Patent Publication Number: US-2020283130-A1

Title: Active winglet

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/707,991, filed Sep. 18, 2017, which is a continuation of U.S. patent application Ser. No. 14/222,437, entitled “Active Winglet”, filed Mar. 21, 2014, which claims the benefit of U.S. patent application Ser. No. 13/075,934, entitled “Active Winglet,” filed Mar. 30, 2011, which claims the benefit of U.S. patent application Ser. No. 12/797,742 entitled “Active Winglet,” filed Jun. 10, 2010 and now abandoned, which claims the benefit of U.S. Provisional Patent Application No. 61/265,534 entitled “Active Winglet,” filed on Dec. 1, 2009, all of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     There exists an ever growing need in the aviation industry to increase aircraft efficiencies and reduce the amount of fossil fuels consumed. Winglets have been designed and installed on many aircraft including large multi-passenger aircrafts to increase efficiency, performance, and aesthetics. Such winglets usually consist of a horizontal body portion that may attach to the end of a wing and an angled portion that may extend perpendicularly from the horizontal body portion. For example, a winglet may be attached to a pre-existing wing of an aircraft to increase flight efficiency, aircraft performance, or even to improve the aesthetics of the aircraft. 
     However, the cost to install a winglet on an aircraft is often prohibitive due to the requirement to engineer and certify the wing after the wing is installed. Thus, aftermarket installation of winglets has generally been reserved for large aircrafts owned and operated by large aircraft companies. 
     Existing winglets have limited utility, in that each winglet must be designed and certified for a specific wing of a specific aircraft model. Additionally, existing winglets, which are fixed, are unable to adapt to changes in in-flight conditions. Accordingly, there remains a need in the art for improved aircraft winglets. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. 
         FIG. 1  depicts an illustrative active winglet attachable to a wing of an aircraft. 
         FIG. 2  depicts an illustrative aircraft with an attached active winglet. 
         FIG. 3  depicts the illustrative active winglet of  FIG. 1  and a cross-sectional view of the active winglet, taken along line A-A of  FIG. 3 . 
         FIG. 4  depicts an illustrative cross-section of the active winglet of  FIG. 1  with a mechanical control system. 
         FIG. 5  depicts an illustrative cross-section of the active winglet of  FIG. 1  with a computer controlled control system. 
         FIG. 6  depicts a design load comparison graph. 
         FIG. 7  depicts a design stress and moment load comparison graph. 
         FIG. 8  depicts a flowchart illustrating details of a controllable airflow modification device. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     This application describes active winglets for improving the efficiency, performance, and aesthetics of an aircraft as well as decreasing the certification cost and time. Active winglets may include controllable airflow modification devices. By virtue of having controllable airflow modification devices, such active winglets may be able to adjust edges and/or portions of the control surfaces of a controllable airflow modification device in response to in-flight load factor data and flight condition data. 
     As discussed above, adding winglets to an existing wing improves airplane efficiency and performance by reducing drag. This performance benefit comes at the cost of adding additional stress to the wing that was not accounted for by the original airplane manufacturer. As a result, installing traditional passive winglets on airplanes is expensive because the wing must be fully analyzed, reverse engineered, and tested to determine if the wing has the structural ability to accommodate the addition of winglets. In most cases, structural wing modifications are required. In all cases, the useful life (fatigue life) of the wing is reduced, thereby increasing the total cost of airplane ownership to the customer. In contrast, the active winglets described herein reduce the engineering and certification costs because active winglets have a minimal (potentially even beneficial) structural effect while maintaining a positive aerodynamic effect. As previously noted, an active winglet according to this disclosure may have an airflow control system in the form of a controllable airflow modification device located on the winglet. This controllable airflow modification device located on the winglet may be adjusted, which may change the aerodynamic forces on the aircraft wing. 
     The active winglet on an aircraft may be designed to keep spanwise section loads at or below originally designed values for a given wing without a winglet. Thus, the active winglet may eliminate the requirement to have a wing reinforced due to the addition of the winglet. Additionally, the controllable airflow modification device of the active winglet may be configured to reduce the bending moment of the wing by moving the center of pressure of the wing inboard and/or reduce the impact of the winglet on the fatigue life of the wing. Therefore, the addition of the active winglet may not significantly decrease, if at all, the service life of the wing and/or the aircraft to which it is attached. In some instances, addition of an active winglet may even reduce fatigue and increase an overall service life of the wing and/or the aircraft to which it is attached. Additionally, in the same or other instances, addition of an active winglet may also increase the overall capacity of the wing carrying capability of the aircraft, thus increasing the aircraft&#39;s gross weight potential. 
