Actuation technology for flight control system on civil aircraft

This report addresses the author’s Group Design Project (GDP) and Individual Research Project (IRP). The IRP is discussed primarily herein, presenting the actuation technology for the Flight Control System (FCS) on civil aircraft. Actuation technology is one of the key technologies for next generation More Electric Aircraft (MEA) and All Electric Aircraft (AEA); it is also an important input for the preliminary design of the Flying Crane, the aircraft designed in the author’s GDP. Information regarding actuation technologies is investigated firstly. After initial comparison and engineering consideration, Electrohydrostatic Actuation (EHA) and variable area actuation are selected for further research. The tail unit of the Flying Crane is selected as the case study flight control surfaces and is analysed for the requirements. Based on these requirements, an EHA system and a variable area actuation system powered by localised hydraulic systems are designed and sized in terms of power, mass and Thermal Management System (TMS), and thereafter the reliability of each system is estimated and the safety is analysed. These two systems are then compared in fuel penalty, safety, maintenance and installation, cost, risk and certification. A conventional Fly-By-Wire (FBW) actuation system is used as the reference case. The results show that both the EHA system and the variable area actuation system are feasible for the FCS on civil aircraft. The EHA system is proved to be quite efficient in power consumption and mass reduction. However, the reliability of EHA needs to be improved and the TMS of this system may lead to an increase in aircraft drag. The variable area actuation system demonstrates that it can significantly reduce the system design point and system size; while the localised hydraulic system is not as efficient as a centralised hydraulic system. Finally, a variable area actuation system powered by the centralised hydraulic systems is suggested for the FCS on civil aircraft and the Flying Crane. A variable area actuation system powered by localised hydraulic systems is recommended as the first step towards MEA and AEA in the future.