-The direct dynamics study of Gough-Stewart hexapod platforms presented in this paper represents a preparatory step towards the direct dynamics study of a double hexapod, i.e., two Gough-Stewart platforms mounted in parallel one above the other. The direct dynamics model used here is based on the redundant parameterization of rotations by full 3 dynamics of each solid of the hexapod platform comprises 12 scalar differential equations (3 for each translation and 9 for each solid rotation) and 6 algebraic scalar orthogonality equations, plus the algebraic constraints characterizing the joints. For the entire hexapod, the overall differentialalgebraic system comprises 156 scalar differential equations and 78+72=150 scalar algebraic equations. Of course, a number of 150 scalar Lagrange multipliers are introduced in association with fulfilling the algebraic equations. So, our dynamic modelling technique involves an increased number of parameters and equations, but this disadvantage is compensated by the fact that the dynamic equations can be written in a systematic way, being structurally similar for each solid of the hexapod multibody system. From the numerical point of view, the differential-algebraic system is solved by an iterative "shooting method", using classical adaptive step size Runge-Kutta integration. No convergence troubles were encountered so far, when studying the direct dynamics of the Gough-Stewart hexapod platform considered as case study.