Patent Publication Number: US-11639236-B2

Title: Apparatus and method for launching a fixed-wing aircraft into free flight

Description:
PRIORITY CLAIM 
     This continuation application claims priority to and the benefit of U.S. patent application Ser. No. 16/119,301, filed on Aug. 31, 2018 which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/554,901, which was filed on Sep. 6, 2017, and U.S. Provisional Patent Application No. 62/657,104, which was filed on Apr. 13, 2018, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure generally relates to systems and methods for launching fixed-wing aircraft into free, wing-borne flight and for retrieving fixed-wing aircraft from free, wing-borne flight. More specifically, the present disclosure relates to systems and methods for launching fixed-wing aircraft into free, wing-borne flight using a parasail and for retrieving fixed-wing aircraft from free, wing-borne flight using a parasail. 
     BACKGROUND 
     Aircraft capable of long-distance, efficient cruising flight typically require long runways for take-off and landing. This limits the locations from which the aircraft can take-off and at which the aircraft can land, since many locations—such as ships at sea—don&#39;t have sufficient space for a runway. Hovering aircraft are also proposed for use where space is limited. However, hovering aircraft tend to be more wind susceptible and the relatively large spinning blades that hovering aircraft typically employ make them unwelcome on small ship decks. There is a need for new systems and methods that eliminate the need for these aircraft to use long runways to take-off and land. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIGS.  1 A- 1 D  are diagrammatic views showing one example parasail-assisted method of launching a fixed-wing aircraft into free, wing-borne flight using an aircraft launch system including two winches. 
         FIGS.  2 A- 2 D  are diagrammatic views showing one example parasail-assisted method of retrieving a fixed-wing aircraft from free, wing-borne flight using an aircraft retrieval system including two winches. 
         FIG.  3 A  is a perspective view of one example embodiment of the aircraft-launch apparatus of the present disclosure attached to a fixed-wing aircraft. 
         FIG.  3 B  is a top plan view of the aircraft-launch apparatus and the fixed-wing aircraft of  FIG.  3 A . 
         FIG.  3 C  is a partially-exploded perspective view of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 D  is a block diagram showing certain electrically-controlled components of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 E  is a perspective view of the hub module of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 F  is a partially exploded perspective view of the hub base of the hub module of  FIG.  3 E . 
         FIG.  3 G  is a partially exploded perspective view of one of the female blind mate assemblies of the hub base of  FIG.  3 F . 
         FIG.  3 H  is a partial cross-sectional view of one of the flexural mounts of the female blind mate assembly of  FIG.  3 G . 
         FIG.  3 I  is a perspective view of the fixed-wing aircraft of  FIG.  3 A  attached to the saddle of the hub module of  FIG.  3 E . 
         FIG.  3 J  is top perspective view of the saddle of  FIG.  3 I . 
         FIG.  3 K  is a cross-sectional view of the saddle of  FIG.  3 I  taken substantially along line  4 C- 4 C of  FIG.  3 J  and with certain elements removed. 
         FIGS.  3 L and  3 M  are, respectively, assembled and exploded top perspective views of a rear engager of the saddle of  FIG.  3 I . 
         FIG.  3 N  is an exploded top perspective view of the attachment/release device of the part of the saddle of  FIG.  3 I . 
         FIGS.  3 O- 3 Q  are cross-sectional side elevational views of the part of the saddle of  FIG.  3 I  showing different configurations of the lock arm and the front engager arm taken substantially along the line  4 G- 4 G of  FIG.  3 J . 
         FIG.  3 R  is a perspective view of one of the arm modules of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 S  is perspective view of the locking assembly of the arm module of  FIG.  3 R . 
         FIGS.  3 T,  3 U, and  3 V  are side elevational views of the arm module of  FIG.  3 R  detaching from the hub module of  FIG.  3 E  via the locking assembly of  FIG.  3 S . 
         FIG.  3 W  is a perspective view of one of the front landing gear modules of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 X  is a perspective view of one of the rear landing gear modules of the aircraft-launch apparatus of  FIG.  3 A . 
         FIG.  3 Y  is a perspective view of an example aircraft-launch apparatus and hoisting device. 
         FIG.  3 Z  is an enlarged perspective view of the aircraft-launch apparatus of  FIG.  3 Y . 
         FIG.  3 AA  is a perspective view of the launch apparatus of  FIGS.  3 Y and  3 Z  having an aircraft coupled via a release mechanism. 
         FIG.  3 BB  is perspective views of a launch cradle in an operating position and a stowed position, showing how the launch cradle may be pivotably mounted to a parasail mast, to maintain azimuth alignment of the launch cradle and the hoisting device. 
         FIGS.  3 CC and  3 DD  are perspective views of a release mechanism according to certain embodiments of the present disclosure. 
         FIGS.  4 A- 4 E  are diagrammatic views showing another example parasail-assisted method of launching a fixed-wing aircraft into free, wing-borne flight using an aircraft launch system including a single winch. 
         FIGS.  5 A- 5 E  are diagrammatic views showing another example parasail-assisted method of retrieving a fixed-wing aircraft from free, wing-borne flight using an aircraft retrieval system including a single winch. 
         FIGS.  6 A- 6 C  are diagrammatic views showing another example parasail-assisted method of launching a fixed-wing aircraft into free, wing-borne flight using an aircraft launch system including a winch and a hoist, wherein the hoist is supported by the parasail tow line. 
         FIGS.  6 D- 6 G  are diagrammatic views showing another example parasail-assisted method of retrieving a fixed-wing aircraft from free, wing-borne flight using an aircraft launch system including a winch and a hoist, wherein the hoist is supported by the parasail tow line. 
         FIGS.  7 A and  7 B  are diagrammatic views showing the spatial relationship between a hoist and parasail of various example embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     While the features, methods, devices, and systems described herein may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments. Not all of the depicted components described in this disclosure may be required, however, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the arrangement and type of the components; the shapes, sizes, and materials of the components; and the manners of attachment and connections of the components may be made without departing from the spirit or scope of the claims as set forth herein. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the disclosure as taught herein and understood by one of ordinary skill in the art. The drawings are not to scale unless noted otherwise. 
     The parasail-assisted fixed-wing aircraft launch and retrieval systems (sometimes called the “launch system(s)” and the “retrieval system(s)” for brevity) of various embodiments of the present disclosure are usable to launch a fixed-wing aircraft  30  from a moving object into free, wing-borne flight and to retrieve the fixed-wing aircraft  30  from free, wing-borne flight back onto the moving object. The fixed-wing aircraft  30  may be any suitable fixed-wing aircraft, such as (but not limited to) the INTEGRATOR unmanned aerial vehicle (INTEGRATOR is a registered trademark of Insitu, Inc.), the SCANEAGLE unmanned aerial vehicle (SCANEAGLE is a registered trademark of the Boeing Company), or X400 (X400 is a registered trademark of Insitu, Inc.). The moving object is a ship in the example embodiments described below, but may be any other suitable moving object in other embodiments (such as a truck or a railcar). 
     1. Two-Winch Embodiment 
     1.1 Parasail-Assisted Fixed-Wing Aircraft Launch System and Method 
       FIGS.  1 A- 1 D  are diagrammatic views showing one example parasail-assisted fixed-wing aircraft launch system and method of the present disclosure. In this example embodiment, the aircraft launch system includes a parasail P, a ballast B, a fixed-wing aircraft-launch apparatus  10  (sometimes called the “aircraft-launch apparatus” for brevity), a first winch  1110 , a first flexible member  1110   a , a first flexible member attachment device  1112 , a pulley  1114 , a second winch  1120 , and a second flexible member  1120   a.    
     The parasail P may be any suitable parasail including a kite, left and right bridle sets attached to the kite, and suitable rigging connecting the left and right bridle sets to the first flexible member  1110   a  (described below). The parasail P is rated such that it is strong enough to carry the aircraft-launch apparatus  10  together with the fixed-wing aircraft  30  without breaking. 
     The ballast B may be any suitable container filled with any suitable material (such as water, rock, or sand), and is attached to the left and right bridle sets such that the mass of the ballast B is generally evenly distributed between the left and right bridle sets. The mass of the ballast B is large enough to stabilize the parasail P when the parasail P is flying. In this example embodiment, the mass of the ballast B is between 30-150 pounds, though it may have any other suitable mass required to stabilize the parasail P when open. 
     The first winch  1110  is any suitable reversible, non-backdriveable winch (though it may be any other suitable type of winch in other embodiments) that includes a shaft, a drum fixedly mounted to the shaft, and a motor operably connected to the shaft to rotate the shaft (and therefore the drum). In this example embodiment, the first winch  1110  is a 2-10 horsepower worm gear winch. The second winch  1120  is a suitable reversible, backdriveable winch (though it may be any other suitable type of winch in other embodiments) that includes a shaft, a drum fixedly mounted to the shaft, and a motor operably connected to the shaft to rotate the shaft (and therefore the drum). In this example embodiment, the second winch  1120  is a 1 horsepower winch backdriveable at 200 pounds of tension. As described below, the first and second winches  1110  and  1120  are independently controllable to payout and retract the first and second flexible members  1110   a  and  1120   a , respectively, as described below. 
     The first and second flexible members  1110   a  and  1120   a  are suitable ropes or other similar flexible elements. 
     The first flexible member attachment device  1112  is a suitable device configured to removably attach to the first flexible member  1110   a . In this example embodiment, the first flexible member attachment device  1112  is an ascender that, once attached to the first flexible member attachment device, can move along the first flexible member in one direction but not the other. In other embodiments, the first flexible member attachment device is not configured to move relative to the first flexible member once attached to the first flexible member. A rope grab is one example of such a device. 
     The pulley  1114  is attached to the first flexible member attachment device  1112  and includes a wheel (not labeled) rotatably mounted on a shaft (not labeled). The pulley  1114  may be configured as a one way pulley, which includes a suitable component or suitable components, that enable the wheel to rotate around the shaft in one rotational direction—here, counter-clockwise—and that prevent the wheel from rotating around the shaft in the other rotational direction—here, clockwise. 
       FIGS.  3 A,  3 B, and  3 C  show the aircraft-launch apparatus  10 . The aircraft-launch apparatus  10  is modular in that it is assembled from (and can be disassembled into) a plurality of different modules or subassemblies. The aircraft-launch apparatus  10  is removably attachable to the fixed-wing aircraft  30  to facilitate launching the fixed-wing aircraft  30  into free, wing-borne flight (as described below). 
     As best shown in  FIG.  3 C , the aircraft-launch apparatus  10  includes the following nine modules or subassemblies: a hub module  100 ; first, second, third, and fourth arm modules  400   a ,  400   b ,  400   c , and  400   d ; first and second front landing gear modules  600   a  and  600   b ; and first and second rear landing gear modules  600   c  and  600   d.    
     As described in detail below, to assemble the aircraft-launch apparatus  10  from these nine modules or subassemblies, an operator: (1) attaches the first, second, third, and fourth arm modules  400   a ,  400   b ,  400   c , and  400   d  to the hub module  100 ; (2) attaches the first and second front landing gear module  600   a  and  600   b  to the first and second arm modules  400   a  and  400   b , respectively; and (3) attaches the first and second rear landing gear modules  600   c  and  600   d  to the third and fourth arm modules  400   c  and  400   d , respectively. 
     The modularity of this aircraft-launch apparatus  10  is beneficial compared to non-modular or unitary construction. First, the modularity of this aircraft-launch apparatus  10  enables an operator to quickly and easily disassemble this relatively large apparatus into nine smaller modules or subassemblies. The operator can compactly store these modules or subassemblies into a single container, which makes the disassembled aircraft-launch apparatus  10  easy to store and transport compared to when it is assembled. Second, if a part of this aircraft-launch apparatus  10  breaks, its modularity enables the operator to quickly and easily replace the module(s) or subassembly(ies) including the broken part with a properly-functioning replacement module(s) or subassembly(ies) rather than waste time repairing the broken component(s). 
     Other embodiments of the aircraft-launch apparatus may include more or fewer modules. 
       FIG.  3 D  is a block diagram of certain electrically-controlled components of the aircraft-launch apparatus  10 . In this embodiment, although not shown in  FIG.  3 D , a lithium-ion battery (or any other suitable power source(s)) powers these components. For a given component, the power source may be directly electrically connected to that component to power that component or indirectly electrically connected to that component (e.g., via another component) to power that component. 
     The hub module  100  includes a hub base  200  and a saddle  300 . The hub base  200  includes a controller  272  and a communications interface  274  electrically and communicatively connected to the controller  272 . The saddle  300  includes a front engager servo motor  6341  and a lock servo motor  6345  both electrically and communicatively connected to the controller  272 . This is merely one example configuration, and these components may be located on any suitable part of the aircraft-launch apparatus in other embodiments. 
     The controller  272  includes a processor  272   a  and a memory  272   b . The processor  272   a  is configured to execute program code or instructions stored in the memory  272   b  to control operation of the aircraft-launch apparatus  10 , as described herein. The processor  272   a  may be one or more of: a general-purpose processor; a content-addressable memory; a digital-signal processor; an application-specific integrated circuit; a field-programmable gate array; any suitable programmable logic device, discrete gate, or transistor logic; discrete hardware components; and any other suitable processing device. 
