DOCSLIB.ORG

A Study of Helicopter Aerodynamics in Ground Effect

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Study of Helicopter Aerodynamics in Ground Effect A STUDY OF HELICOPTER AERODYNAMICS IN GROUND EFFECT DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Devi Prasad Pulla, B.E., M.S. * * * * * The Ohio State University 2006 Dissertation Committee: Approved by A.T. Conlisk, Adviser S.Mazumder Adviser John Yu Graduate Program in Igor Adamovich Mechanical Engineering ABSTRACT The flow around a helicopter is very complex; it becomes much more complex when it comes close to the ground. The presence of the ground changes the aerodynamic char- acteristics of the rotor and the flow environment becomes much more complex compared with that of flight out-of-ground effect (OGE) and hence the behavior of the rotor wake in the vicinity of the ground is challenging to predict. Under in-ground-effect(IGE) condi- tions, the wake collides with the ground and causes a significant perturbation to the flow near the blade. Significant interactions between the main rotor wake and the ground have been associated with the formation and passage of the ground vortex in forward flight. The presence of a ground vortex affects the handling qualities of the helicopter. The aim of this research is to capture the physics of the flow features and dynamics of ground effect flows around a rotorcraft, provide an understanding of the rotor wake/vortices near the ground, and generate rigorous models to accurately predict handling qualities, loads and moments acting on the rotor and the power requirements. A free vortex method is used to model the flowfield. The presence of the ground is modeled using the method of images and the lifting-surface theory is used to model each rotor blade. An initial wake geometry is assumed which is allowed to develop in time until the flowfield becomes periodic. The rotor wake is assumed to consist of only the tip ii vortices and the inboard sheet and the root vortex are neglected. The solution is stepped in time using an Adams-Moulton scheme with a Runge-Kutta starting formula. The wake structure after periodicity is reached is obtained for hover and different for- ward flight speeds. Also, the nature of the flowfield, as well as the formation of the ground vortex, is understood by obtaining the velocity contours on a longitudinal plane containing the rotor blade after periodicity is obtained. The unsteadiness in the velocities is quantified by obtaining the RMS deviation in velocities on different planes containing the tail rotor around the rotor disk simulating the various kinds of flight. Thrust and power requirements on the rotor disk have been predicted and have been successfully validated by comparison with experimental results obtained from Georgia Institute of Technology. A tail rotor has also been included in the current model to understand its implications on the wake struc- ture and loads. The computational results have been validated against experimental results obtained at Georgia Institute of Technology and Empey and Ormiston. iii ACKNOWLEDGMENTS Personal gratitude is extended to Professor A.T. Conlisk whose patience and guidance is greatly appreciated. I would also like to thank Mr.Alan Egolf for his helpful input regarding my research. This work is supported under Task 9.1.2 of the NASA/NTRC Rotorcraft Center of Excellence at Georgia Institute of Technology. iv VITA August 6, 1981 . Born - Visakhapatnam, India July 2002 . .B.E. Mechanical Engineering Regional Engineering College Suratkal, India December 2004 . M.S. Mechanical Engineering The Ohio State University Columbus, OH September 2002-present . Graduate