Articles de revues : « Experimental flight »

1

Gururajan, Srikanth, et Ye Bai. « Autonomous “Figure-8” Flights of a Quadcopter : Experimental Datasets ». Data 4, n^o 1 (9 mars 2019) : 39. http://dx.doi.org/10.3390/data4010039.

Texte intégral

Résumé :

This article describes the data acquired from multiple flights of a custom-built quadcopter. The Quadcopter was programmed to fly a pre-defined “Figure-8” flight path, at a constant altitude. The data set includes flights with a varying number of waypoints (10 and 15 waypoints in each lobe of the “Figure-8”) and at two different velocities (1.5 and 2.5 m/s). The data also contains information on the output of the flight controller in terms of the Pulse Width Modulation (PWM) signals to each of the four Electronic Speed Controllers (ESC) driving the motors, the recorded outputs of the Inertial Measurement Unit (linear accelerations ax, ay, az and angular velocities p, q, r), GPS data (Latitude, Longitude, altitude, Horizontal Dilution of Precision (HDOP) and Vertical Dilution of Precision (VDOP). The data are included as Supplemental Material.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Caprace, Denis-Gabriel, Camille Gontier, Mohammad Iranmanesh, Mehdi Scoubeau et Vladimir Pletser. « Experimental Characterization of Weightlessness During Glider Parabolic Flights ». Microgravity Science and Technology 32, n^o 6 (10 octobre 2020) : 1121–32. http://dx.doi.org/10.1007/s12217-020-09836-6.

Texte intégral

Résumé :

Abstract Access to earthbound weightlessness is critical to many branches of applied sciences. Besides, several space systems require microgravity testing before their launch. Existing solutions (drop towers, parabolic flights, sounding rockets) offer variable durations and qualities of microgravity environment, but their cost and lead times make them unpractical for small actors such as universities or start-up companies. This leads to a growing interest for alternative microgravity platforms. Here, we study the use of gliders to perform parabolic flights at a lower cost, and we propose a systematic quantification of glider’s 0-g flight capabilities. Results of our flight test campaign show that gliders offer up to 5.5s of weightlessness, with excursions below 0.1g, and a satisfactory level of repeatability. Besides, the recordings do not suffer from the increased level of vibrations generated by piston engines, typical of light-aircraft-based alternatives. Operational considerations associated with glider parabolic flights are also discussed. Finally, we conclude that a microgravity platform based on gliders would be suitable especially for compact experiments and equipment in order to support accelerated design and development, or to produce preliminary experimental results.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Beh, Helen C., et Peter McLaughlin. « Effect of Long Flights on the Cognitive Performance of Air Crew ». Perceptual and Motor Skills 84, n^o 1 (février 1997) : 319–22. http://dx.doi.org/10.2466/pms.1997.84.1.319.

Texte intégral

Résumé :

The cognitive performance of groups of subjects was tested after flights lasting between 7.5–9.5 hours to the north, east and west of Sydney ( ns = 10, 12, and 12) and compared with the performance of a ground-based control group ( n = 12). Analysis showed an impairment in performance of the flight groups following the flights. The analysis suggests that part of the performance change following transzonal flights may result from stress induced during the flight rather than adjustment to new time zones.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Pang, Liping, Pei Li, Xiaodong Cao et Xiaoru Wanyan. « Experimental study of the changes in thermal expectation during simulated flights in a civil aircraft cabin mockup ». Indoor and Built Environment 29, n^o 9 (18 mai 2020) : 1277–88. http://dx.doi.org/10.1177/1420326x20925113.

Texte intégral

Résumé :

Aircraft cabin thermal environment is a key issue on flight selection by passengers, especially for long-haul flights. Currently, there have been some studies on the passengers’ thermal comfort in civil aircraft cabins. However, information is still limited on the changes in passenger thermal expectation with flight time. In this study, an aircraft cabin mockup was built, and three experiments involving human subjects were carried out in order to study the in-flight thermal environment in winter, summer and autumn, respectively. The cabin temperatures during the experiments were controlled according to the thermal neutral temperature model derived from our previous study on actual flights. The thermal neutral temperature model was checked by experimental results. The changes in thermal expectation were investigated based on physical measurement and questionnaire survey. In each experiment, the changes in the mean thermal sensation votes of passengers were less than 1, while the cabin temperature increased by 2.8°C, 1.8°C and 2°C from the beginning to the end during the three experiments, respectively. With the increase in the simulated flight time, passengers gradually expected a slightly higher cabin temperature. This trend would become very obvious when the simulated flight time was longer than 2 h.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Shao, Quan, Mengxue Shao, Yunpeng Bin, Pei Zhu et Yan Zhou. « Flight Recovery Method of Regional Multiairport Based on Risk Control Model ». Mathematical Problems in Engineering 2020 (29 avril 2020) : 1–18. http://dx.doi.org/10.1155/2020/7105381.

Texte intégral

Résumé :

In the regional multiairport system, the contradiction between the limited operating resources and the large flight flow is serious, and the flight delays can easily lead to the occurrence of unsafe events. This paper investigates the abnormal flight recovery method in regional multiairport system based on risk control. The focus is to reschedule arrival-departure flights in real time with minimized delay time and risk probability. In this study, the risk about terminal area control and scene operation was considered in the analysis of the risk control model (RCM), which includes six key risk points: airspace control, flight conflict, ground service, apron support, ground control, and taxiing conflict. The mathematical model on flight recovery was constructed to solve minimized delay time and risk probability with MSINS (multistart algorithm with intelligent neighborhood selection). The data of a typical regional multiairport system in China were selected for experimental verification in order to compare the RCM with the traditional recovery model (TRM). The experimental results show that first, there are some hidden dangers in the traditional recovery methods of flight delay. Flight conflict and apron support are the risk points that need to be controlled most in the multiairport system. Secondly, for the effective solution with the shortest delay time, the RCM can reduce the overall operation risk of the system, but the flight delay time is a little longer. For the effective solution with the lowest risk probability, RCM can reduce the risk of system operation and the delay time of flights at the same time. Therefore, RCM can improve the security level of the system during abnormal flight recovery and ensure or even improve the recovery efficiency.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Muravyov, I. S. « Method of training pilots of the latest-generation aircraft to interact with crews of other aircraft ». Civil Aviation High Technologies 26, n^o 5 (30 octobre 2023) : 42–52. http://dx.doi.org/10.26467/2079-0619-2023-26-5-42-52.