     The memory  272   b  is configured to store, maintain, and provide data as needed to support the functionality of the aircraft-launch apparatus  10 . For instance, in various embodiments, the memory  272   b  stores program code or instructions executable by the processor  272   a  to control the aircraft-launch apparatus  10 . The memory  272   b  may be any suitable data storage device, such as one or more of: volatile memory (e.g., RAM, which can include non-volatile RAM, magnetic RAM, ferroelectric RAM, and any other suitable forms); non-volatile memory (e.g., disk memory, FLASH memory, EPROMs, EEPROMs, memristor-based non-volatile solid-state memory, etc.); unalterable memory (e.g., EPROMs); and read-only memory. 
     The communications interface  274  is a suitable wireless communication interface, such as a transceiver like an MM2 900 MHz Embedded Radio by Freewave Technologies, configured to establish and facilitate communication between the controller  272  and: (1) a computing device (such as a laptop computer, a tablet computer, or a mobile phone, not shown); and (2) an R/C controller (not shown) that the operator of the aircraft-launch apparatus  10  controls. In operation, once the communications interface  274  establishes communication with the computing device, the controller  272  can send data (via the communications interface  274 ) associated with the operation of the aircraft-launch apparatus  10  to the computing device. Once the communications interface  274  establishes communication with the R/C controller, the controller  272  can receive signals (via the communications interface  274 ) from the R/C controller. More specifically, upon receipt of these signals from the R/C controller, the communications interface  274  converts these signals into a format readable by the controller  272  and sends the converted signals to the controller  272  for processing. 
     The above-described communication may be bidirectional or unidirectional. In some embodiments, the communications interface  274  enables the controller  272  to send data to the computing device but not receive data from the computing device. In other embodiments, the communications interface  274  enables the controller  272  to send data to the computing device and to receive data from the computing device. In some embodiments, the communications interface  274  enables the controller  272  to receive signals from the R/C controller but not send signals to the R/C controller. In other embodiments, the communications interface  274  enables the controller  272  to receive signals from the R/C controller and send signals to the R/C controller. 
     In certain embodiments, the communications interface  274  includes separate components for communicating with the computing device (such as a telemetry link) and the R/C controller (such as an R/C receiver). 
       FIG.  3 E  shows the hub module  100 . The hub module  100 : (1) serves as the attachment point for the arm modules  400   a  to  400   d ; (2) is the portion of the aircraft-launch apparatus  10  to which the fixed-wing aircraft  30  is attached for launch; (3) includes the power source for the aircraft-launch apparatus  10 ; and (4) includes certain components used to control operation of the aircraft-launch apparatus  10 . 
     The hub module  100  includes a hub base  200  and a saddle  300 . The saddle  300  is attached to the underside of the hub base  200  via various brackets and fasteners (not labeled). This is merely one example of how the saddle can be attached to the hub base, and in other embodiments the saddle may be attached to the hub base in any suitable manner. 
       FIGS.  3 F,  3 G, and  3 H  show the hub base  200  or components thereof. The hub base  200  is the portion of the hub module  100  that: (1) serves as the attachment point for the arm modules  400   a  to  400   d ; (2) includes the power source for the aircraft-launch apparatus  10 ; and (3) includes certain components used to control operation of the aircraft-launch apparatus  10 . 
     As best shown in  FIG.  3 F , the hub base  200  includes four elongated tubular rectangular supports  210   a ,  210   b ,  210   c , and  210   d  attached to a first mounting plate  202  with suitable brackets and fasteners. Stabilizing brackets (not labeled) extend between and connect the free ends of the supports  210   a  and  210   b  and the supports  210   c  and  210   d . A second mounting plate  250   b  is attached to the supports  210   a ,  210   b ,  210   c , and  210   d  such that the supports are sandwiched between the first and second mounting plates  202  and  250 . A housing  270  is mounted to the second mounting plate  250 . The housing  270  encloses various electrical components, such as the power source, the controller  272 , and the communications interface  274 . 
     A guard  282  is attached to a guard mounting bracket  280  (via suitable fasteners) that is attached to the second mounting plate  250  (via suitable fasteners). A snag-prevention member attachment device  284  is attached to the guard  282  near the center of the guard  282  (when viewed from the top). As described in detail below, a snag-prevention member  299  is attachable to the snag-prevention member attachment device  284  (such as a universal joint) such that the snag-prevention member  299  can rotate 360 degrees (or less in other embodiments) relative to the guard  282  and the aircraft-launch apparatus  10  and pivot relative to a vertical axis between an angle defined by the geometry of the guard  282  and the geometry of the snag-prevention member  299 . In this embodiment, the snag-prevention member  299  includes a flexible rod (such as a carbon-fiber rod) that has a normal shape to which it is biased to return once flexed. The snag-prevention member  299  may attach to the snag-prevention member attachment device  284  in any suitable manner, such as via a carabiner or other hook-type manner of attachment. 
     The open free ends of the tubular supports  210   a - 210   d  form arm module receiving sockets that can receive one of the arm modules  400   a  to  400   d . Specifically, the support  210   a  forms a first arm module receiving socket  214   a  sized to receive the first arm module  400   a , the support  210   b  forms a second arm module receiving socket (not shown) sized to receive the second arm module  400   b , the support  210   c  forms a third arm module receiving socket (not shown) sized to receive the third arm module  400   c , and the support  210   d  forms a fourth arm module receiving socket  214   d  sized to receive the fourth arm module  400   d.    
     The connectors shown in  FIGS.  3 F,  3 G, and  3 H  illustrate example arrangements of connecting components for connecting one or more arms to the hub module. It should be noted that some embodiments may not include arms or connectors (blind or otherwise). Further, in some embodiments the connectors may be used only for transmission of power to arm-mounted motors and not for connecting one or more arms to the hub module. 
     As best shown in  FIG.  3 F , female blind mate assemblies are attached to the free ends of the hollow supports  210   a - 210   d . Specifically, a first female blind mate assembly  230   a  is attached to the free end of the support  210   a  near the first arm module receiving socket  214   a , a second female blind mate assembly  230   b  is attached to the free end of the support  210   b  near the second arm module receiving socket, a third female blind mate assembly  230   c  is attached to the free end of the support  210   c  near the third arm module receiving socket, and a fourth female blind mate assembly  230   d  is attached to the free end of the support  210   d  near the fourth arm module receiving socket  214   d.    
     The female blind mate assemblies  230  (along with the corresponding male blind mate connectors described below with respect to the arm modules) facilitate mechanical attachment of the arm modules  400   a ,  400   b ,  400   c , and  400   d  to the hub module  100 . 
       FIGS.  3 G and  3 H  show the second female blind mate assembly  230   b . The female blind mate assemblies  230   a ,  230   c , and  230   d  are similar to the second female blind mate assembly  230   b  and are therefore not separately shown or described. 
     The second female blind mate assembly  230   b  includes: (1) a female blind mate connector  231   b  including a plurality of pin receptacles (not labeled); (2) three elastomeric grommets  232   b ; (3) three rigid, hollow cylindrical spacers  233   b ; (4) three fasteners  234   b ; (5) three nuts  235   b ; (6) a mounting bracket  236   b ; and (7) mounting bracket fasteners (not labeled). 
     The mounting bracket  236   b  is positioned at a desired location along the hollow support  210   b , and the mounting bracket fasteners are tightened to clamp the mounting bracket  236   b  in place relative to the hollow support  210   b.    
     The female blind mate connector  231   b  is flexurally mounted to the mounting bracket  236   b  via the elastomeric grommets  232   b , the spacers  233   b , the fasteners  234   b , and the nuts  235   b . Specifically, the elastomeric grommets  232   b  are fitted into corresponding cavities in the female blind mate connector  231   b . As best shown in  FIG.  3 H , each cavity includes an inwardly-projecting annular rib that fits into a corresponding annular cutout of the corresponding elastomeric grommet  232   b . The spacers  233   b  are disposed within longitudinal bores defined through the elastomeric grommets  232   b . The fasteners  234   b  extend through the hollow spacers  233   b  and through corresponding fastener receiving openings defined through the mounting bracket  236   b  into their corresponding nuts  235   b . This secures the female blind mate connector  231   b  to the mounting bracket  236   b.    
     This flexural mount of the female blind mate connector to the mounting bracket via the elastomeric grommets is beneficial compared to a rigid connection of the female blind mate connector to the mounting bracket. The flexural mount enables the female blind mate connector to move—via deformation of the elastomeric grommet—relative to the mounting bracket (and the rest of the hub module) when loads are applied to the female blind mate connector, such as loads imposed on the female blind mate connector by the attached arm module during flight. Because the female blind mate connector is not rigidly attached to the corresponding mounting bracket, it is less likely that the pins of the male blind mate connector (described below) received by the pin receptacles of the female blind mate connector will break when loads are applied to the female blind mate connector. 
     As best shown in  FIG.  3 H , a latch plate  237  is attached to the underside of each hollow support  210   a  and  210   b  below each female blind mate connector  231  attached thereto. The latch plate  237  includes a claw engager  238  and a backstop  239 . The latch plate  237  is described below with respect to the locking assemblies  420  of the arm modules  400   a  to  400   d.    
       FIGS.  3 I- 3 Q  show the saddle  300  or components thereof. The saddle  300  is the portion of the hub module  100 : (1) to which the fixed-wing aircraft  30  is attached for launch; (2) from which the fixed-wing aircraft  30  is released for launch. 
     This embodiment of the saddle  300  is sized, shaped, arranged, and otherwise configured to attach to and release the fixed-wing aircraft  30  without requiring any modification to the fixed-wing aircraft  30 . The size, shape, arrangement, and configuration of the components of the saddle  300  may be modified such that the saddle  300  can attach to and release other fixed-wing aircraft (such as the fixed-wing aircraft  30 ). 
     The saddle  300  includes a saddle base bracket  6310  and first and second saddle side brackets  6312  and  6314  straddling the saddle base bracket  6310 . A cross-brace  6318  is connected to and extends between the first and second saddle side brackets  6312  and  6314  near their back ends. As described in more detail below, the front ends of the first saddle side bracket  6312 , the second saddle side bracket  6314 , and the saddle base bracket  6310  are connected or otherwise mounted to a front engager  6320  such that the front engager  6320  can rotate relative to the first saddle side bracket  6312 , the second saddle side bracket  6314 , and the saddle base bracket  6310 . Although not shown for clarity, the saddle base bracket  6310  is fixedly connected to the hub base via suitable mounting brackets, and the first and second saddle side brackets  6312  and  6314  are fixedly connected to the hub base via suitable fasteners. 
     As best shown in  FIGS.  3 J and  3 K , the front engager  6320  includes: a shaft  6321 ; first and second leading-edge engagers  6323  and  6326 ; sleeve bearings  6322 ,  6324 ,  6325 , and  6327 ; and a stabilizer  6328 . 
     The first leading-edge engager  6323  includes a generally triangular base  6323   a  having a tube  6323   c  extending therefrom. A shaft-receiving bore (not labeled) extends through the base  6323   a  and the tube  6323   c . The base  6323   a  defines a contoured leading edge engaging surface  6323   b  that is shaped to receive and engage the portion of the leading edge of the wing of the fixed-wing aircraft  30  to which the saddle  300  will attach, as described below. The base  6323   a  includes a plurality of strengthening ribs extending outward from the tube  6323   c . Similarly, the second leading-edge engager  6326  includes a generally triangular base  6326   a  having a tube  6326   c  extending therefrom. A shaft-receiving bore (not labeled) extends through the base  6326   a  and the tube  6326   c . The base  6326   a  defines a contoured leading edge engaging surface  6326   b  that is shaped to receive and engage the portion of the leading edge of the wing of the fixed-wing aircraft  30  to which the saddle  300  will attach, as described below. The base  6326   a  includes a plurality of strengthening ribs extending outward from the tube  6326   c.    
     As noted above, the front engager  6230  is connected or otherwise mounted to the saddle base bracket  6310  and the first and second saddle side brackets  6312  and  6314  such that the front engager  6320  is rotatable relative to those components. The saddle base bracket  6310  includes a tubular mounting portion  6310   a  that defines a shaft-receiving bore therethrough. Part of the shaft  6321  is received in the shaft-receiving bore of the tubular mounting portion  6310   a  such that first and second free ends of the shaft are positioned on opposing sides of the tubular mounting portion  6310   a . The shaft  6321  is rotatably fixed relative to the saddle base bracket  6310 , though in other embodiments the shaft  6321  may rotate relative to the saddle base bracket  6310 . Suitable bearings may be incorporated at the interfaces between the saddle base bracket and the shaft to facilitate rotation of the shaft relative to the saddle base bracket. 
