title: Experimental determination of baseball spin and lift.
abstract: The aim of this study was to develop a new method for the determination of lift on spinning baseballs. Inertial trajectories of (a) ball surface markers during the first metre of flight and (b) the centre of mass trajectory near home-plate were measured in a pitch using high-speed video. A theoretical model was developed, incorporating aerodynamic Magnus-Robins lift, drag and cross forces, which predicts the centre of mass and marker trajectories. Parameters including initial conditions and aerodynamic coefficients were estimated iteratively by minimizing the error between predicted and measured trajectories. We compare the resulting lift coefficients and spin parameter values with those of previous studies. Lift on four-seam pitches can be as much as three times that of two-seam pitches, although this disparity is reduced for spin parameters greater than 0.4.
authors.affiliation: Department of Mechanical and Aeronautical Engineering, University of California, Davis 95616, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Alaways
authors.forename: M
authors.initials: M
authors.lastname: Hubbard
mesh_terms: D001484:Baseball; D008962:Models, Theoretical; D010825:Physics / Q000706:statistics & numerical data; D012107:Research Design; D019876:Sports Equipment; D013223:Statistics as Topic