Facilitating high-degree flow turning of thrusted air

Abstract

Aspects described herein relate to flow turning across an aircraft wing. An aircraft may include propulsors configured to propel an airflow across the upper surface of the aircraft wing. Due to the Coandă effect, the airflow may adhere to the upper surface of the aircraft wing. A movable flap may be attached to a trailing edge of the aircraft wing. The flap may be configured to rotate between retracted and rotated positions. The flap may be configured to rotate up to and beyond 90 degrees. During rotation, another flap may pivot to a deployed position to provide a continuous surface between a trailing edge of the aircraft wing and a leading edge of the moveable flap for the airflow to adhere to, which facilitates turning the flow of air across the aircraft wing.

Description

FACILITATING HIGH-DEGREE FLOW TURNING OF THRUSTED AIRCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application 63 / 730,310 titled “JETFOIL” filed on December 10, 2024, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosures generally relate to thrust vectoring, and more particularly to turning a flow of air propelled across an upper surface of an aircraft wing having embedded propulsors.BACKGROUND

[0003] Researchers have observed that a fluid such as an airflow tends to stay attached to a curved or inclined surface. This effect has been termed the Coanda effect after an early researcher that recognized and applied this phenomenon. More particularly, due to the airflow dragging (entraining) some of the surrounding flow of air on one side of the airflow but not the other, a region of low pressure arises between the airflow and the surface. This region of low pressure results in a region of higher pressure on the opposite side of the airflow, which may result in the airflow adhering to and following the surface.SUMMARY

[0004] The following presents a simplified summary of various aspects described herein. This summary is not an extensive overview and is not intended to identify key or critical elements or to delineate the scope of any claim. The following summary merely presents some concepts in a simplified form as an introductory prelude to the more detailed description provided below.

[0005] Aspects described herein relate to thrust vectoring, and more particularly to turning the flow of air propelled across an upper surface of an aircraft wing. High-degree flow turning includes turning the flow of thrusted air up to, and even beyond, 90 degrees. To achieve such a high-degree of flow turning, the disclosures herein describe a wing having rotating flap positioned at the trailing edge of the wing and configured to rotate between a retracted position and a rotated position. The inventors have discovered that successful flow turning to such extreme degrees depends on the flow of thrusted air remaining attached to the upper surface ofthe rotating flap during rotation. Discontinuities such as gaps between the upper surface of the wing and the upper surface of the rotating flap, or gaps between adjacent rotating flaps, can cause the flow of thrusted air to detach from the upper surface and fail to turn with the rotating flap during rotation. The inventors have also discovered that maintaining a smooth transition from the upper surface of the wing to the upper surface of the rotating flap throughout the rotation also facilitates the flow of thrusted air remaining attached to the upper surface of the aft flap and turning with the aft flap during the rotation.

[0006] The disclosures herein thus describe features of a flow turning control assembly that facilitate a flow of air propelled across an upper surface of an aircraft wing to remain attached to an upper surface of a rotating flap as it rotates to a rotated position. Such features include a pivotable flap that is deployed during the rotation to provide a surface that extends between the trailing edge of the wing and the leading edge of the rotating flap for the flow of thrusted air to remain attached to as the rotating flap moves between the retracted position and the rotated position. Deployment of the pivotable flap during rotation thus avoids any discontinuities (e.g., gaps) forming between the trailing edge of the wing and the leading edge of the rotating flap thereby providing a surface for the flow of thrusted air to remain attached to and consequently turn with as the aft flap rotates to a rotated position.

[0007] These features, along with many others, are discussed by way of example in greater detail below.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which:

[0009] Figure 1 illustrates a top view of an example of an aircraft wing with an array of embedded propulsors with a rotating flap at a retracted position in accordance with aspects described herein;

[0010] Figure 2A illustrates a top view of the example aircraft wing of Figure 1 with the rotating flap at a rotated position in accordance with aspects described herein;

[0011] Figure 2B illustrates a bottom view of the example aircraft wing of Figure 1 with the rotating flap at a rotated position and the pivoting flap at a deployed position in accordance with aspects described herein;

[0012] Figure 3A illustrates an example of a flow turning control assembly with a flap assembly at a retracted position in accordance with aspects described herein;

[0013] Figure 3B illustrates the example flow turning control assembly of Figure 3A with the flap assembly at a rotated position in accordance with aspects described herein;

[0014] Figure 4 illustrates a cross-sectional side view of an example of an aircraft wing with an embedded propulsor and a flow turning control assembly in accordance with aspects described herein;

[0015] Figure 5A illustrates a cross-sectional side view of an example of a flap assembly with a pivoting flap at a stowed position in accordance with aspects described herein;

[0016] Figure 5B illustrates a cross-sectional side view of the example flap assembly of Figure 5 A with the pivoting flap at a deployed position in accordance with aspects described herein;

[0017] Figure 6 illustrates an example of a pivoting flap in accordance with aspects described herein;

[0018] Figure 7A illustrates a cross-sectional side view of an example flow turning control assembly with a flap assembly at a retracted position and the pivoting flap at a stowed position in accordance with aspects described herein;

[0019] Figure 7B illustrates a cross-sectional side view of the example flow turning control assembly of Figure 7A with the flap assembly at a rotated position and the pivoting flap at a deployed position in accordance with aspects described herein;

[0020] Figure 7C illustrates a perspective view of the flow turning control assembly of Figure 7B with the flap assembly at the rotated position and the pivoting flap at a deployed position in accordance with aspects described herein;

[0021] Figure 8A illustrates a top perspective view of an example of a rear flap of a flap assembly in accordance with aspects described herein;

[0022] Figure 8B illustrates a bottom perspective view of the example rear flap of Figure 8A in accordance with aspects described herein;

[0023] Figure 9A illustrates a top perspective view of an example of a forward flap panel of a flap assembly in accordance with aspects described herein;

[0024] Figure 9B illustrates a bottom perspective view of the example forward flap panel of Figure 9A in accordance with aspects described herein;

[0025] Figure 10 illustrates a side view of an example side brace of a drive assembly in accordance with aspects described herein;

[0026] Figure 11A illustrates a top perspective view of portions of an example flap assembly and portions of an example drive assembly in an assembled configuration in accordance with aspects described herein;

[0027] Figure 1 IB illustrates a bottom rear perspective view of the example flap assembly of Figure 11A with example aft couplers for a lower skin panel in accordance with aspects described herein;

[0028] Figure 12A illustrates a top perspective view of an example of a lower skin panel of flap assembly in accordance with aspects described herein;

[0029] Figure 12B illustrates a top perspective view of the example lower skin panel of Figure 12A, portions of an example flap assembly, and portions of an example drive assembly in an assembled configuration in accordance with aspects described herein;

[0030] Figure 12C illustrates a top perspective view of a pair of geared tracks of an example drive system in accordance with aspects described herein;

[0031] Figure 13A illustrates a rear perspective view of a portion of an example drive assembly in accordance with aspects described herein;

[0032] Figure 13B illustrates a top perspective view of the example drive assembly of Figure 13A and portions of an example flap assembly in an assembled configuration in accordance with aspects described herein;

[0033] Figures 14A-B illustrate the turning radius of an example flap assembly in accordance with aspects described herein;

[0034] Figure 15A illustrates a cross-sectional rear perspective view of an example aircraft wing with an alternative example of a flap assembly in accordance with aspects described herein;

[0035] Figure 15B illustrates a rear perspective view of the example aircraft wing of Figure 15A with the alternative example flap assembly at a rotated positioned in accordance with aspects described herein;

[0036] Figure 16 illustrates an example of an aerodynamic stator in accordance with aspects described herein;

[0037] Figure 17 illustrates a schematic view of an example flow turning control system in accordance with aspects described herein;

[0038] Figure 18A illustrates a flowchart of example method steps for flow turning control in accordance with aspects described herein;

[0039] Figure 18B illustrates another flowchart of example method steps for flow turning control in accordance with aspects described herein;

[0040] Figure 19 illustrates a block diagram of example components of a microcontroller or a computing device in accordance with aspects described herein.DETAILED DESCRIPTION

[0041] In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration various examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and implemented whereby structural and functional modifications may be made without departing from the scope and spirit of the present disclosure. Further, headings within this disclosure should not be considered as limiting aspects of the disclosure. Those skilled in the art with the benefit of this disclosure will appreciate that the examples are not limited to the headings.

[0042] Aspects of the disclosure are capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Rather, the phrases and terms used herein are to be given their broadest interpretationand meaning. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.

[0043] By way of introduction, aspects of the present disclosure related to thrust vectoring in an aircraft. Examples of aircraft include manned aircraft, unmanned aircraft, and drones. Aircraft as described herein may be configured for one or more of conventional take-off and landing (CTOL), short take-off and landing (STOL), or vertical take-off and landing (VTOL). Thrust vectoring as described herein includes turning a flow of thrusted air up to 90 degrees and beyond, including up to 180 degrees. Flow turning between 90-180° may be described for convenience as high-degree flow turning. The high-degree flow turning described herein may be achieved in aircraft having wings with one or more embedded propulsors. Propulsors embedded in the wing of an aircraft also may be referred to as integrated propulsors due to their integration into the geometry of the wing as opposed to being simply attached to an upper surface or lower surface of the wing. Such propulsors may be ducted and thus may be referred to as ducted propulsors. Aircraft wings with embedded propulsors thus may be referred to as ducted wings. Examples of embedded propulsors, ducted wings, and aircraft with ducted wings are described in commonly owned U.S. Patent Application No. 18 / 208,181 titled “Ducted Wing with Flaps,” U.S. Patent Application No. 18 / 814,250 titled “Exhaust Area Flow Turning Control,” and U.S. Patent Application No. 18 / 967,410 titled “Uniform Exhaust Sheet and Flow Turning Control,” each of which are incorporated by reference herein in their entirety.

