Lines of Defence

Main Image
The ‘Halo’ solution has been designed by Mercedes in conjunction with the FIA
The ‘Halo’ solution has been designed by Mercedes in conjunction with the FIA
The Centre-Line Roll Hoop extends over a driver’s helmet
The Centre-Line Roll Hoop extends over a driver’s helmet
The AFP is designed to lift a tyre over a driver’s helmet
The AFP is designed to lift a tyre over a driver’s helmet

The FIA has been testing a number of potential solutions to help protect drivers from external objects in Formula One and other open-cockpit championships

This is a driver’s-eye view of a Formula One wheel assembly hurtling towards him at 225 km/h. At a distance of 20 metres it would hit that driver’s helmet in under 0.3 seconds and the outcome would be catastrophic.

Fortunately, this ‘driver’ is an empty helmet on the track surface of an airfield in South-East England. And the wheel is being fired from a two-metre long pneumatic cannon under strict test conditions.

More importantly, this particular wheel is being deflected over the helmet by a structure that would sit on the front of the monocoque of an open-wheel racing car. The wheel is scraping along a set of intentionally-curved fins that lead the object up and over the driver’s helmet.

It is all part of an ongoing pursuit by the FIA and its partners to improve safety for drivers in open-wheel racing cars, particularly from external objects. This project started four years ago but has recently taken on extra momentum following a number of injuries and fatalities in the sport.

“We have tried to accelerate this project in the last 12 months with an aim to have something that we can practically apply on the F1 cars for 2017,” says FIA safety director Laurent Mekies. “This latest test was set up with that in mind - trying to come out from there with something that we could actually say, ‘that’s going to be a significant step forward.’”

The tests, which were run by the Global Institute for Motor Sport Safety, the research partner of the FIA Institute, funded by the FIA Foundation, evaluated three potential solutions: a triple-fin on the front of the car; a centre-line roll hoop with three bars that go over the driver; and a halo structure, designed by Mercedes in conjunction with the FIA.

Additional Frontal Protection

The additional frontal protection (AFP) involves putting a structure towards the front of the car, specifically to protect against objects in the path of the car travelling at high speed.

The first AFP solution consisted of three curved fins on the front surface of the chassis. They fan out, when viewed from above, so from the driver’s point of view they appear as three vertical pillars in the lower part of their vision. This kind of solution aims to provide protection during the type of accident suffered by Henry Surtees in Formula Two in 2009, when a detached wheel bounced across the race track into the path of his car, with fatal consequences. “This first test aims to determine how the rim and tyre respond to the new lower-profile fins,” explains Andy Mellor, the lead researcher for the Global Institute on this project. “With this relatively inconspicuous structure we were attempting to impart enough vertical velocity to direct the wheel assembly over the driver’s helmet.”

This solution was designed specifically to put a very controlled load into the wheel when it impacts the structure just above the nose of the car. It is designed to engage with the wheel at the earliest possible time, to maximise the time duration for imparting the vertical velocity, hence minimising the forces.

The front edge of the structure is located close to where the nosecone attaches to the front of the chassis. The curvature of the ramp is designed to generate a constant vertical force of around 40 kiloNewtons to deflect the wheel over the driver’s helmet.

“With this approach we aim to achieve compatibility with the rim with a design that minimises the reaction loads on the chassis, has the potential to be extremely lightweight and has a low visual impact,” says Mellor. “It is designed to work most effectively if the wheel is impacting at a shallow angle but the tests show that even if the wheel impacts the car towards the top of the blades, it can still be deflected over the driver’s helmet.”

Centre-line Roll Hoop

The second concept for testing was the centre-line roll hoop, which aims to offer more complete protection for the driver. It consists of three curved round-section bars that pass above the driver’s helmet, from the main hoop behind the seat to the front of the chassis close to where the nose attaches. Each bar is designed to deflect significantly over its entire length, and generate a constant vertical force of 20 kN, (thus 60 kN in total if the wheel engaged with all three bars), to deflect the wheel over the driver’s helmet.

During the test the bars work exactly as designed, flexing and redirecting the wheel over the driver. “The big difference here is that the structure extends over the driver’s helmet to cover off additional impact positions. This system would also provide protection during the type of fatal accident suffered by Justin Wilson in IndyCar last year,” explains Mellor. For this initial prototype, the bars were made from 20mm diameter steel, but they would be constructed from lightweight composite materials if this concept was taken forward. “The optimum construction would, likely, be a similar-diameter bundle of uni-directional composite fibres fixed in an expoxy matrix.

