The development of electrically powered actuators (EPA) for flight controls is considered a major milestone in the progress of the "All Electric Aircraft". The objective of the project is to demonstrate the feasibility of producing an electrically powered primary flight control actuation system.
This project demonstrated the feasibility of producing electrically powered actuators (EPA) for primary flight control actuation. 2 different versions of each actuator concept have been evaluated. 2 slightly different linear electromechanical actuators (EMA) differentiated by the technology of their output screw:
and 2 slightly different electrohydrostatic actuators (EHA) differentiated by the technology of the hydraulic pump:
fixed displacement pump;
variable displacement pump.
Breadboards have been built for the 4 above versions, the EMA being more representative of a flightworthy unit than the EHA. The breadboards have been operating in their benches and have been submitted to preliminary testing. From the analysis of the data available it seems that the EMA approach has better efficiency and hence lower power consumption than the EHA solution. On the other hand it has more mechanical complexity and has the problem of the jamming of the actuator. Looking into the EHA solutions, the fixed pump version seems more adequate for small to medium actuator power levels while the variable pump version promises better efficiency for high power requirements. The analysis, simulation activities and breadboard preliminary testing completed during the project show that both actuator concepts EMA and EHA are able to meet the specification requirements.
The investigations (studies, specifications, predesign and testing), will cover all types of EPAs, namely EHAs (electrohydrostatic actuators), and EMAs (electromechanic actuators).
Where necessary, hardware demonstrators will be built to validate the concepts for primary flight control applications.
The actuators will have integrated intelligent, digital control and monitoring loops in order to interface with a preferred aircraft digital bus (electrical or optical).
A common specification issued by the team of aircraft manufacturers led by CASA will be developed by 2 teams of equipment manufacturers and universities. One, led by Lucas Air Equipment, will work on electromechanism actuators, while the other, led by Liebherr AT, will deal with electrohydrostatic actuators.
A comprehensive trade-off study between both technologies will be carried out by the aircraft manufacturers team and will be largely based on the following criteria:
Improving performance capability.
Failure behaviour, monitoring and isolation.
System efficiency (ie, power consumption).
The cooperation between aircraft and equipment manufacturers makes possible the future design of the most economic and suitable components for the next generation of civil European aircraft.
Funding SchemeCSC - Cost-sharing contracts
GU14 6YU Farnborough
1100 AE Amsterdam
88161 Lindenberg - Allgäu
WV10 7EH Wolverhampton