NTN-SNR is a major supplier for the propellers blade bearing. That is why NTN-SNR answered to this topic of call 12. The global strategy of the project was divided into 4 major tasks which constitute the work packages of the project (WP2 to WP5) and one work package is dedicated to the management (WP1). This project was led according to NTN-SNR usual development process for new products or R&D projects.
The goal of NTN-SNR proposal was to meet the topic manager requirements. The Propellers Blades bearings were designed, manufactured and tested (component tests are required necessary to demonstrate the behaviour with different loads cases – TRL 5 is required ) to withstand the radial load of the propeller blade load in operating condition due centrifugal forces and unbalance loads, to withstand axial and tangential loads due to aerodynamic forces on the blade and to withstand to the high temperatures.
The global coordination of the project was the responsibility of the aerospace R&D project leader. The aerospace R&D project leader was the focal point for the topic manager. He was responsible for the time schedule and for the success of the project.
The bearing designs were performed by NTN-SNR Aerospace design office using its knowledge and its experience on this type of application and so innovative solutions will be implemented in these bearings.
The bearings were manufactured according to the NTN-SNR quality process, the certified standard process and the flight test safety requirements. The industrial validation report was delivered with the bearings.
To reduce the risks linked to the chosen concepts, several specific tests were performed by the NTN-SNR test centre and by the material laboratory and by specialised vibratory.
NTN-SNR had the knowledge and the experience in design, manufacturing, testing, in certification of aircraft engine bearings and in test bench design and modification.
The SNRPBBearing project, led by NTN-SNR, was a SAGE 2 Integrated Technology Demonstrator from the Clean Sky programme. The goal of this project was to design, manufacture and test the propeller blade bearings for the upstream and downstream propellers of SAGE 2 Open Rotor.
The Upstream Propeller module consists of 12 propeller blades and the Downstream Propeller module consists of 10 propeller blades. The propeller blades of the two rotors are attached to polygonal rings and are orientated at various angles by the two independent Pitch Control Mechanisms.
The propeller blade bearings ensure the transfer of aerodynamic and centrifugal loads to the respective polygonal rings while allowing the pitch change of the blades.
The main functions of these bearings are to:
- allow oscillatory rotation between the polygonal ring and the propeller blade shaft;
- transmit the centrifugal and aerodynamic loads from the propeller blade to the polygonal ring;
- be resistant to the environment;
- ensure the stiffness between the propeller blade root and the polygonal ring;
- resist the load caused by the loss of a propeller blade (twice the maximum centrifugal load).
The objectives of the project were to:
- design the two bearings for each propeller;
- define the mitigation plan to reach TRL5;
- complete the mitigation plan and especially the development tests;
- successfully pass the validation test;
- manufacture the bearings for the two propellers;
- deliver 26 bearings to the Topic Manager.
At the end of the project, all the objectives had been achieved. All the tests were performed successfully, and the bearings were delivered to the Topic Manager.