Driver safety is a priority in Formula 1. After the crash of Jules Bianchi at the 2014 Japanese Grand Prix, a new safety device called the ‘Halo’ was introduced to improve driver safety. The device was initially met with mixed reviews, but the controversy surrounding it has now subsided.
That’s because the Halo has more than proven its life-saving capabilities over the last few seasons. From Charles Leclerc’s incident at Spa in 2018 to Romain Grosjean’s fiery crash in Bahrain in 2020 and more recently, Guanyu Zhou’s car that flipped upside down at Silverstone in 2021. Thanks to the Halo, many drivers have been able to walk away from serious crashes with only minor injuries.
This article explores the engineering behind this revolutionary safety device, which is designed to withstand 15x the static load of Formula 1 cars and a wheel weighing 20kg (44Ibs), travelling at speeds of up to 225kph.
What is Halo?
The Halo, a titanium three-pronged structure, surrounds the cockpit on a Formula 1 vehicle. It is designed to act as a shield that can absorb or deflect forces from an accident. The FIA (Fédération Internationale de l’Automobile) began investigating different frontal protection devices as early as 2011. The governing bodies explored options like full canopies or rollbar structures.
Three potential designs have emerged as possible solutions:
- The Halo
- The Shield – a windscreen made from Opticor plastic
- The Aeroscreen – a combination of the Halo and the Shield
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The FIA designed a series of rigorous safety tests to determine the effectiveness and durability of these devices. These tests involved the application of significant vertical, horizontal, and frontal loads for five second. Only the Halo device passed these tests.
The FIA conducted investigation into accidents in the past, simulating every scenario with the Halo and evaluating its impact on driver safety. In 19 of the 21 case studies, the Halo could have lessened the severity of injuries to drivers.
What is the Halo Made of?
Halo isn’t made of carbon fibers as many people believe. It is actually made of Grade 5 6AL4V, a titanium alloy that is aerospace-grade. This allows for the tubular titanium structure with three prongs to weigh just 7kg but still be able to withstand two African elephants. [1].
Halo is composed of three major elements:
- Front section at the centre which is called the ‘V transition’
- Two tubes that are welded together
- Rear mounts
How is Halo made?
Due to the non-standard sizes of tubes, manufacturers were forced to start all over again. ‘We have to gun drill the bar and then turn the outer diameter before the tube could be bent,’ highlights Daniel Chilcott, Managing Director of SST Technology. ‘Due to the tolerance required between the rear mounts and the main Halo structure, the Halo is actually made from two tube sections that are welded together, not a single piece bent a full 180 degrees.’
Titanium oxidises when heated and so the tubes are bent using a process known as ‘cold bending’. The bending speed must be slow and constant to ensure that the titanium retains its high performance during the entire bending process.
‘The only reason we are able to do that is because we use a fully electric tube bending machine,’ highlights Chilcott. ‘This applies the same amount of torque throughout the process, achieving a proportional bend, rather than using a hydraulic machine which may not be able to apply a consistent load, leading to breakages.’
Welding the titanium tubes is also a challenge, as the material must be shielded to prevent oxidation which could affect the weld’s integrity. ‘We have developed a bespoke shroud technique that we weld the parts within using a unique gas mix to ensure that the welds don’t oxidise in any way,’ says Chilcott.
The V-transition and rear mounts of the X are milled from titanium billets on 3 and 5 axis milling machine. Due to the complexity and size, the V transition requires a minimum of 40 hours of machining. The tube sections, once cooled and welded, are attached to V transition. Also, the rear mounts and structure are welded.
The final step is machining the assembly to ensure it fits the chassis correctly. ‘The tolerance across the bolt holes in the rear feet is 100 microns which is a challenge on what is ultimately a fabricated structure. We address that by securing the Halo by the ‘nose’ and finish machine the rear mounts and without this final process, the Halo wouldn’t fit to the chassis,’ explains Chilcott
What safety standards does Halo need to meet?
Each Halo design must undergo rigorous safety tests as specified by the FIA regulations to become ‘FIA approved’. The Halo is crash tested at Cranfield Impact Centre, the only facility approved in the world to test Halo.
