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FP7

DEAMAK Report Summary

Project ID: 271496
Funded under: FP7-JTI
Country: Belgium

Final Report Summary - DEAMAK (Design And Manufacture of Krueger Flaps)

Executive Summary:
Natural laminar flow (NLF) wings are among the key technologies being developed to reach ambitious reduction goals wrt fuel consumption and emissions proposed in the Vision 2020 of the Advisory Council for Aviation Research and Innovation in Europe (ACARE). Krueger flaps are leading edge high-lift devices needed to increase the critical angle of attach at low speed flight phases and hence delay the onset of stall (sudden loss of lift force). They are particularly well suited for NLF wings since they deploy from the lower part of the wing, leaving the upper part smooth to facilitate NLF, as opposed to traditional slats used on most aircraft today. Furthermore, in extended setting, they protect the fixed leading edge of the wing against insect and debris impacts that could have a detrimental effect on the laminar wing characteristics in cruise phase afterwards, namely a preliminary transition of the boundary layer on the upper side of the wing from laminar to turbulent flow resulting in increased friction drag and hence jeopardizing the benefits of the NLF profile.

The Clean Sky Joint Undertaking-funded project 'DEsign And MAnufacture of Krueger flaps' (CfP DEAMAK) relies on the expertise of the project leader ASCO Industries - a family owned multinational headquarted in Zaventem, Belgium - in the development of high-lift device movables for all recent major commercial civil aircraft programs above 100 seats. Following the 6 year project DEAMAK within the Clean Sky Smart Fixed Wing Aircraft Integrated Technology Demonstrator (CS SFWA ITD) research program, ASCO engineers will be able to deliver the Krueger flaps mid-2017 for use on the Breakthrough Laminar Aircraft Demonstrator in Europe (BLADE). Practically, the outer wing sections of the Airbus A340-300 MSN1 will be replaced by new NLF wing ones and several flight tests will be organized within BLADE. At the end of the BLADE flight test campaign in 2018, 23 flight hours with Krueger flaps are foreseen to assess their so-called insect-shielding properties.

After a feasibility study including analysis of available space, stress, bird strike resistance, manufacturability and cost, ASCO researchers selected carbon fibre-reinforced plastic (CFRP) as material for the Krueger panels and developed a multi-cell concept. Following a detailed design phase during which ASCO conducted non-linear finite element bird strike analyses of the Krueger flap CFRP panel and metallic wing attachment structure, they have investigated manufacturing of the novel CFRP flaps via resin transfer moulding, including both experimental trials (coupon testing and production of sub-elements) and theoretical analyses enabling a design freeze of the structure.
In parallel a series of validation tests (from coupon level till reduced size risk reduction article production and testing) were carried out, enabling to give green light for the design and production of specific moulds for the full-scale parts.

During the last 2 years of the DEAMAK project, three Krueger Flaps prototypes were built at ASCO (mainly for RTM mould validation and US-NDT calibration purposes), all production process parameters (dry carbon fibre satin weave preforming parameters, RTM6 resin injection rates, curing times and pressures, etc.) were frozen and the flying shipset for BLADE was produced successfully. In parallel, all special processes like the preforming, resin transfer moulding, painting, drilling, blind bolt installation, visual and US-NDT inspections needed for the production, assembly and control of the DEAMAK structure on ASCO site were qualified by Airbus in the frame of BLADE, proving the ASCO team had invested sufficiently and had acquired the required knowledge to be able to produce airworthy composite parts.

Finally, the different Airbus design maturity gates were passed successfully and all required Permit to Fly inputs were prepared all along the DEAMAK project. The latter ranges from for instance stress notes and approved V&V matrices during the Engineering phase to several production related deliverables like FAI reports of all components shipped to the FAL and a FPQ QTR of the critical component (summarizing all successful assessments and testing done on the CFRP Krueger panel).

Project Context and Objectives:
The purpose of the DEAMAK project was for ASCO to design and manufacture Krueger flap leading edge high-lift devices for insect-shielding assessments during the last batch of BLADE aircraft flight tests within CS SFWA ITD. Krueger Flaps are particularly well suited for NLF wing applications since they deploy from the lower part of the wing, leaving the upper part smooth to facilitate NLF, as opposed to traditional slats used on most aircraft today. Furthermore, in extended setting, they protect the fixed leading edge of the wing against insect and debris impacts that could have a detrimental effect on the laminar wing characteristics in cruise phase afterwards, namely a preliminary transition of the boundary layer on the upper side of the wing from laminar to turbulent flow resulting in increased friction drag and hence jeopardizing the benefits of the NLF profile. Especially the latter is to be investigated in the frame of BLADE NLF flight test campaign.

