HELIOS

Motivation

Concepts for future developments in short- and medium-range aircraft must be lighter, suitable for high-rate production, and more cost-efficient than current models in order to meet market demands. Innovative fiber composite technologies – regarding new materials, manufacturing techniques, structural designs, and adapted design methodologies – can contribute significantly to potential weight savings. Complementary projects primarily investigate structural concepts based on technologies that are already considered fundamentally technically feasible and have been proven to function at laboratory scale.

In the joint project “HELIOS“, Fraunhofer IFAM and Fraunhofer IWS, together with nine other partners, pursue the goal of developing and validating novel design principles based on innovative manufacturing technologies, adapted design methodologies, and synergistically acting cross-cutting technologies, which currently exhibit a significantly lower level of technological maturity.

Aims and Procedure

HELIOS pursues the following scientific and technological objectives:

1. Within the scope of the project, weight savings of up to 1,610 kg are to be achieved for the defined project perimeter (typical fuselage section) compared to a current research benchmark. These savings aim to contribute to the reduction of CO₂-equivalent emissions.
2. In addition, high-rate capable and cost-efficient manufacturing processes will be developed, refined, and optimized to enable an economically viable production rate of more than 70 aircraft per month. The scalability and cost-efficiency of these processes will be assessed by extrapolating data from laboratory-scale demonstrations.
3. A further focus of the project is on increasing energy efficiency and reducing resource consumption in the manufacturing and assembly processes for CFRP fuselage structures. For example, production waste will be reduced by eliminating riveting processes (e.g., titanium collars, energy consumption, and tool wear associated with drilling and riveting). Moreover, the implementation of a high-rate capable surface inspection solution will eliminate the need for a complete inspection paint layer, along with its associated energy and material usage.Innovations and Perspectives

Fraunhofer IIFAM and Fraunhofer IWS are working on the development of inline pre-treatment and in-situ quality assurance methods for the cleaning/activation of CFRP surfaces, as well as an automated process chain for secure, high-rate capable, paste adhesive bonding of a thermoset CFRP fuselage longitudinal joint – from concept to a testable component – as an alternative to riveting.

To achieve this, IR emitters are spectrally modified using the DLIP (Direct Laser Interference Patterning) method to enable reproducible adhesive curing based on thermal convection. Additionally, an integrated tooling solution is being developed to allow temperature sensing and control, as well as the application of a defined contact pressure, precise bond line thickness adjustment, and control over the curing profile. Furthermore, feasibility studies are being conducted to assess the transferability of the process to fiber-reinforced plastics (FRP) with hybridized thermoplastic surfaces, enabling entirely new manufacturing routes for both existing and novel, disruptive aerospace components. Ultimately, a section of a real half-shell structure is to be joined in an automated process.

Innovations and Perspectives

The HELIOS project aims to achieve significant weight savings in short- and medium-range aircraft through innovative fiber composite technologies and new manufacturing methods. The development of high-rate capable production processes, along with the reduction of production waste and resource consumption, contributes not only to cost efficiency but also to the reduction of CO₂ emissions. Looking ahead, this approach opens up new possibilities for environmentally friendly aircraft components and, in particular, offers the potential to revolutionize manufacturing methods in the aerospace industry through the integration of innovative in-situ quality standards and automated adhesive bonding processes.