     The first and second leading-edge engagers  6323  and  6326  are rotatably mounted to the shaft  6321  on opposite sides of the tubular mounting portion  6310   a  of the saddle base bracket  6310  via the sleeve bearings  6322 ,  6324 ,  6325 , and  6327 . Specifically, the sleeve bearings  6322  and  6324  are press fit into the opposing ends of the shaft-receiving bore through the first leading-edge engager  6323  such that the sleeve bearings  6322  and  6324  cannot rotate relative to the first leading-edge engager  6323 . Part of the shaft  6321  is received in the sleeve bearings  6322  and  6324  and the shaft-receiving bore of the first leading-edge engager  6323  such that the first end of the shaft  6321  protrudes from the sleeve bearing  6324 . The first end of the shaft  6321  is received in a first retaining element  6329   a  fixedly attached to the second saddle side bracket  6314 . The first retaining element  6329   a  prevents substantial axial movement of the shaft  6321  relative to the first retaining nub  6329   a , and retains the first leading-edge engager  6323  on the shaft  6321 . At this point, the first leading-edge engager  6323  is mounted to the shaft  6321  via the sleeve bearings  6322  and  6324  such that the first leading-edge engager  6323  is rotatable about the longitudinal axis of the shaft  6321  relative to the saddle base bracket  6310 . The longitudinal axis of the shaft  6321  is above the leading edges of the wings of the fixed-wing aircraft  30 . 
     Similarly, the sleeve bearings  6325  and  6327  are press fit into the opposing ends of the shaft-receiving bore through the second leading-edge engager  6326  such that the sleeve bearings  6325  and  6327  cannot rotate relative to the second leading-edge engager  6326 . Part of the shaft  6321  is received in the sleeve bearings  6325  and  6327  and the shaft-receiving bore of the second leading-edge engager  6326  such that the second end of the shaft  6321  protrudes from the sleeve bearing  6325 . The second end of the shaft  6321  is received in a second retaining element  6329   b  fixedly attached to the first saddle side bracket  6312 . The second retaining element  6329   b  prevents substantial axial movement of the shaft  6321  relative to the second retaining element  6329   a , and retains the second leading-edge engager  6326  on the shaft  6321 . At this point, the second leading-edge engager  6326  is mounted to the shaft  6321  via the sleeve bearings  6325  and  6327  such that the second leading-edge engager  6326  is rotatable about the longitudinal axis of the shaft  6321  relative to the saddle base bracket  6310 . 
     The stabilizer  6328  is attached to the base  6323   a  of the first leading-edge engager  6323  and to the base  6326   a  of the second leading-edge engager  6326  such that the stabilizer  6328  extends between and connects the first and second leading-edge engagers  6323  and  6326 . The stabilizer  6328  ensures the first and second leading-edge engagers  6323  and  6326  rotate relative to the saddle base bracket  6310  and the first and second saddle side brackets  6312  and  6314  substantially simultaneously rather than independently of one another. 
     As best shown in  FIGS.  3 J and  3 M , an aircraft attaching/releasing assembly  6340  is attached to the saddle base bracket  6310  and to the front engager  6320  and controls rotation of the first engager  6320  about the longitudinal axis of the shaft  6321  relative to the saddle base bracket  6310 . As best shown in  FIG.  3 N , the aircraft attaching/releasing assembly  6340  includes: a front engager servo motor  6345  having a front engager servo motor shaft  6345   a , a front engager arm  6342 , a front engager arm lock device  6342   a , a servo spacer  6344 , first and second nut plates  6347   a  and  6347   b , fasteners  6348  and corresponding nuts  6348   a , a front engager rotation control link  6343  having connectors  6343   a  and  6343   b  at opposite ends, a lock servo motor  6341  having a lock servo motor shaft  6341   a , a lock arm  6346  terminating at one end in a locking extension  6346   a , and first and second front engager attachment brackets  6349   a  and  6349   b.    
     The front engager servo motor  6345  and the lock servo motor  6341  are attached to one another and to the saddle base bracket  6310  via the fasteners  6348 , the servo spacer  6344 , the first and second nut plates  6347   a  and  6347   b , and the nuts  6348   a.    
     The front engager arm  6342  is attached near one end to the front engager servo motor shaft  6345   a  and near the other end to the connector  6343   a . The connector  6343   b  is attached to the stabilizer  6328  of the front engager  6320  via the first and second front engager attachment brackets  6349   a  and  6349   b  (such as via suitable fasteners, not shown). This operatively links the front engager servo motor shaft  6345   a  to the front engager  6320 . The front engager arm lock device  6342   a  is attached to the front engager arm  6342  between the connector  6343   a  and the front engager servo motor shaft  6345   a.    
     The lock arm  6346  is attached to the lock servo motor shaft  6341   a  near one end. The free end of the lock arm  6346  terminates in the locking extension  6346   a , which is engageable to the front engager arm lock device  6342   a  in certain instances to prevent clockwise (from the viewpoint shown in  FIGS.  3 O- 3 Q ) rotation of the front engager arm  6342 . 
     The front engager servo motor  6345  controls rotation of the front engager  6320  (and, specifically, the first and second leading-edge engagers  6323  and  6326 ) about the longitudinal axis of the shaft  6321  relative to the saddle base bracket  6310 . To rotate the front engager  6320 , the front engager servo motor  6345  rotates the front engager servo motor shaft  6345   a , which rotates the attached front engager arm  6342 , which in turn rotates the front engager  6320  via the front engager rotation control link  6343 . The front engager servo motor  6345  can rotate the front engager  6320  between an attached rotational position—shown in  FIGS.  3 O and  3 P —and a release rotational position—shown in  FIG.  3 Q . 
     The lock servo motor  6341  controls rotation of the lock arm  6346  between a front engager rotation-preventing rotational position—shown in  FIG.  3 O —and a front engager rotation-enabling rotational position—shown in  FIGS.  3 P and  3 Q . When the front engager  6320  is in the attached rotational position and the lock arm  6346  is in the front engager rotation-preventing rotational position, the locking extension  6346   a  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . This prevents the front engager servo motor  6345  from rotating the front engager  6320  clockwise (from the viewpoint shown in  FIGS.  3 O- 3 Q ) from the attached rotational position to the release rotational position. As best shown in  FIG.  2 O , the servo spacer  6344  prevents counter-clockwise rotation (from the viewpoint shown in  FIGS.  3 O- 3 Q ) of the front engager arm  6342 . 
       FIGS.  3 O- 3 Q  show how the front engager servo motor  6345  and the lock servo motor  6341  cooperate to rotate the front engager  6320  from the attached rotational position to the release rotational position. Initially, the front engager arm  6342  is in the attached rotational position and the lock arm  6346  is in the front engager rotation-preventing rotational position. Here, the locking extension  6346   a  on the end of the lock arm  6346  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . 
     Since the locking extension  6346   a  engages the front engager lock device  6342   a  of the front engager arm  6342 , the front engager servo motor  6345  cannot rotate the front engager  6320  from the attached rotational position to the release rotational position (clockwise from this viewpoint). And as indicated above, the servo spacer  6344   b  prevents counter-clockwise rotation of the front engager arm  6342  (from this viewpoint). 
     Rotating the front engager  6320  from the attached rotational position to the release rotational position is a two-step process. As shown in  FIG.  3 P , the operator first operates the lock servo motor  6341  to rotate the lock arm  6346  into the front engager rotation-enabling rotational position (clockwise from this viewpoint). Second, as shown in  FIG.  3 Q , the operator operates the front engager servo motor  6345  to rotate the front engager  6320  from the attached rotational position to the release rotational position (clockwise from this viewpoint). 
     As shown in  FIG.  3 J , separate (but in this embodiment, identical) rear engagers  6360  (here, trailing-edge engagers) are attached to the first and second saddle side brackets  6312  and  6314 . As best shown in  FIGS.  3 L and  3 M , the rear engager  6360  includes a body  6362  and a pivotable portion  6364  pivotably connected to the body  6362  via a suitable pivot shaft (not shown). The body  6362  includes a trailing edge engaging surface  6362   a . The pivotable portion  6364  includes multiple surfaces that define a trailing edge receiving channel  6364   a  sized and shaped to receive the trailing edge of a wing of the fixed-wing aircraft  30 . Fasteners  6366  are threadably received in the pivotable portion  6364 . The fasteners  6366  engage the top surface of the wing of the fixed-wing aircraft  30 , and can be threaded further into or further out of the pivotable portion  6364  as desired to adjust clearance between the pivotable portion  6364  and the exterior upper surface of the wing. In one embodiment, the fasteners are formed from a relatively soft material, such as Teflon, and the pivotable portion is formed from a relatively harder material, such as aluminum. 
     The body  6362  is fixedly attached to the appropriate saddle side bracket via suitable fasteners (not shown for clarity) such that the trailing edge engaging surface  6362   a  and the pivotable portion  6364  extend below the body  6362 . 
     In operation, the operator attaches the hub module  100  to the fixed-wing aircraft  30  by: (1) operating the front engager servo motor  6345  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the release rotational position; (2) inserting the trailing edges of the wings of the fixed-wing aircraft  30  into the trailing edge receiving channels  6364   a  of the pivotable portions  6364  of the rear engagers  6360 ; (3) positioning the saddle  300  relative to the fixed-wing aircraft  30  such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  are adjacent the leading edges of the wings of the fixed-wing aircraft  30 ; (4) operating the front engager servo motor  6345  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the attached rotational position such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  contact the leading edges of the wings of the fixed-wing aircraft  30 ; and (5) operating the lock servo motor  6341  (either manually or remotely via the R/C controller) to rotate the lock arm  6346   a  into the front engager rotation-preventing rotational position so the locking extension  6346   a  on the end of the lock arm  6346  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . 
     At this point the fixed-wing aircraft  30  is attached to the saddle  300  (and the aircraft-launch apparatus  10 ) because the front engager  6320  and the rear engagers  6360  engage the wings of the fixed-wing aircraft  30  therebetween. The pivotable portions  6364  of the rear engagers  6360  are rotationally positioned relative to the bodies  6362  of the rear engagers  6360  such that the trailing-edge engaging surfaces  6362   a  are not within the trailing-edge receiving channels of the pivotable portions  6364 . The positioning of the servo spacer  6344   b  and the fact that the locking extension  6346   a  is engaged to the front engager arm lock device  6342   a  of the front engager arm  6342  ensure the front engager servo motor  6345  cannot rotate the front engager  6320  from the attached rotational position to the release rotational position. This prevents undesired release of the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ). 
     Releasing the fixed-wing aircraft  30  from the saddle  300  while the aircraft-launch apparatus  10  is airborne is a two-step process shown in  FIGS.  3 P and  3 Q . To release the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ), the operator first remotely controls the lock servo motor  6341  (via the R/C controller) to rotate the lock arm  6346  into the front engager rotation-enabling rotational position, as shown in  FIG.  3 P . Second, the operator remotely controls the front engager servo motor  6345  (via the R/C controller) to rotate the front engager  6320  from the attached rotational position to the release rotational position, as shown in  FIG.  3 Q . As the front engager servo motor  6345  rotates the front engager  6320  from the attached rotational position to the release rotational position, the first and second leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  rotate away from and begin to lose contact with the leading edge of the wing of the fixed-wing aircraft  30 . As the front engager  6320  continues to rotate clear of the wings of the fixed-wing aircraft  30 , the pivotable portions  6364  of the rear engagers  6360  enable the fixed-wing aircraft  30  to freely pivot relative to the saddle base bracket  6310 , the first and second saddle side brackets  6312  and  6314 , and the bodies  6362  of the rear engagers  6360  as gravity pulls the fixed-wing aircraft  30  downward. The center of gravity of the fixed-wing aircraft  30  is positioned forward of the rear engagers. As this occurs, the trailing edge engaging surfaces  6362   a  of the bodies  6362  of the rear engagers  6360  gradually enter the trailing-edge receiving channels of the pivotable portions  6364 . As this occurs, the trailing-edge engaging surfaces  6362   a  contact the trailing edge of the wings and force them out of the trailing edge receiving channels, thus releasing the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ) into free flight. 
     As the fixed-wing aircraft  30  rotates downward, its empennage rises relative to the aircraft-launch apparatus  10  as the nose of the fixed-wing aircraft  30  drops. The rear engagers are configured such that the trailing edges of the wings of the fixed-wing aircraft  30  are forced out of the trailing edge receiving channels before the empennage of the fixed-wing aircraft  30  contacts the aircraft-launch apparatus  10 . 
     As noted above, this embodiment of the saddle  300  may be sized, shaped, arranged, and otherwise configured to attach to and release any suitable fixed-wing aircraft by clamping its wings between front and rear engagers. An operator could—without changing any other components of the aircraft-launch apparatus  10 —swap out one saddle base bracket, front engager, and rear engager combination (or the entire saddle including those components) configured for one type of aircraft with another saddle base bracket, front engager, and rear engager combination (or the entire saddle including those components) configured for a different type of aircraft. This adds yet another layer of modularity to the aircraft-launch apparatus  10  and enables it to carry many different types of fixed-wing aircraft without requiring any modification of those fixed-wing aircraft. 
