초록 ▼

A fairing system may be assembled about a rotor of a rotorcraft to present an aerodynamically quasi-static region that rotates in an airstream, as well as certain extensions that sweep through the airstream as the rotor hub passes through the air. A spherical interface between the extensions on the

A fairing system may be assembled about a rotor of a rotorcraft to present an aerodynamically quasi-static region that rotates in an airstream, as well as certain extensions that sweep through the airstream as the rotor hub passes through the air. A spherical interface between the extensions on the rotor hub fairing and the base or root portion of each blade fairing provides three degrees of freedom permitting lead-lag, flapping, and blade pitch pivoting in the blade, while still maintaining an aerodynamic profile that will minimize drag.

대표청구항 ▼

1. An apparatus comprising: a rotorcraft comprising an airframe, a power plant connected to the airframe, and a rotor supported by the airframe, and powered by the power plant, the rotor comprising a hub portion and blades extending from the hub portion operating as rotary wings;a hub fairing comple

1. An apparatus comprising: a rotorcraft comprising an airframe, a power plant connected to the airframe, and a rotor supported by the airframe, and powered by the power plant, the rotor comprising a hub portion and blades extending from the hub portion operating as rotary wings;a hub fairing completely enclosing the hub of the rotor against the airframe to provide a substantially completely enclosed aerodynamic structure about the hub;a blade fairing extending from proximate the hub fairing and extending along a blade presenting an aerodynamic shape, closed against flow therethrough by ambient air;the hub fairing further comprising a plurality of extensions, each extension including a convex spherical surface matched to a proximal surface of the blade fairing;the blade fairing further comprising a concave spherical surface disposed at the proximal end thereof and mated to the convex spherical surface of the hub fairing to substantially preclude passage of air therethrough; anda seal extending between the hub fairing and the blade fairing to resist entry of material into the space between the hub fairing and the blade fairing. 2. The apparatus of claim 1, wherein: the rotorcraft is selected from an autogyro, a gyrodyne, a gyroplane, and a heliplane; andthe seal is formed of an elastomeric material. 3. The apparatus of claim 1 wherein the rotor further comprises a pitch changing element operating to change the pitch of the blade, the pitch change element extending through the extension of the hub fairing without contacting the hub fairing. 4. The apparatus of claim 1 wherein the blade fairing is secured by fasteners to form a continuous aerodynamic surface with a portion of the blade, selectively removable therefrom without removal of the blade or the hub. 5. The apparatus of claim 1 wherein the airframe further comprises a skin disposed over the outside of the airframe to provide an aerodynamic surface, the skin providing with the hub fairing an enclosure, extending to the blades, substantially completely enclosing the hub therein. 6. The apparatus of claim 1 wherein the rotorcraft further comprises a control system extending through the airframe and into the rotor hub, the control system comprising actuators extending upward through the hub, and completely enclosed by the hub fairing and the airframe. 7. The apparatus of claim 1 further comprising the blade fairing having a base portion proximate the hub, and an end portion spaced away therefrom; the hub fairing further comprising an extension opening formed to describe a circle and passing a root of the blade therethrough without contact; andthe blade fairing, wherein the spherical surface is contoured to have a spherical radius less than a spherical radius corresponding to the face portion of the blade fairing, the difference in radii therebetween constituting a clearance between the blade fairing and the hub fairing during flight. 8. The apparatus of claim 7 wherein: the rotorcraft further comprises a control system extending through the airframe and into the rotor hub, the control system comprising actuators extending upward through the hub, and completely enclosed by the hub fairing and the airframe; andthe hub fairing is formed of portions, each selectively attachable and removable, to expose the control system for at least one of maintenance, repair, and inspection, without removal or disassembly of the rotor hub. 9. The apparatus of claim 8, wherein the hub fairing and blade fairing each comprise fasteners selectively securable thereto and removable therefrom to expose at least one of the top of the rotor hub, the bottom of the rotor hub, both the top and bottom of the rotor hub, and the blade root, in a manner adapted to at least one of maintenance, inspection, and repair. 10. The apparatus of claim 1, where each blade of the blades further comprise a blade spar extending through the hub fairing and blade fairing and rotatably mounting to the hub such that the blade spar is rotatable about an axis extending radially outwardly from the hub, the blade spar flexing responsive to flapping and lead-lag loads on the each blade. 11. A method for reducing aerodynamic drag on a rotorcraft, the method comprising; providing a rotorcraft having an airframe, power plant, and rotor, the rotor including a hub portion and blade portion operating as rotary wings;providing a hub fairing substantially enclosing the hub portion of the rotor between the hub fairing and the airframe, the hub fairing defining an outwardly facing convex surface;providing a blade fairing mated to provide three degrees of freedom about a center of rotation, the center of rotation being within the hub fairing, in order to provide the three degrees of freedom of motion of the blade fairing secured to the blade portion of the rotor, without contacting the hub fairing, the blade fairing defining a concave surface interfacing with the outwardly facing convex surface of the hub fairing; andoperating the rotorcraft;operating the rotorcraft with vertical flapping motions of the blades with respect to the hub;operating the rotorcraft with lead-lag bending of each of the rotor blades with respect to the hub; andpitching each of the blades at a variety of angles between a maximum angle of attack and a minimum angle of attack by pivoting the blades with respect to the hub, the blades pivoting without contact with the hub fairing. 12. A method of controlling aerodynamic drag on a rotorcraft, the method comprising providing a rotorcraft having airframe, power plant, and a rotor, the rotor further comprising a hub having airfoils extending therefrom and operating as blades providing lift to the rotorcraft; providing a hub fairing to reduce the aerodynamic drag on air passing by the hub, by directing air around the outside of the hub, and restricting air against passing through the hub, the hub fairing defining an outwardly facing convex spherical surface;providing a blade fairing extending around a root of a blade, the blade fairing matingly fitted to an extension of the hub fairing, the extension terminating in a concave spherical surface, and the blade fairing having a base beginning with the spherical surface, the outwardly facing convex spherical surface of the hub and the spherical surface of the blade being matched to move in three degrees of freedom with respect to one another without contact, the outwardly facing convex spherical surface being inserted within the concave spherical surface. 13. The method of claim 12 further comprising providing an elastomeric seal extending between the spherical surface of the hub fairing and the corresponding surface of the spherical blade fairing. 14. The method of claim 13 further comprising providing the elastomeric seal, wherein the seal is a convoluted bellows providing three degrees of freedom of motion between a first end of the bellows and a second end of the bellows, the first end being connected to the hub fairing and the second end being connected to the blade fairing. 15. The method of claim 12 further comprising assembling the blade fairing from at least two separate components. 16. The method of claim 15 further comprising disassembling the blade fairing into at least the two separate components. 17. The method of claim 12 further comprising disassembling the hub fairing into at least the two separate components. 18. The method of claim 12 further comprising: the providing a hub fairing, further comprising providing a top portion and a bottom portion thereof, the bottom portion comprising at least two selectively attachable and detachable portions;removing the bottom portion from the hub; andservicing the hub. 19. The method of claim 18 further comprising: the providing a blade fairing, further including providing an airfoil positionable around a root of a blade of the blades to form an airfoil therearound; andservicing the blade root by removing the blade fairing, without removing the blade from the hub. 20. The method of claim 19 further comprising substantially completely enclosing the hub and blade roots of the blades by assembling the hub fairing and blade fairing about the hub and blades respectively, without removal of the hub or blade.