Final Report Summary - AFLONEXT ("2nd Generation Active Wing“ – Active Flow- Loads & Noise control on next generation wing)
Executive Summary:
AFLoNext is a four-year EC L2 project with the objective of proving and maturing highly promising flow control technologies for novel aircraft configurations to achieve a quantum leap in improving aircraft’s performance and thus reducing the environmental footprint. The project consortium is composed of forty European partners from fifteen countries. The work has been broken down into seven work packages. The AFLoNext concept is based on six Technology Streams which cluster the targeted technologies and their associated contributions to advanced aircraft performance as follows:
(1) Hybrid Laminar Flow Control (HLFC) technology applied on fin and wing for friction drag reduction and thus performance increase in cruise conditions.
(2) Flow control technologies to enable more aggressive outer wing design for novel aircraft configurations, thereby improving the performance and the loads situation in low and high speed conditions.
(3) Technologies for local flow separation control applied in wing/pylon junction to improve the performance and loads situation mainly in take-off and landing conditions.
(4) Technologies to control the flow conditions on wing trailing edges thereby improving the performance and loads situation in the whole operational domain.
(5) Technologies to mitigate airframe noise during landing generated on flap and undercarriage and through mutual interaction of both.
(6) Technologies to mitigate/control vibrations in the undercarriage area which are caused by highly unsteady or inhomogeneous inflow conditions in take-off and landing conditions.
AFLoNext aims to prove the engineering feasibility of the HLFC technology for drag reduction on fin in flight test and on wing by means of large scale testing. The project shows also engineering feasibility for vibrations mitigation technologies for reduced aircraft weight and noise mitigation technologies.
The peculiarity of the AFLoNext proposal in terms of holistic technical approach and efficient use of resources becomes obvious through the joint use of a flight test aircraft as common test platform for the above mentioned technologies.
To improve aircraft performance along the whole flight regime, locally applied active flow control technologies on wing and wing/pylon junction are qualified in wind tunnels or by means of lab-type demonstrators.
Project Context and Objectives:
WP1 - Hybrid laminar flow control (HLFC)
WP1.1 - Simplified HLFC-Operation Demonstration
The HLFC leading-edge was successfully manufactured by Airbus. Airtightness test and function test were performed and passed at DLR.
During the A2 F/T performed end of November 2017 unexpected vibrations of the HTP occurred which led to required modification on the HTP camera fairings. Since DLR received new Flight Conditions from EASA too late no second flight to validate the functionality of vibration mitigation could be conducted in 2017. A refurbishment phase was done in the following to prepare the A/C for another FT campaign.
The second working party to install the HLFC system and all FTI started in March 2018. Due to the successful validation of the modification of the HTP camera fairings in April 2018, the AFLoNext FT campaign could be started afterwards.
During five flights and 24 flight hours in total the design, manufactured and installed HLFC system could be extensively tested. Some flight tests were combined with WP3. Finally, the flight test was completed in Mai 2018.
The HLFC leading-edge performed well within the complete HLFC-operating envelope. Both active but also passive suction systems provided sufficient under pressure for every test point within the envelope. All FTI-systems worked stable and smooth during the complete flight test campaign.
The second refurbishment of the A/C was done during summer break.
DLR gathered all flight test data and compiled a delivery to the authorised partners. A preliminary data analysis was conducted showing good results and go do agreement with numerical predictions.
WP1.2 - Simplified HLFC Wing Concept Integration
AGI UK updated their laminar transition calculations to consider the measured pressure loss data of the manufactured suction skin that had higher porosity than expected. Corresponding modifications would lead to 50% fewer suction holes than originally assumed which would reduce the manufacturing cost of a second generation demonstrator. AGI UK also used advanced transition prediction methods to investigate the possible impact on transition of the surface distortions predicted from SONACA's finite element model. This predicted surface waviness was found to have only a small impact on the predicted transition location.
ONERA reviewed whether the updated suction distributions would alter the defined surface tolerance requirements. These tolerance requirements were found to be the same as originally predicted.
Overall aircraft assessment of aircraft with HLFC wings based on the AFLoNext WP1.2 concept was done by Airbus. The results showed the technology will be commercially viable if more work is done to reduce manufacturing costs and to reduce the system weight.
After manufacturing the suction skin for the Ground Based Demonstrator, SONACA updated their processes and manufactured higher quality skin panels using the Super Plastic Forming/Diffusion Bonding technique. This second phase of manufacturing showed that very good improvement regarding the the small distortions in the surface of the original skin panel.
Effectiveness of the three alternative structural concepts were reviewed by Airbus with recommendations made for future developments to help them reach TRL6.
Components for the Ground Based Demonstrator manufactured or purchased by ASCO, INVENT, DLR, INCAS, SONACA, TAI and Airbus then delivered to INCAS for assembly. Assembly of Demonstrator went to plan. Deployment of installed Krueger flap tested. The quality of the air system assembly was established using air pressure tests.
New deliverable on hail strike tests and simulation were completed by PW and VZLU. Results showed consistency between predictions of damage initialisation and propagation and test measurements.
The Ground Based Demonstrator was delivered to CIRA, installed in icing wind tunnel test and tested over a range of conditions. Effectiveness of hot air anti-icing system was established.
WP2 - Active flow control on airframe
The major objectives to be achieved in the last period of the project were closely linked to finalize the experimental parts and assess the results of the work package, which are:
− Perform the ¾ scaled wind tunnel test of the engine wing installation situation at the large wind tunnel facility T-101 at TsAGI to support a TRL 4 level demonstration of active flow control in this area of the wing;
− finalize and assess the harsh environment testing of the active flow control actuators at the facilities of INCAS to support a TRL 3 level demonstration on subsystem level
− establish a common comparison of numerical studies made by computational Fluid Dynamics (CFD);
− perform an assessment on aircraft level of the investigated technologies on aircraft level.
− The large wind tunnel test at TsAGI was successfully performed in September 2017 and verified the expected improvement of the flow by fully suppressing flow
separation past the engine-wing junction by application of Pulsed Jet Actuation
(PJA). The application of Synthetic Jet Actuation (SJA) suffered a failure of
the systems in operation that was verified by comparing pre- and post-test
isolated actuator performance measurements. The cause of the failure hasn’t been fully detected and needs further investigations and research in future
projects.
The harsh environment testing was successfully concluded at INCAS in August 2017. Ten different environmental conditions have been investigated, including extreme temperatures, rain, ice, sand & dust, and solid element contamination. In summary, both types of actuators, PJA and SJA,survived all tests aside the sand & dust, which turned out to be the hardest condition for both types of flow control actuators.
In order to assess the viability of CFD methods to predict and design active flow control technologies, a proper comparison of the results of the numerical studies has been performed as well as the transposition on the full aircraft. The comparison of the different CFD based design studies clearly identify preferred ways of application of active flow control for the two-investigated local flow control situations.
On aircraft level, an assessment has been made for the two concerned classes of aircraft, large transport aircraft and business jet aircraft. Both assessments conclude that the active flow control technologies investigated in AFLoNext are able to achieve the required performance requirements within the given limits of air and/or energy supply. As far as the investigations support the conclusion on TRL levels, the industrial assessment on aircraft level confirm a corresponding increase of maturity of Active Flow Control (AFC) technology within the AFLoNext project.
WP3 - Control means for vibration and aeroelastic coupling
Two NLG doors were manufactured and tested on A320 DLR ATRA A/C. Due to aero-elastic loads non-compliance, the affect was that no flight approval was granted. The
NLG door qualification could not be achieved. Hence, NLG door did not fly within AFLoNext WP3 flight test campaign.
Successful integrated F/T planning with WP1 have been done. The WP3 FTI was working as expected and the Permit to fly could be achieved.
Flight test data has been successfully gathered for NLG sandwich door (gathered for further qualification activities) and MLG door without and with devices. The achievement was a solid F/T database for prediction tools validation and device selection.
Furthermore, the flight test was successfully post-processed and analyzed.
