Other publications

Permanent URI for this collection

https://reports.nlr.nl/handle/10921/1451
Other than NLR reports

Browse

Browsing Other publications by Title

  • Item
    A challenging high-end data acquisition system in a harsh wind tunnel environment at high rotational speed
    (3AF, 2023) Bardet, S.M. ; Zutphen, W.J.C.M. van ; Fontaine, F.M. ; Faasse, P.R.
    NLR developed an advanced, high-performance data acquisition system for a generic engine test rig. The test rig is intended for wind tunnel use. The RDAS and MDAS subsystems are bespoke developments, supporting a total of 120 rotating and almost 700 stationary measurement channels. All measurements are made under harsh environmental conditions: wide temperature range and high vibration levels. The rotating section tolerates rotation up to 16,000 rpm.
  • Item
    A Heat Pump for Space Applications
    ( 2015) Gerner, H.J. van ; Donk, G. van ; Pauw, A. ; Es, J. van ; Lapensée, S.
    In commercial communication satellites, waste heat (5-10kW) has to be radiated into space by radiators. These radiators determine the size of the spacecraft, and a further increase in radiator size (and therefore spacecraft size) to increase the heat rejection capacity is not practical. A heat pump can be used to raise the radiator temperature above the temperature of the equipment, which results in a higher heat rejecting capacity without increasing the size of the radiators. A heat pump also provides the opportunity to use East/West radiators, which become almost as effective as North/South radiators when the temperature is elevated to 100°C. The heat pump works with the vapour compression cycle and requires a compressor. However, commercially available compressors have a high mass (40 kg for 10kW cooling capacity), cause excessive vibrations, and are intended for much lower temperatures (maximum 65°C) than what is required for the space heat pump application (100°C). Dedicated aerospace compressors have been developed with a lower mass (19 kg) and for higher temperatures, but these compressors have a lower efficiency. For this reason, an electrically-driven, high-speed (200,000 RPM), centrifugal compressor system has been developed in a project funded by the European Space Agency (ESA). This novel 3-stage compressor system has a mass of just 2 kg and a higher efficiency than existing aerospace compressors. The compressor system has been incorporated in a heat pump demonstrator, which uses isopentane (R601a) as refrigerant. Due to the exposure of isopentane to radiation in a space application, other substances will form. However, a literature study shows that the amounts of the formed substances are so small, that no significant influence on the performance of the heat pump is expected. Tests were carried out with the heat pump, and at the target setting (saturation temperature of 45°C at the evaporator, 100°C at the condenser, and a payload heat input of 5 kW), the measured COP is 2.3, which is higher than the original requirement of 2.
  • Item
    A Review on Education and Training Needs for Military Space Operations
    (NTSA, 2024) Caso, S. ; Tanis, T.P. ; Kleef, A.J.P. van
    Space is a dynamic and rapidly evolving domain, driven by the increased engagement across the commercial, scientific, governmental and military sectors. Particularly, operations in low Earth orbit (LEO), medium Earth orbit (MEO) and geostationary Earth orbit (GEO) play a vital role in sustaining infrastructures for daily on-Earth activities, e.g., global positioning system (GPS) and 5G. In 2019, a significant milestone was reached with the adoption of NATO’s Space Policy, officially recognizing space as a distinct operational domain alongside land, air, sea and cyberspace. This integration positioned space capabilities as an integral part to military strategies, supplying vital information for secure operations. Due to the growing dependency of space infrastructures, military personnel must be trained to be able to effectively operate space assets and to be prepared for hostile or environmental calamities. This paper conducted a state-of-the-art analysis of military training needs in the realm of space. A literature review was made, encompassing the current scientific literature in space training, with the latest topics from several space agendas outlined by relevant organizations and countries. In addition, interviews were conducted, complemented by surveys, in order to identify the current training gaps and areas for improvement. The findings identified several research gaps and needs related to training and education tools, with a specific emphasis on the Space Situational Awareness (SSA) and Space Traffic Management (STM) topics. These recommendations were particularly addressed to the recognizing and mitigating of potential calamities, a concern heightened by the dense presence of satellites in the Earth's orbit. Additionally, a training gap was identified within the use of satellite images for Intelligence, Surveillance & Reconnaissance (ISR) activities. These activities play a vital role in supporting military operations with their decision-making processes, by improving situational awareness on land, in air, and at sea. Finally, suggestions were made regarding the use of the latest technological tools.