     Illustrative Active Winglet 
       FIG. 1  depicts an illustrative active winglet  100  which may be attachable to a wing  102  of an aircraft (not shown). In one embodiment, the active winglet  100  may include a body portion  104  which may be substantially parallel to a horizontal plane and/or a wing of an aircraft. By way of example only, and not limitation, the active winglet  100  may also include an angled portion  106  on the outer side of the body portion  104  and an attachable portion  108  on the inner side of the body portion  104 . In this example, the outer and inner sides of the body portion  104  are described with relation to the wing  102  such that the outer side is further from the wing  102  than the inner side. Additionally, the angled portion  106  may be substantially vertical in relation to the body portion  104  such that it projects perpendicularly from the body portion  104 . However, in other embodiments, the angled portion  106  may be configured to project from the body portion  104  at angles other than 90 degrees. In yet other embodiments, the angled portion  106  may be configured to project from the body portion  104  at angles which include projecting downward (in relation to the aircraft). Additionally, although the angled portion  106  is described above as projecting from the outer side of the body portion  104 , the active winglet  100  may be designed such that the angled portion  106  may project from the middle, or any other location, of the body portion  104  (i.e., the angled portion  106  may be located at any location between the inner and outer sides of the body portion  104 ). 
     The active winglet  100  may include a controllable airflow modification device  110  in the form of one or more control surfaces  112  located on the body portion  104  and/or the angled portion  106 . By further way of example, in one embodiment, the controllable airflow modification device  110  may be located on the body portion  104  of the active winglet  100 . In another embodiment, the controllable airflow modification device  110  may be located on the angled portion  106  of the active winglet  100 . In yet another embodiment, the controllable airflow modification device  110  may be located on both the body portion  104  and the angled portion  106  of the active winglet  100 . Further, and by way of example only, in the embodiment shown in  FIG. 1 , the controllable airflow modification device  110  is shown located on the aft of the active winglet  100  (i.e., the back-side of the active winglet  100  in relation to the front of an aircraft). In this way, adjustment of the controllable airflow modification device  110  may change the angle of the control surface  112  in relation to the aft portion (body portion  104  or angled portion  106 ) of the active winglet  100  that the control surface  112  is located. Additionally, as shown in  FIG. 1 , the active winglet  100  may include two controllable airflow modification devices  110 ; however, more or less controllable airflow modification devices  110  are possible. 
     Further, as shown in  FIG. 1  by way of example only, the angled portion  106  is shown as a basic trapezoidal shape. However the angled portion  106  may be rectangular, triangular, oval, or any other geometric shape. Additionally, the airflow control surface  112  located on the angled portion  106 , may be similar in shape to, or the same shape as, the airflow control surface  112  located on the body portion  104  of the active winglet  100 . 
     Additionally, the active winglet  100  in  FIG. 1  illustrates, by way of example and not limitation, a sensor  114  located in the center of the body portion  104  on the active winglet  100 . However, the sensor  114  may be located anywhere on the active winglet  100 , for example it may be located on the angled portion  106 , on the front of the body portion  104  (in relation to the aircraft), on the aft of the body portion  104  (in relation to the aircraft), on the surface of the winglet  100 , inside the winglet  100  (i.e., located within the surface of the winglet  100 ), anywhere within the entire aircraft, or the like. 
     Also depicted in  FIG. 1 , by way of example only, is an illustrative wing  102  of an aircraft (not shown) prior to the attachment of an active winglet  100  as described above. The wing  102  may include an aileron  116  and a flap  118 . The aileron  116  and the flap  118  are used for flight control of the aircraft and in some instances may be controlled by one or more pilots of the aircraft. 
       FIG. 1  also depicts the illustrative modified wing  120  which may include the illustrative wing  102  coupled to the active winglet  100 . The modified wing  120  may be designed and crafted for a new aircraft, or the active winglet  100  may be attached to the existing wing  102 . The active winglet  100  of modified wing  120  may be configured in a similar shape as the existing wing  102 . Additionally, and by way of example only, the winglet  100  may fit over a portion of the existing wing  102  such that the end of the existing wing  102  resides within the attachable portion  108  of the active winglet  100 . In other embodiments, however, the active winglet  100  may be attached to the existing wing  102  by fastening the end of the existing wing  102  to the attachable portion  108 . Further, the winglet  100  may be fabricated of the same or similar material as the existing wing  102 . 
