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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: 248)
Advances in Aerospace Engineering     Open Access   (Followers: 25)
Advances in Space Research     Full-text available via subscription   (Followers: 279)
Aeronautica     Open Access   (Followers: 19)
Aerospace     Open Access   (Followers: 27)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 136)
Aerospace Science and Technology     Hybrid Journal   (Followers: 270)
AIAA Journal     Full-text available via subscription   (Followers: 575)
Air Force Magazine     Full-text available via subscription   (Followers: 6)
Air Medical Journal     Hybrid Journal   (Followers: 3)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 108)
American Journal of Space Science     Open Access   (Followers: 48)
Annual of Navigation     Open Access   (Followers: 16)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 15)
ASTRA Proceedings     Open Access  
Aviation     Hybrid Journal   (Followers: 10)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 6)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 12)
Aviation Week     Full-text available via subscription   (Followers: 117)
Aviation, Space, and Environmental Medicine     Full-text available via subscription   (Followers: 7)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 25)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 25)
Chinese Journal of Aeronautics     Open Access   (Followers: 13)
Control Systems     Hybrid Journal   (Followers: 57)
Cosmic Research     Hybrid Journal   (Followers: 2)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 4)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 17)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 2)
Fatigue of Aircraft Structures     Open Access   (Followers: 7)
Frontiers in Aerospace Engineering     Open Access   (Followers: 7)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 5)
Giroskopiya i Navigatsiya     Open Access  
Gyroscopy and Navigation     Hybrid Journal   (Followers: 180)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 105)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 18)
International Journal of Aeroacoustics     Full-text available via subscription   (Followers: 27)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 13)
International Journal of Aerospace Engineering     Open Access   (Followers: 57)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 13)
International Journal of Aerospace Sciences     Open Access   (Followers: 18)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 1)
International Journal of Aviation Management     Hybrid Journal   (Followers: 4)
International Journal of Aviation Psychology     Hybrid Journal   (Followers: 11)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 3)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 7)
International Journal of Flow Control     Full-text available via subscription   (Followers: 4)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 4)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 6)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 5)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 4)
International Journal of Space Structures     Full-text available via subscription   (Followers: 6)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 1)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 3)
Journal of Aeronautical Materials     Open Access   (Followers: 2)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 5)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 49)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 5)
Journal of Aerospace Information Systems     Full-text available via subscription   (Followers: 1)
Journal of Aerospace Technology and Management     Open Access   (Followers: 2)
Journal of Aircraft     Full-text available via subscription   (Followers: 162)
Journal of Airline and Airport Management     Open Access   (Followers: 6)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 9)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 109)
Journal of Konbin     Open Access  
Journal of Navigation     Hybrid Journal   (Followers: 167)
Journal of Propulsion and Power     Full-text available via subscription   (Followers: 287)
Journal of Space Weather and Space Climate     Open Access   (Followers: 9)
Journal of Spacecraft and Rockets     Full-text available via subscription   (Followers: 425)
Journal of Spatial Science     Hybrid Journal   (Followers: 1)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 3)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 3)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 3)
Life Sciences in Space Research     Hybrid Journal  
Microgravity Science and Technology     Hybrid Journal  
New Space     Hybrid Journal   (Followers: 2)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
npj Microgravity     Open Access  
Population Space and Place     Hybrid Journal   (Followers: 2)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access  
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 6)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 39)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 61)
Propulsion and Power Research     Open Access   (Followers: 17)
Recent Patents on Space Technology     Full-text available via subscription  
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 3)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 22)
Space and Polity     Hybrid Journal   (Followers: 2)
Space Policy     Hybrid Journal   (Followers: 21)
Space Research Today     Full-text available via subscription   (Followers: 37)
Space Safety Magazine     Free   (Followers: 36)
Space Science Reviews     Hybrid Journal   (Followers: 20)
SpaceNews     Free   (Followers: 417)
Transport and Aerospace Engineering     Open Access   (Followers: 2)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 5)
Unmanned Systems     Hybrid Journal   (Followers: 1)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)
Вестник УГАТУ     Open Access  
Journal Cover CEAS Aeronautical Journal
  [25 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1869-5582
   Published by Springer-Verlag Homepage  [2335 journals]
  • An adaptive self-managing platform for cabin management systems
    • Abstract: In the cabin domain, the degree of changeability is an important commercial parameter. This includes customization before initial aircraft delivery as well as in-service cabin rearrangements and upgrades. This requires a highly flexible cabin management system (CMS). Today`s CMSs face this challenge with configurable system architectures offering a vast change domain, however, the change process itself is very time consuming and error-prone. To overcome this issue our approach of an Adaptive Platform will make manual configuration widely dispensable. Thereby adaptivity means that all components of the platform’s software architecture are able to adapt to any CMS instance nearly without human intervention. Most of the system knowledge needed for this purpose, e.g., topology or communication requirements, is autonomously obtained by discovery mechanisms. The adaptive software architecture contains the following: (1) a data-centric communication middleware, (2) management services clearly separated from the application and (3) plug and play mechanisms for the integration of new application software and peripheral devices. Focus of this paper is the management service which abstracts faulty resources and coordinates global system behaviour w.r.t. aircraft’s state. As a proof of concept, an adaptive CMS demonstration system was realized. We think that the proposed architecture will increase the flexibility within the lifecycle of a CMS substantially. In addition, the contained management services raise the application’s abstraction level by disburden it from any management tasks. Further work on this topic may cover evaluation of the adaptive approach for more safety critical avionic systems or incorporate certification aspects such as automated documentation and testing.
