Compound Wing Vertical Takeoff and Landing Small Unmanned Aircraft System

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(12) United States Patent (io) Patent No.:

US 9,708,059 B2

Logan et al. (45) Date of Patent: Jul. 18,2017

(54) COMPOUND WING VERTICAL TAKEOFF (52) U.S. Cl.

AND LANDING SMALL UNMANNED CPC ............ B64C 39/005 (2013.01); B64C 15/00 AIRCRAFT SYSTEM (2013.01); B64C 39/024 (2013.01); (Continued) (71) Applicant: The United States of America as (58) Field of Classification Search represented by the Administrator of CPC ....... B64C 39/005; B64C 29/00; B64C 39/08; the National Aeronautics and Space B64C 39/024; B64C 2201/021; Administration, Washington, DC(US) (Continued) (72) Inventors: Michael J. Logan, Chesapeake, VA (56) References Cited (US); Mark A. Motter, Williamsburg, VA (US); Richard Deloach, Hampton, U.S. PATENT DOCUMENTS VA (US); Thomas L. Vranas, 2,082,674 A * 6/1937 Young ..................... B64C 27/16 Hampton, VA (US); Joseph M.

244/66 Prendergast, Boulder, CO (US); 2,347,230 A 4/1944 Zuck Brittney N. Lipp, Playa Del Rey, CA (Continued) (US) OTHER PUBLICATIONS (73) Assignee: THE UNITED STATES OF AMERICA AS REPRESENTED BY Michael J. Logan et al., "Experimental Optimization of a Free-to- THE ADMINSTRATOR OF THE Rotate Wing for Small UAS," AIAA Aviation, 32nd AIAA Applied NATIONAL AERONAUTICS AND Aerodynamics Conference, Jun. 16-20, 2014, pp. 1-6, Atlanta, GA.

SPACE ADMINISTRATION, Washington, DC (US) Primary Examiner Philip J Bonzell Assistant Examiner Steven Hawk (*) Notice: Subject to any disclaimer, the term ofthis (74) Attorney, Agent, or Firm Andrea Z. Warmbier patent is extended or adjusted under 35 (57) ABSTRACT U.S.C. 154(b) by 143 days.

Systems, methods, and devices are provided that enable (21) Appl. No.: 14/625,806 robust operations of a small unmanned aircraft system (sUAS) using a compound wing. The various embodiments (22) Filed: Feb. 19, 2015 may provide a sUAS with vertical takeoff and landing capability, long endurance, and the capability to operate in (65) Prior Publication Data adverse environmental conditions. In the various embodi- ments a sUAS may include a fuselage and a compound wing US 2016/0272315 Al Sep. 22, 2016 comprising a fixed portion coupled to the fuselage, a wing Related U.S. Application Data lifting portion outboard of the fixed portion comprising a rigid cross member and a controllable articulating portion (60) Provisional application No. 61/941,692, filed on Feb.

configured to rotate controllable through a range of motion 19, 2014.

from a horizontal position to a vertical position, and a freely rotating wing portion outboard of the wing lifting portion (51) Int. Cl.

and configured to rotate freely based on wind forces incident B64C 39/00 (2006.01) on the freely rotating wing portion.

B64C 39/02 (2006.01) B64C 15/00 (2006.01) 9 Claims, 8 Drawing Sheets loo-,

US 9,708,059 B2

Page 2 7,871,033 B2 * 1/2011 Karem .................... B64C 27/08 (52) U.S. Cl.

244/17.23 CPC .. B64C 2201/021 (2013.01); B64C 2201/088 7,922,115 B2 * 4/2011 Colgren .................... B64C 9/02 (2013.01); B64C 2201/165 (2013.01) 244/120 (58) Field of Classification Search 7,997,526 B2 * 8/2011 Greenley ............... A63H 27/02 CPC .......... B64C 2201/108; B64C 29/0083; B64C 244/12.4 8,083,172 B2 * 12/2011 Karem .................... B64C 3/185 29/0075; B64C 2201/088 244/7 C USPC .............................. 244/7 R, 7 C, 8, 12.4, 39 8,505,846 B1 * 8/2013 Sanders, II ........... B64C 11/003 See application file for complete search history.

