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Theses and Dissertations

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Full-Text Articles in Aerospace Engineering

Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft, Austin Lawrence Andwan Dec 2022

Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft, Austin Lawrence Andwan

Theses and Dissertations

Electric aircraft are on the horizon. Both industry and regulators have an abundance of flight tests ahead to ensure safe operation of these new aircraft. Conventional performance standards regaurding edurance, climb performance and cruise conditions are largely not applicable to assessing an electrically propulsed aircraft. While battery technologies are the current barrier for electric aircraft, there also hasn’t been much flight testing to reveal their unique performance trends. This experiment focus’s on characterizing some of these performance trends obtained through a level flight and climb test in the Pipistrel Velis Electro. The rate-of-climb did not exhibit a decrease when the …


Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther Dec 2022

Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther

Theses and Dissertations

This document finds the stability and control affects of electric powerplant conversion on a pre-existing internal combustion powered Pipistrel Virus SW through comparison with the Pipistrel Velis Electro. Testing included analysis of both static and dynamic stability on the longitudinal and lateral-directional axes of the airplane. Due to the light sport airplane being used in testing, some of the intedended tests were unable to be performed, however, conclusions were still capable of being made. The primary conclusion is that electric conversion of an airframe has no significant negative consequences, with the airplane still exhibiting positive stability on all three axes. …


Piper Pa-28-181 Archer Iii Tail #931ec Flight Test Stability, Control And Performance, Steven Allan Sutton Dec 2022

Piper Pa-28-181 Archer Iii Tail #931ec Flight Test Stability, Control And Performance, Steven Allan Sutton

Theses and Dissertations

The following flight test was conducted as part of the culmination requirement for the Master of Science, Flight Test Engineer degree program from Florida Institute of Technology. The flight was conducted to gather data and produce a flight test report on the data gathered. The flight test plan consisted of a series of both Stability and Handling test point as well as basic aircraft performance points. The testing was planned to be accomplished over a single flight, for reasons discussed later in this report. The flight departed on the morning of 26 September, 2022 out of Bob Sikes Airport, KCEW, …


Analysis Of Propeller Designs Focusing On Lowering Sound Pressure Level Through Reduced Tip Loading, Luca A. Zeitvogel Dec 2022

Analysis Of Propeller Designs Focusing On Lowering Sound Pressure Level Through Reduced Tip Loading, Luca A. Zeitvogel

Theses and Dissertations

This research focused on potential design optimizations for small propellers. Designs sought to reduce noise generated without sacrificing efficiency by “unloading” the propeller tip by reducing angle of attack near the tip. To see if nearfield performance improvements translated to a reduction in farfield sound pressure level, farfield experimental acoustic testing was performed on propellers that had been measured experimentally in the nearfield. The farfield results provided limited insight due to an equipment malfunction during testing. However, a large data set was obtained, which provides opportunities for future analyses. A computational simulation sought to recreate some of the nearfield experiments …


Developmental Evaluation Of The B-1b Aircraft, Jonathon Malycke Dec 2022

Developmental Evaluation Of The B-1b Aircraft, Jonathon Malycke

Theses and Dissertations

The purpose of this test was to perform a Developmental Phase IIA evaluation of the B-1B Lancer for the land-based, long-range, all-weather ground attack mission. One two-hour ground evaluation, one simulator and one flight totaling 7.5 hours was conducted under daylight, visual meteorological conditions from Dyess Air Force Base (AFB) in Abilene, Texas (337th Test and Evaluation Squadron). All test objectives were completed except the low altitude flight evaluation, landing pattern operations, and AFCS operations due to weather, maintenance and time constraints. The test aircraft was representative of a production B-1B aircraft and included a Sniper Targeting Pod and a …


Digital Twins In Advanced Manufacturing To Enhance Manufacturing Efficiency, Max Kirkpatrick Oct 2022

Digital Twins In Advanced Manufacturing To Enhance Manufacturing Efficiency, Max Kirkpatrick

Theses and Dissertations

Digital Twins of manufacturing systems are an emerging tool for improvement, optimization, and monitoring of physical manufacturing systems. The idea of representing physical systems with digital depictions has been prevalent since the early days of Computer Aided Design (CAD), but recently the concept of a Digital Twin has been expanded to encapsulate more than just a digital model of a design. Instead, the Digital Twin offers a unique, comprehensive, and real-time toolset for analysis and improvement of physical systems. These tools can be used to improve system efficiency, perform “what-if” analyses, virtually commission manufacturing equipment, analyze system performance in real …