     In other embodiments, the saddle may be the saddle described in U.S. Patent Application Publication No. 2017/0158318, the entire contents of which are incorporated herein by reference. That saddle is configured to attach to the fixed-wing aircraft  30  via a hook of the fixed-wing aircraft  30  (or any other fixed-wing aircraft including a suitable hook). 
     The arm modules  400   a  to  400   d  are mechanically attachable to and mechanically lockable to the hub module  200  and include locking assemblies that lock the arm modules  400   a  to  400   d  to the hub module  100 .  FIGS.  3 R- 3 V  show the first arm module  400   a  and components thereof. The other arm modules  400   b ,  400   c , and  400   d  are similar to the first arm module  400   a  and are therefore not separately shown or described. 
     As best shown in  FIG.  3 R , the first arm module  400   a  includes a generally rectangular elongated tubular arm  410   a , a generally rectangular tubular first arm extension  410   b , a generally rectangular second arm extension  410   c , a locking assembly  420 , and a male blind mate connector  431 . 
     The first arm extension  410   b  is attached to the arm  410   a  such that part of the first arm extension  410   b  is disposed within the arm  410   a  and the remainder of the first arm extension  410   b  extends from the arm  410   a . Similarly, the second arm extension  410   c  is attached to the arm  410   a  such that part of the second arm extension  410   c  is disposed with in the arm  410   a  and the remainder of the arm extension  410   c  extends from the arm  410   a . The locking assembly  420  is attached to the underside of the arm  410   a  near the end of the arm  410   a  from which the first arm extension  410   b  extends. The male blind mate connector  431  is attached to the end of the arm  410   a  from which the arm extension  410   b  extends. 
     As best shown in  FIGS.  3 T- 3 V , the male blind mate connector  431 —along with its counterpart female blind mate connector  231   a  of the hub module  100 —facilitate mechanical attachment of the first arm module  400   a  to the hub module  100 . The male blind mate connector  431  includes a plurality of pins  431   a  configured to mate with the pin receptacles of the female blind mate connector  231   a.    
     To attach the first arm module  400   a  to the hub module  100 , an operator inserts the arm extension  410   b  into the first arm module receiving socket  214   a  of the hub module  100  and slides the first arm module  400   a  toward the hub module  100  with enough force to mate the pins of the male blind mate connector  431  with the pin receptacles of the female blind mate connector  231   a  of the hub module  100 . 
     As best shown in  FIGS.  3 S- 3 V , the locking assembly  420  includes a drawcatch  420   a  and a drawcatch lock  420   b  that facilitate attaching the first arm module  400   a  to the hub module  100 , lock the first arm module  400   a  to the hub module  100 , and facilitate detaching the first arm module  400   a  from the hub module  100 . 
     As best shown in  FIG.  3 S , the drawcatch  420   a  includes a base  421 , a lever  422 , a claw  423 , a first fastener  424  (such as a clevis pin or other suitable fastener), and a second fastener  425  (such as a clevis pin or other suitable fastener). The drawcatch lock  420   b  includes a base  426 , a lock/release device  427  having a locking shelf  427   a , a pin  428  (or other suitable connector), and a compression spring  429  (or other suitable biasing element). 
     The base  421  is attached to the underside of the arm  410   a . The lever  422  is pivotably connected at one end to the base  421  via the first fastener  424 . The other end of the lever  422  includes a handle  422   a . The claw  423  is pivotably connected at one end to the lever  422  via the second fastener  425 . The other end of the claw includes a latch plate engager  423   a.    
     The base  426  is attached to the underside of the arm  410   a . The lock/release device  427  is pivotably connected to the base  426  via the pin  428 . The compression spring  429  is disposed between the base  426  and the lock/release device  427  and retained in place via cavities and/or projections defined in or extending from these components (not shown). 
     The lock/release device  427  is rotatable about the pin  428  from a lock rotational position to a release rotational position. The compression spring  429  biases the lock/release device  427  to the lock rotational position. To rotate the lock/release device  427  from the lock rotational position to the release rotational position, the operator pushes the lock/release device  427  inward with enough force to overcome the spring-biasing force and compress the compression spring  429 . 
     The operator uses the locking assembly  420  to lock the male blind mate connector  431  with the female blind mate connector  231   a  as follows. The operator rotates the handle  422   a  of the lever  422  around the first fastener  424  toward the latch plate  237  on the hollow support  210   a  of the hub module  100  and engages the claw engager  238  of the latch plate  237  with the latch plate engager  423   a  of the claw  423 . The operator then rotates the handle  422   a  around the first fastener  424  and toward the lock/release device  427  until the handle  422   a  contacts the lock/release device  427 . Continued rotation of the lever  422  forces the lock/release device  427  inward, which overcomes the spring-biasing force and begins compressing the compression spring  429 . This causes the lock/release device  427  to being rotating to the release rotational position. Once the handle  422  rotates past the locking shelf  427   a , the spring-biasing force of the compression spring  429  causes the lock/release device  427  to rotate back to the lock rotational position. At this point, the locking shelf  427   a  prevents the handle  422  from rotating back toward the latch plate  237 , and the first arm module  400   a  and the hub module  100  are locked together. 
     As shown in  FIGS.  3 T- 3 V , the operator reverses this process to unlock the first arm module  400   a  from the hub module  100 . The operator pushes the lock/release device  427  inward with enough force to overcome the spring-biasing force and to compress the compression spring  429 , which causes the lock/release device  427  to rotate to the release rotational position. This frees the handle  422   a  to rotate. Once the handle  422   a  rotates past the locking shelf  427   a , the operator rotates the handle  422   a  of the lever  422  around the first fastener  424  toward the latch plate  237  and disengages the latch plate engager  423   a  of the claw  423  from the claw engager  238  of the latch plate  237 . 
     At this point, the operator can either physically pull the first arm module  400   a  and the hub module  100  apart to separate the male and female blind mate connectors  431  and  231   a  or use the locking assembly  420  to aid in detachment. When using the locking assembly  420  to aid in detachment, as shown in  FIG.  3 U , after disengaging the latch plate engager  423   a  from the claw engager  238 , the operator continues rotating the handle  422   a  toward the latch plate  237  until the latch plate engager  423   a  contacts the backstop  239  of the latch plate  237 . Afterward, continued rotation of the handle  422   a  toward the latch plate  237  causes the latch plate engager  423   a  to impose a pushing force against the backstop  239 , which forces the first arm module  400   a  and the hub module  100  apart. 
       FIG.  3 W  shows the first front landing gear module  600   a . The front landing gear modules (along with the rear landing gear modules, described below) support the aircraft-launch apparatus  10  when assembled but not flying, and facilitate launch and landing of the aircraft-launch apparatus  10  without damaging the aircraft-launch apparatus  10 . The second front landing gear module  600   b  is similar to the first front landing gear module  600   a  and is therefore not separately shown or described. 
     The first front landing gear module  600   a  includes a base  640   a , a generally cylindrical leg  620   a  attached to and extending from the base  640   a , and a generally rectangular tubular arm module receiving arm  610   a  attached to and extending from the base  640   a . The leg  620   a  terminates in a generally semicircular foot  630   a . The arm module receiving arm  610   a  defines an arm module receiving socket (not labeled) sized to receive the first arm module  400   a.    
     The operator attaches the first front landing gear module  600   a  to the first arm module  400   a  by inserting the free end of the second arm extension  410   c  into the arm module receiving socket of the arm module receiving arm  610   a  of the first front landing gear module  600   a . The operator then locks these two modules together, such as via suitable fasteners. 
       FIG.  3 X  shows the first rear landing gear module  600   c . The rear landing gear modules (along with the front landing gear modules, described above) support the aircraft-launch apparatus  10  when assembled but not flying, and facilitate launch and landing of the aircraft-launch apparatus  10  without damaging the aircraft-launch apparatus  10 . The rear landing gear modules are shaped such that they act as vertical stabilizers (or fins) during flight, ensuring that the front of the aircraft-launch apparatus  10  (and the nose of the fixed-wing aircraft  30 , if attached thereto) points generally into the airflow when in flight. The second rear landing gear module  600   d  is similar to the first rear landing gear module  600   c  and is therefore not separately shown or described. 
     The first rear landing gear module  600   c  includes a body  670   c  having a generally triangular cross-section that tapers from front to back. The body  670   c  transitions at its bottom into a generally circular foot  680   c . A generally rectangular tubular arm module receiving arm  690   c  is attached to and extends through the body  670   c.    
     The operator attaches the first rear landing gear module  600   c  to the third arm module  400   c  by inserting the free end of the third arm extension into the arm module receiving socket of the arm module receiving arm  690   a  of the first rear landing gear module  600   c . The operator then locks these two modules together, such as via suitable fasteners. 
     Once attached, the rear landing gear modules are oriented such that the side surfaces of the bodies of the rear landing gear modules are substantially aligned with the saddle side brackets  612  and  614  of the saddle  300 . When the fixed-wing aircraft  30  is attached to the aircraft-launch apparatus  10 , these side surfaces of the rear landing gear modules are substantially parallel to a plane containing the roll axis of the fuselage of the fixed-wing aircraft  30 . The relatively long length of these side surfaces of the rear landing gear modules cause the rear landing gear module to act as fins in flight. This weather vane effect ensures that the nose of the fixed-wing aircraft  30  is oriented into the airflow when airborne. 
     One or more operators may use the components of the aircraft launch system to launch the fixed-wing aircraft  30  into free, wing-borne flight. A single operator is referred to below for brevity and clarity. 
     To prepare for launch, the operator attaches the first and second winches  1110  and  1120  to suitable areas of the ship S in a suitable manner. In this example embodiment, the first winch  1110  is attached below the deck of the ship S while the second winch  1120  is attached to the deck of the ship S via mounting brackets and fasteners (not shown). The operator attaches one end of the first flexible member  1110   a  to the drum of the first winch  1110  and controls the first winch  1110  to retract most of the first flexible member  1110   a . Similarly, the operator attaches one end of the second flexible member  1120   a  to the drum of the second winch  1120  and controls the second winch  1120  to retract most of the second flexible member  1120   a.    
     The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the first winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is distributed between the left and right bridle sets of the parasail P. The operator may decide to bias the ballast to force the parasail to fly off to the left or right side of the ship. 
     In certain situations, the ship S may already be equipped with the first winch, the first flexible member, the parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to launch the fixed-wing aircraft into free, wing-borne flight. 
     The operator positions the fixed-wing aircraft  30  on the deck, such as on a launch-assist structure that can be removably attached to the deck and that retains the fixed-wing aircraft in a desired orientation. The operator attaches the hub module  100  of the aircraft-launch apparatus  10  to the fixed-wing aircraft  30  by: (1) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the release rotational position; (2) inserting the trailing edges of the wings of the fixed-wing aircraft  30  into the trailing edge receiving channels  6364   a  of the pivotable portions  6364  of the rear engagers  6360 ; (3) positioning the saddle  300  relative to the fixed-wing aircraft  30  such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  are adjacent the leading edges of the wings of the fixed-wing aircraft  30 ; (4) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the attached rotational position such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  contact the leading edges of the wings of the fixed-wing aircraft  30 ; and (5) operating the lock servo motor  6345  (either manually or remotely via the R/C controller) to rotate the lock arm  6346   a  into the front engager rotation-preventing rotational position so the locking extension  6346   a  on the end of the lock arm  6346  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . 
     In some example embodiments, the rear engager may be linked to the front engager, such that the rear engager disengages the trailing edge wing root as the front engager releases the leading edge wing root. This is illustrated in  FIGS.  3 CC  and  3 DD. The rear engager  350  is linked to the front engager  352  by a linking mechanism  354 , such that when the front engager  352  releases, the rear engager  350  also releases. The release process is shown in  FIG.  3 DD . 
     The use of the linking mechanism may allow both the front engager  352  and rear engager  350  to be actuated, causing an engaged aircraft to have no more coupling to the hub. Other embodiments may include a “center of gravity hook” or other component of the aircraft that is used to couple the aircraft to the hub. However by using the linking mechanism to control both the front engager and rear engager, the hook is no longer needed. Removal of the hook can remove drag and weight from the aircraft, and allow any fixed-wing aircraft of suitable size to be coupled to the hub and released. 
     In some examples, the front engager may be actuated and thereby cause the rear engager to actuate via the linking mechanism. In this case, the aircraft may only actuate the front engager, and may not have a separate actuator for the rear engager. In other examples, both the front engager and the rear engager may have separate actuators configured to move them individually. Still further, in some examples the rear engager may be coupled to an actuator that causes it to move, and via the linking mechanism, may cause the front engager to move as well. 
     At this point the fixed-wing aircraft  30  is attached to the saddle  300  because the front engager  6320  and the rear engagers  6360  engage the wings of the fixed-wing aircraft  30  therebetween. The pivotable portions  6364  of the rear engagers  6360  are rotationally positioned relative to the bodies  6362  of the rear engagers  6360  such that the trailing-edge engaging surfaces  6362   a  are not within the trailing-edge receiving channels of the pivotable portions  6364 . The positioning of the servo spacer  6344   b  and the fact that the locking extension  6346   a  is engaged to the front engager arm lock device  6342   a  of the front engager arm  6342  ensure the front engager servo motor  6341  cannot rotate the front engager  6320  from the attached rotational position to the release rotational position. This prevents undesired release of the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ). 
