1. Test Process: To evaluate the effect of ice particles on hot-wire probe measurements, the test article was subjected to a range of conditions including super-cooled water (100% liquid), a mixture of ice particles and liquid, and all ice particles (100% ice). Water content measurements and close-up video of the probe sensing elements were acquired for each of these test conditions which are listed in TableI. The super-cooled water conditions were included to allow comparison of hot-wire water content measurements with icing blade measurements. This provided a "baseline" measurement of probe performance relative to a reference measurement. Unfortunately, no such reference was available for the ice phase conditions.
2. Icing ConditionVariability When we were planning this test, we felt it was important to have an independent measurement that could provide us with an estimate of variability in the icing tunnel conditions. This was based on our previous experience in the mixed phase icing tests in 2002, where we observed the ice shaver conditions to have more variability than the super-cooled liquid spray conditions. Thus if we were attempting to identify significant changes in sensor output as a function of different ice shaver conditions, we would need to accountfor thevariability inherent in each condition.