Analysis of nonlinear motion for hypersonic non-spinning blunt cones at small angle of attack

With over-lapping sectional fitting technique, the data of wind-tunnel free-flight tests with biplanar optical system at Mach number 6 and small angle of attack, are analyzed. The concrete form of nonlinear aerodynamic derivatives of hypersonic non-spinning blunt cones at small angle of attack is acquired and the characteristic of nonlinear motion of non-spinning cones is studied. The obvious nonlinearity of dynamic stability derivative coefficient has been found at small angle of attack, while the nonlinearity of static stability derivative coefficient is so weak that it can be considered as almost linear. The nonlinear form of aerodynamic derivative coefficients indicate that all the test models appear limit coning motion with different amplitudes between the pitch and yaw direction, except that one model appears limit planar motion. The static stability derivative coefficients are nearly equal in pitch and yaw directions at small angle of attack for each test. All the models, appearing both limit coning motion and limit planar motion, present different dynamic stability derivative coefficients between pitch direction and yaw direction.