Patent Publication Number: US-2022219806-A1

Title: Adaptive ducted fan propulsion system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Phase application claiming priority to PCT Application No. PCT/US20/50507, filed on Sep. 11, 2020 which claims the benefit of and priority from U.S. Provisional Patent Application Ser. No. 62/898,741, filed on Sep. 11, 2019, the contents of which are hereby fully incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to propulsion systems and, more particularly, to adaptive ducted fan propulsion systems for use with aircraft such as unmanned aerial vehicles. 
     BACKGROUND 
     An advanced air mobility (AAM) including unmanned aerial systems (UAS) or urban air mobility (UAM) or regional air mobility (RAM) or unmanned aerial vehicle (UAV) or drone is an aircraft without any human pilot or passengers. UAVs may be fully autonomous or may be controlled remotely, such as with a remotely piloted aircraft system (RPAS). Existing UAMs and UAVs often take the form of a cylinder comprising an axially integrated propeller which is driven by an electric or turbo-reactive engine. UAMs and UAVs may include additional propulsion components such as an electric ducted fan (EDF), a ducted fan (DF), or a double ducted fan (DDF) comprising a double air absorbing mouth directed toward the propeller. 
     Such known propulsion devices suffer from a number of disadvantages. 
     First, these propulsion devices limit the power achieved by absorbing the mass of air directed to the propeller as the power provided by these known propulsion devices is generally directly proportional to the mass of the processed air. 
     Second, in order to operate these known propulsion devices under conditions of low atmospheric pressure, it is necessary to increase the frequency of the propulsion system speed to process the required amount of air, which leads to an exponential decrease in system efficiency overall (kWh of energy consumed in the report with N-thrust). 
     Third, due to the fixed structure (i.e., the fan duct) used in known propulsion devices, the propulsion device is incapable of adapting to variable atmospheric conditions. 
     Fourth, in the case of known turbo-fan devices (e.g., as is used on the Boeing 737 aircraft, which features a propulsion device with a fixed structure), the turbo-fan device works inefficiently on takeoff and during ascent to cruise altitude (Liters of kerosene per N Thrust), resulting in increased fuel consumption. 
     Taken together, the foregoing disadvantages are believed to result in economic losses of approximately 10%-12% (especially in terms of an airplane). 
     Accordingly, a need exists for an improved propulsion system for aircraft that addresses the foregoing disadvantages. 
     SUMMARY 
     Embodiments of the present application are directed devices and methods that reduce the interdependence between the maximum absorption capacity of the air masses in the system relative to the propulsion system surfaces represented by the Bernoulli equation. 
     Embodiments of the present application are directed towards conceptual and constructive improvements of existing propulsion devices widely employed in aviation. Embodiments provide a device representing a cylindrical pipeline whose profile is described by an adapted aerodynamic airfoil. Embodiments provide for an improved propulsion system, termed an adaptive ducted fan (ADF), that addresses disadvantages with conventional propulsion systems. 
     Embodiments in accordance with the present disclosure provide an ADF comprising integrated cinematic deployment mechanisms leading to the structural optimization of the inlet nozzle to enlarge the section but also the absorption capacity of the air masses directed to the propeller of the system of propulsion. 
     Embodiments in accordance with the present disclosure provide an ADF that amplifies and improves upon the ability of conventional propulsion systems to increase the quantity of air masses processed by the system, while increasing the surface of the low pressure area. 
     Embodiments in accordance with the present disclosure provide an ADF that may be applied to various aircrafts such as AAMs and drones (UAM/UAV/RPAS). Embodiments in accordance with the present disclosure provide an ADF offering automated and fast performance by exercising the growth of the input section of the air masses to the propeller, considerably increasing the thrust provided by the propulsion device (including in embodiments by approximately 35%-40%), and reducing energy consumption, all while maintaining approximately the diameter and mass of a standard ducted fan. 
