Formula One’s Lifesaving Halo Presents Unique Manufacturing Challenges
In November 2020, French driver Romain Grosjean had a fiery crash that he was fortunate to escape from relatively unscathed. In September 2021, rivals Max Verstappen and Lewis Hamilton collided, and the Dutch driver’s rear wheel skidded across the Briton’s helmet.
If it hadn’t been for the precision engineering, manufacturing and testing of the halo security machine, a wishbone-formed structure that’s fitted to the chassis of open-wheel racing automobiles, these incidents could have been life-changing, if not fatal. The halo brought on controversy with fans. Drivers – together with Grosjean – when it was launched. Fans known as it “ugly” and complained that they couldn’t establish drivers as a result of it obscured their helmets. In a video message from his hospital mattress after his crash, Grosjean retracted his opposition to the halo: “I wasn’t for the halo some years ago, but I think it’s the greatest factor that we dropped at Formula 1. Without it I wouldn’t be ready to speak to you in the present day.”
Halo trio
UK-primarily based SS Tube Technology (SSTT) is one in every of three companies that manufactures the halo head protection machine.
Upon listening to that motorsport’s governing physique the FIA intended to introduce halos onto open-cockpit cars in 2017, Nick Henry, engineering director at SSTT, emailed Charlie Whiting, then FIA director and security delegate, and introduced himself and what his company could do.
“He replied much quicker than I believed,” Henry mentioned. “We managed to get a gathering with him and Andy Mellor, who was heading up the venture on the FIA, on the British Grand Prix that yr.”
The FIA was impressed with SSTT’s capabilities and in August 2017 approved SSTT, Germany’s CP Autosport and Italy’s V System to supply halos for F1, Formula 2 and Formula E for the start of their next championships in March 2018.
The FIA stipulates the design of the halo, from the supplies it’s made from (titanium alloy Ti6Al4V grade 5) to the overall weight of the gadget (13.5kg ±0.1kg), in addition to set dimensions and tolerances. “The halo is made up of 4 key elements,” Henry defined. “There’s the central pylon, which is the part that mounts to the monocoque ahead of the driver, then the V-transition that connects the central pylon to the main hoop. Then two billets are gun drilled and machined into tubes, which are every bent to 90° and welded together to create the 180° important hoop.”
The reason for machining a billet, fairly than simply sourcing pre-made tubing, is that grade 5 titanium drawn tube is difficult to make and source within the lead times required. Also, the FIA’s dimensional tolerances are exacting, and unlikely to have been met with drawn tube. Machining allowed SSTT to have higher control of the halo’s dimensions.
Where the halo mounts to the chassis behind the driver’s head and in front of the steering wheel, there are fittings which can be additionally machined from grade 5 titanium sheet and welded onto the halo and bolted and doweled into the chassis by the teams.
Henry added: “The tolerances were extremely tight between the mounting factors, ±0.1mm, there was also a weight tolerance that was important and, clearly, tolerances on the inside/outdoors diameter of the tubes. That was quite a problem. It took a closing machining step to hit these tolerances.”
Tricky to bend
Other than the tolerances, Henry mentioned that the timeframes and the tube bending have been additionally difficult, because grade 5 titanium has high strength, low ductility and exhibits spring again.
“It needs to be bent very slowly, as there’s a strain charge factor to bend it successfully,” he continued. “Also, the V-transition is sophisticated to machine. It’s an expensive lump of titanium to begin with so that you don’t need to get it unsuitable. It takes 30 to 40 hours of machining for each part.”
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