The curve kick of a football II: flight through the air

The purpose of this study is to assess the fundamental characteristics that cause a football to spin in a curve ball kick due to impact conditions, and then to examine how the change in spin affects the flight of the ball.

Two experimental trials were carried out to examine the aerodynamic properties of footballs during flight. In the first trial, a football was projected with no spin at varying launch velocities and the trajectory of each flight measured and analysed. A drag coefficient was calculated for each test, based on a trajectory model. The second trial involved a football being fired with the same launch velocity, but varying spin conditions (spin axis horizontal in all cases). Again, the trajectory of each flight was measured and drag and lift coefficients were calculated. This information was used to simulate three typical game situations and the effects of foot impact offset distance and weather conditions were examined.