  • Item
    A systematic literature review of low-cost 3D mapping solutions
    (Elsevier, 2025) Balado Frias, J. ; Garozzo, R. ; Winiwarter, L. ; Tilon, S.M.
    In "low-cost" solutions, ensuring economic accessibility and democratizing the availability of emerging technologies stand as pivotal considerations. This study undertakes a systematic literature review of low-cost 3D mapping solutions. Leveraging SCOPUS as the primary database, a comprehensive bibliometric analysis encompassing 1380 publications was conducted, subsequently narrowing the focus to 87 recent publications for detailed review. This research endeavors to delineate the defining characteristics of low-cost systems, elucidate their principal applications and preferred platforms, assess accessibility level, gauge the extent of innovation in both hardware and software development, explore the contributions of Deep Learning and data fusion, evaluate the consideration of data quality, and examine the contemporary relevance of photogrammetry within low-cost context. The findings demonstrate that many authors subjectively use the term low-cost to highlight qualities of a technology, methodology or sensor, but challenges arise from data quality comparisons with high-cost systems.
  • Item
    Advanced landing gear fibre Bragg grating sensing and monitoring system
    ( 2022) Grooteman, F.P. ; Goutagny, R. ; Davies, C. ; Leest, T. van ; Platt, I. ; Symons, J.
    In this paper an advanced optical-based landing gear load sensing and monitoring system is presented. The system measures strains using fibre Bragg grating sensor that are converted into loads and torque at the landing gear wheels and provides this data for use by the aircraft systems for integration with aircraft health monitoring, hard landing detection, flight management, flight controls and ground controls. A complete sensing system was developed in the European Union Clean Sky 2 Joint Technology Initiative Advanced Landing Gear Sensing and Monitoring (ALGeSMo), described herein. This involved: the integration of optical fibres into a composite structure, the development of an optical harness (cabling and connectors) meeting aircraft installation requirements, the readout of the optical fibre sensors with state-of-the-art miniature optoelectronics and the processing and communication of the data. Apart from specific tests on the various components, a bespoke test rig was developed to rigorously test the whole sensing and monitoring system on an A320 main landing gear slider tube to validate the performance of the system. The system-level tests performed on the test rig showed a very good correlation with applied actuator loads and additional conventional strain and temperature sensors. It demonstrates that loads along all three axis of the landing gear and the torque about the wheel axle can be accurately measured. Tests performed at cold and elevated temperatures, however, revealed that the generally applied one-dimensional temperature compensation equation is not accurate enough for this application, due to the non-uniform non-stationary temperature field. The ALGeSMo research activities have advanced the state of the art in several key areas for the deployment of optical sensing systems for safety-critical applications, such as integration of optical fibres into composite material, robust optical connections, avionic-compliant optical interrogator and landing gear load measurement up to technology readiness level technology readiness level 5.
  • Item
    Advancing safety in organisations: application via the Luton Safety stack
    (MATEC Web of Conferences, 2019) Smeltink, J. ; Stroeve, S. ; Kirwan, B.
    Controlling and improving safety in organisations is achieved using a Safety Management System (SMS). Notwithstanding the variety of components considered in SMS standards, including human factors and safety culture, safety management systems are sometimes observed by those at the ‘sharp end’ as being bureaucratic, distinct from actual operations, and being too focused on the prevention of deviations from procedures, rather than on the effective support of safety in the real operational context. The soft parts of advancing safety in organisations, such as the multitude of interrelations and the informal aspects in an organisation that influence safety, are only considered to a limited extent in traditional safety management systems. The research in Future Sky Safety Project 5 (FSS P5) focused on improving these human-related, informal organisational aspects. Since every organisation is unique, in the operations it conducts, its history, and its organisational culture, there cannot be a one-size-fits-all standard for advancing safety in organisations. Rather, this needs to be based on the organisation at hand, leading to tailored solutions. This has been applied to a safety culture assessment and enhancement approach applied for six key organisations at London Luton Airport, and the approach has become known as the Luton Safety Stack. The six organisations decided to share the detailed results of their individual safety culture assessments. They formed a group that holds quarterly meetings, which always include a workshop element. From this approach, the organisations were stimulated to develop harmonised procedures for all ground-handling operators at Luton, and for each operation, creating a simple one-page procedure with diagrams, to keep it simple and safe. The Luton Safety Stack shows that when organisations share a place, such as at an airport, they need the opportunity to meet to discuss both potential safety threats, and opportunities to advance safety, because even through organisations are interdependent, safety issues in one organisation often have implications for others.
