INITIAL RESULTS FROM THE JOINT NASA–LEWIS/U.S. ARMY ICING FLIGHT RESEARCH TESTS

The NASA Lewis Research Center and the U.S. Army Aviation Engineering Flight Activity conducted a joint research effort in 1988 to investigate various aspects of in–flight and ground based icing simulation facilities and instrumentation characteristics. The instrumented NASA DH-6 and Army JU-21A aircraft obtained concurrent icing cloud measurements both in the natural environment as well as the artificially formed cloud produced by the Army’s JCH-47C helicopter spray tanker. Similar spray cloud measurements were also made inside the NASA Icing Research Tunnel and with a single nozzle calibration fixture, using the same instrumentation. During these ground based tests, the sensor probes were exchanged between both data acquisition systems for additional comparison. Other data taken in–flight with the NASA DH-6 aircraft included ice formation documentation using stereographic and microphotography techniques, wing drag wake surveys with natural and artificial ice accretions, and turbulence measurements behind the spray tanker. Analysis of the test results provides insight on the capabilities and characteristics of icing simulation facilities in relation to the natural icing environment, and considerations that apply to instrumentation used for comparing and interpreting icing cloud parameters.