Research Associate The Ohio State University Columbus, OH PUBLICATIONS Research Publications Saijo, T., Ganesh, B.A., Huang, A.B., Komerath, N.M., Bhattacharya, S., Pulla, D.P., Con- lisk, A.T, “Development of Unsteadiness in the Wake of a Rotor in Ground Effect”, Pro- ceedings of the American Helicopter Society Forum, Pheonix, AZ, May 2003. Pulla, D.P., Bhattacharyya, S., Conlisk, A.T., “Structure of the Rotor Wake in Ground ef- fect”, Annual meeting of the Division of Fluid Dynamics, APS, Meadowlands, NJ ,Novem- ber , 2003. Pulla, D.P., Conlisk, A.T., “The Long Time Structure of the Rotor Wake in Ground effect”, 43rd AIAA Aerospace Sciences Meeting, Reno, Nevada AIAA 2005-1408, January 10-13 2005. v Ganesh, B., Komerath, N.M., Pulla, D.P., Conlisk, A.T., “Unsteady Aerodynamics of Rotorcraft in Ground Effect”, 43rd AIAA Aerospace Sciences Meeting, Reno, Nevada AIAA 2005-1407, January 10-13 2005. Pulla, D.P., A.T.Conlisk., “The Unsteady Rotor Wake in Ground Effect”, Annual meeting of the Division of Fluid Dynamics, APS, Chicago, IL ,November , 2005. Pulla D.P., Vishwanath Godavarthy, Burgraff, O.R., Conlisk, A.T., “An Inviscid Model of the Formation of a Rotor Tip-Vortex”, accepted for publication by the AIAA Journal. FIELDS OF STUDY Major Field: Mechanical Engineering Studies in Fluid Mechanics: Professor A.T. Conlisk vi TABLE OF CONTENTS Page Abstract . ii Acknowledgments . iv Vita . v List of Tables . x List of Figures . xi Chapters: 1. Introduction . 1 1.1 Background . 1 1.2 Overview of Helicopter Aerodynamics . 3 1.3 Rotor Wake . 7 1.4 Wake Models . 9 1.5 Effect of the Ground on the Rotor Flow Field . 11 1.6 The Current Work . 16 2. Numerical Model for the Blade . 18 2.1 Introduction . 18 2.2 Lifting Line Theory . 19 2.3 Lifting Surface Model . 24 2.4 IGE Wake Model . 35 2.5 Summary . 42 vii 3. Results - Lifting Line . 46 3.1 Introduction . 46 3.2 Results - Lifting Line Theory . 47 3.2.1 OGE Hover for Comparison with IGE Results . 47 3.2.2 IGE Hover Lifting Line Results . 50 3.2.3 IGE Forward Flight - Single-Bladed Rotor Flow Field Results . 58 3.2.4 IGE Forward Flight - Two-Bladed Rotor . 64 3.2.5 Comparison with Experiments . 72 3.3 RMS Velocity Variations . 78 3.4 Summary . 92 4. Results - Lifting Surface Model . 95 4.1 Introduction . 95 4.2 Results - Lifting Surface . 96 4.2.1 Results - Single-Bladed Hover Lifting Surface . 96 4.2.2 Results - Two-Bladed Hover Lifting Surface . 100 4.2.3 Results - Single-Bladed Forward Flight Lifting surface . 101 4.2.4 Results - Two-Bladed Forward Flight Lifting Surface . 111 4.2.5 Comparison with Experiments . 115 4.3 Transient Velocity Variations . 123 4.4 Summary . 142 5. Loads . 144 5.1 Introduction . 144 5.2 Computation of Loads Using Lifting Line Theory in Hover . 146 5.3 Computation of Loads Using the Lifting Surface Theory . 154 5.4 Results - Lifting Line Theory . 156 5.4.1 Results in Hover . 156 5.4.2 Results - Forward Flight . 160 5.5 Results - Lifting Surface Theory . 162 5.5.1 Results - Hover . 163 5.5.2 Results - Forward Flight . 166 5.5.3 Comparison of Lifting Line and Lifting Surface Models . 167 5.6 Summary . 170 viii 6. Main Rotor - Tail Rotor Interactions . 171 6.1 Introduction . 171 6.2 Numerical Model . 173 6.3 Results . 174 6.3.1 Flow field . 174 6.3.2 Loads . 175 6.4 Summary . 185 7. Overview and Future Work . 187 7.1 Summary . 187 7.2 Future Work . 190 Appendices: A. Vortex Ring Computation . 192 Bibliography . 195 ix LIST OF TABLES Table Page 3.1 Experimental Parameters in Caradonna et al. [32] experiments. 50 3.2 Experimental parameters in Light [17] experiments. 50 3.3 Comparison of ground vortex coordinates in computation and experiment; h=R = 0:72, two-bladed rotor, µ = 0:03. 