An experimental and analytical investigation of isolated rotor flap-lag stability in forward flightFor flap-lag stability of isolated rotors, experimental and analytical investigations are conducted in hover and forward flight on the adequacy of a linear quasi-steady aerodynamics theory with dynamic inflow. Forward flight effects on lag regressing mode are emphasized. Accordingly, a soft inplane hingeless rotor with three blades is tested at advance ratios as high as 0.55 and at shaft angles as high as 20 deg. The 1.62-m model rotor is untrimmed with an essentially unrestricted tilt of the tip path plane. By computerized symbolic manipulation, an analytical model is developed in substall to predict stability margins with mode indentification. It also predicts substall and stall regions to help explain the correlation between theory and data. The correlation shows both the strengths and weaknesses of the data and theory, and promotes further insights into areas in which further study is needed in substall and stall.
Document ID
19870061680
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gaonkar, Gopal H. (Florida Atlantic University Boca Raton, United States)
Mcnulty, Michael J. (U.S. Army, Aeromechanics Laboratory, Moffett Field CA, United States)