Single blade propeller with variable pitch

Patent metadata

Field	Value
Publication number	US-9889925-B2
Application number	US-201414493274-A
Country	US
Kind code	B2
Filing date	Sep 22, 2014
Priority date	Sep 22, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

An improved performance propeller employs a single propeller blade having an axis of rotation and a centripetal force about the axis. A pitch control unit is mounted opposite the single propeller blade and has a compensating centripetal force with respect to the single propeller blade about the axis.

First claim

What is claimed is:

1. An improved performance propeller comprising:
a single propeller blade having an axis of rotation and a centripetal force about said axis;
at least one retention device radially restraining the single propeller blade;
a pitch control unit having a gear box and pitch motor operably connected to the gearbox mounted opposite the single propeller blade, the pitch control unit positioned to provide a balancing force for the propeller about said axis and, said gear box and pitch motor controlably rotating the single propeller blade about the axis of rotation to a target pitch responsive to a control signal.

2. The improved performance propeller as defined in claim 1 wherein the gear box is connected to a hub tube of the single propeller blade, said gear box rotating said hub tube about the blade axis.

3. The improved performance propeller as defined in claim 2 further comprising: at least one bearing engaging the hub tube to support rotation of the hub tube.

4. The improved performance propeller as defined in claim 3 wherein the hub tube extends substantially perpendicularly through a propeller shaft and further comprising a drive motor connected to rotationally power said propeller shaft and,
said at least one bearing comprises a pair of bearings diametrically opposed across the axis of rotation supporting said hub tube in said propeller shaft; and,
said at least one retention device comprises a first lock ring engaging the hub tube adjacent a first one of the pair of bearings and a second lock ring engaging the hub tube adjacent a second one of the pair of bearings.

5. The improved performance propeller as defined in claim 4 further comprising a coupler adapted to engage one of said lock rings to a rotary actuator shaft extending from the gear box.

6. The improved performance propeller as defined in claim 2 wherein the blade axis has a rake angle with respect to the rotational axis.

7. An improved performance propeller comprising:
a single propeller blade having an axis of rotation and a centripetal force about said axis;
a pitch control unit mounted opposite the single propeller blade and having compensating centripetal force with respect to the single propeller blade about said axis, said pitch control unit having a gear box connected to a hub tube of the single propeller blade, said gear box rotating said hub tube about a blade axis to define pitch of the single propeller blade; and, a pitch motor responsive to a control signal operably connected to the gear box wherein at least one of said gear box and pitch motor are offset from the axis.

8. The improved performance propeller as defined in claim 3 wherein the hub tube extends through a cross-member supported by a yoke, said cross member rotatable within the yoke allowing said single propeller blade and pitch control unit to teeter about a teeter axis.

9. The improved performance propeller as defined in claim 8 wherein the teeter axis is angled with respect to the rotational axis.

10. The improved performance propeller as defined in claim 2 further comprising a controller operably connected to the pitch motor and an electrical power source and receiving instructions for blade pitch, said controller providing electrical power to said pitch motor responsive to said instructions.

11. The improved performance propeller as defined in claim 10 wherein the power source is an airplane power source and commutating slip rings and brushes connect the power source to the controller.

12. The improved performance propeller as defined in claim 10 wherein the power source is a generator, said generator having at least one magnet mounted on a stationary side of an interface between stationary and rotating components and at least one coil mounted adjacent to and rotating with the pitch control unit, said coils connected to the controller to provide electrical power.

13. The improved performance propeller as defined in claim 12 further comprising a battery connected to the coils through the controller, said controller distributing power to the battery.

14. The improved performance propeller as defined in claim 10 further comprising a receiver connected to the controller to receive said instructions.

15. The improved performance propeller as defined in claim 14 further comprising a position sensor in the pitch control unit, said position sensor providing a pitch angle output to the controller.

16. The improved performance propeller as defined in claim 15 further comprising a transmitter connected to the controller and transmitting said pitch angle output.

17. The improved performance propeller as defined in claim 2 further comprising a brake connected to a selected one of the pitch motor and gearbox.

18. A method for counter balancing a single blade propeller for higher efficiency in thrust production over conventional multibladed propellers, said method comprising:
selecting a single propeller blade with radius and chord profile combination providing the same total blade area as a two-blade propeller having a desired thrust;
mounting the propeller blade with a hub shaft supported by bearings to a propeller shaft extending from a motor;
securing the hub shaft with retention devices;
attaching a pitch control unit to the propeller shaft with a support bracket and to the hub shaft extending oppositely from the single propeller blade, said pitch control unit having a pitch control motor to drive a gearbox having a rotary actuator output shaft engaging the hub shaft for pitch control responsive to a control signal; and,
spacing a center of gravity of the pitch control unit relative to an axis of rotation of the propeller to provide a balancing force for the propeller blade.

19. The method as defined in claim 18 further comprising:
attaching a pitch control motor to drive a gearbox having a rotary actuator output shaft engaging the hub shaft for pitch control.

20. The method as defined in claim 19 further comprising:
providing electrical power for the pitch control motor by connecting an airplane power source through a commutator and slip ring arrangement from a stationary side of a nacelle to a rotating side of a propeller hub.

21. The method as defined in claim 20 further comprising:
providing electrical power for the pitch control motor by a generator having at least one magnet on a stationary side and at least one coil on a rotating side.

22. The method as defined in claim 19 further comprising:
providing power with a controller to the pitch control motor and to a chargeable energy storage element.

23. The method as defined in claim 22 further comprising:
monitoring blade pitch with a position sensor; and
transmitting said blade pitch to an airplane controller.

24. The method as defined in claim 18 further comprising:
employing a teetering yoke to attach the pitch control unit and hub shaft to the propeller shaft.

25. The method as defined in claim 18 further comprising:
angularly mounting the propeller blade and pitch control unit to create a blade rake angle.

Assignees

• Boeing Co

Inventors

• Rawdon Blaine K

Classifications

• B64C11/06

  for variable-pitch blades · CPC title

• B64C11/00

  Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft · CPC title

• B64C11/44 Primary

  electric · CPC title