The validation of computational analysis tools has also been summarized and reported.
Based on the F/T data and computational analyses, the identification on vibration control methods has been carried out and reported: tuned-mass-damper, deflectors, VGs and Spoiler.
WP4 - Noise control on airframe
WP4.1: Preparation of A320 flight test was done.
All parts were mounted at DLR's ATRA aircraft. Respective substantiation reports were issued by SAFRAN LS and DLR and finally handed over to EASA. Check at EASA is ongoing, up to now no-show stoppers identified.
WP 4.2.1: A320 flap system with porous flap side edge was re-installed at ATRA aircraft. Necessary repair work was conducted by Airbus prior to a/c installation. The flap is ready for flight, paperwork has been compiled by DLR and handed over to EASA.
Flight test general:
Preparations at DLR ongoing, permit to fly was issued at 27.08.2018. Noise flight tests were conducted at Cochstedt Airport. On basis of online evaluated overall sound pressure level data first checks on data quality and validity can be done on site. Offline analysed and corrected overall SPL data and spectral representations of all results will be provided in dedicated reports.
WP5 - Multifunctional trailing edge concepts
The technical activities were formally closed at a technical workshop, hosted by NLR Amsterdam in May 2017. This newsletter contribution summarises the main outcomes of this work package.
WP5.1 (multi-functional trailing edge devices) is a numerical assessment activity which began by defining both 2D and 3D Computational Fluid Dynamics (CFD) benchmarks for the study of various applications for different trailing edge Active Flow Control (AFC) concept devices. This benchmark was defined using results obtained during the previous FP6 “AVERT” project. During AFLoNext, the partners of WP5.1 have performed various CFD assessments against this benchmark, using several different test cases to predict the performance of fluidic Gurney flap and micro-circulation control devices. Iteratively, these results have been shared with other subtasks to identify the most promising application (buffet control) for experimental investigations. Similarly, the experimental results of WP5.2 were fed into the numerical assessments. As well as providing the aerodynamic requirements to generate aircraft-level architecture concepts to implement trailing edge control on a single aisle airliner. The overall results of WP5. 1 have been concluded via two reports; (i) Report on the parametric investigation of circulation control using a fluidic Gurney flap and (ii) Report on the identification of a reduced order model and the closed loop control of buffet by a pulsed fluidic TED.
WP5.3 (hardware and systems implementation concepts) produced five conceptual architectures for installing the most promising TEDs for use in buffet control at the trailing edge. These were informed by the numeric and experimental results performed earlier in the work package and were based on two different slot configurations, upper surface blowing and lower surface fluidic Gurney flap. Buffet control (specifically mach buffet margin reduction) was agreed by the project team as the best application for the purposes of the AFLoNext goals. Increased lift, drag reduction and gust load alleviation are also deemed to be appropriate applications for further research.
Hazards arising from system failures were assessed for each architecture, including hazards arising from environmental threats. This included preliminary Functional Failure Modes and Effects Analysis and the challenges associated with safety assessment and certification. The suitability of the concepts for integration into the representative future reference aircraft were assessed in detail, including compatibility with the flight control systems, system power weight and volume.
The final subtask of work package 5 was the analysis and multi-disciplinary assessment of the most promising architectures, with the aim of identifying the “real world” benefit to the aircraft of such a Trailing Edge Device (TED) system. The scope of this assessment was to use a rapid low order methodology developed by Airbus to estimate buffet margin. The wing design space was investigated using and Airbus developed Aircraft technology evaluation tool, based on the single aisle use case (Mach=0.78 ToC=35,000ft, 3000nm, Payload=17,250kg). The parameters used for investigating the wing design space were as follows: planform constants Λ0.5 t/c, ηcrank ; planform variables, span, taper, area. The study was limited to aerodynamic buffet onset (i.e. no account was made of structural excitation). Wing span loadings were calculated assuming that the Centre of Lift remains constant for CL range of interest. It was assumed that buffet is initiated when local sectional Cl exceeds a specified value (function of Mach, sweep, thickness & design philosophy).
The assessment of FTED for Buffet control was successfully carried out utilising data from across the WP5 partnership. The study examined a range of wing planforms for a typical Single Aisle aircraft mission, with buffet delay and mass flow requirements derived from 2D experimental and validated CFD data provided by WP5.1 and 5.2. System weights utilised trades developed in WP5.3. High span small area wings with flow control are identified as giving fuel burn benefits, with the benefit of the control reducing with increased wing area. Space allocation issues have been identified as challenging and will require significantly higher nominal pressure ratios. A possible weakness of the analysis is that the mass flow calculation is based on 2D data. Recent studies (e.g. CS “Bucolic”) have indicated a strong span-wise buffet development for swept wings. This span-wise effect could be exploited to potentially reduce the mass flow required for buffet control. However, this is not thought to be sufficient to invalidate the conclusions of the WP5.4 study.
Project Results:
Flight test foreground
The ownership of the FTI equipment remains to the providing Party.
The ownership of the VTP will remain to DLR.
A8.2.2. Icing wind tunnel Foreground
All icing wind tunnel Foreground is jointly owned by the Parties listed in article A8.1.2.1 and A8.1.2.2
For the avoidance of doubt all other wind tunnel test Foreground is owned by the performing Party.
A8.3 Access Rights
A8.3.1 Access Rights to flight test Foreground
All F/T Foreground collected during flight will be processed before distributed to the participating Parties
listed in article A8.1.2 , hence no raw data will be delivered. The reason is simply to prevent any data misunderstanding and misinterpretation. The aircraft basic FTI system collects a large set of asynchrony parameters which are stored e.g. on ARINC as a function of the sampling time. In the post processing
step the aerodynamically necessary data will be post processed and synchronized with the FTI data collected by the various FTI systems of WP1 and WP3. Even for aero acoustical purpose the time signals of the measured ARINC parameters have to be synchronized with the noise measurements on ground.
Every Party listed in article A8.1.2 is granted Access Rights to the post processed Foreground of the WP the Party is involved in. The gathered and post processed Foreground will be delivered in an agreed data format.
EADS-U and TsAGI is granted Access Rights to the following WP1 F/T Foreground:
1. F/T Pressure distributions of the two pressure sections (one above and one below the
HLFC-panel) post-processed and synchronized with Ma, Re, AoA, side slip angle, rudder
deflection angle 2. From F/T data generated pressure distribution in the 50% span section of HLFC-panel (middle of the HLFC-panel in line of flight)
3. Transition locations derived from IR-images for both sides and all three Cp sections
4. ASCII data set with the following information per selected flight test point:
HEADER-INFORMATION: CHORD, PHI_EFFECTIVE, PHI_LE, PHI_TE, RE, MACH, TEMPK TABLE OF: X/C, Z/C, CQ, CP
(X/C & Z/C represents the line of flight cross section of the CP-station)
5. VTP-planform geometry
6. Location of HLFC-panel in the VTP-planform geometry
From the recorded F/T data post processed EADS-U will be delivered with processed hot film data signals from the F/T devoted to the verification of the EADS_U device. In principle all post processed F/T Foreground of one level 2 WP is available on request to all Parties participating in this level 2 WP and participating to the F/T cost share.
.
Parties not listed in article A8.1.2 but Member of the AFLoNext Consortium will not have Access Rights to any F/T Foreground.
A8.3.2 Access Rights to icing wind tunnel Foreground
Each Party listed in article A8.1.2.1 or A8.1.2.2 is granted Access Rights to the icing wind tunnel
Foreground.
Parties not listed in article A8.1.2.1 in case of Kruger test performing or in A8.1.2.2 in case of not
performing Kruger test but Member of the AFLoNext Consortium even if affiliated to Parties listed in
article A8.1.2 will not have Access Rights to any icing wind tunnel test Foreground.
