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.'
ANN's Daily Aero-Term (11.29.25): Waypoint
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