72 4.1 Comparison of ground vortex coordinates in computation and experiment; h=R = 0:72, two-bladed rotor, µ = 0:03. 121 4.2 Comparison of ground vortex coordinates in computations obtained using lifting surface and lifting line models; h=R = 0:72, two-bladed rotor, µ = 0:03. 123 x LIST OF FIGURES Figure Page 1.1 A summary of specific flow problems involving helicopter aerodynamics. From [1]. 4 1.2 A single bladed rotor in forward flight; a top view (a)Advancing and re- treating sides of the rotor disk. (b) Definition of lag and flap angles. (b) Lift and drag in forward flight. 6 1.3 Trailed and shed vorticity in rotor wake(Johnson [3]). 7 1.4 Sketch of a helicopter rotor wake for a single blade. From Gray [4]. 8 1.5 Comparison of partial and total ground effects. 12 2.1 Lifting line model for a fixed wing ; the dark areas indicate the magnitude of bound circulation; circulation has an elliptical distribution in the fixed wing case. 20 2.2 Velocity induced by the segments of a typical horseshoe element. 22 2.3 Horseshoe vortex model of a rotary wing. 26 2.4 Horseshoe-vortex panel implementation of a semi-infinite wing. The panel width is non-uniform in the spanwise direction, as discussed in the text. The velocity boundary condition is applied at the three-quarter chord line at the midspan point of each panel. (a) Definition of the local panel coordi- nates. (b) Definition of the global coordinates. 28 xi 2.5 Schematic of the trailing vortex system. Open circles denote the quarter- chord location of each panel (bound vortices), solid circles denote panel edges. Arrows denote the normal direction at the panel three-quarter chord line (normal-velocity boundary condition) [26]. 30 2.6 Bound circulation disribution along the blade in hover IGE, h=R = 0:5 and o OGE; A = 6, α0=10 . 32 2.7 Comparison of the dimensionless tip-vortex circulations for lifting line and lifting surface models in hover, h=R = 0:5. 33 2.8 Dimensionless tip-vortex circulation as a function of the aspect ratio in hover, h=R = 0:5.
Load more

Recommended publications
  • NASA Mars Helicopter Team Striving for a “Kitty Hawk” Moment
    NASA Mars Helicopter Team Striving for a “Kitty Hawk” Moment NASA’s next Mars exploration ground vehicle, Mars 2020 Rover, will carry along what could become the first aircraft to fly on another planet. By Richard Whittle he world altitude record for a helicopter was set on June 12, 1972, when Aérospatiale chief test pilot Jean Boulet coaxed T his company’s first SA 315 Lama to a hair-raising 12,442 m (40,820 ft) above sea level at Aérodrome d’Istres, northwest of Marseille, France. Roughly a year from now, NASA hopes to fly an electric helicopter at altitudes equivalent to two and a half times Boulet’s enduring record. But NASA’s small, unmanned machine actually will fly only about five meters above the surface where it is to take off and land — the planet Mars. Members of NASA’s Mars Helicopter team prepare the flight model (the actual vehicle going to Mars) for a test in the JPL The NASA Mars Helicopter is to make a seven-month trip to its Space Simulator on Jan. 18, 2019. (NASA photo) destination folded up and attached to the underbelly of the Mars 2020 Rover, “Perseverance,” a 10-foot-long (3 m), 9-foot-wide (2.7 The atmosphere of Mars — 95% carbon dioxide — is about one m), 7-foot-tall (2.13 m), 2,260-lb (1,025-kg) ground exploration percent as dense as the atmosphere of Earth. That makes flying at vehicle. The Rover is scheduled for launch from Cape Canaveral five meters on Mars “equal to about 100,000 feet [30,480 m] above this July on a United Launch Alliance Atlas V rocket and targeted sea level here on Earth,” noted Balaram.