A8.3.3 Dissemination restrictions of flight test Foreground
Restriction for publication of F/T Foreground
a) Any first publications of F/T Foreground of a specific WP are limited to the Parties listed in article
A8.1.2 which are involved in this specific WP in which the F/T Foreground is generated.
b) Parties not involved in a specific F/T WP are not allowed to publish any F/T Foreground of this
specific WP except such F/T Foreground has already been published or if the Parties involved in
the said WP unanimously agree on data publication of such F/T Foreground.
A8.3.4 Dissemination restrictions of icing wind tunnel test Foreground
Restriction for publication of icing wind tunnel test Foreground:
a) Any first publications of Foreground are limited to Parties listed in article A8.1.2.1 in case of
Kruger test performing or in A8.1.2.2 in case of not performing Kruger test.
b) In any case Parties involved in A8.1.2.1 or A8.1.2.2 have to request approval to the other Parties
involved in A8.1.2.1 or A8.1.2.2 before any first publication.
c) If explicit negation to publication is not provided within thirty (30) calendar days it is assumed that
approval to publication is provided.
A8.4 Access Rights for Use of Foreground
A8.4.1 Access Rights for Use of flight test Foreground
Any Use of the produced F/T Foreground of a specific WP for research outside of the AFLoNext Project
requires the permission of the participating Parties as listed in article A8.1.2 and as involved in the said
WP. Any Party planning to Use the F/T Foreground outside the AFLoNext Project has to specify the
purpose and has to officially request permission to Use the F/T Foreground for the specified purpose.
Any other Use of the F/T Foreground is prohibited.
The F/T Foreground is open for internal Use to a Party (as defined in article A8.1.2) according to the
conditions set out in article 9 of the Consortium Agreement and after the payment of their individual cost
share (in accordance with article A8.1.2) has been received by the performing Party.
Parties not involved in WP4.1 or WP4.2.1 are not allowed to Use any F/T Foreground achieved within the
respective WP4.1 or WP4.2.1 where they belong to.
[AFLoNext] Consortium Agreement, version 4 [ 2013-09-12]
Version: FTGG-082/13_v4 107 / 107
A8.4.2 Access rights for Use of icing wind tunnel test Foreground
The icing wind tunnel Foreground is open for internal Use to a Party (as defined in article A8.1.2.1 and
A8.1.2.2.) according to the conditions set out in article 9 of this Consortium Agreement and after payment
of their individual cost share has been received by the performing Party.
Potential Impact:
3.1 Expected impacts listed in the work programme
AFLoNext clearly addresses the activity Greening of Air Transport in the Eco-innovation challenge set out in the work programme for aeronautics and air transport. The proposed research activity is expected to have a strong strategic impact since it contributes directly and indirectly to the development and implementation of the European policies as described by the following:
· Competitiveness of aeronautics’ market: Knowledge and economic development
· Solving societal problems:
➢ Environmental impact
➢ Quality of life of European citizens
➢ Impact on employment
➢ Impact on employee's skills and working conditions
➢ Safety issues
Competitiveness of the European aircraft industry
According to current projections by Airbus [1] and Boeing [2], the air traffic worldwide will increase by 5% annually over the next twenty years. This represents a doubling of air traffic every fifteen years. Currently, the airlines are replacing older aircraft with newer, more fuel-efficient ones so that the total demand on jet fuel has increased only slightly. However, by 2020, mid- and older-generation aircraft will represent only 5% of the fleet in service [1], and the benefits of fleet rejuvenation based on the technologies of the latest aircraft generation, i.e. the A320 NEO / B737MAX, A350XWB / B787, and the A380 aircraft, will come to an end. At that point, without the introduction of new technologies, any increase in air traffic will directly result in a corresponding increase in atmospheric pollution.
It is expected that most of the air traffic growth will occur in the emerging markets [3], especially in China and in India. Any legal limitation of air traffic would be seen as affecting the development of these countries, and thus be unacceptable to them. Therefore, it is better to avoid regulations by developing new technologies that offer sufficient fuel-burn reduction to offset future growth in air traffic.
Based on this understanding the project focuses on the integration and maturation of promising flow-, load- and noise-control technologies which provide not only on today’s aircraft configurations already significant emissions reductions but being moreover an enabler for the design of novel aircraft configurations which themselves provide then a breakthrough in eco-innovation. Additionally, as a consequence of the integrative and strongly targeted approach in AFLoNext the European aircraft industry goes one step beyond the competing, non-European developments.
The technologies under investigation within AFLoNext are of a generic nature insofar, that they are applicable to the full range of aeronautical products. Focusing on large civil transport aircraft, the AFLoNext’s technologies can be also fully exploited for regional and business jet aircraft. This is reflected in the consortium set-up which includes the airframe manufacturers Airbus, Dassault-Aviation and IAI. Together, these aircraft manufactures representing well the complete spectrum of commercial aircrafts.
Another major outcome of the project will be advanced design guidelines for the integration of the investigated technologies. Moreover for the whole production process of required structural components and systems related hardware and software for the different technologies, specifications will be compiled and advanced manufacturing principles matured and qualified. This together will strengthen the capabilities, knowledge and the competitiveness of several industries related to aircraft design, ranging from small to large sized companies:
· Aircraft designers and manufacturers
· Systems architects
· Component and materials manufacturers
· Customers like airlines
It is therefore not surprising that the project could inspire so many major key suppliers and manufactures in aircraft industry in Europe like Sonaca, GKN, Cassidian, TAI, Messier-Bugatti-Dowty, BAE Systems, Fokker and others. The impact of AFLoNext on European industry is further widened through the involvement of SMEs for well-directed high-tech products and also small to medium sized companies acting as sub-contractors to the project under the technical leadership of the airframe manufactures and major key suppliers. The strong participation by Research Establishments in the project guarantees, that advanced design guidelines for technologies at high maturity levels are elaborated in a balanced composition between deep scientific investigation and industrial commitment to deliver.
The airlines as customers of an advanced future product (lower emissions, quieter) will profit from AFLoNext’s achievements directly since it enables the maturation of commercial projections of fleet operational costs into near-term future in terms of refined “Direct Operational Costs” or “Cash Operating Costs” (DOC, COC).
The economic impacts expected by the partners of the project are depicted in some detailed examples in the following for the whole product development process (industry, SMEs and research establishments):
For industry:
All of the technologies developed in AFLoNext are of particular importance for Airbus such as they are seen as enablers for the design of novel aircraft configurations which will provide a step change in the environmental compatibility of civil aircraft transport. The strong commitment by Airbus to achieve the challenging eco-innovation targets for future aircraft reveal the significance of AFLoNext regarding the expected economic impact on Airbus’ business.
The participation in the AFLoNext program increases ASCO’s know-how on Krueger flap development, where a significant amount of work has already been done on in the frame of numerous R&D programs (“DESIREH”, “AWAHL”, “DEAMAK”). Until now, Krueger flap developments were focussed on the flap itself. AFLoNext will allow ASCO to complement this work by allowing further work on the design and build of the actuation linkage needed for the Krueger flap, which is seen as the most mature “Leading Edge” (LE) high-lift system compatible with laminar wings, replacing current slats at least to an important extent. It is therefore obvious that AFLoNext will sustain ASCO’s status as world leader in LE actuation mechanisms by the design and manufacturing experience gained in the project.
AFLoNext enables AERN to be a key partner with strong manufacturing expertise to the re-design task of a landing gear door in WP3. With the knowledge gained in the project, AERN will be put in the forefront of European manufactures of advanced landing gear doors (less weight and low vibrations) which then owns also good design knowledge for landing gear doors. Therefore AERN expects a strengthening of their future market representation, this with a focus on potential re-design activities to come for existing Short- and Long-Range aircrafts, new developments like the A320NEO or even future aircrafts like the A30X.
For SMEs:
ACQ as an SME has over 25 years of experience and has developed and produced several avionics solutions, hardware and software, such as electronics for a dynamic airborne monitoring system and a serial actuator. Within AFLoNext, ACQ leads the design, manufacture and testing of an autarkic “HLFC verification systems” (HVS) and contributes to the specification of the flight test instrumentation. As the HVS can be used for several applications, the turnover of ACQ is expected to grow.
