On the matching between design specifications and payload-range efficiency of transport airplanes
Creators: name:  R. MARTINEZ-VAL 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: SYSTEM INTEGRATION
AERONAUTICS

description: Commercial aviation has evolved since pioneer times to become one of the most astounding technological achievements of industrial society. Its capacity and productivity are still growing and most air traffic predictions indicate a long-term increase, despite some vivid downturns, with a global passenger traffic expected to go up at a yearly pace around 5%. To encompass this history of success, airplane performances have also greatly improved over the last decades, mainly due to developments in key technological areas such as aerodynamics, propulsion, structures, avionics, materials, flight procedures, etc. The current scenario combines growing activity, environmental constraints and technological development. Many thousands of airplanes will be required in the next decades to replace obsolete aircraft and to offer suitable solutions to the flourishing market. On another side, airline routes, that define the airplanes to be built, are largely determined by the interaction of geographical, political, economic and social factors that provide the initial specifications for new designs: payload capacity (commonly, the number of passengers), range with a given payload, length of airport runways, and the like. Airplane design is a multidisciplinary activity involving various, progressively complex stages and numerous, conflicting specifications and requirements. In the conceptual design phase, albeit data and information are very scarce, the designer has to take many decisions that will deeply affect key variables and, thus, the final product. Two particular aspects have to be considered at such level: the design point; i.e., the selection of the wing loading and the thrust over weight ratio, to fulfil cruise, take-off, landing and second segment climb requirements, and the operating point, a specific payload-range pair within the foreseen payload-range diagram of the aircraft (see Fig. 1) to match the most demanded routes and to offer flexibility to serve many others. Obviously, both points must be compatible and have to be consistent with the future utilisation pattern of the aircraft. In the end, the design variables and the utilisation pattern should match each other to provide minimum operating cost and maximum payload-range efficiency. This last is defined as PRE= (PLR)/TF where PL stands for payload, R is range and TF is trip fuel in the route under consideration (see Fig. 2). The research proposed here describes this matching process, and how the design specifications and the design decisions affect the economy and performances of the aircraft. Figure 1. Sketch of payload-range diagram of a transport airplane, showing actual aircraft utilization (light grey) and maximum utilization (dark grey). Also shown are points corresponding to the conventional design point ?, and a reduced MTOW scenario ?. [1] Figure 2. Evolution of payload range efficiency of transport airplanes. Modified from [2] REFERENCES 1. Martinez-Val, R, Roa, J, Perez, E and Cuerno, C. Effects of the mismatch between design capabilities and actual aircraft utilization. Journal of Aircraft, Vol. 48, N 6, pp. 1921-1927, 2011. 2. Li, M. Conceptual design study for in-flight refuelling of passenger aircraft. PhD Thesis, Technische Universiteit Delft, Delft, The Netherlands, 13 April 2017. 3. Roskam, J. Airplane Design. Part I. Preliminary Sizing of Airplanes. DAR Corporation, Lawrence, Kansas, USA, 1985. 4. Nangia, R. Efficiency parameters for modern commercial aircraft. The Aeronautical Journal, Vol. 1110, n 1110, pp. 495-510, 2006. 5. Martinez-Val, R, Palacin, JF and Perez, E. The evolution of jet airliners explained through the range equation. Proc. IMechE, Part G, Journal of Aerospace Engineering, Vol. 222, G6, pp. 915-919, 2008. 6. Martinez-Val, R, Perez, E, Cuerno, C and Palacin, JF. Cost-range trade-off of intermediate operations of long range transport airplanes. Proc IMechE Part G Journal of Aerospace Engineering, Vol. 227, N 2, pp. 394-404, 2013. 7. Torenbeek, E. Advanced Aircraft Design: Conceptual Design, Technology and Optimization of Subsonic Civil Airplanes. Wiley, New York, NY, USA, 2013. 8. Global Market Forecast. Airbus, Blagnac, France, 2018.