     After the hub module  100  is attached to the fixed-wing aircraft  30 , the operator attaches the front and rear landing gear modules  600   a  to  600   d  to their respective arm modules  400   a  to  400   d  and attaches and locks the arm modules  400   a  to  400   d  to the hub module  100  to complete assembly of the aircraft-launch apparatus  10 . 
     The operator starts up the engine of the fixed-wing aircraft  30 , and controls the ship S to head into the wind and maintain this course throughout the launch process. 
     The operator opens the parasail P and controls the first winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height. At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. As shown in  FIG.  1 A , the operator attaches the first flexible member attachment device  1112  (and its attached one-way pulley  1114 ) to the first flexible member  1110  a first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. After attachment, the first flexible member attachment device  1112  is movable along the first flexible member  1110  toward the parasail P but not in the opposite direction. 
     The operator feeds the free end of the second flexible member  1120   a  through a guide loop (not labeled) on a mast M of the ship S, wraps the second flexible member  1120   a  around the wheel of the pulley  1114 , and attaches the free end of the second flexible member  1120   a  to the snag-prevention member  299  of the aircraft-launch apparatus  10 . This attaches the aircraft-launch apparatus  10  to the second winch  1120  and the first flexible member  1110   a  to the second flexible member  1120   a . The operator controls the second winch  1120  to retract the second flexible member  1120   a  and remove any slack in the second flexible member  1120   a , which draws the pulley  1114  and the snag-prevention member  299  together. Once the slack is removed and the snag-prevention member  299  is at or near the pulley  1114 , the operator controls the second winch  1120  to maintain enough tension in the second flexible member  1120   a  to retain the snag-prevention member  299  (and therefore the aircraft-launch apparatus  10 ) at or near the pulley  1114 . 
     As shown in  FIG.  1 B , the operator controls the first and second winches  1110  and  1120  such that the first and second flexible members  1110   a  and  1120   a  are respectively paid out from the first and second winches  1110  and  1120 . More specifically, in this example embodiment, the operator controls: (1) the first winch  1110  to actively payout the first flexible member  1110   a ; and (2) the second winch  1120  to maintain sufficient tension in the second flexible member  1120   a  to retain the aircraft-launch apparatus  10  at or near the pulley  1114 . As the first winch  1110  pays out the first flexible member  1110   a , it causes the second winch  1120  to backdrive and payout the second flexible member  1120   a  (since they&#39;re connected via the first flexible capture member attachment device  1112 ) while retaining the aircraft-launch apparatus  10  at or near the pulley  1114  (since the second winch  1120  maintains sufficient tension in the second flexible member  1120   a  and the wheel of the pulley  1114  resists lowering of the aircraft-launch apparatus  10 ). In other embodiments, the operator simultaneously controls the first and second winches to actively payout the first and second flexible members, respectively, rather than relying on the first winch causing the second winch to backdrive to payout the second flexible member. 
     As the first and second flexible members  1110   a  and  1120   b  are paid out from the respective first and second winches  1110  and  1120 , the parasail P ascends via the wind and the continued motion of the ship S and lifts the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  off of the deck of the ship S. Once the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  are airborne, as the ship S travels into the wind, the rear landing gear of the aircraft-launch apparatus  10  act as vertical stabilizers (or fins) that ensure that the front of the aircraft-launch apparatus  10  and the nose of the attached fixed-wing aircraft  30  point generally into the wind. 
     The operator controls the first and second winches  1110  and  1120  to stop paying out the first and second flexible members  1110   a  and  1120   a , respectively, once about 700 feet (or any other suitable amount) of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. More specifically, in this example embodiment, the operator controls the first winch  1110  to stop actively paying out the first flexible member  1110   a  once about 700 feet of the first flexible member  1110   a  extend between the first winch and the parasail P. This stops the first flexible member  1110   a  from causing the second winch  1120  to backdrive to pay out the second flexible member  1120   a.    
     As shown in  FIG.  1 C , at this point the operator controls the second winch  1120  to payout the second flexible member  1120   a  such that gravity pulls the aircraft-launch apparatus  10  and attached fixed-wing aircraft  30  downward relative to the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114 . While the pulley  1114  resists descent of the aircraft-launch apparatus  10  relative to the pulley  1114  (e.g., where pulley  1114  is a one-way pulley), the aircraft-launch apparatus  10  is heavy enough such that gravity overcomes this resistive force. The operator controls the second winch  1120  to stop paying out the second flexible member  1120   a  once about 100 feet (or any suitable amount) of the second flexible member extends between the pulley  1114  and the aircraft-launch apparatus  10 . This provides a buffer area between the fixed-wing aircraft  30  and the first flexible member  1110   a  that reduces the likelihood of the fixed-wing aircraft  30  contacting the first flexible member  1110   a  after release. 
     If the aircraft is not heavy enough to overcome sliding friction of the pulley  1114  where pulley  1114  is a one-way pulley, a two way pulley may be used in its place. 
     The operator then controls the aircraft-launch apparatus  10  to release the fixed-wing aircraft  30  from the saddle  300 , as shown in  FIG.  1 D . Releasing the fixed-wing aircraft  30  from the saddle  300  is a two-step process. To release the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ), the operator first remotely controls the lock servo motor  6345  (via the R/C controller) to rotate the lock arm  6346  into the front engager rotation-enabling rotational position. Second, the operator remotely controls the front engager servo motor  6341  (via the R/C controller) to rotate the front engager  6320  from the attached rotational position to the release rotational position. As the front engager servo motor  6341  rotates the front engager  6320  from the attached rotational position to the release rotational position, the first and second leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  rotate away from and begin to lose contact with the leading edge of the wing of the fixed-wing aircraft  30 . As the front engager  6320  continues to rotate clear of the wings of the fixed-wing aircraft  30 , the pivotable portions  6364  of the rear engagers  6360  enable the fixed-wing aircraft  30  to freely pivot relative to the saddle base bracket  6310 , the first and second saddle side brackets  6312  and  6314 , and the bodies  6362  of the rear engagers  6360  as gravity pulls the nose of the fixed-wing aircraft  30  downward. As this occurs, the trailing edge engaging surfaces  6362   a  of the bodies  6362  of the rear engagers  6360  gradually enter the trailing-edge receiving channels of the pivotable portions  6364 . As this occurs, the trailing-edge engaging surfaces  6362   a  contact the trailing edge of the wings and force them out of the trailing edge receiving channels, thus releasing the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus) into free, wing-borne flight. 
     After the fixed-wing aircraft  30  is released into free, wing-borne flight, the operator controls the second winch  1120  to retract the second flexible member  1120   a  such that the aircraft-launch apparatus  10  (and attached fixed-wing aircraft  30 ) ascends back toward the first flexible member  1110   a , the first flexible member attachment device  1112 , and the one-way pulley  1114 . The operator controls the second winch  1120  such that the second flexible member  1120   a  stops retracting once the aircraft-launch apparatus  10  reaches the pulley  1114 , yet maintains enough tension in the second flexible member  1120   a  to retain the aircraft-launch apparatus  10  at or near the pulley  1114 . 
     The operator then controls the first and second winches  1110  and  1120  to respectively retract the first and second flexible members  1110   a  and  1120   a  until the aircraft-launch apparatus  10  reaches the deck of the ship S, at which point the operator controls the winches to stop retracting. At this point, deck hands secure the aircraft-launch apparatus  10  and detach the first flexible member attachment device  1112  from the first flexible member  1110   a , which disconnects the first flexible member  1110   a  from the second flexible member  1120   a . The deck hands disassemble and stow the aircraft-launch apparatus  10 . The operator controls the first winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     In certain embodiments, the launch system includes a compliant structure, such as a trampoline, to aid in the launch process. In these embodiments, the compliant structure is erected over part of the deck of the ship (or other moving object), and the fixed-wing aircraft  30  is positioned on the compliant structure before (or after) the aircraft-launch apparatus  10  is attached to the fixed-wing aircraft  30 . The compliant structure acts as a damper that dampens forces that would otherwise be exerted on the aircraft-launch apparatus  10  and the fixed-wing aircraft  30  to be damaged as the ship S moves (especially in rough seas), which reduces the potential for damage to these apparatuses. 
     In other embodiments in which the saddle is that described in U.S. Patent Application Publication No. 2017/0158318, the fixed-wing aircraft launch method incorporates the procedure for releasing the fixed-wing aircraft from the saddle described in U.S. Patent Application Publication No. 2017/0158318. 
       FIGS.  3 Y and  3 Z  show an example aircraft launch apparatus  310  and a hoist  320 . Aircraft launch apparatus  310  may be similar or identical to aircraft launch apparatus  10  described above. Aircraft launch apparatus  310  is described in more detail below with respect to  FIG.  3 Z . 
       FIG.  3 Y  shows the aircraft launch apparatus  310  and a hoist  320 . The hoist  320  may be similar or identical in some respects to the hoist described with respect to  FIGS.  6 A-G  and  7 A-B below. In particular, the hoist  320  may include a winch or other mechanism configured to extend and/or retract a flexible member attached to the aircraft launch apparatus  310 . The flexible member may include a suitable rope or other similar flexible element. 
     The hoist  320  also includes a suitable device configured to removably attach to a first flexible member attached to a parasail to raise the hoist into the air. This is described in further detail with respect to  FIGS.  6 A-G  and  7 A-B. 
       FIG.  3 Z  illustrates an enlarged view of the aircraft launch apparatus  310 . Launch apparatus  310  may include a hub base  312  and a saddle  314 . The hub base  312  may be similar or identical to the hub base  200  described herein. Further, the saddle  314  may be similar or identical to the saddle  300  described elsewhere within this disclosure. In particular, a release mechanism of the saddle  314  may be similar or identical to a release mechanism of the saddle  300  described elsewhere. 
     The launch apparatus  310  may also include one or more trailing members  316 . These may be referred to as tail feathers, and may serve to maintain an orientation or direction of the launch apparatus  310 . The trailing members  316  may operate in a manner similar to the rear landing gear modules  600   c  and  600   d  described herein, specifically by maintaining the direction/orientation of the launch apparatus. Notably, however, the launch apparatus  310  may not include landing gear or other members configured to extend below an attached aircraft in order to touch down or land on a ship (such as landing gear modules  600   a - d  described with respect to  FIG.  3 C ). 
       FIG.  3 AA  illustrates the launch apparatus  310  having an aircraft attached to the saddle  314 . 
       FIG.  3 BB  illustrates an example embodiment wherein a launch cradle  340  is in an operating position and a stowed position. The launch cradle  340  may be configured to carry or hold an aircraft, removing the need for landing gear or other members to hold the aircraft prior to and after it is released and/or captured. The launch cradle  340  may be configured to rotate between the operating position generally horizontal to the deck of the ship, and the stowed position wherein the cradle  340  is vertical to the deck of the ship. This can allow for a reduced footprint on the ship. 
       FIG.  3 BB  also illustrates an example position of the storage device  330  of  FIG.  3 Y  on the ship. The storage device  330  of  FIG.  3 BB  may be configured to store the aircraft launch apparatus  310 , the hoist  320 , and/or one or more other components or devices described herein such as flexible members, aircraft components, hoists, winches, etc. The storage device  330  may be configured to fit onto a ship, such as those described herein. 
     1.2 Parasail-Assisted Fixed-Wing Aircraft Retrieval System and Method 
       FIGS.  2 A- 2 D  are diagrammatic views showing one example parasail-assisted fixed-wing aircraft retrieval system and method of the present disclosure. In this example embodiment, the aircraft retrieval system includes the parasail P, the ballast B, the first winch  1110 , the first flexible member  1110   a , the first flexible member attachment device  1112 , the one-way pulley  1114 , the second winch  1120 , the second flexible member  1120   a , a drag-producing device  1130 , a retrieval flexible member  1140 , and a GPS receiver  1150 . 
     The parasail P, the ballast B, the first winch  1110 , the first flexible member  1110   a , the first flexible member attachment device  1112 , the one-way pulley  1114 , the second winch  1120 , and the second flexible member  1120   a  are described above. 
     The retrieval flexible member  1140  is a suitable rope or other similar flexible element. 
     The drag-producing device  1130  is a suitable device configured to produce drag when being pulled through the air. In this example embodiment, the drag-producing device includes a parachute. 
     The global positioning system (GPS) receiver  1150  is communicatively connectable with (such as via a suitable wireless protocol) GPS satellites (not shown), as is known in the art. The GPS receiver  1150  is configured to receive signals from one or more of the GPS satellites, to determine the multicopter&#39;s location using those signals, and to transmit signals representing the multicopter&#39;s location to a suitable external device. In this example embodiment, the GPS receiver  1150  is removably connectable to the retrieval flexible member  1140  in any suitable manner, and is used to communicate the position of the retrieval flexible member to the control system of the fixed-wing aircraft  30  to enable retrieval (as described in detail below). 