Texte intégral

Résumé :

Training pilots of latest-generation aircraft to interact with other crews in flight is complicated by the high level of cockpit automation and information overload of crews, on the one hand, and by the responsibility of pilots for decisions made regarding air traffic, on the other hand. Since the unified methodology for training pilots to interact with other crews in the same airspace is not available, the development of qualitative training is required. To address this issue, a method, based on a preliminary calculation of the amount of information which is necessary to process by a pilot when training depending on the type of this information for the efficient formation of a conceptual model of air traffic in flight, has been developed. The method of forming a conceptual model of air traffic is based on the application of a mathematical model of “random walk with absorption”. The method consists of three phases. In the first flight phase, a pilot should operate a training flight en route. In the first flight of the second training phase, a trainee evaluates the tendency for the approach (separation) of the assessed aircraft to the trainee aircraft. In the second flight of the second phase, the assessed aircraft position is determined by the crew position and altitude reports, in the third flight – by the crew position, heading and altitude reports. In the third training phase, when operating three flights primarily en route, a trainee is supposed to evaluate the air situation according to all the parameters reported by crews operating in the same airspace. After flights of the second and third training phases, the pilot is meant to analyze and evaluate the air situation while operating a flight comprehensively by the number of aircraft in the flight area, their position and the sequence of their motion. The experimental results made it possible to determine that participants in the experimental group were 24% more efficient in evaluating the air situation and interacting with other crews in flight in the same flight area compared to the control group pilots. Processing of the experimental results showed that when employing the proposed training method, the reliability of the latest-generation aircraft crew interaction at the automatic piloting mode was statistically significantly increased.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Otsuka, Yasutami, Akihiko Onozawa, Azusa Kikukawa et Yoshinori Miyamoto. « Effects of Flight Workload on Urinary Catecholamine Responses in Experienced Military Pilots ». Perceptual and Motor Skills 105, n^o 2 (octobre 2007) : 563–71. http://dx.doi.org/10.2466/pms.105.2.563-571.

Texte intégral

Résumé :

This study investigated the flight responses induced by strenuous aerobatic demonstration flight and an air-to-air combat maneuvering flight in experienced pilots. Subjects were 54 military male pilots on a volunteer basis: 8 T-4 pilots ( M = 35.8 yr., SD = 4.9), 15 F-4 pilots ( M = 32.6 yr., SD = 5.1), 13 F-15 pilots ( M = 33.8 yr., SD = 1.0), and 18 F-2 pilots ( M = 33.7 yr., SD = 3.9). Samples of urine were collected approximately 30 min. before and 20 min. after the flights. The postflight adrenaline in all pilots was significantly higher than at preflight, while a significant increase in noradrenaline at postflight was not observed. The post-/preflight ratio of adrenaline in all pilots was relatively similar and high. These findings might be regarded as a result of autonomic nervous system response to the flight workload of military pilots. Especially is increment in sympathetic activity considered to play an important part in psychological adaptation to flight.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Hwang, Jinsoo, Seong Ok Lyu et Sun-Bai Cho. « In-Flight Casinos, Is It Really a Nonsensical Idea ? An Exploratory Approach Using Different Choice Experiments ». Sustainability 11, n^o 11 (29 mai 2019) : 3038. http://dx.doi.org/10.3390/su11113038.

Texte intégral

Résumé :

Most airlines make various efforts to enhance their customers’ levels of in-flight satisfaction while offering alternative services and entertainment. As an innovative service item, some international airlines plan in-flight casino facilities to relieve their customers’ boredom and fatigue emanating from tedious long flights. Using a study sample of casino visitors in Korea, we intend to better understand how potential airline passengers show their willingness to pay for the hypothetical in-flight casino services. We also employ multiple choice experimental techniques to examine preference heterogeneity embedded in the sampled population. Based on study results, several management strategies are discussed for offering tailored in-flight entertainment services to targeted market segments.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Qin, Kun, Qixin Wang, Binbin Lu, Huabo Sun et Ping Shu. « Flight Anomaly Detection via a Deep Hybrid Model ». Aerospace 9, n^o 6 (19 juin 2022) : 329. http://dx.doi.org/10.3390/aerospace9060329.

Texte intégral

Résumé :

In the civil aviation industry, security risk management has shifted from post-accident investigations and analyses to pre-accident warnings in an attempt to reduce flight risks by identifying currently untracked flight events and their trends and effectively preventing risks before they occur. The use of flight monitoring data for flight anomaly detection is effective in discovering unknown and potential flight incidents. In this paper, we propose a time-feature attention mechanism and construct a deep hybrid model for flight anomaly detection. The hybrid model combines a time-feature attention-based convolutional autoencoder with the HDBSCAN clustering algorithm, where the autoencoder is constructed and trained to extract flight features while the HDBSCAN works as an anomaly detector. Quick access record (QAR) flight data containing information of aircraft landing at Kunming Changshui International and Chengdu Shuangliu International airports are used as the experimental data, and the results show that (1) the time-feature-based convolutional autoencoder proposed in this paper can better extract the flight features and further discover the different landing patterns; (2) in the representation space of the flights, anomalous flight objects are better separated from normal objects to provide a quality database for subsequent anomaly detection; and (3) the discovered flight patterns are consistent with those at the airports, resulting in anomalies that could be interpreted with the corresponding pattern. Moreover, several examples of anomalous flights at each airport are presented to analyze the characteristics of anomalies.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Califar, Brandon, Agata Zupanska, Jordan A. Callaham, Matthew T. Bamsey, Thomas Graham, Anna-Lisa Paul et Robert J. Ferl. « Shared Metabolic Remodeling Processes Characterize the Transcriptome of Arabidopsis thaliana within Various Suborbital Flight Environments ». Gravitational and Space Research 9, n^o 1 (1 janvier 2021) : 13–29. http://dx.doi.org/10.2478/gsr-2021-0002.

Texte intégral

Résumé :

Abstract The increasing availability of flights on suborbital rockets creates new avenues for the study of spaceflight effects on biological systems, particularly of the transitions between hypergravity and microgravity. This paper presents an initial comparison of the responses of Arabidopsis thaliana to suborbital and atmospheric parabolic flights as an important step toward characterizing these emerging suborbital platforms and their effects on biology. Transcriptomic profiling of the response of the Arabidopsis ecotype Wassilewskija (WS) to the aggregate suborbital spaceflight experiences in Blue Origin New Shepard and Virgin Galactic SpaceShipTwo revealed that the transcriptomic load induced by flight differed between the two flights, yet was biologically related to traditional parabolic flight responses. The sku5 skewing mutant and 14-3-3κ:GFP regulatory protein overexpression lines, flown in the Blue Origin and parabolic flights, respectively, each showed altered intra-platform responses compared to WS. An additional parabolic flight using the F-104 Starfighter showed that the response of 14-3-3κ:GFP to flight was modulated in a similar manner to the WS line. Despite the differing genotypes, experimental workflows, flight profiles, and platforms, differential gene expression linked to remodeling of central metabolic processes was commonly observed in the flight responses. However, the timing and directionality of differentially expressed genes involved in the conserved processes differed among the platforms. The processes included carbon and nitrogen metabolism, branched-chain amino acid degradation, and hypoxic responses. The data presented herein highlight the potential for various suborbital platforms to contribute insights into biological responses to spaceflight, and further suggest that in-flight fixation during suborbital experiments will enhance insights into responses during each phase of flight.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Charles Catania, A. « Discussion : The Flight From Experimental Analysis ». European Journal of Behavior Analysis 13, n^o 2 (décembre 2012) : 165–76. http://dx.doi.org/10.1080/15021149.2012.11434416.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

12

VIDELER, J. J., G. VOSSEBELT, M. GNODDE et A. GROENEWEGEN. « Indoor Flight Experiments with Trained Kestrels : I. Flight Strategies in Still Air with and Without Added Weight ». Journal of Experimental Biology 134, n^o 1 (1 janvier 1988) : 173–83. http://dx.doi.org/10.1242/jeb.134.1.173.

