Publisher's Synopsis
The need for fundamental research in Ice Contaminated Tailplane Stall (ICTS) was established through three international conferences sponsored by the FAA. A joint NASA/FAA Tailplane Icing Program was formed in 1994 with the Ohio State University playing a critical role for wind tunnel and analytical research. Two entries of a full-scale 2-dimensional tailplane airfoil model of a DHC-6 Twin Otter were made in The Ohio State University 7x10 ft wind tunnel. This report describes the second test entry that examined additional ice shapes and roughness, as well as airfoil section differences. The addition data obtained in this test fortified the original database of aerodynamic coefficients that permit a detailed analysis of flight test results with an OSU-developed analytical program. The testing encompassed a full range of angles of attack and elevator deflections at flight Reynolds number conditions. Aerodynamic coefficients, C(L), C(M), and C(He), were obtained by integrating static pressure coefficient, C(P), values obtained from surface taps. Comparisons of clean and iced airfoil results show a significant decrease in the tailplane aeroperformance (decreased C(Lmax), decreased stall angle, increased C(He)) for all ice shapes with the grit having the lease affect and the LEWICE shape having the greatest affect. All results were consistent with observed tailplane stall phenomena and constitute an effective set of data for comprehensive analysis of ICTS.Gregorek, Gerald and Dresse, John J. and LaNoe, Karine and Ratvasky, Thomas (Technical Monitor)Glenn Research CenterDE HAVILLAND AIRCRAFT; HORIZONTAL TAIL SURFACES; WIND TUNNEL TESTS; AERODYNAMIC COEFFICIENTS; AIRFOIL PROFILES; AIRCRAFT ICING; AIRCRAFT PERFORMANCE; LOW SPEED WIND TUNNELS; ANGLE OF ATTACK; FLIGHT CONDITIONS; REYNOLDS NUMBER; PRESSURE DISTRIBUTION; SURFACE ROUGHNESS; AIRCRAFT STABILITY; BOUNDARY LAYERS; FULL SCALE TESTS; PITCHING MOMENTS...