Video-analysis of flight of a model aircraft

In recent years, many research studies have pointed out that modelling environments, based on Information Technology, can supply effective pedagogical strategies dealing with complex real-world systems and everyday problem solutions. At the same time, physics teachers have discovered that video analysis is a relatively inexpensive and 188 worthwhile method of studying «real world» examples of phenomena. This kind of approach is often adopted to analyze sports physics. The study of physics of aircraft flight can be considered a real-world topic belonging to the everyone’s common experience. For this reason, here, we use a video-analysis software in order to measure the main dynamic variables, like speed and pitch, describing the longitudinal behaviour of a radio-controlled model aircraft during the take-off, cruise and landing. These experimental results are compared with the theoretical steady-state configurations obtained by using the phugoid model for longitudinal flight. According to this model, the airplane is considered as a point mass subjected to four forces (weight, lift, propulsive thrust and drag), being the direction of all the forces in the model, except weight, dependent on pitch. The discussion is also carried out by showing the trajectories of the aircraft in the phase space. The most relevant effects on the model aircraft flight caused by actions on the radio-controls are examined and explained in terms of aircraft parameter variation. From a pedagogical point of view, this kind of tool can be used to build up several inquiry-based proposals aimed at making students aware of the reasoning procedures to describe, formalise and explain the behaviour of some real systems as the airplanes.