      PubDate: 2016-07-23
  • Crash concept for composite transport aircraft using mainly tensile and
           compressive absorption mechanisms
    • Abstract: Abstract Current design concepts for transport aircraft aim at increasing the aircraft efficiency and performance by the introduction of advanced composite materials, such as carbon fibre reinforced plastics (CFRP). These novel transport aircraft designs may show dissimilar dynamic response behaviour due to differences in failure modes and energy absorption characteristics compared with the current transport aircraft designs made of aluminium alloys. For that reason, crash concepts are being developed to utilise the high specific energy absorption of composite materials for predefined load conditions. In the context of this paper, crash concepts for future CFRP transport aircraft were developed in which most of the kinetic energy is absorbed by tension energy absorbers integrated in the cabin and cargo floor, and by crushing energy absorbers integrated in the cabin floor support struts. The developed crash concepts define mainly parallel activation of different crash devices to achieve smooth energy absorption for different crash load scenarios. Crushing of the energy absorbers integrated in the cabin floor support struts is controlled by a novel structural design in this fuselage area. So far, this research is limited to conceptual studies performed on the basis of a generic CFRP fuselage design. Numerical simulations using the explicit finite-element (FE) code Abaqus/Explicit were performed to derive qualitative and quantitative results for an assessment of the crash concepts. A hybrid FE/macro model approach was used that combines typical FE discretisation with macro models for main failure representation. Two different crash kinematics were considered which distinguish between the failure patterns of the frame structure of the lower fuselage shell. The simulation results presented in this paper in terms of energy plots, passenger accelerations, and crash sequences identify favourable crash performance for a load scenario with fully loaded cabin and an impact velocity of 9.1 m/s (30 ft/s). Significant amount of kinetic energy could be absorbed by tension loads. Parallel activation of crash devices resulted in smooth crash kinematics with reduced trigger loads. By utilisation of the cabin floor support strut area as an energy absorption zone, sufficient energy absorption capacity could be provided even for load scenarios with increased impact energies. The results, presented in this paper, are the basis for further detailed research work on this tension crash concept.
      PubDate: 2016-07-22
  • Compressors for ultra-high-pressure-ratio aero-engines
    • Abstract: Abstract A highly efficient, robust compression system is a key part of any high-performance core engine that is to be developed for meeting future low emission requirements, i.e., for significant reductions in CO2, NOx, and other gaseous emissions. Not only does the compression system has to deliver the increased OPR demanded by the thermal cycle. It has to do so more efficiently to avoid excessive increases in cycle temperatures and weight to avoid reducing the benefit from the new cycle. This challenge is made harder, as OPR is increased up to 70:1, as core-engine size will reduce introducing greater threats to efficiency and compressor stability margin through: (1) lower Reynolds numbers that will result in higher blade losses; (2) tip and shroud/seal clearances increasing due to physical size limitations; (3) if manufacturing tolerances are maintained, blade and vane leading edges, maximum thickness, and fillets radii will be relatively larger; (4) the threat of inclement weather, deterioration, and foreign object damage (FOD) will be greater as compressors get smaller; (5) high aspect ratio blade design will be applied to limit the relative weight and length increase due to required pressure ratio increase of the compression system; (6) higher OPR compression systems will require more stability improvement features, such as VSVs, bleeds, and rotor tip treatments. This paper gives an overview of the above issues and how the FP7 integrated project LEMCOTEC is addressing them through CFD simulations, low- and high-speed rig tests, and innovative designs.
