Abstract:
The present set of embodiments relate to systems, methods, and apparatuses for airfoil systems designed for aircraft or other craft. More specifically, the present disclosure includes various embodiments of airfoils that include fixed or adjustable louvers that allow the airfoil to adapt to various conditions including angle or attack and airspeed. Such airfoil systems increase the dynamic range or airfoils by maximizing lift or minimizing drag depending on the conditional requirements.

Description:
FIELD 
       [0001]    The present disclosure generally relates to airfoil systems for aircraft. More specifically, airfoil systems that allow for vertical takeoff and horizontal flight. 
       BACKGROUND 
       [0002]    Aircraft rely on airfoils to create aerodynamic lift by creating a difference in pressure above and below the airfoil. On most airfoils, the upper surface is longer than the lower surface, thereby, causing faster airflow above the wing. This results in a lower pressure above the airfoil which causes lift. Generally, airfoils designed for slow flight have a larger upper surface in proportion to the lower surface which creates more lift, but also more drag. Airfoils that are designed for faster flight have a smaller upper surface in proportion to the lower surface and create less drag. High speed airfoils (See  FIG. 1 ) require more power and do not perform well at low speeds. 
         [0003]    At higher angles of attack (AOAs) separation of a boundary layer of air begins to occur at the aft upper section of the wing. The shape of the airfoil determines where, how, at what speed, and how abrupt this separation is. Once the critical AOA is reached, the airfoil will stall. 
         [0004]    Blown wing resultant from induced airflow changes the relative airflow and can increase the allowable AOA from relative motion of the wing. This configuration requires higher power states to drive air over the airfoil with sufficient velocity to increase lift and inhibit boundary layer separation. 
         [0005]    A glider airfoil is another solution. A wing with a long wingspan and short chord (fore and aft), allows for slower speeds. Additional system components such as dihedral wings, stall strips, and winglets are all aimed at achieving a balance between desired lift, stall, drag, and performance. 
         [0006]    What is needed is an airfoil method and system that can adapt to various conditions which will maximize efficiency during low and high speed conditions. Essentially, a method and system that will combine the advantages seen in  FIGS. 1A and 1B  while minimizing the drawbacks. 
       SUMMARY 
       [0007]    In one aspect, an adjustable airfoil system for an aircraft or other craft is disclosed. The adjustable airfoil system can include at least one airfoil. The adjustable airfoil system can include a plurality of louvers forming a portion of the airfoil. The adjustable airfoil system can include a connector configured to connect the plurality of louvers, wherein the plurality of louvers are configured to change conformation based on a force produced by an airflow. 
         [0008]    In one aspect, a method to adjust the aerodynamic properties of an airfoil is disclosed. The method can include flowing air over an airfoil at a first rate. The method can include positioning a plurality of louvers to a first position, wherein the first position corresponds to a first thickness. The method can include flowing air over an airfoil at a second rate. The method can include repositioning the plurality of louvers to a second position, wherein the second position corresponds to a second thickness, wherein the first thickness and the second thickness are not the same. 
         [0009]    In one aspect, an aircraft system configured for vertical takeoff and landing and horizontal flight is disclosed. The system can include a fuselage. The system can include at least one propeller affixed to the fuselage. The system can include an airfoil including at plurality of louvers, wherein the plurality of louvers are configured to change conformation based on a force produced by an airflow. 
         [0010]    In one aspect, a fixed airfoil system is disclosed. The system can include an airfoil configured to generate a lift based on an angle of attack. The system can include a plurality of louvers forming a portion of the airfoil. The system can include a space between each of the plurality of louvers configured to flow an airflow wherein increasing the angle of attack increases the airflow. 
         [0011]    In one aspect, a method of adjusting the aerodynamic properties of an airfoil is disclosed. The method can include flowing air over an airfoil at a first angle of attack to generate a first lift and a first drag. The method can include flowing air through a space at the first angle of attack. The method can include flowing air over an airfoil at a second angle of attack to generate a second lift and a second drag. The method can include flowing air through a space at the second angle of attack causing the second lift and the second drag to decrease relative to the first lift and the first drag. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0012]    For a more complete understanding of the principles disclosed herein, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings in which: 
           [0013]      FIGS. 1A and 1B  are illustrations of airfoil systems according to the prior art. 
