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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 98 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 377)
Advances in Aerospace Engineering     Open Access   (Followers: 52)
Advances in Space Research     Full-text available via subscription   (Followers: 377)
Aerospace     Open Access   (Followers: 46)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 262)
Aerospace Science and Technology     Hybrid Journal   (Followers: 334)
Aerospace Scientific Journal     Open Access   (Followers: 6)
AIAA Journal     Full-text available via subscription   (Followers: 889)
Air Force Magazine     Full-text available via subscription   (Followers: 9)
Air Medical Journal     Hybrid Journal   (Followers: 5)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 185)
Annual of Navigation     Open Access   (Followers: 22)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 20)
ASTRA Proceedings     Open Access   (Followers: 1)
Aviation     Hybrid Journal   (Followers: 13)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 6)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 20)
Aviation Week     Full-text available via subscription   (Followers: 298)
Aviation, Space, and Environmental Medicine     Full-text available via subscription   (Followers: 10)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 29)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 28)
Chinese Journal of Aeronautics     Open Access   (Followers: 18)
Ciencia y Poder Aéreo     Open Access   (Followers: 1)
Civil Aviation High Technologies     Open Access   (Followers: 2)
Control Systems     Hybrid Journal   (Followers: 219)
Cosmic Research     Hybrid Journal   (Followers: 3)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 8)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 19)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 10)
Fatigue of Aircraft Structures     Open Access   (Followers: 13)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 10)
Gyroscopy and Navigation     Hybrid Journal   (Followers: 207)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 169)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 32)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 36)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 24)
International Journal of Aerospace Engineering     Open Access   (Followers: 71)
International Journal of Aerospace Sciences     Open Access   (Followers: 26)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 5)
International Journal of Aviation Management     Hybrid Journal   (Followers: 5)
International Journal of Aviation Psychology     Hybrid Journal   (Followers: 16)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 5)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 9)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 9)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 9)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Space Structures     Full-text available via subscription   (Followers: 13)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 2)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 4)
Journal of Aeronautical Materials     Open Access   (Followers: 6)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 21)
Journal of Aerospace Computing, Information, and Communication     Full-text available via subscription   (Followers: 17)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 62)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 12)
Journal of Aerospace Information Systems     Full-text available via subscription   (Followers: 14)
Journal of Aerospace Technology and Management     Open Access   (Followers: 5)
Journal of Aircraft     Full-text available via subscription   (Followers: 238)
Journal of Aircraft and Spacecraft Technology     Open Access  
Journal of Airline and Airport Management     Open Access   (Followers: 8)
Journal of Astrobiology & Outreach     Open Access   (Followers: 1)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 9)
Journal of Engineering and Technological Sciences     Open Access  
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 136)
Journal of Konbin : The Journal of Air Force Institute of Technology     Open Access   (Followers: 2)
Journal of Navigation     Hybrid Journal   (Followers: 208)
Journal of Propulsion and Power     Full-text available via subscription   (Followers: 442)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 2)
Journal of Space Weather and Space Climate     Open Access   (Followers: 23)
Journal of Spacecraft and Rockets     Full-text available via subscription   (Followers: 607)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 6)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 5)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 7)
Life Sciences in Space Research     Hybrid Journal   (Followers: 2)
MAD - Magazine of Aviation Development     Open Access   (Followers: 1)
Microgravity Science and Technology     Hybrid Journal   (Followers: 1)
New Space     Hybrid Journal   (Followers: 4)
Nonlinear Dynamics     Hybrid Journal   (Followers: 18)
npj Microgravity     Open Access   (Followers: 1)
Population Space and Place     Hybrid Journal   (Followers: 6)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 1)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 10)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 42)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 76)
Propulsion and Power Research     Open Access   (Followers: 35)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 2)
RocketSTEM     Free   (Followers: 4)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 23)
Science and Education : Scientific Publication of BMSTU     Open Access  
Space and Polity     Hybrid Journal   (Followers: 2)
Space Policy     Hybrid Journal   (Followers: 26)
Space Research Today     Full-text available via subscription   (Followers: 43)
Space Safety Magazine     Free   (Followers: 46)
Space Science International     Open Access   (Followers: 142)
Space Science Reviews     Hybrid Journal   (Followers: 93)
SpaceNews     Free   (Followers: 624)
Transport and Aerospace Engineering     Open Access   (Followers: 11)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 5)
Unmanned Systems     Hybrid Journal   (Followers: 3)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)
Journal Cover CEAS Aeronautical Journal
  [SJR: 0.499]   [H-I: 6]   [28 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1869-5582
   Published by Springer-Verlag Homepage  [2351 journals]
  • Thank you to our Reviewers
    • Pages: 1 - 2
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-018-0292-5
      Issue No: Vol. 9, No. 1 (2018)
       
