WORLD'S FASTEST HELICOPTER
THE LONGEST LIST OF THE LONGEST STUFF AT THE LONGEST DOMAIN NAME AT LONG LAST

What is the world's fastest helicopter?

Keep in mind that the maximum speed a rotor helicopter can reach, in theory, before spinning out of control is just over 250 miles per hour.

Now that you know that, at an European air show on August 6, 1986 a Westland Lynx ZB500, that was slightly modified, reached a speed of  249.1 miles per hour or 400.8 km/h, making it the world's fastest helicopter.