244/7 A 8,646,720 B2 * 2/2014 Shaw ...................... B64C 27/20 (56) References Cited 244/17.23 8,991,751 B2 * 3/2015 Page ....................... B64C 29/02 1~~.`!!~~~ ~1►~ r ~Z~ZQ~1►d~1►~ C 244/39 9,102,401 B2 * 8/2015 Collins ............... B64C 29/0033 3,035,789 A * 5/1962 Young ................. B64C 29/0033 9,120,560 B1 * 9/2015 Armer ................. B64C 29/0008 244/48 2002/0003189 Al* 1/2002 Kuenkler ............... B63H 5/125 3,107,882 A * 10/1963 Matteson ............ B64C 29/0033 244/26 244/48 2002/0100834 Al 8/2002 Baldwin 3,139,248 A * 6/1964 Alvarez-Calderon .... B64C 3A2 2004/0245374 Al* 12/2004 Morgan .............. B64C 29/0025 244/207 244/12.3 3,181,810 A * 5/1965 Olson ................. B64C 29/0033 2005/0109874 Al 5/2005 Baldwin 244/66 2005/0151001 Al 7/2005 Loper 3,291,242 A * 12/1966 Tinajero ................... B60V 1/04 2005/0230520 Al* 10/2005 Kusic ...................... B64C 27/08 180/116 244/12.4 3,335,977 A * 8/1967 Meditz ...................... B64C 3/42 2006/0157616 Al* 7/2006 Kusic ...................... B64C 27/08 244/12.4 244/17.23 3,430,894 A * 3/1969 Levinsky ................ B64C 3/385 2006/0214052 Al 9/2006 Schlunke 244/211 2007/0215748 Al 9/2007 Robbins et al.

3,666,209 A * 5/1972 Taylor ................. B64C 29/0033 2008/0223979 Al 9/2008 Schlunke 244/12.4 2009/0008499 Al* 1/2009 Shaw ...................... B64C 27/20 3,730,459 A * 5/1973 Zuck ......................... B64C 3/38 244/17.23 244/48 2009/0140095 Al 6/2009 Sirohi et al.

5,096,140 A * 3/1992 Dormer, Jr.......... B64C 29/0033 2009/0266942 Al* 10/2009 Karem ................ B64C 29/0033 244/12.4 244/7 C 5,098,034 A * 3/1992 Lendriet ................. B64C 3/385 2010/0140415 Al 6/2010 Goossen 244/12.5 2010/0193625 Al 8/2010 Sommer 5,115,996 A * 5/1992 Moller ................ B64C 29/0025 2010/0230547 Al 9/2010 Tayman 239/265.19 2011/0036955 Al* 2/2011 Karem ...................... B64C 3/10 5,340,057 A * 8/1994 Schmittle ................ B64C 3/385 244/7 C 244/39 2011/0144834 Al 6/2011 Sommer 5,395,073 A * 3/1995 Rutan ..................... B64C 3/385 2011/0168851 Al 7/2011 Cherepinsky 244/38 2011/0315809 Al* 12/2011 Oliver ................. B64C 29/0033 5,509,623 A * 4/1996 Schmittle ................ B64C 3/385 244/12.4 244/113 2012/0048990 Al 3/2012 Sommer 5,758,844 A * 6/1998 Cummings ......... B64C 29/0033 2012/0097801 Al 4/2012 Barrett 244/12.4 2012/0119016 Al* 5/2012 Shaw .................. B64C 29/0025 5,765,777 A * 6/1998 Schmittle ................ B64C 3/385 244/12.3 244/17.25 2012/0234968 Al* 9/2012 Smith ................. B64C 29/0033 5,769,359 A * 6/1998 Rutan ..................... B64C 3/385 244/120 244/12.3 5,823,468 A * 10/1998 Bothe ....................... B64B 1/08 2013/0062455 Al* 3/2013 Lugg ................... B64C 29/0025 244/12.3 244/12.3 5,863,013 A * 1/1999 Schmittle ................ B64C 3/385 2014/0316608 Al 10/2014 Alber et al.

