Tandem tip-joined rotor blade and hub coupling for passive pitch angle control

A rotor blade system, comprising:

• a hub for rotational movement in a defined direction of rotation;
• and
• a plurality of rotor blades, each of said rotor blades including
• a first airfoil having a quarter-chord defined along a span of said first airfoil, said first airfoil coupled to said hub but uncoupled from said rotational movement of said hub, said first airfoil having a tip,
• a second airfoil having a quarter-chord, said second airfoil coupled to said hub for rotation in direct correspondence to said rotational movement of said hub, said quarter-chord of said first airfoil leading said quarter-chord of said second airfoil when said hub experiences said rotational movement in said defined direction of rotation, said second airfoil having a tip, and
• a connector for coupling said tip of said first airfoil to said tip of said second airfoil.

A rotor blade system for operation above a ground surface, comprising:

• a hub for rotational movement in a defined direction of rotation and in a plane approximately perpendicular to the ground surface;
• and
• a plurality of rotor blades, each of said rotor blades including
• a first airfoil having a quarter-chord defined along a span of said first airfoil, said first airfoil coupled to said hub but uncoupled from said rotational movement of said hub, said first airfoil having a tip,
• a second airfoil having a quarter-chord, said second airfoil coupled to said hub for rotation in direct correspondence to said rotational movement of said hub, said quarter-chord of said first airfoil leading said quarter-chord of said second airfoil when said hub experiences said rotational movement in said defined direction of rotation, said second airfoil having a tip, and
• a connector for coupling said tip of said first airfoil to said tip of said second airfoil.