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Stability And Control Flight Testing Of A Modified Cessna 172, Tatiana Dirrigl Forbes

Theses and Dissertations

The Cessna 172N is a small, fixed-wing, single-engine aircraft. The modified Cessna 172N included a swapped engine to a Lycoming O-360-A4M, tuned exhaust, and variable timing ignition installed. Test flights on this aircraft were performed order to evaluate the stability and control characteristics of the Cessna 172N, and compare them with the regulations in the Title 14 CFR Part 23 Airworthiness Standards for Normal, Utility, Acrobatic, and Commuter Category Airplanes. The flight test consisted of four separate tests performed during a single flight, departing from and returning to Melbourne Orlando International airport (KMLB). The data was collected through static and …

Reuse Considerations For Successful Complex Systems Integration, Logan Grumbach

Dissertations

As systems have become increasingly complex, engineers are relying on reuse of components and subsystems as a method to curb complexity. However, integrating these reuse components and subsystems have historically often resulted in catastrophic failures. Technical principles key to integration success and the role of reuse in these principles are not currently defined. The objective of this research is to, first, derive and validate a set of technical integration principles and subsequently to explore how incorporating reuse impacts integration success. This research uses historical system integration data and a combination of qualitative analysis techniques and quantitative techniques to draw conclusions …

Creation Of A Trimmed Powered Aerodynamic Database For A Generic Hypersonic Vehicle, Cannon Debardelaben

Masters Theses and Doctoral Dissertations

The purpose of this thesis is to propose and evaluate a methodology for creating an inviscid trimmed powered database for a generic airbreathing hypersonic vehicle. The database was created using the cartesian flow solver Cart3D. Propulsion effects were coupled to the airframe and inlet by using conditions at the inlet of the combustor to determine conditions at the exit of the combustor. This was done by solving the quasi-one-dimensional momentum equation with heat addition. Selected trajectory points were also evaluated using the viscous solver, FUN3D. The viscous solutions contain effects such as boundary layer separation which had a pronounced effect …

Sources Of Quality Uncertainty In Laser Powder Bed Fusion Metal Additive Manufacturing, Zachary Young

Doctoral Dissertations

"Powder based additive manufacturing (AM) exhibits tremendous uncertainties, where variations in build quality is present despite utilizing similar build processing parameters. First, this work reports the features and formation mechanisms of five unique types of spatter during the LPBF process by in-situ high-speed, high-energy x-ray imaging. The unique physical characteristics of spatter are determined. The effect of laser scan speed and laser power on spatter formation, ejection, and mitigation are determined. Second, this work addresses the uncertainty challenge by identifying the sources of uncertainty in SLM by in-situ characterization due to variations from the additive manufacturing processing parameters needed for …

Nuclear Thermal Rocket Engine With A Toroidal Aerospike Nozzle, Kyle Stewart

Master's Theses

This thesis describes the coupling of a nuclear thermal rocket engine with a toroidal aerospike nozzle. The coupling of the two systems consists of two phases. The first of these phases begin with top-level systems and subsystems analysis and design of the new engine. The second phase is the analysis and characterization of the major engine systems through the use of computational fluid dynamics analysis. With the coupling of the nuclear thermal rocket engine with the aerospike nozzle, the new system will be known as the Nuclear Thermal Propulsion System. Due to the uniqueness of coupling a nuclear thermal rocket …

Environmental Life Cycle Assessment Of Commercial Space Transportation Activities In The United States, Shelia Scott Neumann

Civil Engineering Dissertations

The Commercial Space Transportation (CST) activities in the United States are increasing and have increased over 50% in the last year. The launches in the United States for commercial purposes are expected to increase another 50% in the next 3-5 years. National Environmental Policy Act (NEPA) environmental assessments do provide the regulatory environmental analysis for launching space vehicles within the United States. However, the environmental impacts from these launches have not been fully characterized. One method to characterize environmental impacts from a system is through conducting a Life Cycle Assessment (LCA) based on an international standard, ISO14040. The results from …