244/104 LS 2014/0339372 Al* 11/2014 Dekel ................. B64C 29/0033 5,941,478 A * 8/1999 Schmittle .................. B64C 1/00 244/7 R 244/120 2014/0352462 Al 12/2014 Wood 6,367,736 B1 * 4/2002 Pancotti ................. B64D 35/08 2015/0028151 Al* 1/2015 Bevirt ................. B64C 29/0025 244/48 244/6 6,607,161 B1* 8/2003 Krysinski ................. B64C 9/00 2015/0136897 Al* 5/2015 Seibel ................. B64C 29/0033 244/56 244/6 7,802,754 B2 * 9/2010 Karem ................ B64C 29/0033 244/12.4 * cited by examiner

Jul. 18,2017 Sheet 1 of 8

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Jul. 18,2017 Sheet 2 of 8

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Jul. 18,2017 Sheet 3 of 8

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Jul. 18,2017 Sheet 4 of 8

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Jul. 18,2017 Sheet 5 of 8

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Hybrid Mission VITOL Launch & Recovery 0.

Transit Distance(2km)

FIG. 9

Jul. 18,2017 Sheet 6 of 8

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DESIGN-EXPERT@ SOFTWARE PARETO CHART(RECOVERY) RECOVERY A:CAMBER 4.78- PIVOT LOCATION B: PIVOT C: CG m POSITIVE EFFECTS ID NEGATIVE EFFECTS 3.59- BONFERRONI LIMIT 3.01362 W W U_ W EFFECTIVENESS c, 2.39- LU t-VALUE LIMIT 2.09302' CAMBER C.G.

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Jul. 18,2017 Sheet 8 of 8

U.S. Patent US 9,708,059 B2

Lift

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FIG. 12

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COMPOUND WING VERTICAL TAKEOFF lating portion configured to rotate controllable through a range of motion from a horizontal position to a vertical AND LANDING SMALL UNMANNED position, and a freely rotating wing portion outboard of the AIRCRAFT SYSTEM wing lifting portion and configured to rotate freely based on 5 wind forces incident on the freely rotating wing portion.

CROSS-REFERENCE TO RELATED PATENT These and other features, advantages, and objects of the APPLICATIONS present invention will be further understood and appreciated by those skilled in the art by reference to the following This patent application claims the benefit of and priority specification, claims, and appended drawings.

to U.S. Provisional Patent Application No. 61/941,692, filed on Feb. 19, 2014, the entire contents of which are hereby BRIEF DESCRIPTION OF THE SEVERAL incorporated by reference in their entirety.

VIEWS OF THE DRAWINGS STATEMENT REGARDING FEDERALLY The accompanying drawings, which are incorporated SPONSORED RESEARCH OR DEVELOPMENT herein and constitute part of this specification, illustrate 15 exemplary embodiments of the invention, and together with The invention described herein was made in part by the general description given above and the detailed descrip- tion given below, serve to explain the features of the employees of the United States Government and may be invention.

manufactured and used by and for the Government of the FIG. 1 is a component block diagram illustrating a top United States for governmental purposes without the pay- 20 view of an embodiment compound wing in a forward flight ment of any royalties thereon or therefore.

configuration.

FIG. 2 is a component block diagram illustrating a top BACKGROUND OF THE INVENTION view of the embodiment compound wing in a vertical flight configuration.

Small unmanned aircraft systems (sUASs), such as 25 FIG. 3 is a component block diagram illustrating a right unmanned aircraft systems weighing a few pounds, are side view ofthe embodiment compound wing in the forward growing in popularity and the sUAS industry is estimated to flight configuration with the freely rotating outboard wing become an eight billion dollar a year industry. One of the portion aligned with the wing lifting portion and fixed wing main challenges faced in the operation of current sUASs is portion.

that current sUASs tend to have great difficulty operating in FIG. 4 is a component block diagram illustrating a right so gusty or adverse wind conditions. Because of the current side view ofthe embodiment compound wing in the forward sUAS's light weight and relatively small size, environmen- flight configuration with the freely rotating outboard wing tal factors can have a tremendous impact on the current portion rotated down with respect to the wing lifting portion sUAS's ability to operate, navigate, and conduct a mission.

and fixed wing portion.