For research establishments:
The know-how and the competencies acquired in AFLoNext enables CIRA to further strengthen its position as being a reliable and capable partner for future support and collaboration with industrial partners in the areas of suction chamber design and the design of “Anti Attachment Line Contamination Device” (ACD) and “Wing Ice Protection Systems” (WIPS). This issue also positively affects the European aircraft industry employment rate.
Specifically focusing on the application of the HLFC technology on wing, AG UK sees the opportunity to assess a novel means delaying “Attachment Line Transition” (ALT) on a swept wing through flight testing. AFLoNext also allows for the opportunity to further develop a methodology for more efficient HLFC design accounting for wing shape and suction. This builds on previous research carried out not only on EC level but also in UK National projects like “SAWoF” and “APART”. A successful flight test of the device for ALT delay could lead to an industrialisation for application to current and future aircraft potentially increasing competiveness of AG UK products. Moreover the participation of AG UK will enable the Airbus DS G (Innovation Worksoffice) to further grow the size of its research team and increase its engagement with National and EC research organisations. Moreover other business units like Eurocopter and Cassidian will certainly benefit from Airbus DS G (Innovation Works) providing and sharing technological ideas, experiences and expertises gained within AFLoNext.
Impact on other industrial sectors
There are tasks in AFLoNext which are in terms of mechanical and systems engineering of generic nature so that they could serve as essential elements for other industrial areas too. For instance the results and the experience which will be gained in AFLoNext around the manufacturing and processing of large titanium sheets, including forming process, welding and drilling of the sheets by means of laser or electron beam technology provide a valuable set of high-tech knowledge for metallic light-weight structural design. The same holds for the developments of advanced multi-material and CFRP based design solutions such as the composite HLFC skin with intrinsic porosity proposed by DLR and GKN. Such design principles serve perfectly for other industrial areas too like the automotive industry (light-weight vehicle body) or the energy industry (wind turbine blades). The HVS developed in AFLoNext is also a multi-purpose device which is able to bring improvements to a wide variety of industrial sectors. The developed noise and vibrations mitigation technologies in AFLoNext are good candidates for further exploitation in the automotive and railway industry.
Impact on the Environment
The European aeronautical vision 2020 has set extremely high demanding environmental targets for the aircraft industry (referring to “ACARE”, the Advisory Council for Aeronautical Research in Europe):
• Reduce fuel consumption and CO2 emissions by 50% per passenger kilometre
• Reduce NOx emissions by 80%
• Reduce perceived noise by 50%
• Make substantial progress in reducing the environmental impact of the manufacture, maintenance and disposal of aircraft and related products
The AFLoNext project supports the achievement of these objectives through a holistic approach which aims at demonstrating promising technologies for improved environmental compatibility of the aircraft through a multidisciplinary design and assessment process which considers the net benefits of each technology on fully operational aircraft level.
Table 3-1 shows summarized the quantified benefits of the technologies investigated in AFLoNext to the targets given in the work programme.
Technology Stream (TS) Projected benefit of each Technology Stream
HLFC technology (TS1) 9% fuel saving and corresponding emission reduction
AFC on outer wing (TS2) 2% fuel saving and corresponding emission reduction
AFC on wing/pylon junction (TS3) Enables the effective integration of UHBR engines which alone provides an enormous fuel saving potential. On top, AFC on wing/pylon junction balances a 5% lift loss caused by UHBR integration. Thereby further fuel saving potential through avoidance of wing increase (drag avoidance)
AFC on wing trailing edges (TS4) 1-2% fuel saving and corresponding emission reduction
Technologies to mitigate airframe noise (TS5) All measures together 2-3 EPNdB noise reduction
Technologies to control vibrations in undercarriage area (TS6) Aircraft weight reduction in the order of 100-200 kg
Table 3.1 1: Quantified benefits of the technologies investigated in AFLoNext
Impact on employment
The employment impact flowing from this proposal will affect two areas: firstly, employment within the European aerospace manufacturing sector and secondly, employment within European airlines. Both of these sectors combined employ one million people in about 7000 companies. The EC has been notably successful in both of these sectors and with world air travel projected to grow at 5% per annum over the next 20 years, the combined industry looks set to double within that period. Total direct employment in aeronautics industry represents more than 400,000 people. This number depends on one hand on external factors that influence the air traffic and, consequently, the aircraft manufacturing activity and, on the other hand, on the European share of the market. Employment in Europe in the aircraft-manufacturing sector is very sensitive to market forces. For larger commercial aircraft, there are only two major manufacturers: Airbus mainly based in Toulouse and Hamburg, and Boeing mainly based in Seattle, USA. For regional aircraft, the major players within Europe are in competition with manufacturers primarily in Northern and Southern America, while new competition currently emerges from manufacturers in Russia (Suchoi) and China (COMAC). With so few producers and airlines being willing to purchase internationally, competition between them is understandably fierce. At the level of the aircraft system producer, there is the added competition resulting from international mobility in that the airframe assembler will source on a worldwide basis. AFLoNext will further develop the competitiveness and the employment rate attained by companies of the European aerospace sector in the global market. This will be achieved by innovative aircraft design which satisfies the requirements of future air transport and which show at the same time an extremely high degree of environmental compatibility.
Cultural change: employees skills and education
While the airframe manufacturers and their key suppliers are able to subsequently transform the RTD work conducted in AFLoNext into concrete products, the longer term strategic objective of any collaborative project has to be to secure the future education of high quality aeronautical engineers. For this purpose, academic partners feature strongly within the project. Besides the direct involvement of students within the project, research centers and academic involved in the project will produce education and training material for lectures and courses on the six technology streams. These courses may be held at and by the participating Universities or other interested Education facilities (as described in section 3.2.1). Furthermore, L-UP and the WP leaders take responsibility to raise public awareness and interest in AFLoNext developments through public forums, internet presence and the projects participation to a major aeronautical trade fair. In this manner, young people throughout Europe are expected to be attracted to aeronautical engineering.
These scientists have also to learn to work at EU level. Historically the aerospace industry has developed larger and larger programs. For that it had to progressively join forces. In Europe it was done first at national level and later at a larger scale. Today the aerospace industry ranks amongst the largest manufacturing industries in the world in term of people employed, size and duration of programs and value of output. The traditional technological leaders since the end of Cold War, Europe and the USA, are seeing competition growing from emerging countries. Europe can only keep technological advantage with coordinated efforts. Only a European approach, superseding local or national approach, can then maximise research output that the European industry needs to remain technological leader together with the USA.
Safety issues
It is the fundamental goal of AFLoNext to improve the energy optimisation of the aircraft through the design integration of highly qualified technologies for flow-/load- and noise control without compromising aircraft’s safety. Moreover the integration of these technologies contributes to an improved aircraft performance guarantee of the aircraft by further reducing the remaining performance scatter through the overcoming of unwanted and poorly predictable flow phenomena. In addition the investigated technologies for load and vibrations control in AFLoNext contribute directly to the reduction of the loads level and the durability of airframe and landing gear components (such as landing gear doors) which improve the safety on structure level.
Quality of life and social issues
The aircraft industry has experienced a spectacular growth over the past decades and the consensus of forecasts is for a further doubling of air traffic in the horizon 2020. This massive growth, coupled with the reduced real-terms cost and increased ease of air travel, has today resulted in the spectrum of flying public. The ultimate challenge here is to accommodate this enormous increase in volume of air traffic to densely populated areas around airports to limit the cumulated noise exposure on residents. AFLoNext aims at maturing and integrating promising flow control technologies which either directly reduce airframe noise or does it indirectly through the increase of the aerodynamic performance of the aircraft. An increase in aerodynamic performance enables for instance the aircraft to climb faster or to achieve higher climb angles which in turn reduce the take-off noise and the noise footprint in the vicinity of an airport. An improved aerodynamic performance is also the crucial enabler to further optimize low noise approaches.