  • An automated CFD analysis workflow in overall aircraft design applications
    • Authors: Xiangyu Gu; Pier Davide Ciampa; Björn Nagel
      Pages: 3 - 13
      Abstract: An automated CFD-based analysis process for applications at the early aircraft development stages is presented. The robustness of the implemented process, which relies on a knowledge-based layer implemented into the automated pre-processing step of the geometrical components, allows taking advantage of high fidelity simulations, also for large explorations of the design space. The well-known aircraft configuration DLR-F6 is chosen to verify the automated analysis process. The CFD analysis process is integrated into the DLR multi-fidelity aircraft design environment, which relies on the DLR open source distributed framework RCE, and the DLR central data model CPACS. The overall aircraft design synthesis is performed for a conventional passenger transportation aircraft configuration, by making use of variable fidelity methods for the aerodynamic analysis. The results discuss the impact of employing CFD-based analysis into overall aircraft design applications.
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-017-0264-1
      Issue No: Vol. 9, No. 1 (2018)
       
  • Tactile cueing with active cyclic stick for helicopter obstacle avoidance:
           development and pilot acceptance
    • Authors: Mario Müllhäuser
      Pages: 27 - 37
      Abstract: As helicopters land and takeoff in obstructed areas and on unprepared landing sites, the risk of a collision with an obstacle is high. DLR has implemented a function to provide haptic feedback on the controls of a helicopter as a haptic pilot assistance for obstacle avoidance to evaluate it’s benefits for flying in obstructed areas. The cueing forces are provided in the direction away from the obstacle, and the intensity is a function of the distance to the obstacle. Two different force strategies were prepared for evaluation. The first was a steady, continuously increasing counter force in combination with an increasing spring gradient. The second was a repetitive, rectangular-shaped pulsing force with increasing frequency and amplitude. As a proof of concept, three EC135 pilots experienced in helicopter emergency medical service assessed the acceptability of such a system for operational use in the EC135 ACT/FHS simulator cockpit in DLRs Air Vehicle Simulation Center. It achieved a high level of acceptance. This paper presents the development and evaluation results and gives recommendations for the further development.
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-017-0271-2
      Issue No: Vol. 9, No. 1 (2018)
       
  • Influence of a back-flow flap on the dynamic stall flow topology
    • Authors: C. C. Wolf; A. D. Gardner; C. B. Merz; S. Opitz
      Pages: 39 - 51
      Abstract: Dynamic stall is a major concern for highly loaded helicopter rotors in fast forward flight. The potential of a back-flow flap for dynamic stall reduction is investigated. The flap assembly is mounted on the suction side of a helicopter main rotor-blade airfoil undergoing deep-stall pitch oscillations. Wind-tunnel experiments using high-speed particle image velocimetry were conducted to identify the flow topology and to investigate the flap’s method of operation. A phase-averaged proper orthogonal decomposition (POD) is used to identify relevant flow events and to compare test cases with and without flap. The evolution of the large-scale dynamic stall vortex in the initial phases of flow separation is analyzed in detail. The back-flow flap splits the vortex into two smaller vortices and thereby reduces the pitching-moment peak. This effect can be described through the eigenmode coefficients of the POD. The study closes with an analysis of different pitching frequencies, which do not affect the flap’s method of operation.
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-017-0274-z
      Issue No: Vol. 9, No. 1 (2018)
       