     Embodiments in accordance with the present disclosure provide an ADF comprising an automated system incorporated into the propulsion system structure. Depending on the required mode, embodiments provide an ADF that may be employed using only some of the constituent elements disclosed herein, such as by applying the present disclosure to the hollow cavity section of the fan duct. Embodiments provide an ADF that can be mounted or integrated on any type of aviation propulsion system. 
     Embodiments in accordance with the present disclosure provide an ADF comprising metals, polymers, rigid, elastic, and flexible composite materials in various proportions such as the following: 60% carbon fiber; 15% aluminum T6; 10% titanium; 5% magnesium; and 10% polymers. 
     Embodiments in accordance with the present disclosure provide an ADF comprising a set of structural elements, which, when actuated are grouped in a predefined form, are integral by essence. A system of rails and levers ensures the optimal cinematic movement (release/retraction) for the entry of movable elements into the hollow cavity section of the fan duct. The movement is ensured by motor/electric motors or hydraulic or pneumatic systems. The steering of the pivot process is ensured by an electronic computing and/or control device, through electrical cables, optical fiber, or wireless technology. 
     Embodiments in accordance with the present disclosure provide an ADF comprising aerodynamic structural elements  5  equipped with brackets, rail system  6 , motor/engine assembly  7 , transmission  8 , and an arbitrary fan  9 . 
     Embodiments of an ADF in accordance with the present disclosure can be mounted on any type of ducted fan, including those widely used in the urban air mobility and regional air mobility or drone industry (such as UAV/RPAS), regardless of the type of propulsion of the fan or fans or propeller or propellers. Embodiments of an ADF in accordance with the present disclosure comprise metals, polymers, rigid, elastic, and flexible composite materials in various proportions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional aspects of the disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided below. 
         FIG. 1  is a top closed perspective view of the ADF propulsion system in accordance with one embodiment. 
         FIG. 2  is a bottom closed perspective view of the ADF propulsion system of  FIG. 1 . 
         FIG. 3  is a top opened perspective view of the ADF propulsion system of  FIG. 1 . 
         FIG. 4  is a bottom opened perspective view of the ADF propulsion system of  FIG. 1 . 
         FIG. 5  is a bottom perspective view of the chevron body of the ADF propulsion system of  FIG. 1 . 
         FIG. 6  is a bottom view of the streamlining of the ADF propulsion system of  FIG. 1 . 
         FIG. 7  is a top closed perspective view of the nacelle cap of the ADF propulsion system of  FIG. 1 . 
         FIG. 8  is a top opened perspective view of the nacelle cap of the ADF propulsion system of  FIG. 1 . 
         FIG. 9  is a cross-section illustration of the closed paddles inside of the nacelle of the ADF propulsion system of  FIG. 1 . 
         FIG. 10  is a top perspective view of the internal tube of the nacelle of the ADF propulsion system of  FIG. 1  with closed paddles. 
         FIG. 11  is a top perspective view of the internal tube of the nacelle of the ADF propulsion system of  FIG. 1  with opened paddles. 
         FIG. 12  is a perspective side view of the internal tube of the ADF propulsion system of  FIG. 1  with the linear motion and cinematics parts. 
         FIG. 13  is a ¼ section of the internal tube of the ADF propulsion system of  FIG. 1  with a 1st round of cinematic parts. 
         FIG. 14  is a ¼ section of the internal tube of the ADF propulsion system of  FIG. 1  with a 2nd round of cinematic parts. 
         FIG. 15  is a ¼ section of the internal tube of the ADF propulsion system of  FIG. 1  with paddles and cinematic parts. 
         FIG. 16  is a ¼ section view of the internal tube of the ADF propulsion system of  FIG. 1  with the paddles attached to supports. 
         FIG. 17  is an enlarged view of the ADF propulsion system of  FIG. 1  showing a movable hood assembly of the hood areas of ADF and a control module. 
         FIG. 18  is a perspective view of the ADF propulsion system of  FIG. 1  showing the paddles  2  in a partially opened configuration. 
         FIG. 19  is an enlarged view of the ADF propulsion system of  FIG. 1  showing intermediate transmission elements between the support plate  6  and the paddles  2 . 