  • Item
    An Assessment of STPA as Applied to the Scaled Flight Demonstrator Test Program
    (SFTE, 2024) MacCafferty, J.P. ; Bumgardner, W.R.
    Systems Theoretic Process Analysis (STPA) is a methodology for system development and safety assessment which builds on the System-Theoretic Accident Model and Processes (STAMP) causality model which approaches safety as a dynamic control problem. The STPA methodology addresses system analysis and safety assessment for systems that involve complex human interactions and high degrees of coupling. The purpose of this paper is to demonstrate the application of STPA to the remotely piloted Scaled Flight Demonstrator (SFD) aircraft test program, and assess the effectiveness for test planning and risk assessment relative to the traditional Test Hazards Analysis (THA) process. The SFD aircraft is a 1:8.5 scaled model of the Airbus A320 which has been modified into a distributed electric propulsion (DEP) configuration. The aircraft was developed in collaboration with members of the Clean Sky 2 program: The Royal Netherlands Aerospace Centre (NLR), Technische Universiteit Delft (TU Delft), The Office national d'études et de recherches aérospatiales (ONERA), Centro Italiano Ricerche Aerospaziali (CIRA), Airbus, and Orange Aerospace. This effort identifies multiple benefits for flight testers when applying STPA to a highly complex system, including: increased knowledge of the system under test, forced collaboration between the test team and system experts, and identification of risks and mitigations that may otherwise be missed. The team also identifies some drawbacks to applying STPA, including: the time investment required to learn and apply the process, and the challenge in identifying specific hardware or software failure modes. Lessons learned and recommendations are presented to help other flight test professionals determine how and when STPA can best be applied to their programs in the future.
  • Item
    Assessment of the cooperation between driver and vehicle automation: A framework
    (Elsevier, 2023) Tinga, A.M. ; Petermeijer, S.M. ; Reus, A.J.C. de ; Jansen, R.J. ; Waterschoot, B.M. van
    As long as the human driver is responsible for part(s) of the driving task during automated driving, the driver and automated driving system are sharing the driving task. Such a shared task is characterized by shared control, in which cooperation between the driver and vehicle automation is essential. However, means to holistically assess the quality of this cooperation are currently lacking. This work addresses how cooperation between driver and vehicle automation can be operationalized and assessed to gain insight into the quality of the shared driving task. Quality indicators and measurement methods are identified across seven dimensions reflective of the quality of cooperation between driver and automation. Based on previous empirical and theoretical studies a total of 34 quality indicators are identified. The methods to measure these quality indicators fall into four categories: 1) Subjective (such as questionnaires); 2) behavioral (such as reaction times, steering response); 3) neurophysiological (such as heart rate and pupil size); and 4) heuristic evaluation. The result is a first step in the development of a framework for the quantitative assessment of cooperation in the shared driving task. Yet, important knowledge gaps remain. For instance, the exact contribution of each quality indicator and their exact interrelationship are currently unclear. Moreover, all quality indicators reflect a requirement that should be met. Further research is needed to define exactly when each requirement is met. Additionally, it should be established to what degree each measurement method can validly and reliably provide insight into their quality indicator. Therefore, to ultimately ensure valid and reliable application of the framework in practice, the framework should continue to be developed and improved upon in future work.
  • Item
    Attention Guidance for Tower ATC using Augmented Reality Devices
    (IEEE, 2022) Teutsch, J. ; Bos, T.J.J. ; Apeldoorn, M.C. van ; Camara, L.