      PubDate: 2016-07-07
  • Numerical investigations of aerodynamic properties of a propeller blown
           circulation control system on a high wing aircraft
    • Abstract: Abstract The contribution gives an overview over a wide range of CFD simulations, which were performed in the course of the German collaborative research center 880 to investigate the aerodynamic properties of a complete turboprop powered transport aircraft in landing configuration with a circulation control high-lift system. The main purpose of the contribution is to highlight aerodynamic and flight mechanical aspects of the integration of lift augmentation technologies into the design of a short take-off and landing aircraft concept. In this context, the influence of engine nacelles and thrust on the stall behavior and the following improvements due to the use of a nacelle strake are discussed. Furthermore, static longitudinal and lateral stability as well as the dynamic longitudinal stability are investigated. While circulation control itself has a rather small impact on the stability, the impact of engine thrust in conjunction with circulation control is considerable. In addition, the one engine inoperative case was simulated. For some flow and engine conditions, the resulting yawing moments are more than twice as high as the actual yawing moments due to asymmetric thrust.
      PubDate: 2016-06-28
  • Propeller and inflow vortex interaction: vortex response and impact on the
           propeller performance
    • Abstract: Abstract The aerodynamic operating conditions of a propeller can include complex situations where vorticity from sources upstream can enter the propeller plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor plane and an eight-bladed propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.
      PubDate: 2016-06-23
  • Investigation of an automated dry fiber preforming process for an aircraft
           fuselage demonstrator using collaborating robots
    • Abstract: Abstract High-performance carbon fiber-reinforced plastics (CFRP) see a continuous growth of their share in structural weight. In particular, in Aerospace, this includes the production of large components, where the key issue of significant high costs remains persistent. The Center for Lightweight Production Technologies in Augsburg as a part of the German Aerospace Center (DLR) addresses this problem with solutions for process automation to increase repeatability, process robustness, and cost-efficiency. This paper presents an approach for automated preforming of large CFRP parts by means of collaborative robots. Investigations include process development for robotic handling of large-carbon fiber cut- pieces and validation on a full-scale demonstrator. The experimental verification is focused on a demonstrator geometry that represents a fuselage section of a typical short- to mid-range aircraft. The work is completed by a discussion about the challenges, solution approaches, and observations. The presented semi-automated preforming process with collaborating robots is an important intermediate step on the way to a fully automated production process for large Aerospace parts made of CFRP.
      PubDate: 2016-06-23
  • Assessment of a state-space aeroelastic rotor model for rotorcraft flight
    • Abstract: Abstract The aim of the paper is the assessment of a methodology for the identification of a helicopter rotor aeroelastic operator in state-space form relating airframe motion and blade controls perturbations to corresponding hub loads, as extracted from a high-fidelity rotor aeroelastic solver. It is suited for helicopter flight dynamics stability and real-time commands response analyses, as well as for control laws synthesis.The identification method consists of a three-step process, starting with evaluation of responses to small perturbation harmonic inputs, followed by their spectral analysis and rational form approximation of corresponding transfer functions. Considering a Bo-105-type helicopter, numerical investigation is focused on: analysis of critical parameters affecting accuracy and efficiency of transfer functions identification, interpretation of the additional states introduced by rational approximation, validation of rotor finite-state aeroelastic representation.
      PubDate: 2016-06-15
  • Integration of a visibility graph based path planning method in the
           ACT/FHS rotorcraft
    • Abstract: Abstract This work presents recent progress at the German Aerospace Center (DLR) in landing guidance for helicopter approaches to landing sites without prior reconnaissance. During the project ALLFlight, DLRs research rotorcraft Advanced Control Technology/Flying Helicopter Simulator (ACT/FHS) has been equipped with a sensor suite including a LIDAR sensor, a forward looking RADAR, an infrared camera and a TV camera to provide sensor-based situational awareness. Using the information acquired by the LIDAR, a method for planning an initial flight path from previously unknown landing entry points to the landing point is presented. It is based on a previously developed method using a vehicle point representation, geo-referenced flight surfaces and visibility graphs. A second mode to provide re-planning capabilities in-flight is described. First results of flight tests conducted in 2013 are presented and discussed. Using the data recorded during these approaches, an improved re-planning strategy for the final approach based on so called visibility hulls is presented. This work continues recent research at DLR’s Institute of Flight Systems helicopter department for flight under degraded visual environment (DVE) for a full-scale helicopter.