  • Quasi-steady doublet-lattice correction for aerodynamic gust response
           prediction in attached and separated transonic flow
    • Authors: Diliana Friedewald; Reik Thormann; Christoph Kaiser; Jens Nitzsche
      Pages: 53 - 66
      Abstract: A quasi-steady doublet-lattice correction method is used to predict aerodynamic gust responses of two different configurations: a swept wing, the so-called Aerostabil wing, and a transport aircraft configuration, the NASA Common Research Model. The results of the correction method are compared to uncorrected doublet-lattice results, and to results obtained from a nonlinear computational fluid dynamics solver, the DLR TAU-Code. The correction method agrees well with time-marching results obtained by TAU in the limit of dynamically linear gust amplitudes and improves with gust length. In separated transonic flow, an oscillation of the aerodynamic gust response can be computed.
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-017-0273-0
      Issue No: Vol. 9, No. 1 (2018)
       
  • Novel epoxy prepreg resins for aircraft interiors based on combinations of
           halogen-free flame retardants
    • Authors: Thomas Neumeyer; Anika Bauernfeind; Verena Eigner; Claudia Mueller; Kerstin Pramberger; Volker Altstaedt
      Pages: 235 - 248
      Abstract: Heat release and smoke emission are crucial characteristics regarding the burning behaviour of materials used inside the cabin of a commercial aircraft. In this work, an approach to enhance these properties of epoxy novolac-based resin formulations is presented. The phosphorus-based flame retardant DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) is used in combination with inorganic flame retardants to merge different flame-retarding mechanisms. The effects of the single flame-retarding components on the fire behaviour of the neat epoxy resin are investigated at first by cone calorimeter measurements. Following, the interactions of combining (1) DOPO and ATH and (2) DOPO and boehmite are studied systematically. It is shown that the sole DOPO modification effectively reduces the heat release by gas phase mechanisms, but at the same time increases the smoke production tremendously due to the flame inhibition and the resulting incomplete combustion. By adding inorganic flame retardants, this increase in smoke release can be compensated for. Furthermore, the aforementioned combination of DOPO and ATH leads to a synergistic effect on time to ignition. Fire testing on sandwich structures, consisting of prepreg face sheets based on the resin systems described before, reveals that the relevant characteristics to meet fire safety requirements for aircraft interiors can be fulfilled. Additionally, the influence of the modifiers on the thermal and mechanical properties of the cured resins are presented and discussed. The inorganic flame retardants significantly increase the fracture toughness of the originally rather brittle epoxy novolac resins from around 0.5 MPa m1/2 up to approximately 0.8 MPa m1/2 for the boehmite type used and up to 1.0 MPa m1/2 for ATH at a filler loading of 33.3 wt% in both cases.
      PubDate: 2018-03-01
      DOI: 10.1007/s13272-017-0279-7
      Issue No: Vol. 9, No. 1 (2018)
       
  • Dynamic maneuver loads calculations for a sailplane and comparison with
           flight test
    • Abstract: This work presents the results of dynamic maneuver simulations of a sailplane and the comparison with flight test data. The goal of the effort is to extend and validate an in-house toolbox used for loads analysis of free-flying flexible aircraft in the time domain. The underlying aerodynamic theories are the steady vortex lattice and the doublet lattice method with a rational function approximation for the unsteady simulations in the time domain. The structural model comprises a beam model to represent the stiffness properties and a lumped mass model, both are developed using preliminary design methods. Steady aeroelastic trim simulations are performed and used as initial condition for the time simulation of the unsteady maneuvers in which the pilot’s commands, which were recorded during flight test, are prescribed at the control surfaces. Two vertical maneuvers with elevator excitation, two rolling maneuvers with aileron excitation and three aileron sweeps are simulated. The validation focuses on the comparison of interesting quantities such as section loads, structural accelerations and the rigid body motion. Good agreement between simulation and flight test data is demonstrated for all three kinds of maneuvers, confirming the quality of the models developed by the preliminary design methods.
      PubDate: 2018-04-06
      DOI: 10.1007/s13272-018-0300-9
       
