Abstract:
A rotor blown wing (RBW) aircraft including an airframe, at least one rotor blown wing (RBW) having at least control selectively controllable surface, at least one rotor configured to generate and direct an airflow over the at least one RBW, and a control system operatively connected to the at least two selectively controllable control surfaces. The control system selectively controls the at least one selectively controllable control surface to change the airflow over the at least one RBW to facilitate a vertical landing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/246,357, which was filed on Oct. 26, 2015. The entire contents of U.S. Provisional Patent Application No. 62/246,357 are incorporated herein by reference. 
     
    
     STATEMENT OF FEDERAL SUPPORT 
       [0002]    This invention was made with Government support under HR0011-14-C-0010 awarded by the Defense Advanced Research Projects Agency (DARPA). The Government has certain rights in the invention. 
     
    
     BACKGROUND 
       [0003]    Exemplary embodiments pertain to the art of rotor blown wing aircraft and, more particularly, to a rotor blown wing aircraft including a rotor blown wing having at least one selectively controllable control surface. 
         [0004]    Rotor blown wing (RBW) includes at least one wing and one or more proprotors. The proprotors generate a downwash that is passed over the wing to increase net wing lift. Accordingly, a RBW aircraft may hover like a rotary wing aircraft and also fly/cruise on the wing(s) as a conventional, fixed wing, aircraft. During hover, in light winds, wind relative to the wing may be at or near stall. Aircraft attitudes necessary to maintain position over a desired landing location may exceed landing capabilities, including the aircrafts&#39; design attitude, thereby limiting an overall operational envelope of the aircraft. 
       BRIEF DESCRIPTION 
       [0005]    Disclosed is a rotor blown wing (RBW) aircraft including an airframe, at least one rotor blown wing (RBW) having at least one selectively controllable control surface, at least one rotor configured to generate and direct an airflow over the at least one RBW, and a control system operatively connected to the at least one selectively controllable control surface. The control system selectively controls the at least one selectively controllable control surface to change the airflow over the at least one RBW to facilitate a vertical landing. 
         [0006]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the at least one RBW includes a leading edge and a trailing edge, the at least one selectively controllable control surface being arranged at the trailing edge. 
         [0007]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the at least one RBW includes a leading edge and a trailing edge, the at least one selectively controllable control surface being arranged at the leading edge. 
         [0008]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the at least one selectively controllable control surface includes a first selectively controllable control surface arranged on a first side of the at least one RBW and a second selectively controllable control surface arranged on a second, opposing side of the at least one RBW. 
         [0009]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the controller selectively independently controls a position of the at least one of the first and second selectively controllable control surfaces to change the airflow over the at least one RBW. 
         [0010]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include a sensor operatively coupled to the control system, the control system controlling the at least one selectively controllable control surface based on the positional changes of the RBW aircraft sensed by the sensor. 
         [0011]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the sensor comprises an inertial sensor. 
         [0012]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the inertial sensor comprises an embedded GPS/Inertial (EGI) sensor. 
         [0013]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the sensor comprises a trim sensor. 
         [0014]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the at least one RBW includes a first RBW portion extending between the airframe and the at least one rotor and a second RBW portion extending outboard of the at least one rotor, the at least one selectively controllable control surface including at least one first selectively controllable control surface associated with the first RBW portion and at least one second selectively controllable control surface associated with the second RBW portion. 
         [0015]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein the at least one first selectively controllable control surface includes at least two first selectively controllable control surfaces and the at least one second selectively controllable control surface includes at least two second selectively controllable control surfaces. 
         [0016]    Also disclosed is a method of controlling an attitude of a rotor blown wing (RBW) aircraft including at least one rotor blown wing (RBW) having at least one selectively controllable control surface. The method includes generating an airflow over the RBW, sensing an attitude of the RBW aircraft, and changing the airflow over the RBW by selectively activating the at least one selectively controllable control surface, and vertically landing the RBW aircraft. 
         [0017]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein sensing the attitude of the RBW aircraft includes monitoring aircraft trim changes. 
         [0018]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein activating the at least one selectively controllable control surface includes changing the airflow over the RBW wing to compensate for the trim changes. 
         [0019]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein sensing the attitude of the RBW aircraft includes sensing inertial changes in the RBW aircraft through one or more signals received from inertial sensors. 