     Illustrative Aircraft with Active Winglet 
       FIG. 2  depicts an illustrative load alleviation system  200  implemented on an aircraft  202  that includes at least one attached active winglet  100 . The components of the load alleviation system  200  may include sensors  114 , active winglet(s)  100 , a control system  204 , and control surface(s)  112 . By way of example only, and not limitation,  FIG. 2  illustrates one active winglet  100  on each wing of the aircraft  202 . However, active winglets  100  may also be placed on other surfaces of the aircraft  202 . For example, the active winglets  100  may be located on the wings, as shown, or they may be located on the tail wings, or any other horizontal or vertical surface of the aircraft  202 . 
     As mentioned above, the load alleviation system may comprise a control system  204 . The control system  202  may be configured to control the active winglets  100  of the aircraft  202 . By way of example only, and not limitation, the control system  204  may include one or more processor(s)  206  for receiving and processing system data, including, but not limited to, in-flight load factor data. In one embodiment, the processor(s)  206  may receive in-flight data from the sensors  114 . As mentioned above with respect to  FIG. 1 , although the sensors  114  are shown on the wing they may be located anywhere on the aircraft. The control system  204  may additionally consist of memory  208  for the storage of in-flight load factor data. The data stored in the memory  208  may include previously received load factor data, currently recorded (i.e., current in-flight) load factor data, or a compilation of current in-flight data and/or previously recorded in-flight data. By way of example only, the memory  208  of the control system  204  may include an operating system  210  and control logic  212 . 
     The operating system  210  may be responsible operating the control system  204  by way of interfacing the data with the processor(s)  206  and providing a graphical user interface (not shown) for interaction with one or more pilots of the aircraft  202 . The control logic  212  of the control system  204  may be configured to operate the control surface(s)  112  of the controllable airflow modification devices  110  of the active winglet  100 . In one embodiment, the control logic  212  may control the control surface(s)  112  based on in-flight load factor data received from the sensor(s)  114 . Additionally, although not shown here, predetermined parameters may be stored in the memory  206 . The predetermined parameters may also be used by the control logic  212  to determine operation of the control surface(s)  112 . In some embodiments, the control system  204  may operate each control surface  112  simultaneously or independently. By way of example only, the control system  204  of  FIG. 2  is illustrated in the hull of the aircraft  202 ; however, it can be located anywhere on the aircraft, including, but not limited to, the cockpit, the tail, the wing, or the like. 
     Illustrative Airflow Modification Devices 
       FIG. 3  depicts the active winglet  100  of  FIGS. 1 and 2  and includes a cross-sectional view  300  of the active winglet  100 , taken along line A-A. The cross-section  300  runs across the body portion  104  of the winglet  100 . Additionally, the cross-section  300  of the body portion  104  of the winglet  100  illustrates one embodiment of the components of the control system  204  of  FIG. 2  located in the active winglet  100 . As shown in  FIG. 3 , the control system  204  may be located in the body portion  104  of the winglet  100 ; however, the control system  204  may be located in the angled portion  106  of  FIG. 1  of the winglet  100 , in other portions of the active winglet  100 , or in any location on the aircraft. 
     In one embodiment, by way of example only, the control system  204  may be communicatively and/or mechanically coupled to the control surface  112  by way of a connection  302 .  FIG. 3  illustrates the connection  302  as one substantially straight coupling from the control system  204  to the control surface  112 . However, the connection  302  may bend, turn, pivot, or be a series of multiple connections to make the connection  304 . The connection  304  between the control system  202  and the control surface  112  may be operable by electronic, mechanic, or any other resource for coupling the control surface  112  to the control system  204 . The control surface  112  may be coupled to the active winglet  100  by a hinge, pivot, or other swivel device  304  to allow the control surface  112  to rotate the aft end up and/or down in relation to the body of the active winglet  100 . As noted above, to the commands given by the control system  204  to operate the control surface  112  of the active winglet may be based on the load factor data received by the control system  204  from the sensors  114  on the aircraft  202 . 