Currently, in many areas of the United States, even if the FIG. 5 is a component block diagram illustrating a right Federal Aviation Administration (FAA) allowed the use of 35 side view ofthe embodiment compound wing in the forward current sUASs for commercial flights, the environmental flight configuration with the freely rotating outboard wing conditions (e.g., wind) limit operations, in some cases, to portion rotated up with respect to the wing lifting portion only about twenty five percent of the available flight hours. and fixed wing portion.

The environmental restrictions imposed on current sUASs FIG. 6 is a component block diagram illustrating a right limit the use of current sUASs by the United States' 19,000 40 side view of an embodiment small unmanned aircraft system first responder agencies and present a heavy penalty on the (sUAS) in a vertical flight configuration with the freely life saving uses of sUASs. rotating outboard wing portion rotated up with respect to the In addition to robust performance in varying environmen- fixed wing portion and the wing lifting portion rotated tal conditions, a need exists for sUASs having a combination vertically.

ofextended endurance, vertical takeoff and landing(V/TOL) FIG. 7 is a component block diagram illustrating a right capability, and low cost. Past attempts at multi-rotor and side view of the embodiment sUAS in a forward flight helicopter sUASs have had too short endurance times to configuration.

meet the need. Past attempts at fixed wing sUASs have FIG. 8 is a component block diagram illustrating a right required significant takeoff and landing areas that are not side view of the embodiment sUAS in a forward flight suitable for all applications. Additionally, past attempts at configuration with the freely rotating outboard wing portion gust resistant wing structures for multi-rotor and helicopter rotated down with respect to the wing lifting portion and sUASs have encountered large penalties associated with fixed wing portion.

their configurations, e.g., loss of lift, inefficient structure, FIG. 9 is a hybrid mission profile enabled by the various etc. embodiments.

55 FIGS. 10 and 11 are graphs of results of experiments of BRIEF SUMMARY OF THE INVENTION the effect of wing camber on gust damping or lift at the neutral angle of attack.

The systems, methods, and devices of the present inven- FIG. 12 is a graph illustrating results of experiments tion enable robust operations of a small unmanned aircraft conducted to determine a range of optimality for the pivot system (sUAS) using a compound wing. The various 60 location and center of gravity location of the embodiment embodiments may provide a sUAS with vertical takeoff and freely rotating outboard wing portion.

landing capability, long endurance, and the capability to operate in adverse environmental conditions. In the various DETAILED DESCRIPTION OF THE embodiments a sUAS may include a fuselage and a com- INVENTION pound wing comprising a fixed portion coupled to the 65 fuselage, a wing lifting portion outboard of the fixed portion For purposes of description herein, it is to be understood comprising a rigid cross member and a controllable articu- that the specific devices and processes illustrated in the

