Sikorsky completed the last flight of the X2 demonstrator on 14 July nearly one year after shattering the speed record for helicopters, but the programme was stopped before it could achieve one final goal.
As recently as the Paris Air Show last month, Sikorsky President Jeffrey Pino predicted a central sail fairing would be installed for the final flight. Adding the aerodynamic surface to soften drag induced on mast between the coaxial rotors had been discussed by Sikorsky for nearly a year.
But a picture released by Sikorsky showed that the sail fairing was absent on the X2´s final flight. Sikorsky later explained that the sail fairing was sacrificed to apply more resources to meeting a "fairly aggressive" schedule for flying the first two S-97 prototypes within three years.
"We had planned to install and test the fairing but have since decided our focus needs to shift 100% to the S-97 Raider," Sikorsky said. With the fairing smoothing the airflow between the coaxial rotors, the X2 was expected to achieve even faster speeds. Pino suggested the fairing could increase the speed by "double digits", while another Sikorsky official last September estimated a 15kt speed boost.
The X2 set the speed record without the sail fairing for a helicopter on 15 September last year by reaching 253kt in level flight. The X2 was conceived six years ago under former Sikorsky President Steve Finger in the aftermath of the cancellation of the US Army RAH-66 Comanche, which Sikorsky was developing with Boeing. In May, the X2 industry team was awarded the Collier Trophy by the National Aeronautic Association.
The X2, powered by a coaxial rotor and a pusher propeller, enters retirement after 23 flight tests and 22hr in flight. The $50 million investment by Sikorsky paved the way for launching the S-97 Raider prototype, a high-speed, armed scout expected to achieve first flight in 2014.