Environmentally Focused Aircraft Study

The Environmentally Focused Aircraft (EFA) study investigated the potential to reduce the environmental impact of future regional aircraft by employing unconventional aircraft configurations and alternative mission profiles. ... [ view full abstract ]

The Environmentally Focused Aircraft (EFA) study investigated the potential to reduce the environmental impact of future regional aircraft by employing unconventional aircraft configurations and alternative mission profiles. The project was partly funded by the GARDN network and involved partners Bombardier Aerospace (BA), Pratt & Whitney Canada (P&WC) and the University of Toronto Institute of Aerospace Studies (UTIAS).

Increasing concern over the environmental impact of aviation is motivating efforts to reduce aircraft fuel burn more than ever before. The Advisory Council for Aeronautics Research in Europe (ACARE) has stipulated the goal of reducing CO2 emissions from aircraft by 50% by 2020, relative to a 2000 baseline. Achieving this ambitious goal will depend on the cumulative impact of various advanced technologies including advanced propulsion architectures, composite materials and laminar flow aerodynamics, along with potentially unconventional airframe configurations. Conventional airframe configurations are now well matured, leaving limited scope for improvement. The adoption of unconventional configurations may allow a step-change in aircraft efficiency and associated environmental impact. Furthermore, the cruise speed and altitude of today’s commercial aircraft is determined largely by economic rather than environmental concerns. Varying cruise speed and altitude may provide additional reductions to environmental impact.

The EFA study generated aircraft solutions for a range of conventional and unconventional aircraft configurations such as the Strut-Braced Wing (SBW), Joined-Wing (JW) and Blended-Wing Body (BWB). Cruise speed and altitude were also considered as variables, allowing airframe and mission profile to be optimized simultaneously. Aircraft solutions were generated using a Multi-Disciplinary Optimization (MDO) toolset, allowing optimum solutions to be found within prescribed design constraints, by allowing a numerical optimizer to control key aircraft design parameters. A number of different design objectives such as operating cost, fuel-burn and climate impact were considered, and the trade-offs between them investigated. A dedicated climate impact model was developed as part of the project to quantify the climate impact of all aircraft emissions, rather than CO2 alone.

All aircraft solutions were sized to meet the performance requirements of a known reference aircraft, allowing a direct comparison with today’s regional aircraft products. Various advanced technology assumptions were then incorporated including advanced propulsion technology, structural and systems mass savings and laminar flow drag reductions. Finally, the unconventional configurations were applied along with the other advanced technologies. This approach allowed the incremental benefit of each individual technology to be identified, while also resulting in an assessment of the cumulative reduction in environmental impact that can be achieved over today’s baseline.