US 9,708,059 B2

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attached drawings, and described in the following specifi- FIG. 1 is a component block diagram illustrating a top cation, are simply exemplary embodiments of the inventive view of an embodiment of a compound wing 100 in a concepts defined in the appended claims. Hence, specific forward flight configuration. While FIG. 1 only illustrates a dimensions and other physical characteristics relating to the right side portion of an overall compound wing, one of embodiments disclosed herein are not to be considered as 5 ordinary skill in the art will understand that a left side limiting, unless the claims expressly state otherwise. portion of the overall compound wing would be the mirror The word "exemplary"is used herein to mean "serving as image of that illustrated in FIG. 1. The compound wing 100 an example, instance, or illustration." Any implementation may include a fixed wing portion 102 that may be coupled described herein as "exemplary" is not necessarily to be to the fuselage of the sUAS. Outboard of the fixed wing to construed as preferred or advantageous over other imple- portion 102 may be a wing lifting portion 104. The wing mentations. lifting portion 104 may include two portions: a rigid cross The various embodiments will be described in detail with member 104a that is configured not to articulate and a single reference to the accompanying drawings. Wherever pos- controllably articulating portion 104b that is configured to sible, the same reference numbers will be used throughout 15 move from a horizontal position in line with the fixed wing the drawings to refer to the same or like parts. References portion 102 to a vertical position perpendicular to the fixed made to particular examples and implementations are for wing portion 102. The controllably articulating portion 104b illustrative purposes, and are not intended to limit the scope may include a lifting motor 105 and propeller 107 that may of the invention or the claims. be controlled to provide lifting force in the V/TOL mode The various embodiments enable robust operations of a 20 when the controllably articulating portion 104b is rotated to small unmanned aircraft system (sUAS) using a compound the vertical position. In an embodiment,the lining motor 105 wing. The various embodiments may provide a sUAS with may be shut offin the forward flight mode and only operated vertical takeoff and landing capability, long endurance, and in the V/TOL mode. In another embodiment, the lifting the capability to operate in adverse environmental condi- motor 105 may continue to operate and provide forward tions. In an embodiment, each side of a compound wing of 25 thrust in the forward flight mode. While illustrated as having the sUAS (e.g., the left side wing and the right side wing of only one lifting motor 105 and propeller 107, additionally the sUAS) may include three portions: a first fixed inner lifting motors 105 and propellers 107 may be included in the portion located adjacent to the fuselage, controlled articu- controllably articulating portion 104b. Outboard ofthe wing lation intermediate portion outboard of the first fixed inner lifting portion 104 may be a freely rotating outboard wing portion, and a free-to-rotate outer portion outboard of the 30 portion 106. The freely rotating outboard wing portion 106 controlled articulation intermediate portion. The controlled may be coupled to the wing lifting portion 104 such that the articulation intermediate portion may include lift engines freely rotating outboard wing portion 106 is a tree-to-rotate mounted on a controllably articulating portion ofthe wing to portion of the wing 100 that freely rotates up or down based provide vertical lift in the vertical takeoff and landing on the forces, such as wind gusts, incident upon it in both the (V/TOL)mode.In an embodiment, the lift engines may shut 35 V/TOL flight mode and forward flight mode.

down during the forward flight mode when the controllable FIG. 2 is a component block diagram illustrating a top articulating portion is rotated to the horizontal position. In an view of the embodiment compound wing 100 in a vertical alternative embodiment, the lift engines may remain on and flight configuration (i.e., V/TOL mode). FIG. 2 illustrates be used during forward flight. In the various embodiments, that the controllably articulating portion 104b may be the lift engines on the various sides of the wings may be 4o rotated vertically such that the lifting motor 105 is perpen- independently controllable. dicular to the fixed wing portion 102.In the various embodi- In an embodiment,the sUAS may include an aft propulsor ments, control surfaces, such as ailerons, may be disposed that may be articulated and configured such that the thrust on the trailing edges of the wing portions 102, 104a, and/or being generated is always in the proverse (i.e., synergistic or 106.

favorable) direction. In an embodiment, the aft propulsor 45 FIG. 3 is a component block diagram illustrating a right may be rotated down during the V/TOL mode to provide side view of the embodiment compound wing 100 in the vertical balancing force and rotated up in the forward flight forward flight configuration with the freely rotating outboard mode to provide thrust with lift provided by the wing wing portion 106 aligned with the wing lifting portion 104 aerodynamics. In alternative embodiments, an aft pitch and the fixed wing portion 102. FIG. 3 illustrates the wing control motor and variable pitch propeller may be substi- 50 100 coupled to the fuselage 110 of a sUAS. FIG. 4 is a tuted for the aft propulsor. In other embodiments, a fixed component block diagram illustrating the right side view of pitch motor and propeller may be substituted for the aft the embodiment compound wing 100 in the forward flight propulsor. configuration with the freely rotating outboard wing portion In the various embodiments, the compound wing's free- 106 rotated down with respect to the wing lifting portion 104 to-rotate outer portions (i.e., the freely rotating outboard 55 and fixed wing portion 102. The freely rotating outboard wing portions) are allowed to freely rotate. The design ofthe wing portion 106 may rotate down a range of degrees "A" free-to-rotate outer portions may be such that the portions relative to the rest of the compound wing 100. FIG. 5 is a provide a balance between gust absorption and useful lift component block diagram illustrating the right side view of generation. the embodiment compound wing 100 in the forward flight In the various embodiments, a control system for the 60 configuration with the freely rotating outboard wing portion sUAS may be provided that provides both tandem and 106 rotated up with respect to the wing lifting portion 104 differential modes of control for the controllably articulating and fixed wing portion 102. The freely rotating outboard portion (i.e., a wing lifting portion) of the wing during wing portion 106 may rotate down a range of degrees "A"' forward flight and/or V/TOL flight. The control system may relative to the rest of the compound wing 100. Through the include a control architecture that encompasses both differ- 65 ability to freely rotate through the range of degrees A and A', ent operating modes and a considerable number of control the freely rotating outboard wing portion 106 may respond effectors. to gust of wind to stabilize the sUAS.