[0044] The disclosures herein describe features of a flow turning control assembly that facilitates high-degree flow turning in aircraft having ducted wings. During operation, an array of propulsors embedded in the ducted wing propel a flow of air across the upper surface of the ducted wing. The thrusted air from individual propulsors may combine at an exhaust outlet defined by the array of propulsors to form a uniform sheet of thrusted air extending across the span of the ducted wing. A control surface positioned at the trailing edge of the ducted wing may move to control the flow of the uniform sheet of thrusted air. The control surface described herein is a flap configured to rotate between a retracted position at the trailing edge of the wing and a rotated position. As the flap rotates between the retracted position and the rotated position, the uniform sheet of thrusted air remains attached to the upper surface of the flap and thus follows the curvature of the flap during rotation achieving thrust vectoring that matches the degree of rotation. In some embodiments, the rotating flap described herein may rotate upto 90 degrees thus turning the uniform sheet of thrusted air up to 90 degrees as well. In other embodiments, a rotating flap may rotate more than 90 degrees. For example, in some embodiments, a rotating flap may rotate at least or up to, for example, 100 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 170 degrees, and / or 175 degrees. Those skilled in the art with the benefit of this disclosure will understand that rotating flaps disclosed herein may be positioned such as to turn the uniform sheet of thrusted air up to 180 degrees and that any angle between 0-180 degrees is within the scope of the disclosures.

[0045] Due to the geometries of the ducted wing and the flow turning control assembly, the length of the rotating flap may be limited. For example, as described herein, the flow turning control assembly may be configured to rotate the flap along a circular path with a relatively tight turning radius. Given these design constraints, the length of the flap may not be sufficient to provide a continuous surface for the uniform sheet of thrusted air to remain attached to when the flap is fully rotated. To ensure no discontinuities (e.g., gaps) form between the trailing edge of the ducted wing and the leading edge of the rotating flap form when rotating the flap to a rotated position, a pivotable flap is deployed during rotation to provide a surface that extends from the trailing edge of the ducted wing to the leading edge of the rotating flap. At the retracted position, the leading edge of the rotating flap may overlap the trailing edge of the ducted wing. As the rotating flap rotates away from the trailing edge of the ducted wing, the pivoting flap may be deployed before the rotating flap rotates to a fully rotated position. More particularly, the pivoting flap may be deployed during the rotation before the leading edge of the rotating flap no longer overlaps the trailing edge of the ducted wing (i.e., before the leading edge of the rotating flap is spatially separated from the trailing edge of the ducted wing). By deploying the pivoting flap during the rotation in this manner, the pivoting flap ensures a surface is present for the uniform sheet of thrusted air to remain attached to and turn with rotating flap. In this way, the pivoting flap facilitates high-degree flow turning of a flow of thrusted air across the span of a ducted wing.

[0046] It should be appreciated that the disclosures herein are not limited to high-degree flow turning in ducted wings. The disclosures herein may be similarly applied to other components of an aircraft to facilitate high-degree flow turning including, for example ducted tails. Examples of ducted tails and aircraft with ducted tails re described in commonly ownedU.S. Patent Application No. 19 / 224,369 titled “Aircraft with Ducted Wing and / or Ducted Tail,” which is incorporated by reference herein in its entirety.

[0047] Figure 1 illustrates an example of an aircraft wing 100 with an array of embedded propulsors 102. The array of propulsors define an inlet area 104 at a leading edge 106 of the aircraft wing 100 and define an exhaust area 108 at an aft end 110 of the aircraft wing forward of the trailing edge 112 of the aircraft wing. The aircraft wing 100, in this example, also includes a rotating flap assembly 114. As described herein, the flap assembly may be part of a flow turning control assembly positioned at the trailing edge 112 of the aircraft wing 100. In Figure 1, the flap assembly 114 is shown at a retracted position with a leading edge 116 of the flap assembly overlapping the trailing edge 112 of the aircraft wing 100. The flap assembly 114, in this example, includes two panels, a forward flap panel 118 and a rear flap 120 (which may also be referred to as a rear flap panel). The forward flap panel 118 thus defines the leading edge 116 of the flap assembly 114, and the rear flap 120 thus defines the trailing edge 122 of the flap assembly. In some examples, an aircraft wing may include a singular rotating flap rather than a flap assembly. In such examples, the singular rotating flap may include a single panel that defines both the leading edge and the trailing edge of the flap. It will be appreciated that the term, rotating flap, may be used to describe both a rotating flap having a singular panel or a rotating flap assembly having multiple panels.

[0048] The aircraft wing 100, in this example, also includes a pair of end walls 124a, 124b that facilitate the flow of thrusted air remaining attached to the upper surface of the flap assembly 114 during rotation. One end wall 124a may be attached to the aircraft wing 100 at the wing tip, and the other end wall 124b may be positioned on the opposite side of the wing at the wing root. In some examples, the fuselage or body of the aircraft may serve as the end wall at the wing root.

[0049] During operation, the array of embedded propulsors 102 propel a flow of air (e.g., a uniform sheet of thrusted air) across the upper surface 126 of the wing 100 aftward of the exhaust area 108 and across the upper surface 128 of the flap assembly 114. To turn the flow of thrusted air the flap assembly 114 rotates from the retracted position as shown in Figure 1 to a rotated position as shown in Figure 2. The aircraft wing 100, in this example, includes a flap assembly for each embedded propulsor 130 of the array of embedded propulsors 102. The array of embedded propulsors 102 in Figure 1 include five embedded propulsors 130. Not every embedded propulsor 130 is labeled in Figure 1. With five embedded propulsors 130, the aircraftwing 100, in this example, includes five flap assemblies. In other examples, an aircraft wing may have more or fewer embedded propulsors and more or fewer flap assemblies. In some examples, an aircraft wing may include a single flap assembly that extends across the entire span of the aircraft wing such that all embedded propulsors share the same flap assembly. In some examples, one set of adjacent embedded propulsors may share one flap assembly while another set of adjacent propulsors share another flap assembly. For example, in an aircraft wing having five embedded propulsors, two of the adjacent embedded propulsors may share one flap assembly and three of the embedded propulsors may share another flap assembly. As another example, one pair of adjacent embedded propulsors may share one flap assembly, another pair of adjacent embedded propulsors may share another flap assembly, and an individual embedded propulsor may have its own dedicated flap assembly. In some examples, the quantity and arrangement of flap assemblies may be the same for each wing of the aircraft while in other examples the quantity and / or arrangement of flap assemblies may be different for each wing of the aircraft.

[0050] Figure 2 A illustrates a top view of the aircraft wing 100 with the flap assembly 114 at a rotated position. In Figure 2A, the flap assembly 114 is rotated to its fully rotated position. The fully rotated position also may be referred to the maximally rotated position. A flap assembly thus may be described as being fully rotated or maximally rotated. A flap assembly rotated to a position between the retracted position and the fully rotated position may be referred to as partially rotated, and a rotated position between the retracted position and the fully rotated position may be referred to as a partially rotated position. As described herein, in some examples, a flap assembly may be rotated up to 90 degrees (90°). In such examples, therefore, the retracted position may be referred to the 0 degree (0°) position, and the fully rotated position may be a 90 degree rotated position. In some examples, the fully rotated position may be less than 90 degrees. In some examples, the fully rotated position may exceed 90 degrees. For example, a flap assembly may rotate up to a 180 degree (180°) rotated position (i.e., between a 0 degree position and a 180 degree position).

[0051] As seen in Figure 2A , a pivoting flap 132 has been deployed with the flap assembly 114 at its fully rotated position. At its deployed position, the pivoting flap 132 provides a surface 134 that extends from the trailing edge 112 of the aircraft wing 100 to the leading edge 116 of the flap assembly 114. By providing the surface 134 between the trailing edge 112 of the aircraft wing 100 and the leading edge 116 of the flap assembly, the thrustedairflow has a surface to adhere to and follow as the flap assembly 114 rotates to its rotated position. The thrusted airflow thus remains attached to the upper surface 128 of the flap assembly 114 and turns to follow the same rotation path as the flap assembly. Pivoting the pivoting 132 to the deployed position may occur within a relatively quick timeframe (e.g., less than a second).

[0052] Figure 2B illustrates a bottom view of the aircraft wing 100 with the flap assembly 114 at a rotated position and the pivoting flap 132 at a deployed position. Like Figure 2A, in Figure 2B, the flap assembly 114 is rotated to its fully rotated position. As noted above, a flap assembly 114 is provided for each embedded propulsor of the array of embedded propulsors of the aircraft wing 100 in this example. As also noted above, the flap assembly 114 may be part of a flow turning control assembly. The aircraft wing 100, in this example, thus includes a flow turning control assembly for each embedded propulsor of the array of embedded propulsors of the aircraft wing. Details regarding flow turning control assemblies are discussed below. As seen in Figure 2B, a flow turning control assembly includes an actuator 136 coupled to the pivoting flap 132. The actuator 136, in this example, is a pneumatic actuator having a piston 138 attached to the pivoting flap 132. As described herein, the actuator may be controlled to move the pivoting flap 132 between a stowed position and a deployed position. For example, a pneumatic actuator may be controlled to drive its piston toward the deployed position thus moving the pivoting flap toward the deployed position and to drive its piston away from the deployed position to move the piston toward the stowed position. In other examples, alternative types of actuators may be employed to drive the pivoting flap 132 between the stowed position and the deployed position including, for example, linear actuators, belt-drive actuators, and servos. As also seen in Figure 2B, a flow turning control assembly may include a retention cable attached to the pivoting flap to limit its movement in the direction of the deployed position. For example, the retention cable 140 may have a length that prevents the pivoting flap from pivoting past the deployed position.

