Sustainable aviation is a key objective in reducing the environmental impact of air travel. Reduction of greenhouse gas emissions can be accomplished through increased efficiency in aircraft design. One approach to improving efficiency is the application of High Aspect Ratio (HAR) wings, which offer enhanced aerodynamic performance. However, compared to conventional wing designs, HAR wings experience an increased dynamic response due to external disturbances, resulting in higher wing loads. The UPWing project “Novel Control Technologies” aims at reducing these wing loads by applying manoeuvre and gust load alleviation technologies. As part of this effort, a wind tunnel model is being developed to investigate different methods for gust load alleviation (GLA) in transonic cruise speed conditions. The model will have 1.47 m semi-span, at a scale factor of 15.3, and utilise fast actuating control surfaces to alleviate the gust loads. This paper, as part of the STS420 programme, will provide an overview of the design and development of the GLA wind tunnel model, focusing on the wing structure itself and the (internal) flap actuation mechanism. The main challenges associated with the design and development of the GLA wind tunnel model is to create a flexible model that can withstand large bending deformations, equivalent to 17% of the semi-span, while maintaining structural integrity. Additionally, the model must integrate various types of instrumentation, such as Kulites for dynamic pressure measurement, accelerometers, and strain gauges. The design must also accommodate a hydraulic actuation mechanism for each of the three flaps, that is sufficiently fast (compared to the wing eigenfrequency) and able to overcome the moments generated by the control surfaces in transonic test conditions, all within the limited available space inside the wing. Further, these actuation mechanisms should have minimal impact on the stiffness of the wing and not compromise the wing’s structural integrity.