List of Websites:
www.aflonext.eu
AFLoNext is a four-year EC L2 project with the objective of proving and maturing highly promising flow control technologies for novel aircraft configurations to achieve a quantum leap in improving aircraft’s performance and thus reducing the environmental footprint. The project consortium is composed of forty European partners from fifteen countries. The work has been broken down into seven work packages. The AFLoNext concept is based on six Technology Streams which cluster the targeted technologies and their associated contributions to advanced aircraft performance as follows:
(1) Hybrid Laminar Flow Control (HLFC) technology applied on fin and wing for friction drag reduction and thus performance increase in cruise conditions.
(2) Flow control technologies to enable more aggressive outer wing design for novel aircraft configurations, thereby improving the performance and the loads situation in low and high speed conditions.
(3) Technologies for local flow separation control applied in wing/pylon junction to improve the performance and loads situation mainly in take-off and landing conditions.
(4) Technologies to control the flow conditions on wing trailing edges thereby improving the performance and loads situation in the whole operational domain.
(5) Technologies to mitigate airframe noise during landing generated on flap and undercarriage and through mutual interaction of both.
(6) Technologies to mitigate/control vibrations in the undercarriage area which are caused by highly unsteady or inhomogeneous inflow conditions in take-off and landing conditions.
AFLoNext aims to prove the engineering feasibility of the HLFC technology for drag reduction on fin in flight test and on wing by means of large scale testing. The project shows also engineering feasibility for vibrations mitigation technologies for reduced aircraft weight and noise mitigation technologies.
The peculiarity of the AFLoNext proposal in terms of holistic technical approach and efficient use of resources becomes obvious through the joint use of a flight test aircraft as common test platform for the above mentioned technologies.
To improve aircraft performance along the whole flight regime, locally applied active flow control technologies on wing and wing/pylon junction are qualified in wind tunnels or by means of lab-type demonstrators.
Project Context and Objectives:
WP1 - Hybrid laminar flow control (HLFC)
WP1.1 - Simplified HLFC-Operation Demonstration
The HLFC leading-edge was successfully manufactured by Airbus. Airtightness test and function test were performed and passed at DLR.
During the A2 F/T performed end of November 2017 unexpected vibrations of the HTP occurred which led to required modification on the HTP camera fairings. Since DLR received new Flight Conditions from EASA too late no second flight to validate the functionality of vibration mitigation could be conducted in 2017. A refurbishment phase was done in the following to prepare the A/C for another FT campaign.
The second working party to install the HLFC system and all FTI started in March 2018. Due to the successful validation of the modification of the HTP camera fairings in April 2018, the AFLoNext FT campaign could be started afterwards.
During five flights and 24 flight hours in total the design, manufactured and installed HLFC system could be extensively tested. Some flight tests were combined with WP3. Finally, the flight test was completed in Mai 2018.
The HLFC leading-edge performed well within the complete HLFC-operating envelope. Both active but also passive suction systems provided sufficient under pressure for every test point within the envelope. All FTI-systems worked stable and smooth during the complete flight test campaign.
The second refurbishment of the A/C was done during summer break.
DLR gathered all flight test data and compiled a delivery to the authorised partners. A preliminary data analysis was conducted showing good results and go do agreement with numerical predictions.
WP1.2 - Simplified HLFC Wing Concept Integration
AGI UK updated their laminar transition calculations to consider the measured pressure loss data of the manufactured suction skin that had higher porosity than expected. Corresponding modifications would lead to 50% fewer suction holes than originally assumed which would reduce the manufacturing cost of a second generation demonstrator. AGI UK also used advanced transition prediction methods to investigate the possible impact on transition of the surface distortions predicted from SONACA's finite element model. This predicted surface waviness was found to have only a small impact on the predicted transition location.
ONERA reviewed whether the updated suction distributions would alter the defined surface tolerance requirements. These tolerance requirements were found to be the same as originally predicted.
Overall aircraft assessment of aircraft with HLFC wings based on the AFLoNext WP1.2 concept was done by Airbus. The results showed the technology will be commercially viable if more work is done to reduce manufacturing costs and to reduce the system weight.
After manufacturing the suction skin for the Ground Based Demonstrator, SONACA updated their processes and manufactured higher quality skin panels using the Super Plastic Forming/Diffusion Bonding technique. This second phase of manufacturing showed that very good improvement regarding the the small distortions in the surface of the original skin panel.
Effectiveness of the three alternative structural concepts were reviewed by Airbus with recommendations made for future developments to help them reach TRL6.
Components for the Ground Based Demonstrator manufactured or purchased by ASCO, INVENT, DLR, INCAS, SONACA, TAI and Airbus then delivered to INCAS for assembly. Assembly of Demonstrator went to plan. Deployment of installed Krueger flap tested. The quality of the air system assembly was established using air pressure tests.
New deliverable on hail strike tests and simulation were completed by PW and VZLU. Results showed consistency between predictions of damage initialisation and propagation and test measurements.
The Ground Based Demonstrator was delivered to CIRA, installed in icing wind tunnel test and tested over a range of conditions. Effectiveness of hot air anti-icing system was established.
WP2 - Active flow control on airframe
The major objectives to be achieved in the last period of the project were closely linked to finalize the experimental parts and assess the results of the work package, which are:
− Perform the ¾ scaled wind tunnel test of the engine wing installation situation at the large wind tunnel facility T-101 at TsAGI to support a TRL 4 level demonstration of active flow control in this area of the wing;
− finalize and assess the harsh environment testing of the active flow control actuators at the facilities of INCAS to support a TRL 3 level demonstration on subsystem level
− establish a common comparison of numerical studies made by computational Fluid Dynamics (CFD);
− perform an assessment on aircraft level of the investigated technologies on aircraft level.
− The large wind tunnel test at TsAGI was successfully performed in September 2017 and verified the expected improvement of the flow by fully suppressing flow
separation past the engine-wing junction by application of Pulsed Jet Actuation
(PJA). The application of Synthetic Jet Actuation (SJA) suffered a failure of
the systems in operation that was verified by comparing pre- and post-test
isolated actuator performance measurements. The cause of the failure hasn’t been fully detected and needs further investigations and research in future
projects.
The harsh environment testing was successfully concluded at INCAS in August 2017. Ten different environmental conditions have been investigated, including extreme temperatures, rain, ice, sand & dust, and solid element contamination. In summary, both types of actuators, PJA and SJA,survived all tests aside the sand & dust, which turned out to be the hardest condition for both types of flow control actuators.
In order to assess the viability of CFD methods to predict and design active flow control technologies, a proper comparison of the results of the numerical studies has been performed as well as the transposition on the full aircraft. The comparison of the different CFD based design studies clearly identify preferred ways of application of active flow control for the two-investigated local flow control situations.
On aircraft level, an assessment has been made for the two concerned classes of aircraft, large transport aircraft and business jet aircraft. Both assessments conclude that the active flow control technologies investigated in AFLoNext are able to achieve the required performance requirements within the given limits of air and/or energy supply. As far as the investigations support the conclusion on TRL levels, the industrial assessment on aircraft level confirm a corresponding increase of maturity of Active Flow Control (AFC) technology within the AFLoNext project.
WP3 - Control means for vibration and aeroelastic coupling
Two NLG doors were manufactured and tested on A320 DLR ATRA A/C. Due to aero-elastic loads non-compliance, the affect was that no flight approval was granted. The
NLG door qualification could not be achieved. Hence, NLG door did not fly within AFLoNext WP3 flight test campaign.
Successful integrated F/T planning with WP1 have been done. The WP3 FTI was working as expected and the Permit to fly could be achieved.
Flight test data has been successfully gathered for NLG sandwich door (gathered for further qualification activities) and MLG door without and with devices. The achievement was a solid F/T database for prediction tools validation and device selection.
Furthermore, the flight test was successfully post-processed and analyzed.
The validation of computational analysis tools has also been summarized and reported.