[0053] Figure 3A illustrates an example of a flow turning control assembly 300 with a flap assembly 302 at a retracted position. Figure 3B illustrates the flow turning control assembly 300 with the flap assembly 302 at a deployed position. In Figure 3B, a pivoting flap has been omitted. The flap assembly 302, in this example, likewise includes a forward flap panel 304 and a rear flap 306. As described herein and as shown in Figure 3A, at the retracted position, the flap assembly 302 may be described as being at a 0 degree position indicated in Figure 3Aby dashed line 308. As also seen in Figure 3 A, at the retracted position, the forward flap panel 304 of the flap assembly 302 overlaps an upper surface 303 (Figure 3B) of an aircraft wing aftward of an exhaust area defined by an array of embedded propulsors. It will be appreciated that the upper surface of the aircraft wing aftward of the exhaust area is defined by the upper surface of the skin extending across the span of the aircraft wing. It will also be appreciated that the upper surface of the flap assembly 302 serves as the upper surface of the wing when the flap assembly is at the retracted position.

[0054] The flow turning control assembly 300, in this example, also includes a drive assembly 310 for driving the flap assembly 302 between the retracted and rotated positions and a mounting body 312 (mount) for mounting the flap assembly and the drive assembly. As discussed further herein, the mounting body 312 is configured to attach to the aft end of the aircraft wing. As also discussed further herein, a drive assembly such as the example drive assembly 310 may include a pair of left and right arcuate braces 314a, 314b that mount to respective sides of the rear flap 306 of the flap assembly. As seen in Figures 3A-B, the forward flap panel 304 of the flap assembly 302 mounts to respective sides of each brace 314a, 314b. The braces 314a, 314b, in this example, have an arcuate shape. The arcuate shape of the braces 314a, 314b may conform to an arc of a circle. The drive assembly 310, in this example, also includes a pair of toothed tracks 316a, 316b that mount to a respective one of the braces 314a, 314b. The toothed tracks 316a, 316b each engage a respective gear 318 of the drive assembly 310. Only one gear 318 is shown in Figures 3A-B, which engages the toothed track 316a. Like the braces 314a, 314b, the toothed tracks 316a, 316b, in this example, have an arcuate shape, which likewise may conform to an arc of a circle. The arc shape of the braces 314a, 314b and the toothed tracks 316a, 316b thus define the path of rotation for the flap assembly 302. The arcuate tracks described herein also may be referred to as racks. As such, a flap assembly that is rotated by driving an arcuate rack also may be referred to as a “rack flap” or a “rack flap assembly.”

[0055] The flow turning control assembly 300, in this example, also includes a lower skin panel 320 that moves with the flap assembly 302 during rotation. The lower skin panel 320 is shaped (e.g., curved) to provide a wing shape throughout the rotation of the flap assembly 302. For example, as shown in FIG. 3A, lower skin panel 320 may serve as a lower surface of the corresponding wing. As described further herein, a forward end 322 of the lower skin panel320 is configured to couple to the mounting body 312 and an aft end 324 of the lower skin panel is configured to couple to each of the braces 314a, 314b.

[0056] In Figure 3B, the example flap assembly 302 is shown in a fully rotated position, for example, a 90 degree rotated position indicated by dashed line 326. As noted above, a pivoting flap has been omitted from Figure 3B to illustrate the spatial separation between the trailing edge 328 of the wing 330 and the leading edge 332 of the flap assembly 302 when the flap assembly is at the rotated position. A pivoting flap as disclosed herein thus provides a surface for the flow of thrusted air to adhere to when the flap assembly 302 is at the rotated position. The pivoting flap may mount to the aft end 334 of mounting body 312. Figure 3B illustrates respective mounting points 336a, 336b at the aft end 334 of the mounting body 312 for mounting the pivoting flap.

[0057] Figure 4 illustrates a cross-sectional side view of an example of an aircraft wing 400 with an embedded propulsor 402 and a flow turning control assembly 404. The flow turning control assembly 404 may be the same as or similar to the flow turning control assemblies described herein. In Figure 4, the flap assembly 406 of the flow turning control assembly 404 is at its retracted position, and the pivoting flap 408 of the flow turning control assembly is shown at its stowed position. As noted above, the pivoting flap 408, in this example, is mounted to an aft body 412 at the aft end of the aircraft wing 400. As seen in Figure 4, at its stowed position, the trailing edge 414 of the pivoting flap 408 is positioned forward of the leading edge 416 of the pivoting flap. The pivoting flap 408 thus may be described as being stowed “upside down” at its stowed position. In Figure 4, a rotation path for the flap assembly 406 is indicated by dashed line 418, and a pivot path for the pivoting flap 408 is indicated by dashed line 420. As the flap assembly 406 rotates from the retracted position toward a rotated position, the pivoting flap 408 pivots aftward toward the deployed position such that, at its deployed position, the trailing edge 414 of the pivoting flap is positioned aftward of the leading edge 416 of the pivoting flap. As the flap assembly rotates from a rotated position toward the retracted position, the pivoting flap 408 pivots forward toward the stowed position.

[0058] As seen in Figure 4, the mounting body 422 of the flow turning control assembly 404 mounts to other structural members (e.g., spars, ribs) at the aft end 424 of the aircraft wing 400. As also seen in Figure 4, the geometry of the aircraft wing 400, the embedded propulsor 402, and the flow turning control assembly 404 constrains the length of the flap assembly 406. The flap assembly 406, in this example, likewise includes a forward flap panel 426 and a rearflap 428. When the flap assembly 406 is at its retracted position, the distance between the embedded propulsor 402 and the leading edge 430 of the forward flap panel 426 may be smaller than the distance between the trailing edge of the aircraft wing 400 and the leading edge of the flap assembly when the flap assembly is at its retracted position. Extending the length of the flap assembly may not be feasible due to the relatively short distance between the embedded propulsor 402 and the leading edge 430 of the flap assembly 404 as well as the relatively tight turning radius of the flap assembly. Deploying the pivot flap 420 as described herein advantageously accommodates these design constraints by providing a surface for the flow of thrusted air to adhere to between the trailing edge of the aircraft wing 400 and the leading edge of the flap assembly 406 when the flap assembly is positioned at a rotated position.

[0059] Figure 5A illustrates a cross-sectional side view of an example flap assembly 500 with a pivoting flap 502 at its stowed position. Figure 5B illustrates a cross-sectional side view of the example flap assembly 500 with the pivoting flap 502 actuated to its deployed position. The flap assembly 500 may be the same as flap assembly 114, flap assembly 302, or flap assembly 406 discussed above. In Figures 5A-B, the flap assembly 500 includes a pneumatic actuator 504 that drives the pivoting flap 502 between the stowed position and the deployed position. In Figure 5A, the piston 506 of the pneumatic actuator 504 has been retracted to position the pivoting flap 502 at the stowed position. In Figure 5B, the piston 506 of the pneumatic actuator 504 has been extended to position the pivoting flap 502 at the deployed position. As described herein, the pneumatic actuator 504 may be in signal communication with a controller (e.g., a computing device) that signals the pneumatic actuator 504 to retract or extend the piston 506. As also described herein, the controller may signal the pneumatic actuator based on a position of the flap assembly along the path of rotation. For example, the controller may signal (e.g., send a command) the pneumatic actuator 504 to extend the piston 506 to move the pivoting flap 502 to the deployed position before the flap assembly is maximally rotated (e.g., before a leading edge of the flap assembly no longer overlaps a trailing edge of the aircraft wing). As another example, the controller may signal (e.g., send a command) to the pneumatic actuator 504 to retract the piston 506 to move the pivoting flap 502 to the stowed position after the leading edge of the flap assembly overlaps the trailing edge of the aircraft wing as the flap assembly rotates toward the retracted position. In this way, the controller may ensure that no gaps are formed between the leading edge of the flap assembly and the trailing edge of the aircraft wing as the flap assembly rotates between a rotated positionand the retracted position. As also described herein, alternative types of actuators may be used to move the pivoting flap 502 between the stowed and deployed position.

[0060] Figure 6 illustrates an example of a pivoting flap 600. In Figure 6, a bottom surface 602 of the pivoting flap 600 is shown. Given the hinged attachment of the pivoting flap 600, its pivoting movement, and its position below an upper surface of the aircraft wing at its stowed position, the pivoting flap also may be referred to as a “lower door flap” or LDF. The pivoting flap 600 also includes an upper surface 604 opposite the bottom surface 602 that the flow of thrusted air adheres to when the pivoting flap is at the deployed position. As seen in Figure 6, the pivoting flap 600, in this example, has an arcuate shape. The curvature of the pivoting flap 600, in this example, thus provides a smooth transition from the curvature of the upper surface of the aft end of an aircraft wing to the curvature of the upper surface of the flap assembly. By providing a smooth transition across these upper surfaces, the pivoting flap 600 facilitates the flow of thrusted air remaining adhered to those surfaces when the flap assembly is at a rotated position.

