Recent safety findings have identified ice-contaminated tailplane stall as the cause of a significant number of aviation accidents that have occurred over the past three decades. The NASA Glenn Research Center, the Federal Aviation Administration, industry, and academia have collaborated in research efforts to better understand the ice-contaminated tail-plane stall phenomena and to improve test techniques and design tools to reduce this hazard. An initial research effort, called the NASA/FAA Tailplane Icing Program (TIP), focused on a commuter air-craft configuration. A follow-on program was developed (TIP 2) to examine the tailplane icing effects on a modern business jet configuration with the goals of developing improved test techniques and data bases for similitude and code validation.
To attain these goals, full-scale and subscale tests were required. Glenn's Icing Branch collaborated with the Wichita State University and Learjet, Inc., to conduct icing aeroperformance effect research on three models of a business jet, including a full-scale business jet empennage. The full-scale business jet empennage was tested in NASA Ames Research Center's 40- by 80-ft wind tunnel to obtain aeroperformance data for the clean (no-ice baseline) and ice-contaminated tail. The ice contamination consisted of nine variations of artificial ice shapes that included several LEWICE ice shapes, spoilers, sandpaper roughness, and a casting developed in an Icing Research Tunnel test. Force and moment measurements were made over a range of Reynolds numbers, angle of attack, sideslip, and elevator positions for each ice contamination. Likewise, surface pressure and boundary layer measurements, and some flow visualization were accomplished to aid in code development.
The full-scale data base is being analyzed and will be reported in fiscal year 2001 with comparisons to results from a previous test of a 25-percent-scale business jet empennage model. Also, a 15-percent-scale model of a complete business jet aircraft will be tested with ice on the horizontal tail. This research will provide improved test methodologies for aerodynamically scaling ice contamination and will provide the data bases to serve as valuable resources for designers and code developers as they validate tools for predicting aeroperformance effects with ice contamination. These tools will be highly beneficial to airframe manufacturers by reducing the time and cost of certification for icing conditions.
Full-scale business jet empennage model inside NASA Ames's 40- by 80-ft wind tunnel.
Simulated ice shape on the leading edge of the business jet's horizontal tail.
NASA Glenn icing researcher inspecting an ice casting mounted to the business jet's horizontal tail.
Find out more about icing research at Glenn.
Glenn contacts:Last updated June 14, 2001, by Nancy.L.Obryan@nasa.gov
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