Based on the F/T data and computational analyses, the identification on vibration control methods has been carried out and reported: tuned-mass-damper, deflectors, VGs and Spoiler.
WP4 - Noise control on airframe
WP4.1: Preparation of A320 flight test was done.
All parts were mounted at DLR's ATRA aircraft. Respective substantiation reports were issued by SAFRAN LS and DLR and finally handed over to EASA. Check at EASA is ongoing, up to now no-show stoppers identified.
WP 4.2.1: A320 flap system with porous flap side edge was re-installed at ATRA aircraft. Necessary repair work was conducted by Airbus prior to a/c installation. The flap is ready for flight, paperwork has been compiled by DLR and handed over to EASA.
Flight test general:
Preparations at DLR ongoing, permit to fly was issued at 27.08.2018. Noise flight tests were conducted at Cochstedt Airport. On basis of online evaluated overall sound pressure level data first checks on data quality and validity can be done on site. Offline analysed and corrected overall SPL data and spectral representations of all results will be provided in dedicated reports.
WP5 - Multifunctional trailing edge concepts
The technical activities were formally closed at a technical workshop, hosted by NLR Amsterdam in May 2017. This newsletter contribution summarises the main outcomes of this work package.
WP5.1 (multi-functional trailing edge devices) is a numerical assessment activity which began by defining both 2D and 3D Computational Fluid Dynamics (CFD) benchmarks for the study of various applications for different trailing edge Active Flow Control (AFC) concept devices. This benchmark was defined using results obtained during the previous FP6 “AVERT” project. During AFLoNext, the partners of WP5.1 have performed various CFD assessments against this benchmark, using several different test cases to predict the performance of fluidic Gurney flap and micro-circulation control devices. Iteratively, these results have been shared with other subtasks to identify the most promising application (buffet control) for experimental investigations. Similarly, the experimental results of WP5.2 were fed into the numerical assessments. As well as providing the aerodynamic requirements to generate aircraft-level architecture concepts to implement trailing edge control on a single aisle airliner. The overall results of WP5. 1 have been concluded via two reports; (i) Report on the parametric investigation of circulation control using a fluidic Gurney flap and (ii) Report on the identification of a reduced order model and the closed loop control of buffet by a pulsed fluidic TED.
WP5.3 (hardware and systems implementation concepts) produced five conceptual architectures for installing the most promising TEDs for use in buffet control at the trailing edge. These were informed by the numeric and experimental results performed earlier in the work package and were based on two different slot configurations, upper surface blowing and lower surface fluidic Gurney flap. Buffet control (specifically mach buffet margin reduction) was agreed by the project team as the best application for the purposes of the AFLoNext goals. Increased lift, drag reduction and gust load alleviation are also deemed to be appropriate applications for further research.
Hazards arising from system failures were assessed for each architecture, including hazards arising from environmental threats. This included preliminary Functional Failure Modes and Effects Analysis and the challenges associated with safety assessment and certification. The suitability of the concepts for integration into the representative future reference aircraft were assessed in detail, including compatibility with the flight control systems, system power weight and volume.
The final subtask of work package 5 was the analysis and multi-disciplinary assessment of the most promising architectures, with the aim of identifying the “real world” benefit to the aircraft of such a Trailing Edge Device (TED) system. The scope of this assessment was to use a rapid low order methodology developed by Airbus to estimate buffet margin. The wing design space was investigated using and Airbus developed Aircraft technology evaluation tool, based on the single aisle use case (Mach=0.78 ToC=35,000ft, 3000nm, Payload=17,250kg). The parameters used for investigating the wing design space were as follows: planform constants Λ0.5 t/c, ηcrank ; planform variables, span, taper, area. The study was limited to aerodynamic buffet onset (i.e. no account was made of structural excitation). Wing span loadings were calculated assuming that the Centre of Lift remains constant for CL range of interest. It was assumed that buffet is initiated when local sectional Cl exceeds a specified value (function of Mach, sweep, thickness & design philosophy).
The assessment of FTED for Buffet control was successfully carried out utilising data from across the WP5 partnership. The study examined a range of wing planforms for a typical Single Aisle aircraft mission, with buffet delay and mass flow requirements derived from 2D experimental and validated CFD data provided by WP5.1 and 5.2. System weights utilised trades developed in WP5.3. High span small area wings with flow control are identified as giving fuel burn benefits, with the benefit of the control reducing with increased wing area. Space allocation issues have been identified as challenging and will require significantly higher nominal pressure ratios. A possible weakness of the analysis is that the mass flow calculation is based on 2D data. Recent studies (e.g. CS “Bucolic”) have indicated a strong span-wise buffet development for swept wings. This span-wise effect could be exploited to potentially reduce the mass flow required for buffet control. However, this is not thought to be sufficient to invalidate the conclusions of the WP5.4 study.
Project Results:
Flight test foreground
The ownership of the FTI equipment remains to the providing Party.
The ownership of the VTP will remain to DLR.
A8.2.2. Icing wind tunnel Foreground
All icing wind tunnel Foreground is jointly owned by the Parties listed in article A8.1.2.1 and A8.1.2.2
For the avoidance of doubt all other wind tunnel test Foreground is owned by the performing Party.
A8.3 Access Rights
A8.3.1 Access Rights to flight test Foreground
All F/T Foreground collected during flight will be processed before distributed to the participating Parties
listed in article A8.1.2 , hence no raw data will be delivered. The reason is simply to prevent any data misunderstanding and misinterpretation. The aircraft basic FTI system collects a large set of asynchrony parameters which are stored e.g. on ARINC as a function of the sampling time. In the post processing
step the aerodynamically necessary data will be post processed and synchronized with the FTI data collected by the various FTI systems of WP1 and WP3. Even for aero acoustical purpose the time signals of the measured ARINC parameters have to be synchronized with the noise measurements on ground.
Every Party listed in article A8.1.2 is granted Access Rights to the post processed Foreground of the WP the Party is involved in. The gathered and post processed Foreground will be delivered in an agreed data format.
EADS-U and TsAGI is granted Access Rights to the following WP1 F/T Foreground:
1. F/T Pressure distributions of the two pressure sections (one above and one below the
HLFC-panel) post-processed and synchronized with Ma, Re, AoA, side slip angle, rudder
deflection angle 2. From F/T data generated pressure distribution in the 50% span section of HLFC-panel (middle of the HLFC-panel in line of flight)
3. Transition locations derived from IR-images for both sides and all three Cp sections
4. ASCII data set with the following information per selected flight test point:
HEADER-INFORMATION: CHORD, PHI_EFFECTIVE, PHI_LE, PHI_TE, RE, MACH, TEMPK TABLE OF: X/C, Z/C, CQ, CP
(X/C & Z/C represents the line of flight cross section of the CP-station)
5. VTP-planform geometry
6. Location of HLFC-panel in the VTP-planform geometry
From the recorded F/T data post processed EADS-U will be delivered with processed hot film data signals from the F/T devoted to the verification of the EADS_U device. In principle all post processed F/T Foreground of one level 2 WP is available on request to all Parties participating in this level 2 WP and participating to the F/T cost share.
.
Parties not listed in article A8.1.2 but Member of the AFLoNext Consortium will not have Access Rights to any F/T Foreground.
A8.3.2 Access Rights to icing wind tunnel Foreground
Each Party listed in article A8.1.2.1 or A8.1.2.2 is granted Access Rights to the icing wind tunnel
Foreground.
Parties not listed in article A8.1.2.1 in case of Kruger test performing or in A8.1.2.2 in case of not
performing Kruger test but Member of the AFLoNext Consortium even if affiliated to Parties listed in
article A8.1.2 will not have Access Rights to any icing wind tunnel test Foreground.
A8.3.3 Dissemination restrictions of flight test Foreground
Restriction for publication of F/T Foreground
a) Any first publications of F/T Foreground of a specific WP are limited to the Parties listed in article
A8.1.2 which are involved in this specific WP in which the F/T Foreground is generated.
b) Parties not involved in a specific F/T WP are not allowed to publish any F/T Foreground of this
specific WP except such F/T Foreground has already been published or if the Parties involved in
the said WP unanimously agree on data publication of such F/T Foreground.
