Technology selection for holistic analysis of hybrid-electric commuter aircraft

Abstract

Electric powertrains have different characteristics than conventional powertrains with combustion engines and require unconventional aircraft designs to evolve their full potential. Therefore, this paper describes a method to identify potential aircraft designs with electrified powertrains. Promising technology options in the fields of powertrain architecture, aerodynamic interactions, onboard systems and operating strategies were collected by the project partners of the LuFo project GNOSIS. The effect of the technology options on a commuter aircraft was evaluated in terms of global emissions ($$\hbox {CO}_{2}$$ CO 2 ), local emissions ($$\text {NO}_{\text {X}}$$ NO X and noise) and operating costs. The evaluation considers an entry into service in 2025 and 2050 and is based on the reference aircraft Beechcraft 1900D. Literature review and simplified calculations enabled the evaluation of the aerodynamic interactions, systems and operating strategies. A preliminary aircraft design tool assessed the different powertrain architectures by introducing the two parameters ’power hybridization’ and ’power split’. Afterwards, compatible technology options were compiled into technology baskets and ranked using the shortest euclidean distance to the ideal solution and the farthest euclidean distance to the worst solution (Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method). An analysis of the CS 23 regulations leads to a high-wing design and excluded the partial turbo-electric powertrain architecture with the gas turbine in the aircraft tail. For 2025, a partial turbo-electric powertrain with two additional electric driven wingtip propellers was selected. A serial hybrid powertrain, which uses a gas turbine or fuel cell in combination with a battery, powers distributed electric propulsors at the wing leading edge in 2050. In both scenarios, the aircraft design includes an electric environmental control system, an electric driven landing gear and electro-hydraulic actuators for the primary flight control and landing gear.

A simplified automated approach for a preliminary safetyassessment of distributed electric and hybrid propulsionsystems

“…As a baseline of further examinations a reference aircraft design has been established within GNOSIS, which is basically the redesign of the existing Beechcraft 1900D aircraft. However, due to an initial safety assessment the low wing configuration has been changed into a high wing design [38] and has generally been introduced to enable comparison to the subsequent design variants. The reference design has a conventional powertrain design, but is included in the following evaluation in order to validate the approach presented and to highlight the fundamental difference in complexity of failure scenario analysis between conventional and disruptive propulsion architectures.…”

Influence of Electric Wing Tip Propulsion on the Sizing of the Vertical Stabilizer and Rudder in Preliminary Aircraft Design

“…Based on the outcome of a market analysis, the Beechcraft 1900D was chosen as the reference aircraft. According to the results of an initial technology identification and selection process (with respect to technologies associated with aircraft propulsion system electrification), a partial turboelectric propulsion system featuring two gas turbines supplemented with two electrically driven propellers on the wing tips for a reduction in induced drag was selected as the most promising concept for the evaluation in a year-2025-scenario [21]. The basic assumption in the technology selection process was that an aircraft with electrified propulsion systems needs to fulfil identical mission requirements as current conventional aircraft in terms of its range, speed and passenger capacity in order to be recognized as a viable alternative.…”

“…Each electric motor is directly coupled via cables to its related generator, which converts part of the shaft power of the gas turbine, sparing the use of large electric energy storage devices. This configuration enables two wiring options, as suggested by [21]. An "on-wing wiring" approach, where the gas turbine on one wing is coupled to the electric motor on the same wing and a "cross wiring (x-wiring)" approach where the gas turbine is coupled to the electric motor on the opposite wing.…”

Systems Integration Framework for Hybrid-Electric Commuter and Regional Aircraft

“…Zumegen et al [31] investigate the impact of powertrain architecture, aerodynamic interactions, systems technologies, and operating strategies on a commuter aircraft. They quantify the effect of systems technologies such as electric taxiing and electro-hydrostatic primary flight control actuation, among others, on CO 2 , NO x , energy costs, and noise using available literature and simplified calculations.…”