           [0014]      FIG. 2  is an illustration of a louver for an airfoil according to one of the various embodiments. 
           [0015]      FIG. 3A  is an illustration of an airfoil system, including a louver system in a closed configuration, according to one of the various embodiments. 
           [0016]      FIG. 3B  is an illustration of an airfoil system, including a louver system in an open configuration, according to one of the various embodiments. 
           [0017]      FIG. 4A  is an illustration of an airfoil system, including a louver system in a closed configuration, according to one of the various embodiments. 
           [0018]      FIG. 4B  is an illustration of an airfoil system, including a louver system in an open configuration, according to one of the various embodiments. 
           [0019]      FIG. 5  is an illustration of a flow diagram according to one of the various embodiments. 
           [0020]      FIG. 6  is an illustration of a flow diagram according to one of the various embodiments. 
       
    
    
       [0021]    While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those skilled in the art. 
         [0022]    Furthermore, in describing various embodiments, the specification may have present a method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process should not be limited to the performance of their steps in the order written, and one of skill in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the various embodiments. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]    Embodiments of systems, methods, and apparatuses for airfoil systems designed for aircraft or other craft are described in the accompanying description and figures. In the figures, numerous specific details are set forth to provide a thorough understanding of certain embodiments. A skilled artisan will be able to appreciate that the airfoil system described herein can be used in a variety of instruments and craft using wing systems and are not limited to aircraft. Additionally, the skilled artisan will appreciate that certain embodiments may be practiced without these specific details. Furthermore, one skilled in the art can readily appreciate that the specific sequences in which methods are presented and performed are illustrative and it is contemplated that the sequences can be varied and still remain within the spirit and scope of certain embodiments. 
         [0024]    While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those skilled in the art. 
         [0025]    In order that the present disclosure may be more readily understood, certain terms are first defined. 
         [0026]    As used herein “about” means plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%. 
         [0027]    As used herein “louver” means a component of an airfoil that may or may not be adjustable and contributes the size of an upper and lower surface of an airfoil. 
         [0028]    In the aerospace field various wing or airfoil designs are used for various applications. Generally, a single type of airfoil is designed for a single purpose. Referring to  FIG. 1A , an illustration of a prior art design depicts an airfoil system adapted for low aircraft speed and high lift generation. Referring to  FIG. 1B , an illustration of a prior art design depicts an airfoil system adapted for high aircraft speed and lower lift generation with the advantage of less drag. One example of an aircraft utilizing the airfoil depicted in  FIG. 1A  could be a low speed, unpowered aircraft. One example of an aircraft utilizing the airfoil depicted in  FIG. 1B  could be a higher speed propeller driven aircraft relying on increased airflow generation. An improved airfoil system could harness the advantages of both the airfoil systems disclosed in  FIGS. 1A and 1B  while minimizing the disadvantages. 
         [0029]    One embodiment of a solution to the problem presented in  FIGS. 1A and 1B  is a use of a louver system  200  in an airfoil system as illustrated in  FIG. 2 . 
         [0030]    As shown in  FIG. 2 , the louver system  200  comprises at least one attachment  202 , at least one connected  203 , at least one upper louver  204 , at least one lower louver  206 , at least one surface of the upper louver  208 , at least one surface of the lower louver  210 , at least one upper end, at least one lower end, at least one upper length  216 , and at least one lower length  218 . 
         [0031]    In various embodiments, the louver system  200  can comprise one or more attachments  202 . The attachment  202  can function to attach one or more louvers  201  to one or more connectors  203 . When in use, the louver system  202  can use one or more forces to position the louvers  201  in various positions. The connector  203  can be used to ensure that when more than one louver  201  is incorporated into the system they are positioned relative to one another. 
