The design of wings with morphing capabilities is known to give aerodynamic benefits. These aero-dynamic benefits come from both the use of hinge-less surfaces and the greater adaptability to flight conditions. This paper describes the structural design of a twisting wing to be used for an unmanned air vehicle (UAV) and presents finite element analysis and experiment results. This is part of a research project carried out at the University of Southampton in which one of the goals is to compare different novel wing designs and technologies to determine which one of them gives the best performance. The twisting capability provides roll control without hinged surfaces hence providing aerodynamic improvement. The wing is manufactured using polystyrene foam and is cut out of block of this material using a hot wire machine. In order to link this foam structure to a main spar, ABS plastic inserts were manufactured using a 3D printer. The mechanisms used to actuate the wing are also made from this material. A full scale UAV wing has been manufactured and tested in order to compare with FEA results.