Ancillary aerodynamic structures for an unmanned aerial vehicle having ducted, coaxial counter-rotating rotors

• US 5,419,513 A
• Filed: 05/11/1993
• Issued: 05/30/1995
• Est. Priority Date: 05/11/1993
• Status: Expired due to Fees

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Flemming, Robert J. Jr., Rosen, Kenneth M., Sheehy, Thomas W.
• Primary Examiner(s): Barefoot, Galen L.
• Application Number:
  US08/060,337
• Time in Patent Office: 749 Days
• Field of Search: 244/12.2, 244/23 C, 244/36, 244/17.11, 244/45 R, 244/17.19, 244/12.1, 244/23 R
• US Class Current: 244/12.2
• CPC Class Codes: B64C 27/20 Rotorcraft characterised by having shrouded rotors, e.g. flying platforms
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64U 10/13 Flying platforms
• CPC Class Codes: B64U 30/10 Wings
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: B64U 30/24 Coaxial rotors
• CPC Class Codes: B64U 50/14 ducted or shrouded

Abstract

An unmanned aerial vehicle (UAV) having a toroidal fuselage and a rotor assembly including counter-rotating rotors coaxially mounted with respect to the toroidal fuselage incorporates ancillary aerodynamic structures aerodynamically configured and mounted in combination with the toroidal fuselage to provide a nose-down pitching moment to counteract the nose-up pitching moment generated by airflow over the toroidal fuselage during forward translational flight of the UAV. The ancillary aerodynamic structures have a cambered airfoil profile to provide high lifting forces. The ancillary aerodynamic structures may have centers of lift located significantly aft of the quarter-chord line of the airfoil, and are symmetrically mounted in combination with the lateral sides of the toroidal fuselage so that the centers of lift are located aftwardly of the fuselage axis of the toroidal fuselage in forward translational flight modes such that the ancillary aerodynamic structures generate a nose-down pitching moment to counteract the nose-up pitching moment due to airflow over the toroidal fuselage in forward translational flight. In a first embodiment, the ancillary aerodynamic structures are fixedly mounted in combination with the toroidal fuselage at a predetermined angle of incidence. In a second embodiment, the ancillary aerodynamic structures are rotatably mounted in combination with the toroidal fuselage to provide variable incidence ancillary aerodynamic structures for the UAV.

Claims

1. An unmanned aerial vehicle, comprising:

a toroidal fuselage having a coaxial fuselage axis and a longitudinal axis, said toroidal fuselage being fabricated as a closed toroid that is a partially hollow structure that provides a plurality of accessible internal bays and wherein said toroidal fuselage is symmetric with respect to said coaxial fuselage axis and said longitudinal axis, said symmetrical toroidal fuselage defining an inner flow duct, airflow over said symmetrical toroidal fuselage and through said inner flow duct during forward translational flight modes of said unmanned aerial vehicle defining a center of lift for said unmanned aerial vehicle, the airflow causing a nose-up pitching moment on said unmanned aerial vehicle acting through said center of lift;

rotor assembly means for providing collective and cyclic pitch to control flight operations of said unmanned aerial vehicle, said rotor assembly means including a pair of multi-bladed, counter-rotating rotors coaxially mounted in combination with said symmetrical toroidal fuselage in said inner flow duct, said multi-bladed, counter-rotating rotors having an axis of rotation coaxial with said fuselage axis; and

first and second ancillary aerodynamic structures only symmetrically mounted in combination with respective lateral sides of said symmetrical toroidal fuselage, said first and second ancillary aerodynamic structures having a cambered airfoil profile to provide high lifting forces during forward translational flight modes of said unmanned aerial vehicle;

said first and second ancillary aerodynamic structures having centers of lift, and wherein said first and second ancillary aerodynamic structures are symmetrically mounted so that said centers of lift are aft of said fuselage axis during forward translational flight modes of said unmanned aerial vehicle;

said first and second ancillary aerodynamic structures causing an offset of said center of lift of said symmetrical toroidal fuselage along said longitudinal axis thereof during forward translational flight modes of said unmanned aerial vehicle wherein said high lifting forces of said first and second ancillary aerodynamic structures generate a nose-down pitching moment that counteracts the nose-up pitch moment of said symmetrical toroidal fuselage.

2. The unmanned aerial vehicle of claim 1 wherein said first and second ancillary aerodynamic structures are fixedly mounted in combination with said symmetrical toroidal fuselage at a predetermined angle of incidence.

3. The unmanned aerial vehicle of claim 2 wherein said cambered airfoil profile of said first and second ancillary aerodynamic structures is a Clark Y airfoil.

4. The unmanned aerial vehicle of claim 1 wherein said first and second ancillary aerodynamic structures are rotatably mounted in combination with said symmetrical toroidal fuselage to vary an angle of incidence therewith, and wherein said unmanned aerial vehicle further comprises

means for mounting said first and second ancillary aerodynamic structures in rotatable combination with said symmetrical toroidal fuselage, and

means operatively interconnected to said mounting means for controlling rotation thereof,

wherein said mounting means and said controlling means are coactively operative to rotate said first and second ancillary aerodynamic structures to vary said angle of incidence thereof with respect to said symmetrical toroidal fuselage.