         [0032]    In various embodiments, the louver  201  will have an upper end  212  and a lower end  214  that can be positioned in based on a mechanical force in conjunction with an airflow. The louver  201  can be rotate around the axis or location of the attachment  202 . 
         [0033]    In various embodiments, the louver  201  can have an upper length  216  and a lower length  218 . In some embodiments the upper length  216  can be longer than the lower length  218 . In some embodiments the upper length  216  can be the same as the lower length  218 . In some embodiments the upper length  216  can be shorter than the lower length  218 . 
         [0034]    As shown in  FIGS. 3A and 3B , the louver system  200  can be integrated into an airfoil to comprise a closed configuration  301  and an open configuration  3001 . The airfoils depicted in  FIGS. 3A and 3B  comprise a leading edge  302   3002 , a trailing edge  304   3004 , a chord  306   3006 , a thickness  308   3008 , an upper camber  310   3010 , a lower camber  312   3012 , and an upper surface  314   2014 . The two configuration depicted do not comprise all configurations as there are an infinite number of intermediate positions. 
         [0035]    In various embodiments, a mechanical force can be overcome by a force generated by an airflow which can result in the louver system  200  configuring to change from an open configuration  3001  to a closed configuration  301  as seen in  FIGS. 3A and 3B . 
         [0036]    In various embodiments, the leading edge  302  and trailing edge  304  in the close configuration can stay in the same locations as the leading edge  3002  and the trailing edge  3004  in the open configuration  3001 . In some embodiments, the chord length  306  in the open configuration  3001  can stay the same as the chord length  3006  in the closed configuration  3001 . 
         [0037]    In some embodiments, the airfoil thickness  308  is decreased in the closed configuration  301  when compared to the airfoil thickness  3008  in the open configuration  3001 . 
         [0038]    In various embodiments, the airfoil upper camber  310  and lower camber  312  are decreased in the closed configuration  301  as compared to the upper camber  3010  and lower camber  3012  in the open configuration  3001 . In some embodiments the ratio of the upper camber  310  and lower camber  312  in the closed configuration  301  is the same, smaller or larger when compared to the ratio of the upper camber  3010  and lower camber  3012  in the open configuration  3001 . 
         [0039]    In various embodiments, the upper surface  314  and the lower surface  316  are both in the closed configuration  301  are both reduced when compared to the upper surface  3014  and the lower surface  3016  of the open configuration  3001 . 
         [0040]    As shown in  FIGS. 4A and 4B , the louver system  200  can be integrated into an airfoil to comprise a closed configuration  400  and an open configuration  4000 .  FIG. 4  illustrates a detailed view of the inner workings of  FIG. 3  and can comprise at least one mechanical force generator  404   4004 , at least one connector  406   4006 , at least one attachment  408   4008 , at least one space  410   4010 , and at least one louver  412   4012 . 
         [0041]    In various embodiments, the airflow direction caused by the angle of attack  402  over the airfoil in the close configuration  400  can overcome the mechanical force generator  404 , thereby, causing the louvers  412  to rotate counter clockwise as depicted in  FIGS. 4A and 4B . The connector  406  ensures that all the louvers  412  conform to their predefined positions aided through an attachment  408 . In some embodiments, the space  410  in the close configuration  400  is narrow. Different louver systems can respond to different airflow forces based on the ratio of the upper length  216  to the lower length  218 . 
         [0042]    In various embodiments, the airflow direction caused by the angle of attack  4002  over the airfoil in the open configuration  4000  can fail to overcome the mechanical force generator  4004 , thereby, causing the louvers  4012  to rotate clockwise as depicted in  FIGS. 4A and 4B . In some embodiments, the space  4010  in the open configuration  4000  is wider than the space  410  in the closed configuration  400 . In various embodiments, the airfoil can comprise a shroud or a skin configured to cover the space  410 . 
         [0043]    In various embodiments, the mechanical force generator  404  can comprise at least one spring, at least one pneumatic device, at least one screw, at least one electrical actuator, or at least one hydraulic device. 
