Devices and methods for modifying width of rotor aircraft during operational flight

Abstract

Devices, systems, and methods are provided in which a wing of a tiltrotor aircraft is rotated during operational flight, for example from a position perpendicular to the aircraft's fuselage through an angle of 30° or more in the direction of flight. This effectively narrows the maximum width of the aircraft, and facilitates maneuvering through closely spaced obstacles.

Claims

1. A rotorcraft having a direction of flight when the rotorcraft is in flight, comprising: a fuselage; a turntable mounted on the fuselage, a wing mounted on the turntable such that the wing is configured to rotate at least 30° away from away from vertical to the fuselage axis in a top view; a first nacelle with a first tiltrotor mounted on a left side of the wing, and a second nacelle with a second tiltrotor mounted on a right side of the wing; wherein each of the first and second nacelles are tiltable during flight between forward and vertical flight positions; wherein each of the first and second nacelles extend downward from the wing when the rotorcraft is in the vertical flight position; and wherein a top of the fuselage is tapered at the front and the rear of the fuselage to accommodate the first and second nacelles positioned over the fuselage.

2. The rotorcraft of claim 1, wherein when the rotorcraft has a longitudinal axis, and the wing is rotatable on the turntable to a position substantially parallel to the longitudinal axis during flight.

3. The rotorcraft of claim 1, wherein the wing is rotatable on the turntable during flight by at least 30° during flight.

4. The rotorcraft of claim 1, wherein the wing is rotatable on the turntable during flight by at least 45° during flight.

5. The rotorcraft of claim 1, wherein the wing is rotatable on the turntable during flight by 60° during flight.

6. The rotorcraft of claim 1, wherein the wing has a span of at least 80 feet.

7. The rotorcraft of claim 1, wherein the left and right tiltrotors have rotor blades that extend laterally beyond left and right tips of the left and right sides of the wing, respectively.

8. A method of operating an aircraft having a fuselage, a wing coupled to the fuselage, and left and right tiltrotors positioned on the wing, the method comprising: operating the aircraft with the left and right tiltrotors in forward flight mode; and while operating the aircraft, tilting the left and right tiltrotors to a vertical flight mode; and rotating the wing such that the left and right tiltrotors are at least partially positioned over the fuselage.

9. The method of claim 8, wherein the wing is rotated such that a line between the left and right tiltrotors is parallel to a longitudinal axis of the aircraft.

10. The rotorcraft of claim 1, wherein each of the first and second nacelles extend downward from the wing when the rotorcraft is in the vertical flight position, the rotorcraft has a longitudinal axis, and the wing is rotatable on the turntable to a position substantially parallel to the longitudinal axis during flight.

11. The rotorcraft of claim 1, wherein a top of the fuselage is tapered at the front and the rear of the fuselage to accommodate the first and second nacelles positioned over the fuselage.

12. The rotorcraft of claim 11, wherein when the rotorcraft has a longitudinal axis, and the wing is rotatable on the turntable to a position substantially parallel to the longitudinal axis during flight.

Description

DESCRIPTION OF THE FIGURES

(1) FIGS. 1A and 1B: FIG. 1A provides a top-down view of an embodiment of a tiltrotor aircraft of the inventive concept with the wing positioned approximately perpendicular to the fuselage of the aircraft, presenting a maximum wing aspect ratio, where the rotors are positioned at the ends of the wing. FIG. 1B provides a top-down view of a tiltrotor aircraft of FIG. 1A with the wing pivoted about a central point relative to the fuselage of the aircraft, presenting a minimized wing aspect ratio without reducing the distance between the rotors.

(2) FIGS. 2A and 2B provide top down and frontal views of another tiltrotor aircraft as contemplated herein.

(3) FIGS. 3A, 3B, 3C, and 3D provide frontal and perspective views of an embodiment of an unmanned tiltrotor aircraft as contemplated herein.

DETAILED DESCRIPTION

(4) The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

(5) The inventive subject matter provides apparatus, systems and methods in which a rotorcraft has first and second rotors mounted on a wing, and a control system is configured to allow the wing to rotate horizontally during operational flight. Such a wing can be a single element wing, mounted to the tiltrotor aircraft's fuselage at a central point by a rotating or pivoting mechanism. Unlike the pivoting mechanism of the V-22 which is used for folding and takes loads only in high surface wind (on ship) and in taxi, the inventive pivoting mechanism will take flight loads and provide the required stiffness for safe flight dynamics. Alternatively, the inventive subject matter can include independent wing elements joined at one terminus to a central element mounted on the fuselage of a tiltrotor aircraft. The wing elements can support tiltable rotors, and such wing elements can be moved in concert to effectively provide a pivoting wing. Such pivoting wings can be rotated at least 45°, at least 60°, or more than 60° relative to the long axis of the tiltrotor aircraft's fuselage.

(6) Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

(7) The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

(8) As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously.

