The project named COSTAR “Compact innOvativeSmarT Actuators for next generation Rotorcraft” is part of the Fast RotorCraft (FRC) IADP program of Clean Sky 2 (CS2). COSTAR is a consortium composed by Protom Group SpA, based in Italy, and Triumph Group – Integrates Systems, located in Great Britain. The Project scope is to develop the actuation system of the primary and secondary flight controls targeting the final goal to demonstrate the reaching of TRL5 and then TRL6 for the technological solutions adopted to design the actuation system. The TRL5 and TRL6 demonstrations are based on ground and flight test campaigns performed on bench and then flyable models of the actuation system to be installed on a prototype of the FRC.


The primary flight controls actuators are employed to optimize the controls in roll, yaw, and pitch of the main rotor of the FRC. The secondary ones are used to control the movable surfaces of the wings, the horizontal and vertical stabilizers. The actuation system are controlled by the ’Autopilot Flight Control System to improve the rotorcraft manoeuvrability especially during the transition phases, between high and low speed, and to optimize the drag at high speed to reduce the fuel consumption improving the environmental respect.


The COSTAR consortium plans to design, manufacture, and qualify a new concept of modular actuation. The scope is to employ the same type of mechanical and electronic components, scaled according to the specific requirements, for all the actuations assuring the compliance to the safety and performance requirements.

The project is divided into four main phases.
The first one targets the capture of the design requirements and their assessment in order to define the actuation architecture. Different conceptual architectures have been developed to trade off the advantages and the disadvantages of each one to define which is the candidate that assure the major commonalities among all the actuations. That process allowed to define three different architectures: one for all the linear actuators, employed for the primary flight controls, one for the rotary actuators, employed for the secondary flight controls, and the third one for the control electronics of all the actuators.


The second phase has dedicated to the design, preliminary and detailed, of all the actuation and electronics components. During this phase the first preliminary engineering tests have been performed to verify the behaviour of the critical components. The scope is to reduce the risk associated to the compliance to the critical design requirements to avoid to make design changes during the testing phase. The engineering testing has also the objective to characterize the behaviour of the critical components evaluating the design data that cannot be captured by the supplier data sheets.
The third phase plans the manufacturing of the actuation prototypes e the executions of all the test required to achieve firstly the preliminary qualification required for the prototypes flight tests and then the achievement of the complete qualifications to perform flight tests without any restriction. During this phase different types of tests are planned: the integration tests to verify the proper integration of the designed actuation system with the rotorcraft interfaces, then the performance, the structural, and the fatigue tests. The target of this phase is the achievement of the TRL 5
The final phase is dedicated to the flight test campaign, to provide the necessary support to Airbus Helicopters to install the actuators on the prototype and to perfrom all the flight test campaign. The target of this phase is the achievements of the TRL 6 for all the actuation types.



The project ambition is to demonstrate the capability to actuate eight different control surfaces and the primary control command lines using two different types of actuators (three part numbers in total) and one type of control electronics. This latter one will implement control SW able to recognise which type of actuator has to be commanded, recognising its function according to the pin programming logic. This high level of commonality for so different types of actuation represents a challenging target of the project. The employment of similar components is subject to specific safety assessments as required by the SAE ARP4754a and by the SAE ARP4761.


The first achieved milestone was the Kick Off Meeting, arranged on December 15th, 2016 at the Airbus Helicopters premises of Donauworth (Germany). That meeting defines the formal starting of the conceptual design activities.
The second milestone was the Specification Review Meeting, arranged on March 2017 at the Airbus Helicopters premises of Marignane (France) having the scope to validate the preliminary requirements of the progest.
The third milestone was the Preliminary Design Review, arranged on March 2018 at the Triumph Integrated Systems premises located in Deeside (Great Britain), having the scope to present to Airbus Helicopters the preliminary design of flap actuators for the FRC secondary flight controls.


The next milestones are:
• Primary Flight control actuators PDR, that will take benefits from the analysis performed for the flap actuators as the kinematics actuators will employ the same type of components of the flap actuators, even if with some important specific components like the actuator screw and the relevant nut. The actuator electronics will be exactly the same of the flap actuators assuring the goal to achieve the maximum possible commonality between the actuators.
• The Critical Design Review (CDR) is planned for the beginning of the 2019. Its target is to freeze the design solutions to start the manufacturing phase
• The first prototype of the actuators to be available to perform the Avionic Integration Test and then to be installed on the first prototype of the rotorcraft. The target date is the beginning of 2020
• The preliminary qualification phase to get the pDDP necessary for the request of permit to fly to be completed for the beginning of 2020. Then COSTAR will proceed with the fatigue tests to get the complete qualification (DDP).
• The maiden flight is currently planned for the end of 2020

Scatola Elettronica Controllo Attuatori

Actuator Control Electronics


Secondary Flight Control System Architecture


Flight Control Surface Actuator

The COSTAR Consortium

The consortium is made by Protom Group SpA and Triumph Integrated System Ltd. Protom has the role of project coordinator and has the responsibility to perform the safety assessments. Triumph is in charge to design, manufacture, verify by test and qualify all the actuators with the related electronics box. The Consortium as whole is in charge to provide all the necessary support to Airbus Helicopters to integrate the actuators on the prototype, to get the prototype permit to fly, and to support the flight test campaign.
The consortium allows both Protom and Triumph to acquire new know how in the field of the modular electromechanical actuation development, increasing the capability to compete in the aeronautical market.




This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727122.