    [Show full text]
  • Design, Modelling and Control of a Space UAV for Mars Exploration
    Design, Modelling and Control of a Space UAV for Mars Exploration Akash Patel Space Engineering, master's level (120 credits) 2021 Luleå University of Technology Department of Computer Science, Electrical and Space Engineering Design, Modelling and Control of a Space UAV for Mars Exploration Akash Patel Department of Computer Science, Electrical and Space Engineering Faculty of Space Science and Technology Luleå University of Technology Submitted in partial satisfaction of the requirements for the Degree of Masters in Space Science and Technology Supervisor Dr George Nikolakopoulos January 2021 Acknowledgements I would like to take this opportunity to thank my thesis supervisor Dr. George Nikolakopoulos who has laid a concrete foundation for me to learn and apply the concepts of robotics and automation for this project. I would be forever grateful to George Nikolakopoulos for believing in me and for supporting me in making this master thesis a success through tough times. I am thankful to him for putting me in loop with different personnel from the robotics group of LTU to get guidance on various topics. I would like to thank Christoforos Kanellakis for guiding me in the control part of this thesis. I would also like to thank Björn Lindquist for providing me with additional research material and for explaining low level and high level controllers for UAV. I am grateful to have been a part of the robotics group at Luleå University of Technology and I thank the members of the robotics group for their time, support and considerations for my master thesis. I would also like to thank Professor Lars-Göran Westerberg from LTU for his guidance in develop- ment of fluid simulations for this master thesis project.
    [Show full text]
  • Real-Time Helicopter Flight Control: Modelling and Control by Linearization and Neural Networks
    Purdue University Purdue e-Pubs Department of Electrical and Computer Department of Electrical and Computer Engineering Technical Reports Engineering August 1991 Real-Time Helicopter Flight Control: Modelling and Control by Linearization and Neural Networks Tobias J. Pallett Purdue University School of Electrical Engineering Shaheen Ahmad Purdue University School of Electrical Engineering Follow this and additional works at: https://docs.lib.purdue.edu/ecetr Pallett, Tobias J. and Ahmad, Shaheen, "Real-Time Helicopter Flight Control: Modelling and Control by Linearization and Neural Networks" (1991). Department of Electrical and Computer Engineering Technical Reports. Paper 317. https://docs.lib.purdue.edu/ecetr/317 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Real-Time Helicopter Flight Control: Modelling and Control by Linearization and Neural Networks Tobias J. Pallett Shaheen Ahmad TR-EE 91-35 August 1991 Real-Time Helicopter Flight Control: Modelling and Control by Lineal-ization and Neural Networks Tobias J. Pallett and Shaheen Ahmad Real-Time Robot Control Laboratory, School of Electrical Engineering, Purdue University West Lafayette, IN 47907 USA ABSTRACT In this report we determine the dynamic model of a miniature helicopter in hovering flight. Identification procedures for the nonlinear terms are also described. The model is then used to design several linearized control laws and a neural network controller. The controllers were then flight tested on a miniature helicopter flight control test bed the details of which are also presented in this report. Experimental performance of the linearized and neural network controllers are discussed.
    [Show full text]
  • Adventures in Low Disk Loading VTOL Design
    NASA/TP—2018–219981 Adventures in Low Disk Loading VTOL Design Mike Scully Ames Research Center Moffett Field, California Click here: Press F1 key (Windows) or Help key (Mac) for help September 2018 This page is required and contains approved text that cannot be changed. NASA STI Program ... in Profile Since its founding, NASA has been dedicated • CONFERENCE PUBLICATION. to the advancement of aeronautics and space Collected papers from scientific and science. The NASA scientific and technical technical conferences, symposia, seminars, information (STI) program plays a key part in or other meetings sponsored or co- helping NASA maintain this important role. sponsored by NASA. The NASA STI program operates under the • SPECIAL PUBLICATION. Scientific, auspices of the Agency Chief Information technical, or historical information from Officer. It collects, organizes, provides for NASA programs, projects, and missions, archiving, and disseminates NASA’s STI. The often concerned with subjects having NASA STI program provides access to the NTRS substantial public interest. Registered and its public interface, the NASA Technical Reports Server, thus providing one of • TECHNICAL TRANSLATION. the largest collections of aeronautical and space English-language translations of foreign science STI in the world. Results are published in scientific and technical material pertinent to both non-NASA channels and by NASA in the NASA’s mission. NASA STI Report Series, which includes the following report types: Specialized services also include organizing and publishing research results, distributing • TECHNICAL PUBLICATION. Reports of specialized research announcements and feeds, completed research or a major significant providing information desk and personal search phase of research that present the results of support, and enabling data exchange services.
