Sensing aircraft icing effects by unsteady flap hinge-moment measurement

Ice-induced flow separation can lead to severe performance degradation and reduced aircraft control effectiveness. In an effort to identify an easily measurable quantity lying at the source of the ice-induced unsteady separated flowfield, the rms flap hinge-moment coefficient was examined. Experimental results show that the time-dependent hinge-moment coefficient indicated unsteadiness in the flowfield while the airfoil lift coefficient was still in the linear range.