Skip to main content
European Commission logo print header

DEsign, development, manufacture, testing and Flight qualification of nExt geNeration fuel storage system with aDvanced intEgRated gauging and self-sealing capabilities

Periodic Reporting for period 4 - DEFENDER (DEsign, development, manufacture, testing and Flight qualification of nExt geNeration fuel storage system with aDvanced intEgRated gauging and self-sealing capabilities)

Reporting period: 2022-01-01 to 2022-12-31

The DEFENDER project aims at developing, manufacturing, testing, and qualifying innovative next-generation fuel storage system with innovative features to be integrated into the Next Generation Civil Tiltrotor (NextGenCTR) framed in the Fast Rotorcraft (FRC) Innovative Aircraft Demonstrator Platform (IADP). The first step consists of a specification review and preliminary system design activity and a technological study, both aimed to design the fuel system and assessing the effectiveness of the proposed innovations. The Fuel System architecture will be used to drive the next detail design phase. Starting from the requirements, the specification of the interfaces and the digital mock-up, the DEFENDER consortium will proceed with the design (at mechanical, electric discharge, electronic and hydraulic level) and analysis, by minimizing the weight and maximizing the safety. Special care will be dedicated to the advancement “beyond the state of art” even during the early stage of the design.
During the first period, the actions performed were related to the definition of the project requirements and the trade-off analyses between different innovative configurations. Such activities have been detailed in the documentation for the Preliminary Design Review. Besides the material selection for the tanks, analyses have been performed to assess innovative technologies, especially the application of the Additive Layer Manufacturing technique for the production of metallic interfaces and connections. The first results revealed that the ALM technique might be an effective procedure to optimize the metallic parts of the FSS.

The technical activities performed during the second reporting period concerned the definition of the most relevant technical aspects to achieve the go-ahead for the tooling and manufacturing phase.
Such activities mainly concerned the definition of material properties to calibrate the numerical simulations, the assessment of cost and environmental impacts of the Additive Layer Manufacturing (ALM) technique, the topological optimization and design of the ALM flanges, the definition of the engineering program plan for what concerns the defect qualification for the ALM flanges, and the drop tests definition. Moreover, other activities were devoted to defining all shape details of tanks, interfaces, and provisions. Advanced numerical simulations of the crash test have been performed by considering a representative fuel tank/wing assembly.

The technical activities performed during the third reporting period mainly concerned the manufacturing process of various components of the fuel storage system. The tools' production required for the whole system has been completed, and the first set of lightweight tanks has been prepared together with the related foam blocks. As far as the flanges made with the Additive Layer Manufacturing technique are concerned, permeability, vibration, and tomography tests have been performed on representative structures. Optimization activities have been then carried out to improve the components' quality, and the second set of flanges has been produced.
Moreover, the experimental cube drop test was performed at CIRA, supported by Aero Sekur's experts. The tests were carried out to verify the tear resistance requirement of the material of a tank demonstrator, i.e. leakages of fuel after an impact on a rigid platform are not allowed (European airworthiness standard CS-29.952). In addition, the experimental results have been correlated with high-fidelity numerical predictions.
Accurate simulations of the crash test have been performed by considering the most critical fuel tank/wing assembly. The failure modes and flexibility of bladders, distribution lines, and provisions have been considered in the models. The numerical results have been compared with experimental data obtained for a similar configuration for validation purposes.

During the fourth reporting period, all technical activities were completed. In particular, both sets of lightweight tanks and the related foam blocks and flanges made with the Additive Layer Manufacturing technique have been manufactured. Moreover, installation procedures and the components' dimensions have been verified to ensure compliance with the actual NextGenCTR volumes. Finally, the experimental-numerical correlation of the cube drop test and the test rig's design for the drop of the full-scale configuration have been finalized.
During the project, the Consortium reported the main scientific results in six peer-reviewed open-access papers and participated in six conferences/workshops. Moreover, the exploitable results expected at the beginning of the project have been achieved.
The potential impacts until the end of the project are:
- a weight reduction of the subsystem;
- reduction of the manufacturing and maintenance costs;
- reduction of the lead time with advanced manufacturing techniques;
- safety improvements.
Design of the test rig for the prototype drop test
Cube drop test
3D simulation of fluid-structure interactions
A fuel tnak of the first shipset
Vibration test of ALM flanges
Topological Optimization of possible components to be manufactured by ALM
Crash-test simulation results
Installation test
Numerical-experimental correlation for the cube drop test