Shaw, J., Galloway, S., Norman, P., and Burt, G., "Aircraft Power and Propulsion Systems-Research Challenges and Opportunities for Electrical Systems," SAE Technical Paper 2012-01-2212, 2012, doi:10.4271/2012-01-2212.
NASA has compiled a set of research goals for five year periods starting 2015, 2020 and 2025 for three classes of future subsonic aircraft, N+1 (2015), N+2 (2020) and N+3 (2025). With the intention of progressively making reductions in noise emissions, greenhouse gas emissions, fuel burn and energy consumption at each of these points to achieve Technology Readiness Levels (TRL's) of between 4 and 6. In the last few years much progress has been made towards achieving these goals through the development of new technologies and designs. This paper assesses how the current More Electric Aircraft (MEA) design concepts are advancing to allow the near term, N+1 goals of reducing 32 dB of noise emissions, 60% of the landing and take-off (LTO) NOx emissions, 55% of cruise emissions and 33% saving of fuel burn and energy consumption, relative to single aisle B737-800, could be met and eventually surpassed. The paper also looks to future more advanced concepts and how they can enable the mid-term N+2 goals of a further 10 dB of noise to be cut along with 15% of emissions from flight and a further 17% reduction of fuel burn and energy consumption to be achieved, only for this generation of aircraft, relative to a twin aisle B777-200. The paper identifies areas where improvement is required to ensure that safety and reliability standards are maintained and that efficiency goals are met and surpassed. The paper then goes on to look at concepts employed in order to facilitate the removal of pneumatic and hydraulic systems, protection systems for the new more electric architecture and concludes by highlighting the technological and electrical systems integration challenges faced in the development of aircraft architectures to meet the N+2 goals by using the more/all electric aircraft design philosophy.