Sikorsky developed the X2 helicopter on a $50 million budget. The design includes expertise gathered from several earlier design projects. The S-69/XH-59A Advancing Blade Concept Demonstrator had shown that high speed was possible with a coaxial helicopter with auxiliary propulsion (two jet engines), but that vibration and fuel consumption was excessive;[3][4][5] the Cypher UAV expanded the company's knowledge of the unique aspects of coaxial flight control laws with a fly-by-wire aircraft; and the RAH-66 Comanche developed expertise in composite rotors and advanced transmission design.[6][7] Other features include slowed[8] "de-swirling"[9] rigid rotors two feet apart, active force counter-vibration inspired by the Black Hawk,[10] and using most of the power in forward flight for the pusher propeller rather than the rotor.[3] Test flights and flight simulations were combined to improve test procedure.[11][12] The fly-by-wire system is provided by Honeywell, the rotor by Eagle Aviation Technologies, anti-vibration technology from Moog Inc, and propeller by Aero Composites.[13] The rotor hub can have 10-20 times the drag of the blade.[14] Sikorsky intended to test hub fairings to reduce drag by 40%,[15] and test flew fairings on the hubs themselves but not the central hub fairing ("aero sail") in between the hubs.[16] Sikorsky has since patented a "Standpipe" (fixed tube between rotating rotor axes) suitable for a central hub fairing.[17]

On 4 May 2009, Sikorsky unveiled a mockup of a Light Tactical Helicopter derivative of the X2,[18] and unveiled a prototype in October 2014.[19][20][21]

In June 2014, Sikorsky/Boeing submitted the SB-1 Defiant helicopter design for the Future Vertical Lift program based on the X2 principle,[22][23] which was approved by the Army in October.[24]