Flexible blade for wind driven machine - has rigid and flexible leading and trailing edge spars with profiled spacers

摘要

The flexible blade or sail has a rigid leading edge spar (1) and a flexible trailing edge spar (5) which support a fabric surface (6). In order to maintain a tension in the fabric the profiled spacers (12) are fitted between the spars (1 and 5). By pivoting the flexible spar (5) at its mounting point and then changing its alignment with respect to the rigid spar (6) the angle of incidence of the leading edge can be changed as well as the magnitude of warp of the surface (6). A sail or blade of this type can be used with a windmill and increases its efficiency. It can also be applied to flapping wing flying machines.