With the increase in demand for and reduction in costs of clean energy, wind turbines offer a very promising solution. However, to make offshore wind energy one of the preferred sources of clean energy, there is a need to bring down the levelized cost of energy (LCOE). The Segmented Ultralight Morphing Rotor (SUMR) project aims to achieve lower costs with the development of an extreme-scale 50-MW wind turbine having blade lengths greater than 200 meters. With the increase in rotor size, aero-elastic instabilities like flutter become a significant issue and begin to drive the design process. In this paper, we evaluate the flutter margin for a series of 13.2-MW wind turbine blade designs and compare to previous studies. Then, a semi-automated design tool called AutoNuMAD is introduced to explore the structural design space.