Texte intégral

Résumé :

Two kestrels, a male and a female, were trained to fly over 50 and 125 m in a windless corridor. Both distances were flown with or without dead weights attached to the feet during 13 flight sessions for each bird. Added weight was either 0.3 N (31 g lead) or 0.6 N (61 g). Each session was devoted to one distance and one flight weight category. Flight duration was automatically recorded at the landing points and at four positions along the track. Gliding bouts were hand-clocked and flight altitudes were estimated with the aid of sidewall markings. An analysis was made of 1226 flights by the female over a total of 100 km, and 1017 flights by the male over 84.6 km. Different flight strategies were observed under the different experimental situations, and were compared with model predictions for optimal speeds. In the unloaded situations the birds flew at velocities close to the maximum range speed. Under load, speeds were lower and close to the predicted speeds for minimum power when 0.6 N was added to the weight.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Elhesasy, Mohamed, Rashed Khader, Tarek N. Dief, Mohamed M. Kamra, Mohamed Okasha et Saeed K. Alnuaimi. « Experimental Identification of the Translational Dynamics of a Novel Two-Layer Octocopter ». Drones 8, n^o 7 (26 juin 2024) : 286. http://dx.doi.org/10.3390/drones8070286.

Texte intégral

Résumé :

This paper proposes a systematic approach for identifying the translational dynamics of a novel two-layer octocopter. Initially, we derive the non-linear theoretical dynamic model of the conventional octocopter using the Newton–Euler formulation, aimed at obtaining a simplified model suitable for tuning PID gains necessary for controller implementation. Following this, a controller is designed and tested in the Matlab/Simulink environment to ensure stable flight performance of the octocopter. Subsequently, the novel octocopter prototype is developed, fabricated, and assembled, followed by a series of outdoor flight tests conducted under various environmental conditions to collect data representing the flight characteristics of the two-layer vehicle in different scenarios. Based on the data recorded during flights, we identify the transfer functions of the translational dynamics of the modified vehicle using the prediction error method (PEM). The empirical model is then validated through different flight tests. The results presented in this study exhibit a high level of agreement and demonstrate the efficacy of the proposed approach to predict the octocopter’s position based only on motor inputs and initial states of the system. Despite the inherent non-linearity, significant aerodynamic interactions, and strongly coupled nature of the system, our findings highlight the robustness and reliability of the proposed approach, which can be used to identify the model of any type of multi-rotor or fixed-wing UAV, specifically when you have a challenging design.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Feng, Xiao Rong, Xing Jie Feng et Dong Liu. « The Application of Ant Colony Optimization Algorithm in the Flight Landing Scheduling Problem ». Applied Mechanics and Materials 411-414 (septembre 2013) : 2698–703. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.2698.

Texte intégral

Résumé :

Flights landing scheduling problem is an NP-hard problem, the article presents an Ant colony optimization algorithm based on dynamic calculation of the heuristic information to solve a single runway flights landing scheduling problem. The algorithm has better global search ability and relatively fast convergence rate. The experimental results show that compared with traditional first come first serve, genetic algorithm and particle swarm algorithm, this method can quickly give the better flight approach and landing order to help controllers make efficient aircraft scheduling policy and reduce flight delays. Keywords:Heuristic Information entropy Ant colony optimization Global search

Styles APA, Harvard, Vancouver, ISO, etc.

15

Kulba, P., V. Fedenko, O. Cherednikov, V. Chupryna et O. Pankul. « TAKING INTO ACCOUNT THE REQUIREMENTS OF EUROPEAN CRITERIA FOR CERTIFICATION OF AIRWORTHINESS OF AIRCRAFT IN TECHNIQUES FOR TESTING THE FLIGHT-TECHNICAL CHARACTERISTICS OF HELICOPTERS ». Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, n^o 10 (30 décembre 2021) : 108–16. http://dx.doi.org/10.37701/dndivsovt.10.2021.12.

Texte intégral

Résumé :

The article considers the problem of improving the methods of testing to determine the flight characteristics of helicopters, taking into account the requirements of European criteria for certification of airworthiness of military aircraft. To ensure interoperability with NATO standards, new standard methods for obtaining and evaluating the flight performance of helicopters have been developed. On the example of determining fuel consumption in assessing the range and duration of the flight considered the basic principles of development of advanced standard techniques. The test methods are based on the use of experimental planning theory using first- and second-order plans. Based on the mathematical theory of experimental planning, regression models of flight technical characteristics of helicopters are compiled and all coefficients of these models are determined. On the basis of the received regression models flight technical characteristics in all range of the used parameters of flights of helicopters of various categories, types and models are calculated. For example, the results of nomogram calculations for determining the kilometer fuel consumption of a helicopter while flying at different speeds in different altitude and climatic conditions are presented. The use of modeling provides increased reliability and accuracy in determining the flight characteristics of helicopters and significantly reduces the cost of testing. Developed advanced techniques, which are adapted to European standards, allow to cover all customer requirements, ie to determine and assess the flight characteristics of helicopters according to the requirements of both national and foreign customers.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Ortiz, Julio, Atsushi Serino, Toshinari Hasegawa, Takahito Onoguchi, Hiroki Maemukai, Takeshi Miyazaki et Hiroki Sugiura. « Experimental and Computational Study of Archery Arrows Fletched with Straight Vanes ». Proceedings 49, n^o 1 (15 juin 2020) : 56. http://dx.doi.org/10.3390/proceedings2020049056.

Texte intégral

Résumé :

The aerodynamic characteristics of archery arrows fletched with two types of straight vanes, for which the area is different, were studied. The arrows’ pitching moment (CM), lift (CL) and drag (CD) coefficients were measured in the 60 × 60 cm Magnetic Suspension and Balance System (MSBS) from JAXA. At a Reynolds number of Re = 1.2 × 104, the values of CD were 1.56 and 2.05 for the short and large vanes, respectively. In a second experimental procedure, the arrows’ deceleration in free flight was measured by inserting an acceleration sensor inside their shafts. For shots with an initial velocity of around 56.4 ms−1, a velocity decay of around 8% was measured. A turbulent–laminar boundary layer transition during free flight was found for shots with an average Re = 1.8 × 104. Lastly, through numerical computations, the area difference of the two vanes was analyzed to verify the importance of CM and CL during the arrows’ flights.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Qu, Jingyi, Shixing Wu et Jinjie Zhang. « Flight Delay Propagation Prediction Based on Deep Learning ». Mathematics 11, n^o 3 (17 janvier 2023) : 494. http://dx.doi.org/10.3390/math11030494.

