Aeroelasticity of Nonconventional Airplane Configurations-Past and Future

Abstract

At the end of the e rst century of manned, powered e ight, it is worthwhile to look backward to understand how innovation in airplane design required developments in aeroelasticity and how aeroelasticity has played a role in shaping the e rst 100 years of aircraft design. The insights gained will help to predict how and where aeroelasticity and aeroservoelasticity will ine uence the future development of efe cient, more capable, innovative air vehicles, and dee nethe needs fortechnology and tools to enable this future. By dee nition, all new aircraft begin as unconventional to a certain extent. Designs that never see universal use remain curiosities, but still help our questforbettervehiclesandguidethedevelopmentofanalysis, design, and testing tools. Innovative, nontraditional designsaffected by aeroelasticconsiderations haveincluded obliquewing aircraft, forward-swept wing aircraft,Xwings,e ying wings, andlargejoined wings. Designsthat wereunusually innovativeat thetimeoftheirintroduction but later became widespread include the swept-back wing jet, the T-tail, and the e y-by-wire control cone gured vehicle. Control and exploitation of aeroelasticity depends on the continued development of new materials, new structuralandaerodynamicconcepts,sensors,actuators,andactivecontroltechniques.Suchdevelopmentsmustbe accompanied by properintegratedanalysis/designtools,and,most importantly, by thesamehumaninquisitiveness and creativity that has driven aircraft design for over a century. This paper uses the history of nonconventional airplane cone gurations to review some of the steps taken during the past century to establish aeroelastic effects as integrated design features that must be anticipated, controlled, and exploited. The paper goes on to discuss the potential impact of past lessons on emerging airplane cone gurations currently in various stages of study and development.