     To prepare for retrieval, the operator controls the first winch  1110  to retract most of the first flexible member  1110   a  and controls the second winch to retract most of the second flexible member  1120   a . The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the first winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is generally evenly distributed between the left and right bridle sets of the parasail P. 
     In certain situations, the ship may already be equipped with the first winch, the first flexible member, the first parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to retrieve the fixed-wing aircraft from free, wing-borne flight. 
     The operator controls the ship S to head into the wind and maintain this course throughout the retrieval process. The operator opens the parasail P and controls the first winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height, as shown in  FIG.  2 A . At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. The operator then fixedly attaches the first flexible member attachment device  1112  (and its attached pulley  1114 ) to the first flexible member  1110  the first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. After attachment, the first flexible member attachment device  1112  is movable along the first flexible member  1110  toward the parasail P but not in the opposite direction. 
     The operator wraps the second flexible member  1020   a  around the wheel of the pulley  1114  and attaches it to a free end of the retrieval flexible member  1140 , as shown in  FIG.  2 A . This attaches the first flexible member  1110   a  to the second flexible member  1120   a  and the retrieval flexible member  1140 . The remainder of the retrieval flexible member  1140  is stored in a container C on the deck at this point. The operator attaches the drag-producing device  1130  to the second flexible member  1120   a  near its attachment point to the retrieval flexible member  2110   c . The operator attaches the GPS receiver  1150  to the second flexible member  1120   a  between the pulley  1114  and the drag-producing device  1130 . The operator controls the second winch  1120  to retract the second flexible member  1120   a  and remove any slack in the second flexible member  1120   a , which draws the pulley  1114  and the GPS receiver  1150  toward one another. Once the slack is removed and the GPS receiver  1150  is at or near the pulley  1114 , the operator controls the second winch  1120  to maintain enough tension in the second flexible member  1120   a  to retain the GPS receiver  1150  at or near the pulley  1114 . 
     The operator controls the first and second winches such that the first and second flexible members  1110   a  and  1120   a  are respectively paid out from the first and second winches  1110  and  1120 . More specifically, in this example embodiment, the operator controls: (1) the first winch  1110  to actively payout the first flexible member  1110   a ; and (2) the second winch  1120  to maintain sufficient tension in the second flexible member  1120   a  to retain the GPS receiver  1150  at or near the pulley  1114 . As the first winch  1110  pays out the first flexible member  1110   a , it causes the second winch  1120  to backdrive and payout the second flexible member  1120   a  (since they&#39;re connected via the first flexible capture member attachment device  1112 ) while retaining the GPS receiver  1150  at or near the pulley  1114  (since the second winch  1120  maintains sufficient tension in the second flexible member  1120   a  and the retrieval flexible member  1140 ), as shown in  FIG.  2 B . In other embodiments, the operator simultaneously controls the first and second winches to payout the first and second flexible members, respectively, rather than relying on the first winch causing the second winch to backdrive to payout the second flexible member. 
     As the first and second flexible members  1110   a  and  1120   a  are paid out from the respective first and second winches  1110  and  1120 , the parasail P ascends via the wind and the continued motion of the ship S. This causes the retrieval flexible member  1140  to be paid out of the container C. 
     The operator controls the first and second winches  1110  and  1120  to stop paying out the first and second flexible members  1110   a  and  1120   a , respectively, once about 250 feet of the first flexible member extend between the first winch  1110  and the parasail P. More specifically, in this example embodiment, the operator controls the first winch  1110  to stop actively paying out the first flexible member  1110   a  once about 250 feet (or any other suitable amount) of the first flexible member  1110   a  extends between the first winch  1110  and the parasail P. This stops the first flexible member  1110   a  from causing the second winch  1120  to backdrive to pay out the second flexible member  1120   a.    
     At this point the operator controls the second winch  1120  to payout the second flexible member  1120   a  to enable gravity to pull the drag-producing device  1130  and the GPS receiver  1150  downward relative to the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114 , as shown in  FIG.  2 C . As this occurs, the drag-producing device  1130  begins producing drag via its interaction with the air. Specifically, the drag-producing device  1130  operates to straighten and tension the portion of the second flexible member  1120   a  extending between the pulley  1114  and the drag-producing device  1130 . 
     The operator controls the second winch  1120  to stop paying out the second flexible member  1120   a  once about 100 feet of the second flexible member  1120   a  extend between the pulley  1114  and the drag-producing device  1130 . 
     As shown in  FIG.  2 D , using the GPS coordinates received from the GPS receiver  1150 , the operator controls the fixed-wing aircraft  30  to contact and capture a portion of the second flexible member  1120   a  in a manner similar to that described in U.S. Pat. No. 6,264,140, the entire contents of which are incorporated herein by reference. After capture, the operator controls the second winch  1120  to retract the second flexible member  1120   a  such that the fixed-wing aircraft  30 , the drag-producing device  1130 , and the GPS receiver  1150  ascend toward the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114 . The operator controls the second winch  1120  such that the second flexible member  1120   a  stops retracting once the GPS receiver  1150  reaches the pulley  1114 , yet maintains enough tension in the second flexible member  1120   a  to retain the GPS receiver  1150  at the pulley  1114 . 
     The operator then controls the first and second winches  1110  and  1120  to respectively retract the first and second flexible members  1110   a  and  1120   a  until the fixed-wing aircraft  30  reaches the deck of the ship S, at which point the operator controls the winches to stop retracting. At this point, deck hands secure the fixed-wing aircraft  30  and detach the first flexible member attachment device  1112  from the first flexible member  1110   a , which disconnects the first flexible member  1110   a  from the second flexible member  1120   a  and the retrieval flexible member  1130 . The deck hands stow the fixed-wing aircraft  30 . The operator controls the first winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     2. One-Winch Embodiment 
     2.1 Parasail-Assisted Fixed-Wing Aircraft Launch System and Method 
       FIGS.  4 A- 4 E  are diagrammatic views showing another example parasail-assisted fixed-wing aircraft launch system and method of the present disclosure. In this example embodiment, the aircraft launch system includes the parasail P, the ballast B, the aircraft-launch apparatus  10 , the first winch  1110 , the first flexible member  1110   a , a second flexible member  2110   b , the first flexible member attachment device  1112 , the pulley  1114 , a flexible member guide  2116 , a second flexible member attachment device  2118 , and a feed-control device  2120 . 
     The parasail P, the ballast B, the aircraft-launch apparatus  10 , the first winch  1110 , the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114  are described above. 
     The second flexible member  2110   b  is a suitable rope or other similar flexible element. 
     The second flexible member attachment device  2118  is a suitable device configured to removably attach to the first flexible member  1110   a . In this example embodiment, the second flexible member attachment device  2118  includes an ascender that, once attached to the first flexible member  1110   a , can move along the first flexible member in one direction but not the other. This enables the operator to easily reposition the second flexible member attachment device  2118  (in one direction) along the first flexible member  1110   a  without removing the second flexible member attachment device  2118  from the first flexible member  1110   a . In other embodiments, the second flexible member attachment device is not configured to move along the second flexible member once attached to the first flexible member. A rope grab is one example of such a device. 
     The feed-control device  2120 , which is attached to the second flexible member attachment device  2118 , is a suitable device configured to receive a flexible member and to enable an operator to regulate whether and at what rate the flexible member can pass therethrough. A belay is one example of a feed-control device. 
     The flexible member guide  2116  is attachable to the first flexible member  1110   a  in any suitable manner and includes a guiding element—such as a closed loop—sized and shaped such that the second flexible member  2110   b  can pass therethrough. Other embodiments of the aircraft launch system do not include the flexible member guide. 
     One or more operators may use the components of the aircraft launch system to launch the fixed-wing aircraft  30  into free, wing-borne flight. A single operator is referred to below for brevity and clarity. 
     To prepare for launch, the operator attaches the first winch  1110  to a suitable area of the ship S in a suitable manner. In this example embodiment, the first winch  1110  is attached below the deck of the ship S. The operator attaches one end of the first flexible member  1110   a  to the drum of the first winch  1110  and controls the first winch  1110  to retract most of the first flexible member  1110   a . The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the first winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is generally evenly distributed between the left and right bridle sets of the parasail P. 
     In certain situations, the ship S may already be equipped with the first winch, the first flexible member, the parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to launch the fixed-wing aircraft into free, wing-borne flight. 
     The operator positions the fixed-wing aircraft  30  on the deck, such as on a launch-assist structure (not shown) that can be removably attached to the deck and that retains the fixed-wing aircraft  30  in a desired launch orientation. The operator attaches the hub module  100  of the aircraft-launch apparatus  10  to the fixed-wing aircraft  30  by: (1) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the release rotational position; (2) inserting the trailing edges of the wings of the fixed-wing aircraft  30  into the trailing edge receiving channels  6364   a  of the pivotable portions  6364  of the rear engagers  6360 ; (3) positioning the saddle  300  relative to the fixed-wing aircraft  30  such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  are adjacent the leading edges of the wings of the fixed-wing aircraft  30 ; (4) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the attached rotational position such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  contact the leading edges of the wings of the fixed-wing aircraft  30 ; and (5) operating the lock servo motor  6345  (either manually or remotely via the R/C controller) to rotate the lock arm  6346   a  into the front engager rotation-preventing rotational position so the locking extension  6346   a  on the end of the lock arm  6346  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . 
     At this point the fixed-wing aircraft  30  is attached to the saddle  300  because the front engager  6320  and the rear engagers  6360  engage the wings of the fixed-wing aircraft  30  therebetween. The pivotable portions  6364  of the rear engagers  6360  are rotationally positioned relative to the bodies  6362  of the rear engagers  6360  such that the trailing-edge engaging surfaces  6362   a  are not within the trailing-edge receiving channels of the pivotable portions  6364 . The positioning of the servo spacer  6344   b  and the fact that the locking extension  6346   a  is engaged to the front engager arm lock device  6342   a  of the front engager arm  6342  ensure the front engager servo motor  6341  cannot rotate the front engager  6320  from the attached rotational position to the release rotational position. This prevents undesired release of the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ). 
     After the hub module  100  is attached to the fixed-wing aircraft  30 , the operator attaches the front and rear landing gear modules  600   a  to  600   d  to their respective arm modules  400   a  to  400   d  and attaches and locks the arm modules  400   a  to  400   d  to the hub module  100  to complete assembly of the aircraft-launch apparatus  10 . 
     The operator starts up the engine of the fixed-wing aircraft  30  and controls the ship S to head into the wind and maintain this course throughout the launch process. The operator opens the parasail P and controls the first winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height, as shown in  FIG.  4 A . At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. 
     As shown in  FIG.  4 B , the operator attaches the first flexible member attachment device  1112  (and its attached pulley  1114 ) to the first flexible member  1110   a  a first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. The operator also attaches the second flexible member attachment device  2118  (and its attached feed-control device  2020 ) to the first flexible member  1110   a  between the first winch  1110  and the first flexible member attachment device  1112 . The operator also attaches the flexible member guide  2116  to the first flexible member  1110   a  between the first and second flexible member attachment devices  1112  and  2118 , respectively. 
     After attachment: (1) the first flexible member attachment device  1112  is movable along the first flexible member  1110   a  toward the parasail P but not in the opposite direction; (2) the second flexible member attachment device  2118  is movable along the first flexible member  1110   a  away from the parasail P but not in the opposite direction; and (3) the flexible member guide  2116  is not movable along the first flexible member  1110   a.    
     The operator feeds one end of the second flexible member  2110   b  through the feed-control device  2120  and through the flexible member guide  2116 , wraps the second flexible member  2110   b  around the wheel of the pulley  1114 , and attaches the second flexible member  2110   b  to the snag-prevention member  299  of the aircraft-launch apparatus  10 , as shown in  FIG.  4 B . This attaches the aircraft-launch apparatus  10  to the second winch  1120  and the first flexible member  1110   a  to the second flexible member  2110   b . At this point, the remainder of the second flexible member  2110   b  is stored in a container C on the deck. 
     While holding the feed-control device  2120 , the operator controls the first winch  1110  to actively payout the first flexible member  1110   a . As that occurs: (1) the paid out first flexible member  1110   a  travels through the second flexible member attachment device  2118  (which is held stationary relative to the ship S due to the operator holding the feed-control device  2120 ), which enables the parasail P to ascend via the wind and the continued motion of the ship S; and (2) the operator simultaneously controls the feed-control device  2120  to enable the second flexible member  2110   b  to payout from the container C. While doing so, the operator controls the feed-control device  2120  to maintain enough tension in the second flexible member  2110   b  to overcome the force of gravity and maintain the snag-prevention device  299  at or near the pulley  1114 . As the parasail P ascends, it lifts the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  off of the deck of the ship S (via the first flexible member attachment device  1112  and the pulley  1114 ). Once the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  are airborne, as the ship S travels into the wind, the rear landing gear of the aircraft-launch apparatus  10  act as vertical stabilizers (or fins) that ensure that the front of the aircraft-launch apparatus  10  and the nose of the attached fixed-wing aircraft  30  point generally into the wind. 