         FIG. 20  is a sectional view of the ADF propulsion system of  FIG. 19  depicting the directions of movement of the paddles  2  relative to the internal tube  1  indicated by arrows. 
         FIG. 21  is a sectional view of the ADF propulsion system of  FIG. 19  taken on the opposite side from that of  FIG. 20  depicting the directions of movement, as indicated by the arrows, of fulfilling the positive/negative tilt of the paddles  2  against the internal tube  1 . 
         FIGS. 22 a  and 22 b    are sectional views of the ADF propulsion system of  FIG. 1  taken through the kinematic elements  21 ,  22  shown in  FIG. 20 . 
         FIGS. 22 c  and 22 d    are sectional views of the ADF propulsion system of  FIG. 1  taken through the kinematic elements  21 ,  22  shown in  FIG. 21 . 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     Referring specifically to  FIGS. 1 and 2 , an adaptive ducted fan (ADF) propulsion system  100  (also referred to herein as an ADF or an ADF device) comprises an aerodynamic cave tube  102  (also referred as a nacelle) having a plurality of inner panels  1 , a plurality of caps  4 , a plurality of chevron panels  3  cooperative forming a chevron cover, and streamlining  5 . A propeller  37  rotates within the tube  102  proximate the inner panels  1 , causing air to flow through the tube  102 . 
     The ADF  100  features multiple phases. In  FIGS. 1 and 2 , the ADF  200  is depicted in a closed phase, wherein the caps  4  are proximate the chevron panels  3  (i.e., such that the tube  102  forms a hollow cylinder with the propeller  37  located in the center of the cylinder). 
     As depicted in  FIGS. 3 and 4 , the ADF propulsion system also has an open phase. As shown, the caps  4  are independently actuated and fold apart from the chevron panels  3  in the open phase, permitting a plurality of paddles  2  which are independently actuated to extend from the interior of the tube  102  (thereby changing the profile of the ADF  100 ). 
     As shown in  FIG. 5 , in an embodiment the tube  102  comprises two symmetrical chevron panels  3  having a rounded profile. This shape and configuration of chevron panels  3  ensures an optimal mixture of the air streams generated by propeller  37  and the air flow obtained from the atmosphere due to the Venturi effect when the ADF  100  is in the closed configuration. As a result, this configuration of chevron panels  3  in the closed configuration minimalizes air disturbances and the noise emitted by the ADF device  100 . In alternative embodiments, other configurations of chevron panels  3  may be utilized, as will be clear to one of skill in the relevant art, such as forming the chevron cover from a single chevron panel  3  or more than two chevron panels  3 . 
       FIG. 6  depicts the streamlining  5  of the ADF device  100  with the other elements of the ADF  100  omitted for clarity. As shown, the streamlining comprises a plurality of blades  602  rotatably held within a housing  604 . The configuration of streamlining  5  forces air flowing through the tube  102  due to rotation of the propeller  37  to move in a spiral. The blades  402  have a radial arrangement and an involute aerodynamic profile along their inner surface, which directs the air flow along the rotor axis of the propeller  37  (thereby increasing the processed air pressure through the ADF  100 ). 
       FIGS. 7 and 8  depict the caps  4  of the ADF  100  with the other elements of the ADF  100  omitted for clarity. The caps  4  function to ensure the aerodynamic integrity of the nacelle  102  while in a closed phase, as depicted in  FIG. 7 . In the closed phase, the caps  4  cover the interior of the tube  102  and provide a smooth surface for air to travel along. 
     In the opened phase depicted in  FIG. 8 , the caps  4  are actuated apart such that the caps  4  are separate from one another and the chevron panels  3 , providing access to the interior of the tube  100  and allowing the paddles  2  to extend proximate the inner panels  1 . 
       FIG. 9  depicts a cross-sectional view of the ADF device  100  shown in  FIG. 1  in its closed phase, which allows for viewing the arrangement of the component parts. As shown, in the closed phase paddles  2  are folded into the hollow walls of the tube  102  and are fully covered by caps  4 , chevron  3 , and inner panels  1 . 
