Overview
Rapidly emerging hydrogen and fuel-cell power-based technologies can now be exploited to initiate a new era of propulsion systems for light aircraft and small commuter aircraft. In addition, these technologies can also be developed for the future replacement of onboard electrical systems in larger 'more-electric' or 'all-electric' aircraft.
The feasibility of this project depends on several key-enabling technologies including fuel-cell stacks and integrated systems, hydrogen fuel storage and a safe airport-based hydrogen-refueling infrastructure. Another important consideration is that it should demonstrate the path to future economic viability.
The primary advantages of deploying these technologies are low noise and low emissions - features which are particularly important for commuter airplanes that usually takeoff and land from urban areas. The possibility to takeoff and land within the noise abatement regulations set for small airfields, in urban areas and near population centres, will allow the use of these airfields late at night when noise abatement regulations are even more stringent.
The main objective of the ENFICA-FC project was to develop and validate the use of a fuel-cell-based power system for propulsion of more-/all-electric aircraft. The fuel-cell system was installed in a selected aircraft which would be flight and performance tested as proof of functionality and future applicability for intercity aircraft. It would also demonstrate that noise levels and pollutant emissions could be significantly reduced, or even eliminated, by more-/all-electric aircraft in the air and on the ground.
All the main objectives that were dealt with the ENFICA-FC project respond to the major challenges identified in the Strategic Research Agenda for European aeronautics:
- Research for strengthening the competitiveness of the aeronautical industry in the global market, responding to the challenge of delivering more economical, high performance and better quality products and services.
- Research for improving the environmental impact with regard to emissions and noise, responding to the challenge of meeting the society’s demand for sustainable transport.
The project offers opportunities for new operational concepts resulting in the following:
- Noise abatement friendly
- Low or zero pollutants
- Takeoff and landing from short airfields under 2000 feet.
The following work was implemented within the project:
- The feasibility study included:
- identification of requirements of specific applications for regional transport aircraft (APU, primary electrical generation supply, emergency electrical power supply, landing gear, etc.);
- preliminary definition of propulsion system including: fuel stack (comparison between PEM, SOFC, MCFC, etc.), hydrogen storage or direct onboard production, fuel-cell system, electric motor and power management system;
- definition of preliminary relevant systems and subsystems; integration of fuel-cell systems in the pressurised structure of aircraft operational behaviour;
- safety, certification, maintenance and installation
- reliability and maintainability concept definition; life-cycle cost evaluation.
- feasibility study of an all-electric propulsion inter-city aircraft (10-15 seat), completely powered by fuel cells, in order to assess the impact that could have a more silent and less polluting aircraft.
- a scale-size, electric motor-driven airplane powered by fuel cells has been developed and validated by a flight test.
- An existing, highly efficient design of a two-seater aircraft that has already been certified has been used. The fuel-cell system and the electric motor has been integrated onboard; the flight control system has been also converted into an electric system. The following items have been pursued:
- a fuel-cell unit was designed, built and tested in a laboratory ready to be installed onboard for flying;
- highly efficient brushless electric motors and power electronics apparatus were designed and manufactured ready to be installed onboard for flying;
- an efficiency of about 90% was obtained by an optimised aerodynamic propeller design;
- a study of the flight mechanics of the new aircraft was carried out to verify the new flight performance;
- a flight test bed of the aircraft, capable of remaining aloft for one hour, was the main goal of the project to validate the overall high performance of an all-electric aircraft system.
Funding
Results
The ENFICA-FC project, which began 2006, finished positively with the final test flights in the months of May 2010; for this reason, the Politecnico di Torino research group, headed by Professor Romeo (Engineers Fabio Borello, Gabriel Correa, Enrico Cestino and Marco Pacino), has been offered hospitality at the Reggio Emilio airport.
The starting up, functioning under power and taxiing tests of the aircraft with its definitive propeller were carried out along the 1 400 meter runway at the Reggio Emilio airport. The first high speed taxiing tests (120 km/h) were successfully carried out on the Rapid 200-FC 'zero emission' aircraft between December 2009 and February 2010.
The hydrogen as high pressure (350 bar) (supplied by Air Product), the 20 kW LiPo battery set and the electric engine have proved to be reliable and offer continuity of supply of the more than 40 kW power necessary for takeoff. The sophisticated electronic control system ensures redundancy and makes both sources of energy available to the pilot in order to guarantee the safe functioning of the single propeller, even in the case of breakdown of the hydrogen current generators.
The airplane (whose final lay-out was achieved with the technical assistance of the Italian Skyleader importer – T&T Ultralight) has a wing span of about 10 meters and total weight of 550 kg (850 kg was the total weight of the Boeing project). With the systems at present available, the airplane has autonomy of about 1 hour and can reach a cruising speed of 150-160 km/h, thanks to the hydrogen alone.
A new speed world record of 135 km/h and an endurance of 39 min. were established during several flights conducted for the FAI Sporting Code Category C (airplane). 2.5 hours of effective flight were obtained during these 6 tests for a total path of 237 km. The first flight of fuel cell powered airplane at a cruising speed of 100 km/h for approximately 25 minutes was held, in absolute, by Boeing but with a motor-glider (FAI Cat D).
Among the advantages of an aircraft of this type, mention can be made of its remarkable silence: a characteristic that can greatly improve the quality of live around city airports.
At the same time, more theoretical type studies have been carried out (in collaboration by the Israel Aerospace Industry, Université Libre de Bruxelles and Evektor (CZ) partners). These will not have an immediate practical application in the initial stages because of the present technological limits, but have t
Innovation aspects
Project Main innovative aspects:
- First European and World flight test of an airplane powered by fuel cells;
- First European feasibility and reliability study of high efficiency fuel cells energy propulsion system & brushless electric motors for transport aircraft.
- Development of Fuel Cells technology and its application in aviation leading to enhancements in the European industry.
- Low noise and low emissions aircraft. In the case of using pure Hydrogen fuel, the result is zero emissions. The low noise and low emissions advantages are particularly important for small transport airplanes that usually takeoff and land from urban areas.
- The more-/all- electric aircraft has advantages in reliability, maintainability and in some aspects of the performance- only slight reduction in engine performance due to altitude.
- No other project funded by the European Commission has such ambitious results and it was presented on ground and in flight in a public event within the scheduled time.
- The positive handling qualities and satisfactory engine performances of these six flight tests have led the team to consider these successful flights as a good starting point for further long endurance high speed flights.