[0061] The pivoting flap 600, in this example, also includes features that facilitate its deployment in a flow turning control system, the pivoting flap 600, in this example, includes an anchor point 606 for attaching an actuator (e.g., a piston of a pneumatic actuator) and an anchor point 608 for attaching a retention cable. The retention cable thus may act as a hard stop when attached to the pivoting flap 600. The pivoting flap 600, in this example, also includes respective mounting points 610 for attaching the pivoting flap to a mounting body of a flow turning control system (e.g., mounting body 312, 422).

[0062] Additional features of the pivoting flap 600 that facilitate its deployment in a flow turning control system include slots 612a, 612b that extend along the pivoting flap from its leading edge 614 to its trailing edge 616. The slots 612a, 612b, in this example, extend through the entire thickness of the pivoting flap 600 thus dividing it into a central panel 618 and two respective side panels 620a and 620b. The pivoting flap 600 also includes respective brackets 622a, 622b that respectively join the side panels 620a, 620b to the central panel 618. The brackets 622a, 622b, in this example a “U”-shaped with respective sides of the brackets being attached to the central panel and one of the side panels 620a, 620. For example, the bracket 622a joins the side panel 620a to the main panel 618, and the bracket 622b joins the side panel 620b to the main panel 618. The slots 612a, 612b and the brackets 622a, 622b are configured to permit passage of the braces and toothed tracks of the drive assembly (e.g., drive assembly310, 410) during rotation of the flap assembly from the retracted position to a rotated position. For example, the slots 612a, 612b have a width sufficient to receive and permit passage of a top edge of a brace of a drive assembly (e.g., brace 314a, 314b) during rotation of the flap assembly. At the rotated position, the top edge of the braces of the drive assembly may be received within the slots 612a, 612b. Given that the slots 612a, and 612b, in this example, extend through the entire thickness of the pivoting flap 600, the width of the slots also may be such that any gap between the slot walls and the top edge of the braces is minimized. In this way, the top edges of the braces of the drive assembly may act as a seal when received within the slots with the flap assembly at a rotated position. Similarly, the brackets 622a, 622b of the pivoting flap 600 are sized and shaped to permit passage of the braces (e.g., braces 314a, 314b) and toothed tracks (e.g., toothed tracks 316a, 316b) during rotation of the flap assembly. The brackets 622a, 622b thus each define a respective channel 624a, 624b for the braces and toothed tracks of the drive assembly to pass through during rotation. In some examples, a pivoting flap may include a groove that extends only partway through the thickness of the pivoting flap instead of slots that extend entirely through the thickness of the pivoting flap. In such examples, the upper surface of the pivoting flap may include no discontinuities (e.g., voids such as slots, holes, grooves, cavities, and the like).

[0063] Figures 7A-C illustrate respective views of an example flow turning control assembly 700 with the flap assembly 702 at respective retracted and rotated positions and with the pivoting flap 704 at respective stowed and deployed positions. The flow turning control assembly 700 may be the same as or similar to the flow turning control assemblies described herein. The flap assembly may be the same as or similar to the flap assemblies described herein. The pivoting flap 704 may be the same as or similar to the pivoting flaps described herein. In Figure 7A, the flap assembly 702 is at the retracted position with the pivoting flap 704 at the stowed position. In Figure 7B, the flap assembly 702 is maximally rotated (e.g., at or above a 90 degree rotated position) with the pivoting flap 704 at the deployed position. As seen in Figure 7B, at the deployed position, each brace 706 and track 708 is received within the bracket 710 of the pivoting flap 704. As also seen in Figure 7B, the top edge 712 of each brace 706 is received within a respective slot 714 (Figure 7C) extending along the pivoting flap. The top edge 712 of each brace thus fills the gap defined by the slots 714 of the pivoting flap 704, which facilitates a flow of thrusted air remaining adhered to the upper surface of the pivoting flap and flap assembly 702 during rotation. As seen in Figure 7C, with the pivoting flap 704 provides a surface 720 that extends from the trailing edge 722 of the aircraft wing 724 to the leading edge726 of the flap assembly 702. The surface 720 of the pivoting flap 704 thus likewise facilitates a flow of thrusted air remaining adhered to the upper surface of the pivoting flap and flap assembly 702 during rotation.

[0064] As also seen in Figures 7B-C and further described herein, a lower skin panel 728 is pivotably coupled to each brace 706 and a mounting body 730 to maintain a wing shape as the flap assembly 702 moves between the retracted position and a rotated position. The lower skin panel 728 may be the same as or similar to the lower skin panels described herein, and the mounting body 730 may be the same as or similar to the mounting bodies described herein.

[0065] Figure 8A and Figure 8B respectively illustrate a top perspective view and a bottom perspective view of an example rear flap 800 of a flap assembly. The rear flap may be the same as or similar to the rear flaps described herein. The rear flap 800, in this example, includes a mounting body 802 and a surface panel 804 above the mounting body. Braces of a drive assembly may mount to respective sides of the mounting body 802. The mounting body 802, in this example, also includes a forward flange for supporting a forward flap panel of a flap assembly. As described herein, a flap assembly may include a forward flap panel and a rear flap. The mounting body 802 of the rear flap 800, in this example, includes a flange 806 configure to support a forward flap panel of a flap assembly. In an assembled configuration, a forward flap panel may be supported on the flange 806 and mount to the mounting body 802.

[0066] Figure 9A and Figure 9B respectively illustrate a top perspective view and a bottom perspective view of an example forward flap panel 900 of a flap assembly. The forward flap panel 900 may be the same as or similar to the forward flap panels described herein. The forward flap panel 900, in this example, includes respective mounting flanges 902 for mounting the forward flap panel to a mounting body of a rear flap (e.g., mounting body 802 of the rear flap 800). As seen in Figures 9A-B, the thickness of the forward flap panel 900 changes from the leading edge 904 to the trailing edge of the forward flap panel. For example, forward flap panel 900 is relatively thinner at the leading edge 904 and relatively thicker at the trailing edge 906 with the thickness of the forward flap panel increasing in a direction from the leading edge to the trailing edge.

[0067] In Figure 10, a side view of an example side brace 1000 of a drive assembly is shown. The side brace 1000 may be the same as or similar to the braces described herein. The side brace 1000, in this example, includes a flap mounting section 1002 for mounting a rearflap of a flap assembly (e.g., rear flap 120, 306, 428, 800) and a track mounting section 1004 for mounting an arcuate track of a drive assembly (e.g., track 316a, 316b, 708). The brace 1000, in this example, also includes an arcuate slot 1006 for receiving an aft end of an aircraft wing (e.g., an upper skin panel) when the flap assembly is at the retracted position as shown, for example, in Figure 3 A. As described further herein, the brace 1000, in this example, further includes a linear slot 1008 for receiving on end of a translating bar that supports couplers that couple a lower skin panel (e.g., lower skin panel 320, 728), to the brace and translates during rotation of the flap assembly to pivot the lower skin panel.

[0068] Figure 11A shows portions of an example flap assembly 1100 and portions of an example drive assembly in an assembly configuration. In particular, the example flap assembly 1100 is shown in Figure 11A with a pair of side braces 1102a, 1102b mounted to respective sides of a rear flap 1104 in an assembled configuration. The side braces 1102a, 1102b may be the same as or similar to the side braces described herein. The rear flap 1104 may be the same as or similar to the rear flaps described herein.

[0069] In Figure 11B, a bottom rear perspective view of the example flap assembly 1100 is shown. As seen in Figure 11B, the flap assembly 1100, in this example includes a movable bar 1106 with respective ends of the bar being received and supported in one of the linear slots 1108a, 1108b of the side braces 1102a, 1102b. As also seen in Figure 1 IB, respective couplers 1110a, 1110b are mounted on the bar 1106 for supporting an aft end of lower skin panel (e.g., the lower skin panel 320, 728, 1200). As seen in Figure 11B, the couplers 1110a, 1110b each include a slot for receiving an aft end of the lower skin panel. The lower skin panel may be fastened to the couplers 1110a, 1110b via respective through holes in the lower skin panel and the couplers (e.g., using screws, bolts, and the like). With the lower skin panel coupled to the bar 1106 via the couplers 1110a, 1110b, the bar may translate along the slots 1108a, 1108b and rotate about its central axis during rotation of a flap assembly.

[0070] Figure 12A illustrates a top perspective view of an example of a lower skin panel 1200 for a flap assembly. The lower skin panel 1200 may be the same as or similar to the lower skin panels described herein. The lower skin panel 1200, in this example, has a curved shape to maintain a wing shape as the flap assembly rotates between the retracted position and a rotated position. The lower skin panel 1200, in this example, includes through holes 1202 at the leading edge 1204 and the trailing edge 1206 of the lower skin panel. The lower skin panel 1200, in this example, also includes respective slots 1208a, 1208b at the trailing edge 1206 ofthe lower skin panel for receiving the bottom edge of a respective brace (e.g., brace 314a, 314b, 706, 1102a, 1102b) of a drive assembly. The bottom edge of a brace being received in a slot of a lower skin panel is shown, for example, in Figures 3A-B, Figure 4, Figures 7B-C, Figures 12B-C, and Figure 13B. Figure 12B shows the example lower skin panel 1200, portions of a flap assembly 1208 and portions of a drive assembly 1210 in an assembled configuration. Figure 12C shows the example lower skin panel 1200, portions of the flap assembly 1208, and a mounting body 1212 in an assembled configuration. The mounting body 1212 may be the same as or similar to the mounting bodies described herein. As seen in Figure 12C, a bar 1214 is mounted on the mounting body 1212 with a pair of couplers 1216a, 1216b mounted on the bar. The bar 1214, in this example, is rotatable about its central axis. Similar to the couplers at the aft end of the lower skin panel (e.g., couplers 1110a, 1110b), each coupler 1216a, 1216b includes a slot for receiving the leading edge 1204 of the lower skin panel. The lower skin panel 1200 may be fastened to the couplers 1216a, 1616b via respective through holes in the lower skin panel and the couplers (e.g., using screws, bolts, and the like). With the lower skin panel 1200 coupled to the bar 1214 via the couplers 1216a, 1216b, the bar may rotate about its central axis during rotation of the flap assembly 1208.

