Experimental aerodynamics of a two-dimensional sail

Abstract

Some basic low-speed aerodynamic characteristics of a two-dimensional sail located between endplates were obtained during these investigations for two sail sizes. The effects of the amount of camber (resulting from variation of the slack in the sail) upon the lift, drag, and pitching moment of a sail constituted the major portion of these investigations. A limited study on the advantages of a sail with a jib was made for one particular jib location and camber. Ideally, the results should be independent of sail size. The results of these investigations, although not quite identical, are consistent for the two sail sizes. As the camber (measured in percent of length of the sail perpendicular to the leading edge) increased from zero to 10%, the maximum lift increased from 0.92 to a maximum of 1.7 and remained fairly constant as the camber increased to 23%, then it decreased to 1.5 as the camber further increased to 27%. The maximum ratio of lift to drag at maximum lift occurred at 7% camber. The addition of the jib did not affect the maximum lift relationship with the camber, but it did increase the lift to drag ratio at maximum lift.