Indian Journal of Science and Technology

Abstract

The loads applied to the structure of a plane are of two types, namely Inertia and aerodynamic. Aerodynamic loads result from the effects of the distribution of compressive forces acting on the exterior surface of the plane parts. These loads cannot be measured directly during the flight; however they are usually determined using numerical methods. In this research, the calculating of aerodynamic loads has been considered in all flight conditions. For this purpose, a training airplane has been chosen as a prototype, and also has been divided into small parts longitudinally. Furthermore, numerical solutions have been obtained under different effective parameters such as Mach numbers, angle of attack and control surfaces diversities as applying aerodynamic loads on the plane. Therefore, the magnitude of aerodynamic load which is applied to each part is found for a specific condition. Using resulted loads obtained from the numerical solutions under different applied parameters for each load, an equation has been derived to determine the applied aerodynamic load for each part through the least squares method. In order to obtain the variable values applied in the respective equation, flight simulation has been carried out for the training aircraft. To ensure the accuracy of simulation, its results have been validated with those of the flight tests. Then, the values of the variables used in the equations of the aerodynamic loads of different plane parts during the loop maneuver were recorded by flight simulation. Eventually, by substituting these values in the equations, the aerodynamic loads on different plane parts during the maneuver have been calculated. Results indicated that the proposed method for determination of the plane aerodynamic loads is appropriate.
Keywords: Aerodynamic Loads, Flight Simulation, Loop Maneuver, Flight Test, Regression Equations