Retractable VTOL rotor systems and methods

1. A hybrid multi-rotor aircraft, comprising:

a plurality of vertical propulsion rotors;

a forward propulsion rotor; and

a rotor compartment for each of the plurality of vertical propulsion rotors, the rotor compartments disposed within a respective body portion of the hybrid multi-rotor aircraft, each rotor compartment configured to stow its respective vertical propulsion rotor;

a deployable rotor-compartment cover for each rotor compartment, the deployable rotor-compartment covers each configured to be moved to an open state to allow the vertical propulsion rotors to be deployed for vertical flight modes and to be moved to a closed state to cover its respective vertical propulsion rotor for forward flight operations;

a motor coupled to at least one of the deployable rotor-compartment covers by a linkage, wherein operation of the motor moves the linkage to open and close the at least one of the deployable rotor-compartment covers; wherein the linkage comprises:

an elongate rod having a proximal and a distal end, the proximal end coupled to a shaft of the motor;

an actuating arm having a base portion coupled to the distal end of the elongate rod and an extension portion coupled to its respective deployable rotor-compartment cover.

2. The hybrid multi-rotor aircraft of claim 1 , wherein actuating the motor to rotate the shaft in a first direction pulls the elongate rod down as the proximal end of elongate rod rotates about the shaft, thereby rotating the actuating arm about an axis pulling the base portion of the actuating arm downward and rotating the extension portion of the actuating arm downward thereby pulling its respective rotor-compartment cover downward into a closed position.

3. The hybrid multi-rotor aircraft of claim 1 , wherein actuating the motor to rotate the shaft in a second direction pushes the elongate rod upward as the proximal end of elongate rod rotates about the shaft, thereby rotating the actuating arm about an axis pushing the base portion of the actuating arm upward and rotating the extension portion of the actuating arm upward thereby its respective the rotor-compartment cover upward into an open position.

4. A hybrid multi-rotor aircraft, comprising;

a plurality of vertical propulsion rotors;

a forward propulsion rotor; and

a rotor compartment for each of the plurality of vertical propulsion rotors, the rotor compartments disposed within a respective body portion of the hybrid multi-rotor aircraft, each rotor compartment configured to stow its respective vertical propulsion rotor;

a deployable rotor-compartment cover for each rotor compartment, the deployable rotor-compartment covers each comprising structure configured to be moved upward from its respective body portion and in an aft direction to an open state to allow the vertical propulsion rotors to be deployed for vertical flight modes and to be moved forward and downward toward its respective body portion to a closed state to cover its respective vertical propulsion rotor for forward flight operations; a linkage, wherein the linkage comprises: an elongate rod having a proximal and a distal end, the proximal end coupled to a shaft of the motor; an actuating arm having a base portion coupled to the distal end of the elongate rod and an extension portion coupled to its respective deployable rotor-compartment cover.

5. The hybrid multi-rotor aircraft of claim 4 , wherein the aircraft is a twin-boom aircraft and each boom comprises a forward and an aft vertical propulsion unit, each vertical propulsion unit comprising a motor within its respective boom and one of the plurality of vertical propulsion rotors coupled to the motor, and wherein the rotor compartments are within a portion of the boom.

6. The hybrid multi-rotor aircraft of claim 5 , wherein when in the closed state the deployable rotor-compartment covers form a surface consistent with the surfaces of their respective booms.

7. The hybrid multi-rotor aircraft of claim 4 , wherein the deployable rotor-compartment covers comprise a unitary structure that is raised to move the deployable rotor-compartment cover to an open state and lowered to move the deployable rotor-compartment cover to a closed state.

8. The hybrid multi-rotor aircraft of claim 4 , wherein when in the closed state the deployable rotor-compartment covers form a surface consistent with the surface of the body portion of the aircraft corresponding to their respective rotor compartment.

9. The hybrid multi-rotor aircraft of claim 4 , further comprising a motor coupled to at least one of the deployable rotor-compartment covers by the linkage, wherein operation of the motor moves the linkage to open and close the at least one of the deployable rotor-compartment cover covers.

10. The hybrid multi-rotor aircraft of claim 4 , further comprising

a plurality of magnets within each of the vertical propulsion rotors;

a plurality of corresponding magnets in each of a plurality of stators;

wherein the plurality of magnets within each of the vertical propulsion rotors and the plurality of corresponding magnets in each of the stators are positioned such that attraction between the plurality of magnets within each of the vertical propulsion rotors and the plurality of corresponding magnets in each of the stators orient the vertical propulsion rotors in a fore-aft orientation for stowage.

11. The hybrid multi-rotor aircraft of claim 4 , wherein the aircraft is a multi-boom aircraft and each boom comprises a vertical propulsion unit, each vertical propulsion unit comprising a motor within the boom and one of the plurality of vertical propulsion rotors coupled to the motor, and wherein the rotor compartments are within a portion of the boom.

