Characterization of water formation mechanisms on hydrophobic radome materials

The degree of hydrophobicity and contact angle of water on different radome coating materials was measured. The ability of these hydrophobic materials to bond to a radome substrate was also observed. The materials tested were; Raydell M-26-OS, Raydell M-15-OS, RA 7947, RA 7943, Teflon/Tedlar and Vellox-140. Each material was bonded to G-10 fiberglass panels and evaluated under conditions simulating dew formation, driving rain, freezing rain. Raydell M-26-OS had a relatively high contact angle, demonstrated excellent boding to a radome material, and had fair hydrophobic properties. RA 7947 and RA 7943 had relatively high contact angles, demonstrated poor and fair bonding, respectively, to a radome material, and exhibited good hydrophobic properties. The Teflon/Tedlar material had a low contact angle, demonstrated good bonding to a radome material, but showed fair to poor hydrophobic properties. The Vellox-140 and Raydell M-15-OS had relatively high to high contact angles, demonstrated excellent and possibly excellent bonding, respectively, to a radome material, and showed good to excellent, respectively, hydrophobic properties. These results were consistent whether the test temperature was 22{degrees}C (72{degrees}F) or -13{degrees}C (8{degrees}F) and whether the water was in the form of a mist or a concentrated stream. Long term tests and the effects of saltmore » spray and dirt and the hydrophobic materials were not examined. 17 refs., 7 figs., 2 tabs.« less