Distributed propulsion system

1. A distributed propulsion system for an aircraft comprising:

a frame;

a plurality of variable displacement hydraulic motors disposed within or attached to the frame in a distributed configuration;

a constant pitch propeller operably connected to each of the variable displacement hydraulic motors;

a source of hydraulic power disposed within or attached to the frame and coupled to each of the plurality of variable displacement hydraulic motors disposed within or attached to the frame, wherein the source of hydraulic power provides sufficient energy density for the aircraft to attain and maintain operations of the aircraft;

a plurality of controllers, each controller coupled to the source of the hydraulic power, and to one of the variable displacement hydraulic motors via a mechanical shaft to control a speed and a torque of the variable displacement hydraulic motor by changing a displacement of the variable displacement hydraulic motor; and

one or more processors communicably coupled to each controller that control an operation, the speed and the torque of the plurality of variable displacement hydraulic motors such that a pitch roll and yaw movement of the aircraft is controlled via differential and vectoring thrust without a rotor cyclic and collective controls.

2. The system of claim 1 , wherein the variable displacement hydraulic motors are selected based on at least one of aerodynamics, propulsive efficiency, structural efficiency, aeroelasticity, or weight of the aircraft.

3. The system of claim 1 , wherein the aircraft further comprises one or more control surfaces on or about the aircraft.

4. The system of claim 1 , wherein the aircraft is manned or unmanned.

5. The system of claim 1 , wherein the aircraft is a helicopter or a vertical take off and landing aircraft.

6. The system of claim 1 , wherein the source of hydraulic power is one or more batteries, a piston engine, or a turboshaft engine.

7. The system of claim 1 , wherein the aircraft is a closed wing aircraft.

8. The system of claim 1 , wherein the plurality of variable displacement hydraulic motors comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 hydraulic motors.

9. The system of claim 1 , wherein the constant pitch propeller is at least one of a rear folding, or a forward folding propeller.

10. The system of claim 1 , wherein the variable displacement hydraulic motors are self-cooling.

11. The system of claim 1 , wherein the source of hydraulic power comprises one or more batteries, and a variable displacement hydraulic motor pump or a piezo-hydraulic pump connected between the one or more batteries and the plurality of variable displacement hydraulic motors.

12. The system of claim 1 , wherein the source of hydraulic power comprises a turboshaft engine or an internal combustion engine, and a variable displacement hydraulic pump, or generator is connected between the turboshaft engine or the internal combustion engine and the plurality of variable displacement hydraulic motors.

13. The system of claim 1 , wherein the source of hydraulic power comprises a battery that is connected to the plurality of variable displacement hydraulic motors.

14. A method for distributed propulsion of an aircraft comprising:

determining at least one of aerodynamics, propulsive efficiency, structural efficiency, and weight of the aircraft;

selecting a number, size and type of hydraulic motors necessary to provide distributed propulsion for powered operations of the aircraft; and

selecting a power source having sufficient energy density to power the hydraulic motors connected to constant pitch propellers to operate the aircraft; and

providing a distributed propulsion system comprising:

a frame;

a plurality of variable displacement hydraulic motors disposed within or attached to the frame in a distributed configuration;

a propeller operably connected to each of the variable displacement hydraulic motors;

a source of hydraulic power disposed within or attached to the frame and coupled to each of the plurality of variable displacement hydraulic motors disposed within or attached to the frame, wherein the source of hydraulic power provides sufficient energy density for the aircraft to attain and maintain operations of the aircraft;

a plurality of controllers, each controller coupled to the source of the hydraulic power, and to one of the variable displacement hydraulic motors via a mechanical shaft to control a speed and a torque of the variable displacement hydraulic motor by changing a displacement of the variable displacement hydraulic motor; and

one or more processors communicably coupled to each controller that control an operation, the speed and the torque of the plurality of variable displacement hydraulic motors such that a pitch roll and yaw movement of the aircraft is controlled via differential and vectoring thrust without a rotor cyclic and collective controls.