Texte intégral

Résumé :

The current flight delay not only affects the normal operation of the current flight, but also spreads to the downstream flights through the flights schedule, resulting in a wide range of flight delays. The analysis and prediction of flight delay propagation in advance can help civil aviation departments control the flight delay rate and reduce the economic loss caused by flight delays. Due to the small number of data samples that can constitute flight chains, it is difficult to construct flight chain data. In recent years, the analysis of the flight delay propagation problem is generally based on traditional machine learning methods with a small sample size. After obtaining a large amount of raw data from the China Air Traffic Management Bureau, we have constructed 36,287 pieces of three-level flight chain data. Based on these data, we tried to use a deep learning method to analyze and forecast flight delays. In the field of deep learning, there are CNN models and RNN models that deal with classification problems well. Based on these two classes of models, we modify and innovate the study of the problem of flight delay propagation and prediction. Firstly, the CNN-based CondenseNet algorithm is used to predict the delay level of the three-level flight chain data. Based on this, the CondenseNet network is improved by inserting CBAM modules and named CBAM-CondenseNet. The experimental results show that the improved algorithm can effectively improve the network performance, and the prediction accuracy can reach 89.8%. Compared with the traditional machine learning method, the average prediction accuracy increased by 8.7 percentage points. On the basis of the CNN model, we also considered the superiority of the LSTM (Long Short-Term Memory network) considering the processing time sequence information, and then constructed the CNN-MLSTM network and injected the SimAM module to enhance the attention of flight chain data. In the experiment of flight delay propagation prediction, the accuracy rate is 91.36%, which is a significant improvement compared to using the CNN or LSTM alone.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Fruncillo, Felice, Luigi Federico, Marco Cicala et Roberto Citarella. « Development and Validation of an Aeropropulsive and Aeroacoustic Simulation Model of a Quadcopter Drone ». Drones 6, n^o 6 (9 juin 2022) : 143. http://dx.doi.org/10.3390/drones6060143.

Texte intégral

Résumé :

In the present work a dynamic simulation model for a quadcopter drone is developed and validated through experimental flight data. The aerodynamics of the rotors is modeled with the blade element theory combined with the Peters and He dynamic wake model, using an appropriate number of states. The aerodynamic forces and moments thus calculated feed the dynamic equations of a drone and an aeroacoustics model, to obtain an estimate of the noise generated during the flight. Loading and thickness noise are calculated as a time domain solution of the wave equation (Farassat 1A formulation), with mobile sources in stagnant flow. The results of numerical simulations are compared with experimental data recorded during flights performed at the Aerospace Italian Research Center (CIRA), both for the flight dynamics and the aeroacoustics models. To customize the model to the drone used, a laser scanner is used to obtain the geometric characteristics of the blades and the XFOIL program is used to calculate the blade profile aerodynamic coefficients.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Motyl, K., M. Magier, J. Borkowski et B. Zygmunt. « Theoretical and experimental research of anti-tank kinetic penetrator ballistics ». Bulletin of the Polish Academy of Sciences Technical Sciences 65, n^o 3 (27 juin 2017) : 399–404. http://dx.doi.org/10.1515/bpasts-2017-0045.

Texte intégral

Résumé :

Abstract A mathematical-physical model of the hypersonic anti-tank kinetic subcalibre projectile for 120 mm munition was built. Computer simulations of the projectile flight were performed for any angle of shooting, from 0° to 90°. Trajectories of projectile flights were determined considering all angles of shooting. Theoretical calculations were verified by experimental measurement of the projectile velocity in time while shooting on a test range. Some conclusions with regard to safety during hypersonic projectile shooting on the test range were formulated.

Styles APA, Harvard, Vancouver, ISO, etc.

20

YI, WENJUN, DONGYANG SUN, JUNJIE TAN et DANDAN YUAN. « EXPERIMENTAL RESEARCH ON AEROELASTICITY OF A LARGE LENGTH TO DIAMETER RATIO PROJECTILE ». International Journal of Modern Physics : Conference Series 19 (janvier 2012) : 270–75. http://dx.doi.org/10.1142/s2010194512008859.

Texte intégral

Résumé :

In order to investigate the aeroelastic influences on the aerodynamic performance and flight stability of a large length to diameter ratio projectile, free-flight experiments on both the flexible and rigid projectile model are performed in our ballistic range. Many groups of shadowgraphs for these two kinds of projectiles during flight tests were taken and one of those typical results is shown. The projectile flight velocity, angle of attack and precession are obtained after the data procession. Moreover, the aerodynamic force and moment coefficients of two kinds of projectiles are presented, their aerodynamic performances and flight stability are compared and analyzed. Our results show that the flexible projectile has larger drag coefficient than the rigid. After the deformation, its lift to drag ratio decreases and its rotation moment increases obviously. The elastic deformation of the flexible projectile has remarkable influence on its flight stability which can induce the flight instability.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Araujo, João Otávio, João Valente, Lammert Kooistra, Sandra Munniks et Ruud J. B. Peters. « Experimental Flight Patterns Evaluation for a UAV-Based Air Pollutant Sensor ». Micromachines 11, n^o 8 (11 août 2020) : 768. http://dx.doi.org/10.3390/mi11080768.

Texte intégral

Résumé :

The use of drones in combination with remote sensors have displayed increasing interest over the last years due to its potential to automate monitoring processes. In this study, a novel approach of a small flying e-nose is proposed by assembling a set of AlphaSense electrochemical-sensors to a DJI Matrix 100 unmanned aerial vehicle (UAV). The system was tested on an outdoor field with a source of NO2. Field tests were conducted in a 100 m2 area on two dates with different wind speed levels varying from low (0.0–2.9m/s) to high (2.1–5.3m/s), two flight patterns zigzag and spiral and at three altitudes (3, 6 and 9 m). The objective of this study is to evaluate the sensors responsiveness and performance when subject to distinct flying conditions. A Wilcoxon rank-sum test showed significant difference between flight patterns only under High Wind conditions, with Spiral flights being slightly superior than Zigzag. With the aim of contributing to other studies in the same field, the data used in this analysis will be shared with the scientific community.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Daidzic, Nihad E. « MATHEMATICAL MODEL OF HOT-AIR BALLOON STEADY-STATE VERTICAL FLIGHT PERFORMANCE ». Aviation 25, n^o 3 (7 octobre 2021) : 149–58. http://dx.doi.org/10.3846/aviation.2021.15330.

