Reliable flight operations of Unmanned Aerial Vehicle (UAV) in the class above 25 kg impose strict requirements on the flight control and propulsion system. Research demonstrators however, evolve around unique aircraft configurations, while fulfilling unconventional missions. These properties increase the complexity of the on-board electromechanical devices. The latter usually rely upon Commercial off-the-shelf (COTS) components, instead of sufficiently documented, verified products. Insight into individual performance and reliability figures of these components must therefore be obtained by conducting ground-based laboratory tests. The presented test bench resembles a dynamometer for emulating aerodynamic loads on UAV servo actuators under pre-defined conditions, with the capability of monitoring and recording the relevant test parameters.
{"title":"Design of a Real-Time Test Bench for UAV Servo Actuators","authors":"Lysandros Anastasopoulos, M. Hornung","doi":"10.2514/6.2018-3735","DOIUrl":"https://doi.org/10.2514/6.2018-3735","url":null,"abstract":"Reliable flight operations of Unmanned Aerial Vehicle (UAV) in the class above 25 kg impose strict requirements on the flight control and propulsion system. Research demonstrators however, evolve around unique aircraft configurations, while fulfilling unconventional missions. These properties increase the complexity of the on-board electromechanical devices. The latter usually rely upon Commercial off-the-shelf (COTS) components, instead of sufficiently documented, verified products. Insight into individual performance and reliability figures of these components must therefore be obtained by conducting ground-based laboratory tests. The presented test bench resembles a \u0000dynamometer for emulating aerodynamic loads on UAV servo actuators under pre-defined conditions, with the capability of monitoring and recording the relevant test parameters.","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131953061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cryogenic wind-tunnel facilities face unique challenges in the calibration and operation of various measurement systems and instrumentation. Instruments that are subjected to the cryogenic conditions of the test plenum require careful design and calibration procedures to maintain instrument performance. NASA’s National Transonic Facility (NTF) and the European Transonic Windtunnel (ETW) are two cryogenic wind-tunnel facilities, each with the ability to calibrate force measurement systems (FMS) at cryogenic conditions. These facilities have different methodologies and processes for calibrating these systems. This paper discusses differences in the methodologies and processes and compares the results of two separate cryogenic calibrations of the NTF-118A force balance that were completed at both wind-tunnel facilities
{"title":"Comparative Analysis of Two Cryogenic Force Balance Calibration Systems","authors":"Kenneth G. Toro, D. Burns, P. Parker","doi":"10.2514/6.2018-4108","DOIUrl":"https://doi.org/10.2514/6.2018-4108","url":null,"abstract":"Cryogenic wind-tunnel facilities face unique challenges in the calibration and operation of various measurement systems and instrumentation. Instruments that are subjected to the cryogenic conditions of the test plenum require careful design and calibration procedures to maintain instrument performance. NASA’s National Transonic Facility (NTF) and the European Transonic Windtunnel (ETW) are two cryogenic wind-tunnel facilities, each with the ability to calibrate force measurement systems (FMS) at cryogenic conditions. These facilities have different methodologies and processes for calibrating these systems. This paper discusses differences in the methodologies and processes and compares the results of two separate cryogenic calibrations of the NTF-118A force balance that were completed at both wind-tunnel facilities","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130305112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Real-Time, High-Bandwidth Measurement of Large Amplitude Velocity and Temperature Fluctuations Using Constant Voltage Anemometry","authors":"A. Mangalam","doi":"10.2514/6.2018-2991","DOIUrl":"https://doi.org/10.2514/6.2018-2991","url":null,"abstract":"","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130388582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Beck, C. Klein, U. Henne, M. Merienne, Y. Le Sant, P. Molton
The performance of two different PSP used at DLR and ONERA is compared by carrying out bench mark testing using the oft-studied configuration of an oscillating shock wave (up to 100 Hz) on a bump in the Mach 1.4 flow of the ONERA S8Ch wind tunnel. The shock is made to oscillate by rotating a cam with elliptical cross section, placed at a further downstream position, at frequencies of 15, 30 and 50 Hz. Both paint types are well known and much has been published on their use: the ONERA PSP is a Ruthenium complex Ru(dpp)_3Cl_2 placed as a thin layer on an anodized aluminum substrate, while the DLR PSP is a Platinum complex PtTFPP on a base coating containing TiO_2 particles. S8 run conditions were held constant, and separate test run series were carried out with each paint. Instationary calibration was also carried out using a special test rig. Fourier analyses of the PSP results in S8 enabled a semi-quantitative comparison of the time response of both paints. This is the first published attempt (to the authors’ knowledge) of carrying out a side-by-side comparison of the characteristics of these two paints on such a flow configuration in a wind tunnel. Particular emphasis is placed on their handling properties and, above all, their time responses.
