FEASIBILITY STUDY OF A HYBRID BUSINESS TURBOPROP
Creators: name:  R. MARTINEZ-VAL 
name:   P. LOPEZ 
name:   D. DORAL 
name:   M. MADINABEITIA 
name:   V. MUNOZ 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: AERONAUTICS
FUTURE APPROACH

description: Abstract The present study concentrates on the feasibility of a business hybrid turboprop, following the current trends for more electric airplanes to combat climate change and reduce operating costs and noise. Although the propulsion is fully electric, as shown in Figure 1, an important fraction of the electrical energy required for the flight is produced by a gas turbine generator located inside the fuselage tail cone. The rest of the energy comes from batteries. The main issues considered are the degree of hybridization (i.e., the ratio between the energy stored in batteries to the total needed for the flight), and the influence of range and battery technology level in the feasibility of the concept. The chosen configuration is that of a three lifting surface airplane, which is taken as a base known design. The analysis includes modifications of the drag polar, maximum lift coefficient and other key features. Because of the power demand in various performances, three electric motors (linked to their respective propellers) are needed: two of them at the wing tips and a third set located at the T cross of vertical and horizontal tailplanes. Battery mass increases dramatically with hybridization degree and range. With the current technology level, it is unfeasible to go beyond hybridization above 0.35 and ranges longer than 1000 km (see Fig. 2). Within these limitations and scenario, the maximum take-off weight is kept in reasonable values. If battery technology (energy stored density) improves as foreseen, the hybrid airplane could fly up to ranges of around 3000 km, at reduced DOC and performing much more environmentally friendly than current turboprops. Figure 1. Conventional (left) and hybrid (right) aircraft configurations of a business turboprop. Turboprop engines in orange; electric motors in blue and turboshaft generator in green. Figure 2. Battery mass required as a function of hybridization degree, ?, and range, L, with current technology level. Some references used to prepare the abstract Brelje, B.J. and Martins, J.R.R.A. Electric, hybrid, and turboelectric fixed-wing aircraft: A review of concepts, models, and design approaches, Progress in Aerospace Sciences, vol. 104, pp. 119, 2019. Dean, T.S., Wroblewski, G.E. and Ansell, P.J. Mission Analysis and Component-Level Sensitivity Study of Hybrid-Electric General-Aviation Propulsion Systems, Journal of Aircraft, vol. 55, no. 6, pp. 24542465, 2018. EASA, EEA and EUROCONTROL, European Aviation Environmental Report 2019. Isikveren, A.T., Kaiser, S., Pornet, C. and Vratny, P.C. Pre-design strategies and sizing techniques for dual-energy aircraft, Aircraft Engineering and Aerospace Technology, vol. 86, no. 6, pp. 525542, 2014. Roskam, J. Airplane Design. Part I. Preliminary Sizing of Airplanes. Ottawa, Kansas, USA: Roskam Aviation and Engineering Corporation, 1985. Roskan, J. Airplane design. Pt. 6. Preliminary calculation of aerodynamic, thrust and power characteristics. Ottawa, Kansas, USA: Roskam Aviation and Engineering Corporation, 1987. Snyder, M.H. and Zumwalt, G.W. Effects of wingtip-mounted propellers on wing lift and induced drag, Journal of Aircraft, vol. 6, pp. 392397, 1969. Suder, K. Overview of the NASA Environmentally Responsible Aviation Projects Propulsion Technology Portfolio, pp. 123, 2012. Thomson, R., Sachdeva, N., Nazukin, M. and Martinez, N. Aircraft Electrical Propulsion The Next Chapter of Aviation? Think: Act, pp. 132, 2017. Torenbeek, E. Advanced Aircraft Design: Conceptual Design, Technology and Optimization of Subsonic Civil Airplanes. Wiley, New York, NY, USA, 2013.