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FIG. 6 is a component block diagram illustrating a right impact on gust damping or lift at the neutral angle-of-attack.

side view ofan embodiment small unmanned aircraft system A second set of experiments was conducted to determine a (sUAS)600 in a vertical flight configuration with the freely range of optimality of the pivot location and e.g. location of rotating outboard wing portion 106 rotated up with respect the free-to-rotate portions. FIG. 12 is a graph illustrating to the fixed wing portion 102 and the controllably articu- 5 results of experiments conducted to determine a range of lating portion 104b rotated vertically. The sUAS 600 may optimality for the pivot location and center of gravity include a tail section 602 including one or more vertical location of the embodiment freely rotating outboard wing stabilizers 604. The sUAS 600 may also include aft propul- portion. The results illustrated in FIG. 12 indicate that lift sor 606 that may be articulated and configured such that the may be maximized by locating the pivot point as close to the thrust being generated is always in the proverse direction. io leading edge as possible while moving the e.g. as close to the The aft propulsor 606 is shown rotated down during the trailing edge as possible. Thus, the results indicate that lift V/TOL mode to provide vertical balancing force. In alter- may be increased when the pivot point is closer to the native embodiments, an aft pitch control motor and variable leading edge and the e.g. is farther from the leading edge.

pitch propeller may be substituted for the aft propulsor 606. The various embodiments may be used by first responders In other embodiments, a fixed pitch motor and propeller may 15 (e.g., police and fire) to provide search capabilities and fire be substituted for the aft propulsor 606. The sUAS 600 may monitoring capabilities, agriculture interests to provide crop also include a control system 607 connected to the aft monitoring, and utilities to provide pipeline monitoring, as propulsor 606, the lifting motor 105, the controllably articu- well as other capabilities applicable to the use of sUASs.

lating wing portions 104b, any other control surfaces, con- The preceding description of the disclosed embodiments trollable pitch propellers, and/or a payload 609, such as a 20 is provided to enable any person skilled in the art to make camera. The control system 607 may include one or more or use the present invention. Various modifications to these processor configured to control the operations of the aft embodiments will be readily apparent to those skilled in the propulsor 606 (e.g., speed, articulation, etc.), the lifting art, and the generic principles defined herein may be applied motors 105 (e.g., speed, etc.), the controllably articulating to other embodiments without departing from the spirit or wing portions 104b (e.g., tilt, etc.), any other control sur- 25 scope of the invention. Thus, the present invention is not faces (e.g., ailerons, rudder, etc.), controllable pitch propel- intended to be limited to the embodiments shown herein but lers (e.g., pitch, etc.), and/or a payload 609. The control is to be accorded the widest scope consistent with the system 607 may be connected to the various devices it following claims and the principles and novel features controls by one or more wire running throughout the sUAS disclosed herein.

600. The control system 607 may also include various 30 What is claimed is: sensors, such as airspeed sensors, altitude sensors, gyros, 1. A compound wing for a fuselage, comprising: GPS, etc., to enable control of the sUAS. For example, the a fixed wing portion couplable to the fuselage; control system 607 may include a MicropilotO MP2128 a wing lifting portion coupled to and disposed outboard of HELI2 autopilot control system including a 500 kph air- the fixed wing portion, comprising: speed sensor, 12 km altitude sensor, 3 axis acceleration and 35 a rigid cross member configured not to articulate; and rate gyroscopes, an ultrasonic altimeter and magnetometer, a single controllably articulating portion configured to integrated GPS receiver, and user definable error handling rotate controllably through a range of motion from a conditions, such as loss of RC command signal, loss of GPS, horizontal position in line with the fixed wing por- and UHF data/command link loss instructions. FIG. 7 is a tion to a vertical position perpendicular to the fixed component block diagram illustrating a right side view of 40 wing portion; and the embodiment sUAS 600 in a forward flight configuration. a freely rotating wing portion coupled to and disposed FIG. 7 illustrates that in forward flight mode the lifting outboard of the wing lifting portion and configured to motor 105 may be rotated down into the plane of the wing freely rotate based on wind forces incident on the freely and the aft propulsor 606 may be rotated up to the horizontal rotating wing portion.

