This is officially the fastest helicopter in the world: the Westland Lynx. A demonstrator designed by Britain’s Westland Helicopters (now part of the Leonardo Group) in the early 1970s and jointly produced with Aerospatiale. At the controls of his flying machine on 11th August 1986, John Trevor Eggington reached a speed of 249 mph (400 km/h).
Since then, others have flown faster. For example, the X3 high-speed demonstrator from Airbus Helicopters (Eurocopter at the time) attained 293 mph (472 km/h) in 2013.
However, this record has not been approved by the International Aeronautical Federation (FAI) and is likely to be smashed at the end of the year, when Bell Helicopter starts flight tests for its V-280 Valor. According to the American manufacturer, its machine will fly at over 320 mph (520 km/h). Watch this space.