sentences:  On 14 July 2011, the X2 completed its final flight and was officially retired after accumulating 22 hours over 23 test flights.With the end of development, the X2 will be followed by its first application, the S-97 Raider high-speed scout and attack helicopter.It was donated to the National Air and Space Museum in October 2016 and is on display in the Steven F. Udvar-Hazy Center in Chantilly, Virginia.