Experimental Study Of Global Luminescent Oil-Film (Glof) Skin-Friction Meter On Delta Wings, Patrick Nicholas Wewengkang

Masters Theses

This thesis describes how the Global Luminescent Oil-Film (GLOF) Skin-Friction Meter can be applied experimentally to extract skin-friction from a set of images. In this study, the effect of oil viscosity, experimental sample size, and step size were considered to see how they would affect the extracted skin-friction using the GLOF method. These results were then compared to published literature on skin-friction diagnostics of delta wings, based on observations of critical characteristics such as reattachment and separation lines. Delta wings of 50°, 55°, 60°, 65°, and 70° sweep angles were built and placed in the Small Wind Tunnel (SWT) at …

Simulated Annealing-Based Optimal Proportional-Integral-Derivative (Pid) Controller Design: A Case Study On Nonlinear Quadcopter Dynamics, Kristofer Kevin Nemirsky

Master's Theses

In this thesis, the history and evolution of rotor aircraft with simulated annealing-based PID application were reviewed and quadcopter dynamics are presented. The dynamics of a quadcopter were then modeled, analyzed, and linearized. A cascaded loop architecture with PID controllers was used to stabilize the plant dynamics, which was improved upon through the application of simulated annealing (SA). A Simulink model was developed to test the controllers and verify the functionality of the proposed control system design. In addition, the data that the Simulink model provided were compared with flight data to present the validity of derived dynamics as a …

A Parallel Processing And Diversified-Hidden-Gene-Based Genetic Algorithm Framework For Fuel-Optimal Trajectory Design For Interplanetary Spacecraft Missions, Dhathri Harsha Somavarapu

Master's Theses

This thesis proposes a new parallel computing genetic algorithm framework for designing fuel-optimal trajectories for interplanetary spacecraft missions. The framework can capture the deep search space of the problem with the use of a fixed chromosome structure and hidden-genes concept, can explore the diverse set of candidate solutions with the use of the adaptive and twin-space crowding techniques and, can execute on any high-performance computing (HPC) platform with the adoption of the portable message passing interface (MPI) standard. The algorithm is implemented in C++ with the use of the MPICH implementation of the MPI standard. The algorithm uses a patched-conic …

Complex Multidisciplinary System Composition For Aerospace Vehicle Conceptual Design, Alexis R. Gonzalez

Mechanical and Aerospace Engineering Dissertations

Although, there exists a vast amount of work concerning the analysis, design, integration of aerospace vehicle systems, there is no standard for how this data and knowledge should be combined in order to create a synthesis system. Each institution creating a synthesis system has in house vehicle and hardware components they are attempting to model and proprietary methods with which to model them. This leads to the fact that synthesis systems begin as one-off creations meant to answer a specific problem. As the scope of the synthesis system grows to encompass more and more problems, so does its size and …

A Usability And Learnability Case Study Of Glass Flight Deck Interfaces And Pilot Interactions Through Scenario-Based Training, Thomas James De Cino

CCE Theses and Dissertations

In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems.

While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks …

A Study Of Laser Ablation Propulsion Using Polyoxymethelyne And A High Power Diode Laser, Michael David Kolesar

Master's Theses

With an increased interest by universities, government and commercial groups in using constellations of pico and and nano satellites, the need for micro-thrusters to aid in the station-keeping capabilities has become strong. This report examines using polymers and a laser to ablate material as a potential propulsion option for station-keeping. Homopolymer polyoxymethelyne (POM), commonly known as Delrin™, was tested as a fuel for a high powered (20 Watt 980 nm) solid state diode laser ablation thruster to be used for station-keeping on pico and nano sized satellites. The experiments required a partial vacuum to reduce the effects of air decomposition …

Design Of An Attitude Control System For Spin-Axis Control Of A 3u Cubesat, Alexander Joseph Westfall