A Machine Learning Framework For Automatic Speech Recognition In Air Traffic Control Using Word Level Binary Classification And Transcription, Fowad Shahid Sohail Sep 2022

A Machine Learning Framework For Automatic Speech Recognition In Air Traffic Control Using Word Level Binary Classification And Transcription, Fowad Shahid Sohail

Theses and Dissertations

Advances in Artificial Intelligence and Machine learning have enabled a variety of new technologies. One such technology is Automatic Speech Recognition (ASR), where a machine is given audio and transcribes the words that were spoken. ASR can be applied in a variety of domains to improve general usability and safety. One such domain is Air Traffic Control (ATC). ASR in ATC promises to improve safety in a mission critical environment. ASR models have historically required a large amount of clean training data. ATC environments are noisy and acquiring labeled data is a difficult, expertise dependent task. This thesis attempts to …


Additive Manufacturing Of Molybdenum For High Temperature Structural Applications, Megan L. Bustin Sep 2022

Additive Manufacturing Of Molybdenum For High Temperature Structural Applications, Megan L. Bustin

Theses and Dissertations

This research considered additive manufactured (AM) molybdenum (Mo) and the effect of three variables on microstructure, mechanical properties, and the relationship between the two. Test temperature, laser speed, and shield gas or build atmosphere were varied, and samples tested and analyzed using a three-point bending test, chemical composition, and optical and scanning electron microscopy. The relationship among variables and results using a Design of Experiments was limited compared to the inclusion of every tested sample. Most effects were expected: samples tested at room temperature were brittle without statistical significance; increasing laser speed resulted in decreased ductility and strain, smaller grain …


Finite Fatigue Life Prediction Of Additively Manufactured Aircraft Engine Turbine Blade With Respect To Internal Defect Size And Location, Daniel G. Miller Sep 2022

Finite Fatigue Life Prediction Of Additively Manufactured Aircraft Engine Turbine Blade With Respect To Internal Defect Size And Location, Daniel G. Miller

Theses and Dissertations

Current fatigue life modeling techniques with respect to defects emphasize the dependence on the defect size with respect to fatigue life, but does not account for the effects of where a defect might be located. This research outlines a process to include defect location into the model analysis for a more precise prediction of the number of cycles to failure and where the finial failure could occur within a component. The focus is on a turbine blade structure using IN718 subjected to a pure vibratory load. The basic model predicts component life using a stress map from the frequency analysis …


Orbit Determination With Event-Based Cameras To Improve Space Domain Awareness, Conor M. Wisentaner Sep 2022

Orbit Determination With Event-Based Cameras To Improve Space Domain Awareness, Conor M. Wisentaner

Theses and Dissertations

The objective of this research is to assess the utility of a COTS EBC for SDA applications by evaluating its ability to produce data for orbit updates of resident space objects. Unlike traditional frame-based imaging sensors, the pixels on an EBC activate independently when a change in brightness is detected to produce a continuous data flow on a per pixel basis. This unique functionality provides much higher temporal resolution than traditional frame-based sensors, such that an EBC can generate far more data points from a single observation than a frame-based sensor. However, current COTS EBCs have less spatial resolution than …


Mechanical Properties And Tension-Tension Fatigue Behavior Of A Novel Additively Manufactured Polymer Matrix Composite At Room And Elevated Temperature, Grayson M. Harber Sep 2022

Mechanical Properties And Tension-Tension Fatigue Behavior Of A Novel Additively Manufactured Polymer Matrix Composite At Room And Elevated Temperature, Grayson M. Harber

Theses and Dissertations

The tension-tension fatigue behavior of a novel additively manufactured AM carbon fiber reinforced polymer matrix composite was studied. This novel material system consists of T1100 carbon fibers, and a UV photocured resin developed by Continuous Composites and Sartomer. Tensile properties and tension-tension fatigue were investigated for the 090 fiber orientation as well as for the ±45 fiber orientation. Specimens with 0/90 fiber orientation were tested at ambient laboratory temperature 23 °C and at elevated temperature 150 °C, while the specimens with the ±45 fiber orientation were tested only at ambient laboratory temperature. Tension-tension fatigue testing was carried out with a …


