Airship aerodynamics - Modeling principle of the aerodynamic forces by PEM method

This article describes a Projection Equivalent Method (PEM) as a new approach for modeling of aircraft. PEM is a method [20] by which it is possible to obtain a mathematical model of the aerodynamic forces and moments acting on the flying machine during flight. For PEM, it is characteristic that in principle it provides an acceptable regression model of aerodynamic forces and moments, which possesses a reasonable and plausible behavior from dynamics viewpoint. The main advantage of the PEM is that it is not necessary to carry out measurements in wind tunnel for identification of model parameters. Plausible dynamic behavior of the model can be achieved by specific correction parameters, which are possible to be determined on the base of experimental data obtained during a flight of the aircraft. In this article, we present the Projective Equivalent Method, which is applied to an airship. The airship is a special flight system, which is extremely sensitive to the aerodynamic forces impact. Therefore an airship is a suitable object for the comparison of a flight mechanics model providing data calculated by PEM and sensor data from experimental flight.