LUBGEAR aims at demonstrating gear design solutions which can withstand off-design conditions in geared turbofans without additional means (secondary/auxiliary lubrication). Those solutions combine 1) optimized gear geometry providing low power loss conditions; and 2) Surface and material combinations providing low friction. The solutions aim at reducing friction losses and frictional heat, leading to reduced temperatures and risk of scoring. This will allow producing gears which do not face catastrophic damage even under loss of lubrication in off-design conditions. An investigation of new enabling technologies regarding off-design conditions will be carried out in simulation and experiment at contact level (TRL2). The combination of material systems (roughness, coating and hardening), contact load, sliding speed, rolling speed, lubricant type and lubricant supply will be considered through a Design of Experiments, allowing LUBGEAR to create a unique database and extend contact modelling tools. Gear Design Optimisation takes into account the results from contact level and derives solutions coming from geometry, material systems, operating conditions and passive lubrication. A demonstration of the most promising design and technology solutions for gears will be validated in an experimental component test rig at TRL3 level. Gear modelling addresses the predictive design of off-design conditions. LUBGEAR project gathers 4 strategic partners based on a multidisciplinary approach combining uniquely engineering, tribology, mechanics and advanced chemistry. This will allow developing a gear design with an increase of over 100 % in scoring load and a reduction of over 50 % of frictional losses resulting in remarkable improvements in loss of lubrication conditions. LUBGEAR will assess the benefits of different gear designs including gear geometry, new material systems and passive lubrication technologies in reaching the efficiency and load capacity required for gearboxes.

To achieve climate neutrality in aviation by 2050, hydrogen powered aircraft propulsion can be key. For this, several challenges need to be tackled such as thermal management and heat rejection of fuel cells in the aircraft. For each watt of electricity produced by a fuel cell, one watt of waste heat is generated. Recuperating it to further use would be indeed an asset. The exFan project will target such innovation by including a ducted heat exchanger in the nacelle of the propulsion system. It will use the ram jet effect, called also "Meredith effect" (ME) to generate thrust from waste heat. The design of a lightweight heat exchanger and the recovery of waste heat using the ME are promising topics further investigated in detail here. The exFan system will be included in a geared electric fan propulsion system of mega-watt class powered by hydrogen fuel cell technology. The heat exchanger will be a bionic design duly surface finished to hinder particle accumulation, corrosion, and erosion. Additionally, novel thermal management system will be designed, to optimize the heat quality of the waste heat and control the heat flux of the propulsion system. Optimal operation conditions will also be investigated. A simulation model will be set up for operation parameter optimization. First functional lab scale tests of exFan will serve to verify such model. The breakthrough innovations proposed in exFan will i) allow European aircraft producers to offer savings in cost operation ii) enable European aeronautics industry to maintain global competitiveness and leadership, and iii) create significant contribution in the path towards CO2 and NOX emission free aircrafts. exFan brings together multidisciplinary experts from academia, aeronautical associations and industry, supported by a selected technical advisory board. exFan will be in close contact with Clean Aviation and Clean Hydrogen to create synergies and speed up the development.