Preliminary Investigation of a Fishbone Active Camber Concept

Abstract

This paper introduces a novel airfoil morphing structure known as the Fishbone Active Camber (FishBAC). This design employs a biologically inspired compliant structure to create large, continuous changes in airfoil camber and section aerodynamic properties. The structure consists of a thin chordwise bending beam spine with stringers branching off to connect it to a pre-tensioned Elastomeric Matrix Composite (EMC) skin surface. Actuators mounted in the D-spar induce bending moments on the spine through an antagonistic pair of tendons in a manner similar to natural musculature systems. Several potential morphing configurations using this concept are introduced. The paper then focuses on a trailing edge morph wherein the compliant spine connects a rigid leading edge D-spar to a solid trailing edge strip. The motivation for exploring this novel morphing architecture is established through analytical aerodynamic comparison to the NACA 0012 airfoil with and without a discrete trailing edge flap. A prototype device is built to explore various aspects of manufacturing this concept, and to prove the large deflection capability of the FishBAC.