Texte intégral

Résumé :

Vertical flight performance of Lighter-than-Air free hot-air balloons is derived and discussed. Novel mathematical model using lumped-parameters has been used to model balloon flight dynamics and steady-state performance in particular. Thermal model was not treated as the super-heat is under the control of aeronauts/pilots. Buoyancy or gross lift, net or effective lift, specific lift, and excess specific lift were derived for a general single envelope balloon and can be applied to hot-air, gas and hybrid balloons. Rate-of-climb, absolute ceiling, rate-of-descent, and the maximum rate-of-descent or the uncontrolled terminal descent have all been modeled and sample computations performed for AX8 or AX9 FAI-class hot-air balloons. Lifting index or the specific net/effective lift have been computed treating ambient and hot air as ideal gases at various pressure altitudes and representative envelope temperatures. Drag coefficient in upward and downward vertical flights have been chosen based on best available data. Experimental scale and full-scale flight tests are suggested for more accurate estimates of external aerodynamics in vertical balloon flights. CFD computations of coupled inner- and external-flows are also recommended in future efforts. Knowledge of free balloon’s vertical performance is essential in flight planning and operational safety of flight.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Sakurai, Hiroki, Minoru Kobayasi, Isao Yamazaki, Masao Shirouzu et Masataka Yamamoto. « Development of the hypersonic flight experimental vehicle ». Acta Astronautica 40, n^o 2-8 (janvier 1997) : 105–12. http://dx.doi.org/10.1016/s0094-5765(97)00149-5.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

24

Harris, Kenneth D., et Michael Recce. « Experimental modelling of time-of-flight sonar ». Robotics and Autonomous Systems 24, n^o 1-2 (août 1998) : 33–42. http://dx.doi.org/10.1016/s0921-8890(98)00020-7.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

25

Leško, Jakub, Rudolf Andoga, Róbert Bréda, Miriam Hlinková et Ladislav Fözö. « FLIGHT PHASE CLASSIFICATION FOR SMALL UNMANNED AERIAL VEHICLES ». Aviation 27, n^o 2 (5 mai 2023) : 75–85. http://dx.doi.org/10.3846/aviation.2023.18909.

Texte intégral

Résumé :

This article describes research on the classification of flight phases using a fuzzy inference system and an artificial neural network. The aim of the research was to identify a small set of input parameters that would ensure correct flight phase classification using a simple classifier, meaning a neural network with a low number of neurons and a fuzzy inference system with a small rule base. This was done to ensure that the created classifier could be implemented in control units with limited computational power in small affordable UAVs. The functionality of the designed system was validated by several experimental flights using a small fixed-wing UAV. To evaluate the validity of the proposed system, a set of special maneuvers was performed during test flights. It was found that even a simple feedforward artificial neural network could classify basic flight phases with very high accuracy and a limited set of three input parameters.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Scholz, D., C. Borgemeister, R. H. Markham et H. M. Poehling. « Flight initiation and flight activity in Prostephanus truncatus (Coleoptera : Bostrichidae) ». Bulletin of Entomological Research 88, n^o 5 (octobre 1998) : 545–52. http://dx.doi.org/10.1017/s0007485300026067.

Texte intégral

Résumé :

AbstractIn an outdoor experimental set-up, the number of Prostephanus truncatus (Horn) flying from maize cobs was recorded over 38 observation weeks. Flight activity in the field was recorded for 50 weeks with three pheromone traps, each placed at c. 100–300 m from the first experimental set-up. Multiple regression analyses revealed that both flight initiation and flight activity were partly influenced by mean temperatures, but were not directly related. Flight initiation was mainly dependent on population density. An additional experiment showed that sex ratios among pheromone trap catches were not correlated with the number of beetles caught; sex ratios were female-biased throughout the year. Seasonal fluctuations in flight activity recorded with pheromone traps are mainly dependent on changes in the number and sizes of beetle populations in a given area, as well as on breeding site availability and suitability.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Bomphrey, Richard J., Toshiyuki Nakata, Per Henningsson et Huai-Ti Lin. « Flight of the dragonflies and damselflies ». Philosophical Transactions of the Royal Society B : Biological Sciences 371, n^o 1704 (26 septembre 2016) : 20150389. http://dx.doi.org/10.1098/rstb.2015.0389.

Texte intégral

Résumé :

This work is a synthesis of our current understanding of the mechanics, aerodynamics and visually mediated control of dragonfly and damselfly flight, with the addition of new experimental and computational data in several key areas. These are: the diversity of dragonfly wing morphologies, the aerodynamics of gliding flight, force generation in flapping flight, aerodynamic efficiency, comparative flight performance and pursuit strategies during predatory and territorial flights. New data are set in context by brief reviews covering anatomy at several scales, insect aerodynamics, neuromechanics and behaviour. We achieve a new perspective by means of a diverse range of techniques, including laser-line mapping of wing topographies, computational fluid dynamics simulations of finely detailed wing geometries, quantitative imaging using particle image velocimetry of on-wing and wake flow patterns, classical aerodynamic theory, photography in the field, infrared motion capture and multi-camera optical tracking of free flight trajectories in laboratory environments. Our comprehensive approach enables a novel synthesis of datasets and subfields that integrates many aspects of flight from the neurobiology of the compound eye, through the aeromechanical interface with the surrounding fluid, to flight performance under cruising and higher-energy behavioural modes. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Dalah, Entesar Z., Hussein M. Elmahdi, Khalid S. Al Humaidan et Lucy Semerjian. « ESTIMATE OF UAE COMMERCIAL AIRCREW EFFECTIVE DOSES USING CARI-6, EPCARD AND SIEVERT CODES ». Radiation Protection Dosimetry 185, n^o 1 (26 décembre 2018) : 109–15. http://dx.doi.org/10.1093/rpd/ncy280.

Texte intégral

Résumé :

Abstract The aim of this study is to calculate total cruising route effective doses using three commonly used algorithm codes CARI-6, EPCARD and SIEVERT. Further, the impact of flight cruising duration, altitude and latitude on the estimated effective doses will also be investigated. A total of 24 commercial UAE flight data were collected and retrospectively analysed. CARI-6, EPCARD and SIEVERT codes were used to estimate the total route effective doses per single trip of different destinations including USA, Europe, South Africa, Asia and Australia. Aircraft crew effective doses were shown to significantly increase with flying altitude. A strong significant correlation (0.6469; p < 0.05) was obtained between flight duration and the estimated effective doses, while a moderate insignificant correlation (0.3899; p > 0.05) was obtained with flying altitude for all 24 flights using CARI-6. For flights with the same latitude and duration, all codes gave total effective doses within experimental uncertainties.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Kumar, Ashish, Sugjoon Yoon et V. R. Sanal Kumar. « Mixed Reality Simulation of High-Endurance Unmanned Aerial Vehicle with Dual-Head Electromagnetic Propulsion Devices for Earth and Other Planetary Explorations ». Applied Sciences 10, n^o 11 (28 mai 2020) : 3736. http://dx.doi.org/10.3390/app10113736.

