Revisiting Wingtip Turbines for Performance Improvement and Emissions Reductions on Conventional and Hybrid Commercial Aircraft

Ongoing subsonic aircraft design work continues to demonstrate the potential of new concepts to meet the performance 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 and onboard system complexity. This enables aircraft to undertake more diverse missions, but comes at the cost of increased onboard electricity requirements. Recent work, summarized here, undertook conceptual engineering design and analysis work to investigate the viability of wingtip turbines to not only harvest energy from an aircraft’s wake to generate electricity, but also improve the performance of the aircraft by generating thrust (to reduce total system drag). Emphasis in this effort was placed on the Boeing 737 and the NASA SUbsonic Single Aft eNgine hybrid electric aircraft concept, and results summarized here suggest that mission fuel use could be reduced by >1.5% for the 737 and >3% for the SUSAN when wingtip turbines are used for thrust generation. When used for electrical power generation, the potential fuel savings for the 737 increase substantially to >7.2%, and >3.5% for the SUSAN configuration. Fuel savings offered by wingtip turbines can be used for payload or range extensions, with the trends being broadly consistent with those summarized above