Flutter analyses of the X-56 unmanned aerial vehicle within the AEPW-3 flight test working group

The X-56 is a Unmanned Aerial Vehicle developed and build by Lockheed Martin in 2013 with the intention to learn more about certain flutter phenomena and active flutter suppression. The UAV is of the flying wing type configuration, which is designed to be susceptible to Body Freedom Flutter due to low pitch inertia. In the third Aeroelastic Prediction Workshop lead by NASA, this UAV is the subject of investigation to do research within the Flight Test working group, in order to consolidate the tools used by each partner in the workshop, learn more about active flutter suppression, and share knowledge and experiences within the workshop. The Finite Element Model together with the outer mold line of the X-56 is used as provided by AFRL. Two level of fidelity analyses have been performed; a flutter analyses based on the Doublet Lattice Method as included in the commercial software ZAERO as well as the flutter analyses based on the Computational Fluid Dynamic analyses using the inhouse flow solver ENFLOW. The paper will describe and share the results for future comparison with the Aeroelastic Prediction Workshop.