  • Item
    Braking Capabilities on Flooded Runways: Flight Test Results Obtained with a Business Jet
    (AIAA, 2017) Es, G.W.H. van
    Statistics show that the likelihood of a runway excursion during takeoff or landing is much higher on flooded runways than on dry runways. Extreme loss of tyre braking can occur during rejected takeoffs and landings on flooded runways. As a result the stopping distance increases significantly and could exceed the available runway length. Most research in the past has focused on the braking capabilities of aircraft on wet runways instead of flooded runways. Most of the knowledge of aircraft braking performance on flooded runways was gained with older aircraft designs. This knowledge is still used to determine the takeoff and landing performance of today’s modern aircraft. During the development of the European Action Plan for the Prevention of Runway Excursions it was recognised that current aircraft designs may act differently when braking on water flooded runways from aircraft tested earlier, due to new tyres and anti-skid system designs. Also the water depths during these earlier tests were often just above the wet-flooded runway threshold. Flight tests with more modern aircraft designs were therefore scheduled as part of a research project under EU’s Horizon 2020 Research and Innovation Programme. This paper summarises the flight tests conducted with a Cessna Citation II aircraft on a flooded runway. Unbraked and braked tests were conducted in a specially constructed water pond at different ground speeds. Numerous parameters were recorded during each test run including accelerations, speeds, engine performance, etc. From the test data, effective braking friction for different grounds speeds were derived, contamination drag levels were established, and insight into the hydroplaning characteristics under unbraked and braked conditions were obtained.
  • Item
    Challenges and Future Directions for Human-Drone Interaction Research: An Expert Perspective
    (Taylor & Francis, 2024) Lingam, S.N. ; Franssen, M. ; Petermeijer, S.M. ; Martens, M.
    Drones are likely to enter social spaces in the foreseeable future. Novel Human-Drone Interactions (HDI) will foster beyond typical drone-operator interaction, posing new human factors challenges. However, the specific focus areas for HDI research remain unclear. This study conducts 11 expert interviews to identify potential use cases and human factors challenges for HDI in public spaces. Initial drone use cases include emergency response and delivery scenarios, where the general public may interact as recipients and bystanders, each posing unique challenges. Uncertainty, stemming from a lack of awareness, emerges as a significant human factors concern, impacting perceived risk. Addressing this uncertainty, especially in recipients, may involve refining drone behaviour, physical appearance, and interface design. The challenges identified in this study lay the groundwork for future HDI research in public spaces.
  • Item
    CLAIRPORT - Environmental impact assessments at airport level in Clean Sky 2 TE
    (CEAS, 2021) Eenige, M.J.A. van
    Building on the first Clean Sky Programme, the Clean Sky 2 Programme aims to make a substantial contribution to the ACARE 2050 environmental goals by accelerating the introduction of new aircraft technology in the timeframe 2025-2035. Cross-positioned within this programme, the Technology Evaluator is a dedicated evaluation platform with the key role of assessing the environmental impact of technologies developed in Clean Sky 2 and their level of success towards these ACARE environmental goals. It conducts assessments at three complementary levels: aircraft, airport, and air-transport system level. This paper addresses the environmental-impact assessment at airport level for fixed-wing aircraft, as performed in the CLAIRPORT project.
  • Item
    A clustered and surrogate-based MDA use case for MDO scenarios in AGILE project
    (AIAA, 2018) Lefebre, T. ; Bartoli, N. ; Dubreuil, S. ; Panzeri, M. ; Lombardi, R. ; Lammen, W.F. ; Mengmeng, Z. ; Gent, I. van ; Ciampa, P.D.
    In this paper methodological investigations regarding an innovative Multidisciplinary Design and Optimization (MDO) approach for conceptual aircraft design are presented. These research activities are part of the ongoing EU-funded research project AGILE. The next generation of aircraft MDO processes is developed in AGILE, which targets significant reductions in aircraft development cost and time to market, leading to cheaper and greener aircraft solutions. The paper introduces the AGILE project structure and recalls the achievements of the first year of activities where a reference distributed MDO system has been formulated, deployed and applied to the design and optimization of a reference conventional aircraft configuration. Then, investigations conducted in the second year are presented, all aiming at making the complex optimization workflows easier to handle, characterized by a high degree of discipline interdependencies, multi-level processes and multi-partner collaborative engineering activities. The paper focuses on an innovative approach in which knowledge-based engineering and collaborative engineering techniques are used to handle a complex aircraft design workflow. Surrogate models replacing clusters of analysis disciplines have been developed and applied to make workflow execution more efficient. The paper details the different steps of the developed approach to set up and operate this test case, involving a team of aircraft design and surrogate modelling specialists, and taking advantage of the AGILE MDO framework. To validate the approach, different executable workflows were generated automatically and used to efficiently compare different MDO formulations. The use of surrogate models for clusters of design competences have been proved to be efficient approach not only to decrease the computational time but also to benchmark different MDO formulations on a complex optimization problem.
