Tail Icing Effects on the Aerodynamic Performance of a Business Jet Aircraft 2002-01-3007
Experimental studies were conducted to investigate the effect of tailplane icing on the aerodynamic characteristics of 15%-scale business jet aircraft. The simulated ice shapes selected for the experimental investigation included 9-min and 22.5-min smooth and rough LEWICE ice shapes and spoiler ice shapes. The height of the spoilers was sized to match the horns of the LEWICE shapes on the suction side of the horizontal tail. Tests were also conducted to investigate aerodynamic performance degradation due to ice roughness which was simulated with sandpaper.
Six component force and moment measurements, elevator hinge moments, surface pressures, and boundary layer velocity profiles were obtained for a range of test conditions. Test conditions included AOA sweeps for Reynolds number in the range of 0.7 based on tail mean aerodynamic chord and elevator deflections in the range of -15 to +15 degrees.
The experimental results showed substantial degradation in the aerodynamic performance of the horizontal tailplane due to the simulated ice accretions and ice roughness. The reduction in the stall lift coefficient of the iced tail with respect to the clean tail due to the LEWICE and spoiler ice shapes was in the range of 5%-33%. The 22.5-min ice accretion caused greater performance losses compared to the 9-min ice shape tested. Aerodynamic performance degradation with the rough LEWICE ice shapes was greater than that obtained with the corresponding smooth LEWICE ice shapes.
The 40-grit sandpaper roughness resulted in 4% to 9% reduction in the clean tail stall lift coefficient depending on roughness extent.
In general, hinge moment coefficients increased due to the presence of the ice shapes but the maximum and minimum hinge moments remained within the limits defined by the clean tailplane hinge moments.
The ice shapes tested reduced the lift performance of the tailplane with elevator deflection. However, the elevator remained effective, in terms of changing tailplane lift, for all angles of attack and elevator deflections tested.
Flap deflection of 0, 8, 20 and 40 degrees were tested with the clean and iced tail to investigate the effect of wing downwash on the aerodynamic performance of the clean and iced contaminated tailplane. In general, tail stall occurred progressively earlier as the flap deflection was increased from 0 to 40 degrees. Tailplane stall caused a significant reduction in the aircraft pitching moment.