Kite and classical rig sailing performance comparison on a one design keel boat
Résumé
An implementation of a kite modelling approach into 6 degrees of freedom sailboat dynamic simulator is introduced. This enables an evaluation of kite performance in comparison with classical rig sailing. A zero-mass model was used to model kite forces. Influence of the wind gradient was properly taken into account leading to significant modifications in the calculation of the relative wind. The modelling was performed with experimental aerodynamic characteristics. An optimization was done to determine the best kite flight trajectory in terms of performance. Validation steps of the sail yacht simulator were performed for a classical rig on the example of an 8 m one design yacht. The experimental set-up is described and validation results are discussed. Particularly, a wind mesh was used, based on measurements made at four different locations of the navigation spot. Additionally boat motions were recorded by high resolution GPS and inertial unit systems. Speed polar diagram results, reached by kite propulsion, were predicted versus true wind angle. At last a comparison was made for upwind and downwind legs in sea trials conditions, between simulations with the classical rig and the kite. It is shown that the boat towed by kite would achieve much better sailing performance.