The disqualification of Lewis Hamilton and Charles Leclerc from their respective second and sixth places in the United States Grand Prix has brought the underbody plank into the frontline of F1 news for the first time since Michael Schumacher’s Benetton was excluded from victory at Spa 29 years ago. What is the plank for and why has it suddenly come back into the news after so long? To fully understand that requires the telling of some F1 history.