Solid lubricated blade pitch control system for use within a compressed airstream of a reaction driven rotorcraft
A rotor system is disclosed for a reactive drive rotary wing aircraft. Apparatus and methods are disclosed for maintaining the rigidity of the rotor and eliminating play between flight controls and the rotor by mounting swashplate actuators to a flange rigidly secured to the mast. Methods are disclosed for modulating the temperature of oil pumped over one or more of the mast bearing, swashplate bearing, and spindle bearing. The temperature of air passively or actively drawn through rotor may also be modulated to maintain bearing temperature within a predetermined range. Structures for reducing pressure losses and drag on components due to air flow through the rotor are also disclosed. A rotor facilitating thermal management by oil and air flow is also disclosed. Surfaces interfacing between the swashplate and the mast and between control rods and the swashplate or pitch horn may bear a solid lubricant layer.
1. A rotor system comprising
a mast adapted to mount to an airframe of a rotorcraft;
a shroud surrounding the mast, the mast and shroud defining an air channel;
a hub mounted to the mast and defining a hub cavity in fluid communication with the air channel;
a plurality of blades each defining a blade duct, the plurality of blades being coupled to the hub having the blade ducts thereof in fluid communication with the hub cavity;
a plurality of blade actuators;
a swashplate engaging the mast;
a plurality of actuator rods coupling the plurality of actuators to the swashplate;
a plurality of pitch control rods coupling the swashplate to the plurality of blades; and
a layer of solid lubricant, fused to at least one surface, the at least one surface located at at least one of an interface between the swashplate and the mast, an interface between the swashplate and the plurality of actuator rods, an interface between the swashplate and the plurality of pitch control rods, and an interface between the plurality of pitch control rods and the plurality of blades;
a compressed air source in fluid communication with the air channel;
wherein the swashplate is positioned within the air channel and the plurality of pitch control rods extend from the swashplate into the hub cavity such that the swashplate and pitch control rods are exposed to air flow from the compressed air source through the air channel and hub cavity.
2. The rotor system of claim 1 , wherein:
the interface between the swashplate and the mast comprises a spherical bearing slidably mounted to the mast and defining a spherical surface engaging the swashplate; and
the layer of solid lubricant is fused to at least one of a surface of the mast engaging the spherical bearing, a surface of the spherical bearing engaging the mast, the spherical surface of spherical bearing, and a surface of the swashplate engaging the spherical surface.
3. The rotor system of claim 1 , wherein:
the interface between the swashplate and each of the pitch control rods includes a first aperture defined by the swashplate, a second aperture defined by the pitch control rod, and a pin engaging the first and second apertures; and
the layer of solid lubricant is fused to at least one of the first and second apertures and the pin.
4. The rotor system of claim 1 , wherein:
the interface between the swashplate and each of the plurality of actuator rods includes a first aperture defined by the swashplate, a second aperture defined by the actuator rod, and a pin engaging the first and second apertures; and
the layer of solid lubricant is fused to at least one of the first and second apertures and the pin.
5. The rotor system of claim 1 , wherein:
the interface between a blade of the plurality of blades and a pitch control rod of the plurality of pitch control rods includes a first aperture defined by the blade, a second aperture defined by the pitch control rod, and a pin engaging the first and second apertures; and
the layer of solid lubricant is fused to at least one of the first and second apertures and the pin.
6. The rotor system of claim 5 , wherein the blade includes a pitch control arm and wherein the first aperture is defined by the pitch control arm.
7. The rotor system of claim 1 , wherein the layer of solid lubricant includes at least one of molybdenum disulphide, polytetrafluoroethylene, and boron nitride.
8. The rotor system of claim 1 , wherein the layer of solid lubricant includes at least one of molybdenum disulphide and boron nitride and wherein the layer of solid lubricant is baked onto the at least one surface.
9. The rotor system of claim 1 , further comprising tip jets secured to the plurality of rotor blades in fluid communication with the blade ducts.
10. A method for operating a rotorcraft, the method comprising:
during at least one of taking off, hovering, and landing of the rotorcraft, directing compressed air through an air channel defined by a rotor system, the rotor system comprising
a mast,
a shroud surrounding the mast, the mast and shroud defining the air channel,
a hub mounted to the mast and defining a hub cavity in fluid communication with the air channel,
a plurality of blades each defining a blade duct, the plurality of blades being coupled to the hub having the blade ducts thereof in fluid communication with the hub cavity,
a plurality of blade actuators,
a swashplate engaging the mast,
a plurality of actuator rods coupling the plurality of actuators to the swashplate,
a plurality of pitch control rods coupling the swashplate to the plurality of blades, and
at least one layer of solid lubricant fused to at least one surface, the at least one surface located at least one of at an interface between the swashplate and the mast, an interface between the swashplate and the plurality of actuator rods, an interface between the swashplate and the plurality of pitch control rods, and an interface between the plurality of pitch control rods and the plurality of blades; and
during sustained translational flight ceasing to direct compressed air through the air channel;
wherein the swashplate is positioned within the air channel and the plurality of pitch control rods extend from the swashplate into the hub cavity such that the swashplate and pitch control rods are exposed to the compressed air directed through the air channel.
11. The method of claim 10 , wherein the compressed air has a temperature of about more than 300° F.
12. The method of claim 10 , wherein:
the interface between the swashplate and the mast comprises a spherical bearing slidably mounted to the mast and defining a spherical surface engaging the swashplate; and
the layer of solid lubricant is fused to at least one of a surface of the mast engaging the spherical bearing, a surface of the spherical bearing engaging the mast, the spherical surface of spherical bearing, and a surface of the swashplate engaging the spherical surface.
13. The method of claim 12 , further comprising:
rotating the swashplate about the spherical bearing; and
sliding the swashplate along the mast.
14. The rotor method of claim 10 , wherein the layer of solid lubricant includes at least one of molybdenum disulphide, polytetrafluoroethylene, and boron nitride.
15. The method of claim 10 , wherein:
the layer of solid lubricant includes at least one of molybdenum disulphide and boron nitride; and
the layer of solid lubricant is baked onto the at least one surface.
16. A rotor system comprising
a mast;
a shroud surrounding the mast, the mast and shroud defining an air channel;
a hub mounted to the mast and defining a hub cavity in fluid communication with the air channel;
a plurality of blades each defining a blade duct, the plurality of blades being coupled to the hub having the blade ducts thereof in fluid communication with the hub cavity;
a plurality of blade actuators;
a swashplate encircling the mast;
a plurality of actuator rods coupling the plurality of actuators to the swashplate;
a plurality of pitch control rods coupling the swashplate to the plurality of blades;
a spherical bearing slidably mounted to the mast and defining a spherical surface engaging the swashplate; and
a layer of solid lubricant, fused to at least one of a surface of the mast engaging the spherical bearing, a surface of the spherical bearing engaging the mast, the spherical surface of spherical bearing, and a surface of the swashplate engaging the spherical surface;
a compressed air source in fluid communication with the air channel;
wherein the swashplate is positioned within the air channel and the plurality of pitch control rods extend from the swashplate into the hub cavity such that the swashplate and pitch control rods are exposed to air flow from the compressed air source through the air channel and hub cavity.
17. The rotor system of claim 16 , wherein the layer of solid lubricant includes at least one of molybdenum disulphide, polytetrafluoroethylene, and boron nitride.
18. The rotor system of claim 17 , wherein the layer of solid lubricant includes at least one of molybdenum disulphide and boron nitride and wherein the layer of solid lubricant is baked onto the at least one surface.