In 2005 Sikorsky began developing the X2 to increase helicopter speeds. The X2 made its first flight in 2008. On September 15, 2010, it achieved a level flight speed of 250 knots (463 kilometers/288 miles per hour)—a 15 percent improvement on the record top speed of a conventional helicopter. As a result, Sikorsky Aircraft and the X2 Technology Demonstrator Team received the Collier Trophy.

On conventional helicopters, “retreating blade stall” causes a loss of lift on one side of the rotor and limits forward speed. The X2 solved this problem with coaxial rotors stacked one above the other. The blades encounter retreating blade stall simultaneously and counteract each other. New technologies, such as active vibration control, fly-by-wire flight controls, rigid rotor blades, low drag hub fairings, and an integrated propeller drive system to prevent excessive vibration and drag, made this solution practical.

Rotor diameters: 8.1 m (26 ft 5 in)
Length: 9.1 m (29 ft 10 in)
Height: 2.4 m (7 ft 10 in)
Weight, empty: 2,404 kg (5,300 lb)
Weight, gross: 2,722 kg (6,000 lb)
Engine: LHTEC T800-LHT-801, 1,563 shp
Crew: 1
Manufacturer: Sikorsky Aircraft

The X2 was recently added to the Museum's collection and can be seen on view at the Steven F. Udvar-Hazy Center in Chantilly, Virginia.