      PubDate: 2016-06-13
  • Semi-empirical modeling of fuselage–rotor interference for
           comprehensive codes: influence of side-slip angle
    • Abstract: Abstract A semi-empirical and physics-based analytical formulation of the induced velocities generated by the fuselage shell of the Bo105 wind tunnel model in the volume around the rotor is derived from velocity data computed by a panel code. The reduced-order analytical model is several orders of magnitude faster than the panel code and thus is predestinated for use in comprehensive rotor codes. Angle of attacks investigated include vertical descent, shallow descent, level flight and climb to vertical ascent. Side-slip angles range from forward to quartering flight. The analytical induced velocity model can be directly used to account for the inflow at the blade elements and also allows for analytical or numerical integration of rotor wake convection to compute the associated displacements of rotor blade tip vortices travelling downstream within this velocity field. This model will be used to replace a fully panelized fuselage (and thus significantly reduce the computational effort) throughout a simulation with an aeromechanics code to account for the influence of the fuselage (e.g., in a design stage). The usage within an aerodynamics code (e.g., a panel code) reduces the panelization to the rotor blades only, leaving the computation of the fuselage-induced velocities to the model. The focus of this paper is the analytical evaluation of fuselage–rotor interference in side-slip angles on rotor trim controls, using blade element momentum theory. The results are compared to the influence of thrust-induced inflow gradients on rotor trim.
      PubDate: 2016-06-08
  • On the history and prospects of three-dimensional human–computer
           interfaces for the provision of air traffic control services
    • Abstract: Abstract This paper is an essay on the history and prospects of three-dimensional (3D) human–computer interfaces for the provision of air traffic control services. Over the past 25 years, many empirical studies have addressed this topic. However, the results have been deemed incoherent and self-contradictory and no common conclusion has been reached. To escape from the deadlock of the experimental approach, this study takes a step back into the conceptual development of 3D interfaces, addressing the fundamental benefits and drawbacks of 3D rendering. Under this light, many results in the literature start to make sense and some conclusions can be drawn. Also, with an emphasis on the future of air traffic control, this research identifies a set of tasks wherein the intrinsic weaknesses of 3D rendering can be minimized and its advantages can be exploited. These are the ones that do not require accurate estimates of distances or angles. For future developments in the field of 3D interfaces for air traffic control operators, we suggest focusing on those tasks only.
      PubDate: 2016-06-01
  • Bürgernahes flugzeug: testing technology for the high power propeller
           of a wind tunnel model
    • Abstract: Abstract The research project “Bürgernahes Flugzeug (BNF)”, funded by the federal state of Lower Saxony, is set to study future commercial aircraft. Main task is the development of technologies for quiet aircraft with short take-off and landing capability. A wind tunnel model is built for testing the active high-lift system on a semispan wing, equipped with a scaled high power propeller which is driven by an electric motor. The electric motor was specially developed to meet the required high power density. In 2012 and 2013 several measurement campaigns were carried out in the Low Speed Wind Tunnel Braunschweig (NWB) of the German-Dutch Wind Tunnels (DNW). An operation procedure was set for the measurement campaigns, which allowed testing on varying operation points.
      PubDate: 2016-06-01
  • Initial flight tests of an automatic slung load control system for the
    • Abstract: Abstract An automatic slung load control system for the research helicopter ACT/FHS (active control technology/flying helicopter simulator) of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V.) has been developed and initially tested in flight. The external load is suspended from a rescue hoist which was mounted at the ACT/FHS for flight test purposes. For the load motion detection an optical-inertial sensor system was developed. The sensor system provides estimations of the cable length and cable angle as well as cable angle rates for the slung load control system. Flight testing of the sensor system proved that the optical marker is detected consistently and accurately for cable length up to 50 m. Furthermore, the estimated load motion signals can be used for the control system. To demonstrate the overall system’s functionality, an initial control system for damping of the pendulum load motion was designed and flight tested. The automatic function of the control system was effective in damping the load pendulum motion for a fixed cable length. Under piloted control the slung load damping system showed deficiencies. When actively controlling the helicopter, the pilot acted against the control system resulting in an adverse effect in load damping. Overall, for the first time, a slung load control system for a load suspended from a rescue hoist could be demonstrated successfully.