    [Show full text]
  • Micro Coaxial Helicopter Controller Design
    Micro Coaxial Helicopter Controller Design A Thesis Submitted to the Faculty of Drexel University by Zelimir Husnic in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2014 c Copyright 2014 Zelimir Husnic. All Rights Reserved. ii Dedications To my parents and family. iii Acknowledgments There are many people who need to be acknowledged for their involvement in this research and their support for many years. I would like to dedicate my thankfulness to Dr. Bor-Chin Chang, without whom this work would not have started. As an excellent academic advisor, he has always been a helpful and inspiring mentor. Dr. B. C. Chang provided me with guidance and direction. Special thanks goes to Dr. Mishah Salman and Dr. Humayun Kabir for their mentorship and help. I would like to convey thanks to my entire thesis committee: Dr. Chang, Dr. Kwatny, Dr. Yousuff, Dr. Zhou and Dr. Kabir. Above all, I express my sincere thanks to my family for their unconditional love and support. iv v Table of Contents List of Tables ........................................... viii List of Figures .......................................... ix Abstract .............................................. xiii 1. Introduction .......................................... 1 1.1 Vehicles to be Discussed................................... 1 1.2 Coaxial Benefits ....................................... 2 1.3 Motivation .......................................... 3 2. Helicopter Flight Dynamics ................................ 4 2.1 Introduction ........................................
    [Show full text]
  • Over Thirty Years After the Wright Brothers
    ver thirty years after the Wright Brothers absolutely right in terms of a so-called “pure” helicop- attained powered, heavier-than-air, fixed-wing ter. However, the quest for speed in rotary-wing flight Oflight in the United States, Germany astounded drove designers to consider another option: the com- the world in 1936 with demonstrations of the vertical pound helicopter. flight capabilities of the side-by-side rotor Focke Fw 61, The definition of a “compound helicopter” is open to which eclipsed all previous attempts at controlled verti- debate (see sidebar). Although many contend that aug- cal flight. However, even its overall performance was mented forward propulsion is all that is necessary to modest, particularly with regards to forward speed. Even place a helicopter in the “compound” category, others after Igor Sikorsky perfected the now-classic configura- insist that it need only possess some form of augment- tion of a large single main rotor and a smaller anti- ed lift, or that it must have both. Focusing on what torque tail rotor a few years later, speed was still limited could be called “propulsive compounds,” the following in comparison to that of the helicopter’s fixed-wing pages provide a broad overview of the different helicop- brethren. Although Sikorsky’s basic design withstood ters that have been flown over the years with some sort the test of time and became the dominant helicopter of auxiliary propulsion unit: one or more propellers or configuration worldwide (approximately 95% today), jet engines. This survey also gives a brief look at the all helicopters currently in service suffer from one pri- ways in which different manufacturers have chosen to mary limitation: the inability to achieve forward speeds approach the problem of increased forward speed while much greater than 200 kt (230 mph).
    [Show full text]
  • Development of a Helicopter Vortex Ring State Warning System Through a Moving Map Display Computer
    Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection 1999-09 Development of a helicopter vortex ring state warning system through a moving map display computer Varnes, David J. Monterey, California. Naval Postgraduate School http://hdl.handle.net/10945/26475 DUDLEY KNOX LIBRARY NAVAL POSTGRADUATE SCHOOL MONTEREY CA 93943-5101 NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS DEVELOPMENT OF A HELICOPTER VORTEX RING STATE WARNING SYSTEM THROUGH A MOVING MAP DISPLAY COMPUTER by David J. Varnes September 1999 Thesis Advisor: Russell W. Duren Approved for public release; distribution is unlimited. Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington. VA 22202-4302, and to the Office of Management and Budget. Paperwork Reduction Project (0704-0188) Washington DC 20503. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 1. agency use only (Leave blank) September 1999 Master's Thesis 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS DEVELOPMENT OF A HELICOPTER VORTEX RING STATE WARNING SYSTEM THROUGH A MOVING MAP DISPLAY COMPUTER 6. AUTHOR(S) Varnes, David, J. 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) PERFORMING ORGANIZATION Naval Postgraduate School REPORT NUMBER Monterey, CA 93943-5000 10.
