Unique Rotorcraft Development Program Seen As Sikorsky R&D Benchmark

Few (if any) rotorcraft development programs have earned the intense interest and scrutiny devoted to the Sikorsky X2 Coaxial Pusher concept. About as unique as a rotorcraft gets these days, this program has set the heli world on its ear with the promise of a viable helo design that could conceivably be put into service within just a few years and readily stomp through 250 knots, in the process. Yeah, Sikorsky got the rotor community's attention... and in a very big way.

Aiming to achieve the highest speed ever recorded for a helicopter, the X2 Technology demonstrator combines an integrated suite of technologies intended to advance the state-of-the-art, counter-rotating coaxial rotor helicopter. It is designed to demonstrate a helicopter can cruise comfortably at 250 knots while retaining such desirable attributes as excellent low speed handling, efficient hovering, and a seamless and simple transition to high speed.

Sikorsky began to commit resources and full funding for X2 Technology program development in 2005. The Sikorsky X2 technology demonstrator aircraft incorporates several new technologies. These technologies include an integrated Fly-by-Wire system that allows the engine/rotor/propulsor system to operate efficiently, with full control of rotor rpm throughout the flight envelope, high lift-to-drag rigid blades, low drag hub fairings, and Active Vibration Control.

 In addition, the aircraft will be used as a 'flying wind tunnel' to determine the main rotor to propulsor aerodynamic interaction, shaft angle optimization for performance, and blade tip clearance for a range of maneuvers.

Sikorsky notes that, 'Historically, vertical flight has required a compromise between hover performance and forward speed. If you look at efficiency vs. speed image on the right; the desired helicopter attributes (good hover efficiency, low speed controllability, low downwash, hover endurance) fall to the left of the plot.

High disk loading aircraft such as Harriers and JSF, fall on the right of the plot: while fast, their hovering capabilities are limited, and their operational costs tend to increase due to the required power loading. Sikorsky is focused on creating an aircraft that operates to the right on this scale: providing more speed without compromising the essential attributes that make helicopters valuable.'

FMI: www.sikorsky.com, www.aero-tv.net, www.youtube.com/aerotvnetwork, http://twitter.com/AeroNews