Design and Trajectory Optimization of a Morphing Wing Aircraft John P. Jasa * University of Michigan, Ann Arbor, MI, USA John T. Hwang † NASA Glenn Research Center (Peerless Technologies Corp.) Cleveland, OH, USA Joaquim R. R. A. Martins ‡ University of Michigan, Ann Arbor, MI, USA Adding morphing wing technology to aircraft could drastically reduce the fuel burn required to com- plete a certain mission. This gain comes from the wing being able to adapt to become optimal for the desired flight condition. For maximal benefit, we must design the wing, morphing inputs, and mission trajectory simultaneously. In this work, we perform gradient-based aerostructural optimiza- tion for a morphing Common Research Model wing while optimizing its nominal design, morphing twist across its mission, and its altitude profile. Using a morphing optimization approach that simul- taneously optimizes the mission and design, we find a 0.2 to 0.7% fuel burn decrease compared to a non-morphing design optimization, where the benefit increases with range. We also compare the fully coupled optimization approach with a surrogate-based approach to determine if we can simplify the optimization problem while still arriving at the optimal result. We find that the surrogate-based approach finds an optimum within 1.5% of the optimum obtained from the fully coupled approach and that the difference is smaller for smaller ranges. I. Introduction Wing morphing is not a new concept. The Wright Brothers utilized morphing wings to control their famous Wright Flyer in 1903. Early work on the subject back in the 1980s suggested applications in aerodynamics [1, 2], radar observability [1], and survivability [3]. Some modern work has focused on variable camber wings [2, 4, 5] and aerostructural optimization of morphing wing aircraft [6, 7, 8, 9, 10, 11]. Fundamentally wing morphing gives the wing designer more freedom by allowing the shape to change throughout the flight. However, the ability to alter the shape begs the question: what shape should it be? Burdette et al. addressed this question using a traditional multipoint approach and showed that there was potential for 2.58% fuel burn savings over a typical mission when morphing was applied to the NASA Common Research Model (CRM) concept [9]. They formulated their multipoint optimization objective as the average fuel burn, computed using the Breguet range equation, over a 7-point stencil. The stencil was selected to be representative of the cruise conditions seen on a reference mission for the aircraft they considered. In their work, the aerostructural analysis was done using a coupled Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) and finite elements analysis (FEA) model that was computationally expensive. Additionally, computing the objective and constraints required 9 calls to the high-fidelity models (7 point stencil for cruise performance, plus 2 load conditions). Burdette et al. later analyzed mission performance of a morphing wing aircraft by constructing a surrogate model based off high-fidelity * Ph.D. Candidate, Department of Aerospace Engineering, AIAA Student Member † Research Engineer (contractor at NASA GRC), AIAA Member ‡ Professor, Department of Aerospace Engineering, AIAA Associate Fellow 1