A8.3.4 Dissemination restrictions of icing wind tunnel test Foreground
Restriction for publication of icing wind tunnel test Foreground:
a) Any first publications of Foreground are limited to Parties listed in article A8.1.2.1 in case of
Kruger test performing or in A8.1.2.2 in case of not performing Kruger test.
b) In any case Parties involved in A8.1.2.1 or A8.1.2.2 have to request approval to the other Parties
involved in A8.1.2.1 or A8.1.2.2 before any first publication.
c) If explicit negation to publication is not provided within thirty (30) calendar days it is assumed that
approval to publication is provided.
A8.4 Access Rights for Use of Foreground
A8.4.1 Access Rights for Use of flight test Foreground
Any Use of the produced F/T Foreground of a specific WP for research outside of the AFLoNext Project
requires the permission of the participating Parties as listed in article A8.1.2 and as involved in the said
WP. Any Party planning to Use the F/T Foreground outside the AFLoNext Project has to specify the
purpose and has to officially request permission to Use the F/T Foreground for the specified purpose.
Any other Use of the F/T Foreground is prohibited.
The F/T Foreground is open for internal Use to a Party (as defined in article A8.1.2) according to the
conditions set out in article 9 of the Consortium Agreement and after the payment of their individual cost
share (in accordance with article A8.1.2) has been received by the performing Party.
Parties not involved in WP4.1 or WP4.2.1 are not allowed to Use any F/T Foreground achieved within the
respective WP4.1 or WP4.2.1 where they belong to.
[AFLoNext] Consortium Agreement, version 4 [ 2013-09-12]
Version: FTGG-082/13_v4 107 / 107
A8.4.2 Access rights for Use of icing wind tunnel test Foreground
The icing wind tunnel Foreground is open for internal Use to a Party (as defined in article A8.1.2.1 and
A8.1.2.2.) according to the conditions set out in article 9 of this Consortium Agreement and after payment
of their individual cost share has been received by the performing Party.
Potential Impact:
3.1 Expected impacts listed in the work programme
AFLoNext clearly addresses the activity Greening of Air Transport in the Eco-innovation challenge set out in the work programme for aeronautics and air transport. The proposed research activity is expected to have a strong strategic impact since it contributes directly and indirectly to the development and implementation of the European policies as described by the following:
· Competitiveness of aeronautics’ market: Knowledge and economic development
· Solving societal problems:
➢ Environmental impact
➢ Quality of life of European citizens
➢ Impact on employment
➢ Impact on employee's skills and working conditions
➢ Safety issues
Competitiveness of the European aircraft industry
According to current projections by Airbus [1] and Boeing [2], the air traffic worldwide will increase by 5% annually over the next twenty years. This represents a doubling of air traffic every fifteen years. Currently, the airlines are replacing older aircraft with newer, more fuel-efficient ones so that the total demand on jet fuel has increased only slightly. However, by 2020, mid- and older-generation aircraft will represent only 5% of the fleet in service [1], and the benefits of fleet rejuvenation based on the technologies of the latest aircraft generation, i.e. the A320 NEO / B737MAX, A350XWB / B787, and the A380 aircraft, will come to an end. At that point, without the introduction of new technologies, any increase in air traffic will directly result in a corresponding increase in atmospheric pollution.
It is expected that most of the air traffic growth will occur in the emerging markets [3], especially in China and in India. Any legal limitation of air traffic would be seen as affecting the development of these countries, and thus be unacceptable to them. Therefore, it is better to avoid regulations by developing new technologies that offer sufficient fuel-burn reduction to offset future growth in air traffic.
Based on this understanding the project focuses on the integration and maturation of promising flow-, load- and noise-control technologies which provide not only on today’s aircraft configurations already significant emissions reductions but being moreover an enabler for the design of novel aircraft configurations which themselves provide then a breakthrough in eco-innovation. Additionally, as a consequence of the integrative and strongly targeted approach in AFLoNext the European aircraft industry goes one step beyond the competing, non-European developments.
The technologies under investigation within AFLoNext are of a generic nature insofar, that they are applicable to the full range of aeronautical products. Focusing on large civil transport aircraft, the AFLoNext’s technologies can be also fully exploited for regional and business jet aircraft. This is reflected in the consortium set-up which includes the airframe manufacturers Airbus, Dassault-Aviation and IAI. Together, these aircraft manufactures representing well the complete spectrum of commercial aircrafts.
Another major outcome of the project will be advanced design guidelines for the integration of the investigated technologies. Moreover for the whole production process of required structural components and systems related hardware and software for the different technologies, specifications will be compiled and advanced manufacturing principles matured and qualified. This together will strengthen the capabilities, knowledge and the competitiveness of several industries related to aircraft design, ranging from small to large sized companies:
· Aircraft designers and manufacturers
· Systems architects
· Component and materials manufacturers
· Customers like airlines
It is therefore not surprising that the project could inspire so many major key suppliers and manufactures in aircraft industry in Europe like Sonaca, GKN, Cassidian, TAI, Messier-Bugatti-Dowty, BAE Systems, Fokker and others. The impact of AFLoNext on European industry is further widened through the involvement of SMEs for well-directed high-tech products and also small to medium sized companies acting as sub-contractors to the project under the technical leadership of the airframe manufactures and major key suppliers. The strong participation by Research Establishments in the project guarantees, that advanced design guidelines for technologies at high maturity levels are elaborated in a balanced composition between deep scientific investigation and industrial commitment to deliver.
The airlines as customers of an advanced future product (lower emissions, quieter) will profit from AFLoNext’s achievements directly since it enables the maturation of commercial projections of fleet operational costs into near-term future in terms of refined “Direct Operational Costs” or “Cash Operating Costs” (DOC, COC).
The economic impacts expected by the partners of the project are depicted in some detailed examples in the following for the whole product development process (industry, SMEs and research establishments):
For industry:
All of the technologies developed in AFLoNext are of particular importance for Airbus such as they are seen as enablers for the design of novel aircraft configurations which will provide a step change in the environmental compatibility of civil aircraft transport. The strong commitment by Airbus to achieve the challenging eco-innovation targets for future aircraft reveal the significance of AFLoNext regarding the expected economic impact on Airbus’ business.
The participation in the AFLoNext program increases ASCO’s know-how on Krueger flap development, where a significant amount of work has already been done on in the frame of numerous R&D programs (“DESIREH”, “AWAHL”, “DEAMAK”). Until now, Krueger flap developments were focussed on the flap itself. AFLoNext will allow ASCO to complement this work by allowing further work on the design and build of the actuation linkage needed for the Krueger flap, which is seen as the most mature “Leading Edge” (LE) high-lift system compatible with laminar wings, replacing current slats at least to an important extent. It is therefore obvious that AFLoNext will sustain ASCO’s status as world leader in LE actuation mechanisms by the design and manufacturing experience gained in the project.
AFLoNext enables AERN to be a key partner with strong manufacturing expertise to the re-design task of a landing gear door in WP3. With the knowledge gained in the project, AERN will be put in the forefront of European manufactures of advanced landing gear doors (less weight and low vibrations) which then owns also good design knowledge for landing gear doors. Therefore AERN expects a strengthening of their future market representation, this with a focus on potential re-design activities to come for existing Short- and Long-Range aircrafts, new developments like the A320NEO or even future aircrafts like the A30X.
For SMEs:
ACQ as an SME has over 25 years of experience and has developed and produced several avionics solutions, hardware and software, such as electronics for a dynamic airborne monitoring system and a serial actuator. Within AFLoNext, ACQ leads the design, manufacture and testing of an autarkic “HLFC verification systems” (HVS) and contributes to the specification of the flight test instrumentation. As the HVS can be used for several applications, the turnover of ACQ is expected to grow.
