In conjunction with the Air Force Institute of Technology AFIT and the Air Force Research Laboratory AFRL, the University of Michigan has designed and is currently building a remotely piloted aircraft RPA experimental high altitude long endurance X-HALE aircraft to collect non-linear aeroelastic data to validate HALE aircraft design codes developed by academia, industry, and the federal government. While X-HALE is representative of HALE aircraft, the manufacturing and evaluation techniques are applicable to larger full size HALE aircraft such as the concepts being developed under Defense Advanced Research Projects Agency's DARPA's Vulture program. This paper documents the development of the X-HALE model to date including a history of the programmatic decisions, basic model configuration, geometric considerations, sensor and system architecture, and manufacturing challenges. Lessons learned from the prototyping include the evolutionary growth of X-HALE's joiner blocks and the manufactur