     The operator controls the first winch  1110  to stop actively paying out the first flexible member  1110   a  and controls the feed-control device  2120  to stop enabling the second flexible member  2110   b  to pay out of the container C once about 230 feet (or any other suitable amount) of the first flexible member  1110   a  extend between the first flexible member attachment device  1112  and the second flexible member attachment device  2118 , as shown in  FIG.  4 C . The operator controls the feed-control device  2120  to enable gravity to pull the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  downward relative to the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114 , as shown in  FIG.  4 D . While the pulley  1114  resists descent of the aircraft-launch apparatus  10  relative to the pulley  1114 , the aircraft-launch apparatus  10  is heavy enough such that gravity overcomes this resistive force. Once a stop device at the free end of the second flexible member  2110   b  engages the feed-control device  2120 , the aircraft-launch apparatus  10  has descended as far as it can relative to the pulley  1114  (since the stop device cannot fit through the feed-control device  2120 ). 
     The operator controls the first winch  1110  to payout the first flexible member  1110   a  until about 700 feet of the first flexible member  1110   a  extend between the winch  1110  and the parasail P. The operator controls the aircraft-launch apparatus  10  to release the fixed-wing aircraft  30  from the saddle  300 , as shown in  FIG.  4 E  and as explained above. 
     After the fixed-wing aircraft  30  is released into free, wing-borne flight, the operator controls the first winch  1110  to retract the first flexible member  1110   a  until the second flexible member attachment device  2118  reaches the operator. The operator grasps the second flexible member  2110   b  and removes the second flexible member attachment device  2118  from the first flexible member  1110   a . While holding the second flexible member  2110   b , the operator controls the first winch  1110  to payout the first flexible member  1110   a  such that the parasail P ascends. Once the snag-prevention member  299  reaches the one-way pulley, the operator controls the first winch  1110  to retract the first flexible member  1110   a . As this occurs, the operator maintains sufficient tension in the second flexible member  2110   b  to maintain the snag-prevention device  299  at or near the pulley  1114 . 
     Once the aircraft-launch apparatus  10  reaches the deck of the ship S, the operator controls the first winch  1110  to stop retracting. At this point, deck hands secure the aircraft-launch apparatus  10  and detach the first flexible member attachment device  1112  from the first flexible member  1110   a , which disconnects the first flexible member  1110   a  from the second flexible member  1120   a . The deck hands disassemble and stow the aircraft-launch apparatus  10 . The operator controls the first winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     In certain embodiments, the aircraft launch system includes a compliant structure, such as a trampoline, to aid in the launch process. In these embodiments, the compliant structure is erected over part of the deck of the ship (or other moving object), and the fixed-wing aircraft  30  is positioned on the compliant structure before (or after) the aircraft-launch apparatus  10  is attached to the fixed-wing aircraft  30 . The compliant structure acts as a damper that dampens forces that would otherwise be exerted on the aircraft-launch apparatus  10  and the fixed-wing aircraft  30  to be damaged as the ship S moves (especially in rough seas), which reduces the potential for damage to these apparatuses. 
     In other embodiments in which the saddle is that described in U.S. Patent Application Publication No. 2017/0158318, the fixed-wing aircraft launch method incorporates the procedure for releasing the fixed-wing aircraft from the saddle described in U.S. Patent Application Publication No. 2017/0158318. 
     In another embodiment, the aircraft launch system includes a receptacle attached to the pulley and a locking element attached to the end of the second flexible member near the aircraft launch apparatus. The receptacle is sized to receive the locking element and is configured to engage the locking element responsive to receiving the locking element to retain the locking element therein. The receptacle is also configured to release the locking element responsive to the operator tugging the second flexible member. 
     In operation, before controlling the first winch to payout the first flexible capture member to enable the parasail to ascend, the operator ensures the locking element is received in the receptacle and that the receptacle engages the locking element to retain the locking element therein. This ensures the aircraft launch apparatus is positioned near the pulley during this part of the launch process. Once the operator desires the aircraft launch apparatus to descent, the operator tugs on the second flexible member to cause the receptacle to disengage the locking element, thereby causing the aircraft launch apparatus to descend. After release of the fixed-wing aircraft, the operator controls the second winch to retract the second flexible member until the locking element is received in the receptacle such that the receptacle retains the locking element therein. 
     2.2 Parasail-Assisted Fixed-Wing Aircraft Retrieval System and Method 
       FIGS.  5 A- 5 E  are diagrammatic views showing another example parasail-assisted fixed-wing aircraft retrieval system and method of the present disclosure. In this example embodiment, the aircraft retrieval system includes the parasail P, the ballast B, the first winch  1110 , the first flexible member  1110   a , the second flexible member  2110   b , a third flexible member  2110   c , the first flexible member attachment device  1112 , the pulley  1114 , the second flexible member attachment device  2118 , the feed-control device  2120 , the drag-producing device  1130 , and the GPS receiver  1150 . These components are described above. 
     To prepare for retrieval, the operator attaches the first winch  1110  to a suitable area of the ship S in a suitable manner. In this example embodiment, the first winch  1110  is attached below the deck of the ship S. The operator attaches one end of the first flexible member  1110   a  to the drum of the first winch  1110  and controls the first winch  1110  to retract most of the first flexible member  1110   a . The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the first winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is generally evenly distributed between the left and right bridle sets of the parasail P. 
     In certain situations, the ship may already be equipped with the first winch, the first flexible member, the parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to retrieve the fixed-wing aircraft from free, wing-borne flight. 
     The operator controls the ship S to head into the wind and maintain this course throughout the retrieval process. The operator opens the parasail P and controls the first winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height, as shown in  FIG.  5 A . At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. 
     As shown in  FIG.  5 B , the operator attaches the first flexible member attachment device  1112  (and its attached pulley  1114 ) to the first flexible member  1110   a  a first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. The operator also attaches the second flexible member attachment device  2118  (and its attached feed-control device  2020 ) to the first flexible member  1110   a  between the first winch  1110  and the first flexible member attachment device  1112 . After attachment: (1) the first flexible member attachment device  1112  is movable along the first flexible member  1110   a  toward the parasail P but not in the opposite direction; and (2) the second flexible member attachment device  2118  is movable along the first flexible member  1110   a  away from the parasail P but not in the opposite direction. 
     The operator feeds one end of the second flexible member  2110   b  through the feed-control device  2120  and through the flexible member guide  2116 , wraps the second flexible member  2110   b  around the wheel of the pulley  1114 , and attaches the second flexible member  2110   b  to a free end of the third flexible member  2110   c , as shown in  FIG.  5 B . This attaches the first flexible member  1110   a  to the second flexible member  2110   b  and to the third flexible member  2110   c . At this point, the remainder of the second flexible member  2110   b  is stored in a container C 1  on the deck and the remainder of the third flexible member  2110   c  is stored in a container C 2  on the deck. The operator attaches the drag-producing device  1130  to the second flexible member  2110   b  near its attachment point to the third flexible member  2110   c . The operator attaches the GPS receiver  1150  to the second flexible member  2110   b  between the pulley  1114  and the drag-producing device  1130 . 
     While holding the feed-control device  2120 , the operator controls the first winch  1110  to actively payout the first flexible member  1110   a . As that occurs: (1) the paid out first flexible member  1110   a  travels through the second flexible member attachment device  2118  (which is held stationary relative to the ship S due to the operator holding the feed-control device  2120 ), which enables the parasail P to ascend via the wind and the continued motion of the ship S; (2) the operator simultaneously controls the feed-control device  2120  to enable the second flexible member  2110   b  to payout from the container C 1  and the third flexible member  2110   c  to payout from the container C 2  (since it&#39;s connected to the second flexible member  2110   b ). While doing so, the operator controls the feed-control device  2120  to maintain enough tension in the second flexible member  2110   b  to overcome the force of gravity and maintain the GPS receiver  1150  at or near the pulley  1114  and also maintains some amount of tension in the third flexible member  2110   c . As the parasail P ascends, it lifts the GPS receiver  1150  and the drag-producing device  1130  off of the deck of the ship S (via the first flexible member attachment device  1112  and the pulley  1114 ). 
     The operator controls the first winch  1110  to stop actively paying out the first flexible member  1110   a  and controls the feed-control device  2120  to stop enabling the second flexible member  2110   b  to pay out of the container C 1  once about 200 feet (or any other suitable amount) of the first flexible member  1110   a  extend between the first flexible member attachment device  1112  and the second flexible member attachment device  2118 , as shown in  FIG.  5 C . The operator controls the feed-control device  2120  to enable gravity to pull the GPS receiver  1150  and the drag-producing device  1130  downward relative to the first flexible member  1110   a , the first flexible member attachment device  1112 , and the pulley  1114 , as shown in  FIG.  5 D . While the pulley  1114  resists descent of the GPS receiver  1150  and the drag-producing device  1130  relative to the pulley  1114 , the aircraft-launch apparatus  10  is heavy enough such that gravity overcomes this resistive force. Once a stop device at the free end of the second flexible member  2110   b  engages the feed-control device  2120 , the GPS receiver  1150  and the drag-producing device  1130  have descended as far as they can relative to the pulley  1114  (since the stop device cannot fit through the feed-control device  2120 ). As this occurs, the drag-producing device  1130  begins producing drag via its interaction with the air. Specifically, the drag-producing device  1130  operates to straighten and tension the portion of the second flexible member  2110   b  extending between the pulley  1114  and the drag-producing device  1130 . 
     As shown in  FIG.  5 E , using the GPS coordinates received from the GPS receiver  1150 , the operator controls the fixed-wing aircraft  30  to contact and capture a portion of the second flexible member  2110   b  in a manner similar to that described in U.S. Pat. No. 6,264,140, the entire contents of which are incorporated herein by reference. After capture, the operator grasps the second flexible member attachment device  2118  and, while holding the second flexible member attachment device  2118 , controls the first winch  1110  to payout the first flexible member  1110   a . The paid out first flexible member  1110   a  travels through the second flexible member attachment device  2118  (which is held stationary relative to the ship S), which enables the parasail P to ascend via the wind and the continued motion of the ship S. This causes captured fixed-wing aircraft  30 , the GPS receiver  1150 , and the drag-producing device  1130  to ascend toward the pulley  1114 . 
     Once the captured fixed-wing aircraft reaches the pulley  1114 , the operator controls the first winch  1110  to retract the first flexible member  1110   a . As this occurs, the operator maintains sufficient tension in the second flexible member  2110   b  to maintain the captured fixed-wing aircraft  30  at or near the pulley  1114  and maintains sufficient tension in the third flexible member  2110   c  to prevent substantial movement of the fixed-wing aircraft  30 . Once the fixed-wing aircraft  30  reaches the deck of the ship S, the operator controls the first winch  1110  to stop retracting. At this point, deck hands secure the fixed-wing aircraft  30  and detach the first and second flexible member attachment devices  1112  and  2118  from the first flexible member  1110   a , which disconnects the first flexible member  1110   a  from the second flexible member  2110   b  and the third flexible member  2110   c . The operator controls the first winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     3. Winch and Hoist Embodiment 
     3.1 Parasail-Assisted Fixed-Wing Aircraft Launch System and Method 
       FIGS.  6 A to  6 C  are diagrammatic views showing another example parasail-assisted fixed-wing aircraft launch system and method of the present disclosure. In this example embodiment, the aircraft launch system includes the parasail P, the ballast B, the aircraft-launch apparatus  10 , the winch  1110 , the first flexible member  1110   a , a hoist  3120 , and a second flexible member  3120   b.    
     The parasail P, the ballast B, the aircraft-launch apparatus  10 , the winch  1110 , and the first flexible member  1110   a  are described above. 
     The hoist  3120  includes a winch or other mechanism configured to extend and/or retract the second flexible member  3120   b . The second flexible member  3120   b  includes a suitable rope or other similar flexible element. 
     The hoist  3120  includes a suitable device configured to removably attach to the first flexible member  1110   a . In this example embodiment, the hoist  3120  includes one or more locking members or connecting members that attach the hoist  3120  to the first flexible member  1110   a . This enables the operator to easily extend or retract the hoist  3120  from the ship S by controlling the winch  1110  and enabling the parasail P to ascend and descend. It should be noted that once the hoist  3120  is attached to the first flexible member  1110   a , it may remain a fixed distance from the ballast B and/or parasail P. In other words, once the hoist  3120  has been attached to the first flexible member  1110   a , the hoist  3120  may rise upward along with the parasail P as the winch  1110  lets out more of the first flexible member  110   a .  FIGS.  7 A and  7 B  illustrate this feature. This example maintains the benefits of keeping the launching aircraft clear of the area during parasail launch and landing. Further, the hoist is affixed to the first flexible member, so there is no need to synchronize parallel lengths of tether during the critical phases of the launch sequence. 
       FIG.  7 A  shows the first flexible member  1110   a  comprising a first segment  7000  between the ballast B and the hoist  3120 , and a second segment  7002  between the hoist  3120  and the winch  1110 . Once the hoist  3120  is attached to the first flexible member, the length of the first segment  7000  will not change. 
