JUH-1H Ice Phobic Coating Icing Tests

Natural and artificial icing tests were conducted on a JUH-1H helicopter. An ice phobic coating was applied to both the main and tail rotor blades. A total of 4.0 productive hours were flown in the artificial environment, and 9.3 hours in natural icing conditions. Artificial tests were conducted utilizing the Helicopter Icing Spray System (HISS) with ambient temperatures ranging from -6 to -23 deg C, and relative humidities of 60 to 90 percent. Natural icing tests were conducted within the ambient temperature range of -2 to -12.5 deg C, with liquid water contents (LWC) ranging from 0.1 to 0.32 gm/ cu m. The artificial icing tests verified proper operation of the test helicopter ice protection system for use as a safety device in subsequent tests. Natural icing tests were conducted to determine the operational potential of G661 ice phobic compound and to gather data to aid in defining icing phenomenon and ice protection equipment design requirements. Due to insufficient quantitative baseline UH-1H rotor blade icing data, it was not possible to determine if the G661 ice phobic compound affected the operational icing capability of the UH-1H helicopter. Nine minor asymmetric ice sheds were encountered, however, no predetermined limit conditions were reached during testing. Excessive equipment and man-hour requirements degrade the practicality of G661 use. The LWC indicators were not adequate to determine ice accretion level and the Integrating Rate Unit (IRU) did not provide a repeatable cue of impending asymmetric ice shed.