Texte intégral

Résumé :

One of the major limitations of existing unmanned aerial vehicles is limited flight endurance. In this study, we designed an innovative uninterrupted electromagnetic propulsion device for high-endurance missions of a quadcopter drone for the lucrative exploration of earth and other planets with atmospheres. As an airborne platform, this device could achieve scientific objectives better than state-of-the-art revolving spacecraft and walking robots, without any terrain limitation. We developed a mixed reality simulation based on a quadcopter drone and an X-Plane flight simulator. A computer with the X-Plane flight simulator represented the virtual part, and a real quadcopter operating within an airfield represented the real part. In the first phase of our study, we developed a connection interface between the X-Plane flight simulator and the quadcopter ground control station in MATLAB. The experimental results generated from the Earth’s atmosphere show that the flight data from the real and the virtual quadcopters are precise and very close to the prescribed target. The proof-of-concept of the mixed reality simulation of the quadcopter at the Earth atmosphere was verified and validated through several experimental flights of the F450 spider quadcopter with a Pixhawk flight controller with the restricted endurance at the airfield location of Hangang Drone Park in Seoul, South Korea. We concluded that the new generation drones integrated with lightweight electromagnetic propulsion devices are a viable option for achieving unrestricted flight endurance with improved payload capability for Earth and other planetary explorations with the aid of mixed reality simulation to meet the mission flight path demands. This study provides insight into mixed reality simulation aiming for Mars explorations and high-endurance missions in the Earth’s atmosphere with credibility using quadcopter drones regulated by dual-head electromagnetic propulsion devices.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Kinney, Lana, et David O’Hare. « Responding to an Unexpected In-Flight Event : Physiological Arousal, Information Processing, and Performance ». Human Factors : The Journal of the Human Factors and Ergonomics Society 62, n^o 5 (25 juin 2019) : 737–50. http://dx.doi.org/10.1177/0018720819854830.

Texte intégral

Résumé :

Objective The study was designed to investigate whether a simulated unexpected abnormal flight event can lead to startle and explore differences in behavioral responses between expected and unexpected abnormal flight events. Background Recent research suggests startle (an autonomic response to an acute stimulus) following unexpected abnormal flight events can impact pilot performance and can increase the probability of a negative outcome following the event. Method Information processing, physiological measures, and performance differences between responses to expected and unexpected flight events were compared. General aviation (GA) pilots flew a series of flights in a fixed-base flight simulator including two experimental flights which included an unexpected and an expected, engine failure. During the flights, heart rate, eye tracking, and flight data were recorded. Results During the unexpected engine failure, pilots showed greater increases in heart rate and pupil dilation. Significant differences in scanning were evident with fewer areas scanned following the unexpected event. During the unexpected engine failure, performance was impaired when compared to the expected events. However, poor performance was not associated with higher levels of arousal. Conclusion The study provides an empirical demonstration of impaired pilot response to unexpected events with associated symptoms consistent with the induction of startle. The present research builds on Landman et al.’s conceptual model of startle and surprise. Application Standardized training protocols may not adequately prepare pilots to deal with the unexpected effects of startle in real-world encounters. Introducing greater variety into training events may be useful. The effects of startle in disrupting well-trained responses may also occur in areas other than aviation where critical events may occur unexpectedly or present in an unfamiliar manner.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Fu, Jingcheng, Jun Huang, Lei Song et Daqing Yang. « Experimental Study of Aircraft Achieving Dutch Roll Mode Stability without Weathercock Stability ». International Journal of Aerospace Engineering 2020 (11 février 2020) : 1–8. http://dx.doi.org/10.1155/2020/8971275.

Texte intégral

Résumé :

Weathercock stability is usually considered essential to achieve normal flight, while the Dutch roll mode stability can still be achieved without weathercock stability which has been algebraically proved. This paper proposed a flight experiment to investigate the characteristics of an airplane with Dutch roll mode stability but no weathercock stability. Firstly, the algebraic analysis based on a standard lateral-directional mode approximation was made to demonstrate the effect of yawing stability derivative Cnβ on the Dutch roll mode characteristics. The flight experiment was organized after that using a model glider which was modified to have zero Cnβ but with marginal change on Cyβ. The convergence of Dutch roll mode in flight meets the algebraic and numerical analysis as expected. However, the difference of handling characteristics between the original and modified configurations indicates some other roles the weathercock stability plays in flight as well as some limitations of utilizing mode criterion in flight quality analysis.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Nievergelt, F., F. Liechti et B. Bruderer. « Migratory directions of free-flying birds versus orientation in registration cages ». Journal of Experimental Biology 202, n^o 16 (15 août 1999) : 2225–31. http://dx.doi.org/10.1242/jeb.202.16.2225.

Texte intégral

Résumé :

Good conditions for migration may promote offshore flights in nocturnal autumn migrants at the northern border of the Mediterranean Sea, whereas unfavourable conditions may induce flights along the coast. These predictions were tested by performing orientation cage experiments and making simultaneous observations of free-flying birds using a tracking radar. The flight directions of free-flying birds were mainly towards southwest and did not differ between overcast and clear sky conditions. The caged birds, however, tended towards southwest under clear sky and showed a more scattered distribution in the southwest and southeast quadrants under overcast conditions. Similar directional scatter occurred when the cage experiments were performed late at night. In contrast, free-flying birds shifted their flight direction towards west as night progressed to avoid flights across the sea. Flight directions observed by radar shifted slightly towards west as the season progressed owing to more frequent southeasterly winds. In orientation cages, however, directional preference was scattered towards southwest and southeast in the early migratory season and became unimodal (southwest) at the peak of the season; this change was not caused by different species composition. Consequently, there is a general coincidence of flight directions and directional preferences in orientation cages, but interpretations of results from orientation cages must allow for the possibility that experimental directions are different from migratory directions of free-flying birds, particularly under suboptimal migratory conditions.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Hedrick, Tyson L., Stacey A. Combes et Laura A. Miller. « Recent developments in the study of insect flight ». Canadian Journal of Zoology 93, n^o 12 (décembre 2015) : 925–43. http://dx.doi.org/10.1139/cjz-2013-0196.

Texte intégral

Résumé :

Here we review recent contributions to the study of insect flight, in particular those brought about by advances in experimental techniques. We focus particularly on the following areas: wing flexibility and deformation, the physiology and biophysics of asynchronous insect flight muscle, the aerodynamics of flight, and stability and maneuverability. This recent research reveals the importance of wing flexibility to insect flight, provides a detailed model of how asynchronous flight muscle functions and how it may have evolved, synthesizes many recent studies of insect flight aerodynamics into a broad-reaching summary of unsteady flight aerodynamics, and highlights new insights into the sources of flight stability in insects. The focus on experimental techniques and recently developed apparatus shows how these advancements have occurred and point the way towards future experiments.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Shpak, Oksana, et Svyatoslav Trostinsky. « HYBRID DRONES WITH DUCTED AND ASYMMETRIC PROPELLERS : EXPERIMENTAL STUDIES AND APPLICATION PROSPECTS ». Measuring Equipment and Metrology 85, n^o 4 (2024) : 43–50. https://doi.org/10.23939/istcmtm2024.04.043.