A Deep Learning Approach For Airport Runway Identification From Satellite Imagery, Mahmut Gemici Aug 2022

A Deep Learning Approach For Airport Runway Identification From Satellite Imagery, Mahmut Gemici

Theses and Dissertations

The United States lacks a comprehensive national database of private Prior Permission Required (PPR) airports. The primary reason such a database does not exist is that there are no federal regulatory obligations for these facilities to have their information re-evaluated or updated by the Federal Aviation Administration (FAA) or the local state Department of Transportation (DOT) once the data has been entered into the system. The often outdated and incorrect information about landing sites presents a serious risk factor in aviation safety. In this thesis, we present a machine learning approach for detecting airport landing sites from Google Earth satellite …


Experiments To Mitigate Flow Recirculation In A Closed Anechoic Chamber Using Mesh Screens As Turbulence Suppressors, Tori Kay Wolverton Aug 2022

Experiments To Mitigate Flow Recirculation In A Closed Anechoic Chamber Using Mesh Screens As Turbulence Suppressors, Tori Kay Wolverton

Theses and Dissertations

The desire to gather acoustic data of a propeller in simulated hover without environmental effects is met with the challenge of recirculating flow in a closed anechoic chamber. Flow recirculation in an anechoic chamber is not ideal because the effects of it being ingested by the rotor cause unsteady loadings on the propeller. This unsteady loading causes vortex noise from the turbulence introduced by the recirculation of the flow. The aim is to study the acoustic signature of a propeller separate from external factors and engine noise. Two different propellers with three different screen combinations were tested in a closed …


Three-Axis Magnetometer Calibration With Norm Preservation, Seth Lichlyter Aug 2022

Three-Axis Magnetometer Calibration With Norm Preservation, Seth Lichlyter

Theses and Dissertations

This thesis proposes a set of methods for the purpose of improving the calibration of three-axis magnetometers. Specifically, these methods aim to improve the accuracy of the bias estimation methods currently in use. The first proposed method utilizes a constrained optimization problem based on norm preserving. The second proposed method finds the same bias estimate as the first method, but in a computationally more efficient manner. The last proposed method tackles the case where the value of the local geomagnetic field is only imprecisely known. Computer simulations demonstrate the viability of the proposed methods.


Numerical Study Of The Effects Of Injector Geometry On The Performance Of Rotating Detonation Engines, Xavier Roy Jul 2022

Numerical Study Of The Effects Of Injector Geometry On The Performance Of Rotating Detonation Engines, Xavier Roy

Theses and Dissertations

A study of the impact of injector geometry on the performance of rotating detonation engines is performed. A numerical scheme is developed to represent the rotating detonation engine physics. In order to simulate the interaction between the chamber and the injectors, a multizone capability is implemented inside the numerical tool. The model is calibrated to represent a hydrogen-air detonation. The rotating detonation engine annular chamber is unwrapped and studied as a two-dimensional planar domain with a periodic boundary condition. Several numerical experiments are conducted. In particular, injection parameters are examined, such as the injector inflow to channel area ratio, injection …


Propellant Optimization For A Pulsed Solid Propellant Thruster System For Small Satellites, Timothy Aaron Blackman Jul 2022

Propellant Optimization For A Pulsed Solid Propellant Thruster System For Small Satellites, Timothy Aaron Blackman

Theses and Dissertations

CubeSats have historically been used mostly for education, technology demonstration, remote sensing, and amateur radio relay applications. Yet with increased maneuvering capability, they can become effective tools in on-orbit servicing and space debris removal. To make this a reality, CubeSats must be enabled to perform effective rendezvous and proximity operations with non-cooperative client objects, requiring a high-thrust propulsion system. As CubeSats are inherently constrained in their volume and mass, any propulsion system must feature a high specific impulse to minimize the propellant mass requirement. As CubeSats are commonly launched as secondary payload, the use of pressurized propellant tanks is typically …


Electromagnetic Interference Shielding Effectiveness Of A Layered System Consisting Of A Carbon Nano-Reinforced Polymer Composite Coated With Metal Oxide And Graphite, Veronica Montserrat Serrato Jul 2022

