Michele De Gennaro

A preliminary analysis of aircraft refueling using liquid hydrogen (LH2) for a future short–medium-range aircraft is presented. The focus is on how selected refueling parameters influence pressure buildup and the release of boil-off gas (BOG), in order to establishing guidelines towards efficient refueling. The flow physics uses a 0-D multi-phase lump model, which accounts for the effects of the injected LH2, BOG release, heat fluxes and phase changes. Refueling is controlled by volumetric compression during the filling, and relaxation afterwards. Mass-flow profile and refueling protocol have little influence on the amount of BOG vented (~1%), but control the duration of the process, with variations close to 50%. Low initial pressure can significantly reduce the amount of BOG.

The aviation industry faces significant challenges in achieving climate neutrality by 2050, requiring a transition to advanced propulsion technologies and energy storage systems. This chapter examines the role of battery technologies in enabling electrified aircraft, assessing the current state-of-the-art battery systems, certification standards, and key performance indicators. It explores full-electric, hybrid-electric, and more-electric aircraft architectures, evaluating their feasibility across market segments and projecting battery performance requirements, the airborne battery market, and emission reductions through electrification by 2050. Case studies from ongoing European projects, such as HERA and HECATE, alongside industrial programs like Heart Aerospace’s ES-30 and ATR-EVO, are also discussed. Additionally, a structural battery concept is presented as a disruptive innovation for multifunctional energy storage, highlighting its potential to achieve higher energy densities compared to conventional integration concepts. The findings indicate that while battery technology advancements are critical for decarbonizing aviation, hybrid-electric and more-electric architectures will contribute approximately 3.5% to total emissions reductions. Though modest, this impact represents about 10% of the emissions reductions expected from technological developments by 2050. Future progress in safe, high-energy–density batteries and certification frameworks will determine the pace of electrification in commercial aviation, shaping the industry’s long-term sustainability.

This paper aims at presenting the results of the CleanSky 2 European project IMPACT (GA no. 885052), granted under the Large Passenger Aircraft Integrated Technology Demonstrator (LPA-ITD), aiming at optimizing the rear-end design for the next generation Short and Medium Range (SMR) A320-like aircraft. Specifically, the project has investigated a Forward Swept Horizontal Tail Plane (FSHTP) enhanced with a Leading-Edge eXtension (LeX) device. The activities have focused on the optimisation of the horizontal stabilizer, accounting for the coupled aerodynamic, aeroelastic and, for the first time, icing behaviour. The optimal solution provides significantly better lift performance of the tailplane (i.e. up to 12.4% increase in C_L), limiting the drag penalty to below 1.0% in cruise condition (i.e. between 0 and 2 degrees of Angle of Attack).