Expected hardware at the end of the DEAMAK project were 2 Krueger panels (1 per wing) as well as the required specific wing attachment structures to feed the BLADE NLF research program. Since airworthy components need to be delivered, all the corresponding paperwork needed to be prepared. This ranges from design maturity gate passing evidences, complete 3D models, 2D drawing sets, detailed stress notes, approved V&V matrices, FAI reports of all components shipped to the FAL, an FPQ QTR summarizing all successful assessments and testing done on the critical components to special process audits (drilling, painting, inspections, etc.).

Project Results:
The main Scientific and Technical results and foreground of DEAMAK for ASCO are the complete development and validation of an airworthy CFRP multi-cell Krueger flap structure produced in house by means of a one shot RTM out of autoclave process.

First of all the different design maturity gates of Airbus were passed following the preparation of all required technical inputs ranging from design data to stress models and reports. Especially non-linear finite element analysis capacities were drastically increased at ASCO during the DEAMAK project thanks to in-house developments and collaboration with Airbus experts. This enabled to validate the stringent bird strike requirement for the Krueger flaps, their most important design driver in practice.

Secondly, all the skills needed to correctly preform weaves of dry carbon fibres in an industrial environment and to correctly inject and cure airworthy composite parts by means of RTM were further developed within and positively audited by Airbus in the frame of DEAMAK. Several special audits were passed with success proving sufficient tools, training and knowledge was acquired at ASCO for specific manufacturing, assembly and control tasks. The latter forms an important asset for ASCO which is now able to participate to commercial bids for hybrid (metal/composite) of for full composite structures while the company historically only obtained contracts for full metallic components before DEAMAK. ASCO’s commercial and strategic competitiveness on short- and mid-term was thus clearly increased thanks to participation in the DEAMAK/BLADE program partly funded by the Clean Sky Joint Undertaking.

Finally, thanks to its professionalism and excellent team spirit, the ASCO team active on DEAMAK acquired a broad recognition resulting in a.o. the nomination of the DEAMAK project for the Best Clean Sky Project award in 2015 [1] and the chance to present a roll-up banner during the first edition of the Clean Sky Forum in 2015 [2]. Furthermore, several proposals for involvement in similar EU-funded projects could also be obtained thanks to the appreciated work done by ASCO in the frame of DEAMAK, which also helps to strengthen the technical advantage of ASCO on mid- and long-term.

Potential Impact:
Preliminary weight and cost assessment compared to full metallic variants of the Krueger flaps reveal significant advantages of the integrated composite structure developed by ASCO in the frame of DEAMAK. However, it is impossible at this stage to quantify the effect on C02 and NOx emissions and hence to assess how much the output of the DEAMAK project contributes to the ACARE 2020 objectives. It is however judged that the Krueger Flap is an indispensable mean to allow industrialisation of a laminar wing, offering a 4,6% fuel burn and hence CO2 reduction compared to conventional wings on a 800 NM mission at Mach 0.75 (includes weight increase and laminarity only above FL220) according to the Airbus BLADE project manager in July 2015.

In terms of exploitation of DEAMAK results, additional improvements are identified, especially wrt the preforming operations carried out manually in an Airbus qualified composite prototyping shop at ASCO for the BLADE prototypes. These could be automated and hence speed up in future commercial applications in an industrial environment (tailor made production line at ASCO). Obtaining new contracts will enable the ASCO Group to at least sustain its current position in the worldwide aeronautics and hence secure the ca. 1500 jobs within the group.

Participating to BLADE through the DEAMAK CfP was of paramount importance for ASCO since it was the first time that airworthy composite components were produced within the ASCO Group. Therefore, several articles were published during the DEAMAK project duration, not only internally [3][6] on the ASCO Intranet, but most importantly in leading Belgian [4][5], European [7][8] and global [9] magazines. On top of that, two displays of hardware at leading aeronautical fairs were made (DEAMAK prototype on ASCO booth at Le Bourget 15-18/06/2015 [10] and at Farnborough 18-21/07/2016 [11]). Finally, the details of the engineering work done during the design and production phase of the DEAMAK project were also presented by ASCO at SAMPE EUROPE 2016 in Liège, Belgium mid-September 2016 [12]. A DEAMAK Krueger flap prototype was on display on the ASCO booth as well during that conference [13]. All these initiatives enabled to officially position ASCO on the worldwide market as the partner of choice for hybrid or full composite aircraft safety-critical components, next to the metallic structures capability already present in the past.

List of Websites:
www.asco.be
Michaël Raets, Technical Project Manager, ASCO Engineering, michael.raets@asco.be
Stein Janssens, Group Leader Research & Innovation and Test & Development, ASCO Engineering, stein.janssens@asco.be

Related information

Contact

Stein Janssens, (R&D Section Leader)
Tel.: +32 2 7001436
Fax: +32 2 7168997
E-mail
Record Number: 195947 / Last updated on: 2017-03-10
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