15. The method of claim 14 , further comprising calculating aerodynamics, propulsive efficiency, structural efficiency, or aeroelasticity, and selecting the number, power output, and type of variable displacement hydraulic motors used for distributed propulsion.

16. The method of claim 14 , wherein the aircraft further comprises one or more control surfaces on or about the aircraft.

17. The method of claim 14 , wherein the aircraft is manned or unmanned.

18. The method of claim 14 , wherein the aircraft is a helicopter or a vertical take off and landing craft.

19. The method of claim 14 , wherein the source of hydraulic power is one or more batteries, a piston engine, or a turboshaft engine.

20. The method of claim 14 , wherein the aircraft is a closed wing aircraft.

21. The method of claim 14 , wherein the plurality of variable displacement hydraulic motors comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 hydraulic motors.

22. The method of claim 14 , wherein the constant pitch propeller is at least one of a rear folding, or a forward folding propeller.

23. The method of claim 14 , wherein the variable displacement hydraulic motors are self-cooling.

24. The method of claim 14 , wherein the source of hydraulic power comprises one or more batteries, and a variable displacement hydraulic motor pump or a piezo-hydraulic pump connected between the one or more batteries and the plurality of variable displacement hydraulic motors.

25. The method of claim 14 , wherein the source of hydraulic power comprises a turboshaft engine or an internal combustion engine, and a variable displacement hydraulic pump, or generator, is connected between the turboshaft engine or the internal combustion engine and the plurality of variable displacement hydraulic motors.

26. The method of claim 14 , wherein the source of hydraulic power comprises a battery that is connected to the plurality of variable displacement hydraulic motors.

27. An aircraft comprising:

an airframe comprising one or more control surfaces;

a plurality of variable displacement hydraulic motors disposed within or attached to the airframe in a distributed configuration;

a constant pitch propeller operably connected to each of the variable displacement hydraulic motors;

a source of hydraulic power disposed within or attached to the frame and coupled to each of the plurality of variable displacement hydraulic motors disposed within or attached to the airframe, wherein the source of hydraulic power provides sufficient energy density for the aircraft to attain and maintain operations of the aircraft;

a plurality of controllers, each controller coupled to the source of the hydraulic power, and to one of the variable displacement hydraulic motors via a mechanical shaft to control a speed and a torque of the electric motor or the variable displacement hydraulic motor by changing a displacement of the variable displacement hydraulic motor; and

one or more processors communicably coupled to each controller that control an operation, speed and the torque of the plurality of variable displacement hydraulic motors to attain and maintain flight such that a direction of the helicopter or aircraft is controlled via differential and vectoring thrust without a rotor cyclic and collective controls.

28. A method for distributed propulsion of an aircraft comprising:

determining at least one of aerodynamics, propulsive efficiency, structural efficiency, and weight of the aircraft;

selecting a number, size and type of variable displacement hydraulic motors necessary to provide distributed propulsion for powered operations of the aircraft;

selecting a power source having sufficient energy density to power the variable displacement hydraulic motors connected to constant pitch propellers to operate the aircraft; and

providing a distributed propulsion system comprising:

an air frame;

a plurality of variable displacement hydraulic motors disposed within or attached to the frame in a distributed configuration;

a constant pitch propeller operably connected to each of the variable displacement hydraulic motors;

a source of hydraulic power disposed within or attached to the frame and coupled to each of the plurality of variable displacement hydraulic motors disposed within or attached to the frame, wherein the source of hydraulic power provides sufficient energy density for the aircraft to attain and maintain operations of the aircraft;

a plurality of controllers, each controller coupled to the source of the hydraulic power, and to one of the variable displacement hydraulic motors via a mechanical shaft to control a speed and a torque of the electric motor or the variable displacement hydraulic motor by changing a displacement of the variable displacement hydraulic motor; and

one or more processors communicably coupled to each controller that control an operation the speed and torque of the plurality of variable displacement hydraulic motors via the controller to attain and maintain flight such that a direction of the helicopter or aircraft is controlled via differential and vectoring thrust without a rotor cyclic and collective controls.