         [0020]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein sensing inertial changes in the RBW aircraft includes receiving one or more signals from an embedded GPS/Inertial (EGI) sensor. 
         [0021]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein selectively activating the at least one selectively controllable control surface includes selectively independently activating at least two selectively controllable control surfaces arranged at a trailing edge of the RBW. 
         [0022]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein selectively activating the at least one selectively controllable control surface includes selectively independently activating at least two selectively controllable control surfaces arranged at a leading edge of the RBW. 
         [0023]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein selectively activating the at least one selectively controllable control surface includes selectively independently activating at least two control surfaces arranged at a leading edge of the RBW and selectively independently activating at least two selectively controllable control surfaces arranged at a leading edge of the RBW wing. 
         [0024]    In addition to one or more of the features described above or below, or as an alternative, further embodiments could include wherein selectively activating the at least one selectively controllable control surface includes selectively activating a first selectively controllable control surface arranged along the RBW between an airframe and a rotor and a second selectively controllable control surface arranged along the RBW outboard of the rotor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0026]      FIG. 1  is perspective view of a rotor blown wing (RBW) aircraft including a rotor blown wing (RBW) including at least one selectively controllable control surface, in accordance with an exemplary embodiment; 
           [0027]      FIG. 2  is an end view of the RBW of  FIG. 1  depicting deployment of a first two selectively controllable control surfaces, in accordance with an aspect of an exemplary embodiment; 
           [0028]      FIG. 3  is an end view of the RBW of  FIG. 1  depicting deployment of a second two selectively controllable control surfaces, in accordance with another aspect of an exemplary embodiment; 
           [0029]      FIG. 4  is an end view of the RBW of  FIG. 1  depicting deployment of a third two selectively controllable control surfaces, in accordance with another aspect of an exemplary embodiment; and 
           [0030]      FIG. 5  is an end view of the RBW of  FIG. 1  depicting deployment of a fourth two selectively controllable control surfaces, in accordance with yet another aspect of an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0032]    A rotor blown wing (RBW) aircraft, in accordance with an exemplary embodiment, is indicated generally at  2  in  FIG. 1 . RBW aircraft  2  includes an airframe  4  that supports a first RBW  6  and a second RBW  8 . As each RBW  6  and  8  is substantially similarly constructed, a detailed description will follow with reference to RBW  6  with an understanding that RBW  8  may include similar details. RBW  6  may include a first RBW portion  10  and a second RBW portion  12  separated by a nacelle  14 . First RBW portion  10  is arranged inboard of nacelle  14 . 
         [0033]    In the exemplary embodiment shown, nacelle  14  supports a rotor  16  as well as a plurality of landing supports indicated generally at  18 . As will be appreciated more fully below, it should be understood that RBW aircraft  2  may include a RBW wing uninterrupted by a nacelle and/or a rotor. Each RBW portion  10  and  12  includes a corresponding leading edge  21  and  22  and a trailing edge  24  and  25 . In accordance with an aspect of an exemplary embodiment, leading edge  21  of first RBW portion  10  may include one or more selectively controllable control surfaces  27 . Similarly, trailing edge  24  of first RBW portion  10  may include one or selectively controllable more control surfaces  28 . An additional one or more selectively controllable control surfaces  29  may be arranged between leading edge  21  and trailing edge  24 . In accordance with another aspect of an exemplary embodiment, leading edge  22  of second RBW portion  12  may include one or more selectively controllable control surfaces  30 . Similarly, trailing edge  25  of second RBW portion  12  may include one or more selectively controllable control surfaces  31 . An additional one or more selectively controllable control surfaces  32  may be arranged between leading edge  22  and trailing edge  25 . At this point, it should be understood that the number and location of control surfaces may vary. 
         [0034]    In further accordance with an exemplary embodiment, RBW aircraft  2  includes a control system  40  which operates to selectively and independently, deploy one or more of control surfaces  27 ,  28 ,  29  and  30 ,  31 ,  32  to facilitate a vertical landing. That is, control system  40  may deploy one or more of control surfaces  27 ,  28 ,  29  and/or  30 ,  31 ,  32  to bring RBW aircraft  2  to rest on landing supports  18 . Control system  40  is also operatively connected to one or more sensors  44  that may detect an orientation of RBW aircraft  2  and/or air currents impinging upon first and second RBWs  6  and  8 . In accordance with an aspect of an exemplary embodiment, one or more sensors  44  may include an inertial sensor  46 . In accordance with another aspect of an exemplary embodiment, inertial sensor  46  may take the form of an embedded GPS/Inertial (EGI) sensor. In accordance with yet another aspect of an exemplary embodiment, sensors  44  may include a trim sensor  48  that senses changes in trim responsive to external forces on RBW aircraft  2 . 
