High Airspeed Testing of the Sikorsky X2 Technology™ Demonstrator

The Sikorsky X2 Technology™ demonstrator aircraft is nearing completion of its flight test evaluation. The demonstrator is a 6000-lb-class vehicle powered by a single LHTEC T800-LHT-801 engine. It employs a fly by wire control system, counter-rotating four-bladed stiff-inplane main rotors and a six-bladed auxiliary propulsor to achieve cruise speeds in the 250 knot range. The demonstrator is designed to combine helicopter operational strengths such as hover efficiency, low speed maneuverability and autorotation capability with expanded hot day high altitude hover performance, high speed maneuverability and cruise speed capability. To date the fully instrumented aircraft has flown to 250 knots true airspeed and has met its design requirements in the areas of aerodynamic performance, flying qualities, acoustics and vibration. Rotor and control system loads and tip clearance have remained within limits without any requirements for modification. A brief overview of the demonstrator aircraft and a recap of the hover/low speed data presented in a previous paper (Ref. 1) is provided. The high speed forward flight envelope expansion process is described. Results in the areas of flying qualities, vibration, performance, structures and stability of the main rotors and propeller are presented.