(9) In some embodiments, a rotorcraft or tiltrotor aircraft of the inventive concept can include first and second rotors mounted on left and right portions of a wing, respectively. The wing can be mounted on a turntable configured to horizontally rotate the wing relative to the aircraft's fuselage. A control system can be configured to utilize the turntable to horizontally rotate the wing during operational flight at angles of at least 45°, at least 60°, or more than 60° relative to the long axis of the fuselage. In some embodiments the wing portion and the associated rotor are rotated together. In other embodiments a nacelle that includes the rotor can be rotated while the wing portion or a segment of the wing portion remains horizontal.

(10) In other embodiments, a rotorcraft or tiltrotor aircraft of the inventive concept can include first and second rotors mounted on left and right wing segments, respectively. Such left and right wing segments are discontinuous, but can move in concert to effectively act as a unitary wing structure. One end of each wing segment can be coupled to a turntable or other rotating structure (such as a rotatable column or shaft) configured to horizontally rotate each wing segment relative to the aircraft's fuselage. A control system can be configured to utilize the turntable to horizontally rotate the wing segments during operational flight so as to provide a continuous wing structure oriented at angles of at least 45°, at least 60°, or more than 60° relative to the long axis of the fuselage. In some embodiments the wing portion and the associated rotor are rotated together. In other embodiments a nacelle that includes the rotor can be rotated while the wing portion or a segment of the wing portion remains horizontal. In another embodiment the control system can be configured to horizontally rotate the wing while simultaneously tilting the rotors.

(11) As noted above, such control systems are preferably configured to horizontally rotate the wing, during operational flight, at least 30° from a first position to a second position, more preferably up to at least 45° from the first position to the second position, and most preferably up to at least 60° from the first position to the second position. In such embodiments the second position provides the tilt rotor aircraft with a reduced wing aspect ratio relative to the first position without altering the distance between the rotors. As such an aircraft so equipped can maintain rotor lift at low operational speeds for maneuvering through closely spaced obstacles that would not be accessible to similar aircraft having fixed wings mounted perpendicular to the fuselage.

(12) An example of an embodiment of a tiltrotor aircraft of the inventive concept is shown in FIGS. 1A and 1B, which depict an exemplary V-22 Osprey rotorcraft 100 modified to provide rotation of the aircraft's wing (along with its terminally mounted rotors). FIG. 1A shows such an aircraft in the first position, which provides maximum wing aspect ratio. FIG. 2B shows such an aircraft in the second position, which provides a reduced or minimized wing aspect ratio. As shown, such an aircraft 100 has a fuselage 110, and left and right rotors 130A, 130B mounted on the ends of a horizontally rotating wing 120. The wing 120 is mounted on a turntable 140, which rotates the wing 120 relative to the fuselage. When the wing 120 is in a first position (shown in FIG. 1A), substantially perpendicular to a long dimension of the fuselage, the flight width 150A of the aircraft 100 is at a maximum (in this example, approximately 84.6 feet). When the wing 120 is in a second position (shown in FIG. 1B) that is pivoted 45° from the first position, the flight width 150B of the aircraft 100 is reduced to approximately 71.0 feet. depict a contemplated aircraft in a three dimensional surface presentation. As shown in the figures, the nacelles of rotors of rotorcraft can be positioned at the outboard ends of the wing. However, it is also contemplated that there could be additional wing outboard of the nacelles.

(13) Although not explicitly shown in the figures, it should be appreciated that in aircraft of the inventive concept the wing 120 of rotorcraft 100 can be further rotated horizontally to at least 60° off from the first position, in which case the flight width 150B of the aircraft 100 is reduced to about 61.3 feet. Such extreme reduction is considered to be viable for helicopter mode of a modified V-22 aircraft, with nacelle tilt angle deviations of 75° to 105°.

(14) In more generalized cases, a rotorcraft according to the inventive concept can include a control system configured to allow the wing to be angled about 30°, about 45°, about 60° or more than about 60° relative to the first position. In preferred embodiments the control system allows the wing to be angled at least 60° from the first position. Accordingly, it is contemplated that tilt-rotorcraft are contemplated as having a flight width no more that 85%, 75%, 70%, 65%. 60%, 55%, 50%, or less than 50% of the maximum flight width when the wing is rotated.

(15) FIGS. 2A and 2B provide top down and frontal views of another tiltrotor aircraft as contemplated herein.

(16) FIGS. 3A, 3B, 3C, and 3D: FIG. 3A provides a top-down view of an embodiment of an unmanned tiltrotor aircraft of the inventive concept with the wing positioned approximately parallel to the fuselage of the aircraft, presenting a minimum wing aspect ratio, where the rotors are positioned inboard of the wing tip. FIG. 3B provides an isometric view of an unmanned tiltrotor aircraft of FIG. 3A with the wing positioned approximately perpendicular to the fuselage of the aircraft. FIG. 3C provides an isometric view of an unmanned tiltrotor aircraft of FIG. 3A with the wing positioned approximately parallel to the fuselage of the aircraft. FIG. 3D provides an isometric view of an alternative embodiment to the aircraft of FIG. 3B.

(17) As can be seen in FIGS. 3C and 3D, 15, the first and second wing segments can extend beyond tips of the first and second rotors, respectively, and can even extend beyond fore and aft ends of the fuselage, respectively.

(18) It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.