with electric primary propulsion, which would be an important certification pathway for larger, more complex aircraft that wish to use electric propulsion.
This investigation considers a balanced demonstration program that could be conducted for maximum impact, with controlled risk and cost. By targeting the performance and utility demanded of an early adopter market, this demonstrator program will kick off adoption of electric primary propulsion for aircraft and establish a much-needed operational basis for certification of larger, commercial aircraft. The demonstrator choices and technology concepts were selected from a blend of largely COTS motors and airframes to minimize development, and focus risk on the development of the hybrid SOFC-electric power system and integration into the airframe. This reduces the benefit that could be realized by electric propulsion, but showcases the impact of this approach on an “apples-to-apples” basis between the performance of capabilities of the unmodified aircraft and the selected demonstrator platform.
The estimated performance of the selected demonstrator concepts shows that it is quite possible to achieve a 50% or greater reduction in fuel costs for light aircraft. As fuel tends to be the largest direct operating cost associated with light aircraft (it can be half, and perhaps even more, depending on fuel price fluctuation), this can significantly reduce the operational cost for aircraft equipped with this new technology. Given the potential higher reliability of electric motors, other direct and indirect operating costs (e.g. maintenance cost) may be reduced as well. These substantial reductions in operating cost will appeal to early adopters in the light aircraft market, particularly if the payback period of the difference in up-front cost between the gasoline engine and the electric powertrain and power system is well within the aircraft’s operational lifetime. Such early adopters will enable more rapid accumulation of certification data to enable application of these technologies to larger, commercial aircraft, either as a means of primary propulsion or for onboard electrical power generation for other electronic systems.
Acknowledgments This work is funded under the NASA Aeronautics Research Mission Directorate Seedling Fund, administered by
the NASA Aeronautics Research Institute (NARI). The authors would like to thank NARI, including Michael Dudley, Koushik Datta, and Deborah Bazar, for their assistance and support throughout this effort.
References 1. M. Moore, K. Goodrich, J. Viken, J. Smith, B. Fredericks, T. Trani, J. Barraclough, B. German, M. Patterson, “High-Speed
Mobility through On-Demand Aviation,” AIAA 2013-4373, Aviation Technology, Integration, and Operations Conference, Los Angeles, CA, August 2013.
2. N. K. Borer, M. D. Moore, A. R. Turnbull, “Tradespace Exploration of Distributed Propulsors for Advanced On-Demand Mobility Concepts,” AIAA-2014-2850, AIAA Aviation, Atlanta, GA, June 2014.
3. N. K. Borer, M. D. Moore, “Integrated Propeller-Wing Design Exploration for Distributed Propulsion Concepts,” AIAA 2015-1672, AIAA SciTech, Kissimmee, FL, 5-9 January 2015.
4. M. Moore and B. Fredericks, “Misconceptions of Electric Propulsion Aircraft and their Emergent Aviation Markets,” AIAA 2014-0535, 52nd Aerospace Sciences Meeting, National Harbor, MD, January 2014.
5. Airbus Group, “Airbus E-Fan: the future of electric aircraft,” http://www.airbusgroup.com/int/en/innovation-environment/e- fan-the-electric-plane.html, accessed 13 May 2015.
6. M. Grady, “Pipistrel Introduces Alpha Electro,” http://www.avweb.com/avwebflash/news/Pipistrel-Introduces-Alpha- Electro-223852-1.html, accessed 13 May 2015.
7. G. Warwick, “NASA’s Electric-Propulsion Wing Test Helps Shape Next X-Plane,” Aviation Week & Space Technology, 24 August 2015.
8. J. Hemmerdinger, “Three ‘miracles’ required for mainstream electric-powered aircraft, says P&W,” http://www.flightglobal.com/news/articles/three-39miracles39-required-for-mainstream-electric-powered-aircraft-says- 399640/, accessed 13 May 2015.
9. ASTM International, Standard Specification for Leaded Aviation Gasolines, ASTM D910, 2015. 10. ASTM International, Standard Specification for Aviation Turbine Fuels, ASTM D1655, 2015. 11. AA Portable Power Corporation, “Hi-Power Li-Po Packs,” http://www.batteryspace.com/hi-powerli-popacks.aspx, accessed
13 May 2015. 12. Tesla, “Battery: Increasing Energy Density Means Increasing Range,”
http://my.teslamotors.com/roadster/technology/battery, accessed 13 May 2015. 13. Pipistrel Aircraft, “Taurus Electro,” http://www.pipistrel.si/plane/taurus-electro/faq, accessed 15 May 2015. 14. R. A. McDonald, “Establishing Mission Requirements Based on Consideration of Aircraft Operations,” Journal of Aircraft,
50(3) 741:751, 2013. 15. Federal Aviation Administration, “National Plan of Integrated Airport Systems (NPIAS), (2011-2015),” Report of the
Secretary of Transportation to the United States Congress, 27 September 2010.