The Boeing–Sikorsky RAH-66 Comanche was an advanced five-blade armed reconnaissance and attack helicopter designed for the United States Army. The RAH-66 program was canceled in 2004, before mass production began, after nearly US$7 billion was spent on the program.


During the early 1980s, the U.S. Army began formulating a requirement for the replacement of its helicopters then in service, resulting in the Light Helicopter Experimental program. In 1991, the Boeing–Sikorsky team was chosen to produce prototypes. The Comanche would incorporate stealth technologies, featuring a number of designs previously untried. It was to employ advanced sensors in its reconnaissance role, and was intended to designate targets for the AH-64 Apache. The aircraft was also armed with missiles and rockets to destroy armored vehicles. Two RAH-66 prototypes were built and conducted flight testing from 1996 to 2004. Since the cancellation, the prototypes have been placed on display.