Description: Ongoing work in ultra-efficient subsonic air-vehicles clearly shows the potential of evolutionary and revolutionary concepts to meet the performance and emissions goals of future aircraft. Propulsion and auxiliary system electrification plays a critical role in achieving these goals since it enables the reduction of fuel burn, emissions, and onboard system complexity, all the while enabling aircraft to undertake more diverse missions; however this comes at a cost - namely the need to provide sufficient electricity with minimal weight and size penalty. For example, batteries have, and will have for the foreseeable future, low energy density compared to aviation fuels or hydrogen, which means that aircraft designers (or integrators in the case of upgrading/adapting legacy aircraft) must trade the performance benefits that electrification brings with the challenges of integration. The proposed effort led by Continuum Dynamics, Inc. seeks to address these issues by developing a system of retrofittable electrical generators (wingtip turbines) that not only harvest energy from an aircraft's wake, but also improve the performance of the aircraft by generating thrust (to reduce total system drag). Prior theoretical and experimental work established the technical feasibility of wingtip turbines, and Phase I seeks to undertake the preliminary design of an optimized turbine and quantification of net performance trades (e.g. electricity generation, fuel, carbon and weight savings) and maintenance concerns. Phase II would see the more detailed system design and possible hardware development and testing to address NASA's aircraft emissions reduction and performance improvement needs.

Benefits: The proposed effort directly supports several NASA projects by providing a technology to directly improve aircraft performance while reducing emissions. Specific projects include: the Sustainable Flight National Partnership projects, the Advanced Air Vehicle Program's Advanced Air Transport Technology project developing the next generation of subsonic and supersonic civil aircraft; as well as the Transformative Aeronautics Concepts Program's Convergent Aeronautics Solutions and Transformational Tools and Technologies Projects.The proposed effort will produce a wingtip turbine design methodology that can be applied to new and legacy aircraft to simultaneously improve vehicle performance and emissions, while generating additional electricity onboard. Significant commercialization is anticipated by licensing the methodology to aircraft and electric propulsion/generator manufacturers, and aircraft owners/operators.