Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Reexamination Certificate
1999-05-13
2001-05-08
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
C244S036000, C244S130000, C244S04500R
Reexamination Certificate
active
06227498
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to aircraft aerodynamic control surfaces, and more particularly to an aircraft having an aerodynamic inboard lifting member and a outboard member which selectively move relative to the inboard lifting member.
BACKGROUND INVENTION
Conventional fixed winged aircraft are provided with a variety of aerodynamic control surfaces which include, for example, flaps, elevators, ailerons, trim tabs, and rudders. These control surfaces cooperatively operate to increase or decease lift over a given localized aerodynamic control surface for achieving pitch, yaw and roll control of the aircraft. Such control surfaces are used in both traditional winged aircraft and in modern stealthy designs, such as the delta wing and the F-
117
.
These control surfaces are typically rigid structures which are rotatably attached to the wings or body (i.e., aerodynamic lifting surfaces) of the aircraft in a hinge-like fashion. Operation of the control surfaces typically forms gaps and/or abrupt changes in surface contours at or about the hinge area. Such gaps and abrupt changes are undesirable for a number of reasons. The gaps and abrupt changes tend to increase the drag on the aircraft, give rise to the potentiality that foreign objects and/or debris may become caught thereat, and increase the radar signature of the aircraft.
In addition, conventional control surfaces are usually located at the trailing edges of the wings and fins of the aircraft. In order to operate the control surfaces, the associated actuators and supporting pneumatic piping and/or electrical wiring must also be housed at these locations. Because these locations are typically spatially constrained, assembly and subsequent maintenance of the control surfaces and their actuation mechanisms are complex and labor intensive operations.
It is therefore evident that there exists a need in the art for an aircraft aerodynamic control surface which mitigates gaps and abrupt surface contour changes, and mitigates aircraft radar cross section signature, reduces the complexity of assembly and maintenance operations associated with conventional control surface designs.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an aerodynamic control device for integrated use with an aircraft having an inboard lifting member. The inboard lifting member having a leading edge, a pair of opposing distal edges and a trailing edge. The control device is provided with a movable outboard member which extends substantially about the leading, distal and trailing edges of the inboard lifting member and is spaced apart therefrom. The outboard member is provided with a leading edge portion, a pair of opposing distal edge portions, and a trailing edge portion. The leading, distal, and trailing edge portions are movable in relation to the inboard lifting member to form an airfoil surface extending about the inboard lifting member and the outboard member for achieving aerodynamic control of the aircraft. The trailing edge portion has at least one deflectable segment which is vertically movable in relation to the leading and distal edge portions for achieving further aerodynamic control of the aircraft.
In the preferred embodiment of the present invention, the at least one deflectable segment comprises a pair of deflectable segments. In this respect, the inboard lifting member defines a longitudinal axis and the deflectable segments are symmetrically disposed about the longitudinal axis. The deflectable segments are sized and configured to move in opposing vertical directions and in the same direction.
Preferably, the control device is provided with a flexible transition section. The transition section extends between the inboard lifting member and the outboard member to form a relatively uninterrupted airfoil surface extending about the inboard lifting member and the outboard member for achieving desired aerodynamic control of the aircraft. The transition section may be formed of an elastomeric material. The transition section is attached to the outboard member and the inboard lifting surface in a fashion which does not produce any significant abrupt surface contour changes, such as steps or gaps. Thus, the airfoil surface is relatively continuous and smooth. As such, selective contouring of the airfoil surface, via movement of the outboard member relative to the inboard member and/or movement of the deflectable segment of the trailing edge portion of the outboard member, facilitates single surface aerodynamic control. Moreover, it is contemplated that such aerodynamic control may be generally independent with respect to specific axes of aircraft control (e.g., generally independent roll, yaw and pitch control).
Preferably, the aerodynamic control device is provided with a plurality of actuators mechanically coupling the outboard member to the inboard lifting surface for selectively moving the outboard member relative to the inboard lifting member. In addition, actuators may be engaged with the deflectable segments of the trailing edge portion for moving the segments relative to the rest of the outboard member. The actuators may be electrical, hydraulic and pneumatic devices and combinations thereof.
In the preferred embodiment of the present invention, the outboard member is an unitary uninterrupted member and laterally spans the inboard lifting member. Generally, the outboard member is substantially rigid and may be formed of non-metallic materials, such as a resin composite. A degree of flexure of the outboard member is contemplated. In this regard, the outboard member may formed of a material capable of sustaining an elastic strain of at least 5 percent for facilitating relative movement of the deflectable segments. In contrast, the transition section comprises an elastomeric material.
Advantageously, the aircraft in which the present invention is practiced may be delta-shaped. Other aircraft shapes are contemplated including more traditional designs having a fuselage with fixed wings. Other embodiments of the present invention include incorporating the above described aerodynamic control device into an aircraft wing and fuselage as well as an all wing type aircraft. The wings of the aircraft are provided with wing tips. The distal edges of the inboard lifting member and the distal edge portions of the outboard member are disposed at the wing tips.
In addition, there is provided a method of aerodynamic control of an aircraft comprising the initial step providing an aircraft with an aerodynamic inboard lifting member having a leading edge, a distal edge and a trailing edge as disclosed above. An airfoil surface is formed by positioning the movable outboard member extending substantially about the leading, distal and trailing edges of the inboard lifting member and spaced apart therefrom.
Aerodynamic control of the aircraft is achieved by selectively moving the outboard member relative to the inboard lifting member thereby contouring the airfoil surface for achieving aerodynamic control of the aircraft. Further, at least one deflectable segment of the trailing edge portion is selectively moved relative to the leading and trailing edge portions thereby further contouring the airfoil surface for achieving aerodynamic control of the aircraft. As mentioned above, preferably a pair of deflectable segments is provided. The deflectable segments are symmetrically disposed about a longitudinal axis of the inboard lifting member.
Pitch control of the aircraft may be achieved by moving the leading and trailing edge portions of the outboard member in opposing directions relative to the inboard lifting member along a vertical axis of the inboard lifting member. As such, the outboard member is rotated about an axis which is parallel to a lateral axis of the inboard lifting member. Additionally pitch control may be achieved by a symmetrically disposed deflectable segments in the same relative vertical direction.
In addition, roll and yaw control may be achieved by rotating the outboard membe
Anderson Terry J.
Barefoot Galen L.
Hoch, Jr. Karl J.
Northrop Grumman Corporation
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