       FIG. 10  depicts the ADF  100  of  FIG. 1  with the chevron panels  3  and caps  4  omitted, so as to better illustrate the compact arrangement of the paddles  2  and the support plates  6  around the inner panels  1  of the tube  102  in the closed phase. As shown, each paddle  2  is rotatably mounted to a support plate  6 . Each support plate  6  is slidably mounted to the interior side of an inner panel  1 . 
     In the embodiment shown, there are an even number (i.e, eight) of paddles  2  and in the closed phase, the panels  2  are arranged equidistant from, and overlapping, one another. In alternative embodiments, other configurations of paddles  2  may be used as will be clear to one of skill in the art from the present disclosure. 
       FIG. 11  depicts the ADF  100  of  FIG. 1  with the chevron panels  3  and caps  4  omitted, so as to better illustrate the compact arrangement of the paddles  2  in the open phase. As shown, the paddles  2  move proximate the top edges of the inner panels  1  while in the open phase, thereby forming an inlet diffuser which increases the air section/air area about the mouth of the tube  102  by about 2.3 times and/or Ø 53% relative to the section passage of air into the propeller area  37  in the closed phase. As shown, the panels  2  abut one another and have substantially no space in between one another in the open phase. The panels  2  are curved away from the central axis of the tube, such that the radius of the opening of the tube  102  at the front end of the panels  2  is larger than the radius of the tube  102  at the bottom end of the panels  2 . 
       FIG. 12  depicts the ADF  100  of  FIG. 1  with the chevron panels  3 , caps  4 , and panels  2  omitted to better depict the structure of the outer wall of the inner panels  1 . The inner panels  1  collectively form the inner wall of the tube  102  and serve as mounting/positioning base supports for the other components of the ADF device  100 . As shown, each supporting plate  6  moves along three servo-linear directions  18  (also termed an actuator), each of which is threaded. Each supporting plate  6  is configured to hold two adjacent panels  2  (not show). For each panel  102 , a kinematic guiding plate  21 ,  22  is located against the outer surface  1202  of inner panel  1 . The servo-linear directions  18  are equipped with position sensors (encoders)  38  and are held to the outer surface  1202  of the inner panels  1  by gripping elements  24 . Supporting plates  6  are mounted with three-point fastening through the threads of the servo-linear directions  18 . By rotating the servo-linear directions  18 , the supporting plates  6  may be raised or lowered. 
       FIG. 13  depicts one fourth (i.e., the connection points and associated mechanisms for two of the eight panels  2 ) of the ADF  100  of  FIG. 1  with the chevron panels  3 , caps  4 , and panels  2  omitted to better depict the structure of the outer wall of the inner panels  1 . 
       FIG. 14  depicts an enlarged view of  FIG. 13  showing the components joining the panels  2  to the supporting plats  5 . As shown, a support plate  6  is connected to an angle bracket  17 . The support plate  6  and angle bracket  17  may be joined by screws, bolts, or other suitable connectors. A joint  39  is connected to the vertical protrusion of angle bracket  17 . The joint  39  may be screwed into an opening on the angle bracket  17  as shown or connected via another suitable mechanism. The joint  39  is screwed to components  10 ,  11 , and  13  to form a resistance frame. The component  11  is secured by rotation through the plate  19  screwed onto the component  13 . On the component  11  is rigidly mounted the type A lever  16 , on which extremities a bearing is attached by special screws  7 ,  15 . The component  13  engages the hinge  39 , the hinge  10  is secured to the hinge  39  which engages another articulation  39 , forming the second frame of resistance. In this frame of resistance, on the rod  10  there are rigidly fixed two type A brackets  8 . 
       FIG. 15  depicts another enlarged view of  FIG. 13 . As shown, lever  14  is mounted to, rod  11 . Bearings  25  are clamped to the lever  14  by means of specialized screws  7 ,  15 . The lever  14  is further operatively connected to support  9  by means of a pair of articulations  39  that are operatively connected by threaded plate  20 . 
