Robust Gas Turbine and Airframe System Design in Light of Uncertain Fuel and Prices

Abstract

This paper presents a study that numerically investigated which cruise speed the next generation of short-haul aircraft with 150 seats should fly at, and whether a conventional two- or three-shaft turbofan, a geared turbofan, a turboprop, or an open rotor should be employed to make the aircraft’s direct operating cost robust to uncertain fuel and carbon () prices in the year 2030, taking the aircraft productivity, the passenger value of time, and the modal shift into account. To answer this question, an optimization loop was set up in MATLAB consisting of nine modules covering gas turbine and airframe design and performance, flight and aircraft-fleet simulation, operating cost, and optimization. If the passenger value of time is included, the most robust aircraft design is powered by geared turbofan engines and cruises at Mach 0.80. If the value of time is ignored, however, then a turboprop aircraft flying at Mach 0.70 is the optimum solution. This demonstrates that the most fuel-efficient option, the open rotor, is not automatically the most cost-efficient solution because of the relatively high engine and airframe costs.