      PubDate: 2016-06-01
  • Numerical investigations of Fenestron™ noise characteristics using a
           hybrid method
    • Abstract: Abstract The present article gives an overview of numerical investigations performed during a research project aimed at in-depth understanding of noise generation mechanisms of a shrouded helicopter tail rotor such as Airbus Helicopters Fenestron \(^\mathrm{TM}\) . Both aerodynamic and aeroacoustic studies are performed based on a full-scale lightweight transport helicopter configuration with detailed geometry of the Fenestron \(^\mathrm{TM}\) and by neglecting of the main rotor downwash effect. Analysis is carried out by using a hybrid method, combining Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation with Ffowcs Williams and Hawkings (FW-H) acoustic analogy. Two representative helicopter flight conditions, namely fast forward flight and hovering, are considered. Thereby, it is intended to assess the influence of cross flow in forward flight condition on the Fenestron \(^\mathrm{TM}\) acoustic property. Effect of turbulence model on the accuracy of noise prediction is also investigated by comparing the Shear Stress Transport (SST) turbulence model with the Scale Adaptive Simulation (SAS). The capability of the applied hybrid methodology is estimated by means of flight test measurements. A good agreement is found between the predicted and measured sound spectra in terms of blade passing frequency (BPF) and its corresponding sidebands for both flight conditions investigated.
      PubDate: 2016-06-01
  • Preparation and execution of the NICETRIP low- and high-speed wind tunnel
    • Abstract: Abstract The present paper reports the preparation and execution of high- and low-speed wind tunnel tests of the tilt-rotor project NICETRIP. Within the NICETRIP project (Novel Innovative Competitive Effective Tilt Rotor Integrated Project), co-funded by the EU, wind tunnel tests were conducted for a heavily instrumented 1:5 scale model of a tilt-rotor aircraft (3.5 m wingspan, 1.48 m diameter rotors) based on the ERICA concept (Enhanced Rotorcraft Innovative Concept Achievement). The current paper provides an overview of the contributions of DLR to the low- and high-speed wind tunnel tests performed at DNW-LLF (German-Dutch Wind Tunnels Large Low-speed Facility) in 2013 and at ONERA-S1MA in 2014. It gives detailed information about the preparation activities, the model hardware and its control, the necessary adaptations for the model preparation at DLR, and results of the ground vibration tests. Additionally, the data acquisition and monitoring during the wind tunnel experiments, the trimming of the model in the wind tunnel and the conducted tests are described, including encountered problems and how they were solved. In the last section, some representative test results are shown.
      PubDate: 2016-04-01
  • Possibilities and difficulties for rotorcraft using variable transmission
           drive trains
    • Abstract: Abstract This publication shows advantages and possible applications for variable transmission drivetrains within rotorcraft. The power requirement of a generic helicopter with constant and variable rotor speed was calculated. Various drive train technologies that support a variable transmission were described. The prospects of this technology, its influence on the dynamic behaviour of a rotor and further areas that need to be investigated extensively are presented. This technology is applicable to some rotorcraft architecture. Requests from the rotorcraft industry underline the necessity for future rotorcraft using variable rotational speeds. However, the A160 or the EC145 and Mi-8 already show the potential of this technique. Reduction of required power of the rotor should be possible and also an extension of the flight envelope towards higher flight speeds, higher altitudes, better manoeuvrability, etc. By using a variable transmission gearbox, turbine and auxiliary units can still be driven at their design point, independent of the current rotor speed. Excessive loads may occur when discrete speed transmission are used. Frictional or fluid transmissions with continuous variable ratio may fail due to overheating. Other continuous concepts are favoured. The design of a variable speed rotor focuses specifically on its dynamic behaviours and on structural and geometrical optimisation to avoid operation at rotational speed resonance frequencies. Morphing structures may support this. Some rotorcraft architectures can benefit from a variable speed rotor technology. It probably will increase efficiency, decrease noise levels, fuel consumption and CO2 production, and the flight envelope may be extended.
      PubDate: 2016-03-31
  • SPYDER: a software package for system diagnosis engineering
    • Abstract: Abstract Modern aircraft systems comprise hardware and software with high complexity. In order to assure an operation at high availability and low maintenance cost, diagnosis functions become essential. These functions detect faults and failures, identify sources of faults and failures and assess the current state of health. A reduction in operating cost, better planning of maintenance actions, and new business cases for operator and equipment manufactures are gained as a result. A systematic approach for the design and test of diagnosis functions supported by an integrated model-based tool chain is introduced in this paper. That is the SPYDER concept, a Software Package for sYstem Diagnosis EngineeRing. Embedded into the general system development process, a stepwise design and test of diagnosis functions is performed. It focuses on failures and starts with failure–effect analysis, continues with sensor placement and proceeds further to configuration and testing. The method has been applied to multifunctional fuel cell systems that are used as illustrative examples.
