Bistable pitch propeller system with unidirectional propeller rotation
A propeller includes a blade free to rotate about a longitudinal axis of the blade. The propeller also includes a mechanical stop positioned to engage mechanically a first portion of the blade and/or a first structure coupled mechanically to the blade when the blade is in a first position. The propeller also includes a magnetic stop positioned to engage magnetically a second portion of the blade and/or a second structure coupled mechanically to the blade when the blade is in a second position. The blade rotates to the first position against the mechanical stop when the propeller is rotated at a first rotational speed and the blade rotates to the second position against the magnetic stop when the propeller is rotated at a second rotational speed in a same direction as when the blade is in the first position.
1. A propeller, comprising:
a blade free to rotate about a longitudinal axis of the blade within at least a defined range of motion;
a mechanical stop positioned to engage mechanically one or both of a first portion of the blade and a first structure coupled mechanically to the blade when the blade is in a first position at a first end of said defined rotational range of motion; and
a magnetic stop positioned to engage magnetically one or both of a second portion of the blade and a second structure coupled mechanically to the blade when the blade is in a second position at a second end of said defined rotational range of motion;
wherein the blade rotates to the first position against the mechanical stop when the propeller is rotated at a first rotational speed and the blade rotates to the second position against the magnetic stop when the propeller is rotated at a second rotational speed in a same direction as when the blade is in the first position.
2. The propeller of claim 1 , wherein the first rotational speed is faster than the second rotational speed.
3. The propeller of claim 1 , wherein the first structure is the same as the second structure.
4. The propeller of claim 1 , wherein the first position is associated with hovering and the second position is associated with forward flight.
5. The propeller of claim 1 , wherein:
the blade is a first blade; and
in the event the first blade rotates from the first position to the second position, the first structure of the first blade is configured to push a second blade into the second position if the second blade is in the first position.