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INFLATABLE AND RIGIDIZABLE WINGS FORUNMANNED AERIAL VEHICLESDavid Cadogan *† , William Graham * ,Tim Smith *AbstractRecent shifts in tactical defense operations have led to aneed for improved capabilities in Unmanned AerialVehicles (UAVs). Several vehicle types such as thePredator are currently operational, and numeroussmaller specialized vehicles are under development.Many of the vehicles under development require theability to stow their wings and control surfaces intovery small volumes to permit gun launch or packaginginto aircraft mounted aerial drop assemblies. Onetechnology that has shown promise in achieving thisgoal is the inflatable wing.advanced this technology into a practical form for nearterm application (Figure 1). Maturation of the materialsused in inflatable structures such as space suits andMars landing craft impact attenuation airbags, has ledto an improved understanding of high strength fibersand laminates that are now used in high performanceinflatable wings [1]. Fabrics with high strength toweight ratios such as Kevlar, Vectran, and PBO, haveenabled inflatable wing designs that possess a highpacking efficiency.Inflatable wings have been demonstrated in manyapplications over the past five decades, includingaircraft, UAVs, airships, and missile stabilizationsurfaces. Recent advancements in high strength fibersand rigidizable materials have enabled higherperformance designs for modern application. Theinclusion of “smart materials” has provided theopportunity to impart a multi-functional capability toinflatable wings. Such materials include electronictextiles,which provide the potential for the integrationof numerous functions directly into the structure of thewing such as shape modification for control andmorphing, power generation and storage, antennas, andsensing.Past, present, and future developments of inflatable andrigidizable wing structures for use on UAVs, airships,and other applications are presented. Patents exist andare pending for information discussed in this paper.IntroductionInflatable wings have been in existence for decades andhave found application in manned aircraft, UAVs,munitions control surfaces, and Lighter Than Air (LTA)vehicles such as aerostats. Recent system designchallenges have ushered advances in the areas ofmaterials, manufacturing, and configuration that have* ILC Dover, Inc., Frederica, DE† Associate Fellow AIAA Member AIAA2 nd AIAA “Unmanned Unlimited” Systems, San Diego,CA, Sept. 2003 AIAA 2003-6630Copyright © 2003 by ILC Dover Inc.Published by the American Institute of Aeronautics andAstronautics, Inc., with permissionFigure 1. Inflatable UAV Wing (ILC)Inflatable wings can be packed into volumes more thanten times smaller than their deployed volume withoutdamaging the structural integrity of the wing materials.Deployment can occur on the ground or in flight, in avery short duration on the order of fractions of a secondto a few seconds, depending on the size of the wing andthe type of inflation system used.The strength and stiffness of the inflatable wing aredictated by the type of material used, the cross-sectiondesign of the wing, and the internal pressure. It isdesirable to reduce the internal pressure to as low avalue as possible to reduce the mass of the inflationsystem and structure, and reduce leakage rates. Thepreferred approach uses a design that is comprised of aseries of fabric spars that run roughly perpendicular tothe aircraft body, and are attached to an upper andlower fabric restraining layer. This approach results ina cross sectional design that possesses a high moment1American Institute of Aeronautics and Astronautics

of inertia. The surface of the resultant inflated structurehas a “bumpy” appearance, as inflatable structuresapproximate the shape of a cylinder or sphere uponinflation. A skin can be added to the surface of thestructure to provide a smooth aerodynamic surface.Through appropriate design of the fabric patterns thatmake up the inflatable wing, a variety of wing shapescan be manufactured, including wings that possesscamber.One of the more notable features of an inflatable wingis its durability. The materials are robust and can bepacked and deployed numerous times in test or reusewith minimal degradation in performance. The use ofan inflatable reduces the likelihood