| 摘要 |
A direction indicator 301 comprises a direction pointer 302 arranged to pivot about a fulcrum 303, and a flight 305 mounted on the direction pointer 302 that is capable of interacting with a fluid flow. The flight 305 has a resistive portion resistive to fluid flow in a direction parallel to a longitudinal axis of the direction pointer 302 which is substantially effective to cause the direction pointer 302 to pivot about the fulcrum 303 and thereby align the flight 305 with the direction of the fluid flow. |