{"title":"Measurement of an Oscillating Shock Wave in a Transonic Flow Using Two Different Pressure Sensitive Paints* (*Ru-based on anodized aluminum vs. Pt-based with screen layer)","authors":"W. Beck, C. Klein, U. Henne, M. Merienne, Y. Le Sant, P. Molton","doi":"10.2514/6.2018-3316","DOIUrl":"https://doi.org/10.2514/6.2018-3316","url":null,"abstract":"The performance of two different PSP used at DLR and ONERA is compared by carrying out bench mark testing using the oft-studied configuration of an oscillating shock wave (up to 100 Hz) on a bump in the Mach 1.4 flow of the ONERA S8Ch wind tunnel. The shock is made to oscillate by rotating a cam with elliptical cross section, placed at a further downstream position, at frequencies of 15, 30 and 50 Hz. Both paint types are well known and much has been published on their use: the ONERA PSP is a Ruthenium complex Ru(dpp)_3Cl_2 placed as a thin layer on an anodized aluminum substrate, while the DLR PSP is a Platinum complex PtTFPP on a base coating containing TiO_2 particles. S8 run conditions were held constant, and separate test run series were carried out with each paint. Instationary calibration was also carried out using a special test rig. Fourier analyses of the PSP results in S8 enabled a semi-quantitative comparison of the time response of both paints. This is the first published attempt (to the authors’ knowledge) of carrying out a side-by-side comparison of the characteristics of these two paints on such a flow configuration in a wind tunnel. Particular emphasis is placed on their handling properties and, above all, their time responses.","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126740116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A modified and extended version of a convergence test for wind tunnel strain–gage balance load iterations was implemented. The test uses an upper bound of the Lipschitz constant to assess convergence characteristics of balance load predictions if the Iterative Method is applied. Convergence is expected within the use envelope of the balance whenever this upper bound is less than the threshold of one. It is explained in great detail how the convergence test can be applied to the two load iteration equation types that are currently being used in the aerospace testing community. In addition, the application of the test to balances with bi–directional output characteristics is discussed. It is also shown how numerical differentiation can be used to obtain partial derivatives that are needed for the calculation of the Lipschitz constant. Finally, machine calibration data of NASA’s MC60E six–component force balance is selected to demonstrate both implementation and use of the convergence test.
{"title":"Implementation and Use of a Convergence Test for Iterative Wind Tunnel Balance Load Predictions","authors":"N. Ulbrich","doi":"10.2514/6.2018-4109","DOIUrl":"https://doi.org/10.2514/6.2018-4109","url":null,"abstract":"A modified and extended version of a convergence test for wind tunnel strain–gage balance load iterations was implemented. The test uses an upper bound of the Lipschitz constant to assess convergence characteristics of balance load predictions if the Iterative Method is applied. Convergence is expected within the use envelope of the balance whenever this upper bound is less than the threshold of one. It is explained in great detail how the convergence test can be applied to the two load iteration equation types that are currently being used in the aerospace testing community. In addition, the application of the test to balances with bi–directional output characteristics is discussed. It is also shown how numerical differentiation can be used to obtain partial derivatives that are needed for the calculation of the Lipschitz constant. Finally, machine calibration data of NASA’s MC60E six–component force balance is selected to demonstrate both implementation and use of the convergence test.","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125907460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Preliminary Experimental Investigation on MHD Power Generation by Using Arc Heater","authors":"D. Ou","doi":"10.2514/6.2018-3736","DOIUrl":"https://doi.org/10.2514/6.2018-3736","url":null,"abstract":"","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121464177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Winter, R. Green, C. Borchetta, E. Josyula, J. Hayes, J. Jewell, B. Hagen
OF THESIS EXPERIMENTAL INVESTIGATION OF IMAGE DISTORTION IN A MACH 6 HYPERSONIC FLOW The image distortion that is inherently present when imaging through a flow field at hypersonic speeds was investigated. The original problem involves observation of the outside world from the inside an aircraft moving at hypersonic speeds. For this work, a Mach 6 hypersonic wind tunnel at Wright Patterson Air Force Base (WPAFB) was used and optical patterns were imaged with and without flow field characteristics. Two test campaigns were scheduled to conduct experiments that would provide answers to the proposed problem of the effect on observable aberrations through flow fields. During the first test campaign, October 2017, optical patterns were laser etched on anodized aluminum inserts that would couple to a 15°-degree