Sikorsky on 25 May reached 181kt (335km/h) with its X2 technology demonstrator. It finished the third of four phases of flight-testing that will see the dual counter-rotating rotor pusher flying at speeds up to or greater than 250kt this summer.
The twelfth flight test marked the first time the company attempted to slow the main rotor - by around 5% - while flying faster to keep the main rotors from approaching supersonic tip speeds.
Phase four will begin within weeks, with faster speeds accompanied by the addition of a de-rotated aero sail fairing for the main mast, further main rotor slowing and active vibration control.
Source: Flight International