Effect of aspect ratio on lift and drag coefficients of cambered plates

This paper describes the effect of aspect ratio on the lift and drag charac teristics of the cambered plates in free stream. Nine types of model plates (camber ratio of 15%) with different aspect ratios (0.5 similar to 6.0) we re tested in a circulating water tank. The lift coefficient took the maximu m value of 1.783 for the model plate with the aspect ratio of 1.0, while th is decreased at the aspect ratios ranging from 1.0 to 3.0, but increased ag ain gradually at aspect ratios over 3.0. However, the lift-to-drag ratio in creased with increasing aspect ratio. These findings were consistent with t he data of the Clark Y type airfoil by Zimmerman. Because maximum lift coef ficient is more important than lift-to-drag ratio for the otter boards, a s tudy for practical utility may be needed for the cambered otter boards with small aspect ratios of approximately 1.0.