Retractable and deployable flight rotor system

1. An apparatus comprising:

a shaft comprising a spiral spline along a length of the shaft;

a rotor comprising a blade extending from the rotor and a tubular hole extending into the rotor, the tubular hole comprising a spiral groove configured to mate with the spiral spline on the shaft, wherein relative rotation between the spiral spline and the spiral groove causes the rotor to linearly move along the shaft; and

a cam surface comprising a recession, wherein the blade nesting in the recession constrains rotation of the rotor about the shaft and allows linear movement of the rotor along the shaft.

2. The apparatus of claim 1 , wherein the blade aligns with an axis of forward flight of an aircraft based on the blade being nested in the recession.

3. The apparatus of claim 1 , wherein the relative rotation between the spiral spline and the spiral groove comprises:

relative rotation in a first rotational direction about the shaft causing the rotor to move along the shaft in a first axial direction, and

relative rotation in a second rotational direction about the shaft causing the rotor to move along the shaft in a second axial direction; and

wherein the first rotational direction and the second rotational direction are opposite one another, and the first axial direction and the second axial direction are opposite one another.

4. The apparatus of claim 3 , further comprising:

a head located at an end of the shaft; and

a spring located between the rotor and the head, the spring configured to stop the linear movement of the rotor along the shaft.

5. The apparatus of claim 4 , wherein:

the rotor is configured to compress the spring based on the rotor moving along the shaft in the first axial direction, and

the spring is configured to apply a force to the rotor in the second axial direction based, at least in part, on the spring being compressed; and

wherein the rotor is configured to move along the shaft in the second axial direction based, at least in part, on the spring applying a force to the rotor in the second axial direction.

6. The apparatus of claim 3 , wherein the spiral groove is configured to drive nesting the blade in the recession based on the relative rotation between the spiral spline and the spiral groove being in the second rotational direction about the shaft; and

wherein the spiral spline is configured to drive withdrawal of the blade from nesting in the recession based on the relative rotation between the spiral spline and the spiral groove being in the first rotational direction about the shaft.

7. The apparatus of claim 1 , further comprising a cam follower positioned about a base of the blade, wherein the cam follower is configured to follow a profile of the cam surface as the rotor rotates about the shaft.

8. An aircraft comprising:

a motor configured to apply torque to a shaft,

the shaft comprising a spiral spline along a length of the shaft;

a rotor comprising a blade extending from the rotor and a tubular hole extending into the rotor, the tubular hole comprising a spiral groove configured to mate with the spiral spline on the shaft, wherein relative rotation between the spiral spline and the spiral groove causes the rotor to linearly move along the shaft; and

a cam surface comprising a recession, wherein the blade nesting in the recession constrains rotation of the rotor about the shaft and allows linear movement of the rotor along the shaft.

9. The aircraft of claim 8 , wherein the blade aligns with an axis of forward flight of the aircraft based on the blade being nested in the recession.

10. The aircraft of claim 8 , wherein the relative rotation between the spiral spline and the spiral groove comprises:

relative rotation in a first rotational direction about the shaft causing the rotor to move along the shaft in a first axial direction, and

relative rotation in a second rotational direction about the shaft causing the rotor to move along the shaft in a second axial direction; and

wherein the first rotational direction and the second rotational direction are opposite one another, and the first axial direction and the second axial direction are opposite one another.

11. The aircraft of claim 8 , wherein the spiral groove is configured to drive nesting the blade in the recession based on the relative rotation between the spiral spline and the spiral groove being in a second rotational direction about the shaft; and

wherein the spiral spline is configured to drive withdrawal of the blade from nesting in the recession based on the relative rotation between the spiral spline and the spiral groove being in a first rotational direction about the shaft.

12. The aircraft of claim 8 , further comprising:

a cavity recessed into a surface of the aircraft, wherein the rotor retracts in the cavity based on the blade being nested in the recession and the rotor deploys from the cavity based on the blade being withdrawn from nested in the recession; and

at least one door configured to, at least in part, cover the cavity while the rotor is retracted in the cavity and to uncover the cavity to allow the rotor to deploy from the cavity.

13. The aircraft of claim 8 , wherein the aircraft comprises an unmanned aerial vehicle.

14. The aircraft of claim 8 , wherein the rotor comprises one selected from the group consisting of a main rotor, a tilt rotor, a tail rotor of the aircraft.

15. A method comprising:

mating a spiral spline on a shaft with a spiral groove in a tubular hole of a rotor, wherein the rotor comprises a blade;

rotating the spiral spline and the spiral groove relative to one another to linearly move the rotor along the shaft; and

stopping rotation of the rotor about the shaft based on the blade nesting in a recession in a cam surface, wherein the blade being nesting in the recession allows linear movement of the rotor along the shaft.

16. The method of claim 15 , wherein the blade being nesting in the recession aligns the blade with an axis of forward flight of an aircraft.

17. The method of claim 15 , further comprising stopping the linear movement of the rotor along the shaft and the relative rotation between the spiral spline and the spiral groove, wherein the stopping causes the rotor and the shaft to synchronously rotate.

18. The method of claim 15 , wherein the relative rotation between the spiral spline and the spiral groove comprises:

relative rotation in a first rotational direction about the shaft causing the rotor to move along the shaft in a first axial direction, and

relative rotation in a second rotational direction about the shaft causing the rotor to move along the shaft in a second axial direction; and

wherein the first rotational direction and the second rotational direction are opposite one another, and the first axial direction and the second axial direction are opposite one another.

19. The method of claim 18 , further comprising:

compressing, by the rotor, a spring based on the rotor moving along the shaft in the first axial direction; and

applying, by the spring, a force to the rotor in the second axial direction based on the spring being compressed, wherein the rotor moves along the shaft in the second axial direction based, at least in part, on the spring applying the force to the rotor in the second axial direction.

20. The method of claim 18 , further comprising:

nesting the blade into the recession based on the relative rotation between the spiral spline and the spiral groove being in the second rotational direction about the shaft; and

withdrawing the blade from the recession based on the relative rotation between the spiral spline and the spiral groove being in the first rotational direction about the shaft.