         [0044]    In various embodiments, the louver systems  200  in  FIGS. 4A and 4B  can be fixed instead of adjustable as depicted in previous embodiments. In such systems, airfoil properties are dependent on the angle of attack. For example, the angle of attack  402  would result in efficient lift and decreased drag. The angle of attack  4002  seen in  FIG. 4B  on the same air foil would result in decreased separation of a boundary layer than would normally occur using conventional airfoil systems. This occurs due to the space  410   4010  provided by the louver system  200 . Such louver systems  200  presented herein have a broader dynamic range than convention airfoil systems. During cruise flight airflow can bypass the spaces  410   4001  or channels due to Venturi effect. During takeoff, climbing, and landing (high AOA) more air can flow through the spaces  410   4010  or channels, thereby, increasing lift over the airfoil or wing and decreasing boundary layer separation. 
         [0045]      FIG. 5  is an exemplary flowchart showing a method  500  for utilization of a louver system in an airfoil. 
         [0046]    In step  502 , air flows over an airfoil at a first rate. In step  504 , one or more louvers are positioned to a first position, wherein the first position corresponds to a first thickness. In step  506 , air flows over an airfoil at a second rate. In step  508 , the one or more louvers can be repositioned, wherein the second position corresponds to a second thickness, wherein the first thickness and the second thickness are not the same. 
         [0047]    In various embodiments, an additional step can include flowing air through a space between two of the plurality of louvers. 
         [0048]    In various embodiments, an additional step can include positioning a connector  406   4006  to a first position. Another additional step can include positioning the connector  406   4006  to a second position. The connector can be affixed to each of the plurality of louvers to ensure that each of the plurality of louvers configures to a conformation relative to each of the other louvers. 
         [0049]    In various embodiments, flowing airflow at the second rate generates a force to overcome a mechanical force. The mechanical force can be created by a mechanical force generator  404   4004 . In some embodiments, the mechanical force can be generated by a spring, pneumatic device, electrical device, hydraulic device, or any other device known or useful in the art. 
         [0050]    In various embodiments, the second airflow rate can be greater than the first airflow rate and the first thickness can be greater than the second thickness. In some embodiments, the overall airfoil can have more curvature at the first airflow rate compared to the second airflow rate. 
         [0051]      FIG. 6  is an exemplary flowchart showing a method  600  for utilization of a fixed louver system in an airfoil. Such an embodiment does not allow for adjustable louvers and lift and drag properties change according to the angle of attack. 
         [0052]    In step  602 , air flows over an airfoil at a first angle of attack to generate a first lift and a first drag. In step  604 , air flows through a space at the first angle of attack. In step  606 , air flows over an airfoil at a second angle of attack to generate a second lift and a second drag. In step  608 , air flows through a space at the second angle of attack causing the second lift and the second drag to decrease. 
         [0053]    In various embodiments, air does not flow through the space at the first angle of attack or can flow through at a much lower rate than at the second angle of attack. 
         [0054]    In various embodiments, an additional step can include decreasing flow separation by increasing airflow through the space. 
         [0055]    As shown in  FIGS. 4A and 4B , the louver system  200  can be integrated into an airfoil to comprise a closed configuration  400  and an open configuration  4000 .  FIG. 4  illustrates a detailed view of the inner workings of  FIG. 3  and can comprise at least one mechanical force generator  404   4004 , at least one connector  406   4006 , at least one attachment  408   4008 , at least one space  410   4010 , and at least one louver  412   4012 . 
         [0056]    As shown in  FIG. 7 , an aircraft system  700  can incorporate a louver system to increase the efficiency of for vertical takeoff and landing and horizontal flight. The aircraft system  700  can comprise at least one louver fuselage  708 , at least one propeller  706 , at least one airfoil  704  that can include at least one louver  702 , wherein the at least one louver is configured to change conformation based on a force produced by an airflow. 
         [0057]    In various embodiments, the aircraft system  700  can incorporate the teachings of the louver system  200  disclosed herein. 
         [0058]    In various embodiments, the propeller can be shrouded. 
         [0059]    While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those skilled in the art.