[0071] Figure 13A illustrates a portion of an example drive assembly 1300. The drive assembly 1300 may be the same as or similar to the drive assemblies described herein. The drive assembly 1300, in this example, includes a motor 1302 (e.g., a servo motor), a pinion gear 1304 attached to the motor, a driven gear 1306 mounted on an axle 1308 and having teeth that engage the teeth of the pinon gear, and a pair of driving gears 1310a, 1310b mounted on the axle at respective ends of the axle, and a pair of arcuate tracks 1312a, 1312b having teeth that respectively engage the teeth of one of the driving gears. Figure 13A illustrates an alternative construction for arcuate tracks of a drive system. As seen in Figure 13 A, the arcuate tracks 1312a, 1312b, in this example, are not mounted to a brace and are relatively wider than other tracks disclosed and illustrated herein. The tracks 1312a, 1312b otherwise may be the same as or similar to the tracks described herein. The motor 1302 may be in signal communication with a controller. The controller may provide signaling (e.g., commands) indicating rotation of the flap assembly between the retracted position and a rotated position (e.g., a partially rotated position, a fully rotated position). The controller, for example, may provide signaling to the motor 1302 (e.g., a command) that causes the flap assembly to rotate the flap assembly toward a rotated position by driving the pinion gear 1304 in one direction, which causes the driven gear 1306 to rotate the axle 1308 thereby rotating the driving gears1310a, 1310b and causing the tracks 1312a, 1312b to drive the flap assembly toward the rotated position. At the rotated position, the control may provide additional signaling to the motor 1302 (e.g., another command) that causes the flap assembly to rotate toward the retracted position by driving the pinion gear 1304 in the opposite direction, which again causes the driven gear 1306 to rotate the axle 1308 thereby rotating the driving gears 1310a, 1310b and causing the tracks 1312a, 1312b to drive the flap assembly toward the retracted position. As seen in Figure 13, the motor 1302 and drive train (e.g., the pinion gear 1304, driven gear 1306, axle 1308, and driving gears 1310a, 1310b) may be housed within a mounting body 1314 of the flow turning control assembly. The mounting body 1314 may be the same as or similar to the mounting bodies described herein. The mounting body 1314, in this example, defines a central cavity 1316 and includes a bracket 1318 that mounts and supports the motor 1302 within the central cavity. In some examples, a mounting body may house respective bearings in surface contact with the tracks (e.g., tracks 1312a, 1312b) to facilitate rotation of the tracks when driving the flap assembly between the retracted and rotated positions.

[0072] Figure 13B illustrates the example drive assembly 1300 in an assembled configuration with portions of an example flap assembly 1320. The flap assembly 1320 may the same as or similar to the flap assemblies described herein. In Figure 13B, the mounting body 1314 has been omitted to illustrate the engagement of the drive train (e.g., the pinion gear 1304, driven gear 1306, axle 1308, and driving gears 1310a, 1310b) with the tracks 1312a, 1312b.

[0073] Figures 14A-B illustrate the turning radius of an example flap assembly 1400 of an example ducted wing 1402. The flap assembly 1400 may the same as or similar to the flap assemblies described herein. The ducted wing 1402 may be the same as or similar to the ducted wings described herein. The flap assembly 1400 is shown at the retracted position in Figure 14A and at a rotated position in Figure 14B. As described herein, the flap assembly 1400, in this example, is rotatable along a circular rotation path. The circular rotation path may be defined by a circle having an outer perimeter that aligns with the upper surface 1406 of the example flap assembly 1400 as shown in Figures 14A-B by dashed line 1404. As seen in Figures 14A-B, the circle defining the circular rotation path for the flap assembly 1400, in this example, has a center 1408 that is positioned below the ducted wing and forward of the flap assembly. In Figure 14A, the pivoting flap 1408 is shown in the deployed position with the flap assembly 1400 in the retracted position simply to illustrate that the pivoting flap follows thecircular rotation path of the flap assembly. It should be understood, however, that in operation the pivoting flap 1408 is deployed with the flap assembly 1400 at a rotated position.

[0074] The turning radius of a flap assembly (e.g., flap assembly 1400) may depend on the chord length (c) of the ducted wing (e.g., ducted wing 1402). The radius (r) of the circle that defines the circular rotation path for the flap assembly thus likewise may depend on the chord length of the ducted wing. The chord length 1410, in this example, may be measured from the leading edge 1412 of the ducted wing 1402 to the trailing edge 1414 of the flap assembly 1400 with the flap assembly at the retracted position as shown in Figure 14A. In some examples, the radius (r) of the circle that defines the circular rotation path of a flap assembly may be a percentage of the chord length (c). For example, the circle defining the circular rotation path for a flap assembly may have a radius that is between about 20% to about 35% of the chord length (c) (e.g., r / c = 20-35%). In some examples, the radius may be 25% or 30% of the chord length. In some examples, a ducted wing may have a chord length between about 1,000-1,100 millimeters (e.g., 1,050 mm) (1-1.1 meters, m), and the circle defining a circular rotation path for the flap assembly may have a radius between about 270-280 mm (e.g., about 275 mm). It will be appreciated that, depending on the design of the aircraft, in other examples, the chord length and corresponding radius of the circular rotation path may be different (e.g., larger) than the specific example values disclosed herein.

[0075] The flap assembly 1400, in this example, may have flap length ( / ) measured from (a) the position on the upper surface of the aircraft wing that the leading edge of the flap assembly touches with the flap assembly at the retracted position as shown in Figure 14A to (b) the trailing edge 1418 of the flap assembly with the flap assembly maximally rotated and the pivoting flap 1420 at the deployed position as shown in Figure 14B. In some examples, the ratio of flap length ( / ) to chord length (c) may be between about 0.4 and about 1.5 (e.g., I / c = 0.4-1.5). In some examples, the ratio of flap length to chord length may be between about 0.6 and about 0.7 (e.g., 0.63, 0.65, 0.67). In some examples, the flap length may be between about 750-760 mm (e.g., about 757 mm). It will again be appreciated that, depending on the design of the aircraft, in other examples, the flap length may be different (e.g., larger) than the specific example values disclosed herein.

[0076] Figures 15A-B illustrate an aircraft wing 1500 with an alternative type of flap assembly 1502 for flow turning control. Figure 15A illustrates a cross-sectional view of the aircraft wing 1500 and a portion of the flap assembly 1502. Figure 15B illustrates the aircraftwing 1500 with the flap assembly 1502 at a rotated position (e.g., a fully rotated position). As seen in Figures 15A-B, the aircraft wing 1500, includes slots 1504 formed in an upper surface 1506 across a span of an aircraft wing 1500. As described herein, a propelled flow airflow (e.g., a uniform sheet of thrusted air) adheres to the upper surface 1506 of the aircraft wing 1500 aftward of a propulsor array (e.g., an embedded propulsor array). The slots 1504, in this example, lead to channels formed through the body of the aircraft wing 1500. The channels 1508, in this example, each are sized and shaped to receive a respective rail of 1510 of the flap assembly 1502. The rails 1510 of the flap assembly 1502, in this example, are arcuate, “T”-shaped rails coupled to a bottom surface of the flap assembly. The channels 1508, in this example, have an arcuate contour that matches the arcuate shape of the rails 1510. A horizontal portion of each rail 1510 thus extends between respective lateral sides of a respective channel 1510, and a vertical portion of each rail extends into a respective slot 1504. The matching shape of the arcuate rails 1510 and the arcuate channels thus enable the flap assembly to move (e.g., slide) between a retracted position and a rotated position. The flap assembly 1502, in this example, similarly may include a forward flap panel and a rear flap as described herein. The flap assembly 1502 may be driven by a variety of actuators as described herein (e.g., pneumatic actuators, linear actuators, belt-drive actuators, and servos). The aircraft wing 1500, in this example, also may include one or more roller bearings respectively residing within each channel 1508 in surface contact with the rails 1510 to minimize friction and facilitate rotation of the flap assembly 1502 between the retracted position and a rotated position.

[0077] Figure 16 illustrates an example of an aerodynamic stator 1600 configured to reduce swirl in the airflow propelled by the propulsors of a ducted wing (e.g., the embedded propulsors 130, 402). An aerodynamic stator such as the aerodynamic stator 1600, in this example, may installed within a duct of a propulsor (e.g., an embedded propulsor) aftward of an aerodynamic rotor (e.g., a blade disk or “blisk”) and forward of a tail cone. In some examples, the aerodynamic stator may be configured to be mounted on or otherwise couple to a tail cone.

