Development of Stall Margin Instrumentation Designed for use in Icing Conditions

This paper presents further development of stall margin instrumentation designed for use in icing conditions. Initial work developing this instrumentation was conducted on a NACA 0018 wing model in Western Michigan University's wind tunnel.¹ The results from this work showed promise and work continued on a NACA 23012 wing. The work on the NACA 23012 wing is presented here. The stall margin instrumentation system maintains accuracy independent of wing leading edge ice formations. The stall margin system uses four surface pressures, measured aft of the ice formation, from which the aircraft's normalized lift coefficient is determined. The pressure port locations are selected such that the calibration algorithm remains nearly constant as the leading edge ice shape and thickness change. This allows the normalized lift coefficient to be known for iced and non-iced conditions. Pressure and force data were taken on a 14 inch chord NACA 23012 wing at Reynolds numbers ranging from 700,000 to 1,300,000. Multiple tests were conducted for the non-iced and the four iced configurations. Four pressure ports were found that allowed a non-iced calibration to be accurate with ice on the leading edge of the wing.