    [Show full text]
  • HELICOPTER SAFETY Vol
    F L I G H T S A F E T Y F O U N D A T I O N HELICOPTER SAFETY Vol. 16 No. 6 For Everyone Concerned with the Safety of Flight November/December 1990 Inflight Icing and the Helicopter Results of a U.S. Army investigation into the unique hazards facing rotary wing operations in the winter environment offers timely tips for all helicopter flight crews. Traditionally, helicopter operating manuals have addressed of fixed-wing flight. Typically, we have characterized the issue of inflight icing and its effect on helicopter icing problems by their effect on lift, drag, weight and performance with a caution or a warning to the pilot to thrust. It is readily accepted that inflight icing reduces avoid an icing environment. Such restrictions and limita- thrust and lift, and increases drag and weight, all to the tions were acceptable when helicopters were viewed as detriment of aircraft performance. aircraft operating primarily in visual meteorological con- ditions (VMC). Since early helicopters lacked the equip- Rotary-wing aircraft also suffer from these effects when ment and sophisticated systems normally employed for exposed to icing conditions and, in addition, are suscep- flight in instrument meteorological conditions (IMC), there tible to various complications that are not common to was little justification for expending valuable time and fixed-wing aircraft. Although many questions remain resources on helicopter icing research and development. regarding helicopter icing and its impact on aircraft per- formance and mission effectiveness, researchers are un- However, modern helicopters have a greatly expanded covering significant insights into this facet of helicopter concept of operations and today they routinely perform a development.
    [Show full text]
  • The Pennsylvania State University the Graduate School Department of Aerospace Engineering an INVESTIGATION of PERFORMANCE BENEFI
    The Pennsylvania State University The Graduate School Department of Aerospace Engineering AN INVESTIGATION OF PERFORMANCE BENEFITS AND TRIM REQUIREMENTS OF A VARIABLE SPEED HELICOPTER ROTOR A Thesis in Aerospace Engineering by Jason H. Steiner 2008 Jason H. Steiner Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science August 2008 ii The thesis of Jason Steiner was reviewed and approved* by the following: Farhan Gandhi Professor of Aerospace Engineering Thesis Advisor Robert Bill Research Associate , Department of Aerospace Engineering George Leisuietre Professor of Aerospace Engineering Head of the Department of Aerospace Engineering *Signatures are on file in the Graduate School iii ABSTRACT This study primarily examines the main rotor power reductions possible through variation in rotor RPM. Simulations were based on the UH-60 Blackhawk helicopter, and emphasis was placed on possible improvements when RPM variations were limited to ± 15% of the nominal rotor speed, as such limited variations are realizable through engine speed control. The studies were performed over the complete airspeed range, from sea level up to altitudes up to 12,000 ft, and for low, moderate and high vehicle gross weight. For low altitude and low to moderate gross weight, 17-18% reductions in main rotor power were observed through rotor RPM reduction. Reducing the RPM increases rotor collective and decreases the stall margin. Thus, at higher airspeeds and altitudes, the optimal reductions in rotor speed are smaller, as are the power savings. The primary method for power reduction with decreasing rotor speed is a decrease in profile power. When rotor speed is optimized based on both power and rotor torque, the optimal rotor speed increases at low speeds to decrease rotor torque without power penalties.
    [Show full text]
  • The Pennsylvania State University
    The Pennsylvania State University The Graduate School Department of Aerospace Engineering REAL-TIME PATH PLANNING AND AUTONOMOUS CONTROL FOR HELICOPTER AUTOROTATION A Dissertation in Aerospace Engineering by Thanan Yomchinda 2013 Thanan Yomchinda Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2013 The dissertation of Thanan Yomchinda was reviewed and approved* by the following: Joseph F. Horn Associate Professor of Aerospace Engineering Dissertation Co-Advisor Co-Chair of Committee Jacob W. Langelaan Associate Professor of Aerospace Engineering Dissertation Co-Advisor Co-Chair of Committee Edward C. Smith Professor of Aerospace Engineering Christopher D. Rahn Professor of Mechanical Engineering George A. Lesieutre Professor of Aerospace Engineering Head of the Department of Aerospace Engineering *Signatures are on file in the Graduate School iii ABSTRACT Autorotation is a descending maneuver that can be used to recover helicopters in the event of total loss of engine power; however it is an extremely difficult and complex maneuver. The objective of this work is to develop a real-time system which provides full autonomous control for autorotation landing of helicopters. The work includes the development of an autorotation path planning method and integration of the path planner with a primary flight control system. The trajectory is divided into three parts: entry, descent and flare. Three different optimization algorithms are used to generate trajectories for each of these segments. The primary flight control is designed using a linear dynamic inversion control scheme, and a path following control law is developed to track the autorotation trajectories. Details of the path planning algorithm, trajectory following control law, and autonomous autorotation system implementation are presented.