‘The Halo testing consists of two static tests,’ explains Jim Watson, Engineering Manager at CIC. ‘For the first test, the load comes from above at an angle of 22.5 degrees and that is the more straightforward test to do. It is more difficult to test when the load is coming from the side. Both tests reach 125kN and then the load comes off, so we don’t test the ultimate strength of the part, only to the required load specified in the regulations.’
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Once the test is passed, only the structure’s strength can be relied upon to provide assurance. The Halo is then tested during the homologation process of the chassis. During these tests, the Halo is secured to the chassis and there must be ‘no failure of any part of the survival cell or of any attachment between the structure and the survival cell.’
What is the effect of the Halo on aerodynamics?
‘Aerowise, it’s certainly not penalty free,’ says Peter Prodromou, former Chief Technical Officer of Aerodynamics at McLaren. ‘The challenge in the first instance is to cope with it and minimise the losses and thereafter think about the opportunities because it does open up some avenues that are potentially interesting. There are various implications on how it affects the flow into the engine air intake, into certain cooling ducts that teams have in that area, including ourselves, as well as how it effects cooling onto the rear wing.’
The FIA gave teams a 20mm space of freedom to design aerodynamic fairings. This is in part due to the Halo’s aerodynamic losses, especially around the airbox. The teams wrap the titanium chassis in carbon fiber to give the Halo a similar look as the rest.
Who has been rescued by Halo?
Halo, which was introduced to F1 in 2018 has now become a part of the majority of single-seat motorsport categories such as Formula E, F2, F3, Euroformula Open and Super Formula. The widespread adoption of this revolutionary safety system has prevented many serious injuries and saved lives.
The Halo’s effectiveness has been demonstrated in several accidents. The first notable incident was during the 2018 Belgium Grand Prix when Fernando Alonso’s car launched over Charles Leclerc’s cockpit. Leclerc’s Halo was able to protect him, and subsequent analyses estimated that the Halo could endure a 56kN force. [2]Its ability to resist extreme forces and prevent injury.
A massive accident at the Spa Francorchamps circuit occurred during the opening laps of the 2020 Belgian Grand Prix. Multiple cars were involved. Giovinazzi’s car made contact with the rear of Russell’s car, causing it to go airborne and flip over. The Halo on Russell’s car deflected the impact of Giovinazzi’s car, preventing it from directly hitting Russell’s head.
The remarkable life-saving capabilities of the Halo were prominently demonstrated during Romain Grosjean’s harrowing crash at the 2020 Bahrain Grand Prix. His car exploded into flames as soon as it hit a barrier. Miraculously, the Halo deflected the barrier and created a protective zone around Grosjean’s head, allowing him to escape with relatively minor injuries. This incident served as a definitive testament to the Halo’s ability to safeguard drivers in the most treacherous circumstances.
It was initially thought that the collision between Lewis Hamilton, Max Verstappen and the Halo during the Italian Grand Prix of 2021 was minor. But a closer examination revealed its importance. The incident occurred at Turn 2 in Monza, causing Verstappen’s car to go airborne and land on top of Hamilton’s roll hoop and Halo. The Halo protected Hamilton’s head, preventing serious head injuries as Verstappen’s rear-right wheel rotated across the Halo and Hamilton’s helmet.
The British Grand Prix in 2022 witnessed a series of dramatic incidents, including a red flag-inducing crash in which Zhou Guanyu’s Alfa Romeo collided with a catch fence. Zhou Guanyu escaped injury thanks to Halo but the accident overshadowed an incredibly terrifying crash in the Formula 2 Support Race.
Dennis Hauger was involved in a collision after Williams academy driver Roy Nissany defended his position aggressively. Hauger’s car ramped off a curb and into Nissany’s cockpit, but both drivers emerged unharmed as the Halo prevented a potential decapitation.
The Halo has been an integral part in Formula 1’s driver safety. It is a symbol of a collective commitment towards prioritising the safety of drivers and taking proactive steps to reduce risks in high-speed races. Its innovative design, which combines lightweight titanium and fibre carbon, and the rigorous manufacturing process ensures its reliability. The Halo has raised the bar for motorsport safety, giving drivers greater peace ofmind as they push performance limits.
References
[1] 2018. How to make a F1 Halo [Online]. FIA
[2] 2018. FIA confirms level of impact on Leclerc’s Halo in Spa crash [Online]. Crash.net
The article How Formula 1 Halos work first appeared on Racecar Engineering.