       FIG. 4  illustrates one embodiment  400  of the control system  204  as seen through the cross-section  300  of active winglet  100 . As discussed with reference to  FIGS. 2 and 3 , the control system  204  may control the control surface  112  of the active winglet  100  based on in-flight load factor data. The control system  204  may be coupled to the control surface  112  which may be illustrative of the airflow modification device  110  illustrated in  FIG. 1 . The control surface  112  may be coupled to the active winglet  100  by a hinge, pivot, or other swivel device  304  to allow the control surface  112  to move in relation to the commands given by the control system  204 . 
     Additionally, by way of example only,  FIG. 4  depicts an illustrative embodiment of a mechanical control system  402 . The mechanical control system  402  may include of a bob weight  404  coupled to a spring  406 . The bob weight  404  may be fabricated of lead, or any other weight which may activate the mechanical control system  402 . The spring  406  may be made of coil springs, bow springs, or any other device used to create resistance for the bob weight  404 . In one embodiment, and by way of example only, the bob weight  404  may be coupled to the control surface  112  by way of a coupling system  408 . By way of example only, coupling system  408  may be a rigid object, belt, chain, or other resource for coupling the bob weight  404  to the control surface  112 . The coupling system  408  is illustrated by way of example only, with two pivot points  410  and  412 , and one fixed point  414 . The coupling system  408  may also contain a series of pivot points, angles, or other connections. The coupling system  408  may be configured to connect to spring  406  at the fixed point  414 . 
     In one embodiment, the mechanical system  402  may be configured to react to in-flight conditions, for example, a gust of wind, maneuvers produced by one or more pilots, or any other condition on the wing of the aircraft. Based on the in-flight conditions, the bob weight  404  may change position within the mechanical system  402  relative to the spring. For example, the bob weight  404  may drop, lift, or otherwise change location, depending on the in-flight conditions. When the bob weight  404  changes location, it may cause the coupling system  408  to initiate a resistance force on the spring  406  causing a counter weight  416  to move in the opposite direction. Consequently, motion of the counter weight  416  may adjust the two pivot points  410  and  412  such that the coupling system  408  causes the connection  306  to adjust the control surface  112 . 
       FIG. 5  illustrates an additional embodiment  500  of a logical controller  502  as seen through the cross-section  300  of active winglet  100 . As discussed with reference to  FIGS. 2-4 , the logical controller  502 , much like the control system  204  of  FIG. 4 , may control the control surface  112  of the active winglet  100  based on in-flight load factor data. By way of example, and not limitation, the embodiment  500  of  FIG. 5  may include one or more sensors  114 , a logical controller  502 , and a motor  504 . The sensors  114  may be representative of the sensors illustrated in  FIG. 1 . The sensors  114  may be electronically coupled to the logical controller  502 . The logic controller  502  may be coupled to the motor  504 . The motor  504 , by way of example only, may be an electric motor. In one example, the motor  504  may be coupled to the control surface  112 . The motor  504  may be able to rotate the aft portion of the control surface  112  up or down, depending on the received in-flight conditions and the predetermined load factors programmed into the logical controller  502 . Additionally, the motor  504  may be coupled to the control surface  112  by way of electronic, pneumatic, hydraulic, or another resource for actuating the control surface  112 . In at least one embodiment, and by way of example only, the motor  504  may cause the control surface  112  to pivot on an axis, moving the aft portion up and or down to adjust the control surface  112  as calculated by the logical controller  502 . 
     The logical controller  502  may be located in the active winglet  100 , the cockpit (not shown), the main fuselage of the aircraft (not shown), or anywhere located on the aircraft. In-flight load factor data may be first received by the sensors  114  located on the aircraft  202 . The information may be resulting from deliberate in-flight maneuvers by a pilot, gusts of wind, or other causes of change in conditions to the aircraft. Information gathered by the sensors  114  may be received by the logical controller  502  and the data may be analyzed or otherwise processed. In one example, the logical controller  502  may be programmed with predetermined load factors which may be representative of a specific make and model of the aircraft. Additionally, the logical controller  502  may calculate the position of the control surface  112  based on the in-flight conditions to minimize the moment load on the wing. In other words, the logical controller  502  may receive the in-flight conditions and determine the needed position of the control surface  112 . Additionally, the logic controller  502 , may send a signal to the motor  504  to which it may be coupled to effectuate control of the control surface  112 . By way of example only, the motor  504  may be electronic, pneumatic, hydraulic, or any other type of motor. 