         [0035]    In accordance with an aspect of an exemplary embodiment, control surfaces  28  take the form of first and second control surfaces or flaps  54  and  55  arranged at trailing edge  24  of first RBW portion  10 , as shown in  FIG. 2 . First flap  54  may be arranged on a first side (not separately labeled) of RBW portion  10  and second flap  55  may be arranged on a second, opposing side (also not separately labeled) of RBW portion  10 . Control system  40  may selectively activate one, the other, or both of flaps  54  and  55  to facilitate changes in an orientation of airframe  4  in order to facilitate a vertical landing. Specifically, control system  40  may selectively activate one, the other, or both of flaps  54  and/or  55  to change, e.g., spoil, alter, adjust an airflow over RBW portion  10  in order to counteract forces that may tend to hinder a vertical landing. Similarly, control surfaces  31  take the form of flaps, one of which is indicated at  56  on trailing edge  25  of second RBW portion  10 . 
         [0036]    In accordance with another aspect of an exemplary embodiment, control surfaces  30  take the form of first and second control surfaces or flaps  59  and  60  arranged at leading edge  22  of second RBW portion  12 , as shown in  FIG. 3 . First flap may be arranged on the first surface of RBW portion  12  and second flap  59  may be arranged on the second, opposing surface of RBW portion  12 . Control system  40  may selectively activate one, the other, or both of flaps  59  and  60  to facilitate changes in an orientation of airframe  4  in order to facilitate a vertical landing. Specifically, control system  40  may selectively activate one, the other, or both of flaps  59  and/or  60  to change, e.g., spoil, alter, adjust an airflow over RBW portion  10  in order to counteract forces that may tend to hinder a vertical landing. 
         [0037]    In accordance with another aspect of an exemplary embodiment, control surfaces  32  take the form of first and second control surfaces or flaps  61  and  62  arranged between leading edge  22  and trailing edge  25  of each surface (not separately labeled) of RBW portion  12 , as shown in  FIG. 4 . Control system  40  may selectively activate one, the other, or both of flaps  61  and  62  to facilitate changes in an orientation of airframe  4  in order to facilitate a vertical landing. Similarly, control surfaces  29  may include first and second flaps, one of which is indicated at  63  in  FIG. 1 , that are selectively controllable to change an airflow over first RBW portion  10  to facilitate a vertical landing. Specifically, control system  40  may selectively activate one, the other, or both of flaps  61 ,  62 , and/or flaps  63  to change, e.g., spoil, alter, adjust an airflow over RBW portion  10  in order to counteract forces that may tend to hinder a vertical landing. 
         [0038]    Still further, control surfaces  27  may take the form of first and second control surfaces or flaps  64  and  65  arranged at leading edge  21  of first RBW portion  10 , as shown in  FIG. 5 . Likewise control surfaces  30  may take the form of first and second flaps, one of which is indicated at  67  in  FIG. 1 . Control system  40  may selectively activate one, the other, or both of flaps  64  and  65  and/or  67  to facilitate changes in an orientation of airframe  4  in order to facilitate a vertical landing. Specifically, control system  40  may selectively activate one, the other, or both of flaps  64 ,  65 , and/or flaps  67  to change, e.g., spoil, alter, adjust an airflow over RBW portion  10  in order to counteract forces that may tend to hinder a vertical landing. Additionally, it should be understood, that leading edge  22  of second RBW portion  12  may include one or more selectively controllable flaps (not separately labeled). 
         [0039]    In accordance with exemplary aspects, control system  40  receives inputs from one or more of sensors  44  regarding an orientation of airframe  4  relative to, for example, ground. Deviations in airframe orientation may result from winds, rotor operation, and the like. In order to account for various external forces on airframe  4 , control system  40  selectively activates one or more of control surfaces  27 ,  28 , and  30 ,  31  in order to change, spoil and/or alter an airflow over RBW  6  to control lift, create drag, and facilitate attitude correction moments thereby allowing RBW aircraft  2  to come to rest on landing supports  18 . 
         [0040]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
         [0041]    While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.