wedge probe that had been operated with the Mach 6 tunnel previously. During this test phase, lessons learned were extremely acknowledged for preparing for the second campaign in February-March 2019. A primary effect observed was due to tunnel vibrations that created apparent optical distortion by “smearing” the optical patterns over the acquisition time of the camera. During the second test campaign there were 2 primary test models that would be mounted in the tunnel for optical analysis. Newly manufactured steel plates were coupled to the already investigated 15°-degree wedge probe for verification of what was observed previously. Also, a 7° half angle cone was manufactured as a replica of a cone that was already in operation at WPAFB. Characterization of optical distortion was done by using a quantity known as a Strehl Ratio. The Strehl Ratio is defined as the ratio of the peak intensity of a point source from an aberrated image, which has been affected due to distortion, to the corresponding point source from a diffraction limited system. Line Distribution Functions (LDFs) were identified to expand the definition from a ratio of maximums to a ratio of the shapes of the line widths. Measured vibrational influences were extracted in both the axial and vertical directions of flow to account for any artificial distortion mechanisms. These lines in both directions created our optical patterns simultaneously giving information of vibrational influences in either direction as well as the measured distortion over the test targets. Lastly, there was an attempt to relate the experimental findings to real world applications. Considerations from the first test campaign using the wedge probe are presented for this using what is known from the General Image Quality Equation (GIQE). This was developed as an analytical solution for determining image quality parameters within the National Imagery Interpretability Rating Scale (NIIRS).
{"title":"Experimental Investigation of Image Distortion in a Mach 6 Hypersonic Flow","authors":"M. Winter, R. Green, C. Borchetta, E. Josyula, J. Hayes, J. Jewell, B. Hagen","doi":"10.2514/6.2018-4197","DOIUrl":"https://doi.org/10.2514/6.2018-4197","url":null,"abstract":"OF THESIS EXPERIMENTAL INVESTIGATION OF IMAGE DISTORTION IN A MACH 6 HYPERSONIC FLOW The image distortion that is inherently present when imaging through a flow field at hypersonic speeds was investigated. The original problem involves observation of the outside world from the inside an aircraft moving at hypersonic speeds. For this work, a Mach 6 hypersonic wind tunnel at Wright Patterson Air Force Base (WPAFB) was used and optical patterns were imaged with and without flow field characteristics. Two test campaigns were scheduled to conduct experiments that would provide answers to the proposed problem of the effect on observable aberrations through flow fields. During the first test campaign, October 2017, optical patterns were laser etched on anodized aluminum inserts that would couple to a 15°-degree wedge probe that had been operated with the Mach 6 tunnel previously. During this test phase, lessons learned were extremely acknowledged for preparing for the second campaign in February-March 2019. A primary effect observed was due to tunnel vibrations that created apparent optical distortion by “smearing” the optical patterns over the acquisition time of the camera. During the second test campaign there were 2 primary test models that would be mounted in the tunnel for optical analysis. Newly manufactured steel plates were coupled to the already investigated 15°-degree wedge probe for verification of what was observed previously. Also, a 7° half angle cone was manufactured as a replica of a cone that was already in operation at WPAFB. Characterization of optical distortion was done by using a quantity known as a Strehl Ratio. The Strehl Ratio is defined as the ratio of the peak intensity of a point source from an aberrated image, which has been affected due to distortion, to the corresponding point source from a diffraction limited system. Line Distribution Functions (LDFs) were identified to expand the definition from a ratio of maximums to a ratio of the shapes of the line widths. Measured vibrational influences were extracted in both the axial and vertical directions of flow to account for any artificial distortion mechanisms. These lines in both directions created our optical patterns simultaneously giving information of vibrational influences in either direction as well as the measured distortion over the test targets. Lastly, there was an attempt to relate the experimental findings to real world applications. Considerations from the first test campaign using the wedge probe are presented for this using what is known from the General Image Quality Equation (GIQE). This was developed as an analytical solution for determining image quality parameters within the National Imagery Interpretability Rating Scale (NIIRS).","PeriodicalId":373890,"journal":{"name":"2018 Aerodynamic Measurement Technology and Ground Testing Conference","volume":"391 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133157507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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