Electromagnetic Interference Shielding Effectiveness Of A Layered System Consisting Of A Carbon Nano-Reinforced Polymer Composite Coated With Metal Oxide And Graphite, Veronica Montserrat Serrato

Theses and Dissertations

In this study, the electromagnetic interference (EMI) shielding effectiveness (SE) of vapor grown carbon nanofiber (VGCNF) reinforced polyvinylidene difluoride (PVDF) composite and PVDF/VGCNF thermally sprayed with magnetite (Fe3O4) and graphite has been investigated. EMI SE evaluations were performed in the frequency range of 30 kHz-1.5 GHz. The developed nanocomposite (NC) system was fabricated by high shear mixing using a Banbury type mixer. The material was then subjected to compression molding. Subsequently, the films were thermally sprayed using Fe3O4/graphite powder. The NC and coated NC films had average thicknesses of 0.82 mm and 0.93 mm, respectively. The NC films were subjected …


Augmenting Heads-Up Displays With Intelligent Agents: A Human Factors Approach, Grant Edward Morfitt Jun 2022

Augmenting Heads-Up Displays With Intelligent Agents: A Human Factors Approach, Grant Edward Morfitt

Theses and Dissertations

Situational awareness, both tactical and strategic, is essential for humans engaged in complex tasks in civilian and military theaters of operation. Previous work has shown that heads-up displays are effective tools for providing critical information to operators in such situations. Hitherto, heads-up displays have been designed to relay instrument and sensor information to the operator in a topical, timely, and accurate manner. There is a large body of complementary work in the area of human factors that deals with presenting information to a user without detracting from the primary mission. This thesis investigates, measures, and validates the effectiveness of a …


Performance Study Of Post-Processed Additively Manufactured Low Thrust Nozzles, Tyler W. Gerhold Jun 2022

Performance Study Of Post-Processed Additively Manufactured Low Thrust Nozzles, Tyler W. Gerhold

Theses and Dissertations

This research explores metal post-processing techniques to effectively reduce the large anomalous protrusions found in small additively manufactured low thrust rocket nozzles. Research has found that nozzles of this kind can experience losses in thrust of over 40%. Analytic theory of adiabatic nozzle flow with viscous losses for additively manufactured nozzles does not align with what has been found when tested experimentally. Compressible flow losses, such as shock wave formation inside the nozzle diverging cone, are likely the leading causes of such loss. Reduction in nozzle irregularities can likely yield results seen in analytic theory with similar performance to traditional …


Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao May 2022

Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao

Theses and Dissertations

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …


Structural Sizing Of Post-Buckled Thermally Stressed Stiffened Panels, Walid Arsalane May 2022

Structural Sizing Of Post-Buckled Thermally Stressed Stiffened Panels, Walid Arsalane

Theses and Dissertations

Design of thermoelastic structures can be highly counterintuitive due to design-dependent loading and impact of geometric nonlinearity on the structural response. Thermal loading generates in-plane stresses in a restrained panel, but the presence of geometric nonlinearity creates an extension-bending coupling that results in considerable transverse displacement and variation in stiffness characteristics, and these affects are enhanced in post-bucking regimes. Herein a methodology for structural sizing of thermally stressed post-buckled stiffened panels is proposed and applied for optimization of the blade and hat stiffeners using a gradient-based optimizer. The stiffened panels are subjected to uniform thermal loading and optimized for minimum …


Flight Test Of A Floatplane Modification To The C-130j Aircraft, Daniel Jacob Kulp May 2022

Flight Test Of A Floatplane Modification To The C-130j Aircraft, Daniel Jacob Kulp

Theses and Dissertations

This report details the future flight test of a potential amphibious modification to the C-130J Super Hercules. The goal of the project is to enable an amphibious capability through the installation of dual floats via a truss structure attached to the fuselage. This project uses an iterative design process which leans heavily on digital engineering and subscale testing. Through the iterative design process, several float and truss versions underwent 6-degree of freedom aerodynamic simulation and finite element analyses to validate landing load limits and stability and control parameters. These simulators informed subsequent versions which underwent subscale physical testing in a …


Residual Strength Estimation Of Degraded Bonded Joints Based On Non-Destructive Evaluations, Guilherme Garcia Momm May 2022