[0078] The aerodynamic stator 1600, in this example, includes an annular hub 1602 and multiple stator vane sectors 1604a-c radially extending from and circumferentially positioned around the hub 1602. The hub 1602, in this example, has a cylindrical shape whereby the radial thickness of the hub is less than an axial length of the hub.

[0079] Each stator vane sector 1604a, 1604b, 1604c, in this example, includes a respective axial wall 1606a, 1606b, 1606b extending forward from the hub 1602. The axial walls 1606a,1606b, 1606c, in this example, are spatially separated from each other around the circumference of the aerodynamic stator 1600. Each axial wall 1606a, 1606b, 1606c, in this example, includes respective radial stator vanes 1608a, 1608b, 1608c radially extending from one of the axial walls. The radial stator vanes 1608a-c, in this example, each have an airfoil shape. In some examples, radial stator vanes may have additional or alternative shapes. In some examples, stator vanes of an individual stator vane sector may have the same shape or may have different shapes. In some examples, stator vanes of one stator vane sector may have the same shape and stator vanes of another stator vane sector may have a different shape. In some examples, stator vane sectors may have stator vanes with the same combination of shapes. In some examples, stator vane sectors may have stator vanes with different combinations of shapes. The stator vane sectors 1604a-c, in this example, each include a pair of respective stator vanes 1608a, 1608b, 1608c. In some examples, a stator vane sector may have an alternative quantity of stator vanes (e.g., more or fewer stator vanes). In some examples, all stator vane sectors of an aerodynamic stator may have the same quantity of stator vanes. In some examples, stator vane sectors of an aerodynamic stator may have different quantities of stator vanes.

[0080] Each stator vane sector 1604a-c of the aerodynamic stator 1600, in this example, includes a respective shroud 1610a, 1610b, 1610c connected to and extending across the respective stator vanes 1608a-c of the stator vane sector. Similar to the axial walls 1606a-c, the shrouds 1610a-c, in this example, are spatially separated from each other around the circumference of the aerodynamic stator 1600. Each shroud 1610a-c, in this example, axially extends forward and aftward of the respective stator vanes 1608a-c of a stator vane sector 1604a-c. In other words, a leading edge of each shroud 1610a-c is positioned forward of a leading edge of each respective stator vane 1608a-c, and a trailing edge of each shroud is positioned aftward of a trailing edge of each respective stator vane. In addition, the circumferential edges of each shroud 1610a-c, in this example, are located at circumferential positions around the aerodynamic stator 1600 that are different from the circumferential positions of the tips of the stator vanes 1608a-c. As also seen in Figure 16, the circumferential width of the shrouds 1610a-c, in this example, is greater than the circumferential width of the axial walls 1606a-c. The collective shape of the axial walls 1606a-c may define a circle having a diameter that is sufficient to receive a tail cone of a propulsor; that is, the circle defined by the collective shape of the axial walls may, in some examples, be slightly bigger than the diameter of the tail cone such that the axial walls are in surface contact with an outer surfaceof the tail cone when the stator 1600 is installed in a propulsor. The collective shape of the shrouds 1610a-c likewise may define a circle having a diameter sufficient to be received in a duct of a propulsor; that is, the circle defined by the collective shape of the shrouds may, in some examples, be slightly smaller than the diameter of the propulsor duct such that the shrouds are in surface contact with an inner surface of the duct when the stator 1600 is installed in a propulsor.

[0081] An aerodynamic stator such as the aerodynamic stator 1600 may have a monolithic, contiguous construction. For example, an aerodynamic stator may be formed entirely of the same material (e.g., a plastic material such as acrylonitrile butadiene styrene (ABS) or nylon plastic, a metallic material such as aluminum, a composite material such as carbon fiber, and the like). In some examples, an aerodynamic stator may be constructed via milling, injection molding, material deposition, and the like.

[0082] Figure 17 illustrates a schematic view of an example flow turning control system 1700. As described herein, a flow turning control system such as the example flow turning control system 1700 includes one or more flap assemblies, for example, the flap assemblies 1702-1, 1702- / 7. As also described herein, a flap assembly such as flap assemblies 1702-1, 1702- / 7 each may include a respective rotating flap 1704-1, 1704- / 7 (rack flap). As further described herein, the flow turning control system 1700 includes respective pivoting flaps 1706-1, 1706- / 7 (smack flap), for each flap assembly 1702-1, 1702- / 7. The flap turning control system 1700, in this example, includes a controller 1708 (e.g., a microcontroller) configured to control operation of the flow turning control system. The controller 1708, in this example, includes memory 1710 storing executable control instructions 1712 and one or more processors 1714 that execute the control instructions to control operation of the flap assemblies 1702-1, 1702-n. The memory 1710 may include random access memory (RAM), read-only memory (ROM), or combinations of RAM and ROM. The controller 1708 thus may be implemented using software, firmware, or combinations of software and firmware. In some examples, the controller 1708 may receive updated control instructions that supplement and / or replace the control instructions 1712 stored in the memory 1710.

[0083] As described herein, one or more actuators such as actuators 1716-1, 1716- / 7 may be in mechanical communication with (e.g., mechanically coupled to) a respective pivoting flap 1706-1, 1706- / 7. The controller 1708 may be in signal communication with each actuator 1716-1, 1716- / 7 to control operation of the actuators 1716-1, 1716- / 7 based on the controlinstructions 1712, for example, to drive the pivoting flaps 1706-1, 1706- / 7 between the stowed and deployed positions.

[0084] As also described herein each flap assembly 1702-1, 1702- / 7 may be in mechanical communication with (e.g., mechanically coupled to) a drive train. The drive train may include a rack-and-pinion gear system to drive the rotating flap between the retracted position and a rotated position. A drive system may include a servo having a motor that drives rotation of the flap assembly. The flow turning control system 1700, in this example, thus includes a respective servo 1718-1, 1718- / 7 in mechanical communication with one of the flap assemblies 1702-1, 1702- / 7 and in signal communication with the controller 1708. The controller 1708 thus may control operation of the servos 1718-1, 1718- / 7 based on the control instructions 1712, for example, to drive the flap assemblies 1702-1, 1702- / 7 between the retracted positions and rotated positions.

[0085] As described herein, a flow turning control assembly such as the flow turning control system 1700 may include a respective limit switch 1720-1, 1720- / 7 for each flap assembly 1702-1, 1702- / 7 in order to detect when a flap assembly has reached the retracted position (e.g., the zero position). Each limit switch 1720-1, 1720- / 7, in this example, is in signal communication with the controller 1708. Each limit switch 1720-1, 1720- / 7 is positioned relative to a respective flap assembly 1702-1, 1702- / 7, such that the flap assembly comes into contact with the limit switch when the flap assembly reaches the retracted position. Upon contact with a flap assembly 1702-1, 1702- / 7, a limit switch 1720-1, 1720- / 7 may signal the controller 1708. In this way, the controller 1708 may monitor the position of each flap assembly 1702-1, 1702- / 7 during operation and determine (e.g., extrapolate) its current position during rotation based on the measured position of the corresponding servo 1718-1, 1718- / 7.

[0086] As also seen in Figure 17, the flow turning control system 1700, in this example, includes or otherwise is in signal communication with one or more input devices 1722-1, 1722-n. Input devices 1722-1, 1722- / 7 may include manual input devices (e.g., buttons, knobs, sliders, joysticks, touchscreens, and the like) and / or automated input devices (e.g., controllers, microcontrollers, avionics, sensors, and the like). In this way, rotation of one or more flap assemblies may be manually controlled or automatically controlled based, for example, on control instructions or feedback regarding the current condition or state of an aircraft, an aircraft wing, a propulsor (e.g., an embedded) propulsor, or other component of an aircraft.

[0087] Figure 18A illustrates a flowchart 1800a of example method steps for flow turning control. The steps shown in Figure 18A may be performed for flow turning control systems having one or multiple rotating flaps (e.g., multiple rotating flap assemblies). When a flow turning control system is powered on, the system may initialize (step 1802), for example, by performing an initialization procedure. In some examples, an initialization procedure may include moving each flap assembly toward the retracted position (step 1804) until the flap assembly contacts its respective limit switch (step 1806:Yes). If a flap assembly has not yet contacted its limit switch (step 1806:No), the flow turning control system may continue to drive the flap assembly toward the retracted position. When a flap assembly contacts a limit switch, the limit switch may signal the controller of the flow turning control system indicating that the flap assembly has reached its zero position (step 1808). With the flow turning control system powered up and initialized, the flow turning control system may monitor for an input signal indicating rotation of one or more flap assemblies to respective rotated positions (step 1810).

[0088] An input signal may indicate rotation of a single flap assembly or multiple flap assemblies. The input signal may indicate a rotated position of a flap assembly (e.g., a fully rotated position, a partially rotated position, a 90 degree rotated position, an x degree rotated position). The input signal may indicate a command position for a servo of a flap assembly. In some examples, a flow control system may receive an input signal indicating a rotated position of a flap assembly, and the controller of the flow control system may determine a command position for a servo used to drive rotation of the flap assembly (e.g., map, translate, convert, etc., the indication of the rotated position for the flap assembly to a command position for the servo). The flow control system may receive one input signal for all flap assemblies, an input signal for some but not all flap assemblies, and / or individual input signals for each respective flap assembly. One or more input signals may indicate rotation of multiple flap assemblies to the same rotated position and / or may indicate rotation of multiple flap assemblies to different respective rotated positions. For example, one or more input signals may indicate rotation of one or more flap assemblies to one rotated position (e.g., a fully rotated position, a 90 degree rotated position) and one or more other input signals may indicate rotation of one or more other flap assemblies to another, different rotated position (e.g., a partially rotated position, a 30 degree rotated position, a 45 degree rotated position). The controller of a flow turning control system may receive multiple input signals simultaneously (e.g., in parallel) and / or at different points in time (e.g., serially). In some examples, a flow turning control assembly may be configured to receive a discrete input signal via an input device (e.g., a button press-and-release, a switch activation, etc.) and control rotation of a flap assembly based on the discrete input signal. In some examples, a flow turning control assembly may be configured to receive a continuous input signal via an input device (e.g., a joystick displacement, a knob turning, a button press-and-hold, etc.) and control rotation of a flap assembly based on continued reception of the input signal whereby the flap assembly rotates while receiving the input signal and stops rotating based on no longer receiving the input signal.