Master's Theses

This paper describes the design process of developing a spin-axis control system for a 3U CubeSat, a relatively small satellite. Design requires the CubeSat to de-spin after deployment and direct its antenna to track Earth nadir position. The one degree of freedom controller is developed for the TechEdSat, which is a CubeSat with a payload that allows for the assumption that rotation pitch and yaw rates are sufficiently close to zero. Satellite torqueing disturbances are modeled with reaction wheel noise for a more complete system analysis. Sensor noise is unmodeled. Frequency domain and time domain analyses are presented; the entire …

Implementing A Linear Quadratic Spacecraft Attitude Control System, Daniel Kolosa

Masters Theses

This thesis implements a linear quadratic attitude control system for a low-thrust spacecraft. The goal is to maintain spacecraft alignment with a time-varying thrust vector needed for trajectory change maneuvers. A linear quadratic attitude control approach is used to maintain spacecraft pointing throughout flight. This attitude control strategy uses the thrust-acceleration input obtained from a linear quadratic optimal trajectory control model that simulates the trajectory of a spacecraft in orbit maneuvers. This attitude model simulates a CubeSat, a small satellite that is equipped with a low-thrust propulsion and attitude control system. An orbit raising and a plane change scenario is …

Utilization Of Differential Thrust For Lateral/Directional Stability Of A Commercial Aircraft With A Damaged Vertical Stabilizer, Long Lu

Master's Theses

This thesis investigates the utilization of differential thrust to help a

commercial aircraft with a damaged vertical stabilizer regain its lateral/directional

stability. In the event of an aircraft losing its vertical stabilizer, the consequential

loss of the lateral/directional stability is likely to cause a fatal crash. In this thesis,

the damaged aircraft model is constructed, and the lateral/directional dynamic

stability and frequency domain analyses are conducted. The propulsion dynamics of

the aircraft are modeled as a system of differential equations with engine time

constant and time delay terms to study the engine response time with respect to a

differential thrust …

Numerical Investigation Of The Influence Of Elevated Turbulence Levels On The Cooling Effectiveness Of An Anti-Vortex Hole Geometry, Timothy William Repko

Graduate Theses, Dissertations, and Problem Reports

A novel film cooling hole geometry for use in gas turbine engines has been investigated numerically by solving the Reynolds Averaged Navier-Stokes equations in a commercial CFD code (STAR-CCM+) with varying turbulence intensity and length scale using the k-o SST turbulence model. Both steady and unsteady results were considered in order to investigate the effects of freestream turbulence intensity and length scale on this novel anti-vortex hole (AVH) concept. The AVH geometry utilizes two side holes, one on each side of the main hole, to attempt to mitigate the vorticity from the jet from the main hole. The AVH concept …

Development Of The West Virginia University Small Microgravity Research Facility (Wvu Smirf), Kyle G. Phillips

Graduate Theses, Dissertations, and Problem Reports

West Virginia University (WVU) has created the Small Microgravity Research Facility (SMiRF) drop tower through a WVU Research Corporation Program to Stimulate Competitive Research (PSCoR) grant on its campus to increase direct access to inexpensive and repeatable reduced gravity research. In short, a drop tower is a tall structure from which experimental payloads are dropped, in a controlled environment, and experience reduced gravity or microgravity (i.e. "weightlessness") during free fall. Currently, there are several methods for conducting scientific research in microgravity including drop towers, parabolic flights, sounding rockets, suborbital flights, NanoSats, CubeSats, full-sized satellites, manned orbital flight, and the International …

Aircraft Abnormal Conditions Detection, Identification, And Evaluation Using Innate And Adaptive Immune Systems Interaction, Dia Al Azzawi

Graduate Theses, Dissertations, and Problem Reports

Abnormal flight conditions play a major role in aircraft accidents frequently causing loss of control. To ensure aircraft operation safety in all situations, intelligent system monitoring and adaptation must rely on accurately detecting the presence of abnormal conditions as soon as they take place, identifying their root cause(s), estimating their nature and severity, and predicting their impact on the flight envelope.;Due to the complexity and multidimensionality of the aircraft system under abnormal conditions, these requirements are extremely difficult to satisfy using existing analytical and/or statistical approaches. Moreover, current methodologies have addressed only isolated classes of abnormal conditions and a reduced …