This structure would be extremely rigid under normal race conditions, but would behave like a cable-car cable during an accident, thus providing a ramp to redirect the wheel over the driver,” Mellor says.

The actual materials could be similar to the very high performance fibres used in Formula One wheel tethers. “During the test the design worked perfectly and the loads measured by the in-wheel data logger were close to those calculated, ensuring there was no fracture damage to the rim,” says Mellor.

However, while working well for driver protection, this solution has other potential complications; firstly it places the three bars in the driver’s forward vision and secondly, it may need to be removable to ensure rapid access during an emergency extrication.

Halo effect

The Mercedes F1 team has been working on a solution that could work from a both safety and chassis-integration point of view. The design integrates the sloping profile of a centre-line fin with a protective roll bar positioned like a halo in front of the driver.

During the tests, this solution performed extremely well and prevented the wheel assembly from impacting the helmet.

“It’s very impressive that although the structure is positioned close to the driver’s helmet to provide protection from all angles, it is still able to prevent the wheel from contacting the helmet,” says Mellor. “In the very short distance available, a huge amount of energy is absorbed and the wheel is successfully redirected.”

A number of tests were performed on this solution from different angles and heights and it performed well each time. The structure was extremely strong and forced the energy management into the impacting wheel and tyre, deforming the rim in all tests.

This prototype version was made out of steel, but if taken forward it would be optimised using lightweight materials, perhaps adding around 5kg to the weight of the car.

Formula Factors

With all three solutions working well, other factors come into consideration, such as driver vision, egress and emergency extrication in the event of an accident. Driver vision is, of course, critical as it is essential that any solution does not introduce an increased risk of accidents occurring. To this end, the FIA has already performed a number of tests to assess the impact of forward structures on a driver’s vision. In August 2013, a forward roll-hoop was fitted to a GP2 Dallara car at Magny-Cours with then-champion Davide Valsecchi at the wheel.

The plan was to gain feedback on the viability of placing such a structure in front of the driver’s line of sight.

“We need to avoid creating any blind spots as that would introduce an unacceptable additional risk during racing,” explains Mellor. “We’re looking to achieve a structure that provides a full panorama of forward and sideways binocular-vision, allowing only very small areas of monocular-vision restricted by the structure.”

This concept had already been evaluated in simulators at McLaren and Red Bull Racing, and was complemented by the testing in the GP2 machinery. Valsecchi completed four laps of the circuit with two types of roll-hoop and gave his feedback, which was positive as he did not feel overly hindered during the test. This encouraged the researchers to further pursue the roll-hoop solutions.

For the three solutions in the recent tests, all would pass the driver-vision exam, albeit with some refinement. In particular, the Halo works well because the only structure in a driver’s line of sight is the central part and they are accustomed to structures on the centre-line of the car such as fins and sensor tubes.

The halo part of the structure is above their normal forward vision. Another key consideration is egress, or how easy it is for the driver to get out of the car. Again, all of the potential solutions could be configured to ensure appropriate access. The final key consideration is emergency extrication, where the rescue team would be removing a driver from the car. Again, Mellor believes that by working closely with the drivers, teams and medical and rescue experts, appropriate procedures will be put in place.

Safety Step

Following the tests, the results were presented by F1 Race Director Charlie Whiting to the drivers and the teams’ technical heads. The concepts were received in a positive manner and research will continue to develop the final prototypes, with a view to potential implementation in the 2017 season.

“The good news is that the three structures we tested performed as expected or even better than expected,” says Mekies. “On top of that we have received great guidance from Charlie from the beginning of the project, and a lot of support from the teams who provided us with all their calculations and design power, which has made this step forward possible.”

The Halo solution has been particularly well-received and is one of the options that has been taken forward. But there is still some work to do. The next step will involve mock-ups of some solutions being placed on current F1 cars during practice sessions to assess their practical viability.

“We are pushing very hard to integrate it as early as possible,” says Mekies. “I’m sure it will trigger a few connected research topics, to assess visibility, extrication and some of the other aspects, so I’m expecting some validation testing to be done in the course of the next six months. But we’re all trying to make that cut.”

In theory, from a regulatory perspective, rules need to be set before 1 March for the following season. But they could still be changed following unanimous approval from the teams or on safety grounds by the FIA.

“The real deadline is the teams’ timing to modify their cars accordingly and our capability to assess all the connected issues,” adds Mekies. “Design is done very much in advance in F1, therefore if we want to make 2017 it needs to be decided in the next few months. Nobody wants to rush these things but we are all trying to go as fast as possible.”

This article was originally published in the 14th edition of Auto magazine.