  • Dynamic aircraft simulation model covering local icing effects
    • Authors: C. Deiler; T. Kilian
      Abstract: A novel \(\Delta \) -model approach to characterize the changes in longitudinal and lateral aircraft dynamics occuring due to local icing is analytically derived. This model extension is formulated as a separate module in the aircraft flight mechanics simulation and can be used in existing simulation models. Using the former DLR research aircraft VFW 614 ATTAS as example, information about the icing-induced performance and handling degradation is obtained by 3D CFD calculations with numerically generated ice shapes. With the resulting data, \(\Delta \) -model parameters describing a local aerodynamic degradation are estimated. Simulation of the local wing icing influences on the aircraft’s dynamic behavior show the \(\Delta \) -model’s capabilities to cover aerodynamic changes during a de-icing process.
      PubDate: 2018-03-16
      DOI: 10.1007/s13272-018-0291-6
       
  • Unsteady surface pressures measured at a pitching Lambda wing with vortex
           dominated flow and transonic effects
    • Authors: Stefan Wiggen; Ulrich Henne; Christian Klein; Johannes Nuhn; Werner Sachs
      Abstract: In the Transonic Wind Tunnel Göttingen, pitch oscillations were performed with a Lambda wing to study unsteady pressure distributions of vortex dominated flow including transonic effects. The free stream Mach number was varied between 0.3 and 0.7. Small pitching amplitudes of \(0.08^{\circ }\) – \(0.4^{\circ }\) at excitation frequencies up to 40 Hz were used. In this paper, particularly the data of unsteady Pressure Sensitive Paint measurements and unsteady pressure sensors are analyzed. With increasing angle of attack, a suction peak and a shock occur near the leading edge. Then a shock-induced separation triggers the development of a vortex at the main wing. The unsteady pressures show: for lower angles of attack, the transonic influences are dominant. For higher angles of attack, the influence of the vortex becomes of similar magnitude and dominates the behavior of the pressure variations. The shock exhibits, with increasing angle of attack, an inverse motion. For angles of attack beyond the maximum lift, the unsteady pressure distributions and the lift show a significant phase lag, already at very low oscillation frequencies. Compared to subsonic cases, the supersonic region shifts the vortex induced pressures downstream.
      PubDate: 2018-03-09
      DOI: 10.1007/s13272-018-0293-4
       
  • Ice detection by ultrasonic guided waves
    • Authors: C. Mendig; J. Riemenschneider; H. P. Monner; L. J. Vier; M. Endres; Hannah Sommerwerk
      Abstract: This paper describes a method for inflight ice detection using ultrasonic guided waves that is little studied until now. Unlike existing systems, the proposed method can immediately detect icing at the place of formation. The detection area can also include whole structural segments and the proposed sensor can be integrated into a wing structure without any effect on the flow around the aerofoil or increase in drag. The proposed detection method is based on excitation with a burst signal and a sine sweep. The system was tested on a plate made from carbon fibre-reinforced plastic (CFRP) and two leading edges of a NACA 0012 profile. Ice was applied to the CFRP-plate in a cooling chamber using regular water and built up onto the leading edges in an ice wind tunnel using super cooled water droplets. Piezo ceramic patches and discs were affixed to the testing model structures for use as transceivers and receivers, respectively, to initiate the guided waves and convert them back into electric signals. The influence of variation in ice layer thickness and temperature on the sensor output signal was then investigated using the average and maximum absolute sensor output and runtime to calculate the group velocity, which was then compared to calculated group velocity values. Based on the test results, the proposed method was determined to be sensitive to the build-up of ice and, thus, effective in principle.
      PubDate: 2018-03-09
      DOI: 10.1007/s13272-018-0289-0
       