      PubDate: 2016-03-28
  • Validation of a nonlinear observer implementation for empennage loads
    • Abstract: Abstract The monitoring of aircraft structural loads shows promising potential for improvement in terms of aircraft maintenance. Monitored loads can be used for component specific overload detection and for targeted inspections on ground. This results in a reduction of the necessary on-ground time after in-flight events and consequently in a reduction of maintenance costs. Focusing model-based approaches for loads monitoring, a nonlinear Luenberger observer is adapted for the flight test aircraft UW-9 Sprint. The implementation of the observer structure containing a state and a disturbance observer, as well as the determination of the included feedback gains is explained. Within this article, the Loads Observer method is validated against flight test data, exemplarily for empennage loads. For this purpose, the empennage of the test aircraft is equipped with strain gages. The test equipment and its calibration are described. Regarding the assessment of combined maneuver and gust loads, the flight test execution including the performance of maneuvers in gusty conditions is demonstrated. Finally, the component loads estimation is compared to the loads measurement.
      PubDate: 2016-03-25
  • Economic optimization of cargo airships
    • Abstract: Abstract Historical strengths and weaknesses of airships were investigated to determine a mission suited for airships. The transatlantic cargo mission was selected to take advantage of the high payload and endurance qualities of airships while minimizing the frequency of ground handling. An optimization was performed to minimize the cost per ton mile of the airship with maximum velocity as the variable. Other design parameters were held constant and based on historical airship studies. The cost per ton mile and von Karman efficiency were used to compare the optimized airship designs with other modes of cargo transportation. An airship with a volume of 200,000 m3, which was the volume of the Hindenburg, would achieve a cost per ton mile of $1.03. This value equates to about 85 % the cost of an airplane, and five times the cost of a truck. A graph of von Karman efficiency showed that the airships proposed by this study could occupy a niche market between airplanes and trucks in terms of both efficiency and velocity.
      PubDate: 2016-03-08
  • Numerical assessment of the vibration control effects of porous liners on
           an over-the-wing propeller configuration
    • Abstract: Abstract An over-the-wing position of propellers comes with noise shielding and significantly reduced sound emission to the ground. A drawback of this configuration may be the additional impact due to the passing propeller blades on the airfoil’s surface inducing structure-borne sound in the wing. This structural sound propagates within the wing and the fuselage and can radiate further into the cabin as airborne sound. In order not to trade the advantage of reduced noise transmission to the ground with higher sound pressure levels within the cabin, a remedy is proposed, which consists in placing a poroelastic liner on the wing’s surface below the rotor where the blade tips move closely to the airfoil’s skin. In this work, a numerical approach to assess the effects of porous liners for an over-the-wing propeller configuration is presented. A simplified generic channelwing structure is exposed to pressure fluctuations on its surface which are caused by an over-the-wing propeller. Porous liners are applied to the wing’s surface where the blade tips pass in close proximity. Structural vibrations are determined using the finite element method in frequency domain. Surface data is obtained from CFD computations. The porous material is represented by Biot’s theory.
      PubDate: 2016-03-01
  • Automated manufacturing of large, three-dimensional CFRP parts from dry
    • Abstract: Abstract At present, the manufacturing of large parts from carbon fiber reinforced plastic in aerospace is mostly done by manual labor. One of the objectives of The Center of Lightweight Production Technology in Augsburg, Germany, is to transfer manual production methods into automated processes. This work addresses the process chain starting with dry textiles, via production integrated quality assurance, to a cured part. A gripper system is required to handle the pliable and delicate dry carbon fiber textiles in the preforming process. The project aims to develop such a system and establish an automated application. A final demonstration of the system’s capabilities allows evaluation of the current level of maturity and usability. Sensor technology is to be integrated into the production process for quality assurance purposes. The position and draping of cut-pieces are determined by laser light section technique and fiber angle measurement. This allows detection of process parameters and potential deviations in the production chain. Corrections can be applied early, which offers a clear advantage over the current inspection of the finished component. Yet another focus is the enhancement of the setup for resin infusion. The application of a pre-tailored VAP membrane using a mechanized lay-up system allows for fast, robust and repeatable vacuum bagging with a significant reduction of manual labor. The presentation will give insight to the development of the gripper system, quality assurance measures, and semi-automated vacuum bagging including their current level of maturity.
      PubDate: 2016-02-19
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