[0089] Based on the input signal, the controller of a flow control system may signal one or more command positions to respective servos (step 1812) in order to drive respective flap assemblies to respective rotated positions. Operation of the servos may drive respective flap assemblies toward the rotated positions (step 1814) via respective drive assemblies. During rotation of the flap assemblies, the controller of the flow turning control system may receive feedback from each servo indicating the current measured position of the servo (step 1816). If the measured position of the servo does not match the signaled command position (step 1818:No), the drive assembly may continue to drive the flap assembly toward a rotated position (step 1814). If the measured position of the servo does match the signaled command position (step 1818:Yes), the drive assembly may cease driving rotation of the flap assembly, and the flow turning control system may wait to receive the next input signal (step 1820).

[0090] As each flap assembly rotates, the controller of the flow turning control system may monitor the measured position of each servo and compare it to a threshold position (step 1822). The threshold position may be the position at which the pivoting flap can deploy without a gap forming between a trailing edge of the aircraft wing and the leading edge of the flap assembly as the flap assembly rotates toward the rotated position. If the measured position of the servo does not match (e.g., does not equal, does not satisfy) the threshold position (step 1822:No), the drive assembly may continue to drive the flap assembly toward the rotated position (step 1814) with the flow turning control system continuing to receive feedback indicating the measured position of the servo (step 1816). If the measured position of the servo does match (e.g., equal, satisfy) the threshold position (step 1818:Yes), the flow turning control system may signal the actuator coupled to the pivoting flap of the flap assembly (step 1824) to drive the pivoting flap toward the deployed position (step 1826). With the pivoting flap pivoted to the deployed position, the controller of the flow turning control system again may wait to receive the next input signal (step 1820). The threshold position may be stored in memory at the controller of the flow control system. A threshold may be stored for all flap assemblies(e.g., a global threshold position) or for one or more flap assemblies (e.g., a group threshold position, an individual threshold position). The threshold position may be adjustable (e.g., to calibrate the rotated position at which a pivoting flap is deployed for one or more flap assemblies).

[0091] Figure 18B illustrates another flowchart 1800b of example method steps for flow turning control. The steps illustrated in Figure 18B may be performed with one or more flap assemblies rotated to a rotated position (e.g., a fully rotated position, a partially rotated position) and a corresponding pivoting flap pivoted to the deployed position. With the flap assembly rotated and the pivoting flap deployed, the controller of the flow turning control system may receive an input signal indicating rotation of one or more flap assemblies to the retracted position (step 1803). The received input signal may be the same as or similar to the input signals described herein. Based on the received input signal, the controller of the flow turning control system may signal one or more command positions to respective servos (step 1805). As described herein, a servo may drive a flap assembly toward the retracted position based on the signaled command position (step 1807). In some examples, the controller of the flow turning control system may be configured to signal the servo until a flap assembly contacts a respective limit switch. For example, as a flap assembly rotates toward the retracted position, the controller of the flow turning control system may monitor for contact with a limit control switch (step 1809). The limit switch may signal the controller indicating the flap assembly is at the zero position (step 1811) upon contact with the flap assembly. Based on receiving the signal from the limit switch, the controller may stop the corresponding servo (step 1813) and wait for the next input signal (step 1815), such as a signal indicating rotation of the flap assembly back to a rotated position.

[0092] As the flap assembly rotates back to the retracted position, the controller of the flow control system may monitor the measured position of the each servo in order to return a pivoting flap back to its stowed position. For example, the controller of a flow turning control system may receive a feedback signal indicating the respective measured position of each servo (step 1817). If the measured position of a servo does not match (e.g., does not equal, does not satisfy) the threshold position (step 1819:No), the controller may continue to monitor the measured position of the servo (step 1817). If the measured position of the servo does match (e.g., equal satisfy), the threshold position (step: 1819:Yes), the flow turning control system may signal the actuator coupled to the pivoting flap assembly (step 1821) to drive the pivotingflap toward the stowed position (step 1823). With the pivoting flap returned to the stowed position, the controller of the flow turning control system again may wait to receive the next input signal (step 1815).

[0093] Aspects of this disclosure further relate to one or more non-transitory computer-readable mediums that comprise computer-readable instructions that, when executed by a processor, cause the processor to perform at least one or more functions as disclosed herein, such as, but not limited to, controlling operation of flow turning control system such as driving a flap assembly between a retracted position and a rotated position, driving a pivoting flap between a stowed position and a deployed position, and / or other functions. Figure 19, for example, depicts a block diagram of example components of a controller (e.g., a microcontroller) or a computing device (e.g., a control unit) that may be part of or located remotely relative to an aircraft in accordance with aspects of the present disclosure. Figure 19 depicts one non-limiting example of a computer-readable medium according to some examples. Specifically, Figure 19 illustrates a block diagram of control computer 1950 for flow turning control (e.g., controlling a flap assembly, pivoting flap). Those skilled in the art will appreciate that the disclosures associated with Figure 19 may be applicable to any aircraft, aircraft wing, or propulsor described herein and / or combinations thereof. Control computer 1950 may include one or more processors, such as processor 1952-1 and 1952-2 (generally referred to herein as “processors 1952” or “processor 1952”). Processors 1952 may communicate with each other or other components via an interconnection network or bus 1954. Processor 1952 may include one or more processing cores, such as cores 1956-1 and 1956-2 (referred to herein as “cores 1956” or more generally as “core 1956”), which may be implemented on a single integrated circuit (IC) chip.

[0094] Cores 1956 may have a shared cache 1958 and / or a private cache (e.g., caches 1960-1 and 1960-2, respectively and referred to herein as “caches 1960”). One or more caches 1958 may locally cache data stored in a system memory, such as memory 1962, for faster access by components of the processor 1952. Memory 1962 may be in communication with the processors 1952 via a chipset 1966. Cache 1958 may be part of system memory 1962 in certain examples. Memory 1962 may include, but is not limited to, random access memory (RAM), read only memory (ROM), and include one or more of solid-state memory, optical or magnetic storage, and / or any other medium that can be used to store electronic information. Yet other examples may omit system memory 1962.

[0095] System 1950 may include one or more I / O devices (e.g., I / O devices 1964-1 through 1964-3, each generally referred to as I / O device 1964). I / O data from one or more I / O devices 1964 may be stored at one or more caches 1958, 1960 and / or system memory 1962. Each of VO devices 1964 may be permanently or temporarily configured to be in operative communication with a component of a flow turning control system, using any physical or wireless communication protocol.

[0096] Although the computer 1950 is shown on a single drawing, those of ordinary skill in the art with the benefit of this disclosure will appreciate that one or more components may be “remote” with respect to another component. For example, in one example, one or more components may be in a separate housing from one or more other components. In some examples, one or more components of the computer 1950 may only be in wireless communication with other components of the computer 1950. In some examples, one or more components of computer 1950 may be located on or within a portion of an aircraft, and yet other components may be located remote with respect to the aircraft.

[0097] Aircraft wings with embedded propulsors as described herein thus may enable various types of flight conditions, including hover, transition, and cruise conditions. For example, a flap assembly as described herein may be positioned at a fully rotated position (e.g., a 90 degree position) for a hover flight mode, at a retracted position for a cruise flight mode, and at a partially rotated position for a transition flight mode and for thrust vectoring. As described herein, multiple propulsors (e.g., an array of five propulsors, an array of six propulsors, an array of n propulsors) may be embedded respectively in each wing of an aircraft. In some examples, the propulsors may be capable of producing up to 1,780 Newtons (N) (400 Ibf, pound-force) of static thrust. The propulsors may be powered via an electric power source (e.g., one or more respective batteries). The disclosures provided herein thus may enable electric vertical take-off and landing (eVOTE) operations that avoids the flow of thrusted air separating from the surface of the wing in a variety of environmental conditions including in the presence of gusts and cross-winds and with the rotating flap in close proximity to a ground plane. Testing has demonstrated that flow separation can be avoided even in the presence of cross-winds up to 15 miles per hour (mph) with the rotating flap located only a few inches away from a ground plane.

[0098] Furthermore, modeling sound pressure levels (SPE) using Ffowcs Williams-Hawkings modeling has suggested that aircraft wings having features described herein (e.g.,embedded propulsors) reduce (or eliminate) spikes in noise output at audible frequencies around 4 kilohertz (kHz), 8 kHz, 12 kHz, and 16 kHz and at peaks within frequency ranges of 2.5-5 kHz, 3-5 kHz, 3.5-4.5 kHz. Such modeling also indicated that, even where relatively higher (noisier) SPLs were observed, such SPLs occurred at relatively lower frequencies (e.g., 0-500 Hz), which attenuate relatively quicker during propagation.