of damage inshipping, handling, flight, and landing, through theimpact resiliency of the materials, and the naturalimpact absorption capabilities of an inflatable structure.As a result, there is less of a need for highly skilledsupport personnel in the field. A related property ofinflatable wing design is the ability of the wing torecover shape in flight if the load limit is exceeded andthe wing buckles.Another technology that can be used to create aninflatable wing with a high packing efficiency andimproved performance is rigidization. Rigidization isthe action by which a flexible inflatable structure isconverted into a rigid composite structure. Once a wingor other surface is “rigidized”, it no longer relies oninflation pressure to maintain its shape. Thistechnology has been most recently applied todeployable space structures such as antennas, solararrays, and solar sails [2]. Several mechanisms exist bywhich to rigidize a structure, including thermalchemicalreactions, UV-chemical reactions, andinflation gas-chemical reactions.The most notable advantage of a rigidizable structure, isthe increased stiffness that results compared to astructure supported by inflation pressure alone.Stiffness increases of an order of magnitude or morecan be achieved over comparable inflatable onlystructures. This will allow for the evolution of thinnerairfoils and improved aerodynamic performancecompared to a conventional inflatable wing. A furtheradvantage of a rigidizable wing is the elimination ofinflation gas dependence to maintain the shape of thestructure after deployment. Inflation gas is requiredonly to initially deploy the structure.Inflatable aerodynamic surfaces have been consideredfor use in several military UAVs [3,4,5]. These includethe Loitering Electronic Warfare Killer (LEWK)(Figure 2), the US Navy Forward Air Support Munition(FASM), the US Army Quicklook, and the SmallUnmanned Aerial Vehicle (SUAV).Figure 2. LEWK Prototype Vehicle (SAIC)BackgroundInflatable wing technology has been used in aircraftapplications since the 1950’s. Many concepts havebeen proposed since the 1930’s [6], and numerousincarnations are flying today, some are mentioned inthis paper. Goodyear Aerospace designed andmanufactured several prototype aircraft using inflatablecomponents during the 1950’s [7]. The GA-33Inflatoplane had capabilities comparable to a J3 Cub(Figure 3).Figure 3. The GA-33 Goodyear Inflatoplane (1956)The airplane was maneuvered into position like awheelbarrow on its own wheel and inflated within 5minutes to ~25 psi. It used a two-cycle 40 horsepowerNelson engine that was hand started. Its wing span was22 feet and had a length of 19 feet 7 inches. Theairplane held 20 gallons of fuel and carried a maximumweight of 240 lbs. Its range was 390 miles with anendurance of 6.5 hours. Its cruise speed was 60 mph.The inflatoplane could be dropped by container behindenemy lines as a means of rescuing downed pilots Itwas ideally suited for both land and water use. A totalof twelve Inflatoplanes were built. Development,testing, and evaluation of the inflatable airplanecontinued through 1972 and the project was finallyterminated in 1973.2American Institute of Aeronautics and Astronautics

The 2 place GA-466 Inflatoplane was also designed bythe Goodyear Company in the 1950s (Figure 4). Theairplane was inflated to ~25 psi in about 6 minutes.This aircraft used a 60 horsepower McCulloch 4318engine that was hand started. Its wing span was 28 feetand had a length of 19 feet 2 inches. The airplane held18 gallons of fuel and had a gross weight of 740pounds. The range of this airplane was 275 miles withan endurance of 5.4 hours. Its cruise speed was 55mph, stall speed was 43 mph, and had a maximumspeed of 70 mph.the NACA 0018 geometry. Aerostats are tethered to theground during operation and are used to carry anairborne radar platform for border surveillance. Theycan fly in winds of 60 kts, with gusts up to 90 kts. Thefins are constructed from a multi-ply fabric thatprovides gas retention and a structural layer to reactaerodynamic loading. The envelopes are constructedfrom a flexible composite material using thermal andradio frequency sealing techniques.Figure 6. 