A nonlinear wind-tunnel and computational-fluid-dynamics-based model of the longitudinal and lateraldirectional dynamics for an airbreathing generic hypersonic vehicle is developed. The equations of motion for the generic hypersonic vehicle are derived using Newton's and Euler's equations. Results from wind-tunnel investigations, computational fluid dynamics code simulations, and analytical techniques are used to develop a merged aerodynamic database. Nonlinear analytical optimization techniques are employed to generate analytical expressions for the aerodynamic coefficients. The coupling between the aerodynamics and the propulsion systems is included. As an example, the generic hypersonic vehicle dynamic model is linearized and its behavior is studied at 5 times the speed of sound.
Nomenclature= zero-lift drag increment coefficient C L = total lift coefficient for the basic vehicle C L clean = lift coefficient for the clean or basic aircraft configuration C La = lift increment coefficient for the right elevon C Le = lift increment coefficient for the left elevon C l = total rolling moment coefficient C l = rolling moment with sideslip derivative for the basic vehicle C n = total yawning moment coefficient C np = yawing moment roll-rate dynamic derivative C Y = total side force c = longitudinal reference length, mean aerodynamic chord, ft I = identity matrix I XX , I YY , I ZZ = roll, pitch, and yaw moments of inertia, slug ft 2 M = Mach number P = roll rate Q = pitch rate fQ BE g = body-frame rotational tensor with respect to the Earth frame q = dynamic pressure fqg = body-axis frame rotational quaternion tensor with respect to the Earth frame R = yaw rate R 2 = coefficient of determination S = stream thrust function S ref = reference theoretical wing area, ft 2 T = engine net thrust, lbf V T = vehicle freestream velocity, ft/s W con = weight of fuel consumed W T = weight of the vehicle, lb X, Y, Z = total aerodynamic forces (in body x, y, and z coordinates) X c:g: = longitudinal distance from momentum reference to vehicle center of gravity = angle of attack, deg = sideslip angle, rad = ratio of specific heats = fuselage cone half-angle = Euler pitch attitude angle, deg = pressure drag = Euler bank angle, deg = Euler heading angle, deg