Dual-Pitch Support for a Propeller

Abstract

Apparatus are disclosed that are configured to passively rotate a propeller blade from a first pitch angle to a second pitch angle. An example apparatus involves: (a) a rotor hub, (b) at least one dual-pitch support coupled to the rotor hub, wherein the dual-pitch support has a first surface, a second surface and a cavity defined there between, and (c) at least one propeller blade rotatably coupled to the rotor hub such that a blade root is disposed within the dual-pitch support's cavity, where the blade root's front face is positioned against the dual-pitch support's first surface in a first position and the blade root's back face is positioned against the dual-pitch support's second surface in a second position, and the propeller blade is oriented at a first pitch angle in the first position and is oriented at a second pitch angle in the second position.

We claim: 
     
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         10 . An apparatus, comprising:
 a rotor hub;   at least one dual-pitch support coupled to the rotor hub, wherein the at least one dual-pitch support has a first surface, a second surface and a cavity defined between the first surface and the second surface; and   at least one propeller blade rotatably coupled to the rotor hub, wherein the propeller blade includes a blade root and at least one protuberance extending radially from the blade root, wherein the at least one protuberance is arranged within the cavity defined between the first surface and the second surface of the at least one dual-pitch support, wherein the at least one protuberance defines a first shoulder and a second shoulder, wherein the first shoulder of the at least one protuberance is positioned against the first surface of the at least one dual-pitch support in a first position and the second shoulder of the at least one protuberance is positioned against the second surface of the at least one dual-pitch support in a second position, and wherein the at least one propeller blade is oriented at a first pitch angle in the first position and is oriented at a second pitch angle in the second position.   
     
     
         11 . The apparatus of  claim 10 , wherein the at least one protuberance comprises one protuberance. 
     
     
         12 . The apparatus of  claim 10 , wherein the at least one protuberance comprises a first protuberance and a second protuberance, and wherein the first protuberance defines the first shoulder and the second protuberance defines the second shoulder. 
     
     
         13 . The apparatus of  claim 10 , wherein the at least one propeller blade is coupled to the rotor hub via a bearing. 
     
     
         14 . The apparatus of  claim 10 , wherein the propeller blade is coupled to the rotor hub via a ball and socket joint. 
     
     
         15 . The apparatus of  claim 10 , wherein the first shoulder is configured to be removably coupled to the first surface of the dual-pitch support and the second shoulder is configured to be removably coupled to the second surface of the at least one dual-pitch support. 
     
     
         16 . A method, comprising:
 operating a propeller system in a first mode, wherein the propeller system comprises a plurality of propeller blades each oriented at a first pitch angle, wherein a first force acts on the propeller blades as a result of operating in the first mode and maintains the propeller blades at the first pitch angle;   transitioning the propeller system from the first mode to a second mode, wherein a second force acts on the propeller blades as a result of operating in the second mode, wherein at least the second force causes the plurality of propeller blades to rotate to a second pitch angle; and   operating a propeller system in the second mode, wherein the second force maintains the propeller blades at the second pitch angle.   
     
     
         17 . The method  claim 16 , wherein the first mode is a hover mode and the second mode is a forward flight mode. 
     
     
         18 . The method of  claim 16 , wherein the first force results from a first air pressure gradient profile and the second force results from a second air pressure gradient profile. 
     
     
         19 . The method of  claim 16 , further comprising:
 generating a third force via a pulse of torque from a motor of the propeller system, and wherein the third force further causes the plurality of propeller blades to rotate to a second pitch angle.   
     
     
         20 . The method  claim 16 , further comprising:
 transitioning the propeller system from the second mode to the first mode, wherein the first force causes the plurality of propeller blades to rotate to the first pitch angle.