|Hybrid/Electric Aircraft Design and STAndards , Research and Technology (HEADSTART)|
|Applied Vehicle Technology|
aeropropulsion, aircraft design, annexed technologies, architectures, costs, distributed propulsion, hybridelectric, military, power, signature, systems
The term “hybrid-electric” refers to the adoption of integrated systems based upon advanced electrical machines, power electronics and secondary energy storage. There exist two main categories when it concerns hybridized systems solutions: (1) Non-propulsive including environmental control, flight control, landing gear, ice protection, as well as functions catering for ground manoeuvring and providing emergency power; (2) Propulsive which could allow for enhanced overall propulsion system efficiency. A good measure of activity has been taking place when it concerns civilian application of hybrid/electric propulsion and power systems, e.g. VTOL and fixed-wing aircraft for passenger transportation and for utility drones. In 2017, a dedicated Exploratory Team AVT-ET-173 Hybrid/Electric Propulsion for Airborne Vehicles (HyPAV) is examining the question as to whether this particular subject warrants further attention in the future.
The primary aim of this activity is to establish a team of technical specialists dealing with hybrid/electric propulsion systems, and, based on their expertise a technical report detailing a research and development roadmap leading to a flying testbed/demonstrator programme is envisioned. Initially, brainstorming will take place in order to create a concept cloud of future use cases, which will then be tested for feasibility as the RTG work progresses. Through mutual consensus the RTG will declare taxonometric conventions, standardised schematic symbols of components/sub-systems, architectural parametric descriptors and figures-of-merit, analysis methods according to pre-determined fidelity levels, and, formalised procedures for inter/multi-disciplinary interfacing and optimisation. Based upon the insights and ensuing discussions generated by the RTG from published observations/conclusions drawn from in-house investigations conducted by industry together with academic and dedicated research institutions a series of chronologically assigned specific quantities and performance targets will be declared for components/sub-systems relevant to hybrid/electric propulsion. To round off, in an effort to address future operational requirements, regulatory considerations and certification different integrated vehicle design(s) servicing specific mission roles, e.g. MALE/HALE/UCAV (or others), will be reviewed.
The following technical areas will be scrutinized in detail:
Hybrid-Electric Propulsors – involves examination of candidates that incorporate thermal engines coupled with an electric motor that is driven by a secondary electrical energy source. Parallel and series-parallel configurations that incorporate mechanical power-train coupling to the low-pressure as well as high-pressure spools could result in hybrid-compressors, propulsors and hybrid-turbo-machines.
Electrical Energy Storage, Power Management and Distribution – the performance, flexibility, safety and redundancy of parallel and series combinations of energy storage media (batteries or capacitors or fuel cells) is to be examined. Also, high voltage, DC and super-conducting electrical network options shall be explored Includes considerations related to thermal regulation and control.
Electrical Machines and Power Electronics – technologies providing minimum size and weight electrical machines and power electronics conversion whilst maintaining high conversion efficiency should be examined. This topic also includes any considerations related to thermal regulation and control.
Synergistic Annexed Technologies – ideas related to annexed technologies like distributed propulsion, which may serve to further enhance overall performance by generating significant synergy effects with hybrid-electric motive power systems. This also includes fully or partially embedded propulsion within the airframe to exploit benefits from Boundary Layer Ingestion and Wake Filling. Another topic under this category could be autonomy in relation to the complex interaction, in real-time, of expert systems onboard the aircraft, e.g. electrically actuated adaptive structures.
All will be examined in terms of technology type, performance and specific quantities according to service entry chronological waypoints of year-2020 (state-of-the-art at TRL6), year-2035 and year-2050.