Coaxial rotor pair assembly with variable collective pitch rotor / propeller for flight vehicle or drone

A flight vehicle comprising:

• a frame;
• a plurality of rotors mounted to the frame, each of the rotors having a motor associated therewith for driving the respective rotor about a rotor axis that extends in an axial direction and each of rotors comprising a plurality of blades extending in a radial direction;
• at least two of said rotors forming a coaxial rotor pair, each coaxial rotor pair comprising a fixed-pitch rotor and a variable-pitch rotor, the fixed-pitch rotor and the variable-pitch rotor being axially spaced relative to one another on the respective rotor axis and axially aligned along said respective rotor axis for rotation via colinear rotor shafts each extending along the rotor axis;
• the fixed-pitch rotor and the variable-pitch rotor having a first motor and a second motor, respectively, associated therewith for driving the respective rotor about the rotor axis;
• and
• a plurality of speed controllers each associated with and configured to drive each of the first motor and the second motor, said plurality of speed controllers configured to be controlled by a vehicle flight controller;
• wherein the vehicle flight controller is further configured to selectively vary a collective pitch of the plurality of blades of the variable-pitch rotor during rotation of both the fixed-pitch rotor and the variable-pitch rotor about the rotor axis, said plurality of blades of the fixed-pitch rotor being configured to be maintained a constant, fixed pitch during operation of the flight vehicle.