A History of Ice Protection System Development at Sikorsky Aircraft

Modern rotorcraft must have the capability to operate in all-weather conditions. Sikorsky Aircraft has conducted icing research and ice protection system development for helicopters over the past 58 years and the pace of that work has accelerated during the past two decades. Sikorsky participated in several helicopter icing flight tests, conducted wind tunnel tests of scale models and full-scale components, tested simulated ice shapes, and developed analytical tools for use in the design, certification, and qualification for flight in icing conditions. Engine inlets, airspeed systems, main rotor droop stops, and windshields are generally protected by thermal anti-icing systems. When rotor ice protection is required, rotors are protected with electrothermal deice systems. The UH-60A BLACK HAWK electrothermal rotor ice protection system, developed in the late 1970s, has been installed in 2400 H-60 helicopters and it remains one of the most effective rotor ice protection systems. This paper traces the history of Sikorsky icing tests, presents information on the development of the BLACK HAWK rotor ice protection system, discusses data acquired during model-scale and full-scale airfoil and rotor icing tests, describes methods used to support ice protection system development and qualification/certification, and includes the status of BLACK HAWK Growth Rotor Blade icing qualification and S-92 icing certification.