Overview
Nowadays lightweight structures are mandatory in order to significantly reduce CO2 emissions of any aircraft. Unfortunately, production costs of low weight structures are more expensive than those of classical structures.
The tail cone has a very special position relating to aircraft systems, being both a component of the aircraft fuselage (ATA54) and also an interface of the Auxiliary Power System (ATA49). Today's tail cones are made of composite materials and are heavy. This is mainly because of the large number of requirements introduced by equipment integration. They are also costly, due primarily to the manufacturing costs of the double curvature stiffened structure (this is partly due to assembly constraints and partly to lay up constraints).
The ADVITAC (Advanced Integrated Tail Cone) project dealt with the development and production of aircraft composite structures. The ADVITAC consortium addressed the key issues concerning the composite tail cone structure and subsequent APU integration.
The consortium addressed a set of solutions regarding the following High Level Target Concepts: the cost efficiency air transport system HLTC and the ultra green air transport system HLTC. The ADVITAC project aimed at:
- Lowering production costs by 30% with regards to the actual composite aero structure;
- Lowering weight by 10% with regards to the actual composite aero structure;
- Specifying a new generation of composite architecture, allowing an extensive function integration (acoustic, fireproof, electrical and strength);
- Significantly improving the knowledge of interaction between innovative technologies, allowing a fully automated integrated process, including automated dry perform, through thickness reinforcement and an infusion process.
The State-of-the-Art technologies in the ADVITAC project addressed key project goals associated with lowered costs and lowered weight. This included automated processes, less fully integrated structures, enhanced composite properties and new structures and architecture.
The ADVITAC consortium provided an overview of all the set of problems concerning tail cone structure and APU integration. Significant weight and cost savings were expected after all partner issues had been consolidated in a design to cost approach.
The ADVITAC project was coordinated by Daher Aerospace (France), along with partners Coriolis Composites (France), Inasmet-Tecnalia (Spain), FFT (Belgium), NLR (The Netherlands), Recomet (Romania) and Cranfield University (UK). Embraer (Brazil) and Honeywell (USA) were involved as observers.
Funding
Results
A fully integrated tail cone composite structure has been designed, including:
- Full CAD structure + integration;
- Calculation dossier;
- Main functions validated on coupons;
- Engine noise simulation + acoustical solutions benchmark.
A full scale demonstrator of the tail cone structure has been manufactured including:
- A technological maturity readiness increase through small scale demonstrators.
Major maturity readiness increase has been achieved on the dry fiber placement technology:
- DFP/infusion material allowables, thanks to characterisation performed on coupons;
- Process maturity increase thanks to small scale demonstrators (validation before tail cone manufacturing);
- Interaction rules optimisation between DFP and design.
Major maturity readiness increase has been achieved on the reinforcement technology: tufting of stiffeners for the demonstrators.
Major maturity readiness increase has been achieved on low cost composite infusion tools.
Scientific progress has been achieved with new technologies, such as:
- Infusion of resin doped with nanotubes or graphen;
- Use of nanotube buckypaper to fight against fire and lightning strikes;
- Use of Bragg fiber technology to monitor infusion and loads in the manufactured structure.
Innovation aspects
Significant progress in the knowledge of design and manufacturing of large composite structures using the process of dry fiber placement + infusion.
Strategy targets
Innovating for the future: technology and behaviour.
Promoting more sustainable development.
Readiness
Some technologies are now ready to be used for industrial application, such as:
- Dry fiber placement mean;
- Acoustic simulation tools;
- Composite molding tools
Other technologies have gained in maturity and will be benchmarked for future industrial project, such as:
- Composite tail cone structure design
Although some progress has been achieved, some technologies stayed at laboratory maturity level, such as:
- Assembly and reinforcement through the thickness by tufting;
- Monitoring with Bragg fiber;
- Nanotube buckypaper;
- Epoxy resin doped with graphen or nanotubes.