For research establishments:
The know-how and the competencies acquired in AFLoNext enables CIRA to further strengthen its position as being a reliable and capable partner for future support and collaboration with industrial partners in the areas of suction chamber design and the design of “Anti Attachment Line Contamination Device” (ACD) and “Wing Ice Protection Systems” (WIPS). This issue also positively affects the European aircraft industry employment rate.
Specifically focusing on the application of the HLFC technology on wing, AG UK sees the opportunity to assess a novel means delaying “Attachment Line Transition” (ALT) on a swept wing through flight testing. AFLoNext also allows for the opportunity to further develop a methodology for more efficient HLFC design accounting for wing shape and suction. This builds on previous research carried out not only on EC level but also in UK National projects like “SAWoF” and “APART”. A successful flight test of the device for ALT delay could lead to an industrialisation for application to current and future aircraft potentially increasing competiveness of AG UK products. Moreover the participation of AG UK will enable the Airbus DS G (Innovation Worksoffice) to further grow the size of its research team and increase its engagement with National and EC research organisations. Moreover other business units like Eurocopter and Cassidian will certainly benefit from Airbus DS G (Innovation Works) providing and sharing technological ideas, experiences and expertises gained within AFLoNext.
Impact on other industrial sectors
There are tasks in AFLoNext which are in terms of mechanical and systems engineering of generic nature so that they could serve as essential elements for other industrial areas too. For instance the results and the experience which will be gained in AFLoNext around the manufacturing and processing of large titanium sheets, including forming process, welding and drilling of the sheets by means of laser or electron beam technology provide a valuable set of high-tech knowledge for metallic light-weight structural design. The same holds for the developments of advanced multi-material and CFRP based design solutions such as the composite HLFC skin with intrinsic porosity proposed by DLR and GKN. Such design principles serve perfectly for other industrial areas too like the automotive industry (light-weight vehicle body) or the energy industry (wind turbine blades). The HVS developed in AFLoNext is also a multi-purpose device which is able to bring improvements to a wide variety of industrial sectors. The developed noise and vibrations mitigation technologies in AFLoNext are good candidates for further exploitation in the automotive and railway industry.
Impact on the Environment
The European aeronautical vision 2020 has set extremely high demanding environmental targets for the aircraft industry (referring to “ACARE”, the Advisory Council for Aeronautical Research in Europe):
• Reduce fuel consumption and CO2 emissions by 50% per passenger kilometre
• Reduce NOx emissions by 80%
• Reduce perceived noise by 50%
• Make substantial progress in reducing the environmental impact of the manufacture, maintenance and disposal of aircraft and related products
The AFLoNext project supports the achievement of these objectives through a holistic approach which aims at demonstrating promising technologies for improved environmental compatibility of the aircraft through a multidisciplinary design and assessment process which considers the net benefits of each technology on fully operational aircraft level.
Table 3-1 shows summarized the quantified benefits of the technologies investigated in AFLoNext to the targets given in the work programme.
Technology Stream (TS) Projected benefit of each Technology Stream
HLFC technology (TS1) 9% fuel saving and corresponding emission reduction
AFC on outer wing (TS2) 2% fuel saving and corresponding emission reduction
AFC on wing/pylon junction (TS3) Enables the effective integration of UHBR engines which alone provides an enormous fuel saving potential. On top, AFC on wing/pylon junction balances a 5% lift loss caused by UHBR integration. Thereby further fuel saving potential through avoidance of wing increase (drag avoidance)
AFC on wing trailing edges (TS4) 1-2% fuel saving and corresponding emission reduction
Technologies to mitigate airframe noise (TS5) All measures together 2-3 EPNdB noise reduction
Technologies to control vibrations in undercarriage area (TS6) Aircraft weight reduction in the order of 100-200 kg
Table 3.1 1: Quantified benefits of the technologies investigated in AFLoNext
Impact on employment
The employment impact flowing from this proposal will affect two areas: firstly, employment within the European aerospace manufacturing sector and secondly, employment within European airlines. Both of these sectors combined employ one million people in about 7000 companies. The EC has been notably successful in both of these sectors and with world air travel projected to grow at 5% per annum over the next 20 years, the combined industry looks set to double within that period. Total direct employment in aeronautics industry represents more than 400,000 people. This number depends on one hand on external factors that influence the air traffic and, consequently, the aircraft manufacturing activity and, on the other hand, on the European share of the market. Employment in Europe in the aircraft-manufacturing sector is very sensitive to market forces. For larger commercial aircraft, there are only two major manufacturers: Airbus mainly based in Toulouse and Hamburg, and Boeing mainly based in Seattle, USA. For regional aircraft, the major players within Europe are in competition with manufacturers primarily in Northern and Southern America, while new competition currently emerges from manufacturers in Russia (Suchoi) and China (COMAC). With so few producers and airlines being willing to purchase internationally, competition between them is understandably fierce. At the level of the aircraft system producer, there is the added competition resulting from international mobility in that the airframe assembler will source on a worldwide basis. AFLoNext will further develop the competitiveness and the employment rate attained by companies of the European aerospace sector in the global market. This will be achieved by innovative aircraft design which satisfies the requirements of future air transport and which show at the same time an extremely high degree of environmental compatibility.
Cultural change: employees skills and education
While the airframe manufacturers and their key suppliers are able to subsequently transform the RTD work conducted in AFLoNext into concrete products, the longer term strategic objective of any collaborative project has to be to secure the future education of high quality aeronautical engineers. For this purpose, academic partners feature strongly within the project. Besides the direct involvement of students within the project, research centers and academic involved in the project will produce education and training material for lectures and courses on the six technology streams. These courses may be held at and by the participating Universities or other interested Education facilities (as described in section 3.2.1). Furthermore, L-UP and the WP leaders take responsibility to raise public awareness and interest in AFLoNext developments through public forums, internet presence and the projects participation to a major aeronautical trade fair. In this manner, young people throughout Europe are expected to be attracted to aeronautical engineering.
These scientists have also to learn to work at EU level. Historically the aerospace industry has developed larger and larger programs. For that it had to progressively join forces. In Europe it was done first at national level and later at a larger scale. Today the aerospace industry ranks amongst the largest manufacturing industries in the world in term of people employed, size and duration of programs and value of output. The traditional technological leaders since the end of Cold War, Europe and the USA, are seeing competition growing from emerging countries. Europe can only keep technological advantage with coordinated efforts. Only a European approach, superseding local or national approach, can then maximise research output that the European industry needs to remain technological leader together with the USA.
Safety issues
It is the fundamental goal of AFLoNext to improve the energy optimisation of the aircraft through the design integration of highly qualified technologies for flow-/load- and noise control without compromising aircraft’s safety. Moreover the integration of these technologies contributes to an improved aircraft performance guarantee of the aircraft by further reducing the remaining performance scatter through the overcoming of unwanted and poorly predictable flow phenomena. In addition the investigated technologies for load and vibrations control in AFLoNext contribute directly to the reduction of the loads level and the durability of airframe and landing gear components (such as landing gear doors) which improve the safety on structure level.
Quality of life and social issues
The aircraft industry has experienced a spectacular growth over the past decades and the consensus of forecasts is for a further doubling of air traffic in the horizon 2020. This massive growth, coupled with the reduced real-terms cost and increased ease of air travel, has today resulted in the spectrum of flying public. The ultimate challenge here is to accommodate this enormous increase in volume of air traffic to densely populated areas around airports to limit the cumulated noise exposure on residents. AFLoNext aims at maturing and integrating promising flow control technologies which either directly reduce airframe noise or does it indirectly through the increase of the aerodynamic performance of the aircraft. An increase in aerodynamic performance enables for instance the aircraft to climb faster or to achieve higher climb angles which in turn reduce the take-off noise and the noise footprint in the vicinity of an airport. An improved aerodynamic performance is also the crucial enabler to further optimize low noise approaches.
List of Websites:
www.aflonext.eu