     Illustrative Comparison Graphs 
       FIG. 6  illustrates a graph  600  which compares the load factor on a wing of an aircraft in relation to the location on the wing of the aircraft. The wing of  FIG. 6  is a general representation of a wing and is not made representative of a specific make or model of an aircraft wing. The X-axis of the graph is illustrative of the location on the wing. It is represented in percentage (%) of the semi-span of the wing. The length of the wing is only a representation and is not limiting of the size of the wing on which an active winglet  100  may be installed. The Y-axis is representative of the lift distribution on the wing. The load is higher the closer to the center of the airplane. The graph  600  is for illustrative purposes only, and illustrates one example of the load distribution which an aircraft may experience. The graph  600  is not restrictive of whether or not the distributed load may be more or less at any point on the graph. The graph  600  is representative of the basic shape of the distributed load a wing may encounter. 
     The graph  600  illustrates the lift distribution on a traditional manufactured wing, which is represented by the line on the graph  600  with a dash and two dots. The graph  600  also illustrates the lift distribution on the wing when a traditional winglet is installed, which is represented by the dashed line. Additionally, the graph  600  illustrates the lift distribution on the wing when an active winglet  100  is incorporated on the wing. The comparison illustrates that the lift distribution caused by the traditional winglet may be greater at the wingtip. This may move the center of lift of the wing outboard which may increase the wing bending loads. However, when the wing has an active winglet  100  utilizing the load alleviation active winglet system  200  the lift distribution at the wing tip may drop significantly lower than that of a traditional winglet. The graph  600  illustrates that the load may even drop below zero at the location of the wing tip (the point furthest away from the aircraft). These loads are representative of the design load on the aircraft, which is the highest load an aircraft may see. When the active winglet controllable surfaces  112  are undeployed, the active winglet  100  produces the same efficiency benefits of a passive or fixed winglet. When the load factor increases and the loads on the wing increase, the control surfaces  112  on the winglet  100  may adjust to reduce the loads on the wing. In one embodiment, the active winglet control surfaces  112  may be undeployed or undeflected the majority of the time. However, in another embodiment, they may only be deployed when the load on the wing approaches the original design loads. 
       FIG. 7  illustrates a graph  700  representing a wing design stress comparison of active winglet systems, a wing with a winglet with no active system, and a standard wing. The design stress or design load is the critical load to which the wing structure is designed to carry. The X-axis represents the location along the length of an aircraft&#39;s wing. The unit is shown in percentage (%) of wing semi-span. The length of the wing is only a representation and is not limiting of the size of the wing on which an active winglet  100  may be installed. Additionally, in  FIG. 7 , the Y-axis represents the load on the wing. This load is illustrative of the design root bending moment load. The comparison shows the standard load that the wing bears. The graph  700  is for illustrative purposes only and is not meant to be restrictive in any way. The root bending moment load may be greater or smaller for varying wing makes and models. The graph  700  also shows the load of a wing when a winglet is added with no active systems. The graph  700  additionally shows the loads on the wing when a winglet is added to the wing. 
     With the active winglet system  200  enabled on the winglet  100  the design moment loads may be lower than the design loads on the wing with a winglet with no active system. Additionally, with the active system  200  enabled on the winglet  100 , the moment loads may be lower than the loads on the wings with no winglets installed. Traditional winglets increase wing stress, as a function of load factor, and substantially reduce the fatigue life of the wing. The slope of the “stress per g” curve is normally linear and the addition of passive winglets increases the slope which reduces the expected life and calculated life of the wing. Active winglets reduce the slope of this curve so that it is the same or lower than the slope of the original curve. 
     Illustrative Methods 
       FIG. 8  illustrates a flow diagram of one method  800  of receiving data, calculating, and positioning the control surface. As discussed above the sensors receive data based on the flight conditions of the aircraft. The method may, but not necessarily, be implemented by using sensors  112  shown in  FIG. 1 . In this particular implementation, the method  800  begins at block  802  in which the method  900  receives data from the sensors located on the aircraft. At block  804  the signal is received and computed with pre-registered data programmed into the adjustable control device. The adjustable control device in block  804  sends a signal, based on the calculation, to block the control surface  806 . At block  806  the control surface receives the signal and may be adjusted up or down based on its hinge point, depending on the signal received from the adjustable control device. 
     CONCLUSION 
     Although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments.