Viability of joined flight for small unmanned aerial vehicles

2019 ◽  
Vol 124 (1273) ◽  
pp. 297-322
Author(s):  
E. Levis ◽  
F. Pleho ◽  
J. Hedges
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Parametric Analysis ◽  
Aircraft Design ◽  
Relative Magnitude ◽  
Design Parameters ◽  
Wing Loading ◽  
Aerodynamic Efficiency ◽  
Aspect Ratios ◽  
Aerial Vehicles ◽  
Better Than

ABSTRACTThe range of small, electrically powered UAVs is still limited by the mass specific energy of batteries. This paper investigates the idea that, in cases where multiple aircraft must transit to the same location, savings in mass or an extension of achievable range are possible when they join wingtip-to-wingtip. The viability of joined flight is investigated by quantifying the relative magnitude of savings resulting from increased aerodynamic efficiency and that of penalties due to the increased structural and component weights. Through a parametric analysis the level of savings achievable is found to be greatly dependent on the proportion of the flight spent in a joined configuration and aircraft design parameters such as wing loading, aspect ratio and the added weight of the joining mechanism. A custom, multidisciplinary UAV sizing algorithm is presented and utilised to design several sample aircraft, featuring two different joining mechanism architectures. The results verify the findings of the parametric study and indicate that mass savings are possible only for moderate to low aspect ratios, with semi-permanent magnetic joining mechanism performing better than rigid structural ones, even when the joined fight segment accounts for only 30% of the total airborne time.

scholarly journals Simulation and Test of Discrete Mobile Surfaces for a RC-Aircraft

Aerospace ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 122
Author(s):  
Francesco Nicassio ◽  
Gennaro Scarselli
Keyword(s):  
Composite Materials ◽  
Unmanned Aerial Vehicles ◽  
Composite Plate ◽  
Stacking Sequence ◽  
Total Thickness ◽  
Aerodynamic Efficiency ◽  
Aerodynamic Pressure ◽  
Aerial Vehicles ◽  
Discrete Surface ◽  
Lever Effect

Morphing structures suitable for unmanned aerial vehicles (UAVs) have been investigated for several years. This paper presents a novel lightweight, morphing concept based on the exploitation of the “lever effect” of a bistable composite plate that can be integrated in an UAV horizontal tail. Flight dynamics equations are solved in Simulink environment, thus being able to simulate and compare different flight conditions with conventional and bistable command surfaces. Subsequently, bistable plates are built by using composite materials, paying particular attention to dimensions, asymmetric stacking sequence and total thickness needed to achieve bistability. NACA0011 airfoil is chosen for proving this concept. Wind tunnel tests demonstrate that the discrete surface is capable of withstanding the aerodynamic pressure. A remotely piloted vehicle is employed to test the discrete horizontal tail command during the take-off. The results show that, choosing a proper configuration of constraints, stacking sequence and aspect ratio for the bistable laminate, it is possible to tailor the snap-through mechanism. The proposed concept appears lighter and increases aerodynamic efficiency when compared to conventional UAV command surfaces.

scholarly journals The Wane of Command: Evidence on Drone Strikes and Control within Terrorist Organizations

2020 ◽  
pp. 1-20
Author(s):  
ANOUK S. RIGTERINK
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Natural Experiment ◽  
Terrorist Attacks ◽  
Terrorist Organizations ◽  
Aerial Vehicles ◽  
Terrorist Groups ◽  
Drone Strikes ◽  
And Control ◽  
The Impact ◽  
Better Than

This paper investigates how counterterrorism targeting terrorist leaders affects terrorist attacks. This effect is theoretically ambiguous and depends on whether terrorist groups are modeled as unitary actors or not. The paper exploits a natural experiment provided by strikes by Unmanned Aerial Vehicles (drones) “hitting” and “missing” terrorist leaders in Pakistan. Results suggest that terrorist groups increase the number of attacks they commit after a drone “hit” on their leader compared with after a “miss.” This increase is statistically significant for 3 out of 6 months after a hit, when it ranges between 47.7% and 70.3%. Additional analysis of heterogenous effects across groups and leaders, and the impact of drone hits on the type of attack, terrorist group infighting, and splintering, suggest that principal-agent problems—(new) terrorist leaders struggling to control and discipline their operatives—account for these results better than alternative theoretical explanations.

scholarly journals An Extended Methodology for Sizing Solar Unmanned Aerial Vehicles: Theory and Development of a Python Framework for Design Assist

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7541
Author(s):  
José Roberto Cândido da Silva ◽  
Gefeson Mendes Pacheco
Keyword(s):  
Remote Sensing ◽  
Sensitivity Analysis ◽  
Solar Cells ◽  
Unmanned Aerial Vehicles ◽  
Total Weight ◽  
Design Parameters ◽  
Solar Photovoltaic ◽  
Python Language ◽  
Aerial Vehicles ◽  
Diverse Application

There is a growing interest in using unmanned aerial vehicles (UAVs) in the most diverse application areas from agriculture to remote sensing, that determine the need to project and define mission profiles of the UAVs. In addition, solar photovoltaic energy increases the flight autonomy of this type of aircraft, forming the term Solar UAV. This study proposes an extended methodology for sizing Solar UAVs that take off from a runway. This methodology considers mission parameters such as operating location, altitude, flight speed, flight endurance, and payload to sizing the aircraft parameters, such as wingspan, area of embedded solar cells panels, runway length required for takeoff and landing, battery weight, and the total weight of the aircraft. Using the Python language, we developed a framework to apply the proposed methodology and assist in designing a Solar UAV. With this framework, it was possible to perform a sensitivity analysis of design parameters and constraints. Finally, we performed a simulation of a mission, checking the output parameters.

scholarly journals Aerodynamic efficiency and performance enhancement of fixed-wing unmanned aerial vehicles using novel configurations and techniques

2018 ◽  
Author(s):  
Περικλής Παναγιώτου
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Performance Enhancement ◽  
Operating Conditions ◽  
Aerodynamic Efficiency ◽  
Aerial Vehicles ◽  
And Performance

Ο σκοπός της διδακτορικής διατριβής είναι η βελτιστοποίηση της αεροδυναμικής απόδοσης και των επιδόσεων Μη-Επανδρωμένων Αεροχημάτων (ΜΕΑ) σταθερής πτέρυγας, μεγάλης αυτονομίας και μέσου ύψους (MALE UAV ή tactical UAV – NATO classification), που επιχειρούν σε συνθήκες πτήσης με Mach < 0.3. Πρόκειται για μια πλήρη τεχνολογική έρευνα, τα βασικά αντικείμενα της οποίας είναι α) η διερεύνηση της ροής γύρω από ΜΕΑ σταθερής πτέρυγας, β) η ανάλυση του ισοζυγίου οπισθέλκουσας δύναμης και εντοπισμός των κύριων πηγών αυτής, γ) η αναζήτηση, καταγραφή, και αξιολόγηση πιθανών τεχνολογιών, γεωμετριών, και τεχνικών για τη βελτίωση της αεροδυναμικής απόδοσης και των επιδόσεων ΜΕΑ (technology screening), δ) η επιλογή και λεπτομερής διερεύνηση των γεωμετριών που δυνητικά προσφέρουν τα περισσότερα πλεονεκτήματα, και ε) η εφαρμογή των παραπάνω σε εφαρμοσμένες μελέτες σχεδιασμού ΜΕΑ για αξιολόγηση και εκτίμηση επιδόσεων. Σε αντίθεση με τις υπάρχουσα βιβλιογραφία, η παρούσα έρευνα προσεγγίζει ολιστικά τον σχεδιασμό και την βελτιστοποίηση των ΜΕΑ σταθερής πτέρυγας, εκκινώντας από θεμελιώδεις ρευστοδυναμικές αναλύσεις, συνεχίζοντας με παραμετρικές αναλύσεις αεροδυναμικής, και κλείνοντας με εφαρμογή σε ολοκληρωμένες μελέτες σχεδιασμού. Για αυτό το σκοπό χρησιμοποιείται μια πληθώρα εργαλείων, που περιλαμβάνουν λογισμικά υπολογιστικής μοντελοποίησης, πειραματικές διατάξεις και τεχνικές, καθώς επίσης και αναλυτικά εργαλεία διαστασιολόγησης, και υπολογισμού παραμέτρων αεροδυναμικής, ευστάθειας και επιδόσεων αεροχημάτων, που αναπτύχθηκαν στα πλαίσια της διατριβής (in-house tools). Αρχικά καθορίζεται και σχεδιάζεται μια γεωμετρία αναφοράς ΜΕΑ, της οποίας οι προδιαγραφές (requirements) και οι επιχειρησιακές συνθήκες (operating conditions) ορίζονται επίσης ως σημεία αναφοράς. Η ροή γύρω από το ΜΕΑ αναλύεται χρησιμοποιώντας τα εργαλεία αεροδυναμικής ανάλυσης και πραγματοποιείται μια ταξινόμηση της οπισθέλκουσας δύναμης (drag bookkeeping), τόσο για την κύρια πτέρυγα, όσο και για την συνολική γεωμετρία του ΜΕΑ. Στη συνέχεια, ερευνάται μια πληθώρα πιθανών επιλογών, τεχνολογιών, τεχνικών και γεωμετριών, που δυνητικά μπορεί να βελτιώσουν την επίδοση των ΜΕΑ σταθερής πτέρυγας. Δύο είδη γεωμετριών επιλέγονται τελικά για ενδελεχή μελέτη και περεταίρω ανάλυση, και συγκεκριμένα, τα winglets και τα σώματα BWB. Οι γεωμετρίες αυτές αναλύονται διεξοδικά σε υπολογιστικό, πειραματικό, και σχεδιαστικό επίπεδο. Όπως πιστοποιείται και από τις σχετικές επιστημονικές δημοσιεύσεις, η έρευνα οδηγεί σε πρωτότυπα συμπεράσματα και παρατηρήσεις που αφορούν τα ροϊκά φαινόμενα, και σε ανάπτυξη εξειδικευμένων μεθοδολογιών σχεδιασμού για εφαρμογές ΜΕΑ σταθερής πτέρυγας. Γίνεται επίσης και αποτίμηση των πλεονεκτημάτων της χρήσης των γεωμετριών αυτών, με τα αποτελέσματα να δείχνουν βελτίωση της τάξεως του 10% και 30% για τα winglets και τις πλατφόρμες BWB αντίστοιχα, όσον αφορά την αεροδυναμική απόδοση. Συνοψίζοντας, η διατριβή επικεντρώνεται στα ΜΕΑ τύπου MALE/tactical, λόγω του ότι αποτελούν το μεγαλύτερο κομμάτι της αγοράς των ΜΕΑ. Ωστόσο, με την προϋπόθεση ότι οι λόγοι ροϊκής ομοιότητας και οι επιχειρησιακές συνθήκες είναι πανομοιότυπες, οι προτεινόμενες μέθοδοι και τα επαγόμενα συμπεράσματα μπορούν να επεκταθούν και σε οποιοδήποτε άλλο αερόχημα σταθερής πτέρυγας, από ΜΕΑ μεγαλύτερης κλίμακας, μέχρι υπερ-ελαφρά ή ελαφρά αεροχήματα και μεταγωγικά αεροσκάφη. Επιπρόσθετα, η έρευνα που αφορά είτε σε στοιχειώδη ρευστοδυναμικά φαινόμενα, όπως είναι οι δίνες ακροπτερυγίου, είτε στις βελτιωτικές διατάξεις (winglets, BWB) έχει προεκτάσεις και σε άλλες εφαρμογές μεγαλύτερης κλίμακας, που αφορούν την κοινωνία και την βιομηχανία, όπως είναι για παράδειγμα τα επιβατηγά αεροσκάφη και οι εναέριες μεταφορές.

Methodological approach to integrated effectiveness assessment apply of aviation systems with UAVs. Evaluating methods for effectiveness of solving radio technical reconnaissance and aircraft destruction of targets tasks

2021 ◽  
Author(s):  
D.G. Pantenkov
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Functional Dependence ◽  
Methodological Approach ◽  
Practical Significance ◽  
Design Parameters ◽  
Mathematical Apparatus ◽  
Optoelectronic System ◽  
Industrial Enterprises ◽  
Aerial Vehicles ◽  
Integral Assessment

Currently, the use of aviation systems with unmanned aerial vehicles (UAVs) of various classes and purpose for the benefit of both special customers and civilian purposes has acquired particular relevance and practical significance. Modern UAVs, used both separately and as part of the group, can carry several target loads on board at the same time, built on various physical principles: multifunctional optoelectronic system, digital aerial photography system, on-board radar station, radio and radio reconnaissance system, communication system for transmitting data from target loads (sensors) to a mobile device (for example, a tablet) to a remote subscriber, etc. At the same time, the issue of determining the evaluation of the effectiveness of solving both individual target tasks of UAVs and finding an integral assessment of the effectiveness of using aircraft systems with UAVs when solving a set of target tasks (sequentially or sequentially-in parallel in time), taking into account their priority and a number of other factors, remains practically unlit. The scientific and technical article consists structurally of three parts and is devoted to the consideration of the issues of finding an integral assessment of the effectiveness of the use of aviation systems with unmanned aerial vehicles. In the first part of article [1], a scientific and methodological approach has been developed to determine estimates of the effectiveness of solving private target problems of radio communication and remote monitoring (by optical and radar means) by a complex with UAVs. The second part of the article presents a mathematical apparatus for assessing the effectiveness of solving problems of conducting radio-technical reconnaissance and aircraft destruction of targets. As a criterion for the effectiveness of solving all private target problems, a universal indicator of the probability of solving them has been adopted, which will ultimately allow for convolution and determine an integral assessment of the effectiveness of solving a whole set of target problems. The methodological apparatus developed in the article is universal and invariant to the input parameters, that is, the number of solved target problems, the stage of operation of the complex with UAVs, and can be easily adapted to the new conditions for the use of other complexes with UAVs. Within the framework of this approach, a mathematical apparatus for functional dependence of probabilities of solving particular target problems with design parameters of target loads in the UAV has been developed, taking into account the peculiarities of its functioning and in the conditions of existing restrictions and assumptions. The scientific and methodological approach allows already at the stage of formation of the tactical and technical task for the complex with UAVs to obtain quantitative estimates of the probabilities of solving private target tasks using the technical backlog of industrial enterprises for key components from the complex (target loads, a set of communication facilities, etc.). Finding effectiveness estimates in the group application of UAVs, as well as taking into account possible electronic counteraction, goes beyond the scope of this article and is the direction of further research on this topic.

scholarly journals A computer application for parametric aircraft design

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Filipe R. Fraqueiro ◽  
Pedro F. Albuquerque ◽  
Pedro V. Gamboa
Keyword(s):  
User Interface ◽  
Unmanned Aerial Vehicles ◽  
Graphical User Interface ◽  
Aircraft Design ◽  
Computer Application ◽  
Preliminary Design ◽  
Two Dimensional ◽  
Design Phase ◽  
Aerial Vehicles

Abstract The present work describes the development and final result of a graphical user interface tailored for a mission-based parametric aircraft design optimization code which targets the preliminary design phase of unmanned aerial vehicles. This development was built from the XFLR5 open source platform and further benefits from two-dimensional aerodynamic data obtained from XFOIL. For a better understanding, the most important graphical windows are shown. In order to demonstrate the graphical user interface interaction with the aircraft designer, the results of a case study which maximizes payload are presented.

Planning the search for separating parts of the launch vehicle using a group of unmanned aerial vehicles

2020 ◽  
Author(s):  
V.I. Goncharenko ◽  
G.N. Lebedev ◽  
D.A. Mikhaylin
Keyword(s):  
Genetic Algorithm ◽  
Unmanned Aerial Vehicles ◽  
Launch Vehicles ◽  
Maintenance Schedule ◽  
Mobile Objects ◽  
Aerial Vehicles ◽  
The Right ◽  
Original Approach ◽  
Research Show ◽  
Better Than

The paper deals with the processes of maintaining a special class of mobile objects, whose schedules are either given or require preassignment in order to maintain these objects at the right time and in the right place. The posed problem of planning the flight of a group of aerial vehicles is solved using a continuous form of dynamic programming, according to which the Bellman equation in partial derivatives corresponds to the optimality condition. An original approach to solving the problem of pre-flight and operational planning of actions of a group of unmanned aerial vehicles based on a genetic algorithm is proposed. The fundamental difference between the problem being solved and the well-known traveling salesman problem is in taking into account the required maintenance schedule. The developed planning automation tool makes it possible to increase the efficiency of measures to detect separating parts of launch vehicles using a group of unmanned aerial vehicles. Findings of research show that the developed genetic algorithm is better not only than algorithms based on one-parameter and two-parameter criteria, but even better than algorithms based on a three-parameter criterion.

scholarly journals Aerodynamic Performance of an Octorotor SUAV with Different Rotor Spacing in Hover

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1364
Author(s):  
Yao Lei ◽  
Yuhui Huang ◽  
Hengda Wang
Keyword(s):  
Flow Field ◽  
Unmanned Aerial Vehicles ◽  
Aerodynamic Performance ◽  
Aerodynamic Efficiency ◽  
Experimental Platform ◽  
Vorticity Distribution ◽  
Aerial Vehicles ◽  
Spacing Ratio ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

To study the aerodynamic performance of hovering octorotor small unmanned aerial vehicles (SUAV) with different rotor spacing, the computational fluid dynamics (CFD) method is applied to analyze the flow field of an octorotor SUAV in detail. In addition, an experimental platform is built to measure the thrust and power of the rotors with rotor spacing ratios L/D of 1.0, 1.2, 1.4, 1.6, and 1.8, sequentially. According to the theory of momentum, rotor aerodynamic performance is obtained with qualitative analysis. Further analysis with numerical simulation is presented with the flow field of the octorotor SUAV, the vorticity distribution, velocity distribution, pressure distribution, and streamline. The results show that the aerodynamic performance varies with the rotor spacing. Specifically, the aerodynamic performance is poor at L/D = 1.0, which is accompanied with strong interaction of wake and tip vortexes and interaction with each other. However, the aerodynamic efficiency is much improved with a larger rotor spacing, especially achieving the highest at L/D = 1.8, which is considered to be the best rotor spacing ratio for this kind of octorotor SUAV.

AggieVTOL

2012 ◽  
pp. 85-121
Author(s):  
Brandon J. Stark ◽  
YangQuan Chen ◽  
Mac McKee
Keyword(s):  
Learning Curve ◽  
Unmanned Aerial Vehicles ◽  
Aerospace Industry ◽  
Design Parameters ◽  
Research Groups ◽  
Steep Learning Curve ◽  
Aerial Vehicles ◽  
Rotorcraft Uav ◽  
Performance Results

Unmanned Aerial Vehicles (UAVs) for civilian applications are in a rapidly growing sector in the global aerospace industry that has only recently begun to gain traction. In this relatively immature field, there is such a steep learning curve that it can be difficult for research groups to begin development of well designed UAV systems. In this chapter, the authors present the AggieVTOL, a modular multi-rotor rotorcraft UAV prototype platform, and an overview of prototyping phase of its development, including design parameters and the implementation of its modular subsystems. Performance results demonstrate the effectiveness of platform.

scholarly journals Investigation of a Cruising Fixed Wing Mini Unmanned Aerial Vehicle Performance Optimization

2019 ◽  
Vol 4 (2) ◽  
pp. 280-293
Author(s):  
Shahrooz Eftekhari ◽  
Abdulkareem Sh. Mahdi Al-Obaidi
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Unmanned Aerial Vehicle ◽  
Performance Optimization ◽  
Experimental Validation ◽  
Vehicle Performance ◽  
Aerodynamic Efficiency ◽  
Aerial Vehicles ◽  
Military Applications ◽  
Aerial Vehicle ◽  
Wing Geometry

The applications of unmanned aerial vehicles have been extended through the recent decades and they are utilized for both civil and military applications. The urge to utilize unmanned aerial vehicles for civil purposes has elevated researchers and industries interest towards the mini unmanned aerial vehicle (MUAV) category due to its suitable configurations and capabilities for multidisciplinary civil purposes. This study is an effort to further enhance the aerodynamic efficiency of MUAVs through a parametric study of the wing and proposing an innovative bioinspired wing design. The research is conducted utilizing numerical simulation and experimental validation. This research provides a better understanding of different wing parameter(s) effect on the aerodynamic performance of the wing and mini unmanned aerial vehicles. A new wing configuration is designed, implemented and evaluated. The wing is named as Alpine since it is inspired by biomimicry of alpine swift bird. Evaluation of the new wing geometry shows that the Alpine wing geometry performs 35.9% more efficient compared to an existing wing with similar wing area. Hence, the aerodynamic efficiency optimization is achieved for the Alpine wing which helps to enhance the performance of MUAVs.

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