Texte intégral

Résumé :

This article presents a comprehensive analysis of hybrid unmanned aerial vehicles (UAVs) equipped with ducted and asymmetric propellers. The results of experimental studies confirm the advantages of using these types of propellers regarding aerodynamic efficiency, energy efficiency, noise reduction, and improved maneuverability. The possibility of combining asymmetric propellers with ducted designs, as well as their impact on thrust, flight stability, and other flight characteristics of drones, is examined in detail. Comparative tables and graphs of the results highlight key performance indicators. Particular attention is paid to the analysis of the application of drones with such propellers in urban conditions, and recommendations for further research and technology implementation are developed.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Li, Shun, Gong Duo Zhang, Shi Hui Bi, Xiao Tang Li et Guo Wei Xie. « Experimental Investigation on Influence of Important Parameters in Centrifugal Granulation for MBFS ». Advanced Materials Research 968 (juin 2014) : 202–5. http://dx.doi.org/10.4028/www.scientific.net/amr.968.202.

Texte intégral

Résumé :

The difficulties of molten metallurgical slag heat recovery caused by low thermal conductivity and high enthalpy are analyzed.Centrifugal granulation is an environment-friendly process in treating the slag. The existing researches on centrifugal granulation are concentrated in the shape, size and mass distribution of slag particles. The relations between flight distance of slag, divorced speed of slag and outside speed of cup and rotary speed and rotary cup diameter were studied. The experimental results indicate that flight distance is farther from the cup and the speeds increase with increasing rotary speed. While rotary speed reaches 1000 rpm, divorced speed and flight distance of slag are almost invariant. When rotary cup diameter increases, the flight distance and the speeds increase simultaneously. Flight is reasonably simplified as:uniform motion in horizontal direction and motion of free falling body in the vertical direction,The experimental results have certain guiding significance to design of heat recovery equipment.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Meda, T., et A. Rogala. « Experimental Validation of the Mean Pitch Theory ». Journal of Physics : Conference Series 2090, n^o 1 (1 novembre 2021) : 012042. http://dx.doi.org/10.1088/1742-6596/2090/1/012042.

Texte intégral

Résumé :

Abstract There are several types of exterior ballistic models used to calculate projectile’s flight trajectories. The most complex 6 degree of freedom rigid body model has many disadvantages to using it to create firing tables or rapid calculations in fire control systems. Some of ballistic phenomena can be simplified by empirical equations without significant loss of accuracy. This approach allowed to create standard NATO ballistic model for spin stabilized projectiles named Modified Point of Mass Model (PM Model). For fin (aerodynamically) stabilized projectiles like mortar projectiles simple Point of Mass Model is commonly used. The PM Model excludes many flight phenomena in calculations. In this paper authors show the mean pitch theory as an approximation of the natural fin stabilised projectile pitch during flight. The theory allows for simple improvement of accuracy of the trajectories calculation. In order to validate the theory data obtained from shooting of supersonic mortar projectiles were used. The comparison of accuracy between simple PM Model and PM Model including mean pitch theory were shown. Results were also compared with the angle of response theory.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Ramšak, Matjaž. « Radio Controlled Sailplane Flight : Experimental and Numerical Analysis ». Strojniški vestnik – Journal of Mechanical Engineering 58, n^o 3 (15 mars 2012) : 147–55. http://dx.doi.org/10.5545/sv-jme.2009.153.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

38

Blanchard, Robert C., Thomas A. Ozoroski et John Y. Nicholson. « Shuttle upper atmosphere mass spectrometer experimental flight results ». Journal of Spacecraft and Rockets 31, n^o 4 (juillet 1994) : 562–68. http://dx.doi.org/10.2514/3.26479.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

39

Kang, Chang-kwon, Jacob Cranford, Madhu K. Sridhar, Deepa Kodali, David Brian Landrum et Nathan Slegers. « Experimental Characterization of a Butterfly in Climbing Flight ». AIAA Journal 56, n^o 1 (janvier 2018) : 15–24. http://dx.doi.org/10.2514/1.j055360.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Avans, Diana, et Kip Smith. « Experimental Investigations of Pilot Workload in Free Flight ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 40, n^o 24 (octobre 1996) : 1259. http://dx.doi.org/10.1177/154193129604002416.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

41

Bobylev, A. V., V. A. Yaroshevskii, A. M. Zashchirinskii et K. M. Pichkhadze. « Experimental Flight of a Spacecraft with Solar Sail ». Cosmic Research 41, n^o 6 (novembre 2003) : 612–27. http://dx.doi.org/10.1023/b:cosm.0000007961.72706.cd.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

42

Fields, Lanny. « Remarks Regarding Catania’s “The Flight from Experimental Analysis” ». European Journal of Behavior Analysis 13, n^o 2 (décembre 2012) : 201–5. http://dx.doi.org/10.1080/15021149.2012.11434423.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

43

Bolotov, V. N., S. N. Gninenko, R. M. Djilkibaev, V. V. Isakov, Yu M. Klubakov, V. D. Laptev, V. M. Lobashev et al. « The experimental study of the decay in flight ». Nuclear Physics B - Proceedings Supplements 16 (août 1990) : 459–61. http://dx.doi.org/10.1016/0920-5632(90)90551-5.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

44

Bolotov, V. N., S. N. Gninenko, R. M. Djilkibaev, V. V. Isakov, Yu M. Klubakov, V. D. Laptev, V. M. Lobashev et al. « The experimental study of the decay in flight ». Physics Letters B 243, n^o 3 (juin 1990) : 308–12. http://dx.doi.org/10.1016/0370-2693(90)90857-3.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

45

Johnson, Eric N., et Amy R. Pritchett. « Experimental Study of Vertical Flight Path Mode Awareness ». IFAC Proceedings Volumes 28, n^o 15 (juin 1995) : 153–58. http://dx.doi.org/10.1016/s1474-6670(17)45225-6.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

46

Karssies, H. J., et C. De Wagter. « Extended incremental non-linear control allocation (XINCA) for quadplanes ». International Journal of Micro Air Vehicles 14 (janvier 2022) : 175682932110708. http://dx.doi.org/10.1177/17568293211070825.

Texte intégral

Résumé :

Hybrid UAVs have gained a lot of interest for their combined vertical take-off & landing (VTOL) and efficient forward flight capabilities. But their control is facing challenges in over-actuation and conflicting requirements depending on the flight phase which can easily lead to actuator saturation. Incremental Non-linear Control Allocation (INCA) has been proposed to solve the platform’s control allocation problem in the case of saturation or over-actuation by minimizing a set of objective functions. This work demonstrates INCA on quadplanes, an in-plane combination between a quadrotor and a conventional fixed-wing, and proposes an extension to control the outer loop. The novel controller is called Extended INCA (XINCA) and adds the wing orientation as a force-generating actuator in the outerloop control optimization. This leads to a single controller for all flight phases that avoids placing the wing at negative angles of attack and minimizes the load on hover motors. XINCA has low dependence on accurate vehicle models and requires only several optimization parameters. Flight simulations and experimental flights are performed to demonstrate the performance.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Duivenvoorden, Ramon, Mark Voskuijl, Lars Morée, Jan de Vries et Finbar van der Veen. « Numerical and Experimental Investigation into the Aerodynamic Benefits of Rotorcraft Formation Flight ». Journal of the American Helicopter Society 67, n^o 1 (1 janvier 2022) : 1–17. http://dx.doi.org/10.4050/jahs.67.012011.