12. The hybrid multi-rotor aircraft of claim 4 , further comprising:

a plurality of rotor magnets of a first polarity, each rotor magnet of the plurality of rotor magnets of the first polarity affixed to a respective vertical propulsion rotor of the plurality of vertical propulsion rotors in a position offset in a first direction along a rotor axis from a center of rotation of the rotors;

a plurality of rotor magnets of a second polarity, each rotor magnet of the plurality of rotor magnets of the second polarity affixed to a respective vertical propulsion rotor of the plurality of vertical propulsion rotors in a position offset in a second direction, opposite the first direction, along the rotor axis from the center of rotation of the rotors;

a plurality of stator magnets of the first polarity, each stator magnet of the plurality of stator magnets of the first polarity affixed to a respective stator bracket corresponding to a vertical propulsion rotor of the plurality of vertical propulsion rotors, in a position offset from a center of rotation of its corresponding to a vertical propulsion rotor in a first lateral direction perpendicular to a longitudinal axis of a body portion in which the respective stator bracket is housed; and

a plurality of stator magnets of the second polarity, each stator magnet of the plurality of stator magnets of the second polarity affixed to a respective stator bracket corresponding to a vertical propulsion rotor of the plurality of vertical propulsion rotors, in a position offset from a center of rotation of its corresponding to a vertical propulsion rotor in a second lateral direction opposite the first lateral direction and perpendicular to the longitudinal axis of a body portion in which the respective stator bracket is housed;

wherein the plurality of magnets within each of the vertical propulsion rotors and the plurality of corresponding magnets in each of the stators are positioned such that attraction between corresponding ones of the rotor magnets and the stator magnets orient the vertical propulsion rotors in a fore-aft orientation for stowage.

13. A method for hybrid multi-rotor aircraft operation, comprising:

receiving a signal to operate the hybrid multi-rotor aircraft in a vertical flight mode;

in response to the signal to operate the hybrid multi-rotor aircraft in a vertical flight mode, opening a plurality of deployable rotor-compartment covers to permit operation of a plurality of vertical propulsion rotors, wherein opening a plurality of deployable rotor-compartment covers, comprises moving each of the plurality of deployable rotor-compartment covers upward from its respective body portion and in an aft direction to an open position to allow the vertical propulsion rotors to be deployed for vertical flight modes;

causing rotation of the plurality of vertical propulsion rotors to operate the aircraft in a vertical flight mode;

receiving a signal to operate the hybrid multi-rotor aircraft in a forward flight mode; and

in response to the signal to operate the hybrid multi-rotor aircraft in a forward flight mode, closing the plurality of deployable rotor-compartment covers to enclose the plurality of vertical propulsion rotors within their respective rotor compartments, wherein closing the plurality of deployable rotor-compartment covers comprises moving each of the plurality of deployable rotor-compartment covers from the open position forward and downward toward its respective body portion to a closed position to cover its respective vertical propulsion rotor for forward flight operations; a linkage, wherein the linkage comprises: an elongate rod having a proximal and a distal end, the proximal end coupled to a shaft of the motor; an actuating arm having a base portion coupled to the distal end of the elongate rod and an extension portion coupled to its respective deployable rotor-compartment cover.

14. The method of claim 13 , further comprising orienting the plurality of vertical propulsion rotors in a fore-aft orientation prior to closing the plurality of deployable rotor-compartment covers.

15. The method of claim 14 , wherein orienting the plurality of vertical propulsion rotors in a fore-aft orientation comprises removing rotational power applied to the vertical propulsion rotors such that a plurality of magnets within the vertical propulsion rotors are attracted to a plurality of corresponding magnets in their respective stators to orient the vertical propulsion rotors in the fore-aft orientation.

16. The method of claim 15 , wherein:

the plurality of magnets within the vertical propulsion rotors comprise:

a plurality of rotor magnets of a first polarity, each rotor magnet of the plurality of rotor magnets of the first polarity affixed to a respective vertical propulsion rotor of the plurality of vertical propulsion rotors in a position offset in a first direction along a rotor axis from a center of rotation of the rotors;

a plurality of rotor magnets of a second polarity, each rotor magnet of the plurality of rotor magnets of the second polarity affixed to a respective vertical propulsion rotor of the plurality of vertical propulsion rotors in a position offset in a second direction, opposite the first direction, along the rotor axis from the center of rotation of the rotors;

a plurality of stator magnets of the first polarity, each stator magnet of the plurality of stator magnets of the first polarity affixed to a respective stator bracket corresponding to a vertical propulsion rotor of the plurality of vertical propulsion rotors, in a position offset from a center of rotation of its corresponding to a vertical propulsion rotor in a first lateral direction perpendicular to a longitudinal axis of a body portion in which the respective stator bracket is housed; and

a plurality of stator magnets of the second polarity, each stator magnet of the plurality of stator magnets of the second polarity affixed to a respective stator bracket corresponding to a vertical propulsion rotor of the plurality of vertical propulsion rotors, in a position offset from a center of rotation of its corresponding to a vertical propulsion rotor in a second lateral direction opposite the first lateral direction and perpendicular to the longitudinal axis of a body portion in which the respective stator bracket is housed;

wherein the plurality of magnets within each of the vertical propulsion rotors and the plurality of corresponding magnets in each of the stators are positioned such that attraction between corresponding ones of the rotor magnets and the stator magnets orient the vertical propulsion rotors in a fore-aft orientation for stowage.