420,000ft 3 aerostatFigure 4. The GA-466 Goodyear InflatoplaneILC Dover employed inflatable wing technology in the1970s with the invention of the Apteron unmannedaerial vehicle (Figure 5). This small vehicle was able tobe stored in a small volume for ease in portability, andlaunched from any remote location. This aircraft had a5.1 ft wingspan, and a 0.5 hp engine. The entire craftweighed 7 lbs. Elevons were used for flight control.Inflatable fins of similar design have been tested indeployable munitions stabilization applications. Onesuch program was the Weapons Integration and DesignTechnology program (WIDT) for the Air ForceResearch Laboratory, Eglin AFB, Florida (Figure 7). Inthis program, various technologies including inflatablefins were developed for creating a compact vehiclepackage with a reduced radar signature for externalweapons carriage. The inflatable stabilization finprototypes were designed for use with 250 lb and 500 lbbombs, deployed at altitudes of 300 to 25,000 ft and atspeeds up to Mach 1.2. Inflation occurred in under 150milli-seconds using a CO 2 gas generator. The inflationpressure was 200 psi.Figure 5. The ILC Dover ApteronInflatable wing/fin technology has also beendemonstrated for several decades on lighter than air(LTA) vehicles that use tail-fin assemblies for stabilityand control (Figure 6). These vehicles range in sizefrom 15 ft long advertising vehicles to 595,000 ft 3aerostats [8]. The fins are symmetrical airfoils based onFigure 7. WIDT Munitions FinInflatable Wing DevelopmentInflatable wings constructed by ILC are typicallycomprised of a gas retaining bladder and a structuralrestraint that reacts inflation and aerodynamic loads3American Institute of Aeronautics and Astronautics

(Figure 8). Several methodologies have been used inthe past, including inflated tubes of various diameterscovered by a tensioned skin and sometimes supportedunderneath by a foam [9, 10, 11]. However, this paperfocuses on a highly efficient multi-spar approach,which provides several advantages over tubularapproaches.and if filled with a compressible spacer material, wouldhave little impact on the packing volume of the wing.Minimizing spacer material also limits the potential foradverse shape effects due to compression set of thismaterial during packing and storage.Figure 8. Inflatable Wing RestraintIn the multi-spar approach, wing stiffness is dictated byinternal pressure and the modulus of elasticity of therestraint material, and can be elevated through the useof higher strength and modulus materials that canwithstand higher internal pressures. The cross-sectionof this type of airfoil reveals that the geometry of thewing is defined by a series of intersecting cylinders(Figure 9).NACA 8318 with even spar distributionNACA 0018 Symmetrical with even spar distributionNACA 4318 with distributed spars & skinFigure 9. Inflatable Wing Cross-SectionsThe exterior of the wing has a “bumpy” appearance, butcan be covered with a skin to improve aerodynamics(Figure 10). The volume difference between theinflated shape and the ideal airfoil shape is minimal,Figure 10. Inflatable Wing with Skin in Wind TunnelInflatable wings can be made tapered, swept, or alteredin planform through appropriate patterning of therestraint. Similarly, with careful patterning, the airfoilcan be made to have camber. Fiber positioning is usedin the design of the external restraint and internal sparsto control elongation and therefore dimensionalaccuracy of the construction. The use of internal sparsto separate the upper and lower external restraintsyields a wing that optimizes the cross-sectional momentof inertia of the wing by maximizing internalpressurized area. This yields the lowest possibleinternal pressure required for the wing which in-turnyields lower potential for leakage, lower inflationsystem mass, and a lower packed volume.Inflatable Wing Materials - The restraints aremanufactured from high modulus fibers such as Kevlar,Vectran, or PBO. The fibers are selected based on thestorage and performance requirements of the vehicle(Tables 1 & 2). Packing characteristics also play alarge part in the selection of fibers. Some fibers, suchas PBO, are sensitive to compression failureexperienced in bending, which significantly degradesstrength and stiffness, and are less desirable. PBO alsodegrades when exposed to various wavelengths of light,reducing its tenacity. However, even with these factors,PBO still retains a large percentage of its strength andstiffness to make it competitive for various applications.Vectran has been used by ILC in numerous aerospaceapplications including the Mars Pathfinder and MERimpact attenuation airbags [1]. Notable properties ofthis fiber include excellent resistance to degradationfrom handling and packing, as well as an increase instrength in cold environments. Kevlar is another highstrength fiber that is slightly lower in cost and available4American Institute of Aeronautics and Astronautics

