Development of a Rudderless Aeroelastic Fin Technology

摘要

This pro ect aims at developing a gapless and rudderless aeroelastic fin technology GRAF for the lateral directional control of air vehicles.The ob ective of the study is to design a light weight hinge-less and gapless fin structure that will achieve the same stability and control authority characteristics of conventional configurations, I.e. those comprising a hinged rudder.The current paper presents the details of a GRAF development including conceptual and structural design and performance analysis, nlike a conventional stiff fin with a rigid hinged rudder, the GRAF empennage is designed as a unitized piece of flexible structure integrated with a compliant TE section acting as a morphing control surface. The aeroelastic fin operates essentially through span-wise twisting this is achieved by initiating a rotation of the main beam and cambering the TE fin sections via a new actuation concept, denoted as L Shaped Stringer LSS, which is here presented in detail. Consequently the twist will increase the torque due to aeroelastic coupling.The design guidelines and operation principles of a GRAF device are presented and discussed. It is here demonstrated that a proper aeroelastic tailoring of the control surface provides benefits both in terms of directional stability and control nevertheless in order to exploit those advantages the aeroelastic control surfaces must be significantly more compliant than traditional empennages. This implies that the flutter and divergence margins associated to the GRAF are much tighter than in conventionally designed empennages.