Electric aircraft represent a promising low-emission alternative to conventional fuel-powered aviation, driving the demand for lightweight and reliable electrical powertrain architectures. This study presents a design process for an electrical power system with an emphasis on the cabling system and battery in all-electric aircraft (AEA). Design considerations for the cabling system in power distribution architectures are discussed, including cable insulation material selection, conductor choice, sizing, and weight reduction methods. The influence of different system voltages and operating temperatures on cable weight is analyzed to identify optimal design tradeoffs. A comparison of polytetrafluoroethylene (PTFE) and perfluoroalkoxy (PFA) insulation materials, as well as aluminum and copper conductors, highlights their impact on weight and reliability, with PFA offering weight advantages under typical aerospace operating conditions. The batteries are sized based on the energy and power demands of a 90-seater AEA as a case study. After designing the components of the aircraft’s electrical power system, the electrical architectures are presented. Furthermore, a framework for evaluating the electrical power system architectures of AEAs is proposed, using two key criteria: reliability and weight. The weight of the electrical power system is then estimated based on aircraft performance requirements. The proposed framework provides practical guidelines for cable selection and architecture optimization in future AEAs.

The increasing adoption of hybrid and electric aircraft calls for the development of high-voltage cabling systems with superior thermal endurance and dielectric reliability. Understanding their aging behavior is essential for long-term performance in extreme environments. This study investigates the impact of thermal aging on the dielectric properties and breakdown strength of perfluoroalkoxy (PFA) insulated aircraft cables. Thermal aging tests were conducted which include exposing aircraft cables to a thermal aging profile for up to 500 h at 280° C. The dielectric properties, including relative permittivity, dielectric loss tangent (tan δ), and volume resistivity, were measured at room temperature using the Novocontrol Concept 80 broadband dielectric analyzer over a frequency range of 1 0 - 1 1 0 6 Hz. For AC breakdown strength evaluation, PFA insulation samples were tested under three electrode configurations: sphere-plane, sphere-sphere, and plane-plane. The results indicate that exposure to the thermal profile up to 500 h leads to a gradual decrease in relative permittivity and dielectric loss, accompanied by a noticeable increase in volume resistivity and a slight improvement in dielectric breakdown strength for all electrode configurations. This trend shall be attributed to the structural relaxation and annealing-like stabilization within the semicrystalline PFA matrix which may occur during the initial stages of thermal aging and leads to improved dielectric performance. Further investigations of long-term aging behavior and degradation mechanisms will be conducted in future work to better understand insulation lifetime under prolonged thermal stress.

Perfluoroalkoxy alkane (PFA) is a promising candidate for onbaord high-voltage cable insulation due to its superior dielectric properties, chemical resistance, and high thermal stability. Understanding the thermal aging behavior of PFA is essential for ensuring the long-term reliability of insulation materials in hybrid-electric aircraft, where high thermal fluctuations are common. This study investigates the chemical, structural, mechanical, and dielectric properties of PFA aged at 280 °C for up to 1000 h, simulating real-world aerospace operational environments. Results show that PFA undergoes chain scission and chemicrystallization in the early aging stages (0-480 h), leading to an increase in crystallinity. However, at longer aging times e.g. (>480 h), oxidative degradation becomes dominant, resulting in chemical and structural changes correlated with microstructural damage, including crack formation, tie-chain loss, and lamellar disruption. Dynamic mechanical analysis and tensile results show a significant decrease in molecular rigidity with a reduction in glass transition temperature (T_g), indicating a loss of material stiffness and a reduction in tensile strength (42.16%) and elongation (30.2%) after long term exposure (1000 h). Dielectric characterization demonstrates monotonic increase in dielectric constant (from 1.90 to 2.15), dissipation factor, and AC conductivity, attributed to the formation of polar oxidation products and defect-assisted interfacial polarization. The dielectric strength also decreases from 95.2 kV/mm to 87.1 kV/mm after 1000 h of aging. Molecular dynamics simulations (MDS) are also performed to study the temperature effect on PFA, revealing that at high temperatures, the PFA molecular structure is increasingly destroyed by thermal chain scission. These findings provide valuable insight into the degradation mechanisms governing PFA performance and contribute to evaluating its reliability as an insulation material for high-voltage cable systems in hybrid-electric aircraft.

Polyimide (PI) is extensively used in aerospace applications owing to its exceptional properties. However, exposure to harsh environmental conditions, including heat and humidity, can significantly affect its performance. Understanding the effects of aging on PI is important for ensuring its long-term reliability in aerospace systems. This research presents the impact of thermal oxidative aging and humidity on the dielectric performance of polyimide (PI). Aging was conducted at 250 C for 170 hours under controlled humidity conditions, facilitating thermal oxidative degradation and moisture absorption in polyimide. The results of Scanning Electron Microscopy (SEM) analysis revealed surface degradation in aged PI, characterized by micro-voids and cracks that facilitated moisture ingress into the bulk material. The aging process led to the formation of polar molecules, including moisture-induced hydroxyl groups, which enhanced the polarization ability and AC conductivity of PI. To analyze these conductivity changes, Jonscher's Power Law and the Almond-West formalism were employed. The fitting of AC conductivity data using these models provided insights into the frequency-dependent charge transport behavior in fresh and aged PI. The extracted parameters, including DC conductivity, crossover frequency, and relaxation time, demonstrated that aging resulted in increased charge transport and a shift in the frequency response. While the bulk resistivity decreased, the carrier density and mobility were notably enhanced, leading to an increase in leakage current density. At high electric fields (100 MV/m), the leakage charge density increased by 8.4% due to the aging process. These findings highlight the impact of both thermal oxidative and humidity-induced aging on the dielectric and microscopic properties of PI, which is essential for assessing its reliability in aerospace applications under harsh environmental conditions.