Aeroelastic tailoring for improved UAV performance

Abstract

This paper describes how aeroelastic tailoring, in concert with optimal composite material design, might be applied to a new generation of Unmanned Air Vehicles (UAV's) to increase range and improve lateral control effectiveness. UAV development provides a new venue for design because it encourages creativity by removing some design constraints. This paper reviews: 1) design opportunities provided by UAV missions; 2) and, aeroelastic tailoring features mat lend themselves to improved performance. The aeroelastic features discussed in this paper are: lateral control and, reduced induced drag. Our studies show that aeroelastic tailoring can increase the control reversal speed of swept wings and that different laminate designs are needed depending on whether leading edge or trailing edge controls are used. We also show that induced drag can be controlled by laminate tailoring and that in some cases drag can be reduced if the wing structural aspect ratio is low, about AR=3. PurposeUnmanned Air Vehicle (UAV) development has been identified as a future development area with potentially revolutionary outcomes. 1 Two highlighted areas for UAV's with special technological challenges are vehicles to suppress air defenses and improved high altitude observation and weapon carrying aircraft.The purposes of this paper are to • describe design opportunities provided by UAV missions and the need for increased performance• summarize the effects of controlled aeroelastic interaction with advanced composite aircraft wings that aeroelastically couple structural flexibility and wing control surfaces to improve airplane maneuverability and reduce induced drag. UAV benefits and attributesTechnological capability always runs far ahead of application to real aircraft because of the need to thoroughly consider the trade between system performance benefits from the technology and the cost of the technology. As a result, some technology can languish for years before it sees an application to a real air vehicle. Today we have few opportunities to test new technology on real flight vehicles; this situation is unlikely to change in the future. This means that worthwhile technology will take a long time to mature. On the other hand, UAV's offer low cost vehicles that can benefit from new technology.UAV literature (and that of their predecessors, the Remotely Piloted Vehicles or RPV's) is extensiveê xtending over the past few decades. 5 " It is not our purpose to review the history of UAV or RPV development since UAV's and RPV's have a long history; numerous regularly scheduled conferences have been held world-wide during the past few decades. Basic technology for RPV's is well-developed and manufacturers world-wide offer a variety of products.On the other hand, recent interest in military UAV's triggered by advances in computer information technology and navigation has opened up new possibilities.A review of the recent literature reveals many claimed UAV benefits. These include:1. Reduced human risk with increased capability for dangerous missi...

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