  • Paths to alternative fuels for aviation
    • Authors: Sandra Richter; Marina Braun-Unkhoff; Clemens Naumann; Uwe Riedel
      Abstract: Almost the complete amount of jet fuel available on the global market is produced from fossil crude oil being an exhaustible raw material. Furthermore its use is inherently connected with emissions of the greenhouse gas CO2. To cope with this, several processes for the production of alternative aviation fuels were developed including the use of biomass as a renewable feedstock. Since biomass from cultivation farming is in competition with food and fodder production, the preferred raw material would be residues from agriculture and forestry or municipal waste, also microalgae can be used. Independent of the raw material, the conversion of biogenic feedstock into alternative jet fuel is based on microbial, thermal and/or chemical breakdown of larger (bio)-molecules into smaller ones, followed by the catalytic formation of fuel molecules and hydrogenation. An overview on the production of different alternative bio-based jet fuels is given including a survey about producers and capacities, focusing on already certificated bio-based jet fuels. In addition to that, a comparison of fundamental combustion properties between Jet A-1 and different alternative jet fuels is presented: Laminar burning velocities and ignition delay times, each measured for two synthetic jet fuels based on fossil resources (coal-to-liquid—CtL and gas-to-liquid—GtL) as well as for two biofuels (farnesane and an Alcohol-to-Jet fuel—AtJ). Measurements of the burning velocities were performed at a preheat temperature of 473 K and pressures of 1 and 3 bar by variation of the fuel–air-equivalence ratios φ. Ignition delay times were determined for φ-values of 0.5, 1.0, and 2.0, at an initial pressure of about 16 bar and temperatures ranging between 800 and 1700 K. It turns out that with respect to the characteristic combustion properties tested the considered alternative fuels have a combustion behavior similar to Jet A-1.
      PubDate: 2018-03-09
      DOI: 10.1007/s13272-018-0296-1
       
  • HALO flight test with instrumented under-wing stores for aeroelastic and
           load measurements in the DLR project iLOADS
    • Authors: J. Sinske; Y. Govers; G. Jelicic; V. Handojo; W. R. Krüger; M. Böswald
      Abstract: HALO (High Altitude and Long Range Research Aircraft), the atmospheric research aircraft of the German Aerospace Center (DLR), can be equipped with under-wing stores at different wing positions to transport scientific instruments for atmospheric research. The particle measurement system (PMS) carrier is such an external store which can carry three instruments at the same time per wing. Any modifications on an aircraft must be tested numerically and experimentally to ensure the structural integrity of the aircraft for all flight conditions. Load and flutter analyses can be validated with flight test data. For flight test, the aircraft and the under-wing stores of HALO must be equipped with acceleration and strain sensors. To reduce flight test time it is necessary to make quick decisions during the flight test. Therefore the DLR Institute of Aeroelasticity in Göttingen has developed a real-time analysis procedure for online identification of modal parameters like eigenfrequencies, damping ratios and mode shapes. These parameters vary with flight conditions and are necessary to analyse the aeroelastic stability of the system. The department of loads analysis and aeroelastic design and the department of structural dynamics and system identification have tested the newly developed procedure in 14 flight hours on the HALO. A network of three distributed data acquisition modules enabled the recording of the flight test instrumentation with 51 accelerometers and 16 strain gauge bridges. The measured data were distributed online on several computers where the newly developed software was implemented, allowing an instantaneous analysis of the structural dynamics behaviour and loads in flight. This paper provides an overview of the conducted flight vibration tests with HALO. It also shows the capability of the newly developed online monitoring system for aeroelastic identification.
      PubDate: 2018-02-27
      DOI: 10.1007/s13272-018-0294-3
       
  • A practical example for validation of ATM security prototypes
    • Authors: Michael Finke; Tim H. Stelkens-Kobsch
      Abstract: The insights presented in this article are outcomes of a security research project that was initiated to collate and interpret the latest findings gathered in the domain of air traffic management security. The concept of a holistic approach to security management has been evaluated. Due to the large scope of the project, only an excerpt of the findings is provided in this article. This article focuses on a brief description of a security prototype validation methodology, developed within the project. To provide tangible application of the methodology, the adoption to a security prototype is developed, which is intended to enhance security of the air traffic control voice communication system.
      PubDate: 2018-01-24
      DOI: 10.1007/s13272-017-0275-y
       
  • Evaluation of assemblability during aero engine preliminary design
    • Authors: J. Mall; S. Staudacher
      Abstract: Despite the constant growth of global air traffic, the competition amongst airlines and their aviation supply chains intensifies. In the future, stricter environmental regulations as well as economic goals will only be met by new aircrafts and aero engines. In order to evaluate the life-cycle related cost at an early stage in the product design process, it is essential to assess the manufacturability and assemblability during preliminary design. Through the assessment of assemblability, major cost drivers can be identified in order to optimize the overall production cost. In this paper, a method to assess the assemblability of different preliminary design variants is introduced. To achieve this, 2D cross sections of actual aero engines are translated into 3D preliminary design models. Finally, an evaluation of the assemblability of different design variants of low pressure turbine modules is conducted.
      PubDate: 2018-01-19
      DOI: 10.1007/s13272-017-0278-8
       