       FIG.  7 B  shows that the parasail has been let out and has risen into the air. The length of segment  7000  remains unchanged, and thus the hoist  3120  has risen along with the parasail.  FIG.  7 B  shows that the length of segment between the hoist  3120  and the winch  1110  has increased. This is segment  7004  in  FIG.  7 B . Segment  7004  is longer than segment  7002 . Consequently, the hoist  3120  and aircraft have departed the aft deck of the ship S. 
     Referring back to  FIGS.  6 A to  6 C , one or more operators may use the components of the aircraft launch system to launch the fixed-wing aircraft  30  into free, wing-borne flight. A single operator is referred to below for brevity and clarity. 
     To prepare for launch, the operator attaches the winch  1110  to a suitable area of the ship S in a suitable manner. In this example embodiment, the winch  1110  is attached to the deck of the ship S. The operator attaches one end of the first flexible member  1110   a  to the drum of the winch  1110  and controls the winch  1110  to retract most of the first flexible member  1110   a . The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the first winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is distributed between the left and right bridle sets of the parasail P. The operator may deliberately distribute the mass unevenly, to force the parasail P to follow the ship off-center, thus maximizing clearance between the flexible members and the launching aircraft during release and climb-out. 
     In certain situations, the ship S may already be equipped with the winch, the first flexible member, the parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to launch the fixed-wing aircraft into free, wing-borne flight. 
     The operator opens the parasail P, exposing it to the headwind, and controls the winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height, as shown in  FIG.  6 A . At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the first winch  1110  and the parasail P. 
     The operator positions the fixed-wing aircraft  30  on the deck, such as on a launch-assist structure (not shown) that can be removably attached to the deck and that retains the fixed-wing aircraft  30  in a desired launch orientation. The operator attaches the hub module  100  of the aircraft-launch apparatus  10  to the fixed-wing aircraft  30  by: (1) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the release rotational position; (2) inserting the trailing edges of the wings of the fixed-wing aircraft  30  into the trailing edge receiving channels  6364   a  of the pivotable portions  6364  of the rear engagers  6360 ; (3) positioning the saddle  300  relative to the fixed-wing aircraft  30  such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  are adjacent the leading edges of the wings of the fixed-wing aircraft  30 ; (4) operating the front engager servo motor  6341  (either manually or remotely via the R/C controller) to rotate the front engager  6320  to the attached rotational position such that the leading edge engaging surfaces  6323   b  and  6326   b  of the front engager  6320  contact the leading edges of the wings of the fixed-wing aircraft  30 ; and (5) operating the lock servo motor  6345  (either manually or remotely via the R/C controller) to rotate the lock arm  6346   a  into the front engager rotation-preventing rotational position so the locking extension  6346   a  on the end of the lock arm  6346  engages the front engager arm lock device  6342   a  of the front engager arm  6342 . 
     At this point the fixed-wing aircraft  30  is attached to the saddle  300  because the front engager  6320  and the rear engagers  6360  engage the wings of the fixed-wing aircraft  30  therebetween. The pivotable portions  6364  of the rear engagers  6360  are rotationally positioned relative to the bodies  6362  of the rear engagers  6360  such that the trailing-edge engaging surfaces  6362   a  are not within the trailing-edge receiving channels of the pivotable portions  6364 . The positioning of the servo spacer  6344   b  and the fact that the locking extension  6346   a  is engaged to the front engager arm lock device  6342   a  of the front engager arm  6342  ensure the front engager servo motor  6341  cannot rotate the front engager  6320  from the attached rotational position to the release rotational position. This prevents undesired release of the fixed-wing aircraft  30  from the saddle  300  (and the aircraft-launch apparatus  10 ). 
     After the hub module  100  is attached to the fixed-wing aircraft  30 , the operator attaches the front and rear landing gear modules  600   a  to  600   d  to their respective arm modules  400   a  to  400   d  and attaches and locks the arm modules  400   a  to  400   d  to the hub module  100  to complete assembly of the aircraft-launch apparatus  10 . 
     The operator starts up the engine of the fixed-wing aircraft  30  and controls the ship S to head into the wind and maintains this course throughout the launch process. As shown in  FIG.  6 A , the operator attaches the hoist  3120  to the first flexible member  1110   a  a first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. 
     The operator attaches one end of the second flexible member  3120   b  to the snag-prevention member  299  of the aircraft-launch apparatus  10 , as shown in  FIG.  6 B . This attaches the aircraft-launch apparatus  10  to the hoist  3120 , and the first flexible member  1110   a  to the second flexible member  2110   b . At this point, the remainder of the second flexible member  2110   b  is stored in the hoist  3120 . 
     The operator controls the winch  1110  to actively payout the first flexible member  1110   a . As that occurs, the paid out first flexible member  1110   a  enables the parasail P to ascend along with the aircraft-launch apparatus  10 . While ascending, the hoist  3120  maintains enough tension in the second flexible member  3120   b  to overcome the force of gravity and maintain the aircraft-launch apparatus at or near the hoist  3120 . As the parasail P ascends, it lifts the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  off of the deck of the ship S. Once the aircraft-launch apparatus  10  and the attached fixed-wing aircraft  30  are airborne, as the ship S travels into the wind, the rear landing gear or fins of the aircraft-launch apparatus  10  act as vertical stabilizers ensuring the front of the aircraft-launch apparatus  10  and the nose of the attached fixed-wing aircraft  30  point generally into the relative wind. 
     The operator controls the winch  1110  to payout the first flexible member  1110   a  to a predetermined height. In some examples, about 700 feet of the first flexible member  1110   a  extends between the winch  1110  and the parasail P. The operator controls the hoist to lower the aircraft launch apparatus to about 100 feet below the first flexible member. Then the operator controls the aircraft-launch apparatus  10  to release the fixed-wing aircraft  30  from the saddle  300 , as shown in  FIG.  6 C  and as explained above. 
     After the fixed-wing aircraft  30  is released into free, wing-borne flight, the operator controls the hoist to elevate the aircraft launch apparatus to the first flexible member, and the winch  1110  to retract the first flexible member  1110   a  until the hoist  3120  and the aircraft-launch apparatus  10  reach the operator. The operator grasps the aircraft-launch apparatus  10  and the hoist  3120  and removes them from the first flexible member  1110   a . The deck hands disassemble and stow the aircraft-launch apparatus  10 . The operator controls the winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     In certain embodiments, the aircraft launch system includes a compliant structure, such as a trampoline, to aid in the launch process. In these embodiments, the compliant structure is erected over part of the deck of the ship (or other moving object), and the fixed-wing aircraft  30  is positioned on the compliant structure before (or after) the aircraft-launch apparatus  10  is attached to the fixed-wing aircraft  30 . The compliant structure acts as a damper that dampens forces that would otherwise be exerted on the aircraft-launch apparatus  10  and the fixed-wing aircraft  30  to be damaged as the ship S moves (especially in rough seas), which reduces the potential for damage to these apparatuses. 
     In other embodiments in which the saddle is that described in U.S. Patent Application Publication No. 2017/0158318, the fixed-wing aircraft launch method incorporates the procedure for releasing the fixed-wing aircraft from the saddle described in U.S. Patent Application Publication No. 2017/0158318. 
     3.2 Parasail-Assisted Fixed-Wing Aircraft Retrieval System and Method 
       FIGS.  6 D- 6 G  are diagrammatic views showing another example parasail-assisted fixed-wing aircraft retrieval system and method of the present disclosure. In this example embodiment, the aircraft retrieval system includes the parasail P, the ballast B, the winch  1110 , the first flexible member  1110   a , the hoist  3120 , the second flexible member  3120   b , a reel  3130 , a third flexible member  3130   c , and the GPS receiver  3150 . Some of these components are described above. 
     To prepare for retrieval, the operator attaches the winch  1110  to a suitable area of the ship S in a suitable manner. In this example embodiment, the winch  1110  is attached to the deck of the ship S. The operator attaches one end of the first flexible member  1110   a  to the drum of the winch  1110  and controls the winch  1110  to retract most of the first flexible member  1110   a . The operator attaches the free end of the first flexible member  1110   a  to the left and right bridle sets of the parasail P. This attaches the parasail P to the winch  1110 . The operator also attaches the ballast B to the left and right bridle sets of the parasail P such that the mass of the ballast B is distributed between the left and right bridle sets of the parasail P. 
     In certain situations, the ship may already be equipped with the winch, the first flexible member, the parasail, and/or the ballast. In these situations, the operator need not take the above-described steps, and instead leverages the equipment already on the moving object (along with the additional components described above) to retrieve the fixed-wing aircraft from free, wing-borne flight. 
     The operator controls the ship S to head into the wind and maintains this course throughout the retrieval process. The operator opens the parasail P and controls the winch  1110  to payout the first flexible member  1110   a  until the parasail P reaches a stable flying height, as shown in  FIG.  6 D . At this point in this example embodiment, about 50-100 feet of the first flexible member  1110   a  extend between the winch  1110  and the parasail P. 
     As shown in  FIG.  6 D , the operator attaches the hoist  3120  to the first flexible member  1110   a  a first distance from the parasail P. In this example embodiment, the first distance is about 50-100 feet, though it may be any suitable distance in other embodiments. 
     The operator attaches the second flexible member  3120   b  to a free end of the third flexible member  3130   c , as shown in  FIG.  6 D . This attaches the first flexible member  1110   a  to the second flexible member  3120   b  and to the third flexible member  3130   c . At this point, the remainder of the second flexible member  3120   b  is stored in the hoist  3120 , and the remainder of the third flexible member  3130   c  is stored on the reel  3130 . The operator may attach a drag-producing device to the second flexible member  3120   b  near its attachment point to the third flexible member  3130   c . The operator attaches the GPS receiver  3150  to the second flexible member  3120   b , also near this location. Alternatively, the GPS receiver may be attached at the hoist location, but the location described above may be preferred when accuracy and clearance to the first flexible member is important. 
     The operator controls the winch  1110  to actively payout the first flexible member  1110   a . As that occurs, the operator allows the reel  3130  to pay-out the third flexible member  3130   c  from the reel  3130 . While doing so, the operator controls the hoist  3120  to maintain enough tension in the second flexible member  3120   b  to overcome the force of gravity and maintain the GPS receiver  3150  at or near hoist  3120  and also maintains some amount of tension in the third flexible member  3130   c . As the parasail P ascends, it lifts the GPS receiver  3150  and any attached drag-producing device off of the deck of the ship S. 
     The operator controls the winch  1110  to stop actively paying out the first flexible member  1110   a  and controls the reel  3130  to stop enabling the third flexible member  3130   c  to pay out of the reel  3130  once a sufficient length of the first flexible member  1110   a  extends from the winch  1110  to the parasail P, as shown in  FIG.  6 E . The operator controls the hoist  3120  to enable gravity and aerodynamic drag to pull the GPS receiver  3150  downward relative to the first flexible member  1110   a  as shown in  FIG.  6 E . 
     As shown in  FIG.  6 F , using the GPS coordinates received from the GPS receiver  3150 , the operator controls the fixed-wing aircraft  30  to contact and capture a portion of the second flexible member  3120   b  in a manner similar to that described in U.S. Pat. No. 6,264,140, the entire contents of which are incorporated herein by reference. After capture, the operator controls the hoist  3120  to retract the second flexible member  3120 B into the hoist  3120 , and raise the captured fixed-wing aircraft  30  toward the first flexible member  1110   a.    
     Once the captured fixed-wing aircraft reaches the hoist  3120 , the operator controls the winch  1110  to retract the first flexible member  1110   a . As this occurs, the operator maintains sufficient tension in the third flexible member  3130   c  using the reel  3130  to keep the GPS receiver from dipping into the water. Once the fixed-wing aircraft  30  reaches the deck of the ship S, the operator controls the winch  1110  to stop retracting. At this point, deck hands secure the fixed-wing aircraft  30  and detach the hoist from the first flexible member  1110   a , which disconnects the first flexible member  1110   a  from the second flexible member  3120   b  The operator then controls the winch  1110  to retract the remainder of the first flexible member  1110   a  such that the deck hands can collapse and stow the parasail P and the ballast B. 
     In some embodiments, usage of the concepts described herein may take the form of a primary or host ship and its tender. For example, the host ship may be a larger ship configured to store the secondary ship as its tender. The tender in turn may be a rigid hulled inflatable boat (RHIB) specially configured for launch and retrieval of the aircraft. As such, the tender may be configured to store specialized hardware such as the parasail winch or winches, parasail launching mast, aircraft launch cradle, engine cooling system for the aircraft, and engine starter for the aircraft. Further, the tender may have an enlarged deck for use in connection with the launching and retrieval of the aircraft as described herein. 
     In some examples, the hardware may also be engaged with suitable quick disconnect fittings to the tender. This can allow quick swapping of the hardware with seats or other components when not in use. 
     Various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. These changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is intended that such changes and modifications be covered by the appended claims.