In past decades a massive improvement of computational fluid dynamics (CFD) methods and the rapid increase of computational resources made it possible to simulate a lot of phenomena appearing during the flow of fluid around objects. In following paper a reliable method of aerodynamic analysis using both CFD and scaled models in the development process of a Very Light Airplane have been presented. A method of preparing a numerical model of an airplane and the aerodynamic analysis methodology have been shown. A numerical calculations using finite volume method implemented in specialized software were performed. What is more important, to perform the aerodynamic tests in wind tunnels, scaled models of an airplane have been prepared using the modern and fast manufacturing technologies, including 3D printing and CNC machining. The results have been shown in the graphs form of aerodynamic force and moment components as function of angle of attack. During research an influence of structural parts of an airplane on aerodynamic characteristics have been analyzed. The qualitative results of a flow around the aircraft body have been presented in form of parameter distribution maps on the airframe surface have been shown. Visualization of pressure distribution have been extended with path lines visualization of the flow. The research described in the paper is an example of professional and innovative approach to the subject matter.

The paper contains the results of CFD analysis of flow inside the simplified engine nacelle, containing the engine in a pusher configuration. The authors have tested a set of solutions to increase an efficiency of the cooling system of this type of engine. Unfortunately, all the positive effects of the fact, that the aircraft engine appears in the wake of the propeller during taxiing and waiting for takeoff, are nonexistent in this type of configuration. An engine overheating is here a problem, because an airflow has to be pulled through the nacelle to cool down the engine block and radiators of cylinder heads. That design demands to analyze the cover shape of the nacelle, to properly use the main propeller pressure jump on the one hand, and rather adequate and complicated flow inside the nacelle to be modelled on the other. The aircraft CAD geometry has been simplified to allow for simple changes of the nacelle cover shape and easily introducing new inlets and outlets. The results prove, that the proper application of scoops gives even better result, than simply removing the cover and baffles from the engine. The exhaust scoops should be placed near the propeller plane in such pusher configuration, because the engine is not covered by the propeller wake.