  • Comparison of sensitivities to geometrical properties of front and aft
           high pressure compressor stages
    • Authors: G. Reitz; A. Kellersmann; S. Schlange; J. Friedrichs
      Abstract: In modern aviation, the engine-related proportion of the direct operating costs (DOC) is about one quarter. Thereby, the engine-related costs are devided into three roughly equivalent parts: depreciation/financing, fuel and maintenance and overhaul (Rupp in DLRK 2001, 2001). Consequently, an efficient and high technical quality maintenance has a great impact on the DOC. Nowadays, the transition from the exhaust gas temperature based to the condition based maintenance is developing. Thereby, the maintenance, repair and overhaul (MRO) companies provide tailored maintenance actions for each jet engine, depending on the engine history and operation conditions. Obviously, a detailed knowledge of the influence of the different engine components and their features on the engine performance is necessary to accomplish a condition based maintenance. In order to illustrate this, the example of the high pressure compressor (HPC) is shown: The HPC has a strong impact on the gas turbine efficiency and the specific fuel consumption (SFC). Nevertheless, the HPC blading is classified coarsely into serviceable, scrap and repairable. The repairable blades are repaired by a few repair processes, without evaluating the blade geometry in detail. With a detailed knowledge of the geometric main parameters to the aerodynamic performance and their interactions, future repair processes could maintain suited maintenance actions as well as tailored blade sets for the HPC. Therefore, a more efficient maintenance could be achieved to meet future requirements of the costumers. This paper contributes a part to this maintenance development. Therefore, a design of experiments and a sensitivity analysis will be carried out for a HPC-aft stage and compared with previous gained results of a HPC-front stage. Therefore, 700 different stage geometries will be analyzed for their aerodynamic performance and imported to a Kriging Method to generate a meta-model. This meta-model allows a sensitivity analysis for individual geometric properties. The detected sensitivities will be compared to those of the front stage. Changes of the behavior of the stages through the HPC could help the MRO companies to focus on appropriate geometric properties and, therefore, suitable repair processes for each stage and airfoil.
      PubDate: 2018-01-18
      DOI: 10.1007/s13272-018-0281-8
       
  • In-situ structural evaluation during the fibre deposition process of
           composite manufacturing
    • Authors: F. Heinecke; T. Wille
      Abstract: Within the European funded project ECOMISE a new approach for composite manufacturing is developed. This approach provides key technologies for industry 4.0 in order to maximize process efficiency at reduced cost and time while maintaining structural requirements. In detail, process simulation methods, online process monitoring systems as well as methods for in situ structural evaluation and process adjustment in case of process deviations are implemented and linked via databases. This paper describes the new overall concept as well as the specific in situ structural evaluation approach, exemplarily applied to the fibre deposition process. Prior to manufacturing typical manufacturing features such as locally varying fibre orientation, gaps and overlaps are studied based on given knowledge from previous manufacturing as well as from process simulation. The effect of selected features on the structural properties is investigated for the expected parameter ranges. The real detected features are provided by an online monitoring system during the fibre deposition process. Based on these results an in situ structural evaluation of detected features is performed already during manufacturing in combination with a decision making with respect to required part correction. The developed key technologies and tools for the in situ evaluation process are presented, and their prototype application is shown during manufacturing of an aeronautic wing cover demonstrator.
      PubDate: 2018-01-18
      DOI: 10.1007/s13272-018-0284-5
       
