## 1 Introduction and Literature Survey
### Adaptive Wing  
The ability of a wing to change its shape during flight has been a significant area of interest over the years for both researchers and aircraft designers. Moreover, the adaptive wing can be used to further optimize an aircraft's flight throughout all phases of its typical flight mission by providing significant drag reduction during the climb, descent, and cruise regimes. Flight tests have demonstrated that a 20% reduction in the overall drag of an aircraft leads to an 18% reduction in fuel consumption [11]. The design of the active aeroelastic wing was based on modifying the wing of an existing aircraft in order to make it lighter and more flexible, thereby increasing the aircraft's dynamic performance. In 1980, with developments in morphing aircraft already a goal for both academia and major aeronautics companies, Boeing modified an existing military aircraft with an adaptive wing structure able to alter its curvature during flight, thereby optimizing its aerodynamic performance for various flight conditions [12]. The Adaptive Wing project, carried out by EADS (European Aeronautic Defense and Space Company), Airbus, Daimler, and DLR (German Aerospace Center) [13], developed a compliant wing structure that could redistribute external aerodynamic forces so that it could be morphed in predetermined areas while remaining rigid to deformation in other areas. In 2001, researchers from NASA Dryden Flight Research Center conducted several flight tests on a UAV equipped with inflatable wings, whose curvature could be modified by adjusting the pressure input. Other efforts in adaptive wing design have resulted in a variety of morphing concepts, as reviewed by [PERSON] et al. [14], who combined conventional flap devices with morphing technologies and presented promising aerodynamic gains. Since the early 2000s, adaptive wings have been studied at our Laboratory of Applied Research in Active Controls, Avionics and AeroServoElasticity (LARCASE) at the Ecole de technologie superieure (ETS). The team has studied adaptive wing technologies in two large-scale projects of the Consortium of Research and Innovation in Aerospace in Quebec (CRIAQ). Each of these projects has led to the design and manufacturing of prototypes and their experimental wind tunnel tests. Both projects, called CRIAQ 7.1 and CRIAQ MDO 505, were led at ETS in collaboration with Bombardier, Thales, NRC-IAR, and Ecole Polytechnique in Canada. In the CRIAQ 7.1 project [15; 16; 17], the deformation of the upper surface of a morphing wing was conducted using \"Smart Material Actuators\" (SMA) to improve and control the laminarity of the flow past a morphing wing in order to obtain drag reductions of up to 40%. The resulting deformation made it possible to delay the flow transition on the wing. The CRIAQ MDO 505 project [18; 19; 20] was to design and validate a morphing wing with a morphing aileron capable of delaying the flow transition at the upper surface of the wing. The prototype was equipped with four electrical actuators to change its upper surface shape. This concept was experimentally validated in the NRC-IAR wind tunnel. In this article, we developed a multidisciplinary methodology that can consider the interactions between structures, actuators, and aerodynamics. This methodology is capable of finding the geometry of an airfoil and its internal structure, which allows its shape to be changed for aerodynamic performance maximization. This research covers the study of a new adaptive wing prototype for the UAV S45 Balaam. The main objective of this adaptive wing is to promote large laminar regions on its surface, thereby reducing drag over the cruising flight phase. A prototype wing with an adaptive leading edge and upper surface was developed for this study. The flow response at the surface of the prototype wing was measured with an aerodynamic scale. The adaptive wing prototype was manufactured in-house using polymer, wood, and aluminum structures and rapid manufacturing techniques.