METHOD DETERMINING HYSTERESIS OF STATIONARY AERODYNAMIC FORCES AND MOMENTS Russian patent published in 1998 - IPC

FIELD: experimental aerodynamics of aircraft. SUBSTANCE: method determining hysteresis of stationary aerodynamic forces and moments makes it possible to determine upper and lower boundaries of area of hysteresis measuring these forces and moments while conducting tunnel tests with increase and then with decrease of parameters of experiment of angles of attack and sideslip. It also allows aerodynamic forces and moments corresponding to new dependences arranged inside area of hysteresis to be studied. With this in mind special values of varied parameter of experiment at which sudden change of aerodynamic forces and moments happens are determined after taking measurements. Then measurements of aerodynamic forces and moments are repeated with increase and decrease of value of varied parameter. In this case initial values of parameter before its decrease are selected in each of intervals into which chosen range of change of parameter is divided by special values characteristic of results of measurements with increase of varied parameter. Initial values of parameter with its successive increase are chosen before measurements in each of intervals into which chosen range of parameter is divided by its special values characteristic of measurement results with decrease of parameter. Final values of varied parameter are determined with its decrease by lower boundary of area of hysteresis and final values of varied parameter are determined with its increase by upper value of area of hysteresis. EFFECT: increased accuracy of measurement of hysteresis of aerodynamic forces and moments. 3 dwg