  • Item
  • Item
    Compressive Sensing Techniques for the Detection of Surface Waves
    ( 2024) Blaauw, K. ; Ven, H. van der
    Understanding the scattering physics of specific objects is important for their design and use. Imaging techniques may give this insight, provided that they can distinguish different scattering mechanisms. The use of compressive sensing (CS) in imaging allows to use different scattering models. In this paper, two models for surface wave (SW) scattering are described and applied to a canonical test case. We find that CS is effective in extracting the reflection of surface waves from the total radar echo. However, the standard l1-regularization of the CS optimization problem requires careful balancing of the different scattering models. It is shown that the Bayesian approach to solve the CS optimization problem does not suffer from this problem.
  • Item
    Concept Evaluation of Radical Short–Medium-Range Aircraft with Turbo-Electric Propulsion
    (MDPI, 2024) Vankan, W.J. ; Lammen, W.F. ; Scheers, E. ; Dewitte, P.A.R. ; Defoort, S.
    Ambitious targets for the coming decades have been set for further reductions in aviation greenhouse gas emissions. Hybrid electric propulsion (HEP) concepts offer potential for the mitigation of these aviation emissions. To investigate this potential in an adequate level of detail, the European research project IMOTHEP (Investigation and Maturation of Technologies for Hybrid Electric Propulsion) explores key technologies for HEP in close relation with developments of aircraft missions and configuration. This paper presents conceptual-level design investigations on radical HEP aircraft configurations for short–medium-range (SMR) missions. In particular, a blended-wing-body (BWB) configuration with a turbo-electric powertrain and distributed electric propulsion is investigated using NLR’s aircraft evaluation tool MASS. For the aircraft and powertrain design, representative top-level aircraft requirements have been defined in IMOTHEP, and the reference aircraft for the assessment of potential benefits is based on the Airbus A320neo aircraft. The models and data developed in IMOTHEP and presented in this paper show that the turbo-electric BWB configuration has potential for reduced fuel consumption in comparison to the reference aircraft. But in comparison to advanced turbofan-powered BWB configurations, which have the same benefits of the BWB airframe and advanced technology assumptions, this potential is limited. Keywords: hybrid electric propulsion; HEP; turbo-electric; blended-wing-body; energy efficiency
  • Item
  • Item
    Design and validation of a numerical high aspect ratio aeroelastic wind tunnel model (HMAE1)
    ( 2019-06) Timmermans, H.S. ; Tongeren, J.H. van ; Geurts, E.G.M. ; Marques, R.F.A. ; Correa, M.S. ; Waitz, S.
    The aircraft manufacturer Embraer, the German Aerospace Center (DLR), the Netherlands Aerospace Centre (NLR) and German–Dutch Wind Tunnels (DNW) have tested an innovative highly flexible wing within an aeroelastic wind tunnel experiment in the transonic regime. The HMAE1 project was initiated by Embraer to test its numerical predictions for wing flutter under excessive wing deformations in the transonic regime. A highly elastic fiberglass wing-body pylon nacelle wind tunnel model, which is able to deform extensively, was constructed for the experiment. The model was instrumented with a large number of pressure orifices, strain gauges, stereo pattern recognition markers and accelerometers. The wing was tested from M = 0.4 till M = 0.9 for different angles of attack and stagnation pressure. The HMAE1 model was tested in two different test campaigns in which the Mach number was increased. This paper will focus on the first test campaign of the HMAE1 project in which the windtunnel model is tested up to M = 0.7 and will describe the development of the physical numerical structural dynamic MSC Nastran model representing the manufactured windtunnel model in order to perform numerical aeroelastic analyses.
  • Item
    Design of a Tiltrotor Semi-Span Wind Tunnel Model for Whirl Flutter Investigations
    (Netherlands Aerospace Centre NLR, 2023) Hoff, S.C. van 't ; Vilsteren, J.G. van ; Cocco, A. ; Masarati, P.
  • Item
    Development of a production approach to build a titanium flaperon rib by directed energy deposition
    (Netherlands Aerospace Centre NLR, 2022) Montero - Sistiaga, M.L. ; Haagsma, R.L. ; Osinga, T. ; San Martin, U. ; Smit, M.J. de ; Nijhuis, P.