2016 AE grad recognized for novel propeller blades
Brandon L. Litherland, BS ’16, is the recipient of the NASA Exceptional Engineering Achievement Medal for his outstanding innovation in the design of conformal folding propeller blades for the X‐57 Maxwell flight demonstrator.
Watch a video of a wind tunnel test. The video is courtesy of NASA and ESAero (Empirical Systems Aerospace).
Litherland said the X-57 Maxwell uses relatively small diameter, high-lift propellers to accelerate the air over the wing and augment lift at low speeds. In doing so, the aircraft is able to maintain the same stall speed as the baseline Tecnam P2006T with a cruise-optimized wing having only 42 percent of the baseline wing area.
“At higher speeds, the high-lift systems are no longer needed and, if left exposed to the freestream, the 12 high-lift propellers would greatly increase the total drag and disrupt flow over the wing. To avoid these issues, the high-lift propeller blades stow against the nacelle when not in use. I developed a method of designing propeller blades in such a way that allows them to fold about a single axis and conform to the attached nacelle while effectively maintaining the performance of the non-folding propeller design,” Litherland said.
Litherland said he was working as a NASA Pathways Student for Langley Research Center while he was an undergrad at the University of Illinois in the Department of Aerospace Engineering.
“At the time, I was primarily working on the Leading Edge Asynchronous Propeller Technology distributed electric propulsion study which later became SCEPTOR and then X-57 Maxwell,” he said. “After graduating, I converted to a civil servant in the same group, the Aeronautics Systems Analysis Branch, where I continued my work as a vehicle configurator designing and analyzing concept aircraft.”
He began working remotely on a master’s degree at the Georgia Tech Aerospace Systems Design Laboratory under Dimitri Mavris. He did most of the foundational work on the folding, conformal propellers in 2016 at Langley Research Center, publishing a paper on the general method at Aviation 2017. As a result of that work, he was named the NASA Langley Research Center Aeronautics Systems Analysis Branch 2017 Innovator of the Year.
Litherland continued to study and enhance the folding blade methods and later published a performance comparison between folding and non-folding blades.
In the spring of 2019, Litherland was accepted into the NASA Langley Research Center advanced degree program which funds part-time graduate education for civil servants.
“With this, I am continuing to pursue my master’s degree with an expected graduation in spring 2021. I’m only taking one course at a time due to work, family, and remodeling my house,” he said.
Currently, Litherland is working on the X-57 as the lead for the aerodynamic reference outer mold line vehicle sketch pad model, a version of which was released as a common research model this year. He is also working on X-57 performance and design, primarily on the distributed electric propulsion high-lift system but also on cruise propulsion, mission analysis, and dynamics. In addition, he is working with others at NASA’s Aeronautics Systems Analysis Branch on a rapid conceptual development and analysis environment and creating an online training program for open vehicle sketch pad to provide a publicly available resource for tutorials and guidance on best practices.