       FIG. 16  depicts the one quarter view of  FIG. 13  with the paddles  2  attached to supports  9 . As shown, thee supports  9  comprise type A fasteners  8 . 
     With reference to  FIG. 17  (which depicts the ADF  100  with the chevron panels  3  omitted to better illustrate the interior of the ADF  100 ), in an embodiment the ADF  100  provides a propulsion system that is adaptable during use. In an embodiment shown, the ADF  100  comprises a control module  1702  configured to change the phase of the ADF (i.e., from the open phase to the closed phase, and vice versa). The control module  1702  determines when a change in phase is desirable. Such determination may be done automatically or using input from a pilot of the aircraft to which the ADF device  100  is mounted. The control module  1702  is linked by connections  1704  to the servo-linear directors  18  and the encoders  39 . The connections  1704  may be wired, wireless, or any other form of connection that permits the exchange of information and commands. 
     To change phase, the control module  1702  issues a command to the servo-linear directors  18  (whose position is controlled by the encoders  39 ) to rotate. As a result, the support plate  6  moves along with the associated mounted components  2 ,  7 ,  8 ,  9 ,  10 ,  11 ,  13 ,  14 ,  15 ,  16 ,  17 ,  19 ,  20 ,  25 ,  39 , at the same time opening the caps  4 . In addition to the open and closed phases shown in  FIGS. 1 and 3 , respectively, the ADF device  100  may move to a partially opened phase such as that shown in  FIG. 18 , which depicts the kinematic of two different groups by positioning the paddles  2 . As will be clear to one of skill in the art, any number of partially opened phases may be used to provide fine-tuned control over the ADF  100 . 
       FIG. 19  depicts an enlarged view of the intermediate transmission elements between the support plate  6  and the paddles  2  according to  FIG. 18 . 
       FIG. 20  depicts a sectional view of the mechanisms of  FIG. 19  with the directions of movement of the paddles  2  towards the internal tube  1  indicated by arrows. As shown, radial ball bearings  2002  rotate and permit movement of the support plate  6  along the inner panel  1 . 
     Similarly,  FIG. 21  depicts a sectional view of the mechanisms of  FIG. 19  with the directions indicated by the arrows fulfilling the positive/negative tilt of the paddles  2  against the internal tube  1 . Arrows depict the movement of the panels  2 , support plate  6 , and rotation about component  11 . 
       FIGS. 22 a  and 22 b    depict sectional views of the kinematic elements  21 ,  22  shown in  FIG. 20  demonstrating the kinematic guidance process. Following the radial bearing interaction with the route for the bearing, the lever  16  moves, which is limited and articulated by the components entering it in the interaction with. The route for the bearing has a special profile and is endowed with extrusions with geometric latches designed to stop the radial bearings as described in this alignment. 
       FIGS. 22 c  and 22 d    depict sectional views of the kinematic elements  21 ,  22  shown in  FIG. 21  demonstrating the kinematic guidance process following the bearing interaction with the route for bearing, by moving the lever  14 , which is limited and articulated by the components entering it in the interaction. Route for bearing has a special profile and is endowed with extrusions with geometric latches designed to stop the radial bearings described in this alignment. 
     The movement of the pedals  2  is completed by aligning them with the top of the internal tube inlet diffuser  1 , forming the adaptive diffuser of the ADF device  100  shown in  FIGS. 3, 4, 11, 16 . 
     To return to the closed phase, the previously described movements are repeated in reversed order, beginning with the command issued by the module control  1702  and finishing with the caps  4  closing. 
     As will be clear from the foregoing disclosure, in an embodiment, the ADF propulsion system comprises a cavity tube  102  that serves a resistance and support structure for all components of the ADF  100 . The tube  102  is a revolving surface of an aerodynamic profile on the inside  1204 , and outside  502  is an extruded surface representing several planar surfaces where the ADF component details are mounted. The tube design is scalable and modular, permitting ready adaptation to height and diametric adjustments. It is important that the outer tube/mounting surface  502  is individual and can be made as an independent module that can be scaled and easily adapted to any known ducted fans. The tube  102  is made of lightweight composites, polymers, and metals. 
