31st July 2010. Amazingly the title for the Worlds Fastest Helicopter has stood since the mid-1980s. The previous record of 249 mph was held by a British Army Westland Lynx helicopter. As it stands at the moment, the Sikorsky X2's maximum recorded speed is 258 mph, but it's an unofficial top speed. To claim the official Guinness title they'll need to repeat the high-speed run with Guinness officials and their timing gear present.