in a wide range of weaves. To date, inflatable wingshave been manufactured from Vectran and Kevlar.MaterialSPECTRA/DYNEEMASpecificGravityCostYarnTenacityTensileStrengthTensileModulusStraintoFailureg/cm^3 $/lb g/den x 10^3 psi x 10^6 psi %- Dyneema 0.97 23 40 507 16 3.5- 900 UHMW PE 0.97 23 375 17 3.5- 1000 UHMW PE 0.97 29 32 435 25 2.7VECTRANPBO- HS 1.41 22-90 23 412 9.4 3.3- M 1.4 15 9 161 7.6 2- AS 1.54 110 42 840 26 3.5- HM 1.56 110 42 840 39 2.5KEVLAR- 49 Aramid Fiber 1.46 25 23 420 9.8 2.5- 29 Aramid Fiber 1.46 15-40 23 420 12 3.6- 68 Aramid Fiber 1.46 15-40 420 25–26- 149 Aramid Fiber 1.55 25 18 340 21 1.45TECHNORA- T-240 1.45 15-30 28 414 15.8 4.4FIBERGLASS- S-Glass 2.49 5.5 21 665 13.5 5.7- E-Glass 2.6 0.85 15.1 500 12.4 4.8GRAPHITE/CARBON- H.S. Pan 1.7–1.8 20 21.3 410–580 33–36 2-2.5- UHS Pan 1.7–1.8 20 31.3 590–830 38-42 1.8- HM Pan/Pitch 1.8–2.0 20 14.2 250–500 50–80 0.4- UHM Pitch 2.0–2.2 20 11.9 300–360 90–130 0.3Packaging & Deployment - Several folding techniquescan be used to package the inflatable wings fordeployment. Random, z-folding, rolling, andcombinations are usually considered. Deployment rateand effects on flight dynamics are leading criteria in theselection of the method. Inflatable wings can pack intovolumes more than ten times smaller than theirdeployed volume. A well packed structure can exceedpacking efficiencies (package volume to materialvolume) of 60%.Deployment synchronicity is improved as the rates ofdeployment are increased. Some control can also beachieved through specific packing patterns and controlof the inflation path. This approach can also be used tobuild stiffness of the wing from the root duringdeployment, to eliminate the potential for wing foldback.Regardless of the path they take duringdeployment, inflatable wings always achieve their finalshape because of their robust nature. An example of awing with a 10:1 deployed to packed volume can beseen in Figure 11.Table 1. High Performance Fiber Physical PropertiesNumerous materials are available and suitable for thedesign and construction of the internal bladder.Material selection is typically driven by flex crackingand modulus at cold temperature, manufacturingprocess, resistance to gas permeation, and resistance todeveloping pinholes when folded or flexed.Polyurethane is often used, but specializedpolyurethane compounds and laminates, such asArmorflex, are also applicable. The materials used inthe construction of the inflatable wings have lowdielectric constant and are therefore low observablefrom a radar perspective.PROPERTYPOLYESTERTenacity (g/d) 8.3Modulus (g/d) 80Shrinkage @ 350°F, % 1.6Resistance to FlexCrackingUV DegradationHydrolytic StabilityOxidation ResistanceCoating AdhesionCreep Under LoadAbrasion ResistanceExcellentGoodGoodGoodExcellentGoodFairElongation @ Break 16.3Density 1.38KEVLAR SPECTRA VECTRAN22 30 23458 1400 525Minimal Decomposes @ 296°F MinimalPoor Excellent GoodPoor Good PoorExcellent Excellent ExcellentExcellent Excellent ExcellentGood Poor ExcellentExcellent Poor ExcellentPoor Excellent Good3.6 3.5 3.31.44 0.97 1.4Table 2. Fiber CharacteristicsFigure 11. Packed Inflatable WingSystem Analysis - There are several benefits anddrawbacks to the use of inflatable wings that must beconsidered by the user prior to selection of atechnology. The greatest advantage that inflatablesprovide over conventional structures is in packaging.This is usually at the core of a decision to considerinflatable structures for wings. Some higher orderbenefits and drawbacks of inflatable vs conventionallyconstructed (metal or composite) wings include thefollowing:Benefits:- High packing efficiency (low packed volume)- High G deployable- Robust / simple / reliable (no moving parts)5American Institute of Aeronautics and Astronautics