     In order to ensure aerodynamic integrity, there is provided a chevron cover formed from chevron panels  3  that covers the internal structure of the ADF device  100  and also serves to minimize the aerodynamic drag. The “jagged” design of the lower edges  504  of the chevron panels  3  is an individual sinusoid with an even number (as shown, eight) elongated sinusoidal shapes that provide an optimal blend of airflow while maintaining a minimal of 60 dB noise at sub-sonic speeds. It is to be mentioned that the structure, shape, and arrangement of this “jagged” design of lower edges  504  make it possible for the noise emitted by the entire ADF  100  to be emitted with a delay of about one second. The cover chevron  3  is made of lightweight composites and malleable deformable alloys. 
     In order for the ADF system  100  to be adaptable, it includes movable caps  4  of a convex shape, which upon closure ensure aerodynamic integrity and, when opened, ensure that the paddles  2  are moved outwards. The movable caps  4  are made of lightweight composites and malleable deformable alloys. 
     To provide a high pressure jet from the ADF device  100 , a series of aerodynamically curved blades  602  are individually created and radially positioned about the geometric center of the ADF device  100 , a process referred to as streamlining construction, which resulted from the controlled increase/decrease in the volume of processed air by the ADF  100 . The curved blades  602  are made of lightweight composite materials and malleable deformable alloys. 
     In an embodiment, the ADF device  100  has two working phases: (i) Work Phase A (or the closed phase), which is the geometric form of a conventional ducted fan with the addition of a chevron cover as described herein and (ii) Work Phase B (or the opened phase), in which an even number of paddles along with other secondary mechanisms are adjusted to ensure the increase of the air mass, which may be approximately processed twice. 
     The even number of paddles  2  whose shape is a curved aerodynamic profile at ¾ of its rope is revolved at 45° to obtain a light and rigid cavity body with an optimal number of fasteners to not overburden the mass of the ADF device  100 , which provides substantial advantages over prior designs by making the propulsion system adaptable and more efficient. The paddles  2  are made of light composite materials and malleable deformable alloys. 
     The paddles  2  are arranged side by side at their openings. When in Phase B, the paddles  2  form a diffuser inlet that accelerates the air masses to the propeller  37 . When closed in Phase A, the paddles  2  take an overlapping array arrangement. The opening/closing process is performed in an automatic cycling mode which in an embodiment lasts for about three seconds. 
     There are two groups of paddles  2  in the closed phase. A first group  1002  of paddles  2  is located directly adjacent to the internal tube  1  and another group  1004  of paddles  2  is in the immediate proximity of the paddles group  1002 , occupying the minimum space of arrangement. 
     In an embodiment, two types of individual kinematic guide plates  21 ,  22  are used that differ only through the profile of their respective tracks, and made up depressions. These guide plates  21 ,  22  may be arranged in an alternating arrangement such that no guide plate  21 ,  22  is adjacent to a guide plate  21 ,  22  of the same profile. The geometry of the guide plates  21 ,  22  is individually tailored according to the assigned mechanical requirements of the paddles  2  during their transition from Phase A to B and vice versa. The guide plates  21 ,  22  are made of polymers, composites, and metals. 
     A concentric disk-section segment of the inner tube  1  repeats the radius of the internal tube  1 ; it has two plane surfaces with threaded joints that support the mass and physical loads of the kinematic momentum and 70% of the elements that describe it. The board is made of slightly malleable light alloys, polymers, and composite material. 
     Each of these embodiments and obvious variations thereof are contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims. Moreover, the present concepts expressly include any and all combinations and sub-combinations of the preceding elements and aspects. The present disclosure is not limited to the specific illustrated example but extends to alternative embodiments, other shapes and/or configurations in accordance with the knowledge of one of ordinary skill in the art applied consistent with the presently disclosed principles.