  • AAA process: a new approach to affordable fly-by-wire systems for CS23
           aircraft
    • Authors: P. Mueller; T. Belschner; M. Lehmann; R. Reichel
      Abstract: LuFo IV FLYSMART and its predecessor projects succeeded in developing and integrating a full authority fly-by-wire system with ATOL capability on a DA42 of our partner Diamond Aircraft Industries. In the short term, fly-by-wire technology will open up new fields of applications for general aviation aircraft to fulfill complex mission scenarios using the Flexible Platform technology (a platform-based development approach) currently developed at the University of Stuttgart. This technology is the baseline and enables the automatization of certain certification relevant life cycle tasks, thus reducing the effort and, therefore, costs of the development. The new approach presented as following, called the AAA-Process, consists of three automatization complexes. The first complex is the automated design and documentation, the second one is the automated parameter instantiation and SW/SW–HW/SW integration and the last one is automated generation of verification artifacts. This paper introduces these automatization complexes and explains their relationship to the common life cycle process of guidance materials. The AAA-Process lays the foundation for a total system capability regarding fly-by-wire systems for the small aircraft domain while simultaneously reducing risks and costs.
      PubDate: 2018-01-15
      DOI: 10.1007/s13272-018-0282-7
       
  • Unsteady aerodynamics of a diamond wing configuration
    • Authors: Stefan Pfnür; Christian Breitsamter
      Abstract: The damping derivatives associated with the pitching, yawing, and rolling motion of the SAGITTA flying wing configuration at low Mach number conditions are presented. A tailless variant of the configuration and a variant with attached double vertical tail are investigated. The damping derivatives are determined by means of the aerodynamic response to forced harmonic oscillations. The required data for the determination of the damping derivatives are obtained from time-accurate Reynolds-averaged Navier–Stokes computations. The calculation methodology for the pitch-, yaw-, and roll-damping derivatives for arbitrary freestream conditions is described and a short evaluation of the approach is presented. Angle of attack and sideslip angle trends as well as the effect of the double vertical tail on the dynamic stability are investigated. The damping derivative of every considered type of motion exhibits significant non-linearities with respect to the freestream condition for angles of attack larger than \(8^\circ\) . The pitch-damping and roll-damping derivative indicate a dynamically stable behavior at all considered freestream conditions for the configuration with and without vertical tail. The yaw-damping characteristic is more critical. Both configurations exhibit unstable behavior at several freestream conditions. The vertical tail, however, considerably improves the yaw-damping characteristic of the SAGITTA configuration.
      PubDate: 2018-01-12
      DOI: 10.1007/s13272-018-0280-9
       
  • Future regeneration processes for high-pressure turbine blades
    • Authors: M. Nicolaus; B. Rottwinkel; I. Alfred; K. Möhwald; C. Nölke; S. Kaierle; H. J. Maier; V. Wesling
      Abstract: In this paper, new technologies for repairing turbine blades are presented, in which the manufacturing processes and materials mechanisms are incorporated. Since the turbine blades taken into consideration here are components of high pressure turbines, the focus of this paper lies on nickel-based alloys. Depending on the size and form of the defects present on the blades, two procedures can be used for repairing turbine blades: brazing and/or cladding. In one approach, a hybrid repair brazing process was developed, in which the filler metal and the hot gas corrosion protective coating were applied by thermal spraying. Subsequently, a combined brazing and aluminizing process was carried out. In a second approach, a laser cladding process for crack repair was developed wherein single crystalline solidification of the cladding material was carried out.
      PubDate: 2017-12-26
      DOI: 10.1007/s13272-017-0277-9
       
  • About the impact of wind turbine blade tip vortices on helicopter rotor
           trim and rotor blade motion
    • Authors: Berend G. van der Wall; Paul H. Lehmann
      Abstract: With increasing numbers of large wind turbines on-shore and off-shore, interactions of their wake with helicopters become a subject worth investigating. In this paper, the wake is modeled as a tip vortex helix with a vortex strength estimated from the wind turbine thrust. Helicopter rotors of different size and hub layout are subjected to the wake and the collective and cyclic control inputs required to keep the trim are compared to the maximum available control range of the rotorcraft. In addition, the blade flapping response due to the vortex influence without pilot action is computed and compared to maximum allowed flapping angles. It is found that typical on-shore wind turbines could be a hazard for ultralight helicopters, but not for larger helicopters. Large off-shore wind turbines, however, could even be a danger for small helicopters that may be used for maintenance. In addition, the results are compared to fixed-wing wake vortex interaction with a helicopter as given in the literature.
      PubDate: 2017-12-12
      DOI: 10.1007/s13272-017-0276-x
       
 
 
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