- Low cost- Long storage life- Recoverable / durable / reusable- Can be morphed or shape modified for control- Can recover shape if buckling occurs in flight (gustload)- Inflatable structures dampen vibrations wellDrawbacks:- Potential for leakage / ballistic penetration- Thicker airfoil required for high stiffness – lessefficient aerodynamically- Aspect ratio limited for high wing loading- Inflation system mass burden- Need for make-up gas (thermal/altitude excursions)This list is not inclusive but is representative of theaspects of the technology for consideration.Many of these drawbacks can be addressed by applyinga materials technology known as “rigidization”. In thisapproach, a flexible material is packed and deployed asin the case of the inflatable wing, but then undergoes achange in properties and becomes rigid, no longerrequiring the support of inflation gas to maintain itsgeometry. This approach will be discussed in the nextsection.Inflation Systems - Inflation systems can be configuredfrom several well understood technologies such asbottled compressed gas, chemical gas generators, feedlines from engine compressors, etc. DC electricblowers are used in aerostats and are very efficientsources of inflation gas in these low pressure systems.Inflation system selection will depend on severalcriteria focused on mission requirements such asdeployment time, thermal and altitude gradients afterdeployment, and the need for a pressurizationmaintenance source for long duration missions.Integrated Technologies – There are a number oftechnologies that are maturing rapidly that can expandthe inflatable wing’s performance, several of which arebeing studied for application. The collapsible anddeformable nature of a textile assembly makes aninflatable wing an attractive platform upon which toapply wing morphing techniques. Actuators can beapplied strategically to alter the shape, size and crosssection of the inflatable wing for various flight regimes.This approach has the potential to be extremely masseffective in comparison to mechanical technologies,especially if electronic textiles can be applied.Electronic textiles, or E-textiles, are an emerging classof materials that combine electrical components directlyinto textile materials, such as the restraint in this case[12]. These materials can be made to perform variousfunctions such as changing shape via constriction,producing power, acting as sensors or embeddedantennas, or as microcircuits.E-textiles are being developed for use in inflatable wingstructures as control mechanisms. Throughdeformation of the wing geometry, a simple method ofcontrol can be obtained that reduces part count andcomplexity of wing systems. Control of this nature alsoprovides a smooth transition at the trailing edge of thewing, thus reducing aerodynamic disturbances ofmechanical systems. This is accomplished throughconstriction or deformation of various componentswithin the inflatable wing structure, especially the aftthird of the airfoil, where loading and cross-sectionalstiffness are lower and can be more easily maneuvered.Examples of how Nastic cells, a biomemetic style ofactuation system noted in plants, are shown in Figure12. Through inflation of these small tubes,foreshortening the selected area can locally alter theshape of the wing. Deformation of this nature isdesirable for long duration camber change, but may betoo low in frequency response to be used as a controlmechanism.Inflated ActuatorsUn-Inflated ActuatorsFigure 12. Nastic Cells for Morphing Inflatable WingsThe most promising method of morphing wing shapesfor control purposes focuses on the use of piezoelectricmaterials. Several approaches of application of thesematerials to inflatable wings are currently underdevelopment. Two different types, Thunder andMacro-Fiber Composite (MFC) actuators produced byFACE International and Smart Material Inc.respectively, are being applied to the surface of wingsfor test. These can be applied in a localized or a globalformat. Figure 13 shows one method of altering theshape of the wing that is currently in test. Flattening ofthe bumps in the inflatable wing extends the surface runlength and thus deforms the shape of the wing.6American Institute of Aeronautics and Astronautics