Texte intégral

Résumé :

The use of formation flight to achieve aerodynamic benefit applied to rotorcraft has, unlike its fixed-wing counterpart, received little attention in the literature. This document presents a proof-of-concept of rotorcraft formation flight from two independent investigations: a numerical study of a fully articulated helicopter influenced by an upstream helicopter wake and a wind-tunnel experiment featuring two small-scale helicopter models with fixed-pitch blades. Both cases feature a representation of two helicopters in a diagonal, staggered formation aligned on the advancing side of the main rotor, but do not simulate directly comparable flight conditions. The vertical and lateral alignment of the two helicopters is varied in order to observe the achievable reductions in main rotor power required during cruise flight. The wind-tunnel experiment data yield an estimated maximum total power reduction for the secondary aircraft of approximately 24%, while the numerical models yield reductions between 20% and 34% dependent on flight velocity. Both experiments predict a higher potential for aerodynamic benefit than generally observed for fixed-wing formations, which is attributed to the asymmetric velocity profile induced by the wake of the upstream rotor. Optimal lateral alignment of both experimental and numerical results is found to feature overlap of the rotor disk areas, rather than tip-to-tip alignment, as a result of the circular rotor disk area. Experimental data show an optimal vertical alignment of the secondary rotorcraft below the primary, due to the self-induced vertical displacement of the rotor wake, which is absent from the numerical results due to the application of a flat wake assumption. The results show a promising potential for rotorcraft formation flight, though due to the limited nature of the models used, conclusions cannot be generalized. The potential aerodynamic benefit indicated by the present study invites further research in the field of rotorcraft formation flight.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Duivenvoorden, Ramon, Mark Voskuijl, Lars Morée, Jan de Vries et Finbar van der Veen. « Numerical and Experimental Investigation into the Aerodynamic Benefits of Rotorcraft Formation Flight ». Journal of the American Helicopter Society 67, n^o 1 (1 janvier 2022) : 1–17. http://dx.doi.org/10.4050/jahs.67.012011.

Texte intégral

Résumé :

The use of formation flight to achieve aerodynamic benefit applied to rotorcraft has, unlike its fixed-wing counterpart, received little attention in the literature. This document presents a proof-of-concept of rotorcraft formation flight from two independent investigations: a numerical study of a fully articulated helicopter influenced by an upstream helicopter wake and a wind-tunnel experiment featuring two small-scale helicopter models with fixed-pitch blades. Both cases feature a representation of two helicopters in a diagonal, staggered formation aligned on the advancing side of the main rotor, but do not simulate directly comparable flight conditions. The vertical and lateral alignment of the two helicopters is varied in order to observe the achievable reductions in main rotor power required during cruise flight. The wind-tunnel experiment data yield an estimated maximum total power reduction for the secondary aircraft of approximately 24%, while the numerical models yield reductions between 20% and 34% dependent on flight velocity. Both experiments predict a higher potential for aerodynamic benefit than generally observed for fixed-wing formations, which is attributed to the asymmetric velocity profile induced by the wake of the upstream rotor. Optimal lateral alignment of both experimental and numerical results is found to feature overlap of the rotor disk areas, rather than tip-to-tip alignment, as a result of the circular rotor disk area. Experimental data show an optimal vertical alignment of the secondary rotorcraft below the primary, due to the self-induced vertical displacement of the rotor wake, which is absent from the numerical results due to the application of a flat wake assumption. The results show a promising potential for rotorcraft formation flight, though due to the limited nature of the models used, conclusions cannot be generalized. The potential aerodynamic benefit indicated by the present study invites further research in the field of rotorcraft formation flight.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Бойко, Татьяна Сергеевна. « МЕТОДИКА ТЕОРЕТИЧЕСКОЙ ОЦЕНКИ ИНТЕГРАЛЬНОЙ ПОВТОРЯЕМОСТИ ПЕРЕГРУЗОК, ДЕЙСТВУЮЩИХ НА САМОЛЕТ В ТИПОВОМ ПОЛЕТЕ ». Aerospace technic and technology, n^o 3 (15 juillet 2019) : 35–41. http://dx.doi.org/10.32620/aktt.2019.3.04.

Texte intégral

Résumé :

One of the most significant characteristics of the aircraft is its resource. Airplane elements are subject to fatigue damage in operation. For a theoretical assessment of the accumulated fatigue damage, durability and design life, it is necessary to know the loads acting on the aircraft. The main contribution to fatigue damage is made by loads from gusts which are of a random nature. The magnitude of this damage depends on the flight conditions, namely on the flight speed, altitude, and aircraft weight. With good accuracy, the loading process of the structure in flight can be described using the overloads integral repeatability at the center of gravity of the aircraft. This function is obtained experimentally in flight tests. However, the article proposes a method for calculating the function of the overloads increments integral repeatability at the design stage. This approach allows us to take into account the expected operating conditions of the aircraft being created and to assess its loading. Using the standard flight profiles and the relative flight time over them, the loading conditions for the generalized typical flight were obtained. The reliability of the proposed method was confirmed by comparing the theoretical and experimental data on the overloads integral repeatabilities per flight for various aircraft of IL-76T type. The typical flights' profiles of the Il-76T (TD) aircraft fleet were compiled by the author earlier by statistical processing of the forms data of these airplanes. As a result, good agreement was obtained between the calculated and measured curves of the overloads integral repeatabilities. Accounting for various typical profiles allowed to explain the variation of experimental data. The possibility of a theoretical estimate of the maximum overload of the ground-air-ground cycle is shown. This parameter can contribute more than half of the fatigue damage to the structure per flight and requires precise determination. In general, the developed method for calculating the overloads integral repeatability at the center of gravity later serves to calculate the design, accumulated and residual life of the transport category aircraft, taking into account the intended operating history.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Geng, Lisong, Zefeng Wang, Honglin Zhang et Qianqian Yang. « Experimental research of helicopter blade load in flight based on optical sensing ». Journal of Physics : Conference Series 2879, n^o 1 (1 octobre 2024) : 012062. http://dx.doi.org/10.1088/1742-6596/2879/1/012062.

Texte intégral

Résumé :

Abstract The actual flight measurement of blade load is an extremely important part of the new helicopter. In order to solve the problems existing in the traditional electrical measurement method, such as weak anti-interference ability, short life, and large added mass, a flight measurement method of blade load based on optical sensing is proposed. Firstly, the strain mode distribution law is obtained by calculating the dynamic response of the real blade. The optimal layout of the optical fiber measurement points is determined. Through theoretical analysis of strain transferring and experimental verification, a highly reliable fusion scheme of blade and fiber is designed to meet the flight requirements. Based on the power line carrier technology, the optical sensing test system for helicopter flight test is developed. The flight test of blade load is completed successfully. The results of optical fiber measurement are consistent with the results of traditional electrical measurement, which indicates that the optical sensing technology has good applicability in the measurement of helicopter blade load. At the same time, it has been proved that the optical measurement system set is reliable and durable. It is of great significance for the leap from electric measurement to optical measurement.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Experimental flight »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres