of the cannon and, in the first test firing, the windshield, were the result of extensive calculations carried out by Mellor and co. They took as their base point known data from the effect of a bird-strike on a jet-fighter canopy, which assumes a 1.8kg bird impacting at 1000km/h, creates an energy of 73 kilojoules.

Contemporary fighter canopies, such as the one used in this study, are designed to resist this type of impact without discernible damage. The Formula 1 example, however, is rather different.

The flying object under investigation isn't winged and feathery: it's a wheel and tyre with some upright assembly attached and, altogether, it has an assumed overall mass of 20kg. The speed of impact, while still high at 140mph, would be considerably slower than any jet-fighter bird-strike. This mass impacting at this speed creates an energy of 31 kilojoules.

"We reasoned that a bird-strike canopy should be able to cope with a wheel at this speed," said Mellor, "but our objective was to understand the science and engineering of violently deflecting a wheel and tyre from the driver's head area."

The setup of the equipment for these tests required extreme accuracy in order to achieve maximum validity.

Firstly, the cannon: it was supplied by the Bickers Action company - specialists in providing unusual vehicles and equipment for the movie industry, particularly for stunt scenes. It was tweaked for this test by attaching a 1200psi compressed-nitrogen cylinder that would provide the thrust necessary to shoot a piston from its 2.5m barrel.

On firing, a huge compressed nitrogen thrust is built up behind the piston, to allow it to accelerate very rapidly - reaching 140mph in just 2.5 metres, at an average force of 80G.

Over this distance, the piston, still with the wheel-assembly mounted on its tip, is flying - and it's here that some very neat engineering comes into play. In order to replicate the effect of a free-flying wheel assembly hitting a canopy - as it might in a real-life, on-track incident - the wheel must be free of the piston by the time it hits the windshield. It's at this point that a different strand of already-proven F1 safety science is brought into action.

The piston, before insertion into the barrel, is attached to F1-spec wheel tethers that are designed to fail at a force of 80 Kilonewtons. They come into effect at exactly the two-metre mark from the point of exit from the cannon barrel.

"They are designed to quickly take speed out of the piston," says Mellor, "and they're effective at a very precise point, to let the wheel fly freely at the target object." At the very moment the tethers tauten, the tail of the piston passes 20mm-diameter venting holes in the barrel, letting the compressed nitrogen escape, which reduces the thrust behind the barrel. "It's a precisely calibrated setup," explains Mellor. "Quite a lot of engineering has gone into it."

There's more. The wheel assembly at the end of the piston is set at 45° - the angle deemed necessary to let the lower part of the wheel rim (rather than just the rubber tyre surface) come into contact with the target object. The leading edge of both canopy and windshield is 30°, giving a 15° misalignment. Thus, the steeper wheel/tyre hits the shallower windshield and canopy with its lower trailing edge. It can only hold that approach angle thanks to its intricate positioning on the piston end. According to Mellor: "It's a sophisticated interface, designed so that the centre of the barrel drives through the centre of gravity of the wheel."

The result of all the science and engineering up to this point is to allow the 20kg wheel and tyre 500mm of free flight from leaving the piston end as it's slowed by tethers, to impacting the windshield or canopy. "At this speed," notes Mellor, "the wheel is a effectively a wing and wants to take off, so this distance between release and impact has to be kept short."

Three firings are carried out: one onto the windshield and two into the canopy. Firing into the 30mm-thick triple-layer polycarbonate windshield results in it shattering as it deflects the wheel and tyre away from any potential impact with a driver's helmet. The canopy, meanwhile, deflects them without any apparent damage.

Viewing the canopy impact in slow-motion shows it flexing to absorb impact energy, before 'bouncing' the wheel and tyre away.

"It was possible to see that the windshield manages to deflect the wheel over the space that would be occupied by the driver's helmet," Mellor tells us, "but in doing so, it sustained quite a bit of damage. The full canopy deflects it over the top with little - if any - damage visible after the test. There were tyre-transfer marks on both, but on the canopy there was no apparent fracture. It shows it's quite an elastic material that is very efficient at keeping the wheel away."

Both protectors succeeded in keeping a potential impact away from a driver's helmet, but the tests threw up other potential concerns: would driver access and ventilation be restricted? Would visibility be hindered? How heavy would the canopy or shield be? Would they require cleaning (ie a windscreen wiper)?

Some of these concerns have already been addressed by another subject of open-cockpit safety research: the forward-roll-hoop structure.

According to Lowe, this is believed by the TWG to be the most promising avenue of research and may even lead to appropriate safety devices being incorporated into the 2014 technical regulations. "We've looked at the research into some kind of bars that could exist in front of the driver to deflect any incoming wheel or a whole car," he said, speaking after the Belgian GP. "That is not going to cause a closed cockpit, but it would provide some defence against cars sliding along or landing from above."

The structure tested by the FIA Institute looks, at first glance, to be an unremarkable roll hoop, of a kind often seen on any number of racing cars, although it seems distinctly out of place fixed to a metal plate and resting on the concrete at RAF Bentwaters. Its importance, however, lies not in its design, but in how and where it would be mounted on a car. This forward roll hoop has been created with the intention of shielding drivers' heads from debris, and research into where it might most effectively be located is, of course, hugely important.

Manufactured and supplied by the Lotus F1 team, it could, in theory, be fitted to a car from the front edge of the cockpit, opening to the point where the nose section meets the front bulkhead. The hoop's peak height would be 100mm above the top of a driver's helmet, thus forming an impact-deflecting barrier ahead of the driver. It was tested under the same conditions as the canopy and windshield, with promising initial results.

"The roll hoop basically did a very good job," said Mellor, "and was able to keep the wheel away from the driver's head. We tested it both by firing the wheel down the centre of the car, and also by coming at it from an angle."

Another positive outcome of the test was the roll hoop's effect on the impacting wheel/tyre.

One source of concern in research to date has been the deflective effect any open cockpit protection might have: ie if a flying wheel bounced off it, where would it end up? In two separate tests, however, the roll hoop deflated the tyre on impact. "We tend to think that's a good thing," says Mellor. "It means that the wheel doesn't bounce as much. It stops much more quickly if you can deflate the tyre."

Another key area of the process involves striking a balance between head protection and visibility, since forward-mounted structures designed to protect drivers' heads might also dangerously impede sight-lines. During the forward-roll-hoop test, a helmet was placed in the position that a driver's head would occupy relative to the structure.

Mellor emphasises that the range of the research will broaden as it continues, acknowledging that any cockpit protection system will have to be effective in a variety of impacts and scenarios. "The research ultimately can't be restricted only to a wheel strike," he explains, "but it's relevant to use wheels as they have a high mass and are a very real factor in such accidents."

The introduction of open-cockpit protection would, of course, be a huge departure for F1, a sport that has always allowed a view of drivers working the wheel. But in this safety-conscious era, one in which the televised death of a driver in a sporting contest would be deemed entirely unacceptable, pressures to remove known risks are only ever going to increase.

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