Excitation can occur rapidly thus allowing thetechnique to be used for control applications via localmorphing.Un-deflected ActuatorsDeflected ActuatorsFigure 13. Piezoelectric Actuators for MorphingInflatable WingsRigidizable Wing DevelopmentA number of potential drawbacks have been identifiedand discussed with regard to inflatable wings. ILC hasdeveloped a technique for addressing these issues andcreating an inflatable wing that can be packaged into asmall volume, yet provide the same structural propertiesof a conventional composite or metal ring. This methodof transformation is known as “rigidization” and iscurrently being patented for this application.Rigidization is a process by which a flexible material isaltered physically by an external controlling influenceand becomes a solid composite structure [13, 14, 15,16]. Numerous mechanisms are available, but the mostpromising appear to be Ultra-Violet (UV), and InflationGas Reaction rigidization. UV Rigidization uses UVradiation to cause a chemical reaction (cure) in a matrixresin, and Inflation Gas Reaction resin uses an inflationgas that is loaded with a curative agent that reacts witha benign matrix resin in the structure. Once the wing ismade rigid, within seconds to minutes depending onresin chemistry, the wing no longer requires inflation toprovide structural stability.The most practical in the near term for wing structuresappears to be UV-chemical exposure. In this case, areinforcement fabric is coated with an uncured polymerthat chemically hardens when exposed to Ultra-Violetlight to form a composite structure. The UV source canbe the sun or from internal sources such as LEDs.Timing of the rigidization event is controlled by theresin chemistry, and can be on the order of tens ofseconds if required. The wavelength at which thematerial rigidizes can be shifted to accommodatemanufacturing and field use needs if required, or to cureat various rates under specified conditions. Resin cureis accelerated under elevated thermal conditions andmay require an integrated method of heating the wingsduring cure if very cold environments are encountered.The reinforcement fabric can be one of severalmaterials normally used in composite structures, butglass or quartz is normally preferred for ease of UVtransmission. Distributed reinforcements of higherperformance fibers such as carbon can be used ifrequired to further optimize structural efficiency. Forbrevity the UV system only will be discussed.The motivation for this work is to provide an inflatablewing with properties that approach that of a fixed rigidwing made from metal or composite materials. Amajority of the benefits of inflatable wings still exist,however, some of the drawbacks can now be addressed.This provides some advantages in several areasincluding the following:• Reduced puncture/leakage vulnerability• Stiffer than an inflatable wing (higher load factor)• Thinner, Higher Aspect Ratio Wing = Less Drag,improved aerodynamics• No gas leakage / make-up gas mass or complexity• Longer flight duration via efficient wing design• Smaller, Lighter Deployment System• Minimal inflation pressure required (3-5 psid)The are many benefits of this approach that lead to thepotential for some high performance UAV systems.However, there is still one limitation to this approach,which must be considered. The time duration of thecure of the composite and the design of the thin,potentially high aspect ratio inflatable wings, requirethat the wings not be “loaded” during rigidization. Inother words, the UAV will probably have to bedeployed and rigidized while suspended from aparachute. The parachute and possibly the inflationsystem can then be jettisoned prior to the flightcomponent of the mission. If the wings were to beaerodynamically loaded, they would have to rely on thedesign of the inflatable structure and thus have a thickercross-section and be inflated with a high-pressureinflation source.Inflatable rigidizable wing components are currentlybeing designed and fabricated in a university spacegrant consortium flight experiment program. In thiseffort the University of Kentucky is structuring a highaltitude balloon drop test for a UAV with inflatablerigidizable wings supplied by ILC. The wings will be7American Institute of Aeronautics and Astronautics