    [Show full text]
  • Mars Science Helicopter: Conceptual Design of the Next Generation of Mars Rotorcraft
    Mars Science Helicopter: Conceptual Design of the Next Generation of Mars Rotorcraft Shannah Withrow-Maser1 Wayne Johnson2 Larry Young 3 Witold Koning4 Winnie Kuang4 Carlos Malpica4 Ames Research Center, Moffett Field, CA, 94035 J. Balaram5 Theodore Tzanetos5 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109 Robotic planetary aerial vehicles increase the range of terrain that can be examined, compared to traditional landers and rovers, and have more near-surface capability than orbiters. Aerial mobility is a promising possibility for planetary exploration as it reduces the challenges that difficult obstacles pose to ground vehicles. The first use of a rotorcraft for a planetary mission will be in 2021, when the Ingenuity Mars helicopter technology demonstrator will be deployed via the Perseverance rover. NASA’s Jet Propulsion Laboratory and NASA Ames Research Center are exploring possibilities for a Mars Science Helicopter, a second-generation Mars rotorcraft with the capability of conducting science investigations independently of a lander or rover (although this type of vehicle could also be used to assist rovers or landers in future missions). Two, large rotorcraft configurations are described: a hexacopter and a co-axial helicopter with a payload in the range of two to three kilograms and an overall vehicle mass of approximately twenty kilograms. Additionally, advancements in technology over the course of the study are applied to a rotorcraft of the same size and form as Ingenuity. Initial estimates of weight and performance were based on the capabilities of Ingenuity. Rotorcraft designs for Mars are constrained by the dimensions of the aeroshell and lander for the trip to the planet, constraining maximum rotor dimensions and, hence, overall performance potential.
    [Show full text]
  • Aerodynamic Concept of the Uav in the Gyrodyne Configuration
    TRANSACTIONS OF THE INSTITUTE OF AVIATION 1 (250) 2018, pp. 49–66 DOI: 10.2478/tar-2018-0005 © Copyright by Wydawnictwa Naukowe Instytutu Lotnictwa AERODYNAMIC CONCEPT OF THE UAV IN THE GYRODYNE CONFIGURATION Jan Muchowski*, Marek Szumski*, Andrzej Krzysiak** *Department of Fluid Mechanics and Aerodynamics, Mechanical Engineering and Aeronautics, Rzeszow University of Technology, al. Powstańców Warszawy 8, 35-959 Rzeszow **Aerodynamics Department, Institute of Aviation, Al. Krakowska 110/114, 02-256 Warsaw [email protected], [email protected], [email protected], Abstract The article presents an aerodynamic concept of UAV in the gyrodyne configuration, as a more efficient one than the currently used UAV airframe configuration applied for monitoring tasks of pow- er lines and railway infrastructure. A sample task which is realised by conceptual gyrodyne based on monitoring aerial power lines was characterised and described . The assumed idea of UAV was shown in comparison to the currently used aircraft configuration presented in the introduction. Referring to momentum theory, hover efficiency of the multicopter and the helicopter was evaluated. In relation to the helicopter, an initial draft of the airframe conception accompanied by a description of advan- tages of the gyrodyne configuration was exposed. Problems related to the gyrodyne configuration were emphasised in the summary. Keywords: aerodynamic concept, UAV, VTOL, gyrodyne, airframe configuration 1. INTRODUCTION In recent years a dynamic growth of the UAV (Unmanned Aerial Vehicle) usage in civil and mili- tary missions can be observed . Economic aspects are the main reasons of that increase, i.e. the purchas- ing cost of the UAS (Unmanned Aircraft System) varies from 40% up to 80% of the manned system cost.
    [Show full text]