[0099] The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element. Furthermore, “about” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, and ±0.1% from the specified value, as such variations are appropriate according to the understanding of one of ordinary skill in the art. Throughout this disclosure, various aspects are presented in as numerical range. It should be understood that any description in describing a range is provided for convenience and brevity and should not be construed as an inflexible limitation. Where appropriate according to the understanding of one or ordinary skill in the art, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 5 (1-5) should be considered to have specifically disclosed subranges such as from 1 to 3 (1-3), from 1 to 4 (1-4), from 2 to 4 (2-4), from 2 to 5 (2-5), from 3 to 5 (3-5), etc., as well as individual numbers within that range, for example, 1, 2, 2.3, 3.03, 4.0, 4.75, 4.875, and 5.00 with an appropriate quantity of significant digits according to the understanding of one of ordinary skill in the art. This applies regardless of the breadth of the range.

[0100] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in any statement of examples is not necessarily limited to the specific features or acts described above. Furthermore, while aspects of the present disclosure have been described in terms of preferred examples, and it will be understood that the disclosure is not limited thereto since modifications may be made to those skilled in the art, particularly in light of the foregoing teachings. For example, although various examples are described herein, features and / or steps of those examples may be combined, divided, omitted, rearranged, revised, and / or augmented in any desired manner. Various alterations, modifications, and improvements will be appreciated bythose skilled in the art and are intended to be part of this description, even if not expressly stated herein, and are intended to be within the spirit and scope of the disclosures herein.

Claims

CLAIMSWhat is claimed is:

1. An aircraft wing comprising:an array of propulsors embedded in the aircraft wing, wherein the array of propulsors define an inlet area at a forward end of the aircraft wing and define an exhaust area at an aft end of the aircraft wing;one or more flow turning control assemblies, wherein each flow turning control assembly comprises:a first flap rotatable between a retracted position at a trailing edge of the aircraft wing and a rotated position away from the trailing edge of the aircraft wing; and a second flap pivotable during rotation of the first flap between a stowed position and a deployed position, wherein the second flap provides a surface that extends from the trailing edge of the aircraft wing to a leading edge of the first flap when pivoted to the deployed position; anda non-transitory computer-readable medium comprising executable instructions that, when executed by one or more processors, cause the one or more processors to:receive an input signal indicating rotation of the first flap toward the rotated position;initiate rotation of the first flap toward the rotated position based on the input signal; andcause the second flap to pivot to the deployed position before the first flap is maximally rotated.

2. The aircraft wing of claim 1 , wherein an upper surface of the second flap has a curvature that smoothly transitions from a curvature of an upper surface of the aft end of the aircraft wing to a curvature of an upper surface of the first flap.

3. The aircraft wing of claim 1, wherein the first flap is rotatable along a circular rotation path between the retracted position and the rotated position, wherein the circular rotation path is defined by a circle having a perimeter that aligns with an upper surface of the first flap.

4. The aircraft wing of claim 3, wherein the circle has a radius that is between about 20% to about 35% of a chord of the aircraft wing, the chord being measured from a leading edge of the aircraft wing to a trailing edge of the first flap with the first flap at the retracted position.

5. The aircraft wing of claim 4, wherein the radius is about 25% of the chord.

6. The aircraft wing of claim 3, wherein a ratio of a chord of the aircraft wing to a flap length is between about 0.4 and about 1.5, the chord being measured from a leading edge of the aircraft wing to a trailing edge of the first flap with the first flap at the retracted position, and the flap length being measured from the leading edge of the first flap with the first flap at the retracted position to a trailing edge of the first flap with the first flap at a maximally rotated position and with the second flap at the deployed position.

7. The aircraft wing of claim 6, wherein the ratio is about 67%.

8. The aircraft wing of claim 1, wherein the one or more flow turning control assemblies comprises a flow turning control assembly for each propulsor of the array of propulsors.

9. The aircraft wing of claim 1, wherein each flow turning control assembly further comprises a drive system coupled to the first flap, and wherein the instructions, when executed, cause the one or more processors to initiate rotation of the first flap by controlling operation of the drive system.

10. The aircraft wing of claim 9, wherein the drive system comprises:a motor;an axle coupled to the motor; anda pair of gears, wherein each gear is coupled to a respective end of the axle; and a pair of toothed arcuate tracks, wherein teeth of each track engage a respective one of the gears; anda pair of arcuate braces, wherein each brace is mounted to a respective one of the tracks and wherein each brace is mounted to a respective side of the first flap.

11. The aircraft wing of claim 10, wherein the second flap comprises:a pair of slots extending from a leading edge of the second flap to a trailing edge of the second flap, wherein the pair of slots divide the second flap into a central panel and a pair of side panels, and wherein each slot has a width sufficient to receive a top edge of a respective one of the braces; anda pair of brackets coupled to a bottom surface of the second flap, wherein each bracket couples the central panel to a respective one of the side panels, and wherein each bracket defines a channel having dimensions sufficient to receive a respective one of the tracks and a respective one of the braces during rotation of the first flap;wherein the top of each brace is received within a respective one of the slots when the second flap is pivoted to the deployed position and the first flap is rotated to the rotated position.

12. The aircraft wing of claim 1, wherein each flow turning control assembly further comprises an actuator coupled to the second flap, and wherein the instructions, when executed, cause the one or more processors to cause the second flap to pivot to the deployed position by controlling operation of the actuator.

13. The aircraft wing of claim 12, wherein the actuator is one of a pneumatic actuator, a linear actuator, a belt- drive actuator, or a servo.

14. The aircraft wing of claim 1, wherein the instructions, when executed, cause the one or more processors to cause the second flap to pivot to the deployed position before the first flap is maximally rotated based on the first flap being rotated to a threshold rotated position.

15. The aircraft wing of claim 1, wherein the instructions, when executed, cause the one or more processors to:receive an input signal indicating rotation of the first flap toward the retracted position; initiate rotation of the first flap toward the rotated position based on the input signal; andcause the second flap to pivot to the stowed position during rotation of the first flap toward the retracted position.

16. The aircraft wing of claim 1, wherein the first flap is a flap assembly comprising a forward flap panel defining the leading edge of the flap assembly and a rear flap aftward of the forward flap panel and defining a trailing edge of the flap assembly.

17. The aircraft wing of claim 1, wherein the first flap is rotatable up to 90° between the retracted position and the rotated position.

18. The aircraft wing of claim 1, wherein the first flap is rotatable at least 90° between the retracted position and the rotated position.

19. The aircraft wing of claim 18, wherein the first flap is rotatable up to 120° between the retracted position and the rotated position.

20. An aircraft comprising:a pair of wings, wherein each wing comprises an array of propulsors embedded at the aircraft wing, wherein the array of propulsors define an inlet area at a forward end of the aircraft wing and define an exhaust area at an aft end of the aircraft wing;at least one flow turning control assembly for each wing, wherein each flow tuning control assembly comprises:a first flap rotatable between a retracted position at a trailing edge of the aircraft wing and a rotated position away from the trailing edge of the aircraft wing; and a second flap pivotable during rotation of the first flap between a stowed position and a deployed position, wherein the second flap provides a surface that extends from the trailing edge of the aircraft wing to a leading edge of the first flap when pivoted to the deployed position; anda non-transitory computer-readable medium comprising executable instructions that, when executed by one or more processors, cause the one or more processors to:receive an input signal indicating rotation of the first flap toward the rotated position;initiate rotation of the first flap toward the rotated position based on the input signal; andcause the second flap to pivot to the deployed position before the first flap is maximally rotated.

21. The aircraft of claim 20, wherein:the leading edge of the first flap overlaps the trailing edge of the aircraft wing at the retracted position;an upper surface of the second flap has a curvature that smoothly transitions from a curvature of an upper surface of the aft end of the aircraft wing to a curvature of an upper surface of the first flap; andthe first flap is rotatable along a circular rotation path between the retracted position and the rotated position, wherein the circular rotation path is defined by a circle having a radius that is (a) between about 20% to about 35% of a chord of the aircraft wing, the chord being measured from the leading edge of the aircraft wing to a trailing edge of the first flap with the first flap at the retracted position and (b) between about 40% and about 150% of a flap length measured from a position of the leading edge of the first flap at the retracted position and a position of a trailing edge of the first flap at a maximally rotated position;wherein the instructions when executed, cause the one or more processors to cause the second flap to pivot to the deployed position during rotation of the first flap before the leading edge of the first flap does not overlap the trailing edge of the aircraft wing.

22. A method for facilitating turning a flow of propelled air, the method comprising: receiving an input signal indicating rotation of a first flap from a retracted position toward a rotated position, wherein the first flap is located at a trailing edge of a wing of an aircraft aftward of an exhaust area defined by an array of propulsors embedded at the aircraft wing, and wherein the first flap is rotatable between the retracted position and the rotated position;initiating rotation of the first flap toward the rotated position based on the input signal; andcausing a second flap to pivot from a stowed position to a deployed position during rotation of the first flap and before the first flap is maximally rotated, wherein the second flap provides a surface that extends from the trailing edge of the aircraft wing to a leading edge of the first flap when pivoted to the deployed position.

23. The method of claim 22, further comprising:receiving indicating rotation of the first flap toward the retracted position;initiate rotation of the first flap toward the rotated position based on the input signal; andcausing the second flap to pivot from the deployed position to the stowed position during rotation of the first flap toward the retracted position.

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