position in line with the fuselage 110. FIG. 8 is a component 45 2. The compound wing of claim 1, wherein the control- block diagram illustrating a right side view of the embodi- lably articulating portion includes a lifting motor.

ment sUAS 600 in a forward flight configuration with the 3. The compound wing of claim 2, wherein the fixed wing freely rotating outboard wing portion 106 rotated down with portion is configured to be coupled to the fuselage of a small respect to the wing lifting portion 104 and fixed wing portion unmanned aircraft system (sUAS).

102. 50 4. A small unmanned aircraft system(sUAS),comprising: FIG. 9 is a hybrid mission profile enabled by the various a fuselage; and embodiments. The hybrid mission may provide a long transit a compound wing, comprising: distance capability, such as 2 km to/from station, and a long a fixed wing portion coupled to the fuselage; orbit time, such as 90 minutes on station. The hybrid mission a wing lifting portion coupled to and disposed outboard of may combine the attributes of a typical V/TOL mission and 55 the fixed wing portion, comprising: conventional takeoff and landing mission. a rigid cross member configured not to articulate; and Experiments were conducted to determine optimal basic a single controllably articulating portion configured to design parameters such as location of the pivot point of the rotate controllably through a range of motion from a free-to-rotate wing portions, location of the panel center-of- horizontal position in line with the fixed wing portion gravity (e.g.), and camber and/or airfoil to optimize lift to 60 to a vertical position perpendicular to the fixed wing drag in a rotating environment. Using a design-of-experi- portion; and ment analysis, a first set of tests were conducted to look at a freely rotating wing portion coupled to and disposed the impact of the camber, pivot, and e.g. in a simplified test outboard of the wing lifting portion and configured to apparatus. FIGS. 10 and 11 are graphs of results of experi- rotate freely based on wind forces incident on the freely ments of the effect of wing camber on gust damping or lift 65 rotating wing portion.

at the neutral angle of attack. Based on the results from the 5. The sUAS of claim 4, wherein the controllably articu- first set of tests, it appears as though wing camber has little lating portion includes a lifting motor.

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6. The sUAS of claim 5, further comprising: a fixed wing portion coupled to the fuselage; an aft propulsor configured to be articulated through a a wing lifting portion coupled to and disposed outboard range of motion from a second horizontal position to a of the fixed wing portion and having: downward position.

a rigid cross member configured not to articulate; 7. The sUAS of claim 6, wherein during a forward flight 5 and mode the controllably articulating portion is in the horizon- a single controllably articulating portion to which is tal position, the aft propulsor is in the second horizontal mounted a different one ofthe first and second lift position, and the freely rotating wing portion is free to rotate.

engines or motors, wherein the single controllably 8. The sUAS of claim 7, wherein during a vertical takeoff articulating portion is configured to rotate through and landing(V/TOL)flight mode the controllably articulat- to a range of motion from a horizontal position in ing portion is in the vertical position, the aft propulsor is in the downward position, and the freely rotating wing portion line with the fixed wing portion to a vertical is free to rotate.

position perpendicular to the fixed wing portion; 9. A small unmanned aircraft system (sUAS), comprising: and a fuselage; 15 a freely rotating wing portion coupled to and disposed independently controllable first and second lift engines or outboard of the wing lifting portion and configured motors configured to provide vertical lift in a vertical to rotate freely based on wind forces incident on the takeoff and landing mode and forward propulsion in a freely rotating wing portion; and forward flight mode; a control system configured to control operations of the an aft propulsor configured to be articulated through a aft propulsor, the first and second lifting engines or range of motion from a second horizontal position to a motors, and the controllably articulating wing portions, downward position; including independently controlling the first and sec- first and second compound wings positioned on opposite ond lifting engines or motors.

sides of the fuselage, each of the first and second compound wings including: