The inverse snlution problem of vehicle motion in maneuvering flight is discussed in which the control inputs can be determined su as to enable a vehicle to perform a specified maneuver. For a nonlinear dynamic system such as a helicopter, imprnviug the mathematical model of helicopter maneuvering flight and the corresponding solution technique is one of the most complex and challenging problems in applied mechanics. In this paper a set of nonlinear equations governing the helicopter in maneuvering flight is developed and solved by using a new iuverse solution technique. The inverse solution technique is improved to emphasize nonlineaedy and good stability and convergence of the sample calculations of level turn, lateral jink, and pup-up maneuvers for twn kinds of helicopters. Beginning with a set of prescribed flight conditions, this inverse solution calculates the flight path, velocity, and other kinematic parameters first, and then the control inputs, flight altitude, and the load factor for the specified maneuver.

The flow fields around NACA0012, NACA23012 and OA207 airfoils can be calculated by solving the Euler Navier Stokes equations. The far-field noise generated by NACA0012 airfoilvortex interaction is predicted using the combined Euler-Kirchhoff method. The Kirchhoff surfice is selected as one of the grid surfaces. Firstly, the result of flow field under airfoil-vortex interaction can be obtained by solving the Euler equations. Then the result of far-field noise can be obtained by the Kirchhoff method. Finally, the combined Euler-Kirchhoff method developed here is proved to be good for studying blade-vortex interaction noise through sample calculations.

The helicopter has evolved into one of the most powerful flight vehicles for air domination at low level. There are many factors that influence the success of a helicopter in manoeuvre gaming. Among those factors, the helicopter must have the manoeuvrability and agility to gain a favourable firing position first, and then the whole system must be able to achieve first round hits for successful manoeuvre gaming. In an attempt to address these factors, a general analytical model of helicopter manoeuvring flight and the projectile path is established in this paper. Taking helicopter manoeuvre gaming (blue helicopter versus red helicopter) at short range as an example, the inverse solution technique can be described with the following three stages. Firstly, this medthod calculates the kinematic parameters of the blue helicopter and then the fight attitudes and control law of the blue helicopter. At the final stage, the red helicopter position, projectile path, hit time and the firing position of the turreted gun are calculated.