inflated and rigidized during ascent (from 60,000 to80,000 ft), and then the aircraft will be dropped from analtitude of approximately 80,000 ft. Photography andlocation transponders will be used to monitor thedeployment and flight characteristics of the wings. Inthis case the sun’s radiant energy will be used torigidize the wings.Several subsections of the wing were fabricated andtested to verify manufacturing techniques and structuralproperties of the rigidized component. The completedwing shown in Figure 14 is the test model of theinflatable rigidizable wing, manufactured from afiberglass/UV epoxy laminate.The technology is also scalable to accommodate theneeds of high altitude airships, munitions systems, andsimilar applications.AcknowledgmentThis work was possible through contributions byseveral people and organizations by way of fundingsupport, technology support, and materialsdevelopment. The authors wish to thank SAIC, TheUniversity of Kentucky Aerospace EngineeringDepartment, Mevicon, Adherent Technologies, NASALaRC Structures & Dynamics Branch, Office of NavalResearch and NASA DFRC for their support andinvolvement in this work.References[1] Cadogan D., Sandy C., Grahne M., Developmentand Evaluation of the Mars Pathfinder Inflatable AirbagLanding System, 49 th International AstronauticalCongress, 1998.[2] Cadogan D., Grahne M., Mikulas M., InflatableSpace Structures: A New Paradigm for Space StructureDesign, 49 th International Astronautical Congress,1998.[3] Palmer, M., LEWK Joins SAIC’s Growing Flock,SAIC Spectrum Newsletter, Fall 2001.Figure 14. UV Rigidized WingThe test unit was evaluated for structural stiffness andmanufacturing process accuracy. Information derivedfrom the sub-component tests was used in thedevelopment of the rigidizable wing section. This is aprototype of the wing that was successfully flown in theBIG BLUE balloon flight experiment in May of 2003[17]. The wing is a 16 spar symmetrical airfoil basedon a based on an E398 airfoil with a chord of 12 in, anda half span of 36 in. The airfoil is designed to support a10.4 lb vehicle with a 2G wing-loading, and has a factorof safety of > 2.0 over ultimate.Summary and ConclusionsSignificant advancements have been made withrespect to deployable inflatable wings over the past fewyears, which have made them both attractive and viablefor UAV application and design integration. Advancesin rigidization technologies that yield high stiffnessdeployable wings, multi-functional structures, andmorphing technologies, have expanded the utility of thetechnology. Applicability of these technologies tovarious classes of UAVs is evident (compact carriageand gun launch, as well as extra-planetary research).[4] Palmer, M., Forward Air Support Marine (FASM)Briefing, Reconnaissance & Surveillance Operation(RSO) Website (http://rso.saictuc.com/).[5] Small UAV Program Website, NAVAIR, 2003,(http://uav.navair.navy.mil/smuav/).[6] McDaniel, United States Patent Office, PatentNumber 1,905,298, 1933.[7] Jerry Jay's Wing and a Prayer Page -http://www.geocities.com/Athens/Ithaca/1397/.[8] ILC Dover Inc. Aerostat Development -http://www.ilcdover.com/Aerostats/aero.htm.[9] Priddy, United States Patent Office, Patent Number1,905,298, 1933.[10] Sebrell, United States Patent Office, PatentNumber 1,905,298, 1933.[11] Haggard, United States Patent Office, PatentNumber 1,905,298, 1933.8American Institute of Aeronautics and Astronautics

[12] Cadogan, D.P., Shook, L. S., Manufacturing andPerformance Assessments of Several Applications ofElectrotextiles and Large Area Circuits, MaterialsResearch Society, Boston MA, 2002.[13] Cohee, D. et. Al., Method of Making ThreeDimensional Articles From Rigidizable PlasticComposites. United States Patent Office, PatentNumber 5,651,848, 1997.[14] Allred, R., Scarborough, S., Cadogan, D, McElroy,P., UV Rigidizable Isogrid Structures, 43rdAIAA/ASME/ASCE/AHS/ASC SDM Conference,Denver, CO, 2002.[15] Lin, J.K., Sapna, G.H., Cadogan, D.P.,Scarborough, S.E., “Inflatable Rigidizable IsogridBoom Development,” AIAA-2002-1297, 43rdAIAA/ASME/ ASCE/AHS/ASC Structures, StructuralDynamics, and Materials Conference and ExhibitAIAA Gossamer Spacecraft Forum, Denver, CO: April22-25, 2002.[16] Cadogan, D.P,. and Scarborough S. E..“Rigidizable Materials for Use in Gossamer SpaceInflatable Structures,” AIAA-2001-1417, 42 ndAIAA/ASME/ ASCE/AHS/ASC Structures, StructuralDynamics, and Materials Conference and ExhibitAIAA Gossamer Spacecraft Forum, Seattle, WA: April16-19, 2001.[17] University of Kentucky Collge of EngineeringB.I.G. B.L.U.E. project -http://www.engr.uky.edu/bigblue/home.htm.9American Institute of Aeronautics and Astronautics