A Force Sensor Array For Space Applications, Timothy L. Weadon

Graduate Theses, Dissertations, and Problem Reports

The need for force feedback and spatial awareness of contact in harsh environment applications, such as space servicing, has been unsatisfied due to the inability of current sensor technology to resist environmental effects. In this work, capacitive sensors based on a porous polymer-ceramic composite structure were evaluated for potential use in future operations within robotic end-effectors, withstanding temperatures ranging from -80 °C to 120 °C and forces up to 350 kPa. A thin-film design is utilized to allow for ease of embedding, allowing sensors to be implemented into exciting robotic hardware with minimal intrusion, and protecting sensors from electron bombardment, …

Prediction Of Residual Stress And Distortion From Residual Stress In Heat Treated And Machined Aluminum Parts, Robert Michael Jones

Master's Theses

Parts machined from relatively large thickness cross sections can experience significant deformations from high residual stresses that develop in the part during the heat treatment used to form the aluminum alloy. Uphill quenching is a process that can create a part with low residual stress and stable dimensions when the process is controlled properly. The uphill quenching process involves a solution heat treat, quench, cool to liquid nitrogen, steam blast, and then age to final temper.

In this thesis two parts were modeled using ANSYS. The first part underwent the uphill quench process in the rough machined state. The second …

Numerical And Experimental Study On The Ability Of Dynamic Roughness To Alter The Development Of A Leading Edge Vortex, Christopher D. Griffin

Graduate Theses, Dissertations, and Problem Reports

Dynamic stall is an unsteady aerodynamic phenomenon garnering much research interest because it occurs in a variety of applications. For example, dynamic stall is known to occur on helicopter rotor blades, wind turbines, high maneuvering military aircraft, and flapping wings. Dynamic stall occurs when an aerodynamic lifting device, such as an airfoil, wing, or turbomachine blade, undergoes a rapid pitching motion. It also occurs on lifting devices that are impulsively started at high angles of attack. Dynamic stall can "delay" aerodynamic stall to angles of attack that are significantly beyond the static stall angle of attack.;During dynamic stall a large …

Machine-Vision-Based Pose Estimation System Using Sensor Fusion For Autonomous Satellite Grappling, Andres Felipe Velasquez Escandon

Graduate Theses, Dissertations, and Problem Reports

When capturing a non-cooperative satellite during an on-orbit satellite servicing mission, the position and orientation (pose) of the satellite with respect to the servicing vessel is required in order to guide the robotic arm of the vessel towards the satellite. The main objective of this research is the development of a machine vision-based pose estimation system for capturing a non-cooperative satellite. The proposed system finds the satellite pose using three types of natural geometric features: circles, lines and points, and it merges data from two monocular cameras and three different algorithms (one for each type of geometric feature) to increase …

Folding Solid-Membrane Wing Structure For A Micro Air Vehicle, Joe D. Allen Jr.

Graduate Theses, Dissertations, and Problem Reports

The design of a solid-membrane folding wing for use on a tube launched micro air vehicle (MAV), and experimental wind tunnel results of the wing integrated on an engineering MAV model are presented herein. Due to the sizing and performance requirements of the MAV, the wing must provide sufficient wing area while minimizing its stowed footprint. Many current available methods for folding the wing for such a MAV sacrifice aerodynamic efficiency or are cost prohibitive. The solid-membrane wing design presented blends elements of a solid semi-rigid wing with those of a membrane wing. This provides the aerodynamic efficiency of a …

Wind And Wake Sensing With Uav Formation Flight: System Development And Flight Testing, Trenton Jameson Larrabee

Graduate Theses, Dissertations, and Problem Reports

Wind turbulence including atmospheric turbulence and wake turbulence have been widely investigated; however, only recently it become possible to use Unmanned Aerial Vehicles (UAVs) as a validation tool for research in this area. Wind can be a major contributing factor of adverse weather for aircraft. More importantly, it is an even greater risk towards UAVs because of their small size and weight. Being able to estimate wind fields and gusts can potentially provide substantial benefits for both unmanned and manned aviation. Possible applications include gust suppression for improving handling qualities, a better warning system for high wind encounters, and enhanced …

Aerodynamic Parameter Identification Of A Venus Lander, Robert A. Sykes

Graduate Theses, Dissertations, and Problem Reports

An analysis was conducted to identify the parameters of an aerodynamic model for a Venus lander based on experimental free-flight data. The experimental free-flight data were collected in the NASA Langley 20-ft Vertical Spin Tunnel with a 25-percent Froude-scaled model. The experimental data were classified based on the wind tunnel run type: runs where the lander model was unperturbed over the course of the run, and runs were the model was perturbed (principally in pitch, yaw, and roll) by the wind tunnel operator. The perturbations allow for data to be obtained at higher wind angles and rotation rates than those …

Droplet Impact Sub-Cavity Histories And Pdpa Spray Experiments For Spray Cooling Modeling, Nicholas Lee Hillen

Graduate Theses, Dissertations, and Problem Reports

Spray cooling is a topic of current interest for its ability to uniformly remove high levels of waste heat from densely packed microelectronics. It has demonstrated the ability to achieve very high heat fluxes, up to 500 W/cm2 with water as the coolant, making it an attractive active thermal management tool.;Full Computational Fluid Dynamic (CFD) simulations of spray cooling are infeasible due to the complexity of the spray (drops fluxes of 106 drops/cm2-sec) and heater surface physics requiring impractical resources. Thus a Monte-Carlo (MC) spray cooling simulation model based on empirical data is under development to serve as a cost …

Sensitivity And Stability Analysis Of Nonlinear Kalman Filters With Application To Aircraft Attitude Estimation, Matthew Brandon Rhudy

Graduate Theses, Dissertations, and Problem Reports

No abstract provided.

Development Of An Integrated Intelligent Multi -Objective Framework For Uav Trajectory Generation, Jennifer Nicole Wilburn

Graduate Theses, Dissertations, and Problem Reports

This thesis explores a variety of path planning and trajectory generation schemes intended for small, fixed-wing Unmanned Aerial Vehicles. Throughout this analysis, discrete and pose-based methods are investigated. Pose-based methods are the focus of this research due to their increased flexibility and typically lower computational overhead.;Path planning in 3 dimensions is also performed. The 3D Dubins methodology presented is an extension of a previously suggested approach and addresses both the mathematical formulation of the methodology, as well as an assessment of numerical issues encountered and the solutions implemented for these.;The main contribution of this thesis is a 3-dimensional clothoid trajectory …

The Characterization Of Wing-Wing Vortex Interactions Of A Tandem Flapping Wing Configuration And Its Relationship To The Phase Angle And Wing Spacing., Timothy Michael Broering 1985-

Electronic Theses and Dissertations

A number of flying insects make use of tandem wing configurations, suggesting that such a setup may have potential advantages over a single wing at low Reynolds numbers. Dragonflies, which are fast and highly maneuverable, demonstrate well, the potential performance of such a configuration. In a tandem wing configuration, the hindwing often operates in the wake of the forewing and, hence, its performance is affected by the vortices shed by the forewing. Changes in the phase angle between the flapping motions of the fore and hind wings, as well as the spacing between them, can affect the resulting vortex/wing and …

Titan I Propulsion System Modeling And Possible Performance Improvements, Oreste Giusti

Master's Theses

This thesis features the Titan I propulsion systems and offers data-supported suggestions for improvements to increase performance. The original propulsion systems were modeled both graphically in CAD and via equations. Due to the limited availability of published information, it was necessary to create a more detailed, secondary set of models. Various engineering equations--pertinent to rocket engine design--were implemented in order to generate the desired extra detail. This study describes how these new models were then imported into the ESI CFD Suite. Various parameters are applied to these imported models as inputs that include, for example, bi-propellant combinations, pressure, temperatures, and …