Residual Strength Estimation Of Degraded Bonded Joints Based On Non-Destructive Evaluations, Guilherme Garcia Momm

Theses and Dissertations

Pioneer designers acknowledged structural bonding advantages over other joining methods, sparking many aerospace applications. Nonetheless, durability issues, weak bonds, and the inability to non-destructively interrogate bond quality after-the-fact hindered widespread bonding use. These challenges also contributed to several aircraft accidents, fostering extensive related research. Firstly, we examined the bonding operational history in aviation. The challenge to simulate or experimentally reproduce bonded joints’ long-term behavior under real-life conditions magnifies the value of in-service data. Since 1944 the International Civil Aviation Organization has recommended investigating aircraft incidents/accidents. Among numerous investigation reports publicly available, we identified 73 bond-related occurrences involving type-certified aircraft registered …


Computer Vision Of Analog Gauges As An Alternative To Digital Flight Test Instrumentation, Michael William James May 2022

Computer Vision Of Analog Gauges As An Alternative To Digital Flight Test Instrumentation, Michael William James

Theses and Dissertations

Currently, there are a couple of options to gather stick force data from flight test aircraft. Either the aircraft is instrumented with costly piezoelectric force sensors and recorders integrated into the aircraft stick, or the test pilot must use a traditional analog stick force gauge with a pointer and telltale. The conventional stick force gauge works well when the pilot has the mental and physical bandwidth to read and remember, or record, the stick force values throughout the maneuver but does not suffice when in a task saturated, high g force maneuver such as the windup turn. This project proposes …


Flight Test Evaluation Of Piper Seminole, Brian-Emmanuel Hopeton Walters May 2022

Flight Test Evaluation Of Piper Seminole, Brian-Emmanuel Hopeton Walters

Theses and Dissertations

After taking FTE 5702 – Stability and Control class, taught by Dr.Kimberlin, I understood the concept of using an aircraft and then testing how it handles in the air. Almost all flight tests done on aircraft are done by the manufacturer. Some aircraft may have a lot of comprehensive information available, while others have little to no information. It can also be hard to find the specific data that a pilot or owner desires. These various tests allow a greater understanding of aircraft stability and performance available for analysis and relating. The aircraft I flew during FTE 5702 class was …


Carbon Fiber Interleaved Polyester Laminate Strength Testing With Correlation In Finite Element Simulations, Hieu Le Huynh May 2022

Carbon Fiber Interleaved Polyester Laminate Strength Testing With Correlation In Finite Element Simulations, Hieu Le Huynh

Theses and Dissertations

Delamination of composite structures under impact conditions has been a catastrophic and economic issue in the past and is still a problem today. Many techniques have been used to improve the toughness in composite laminates. An example of a previous dissertation was performed by Adnan Gheryani titled: “Analysis of Polyester Interleafs for Toughness Enhancement in Composite Structures.” Gheryani’s study shows that adding in polyester interleafs into composite laminates made primarily from carbon fiber fabric adds ductility and resists crack growth after delamination, which leads to improvement of the overall toughness of the laminate. However, improvements in toughness, strength, and stiffness …


Manufacturing Process Considerations When Transitioning From Thermoset To Thermoplastic Composite Material For Urban Air Mobility Propellers, Samuel Leonard Jones Iii Apr 2022

Manufacturing Process Considerations When Transitioning From Thermoset To Thermoplastic Composite Material For Urban Air Mobility Propellers, Samuel Leonard Jones Iii

Theses and Dissertations

Aerospace manufacturing has seen continually increased use of carbon fiber reinforced polymers in aircraft structures. The favorable strength to weight ratios, as well as the increased resistance to fatigue and corrosion, compared to metallic structures, provide a common argument for further research and development of composite airframes. Two main classes of carbon fiber reinforced polymers can be distinguished, thermosetting polymers and thermoplastic polymers. Thermoset polymers have been relied on for decades for the ability to reliably produce strong laminates for aircraft structures. By comparison thermoplastic polymers experience less comparable utilization on primary structures despite boasting similar or greater performance capabilities …


Standards-Compatible Smoke Points For Mono- And Un- Substituted Cycloalkane Fuel Components, Adekunle Vincent Adeniyi Mar 2022

Standards-Compatible Smoke Points For Mono- And Un- Substituted Cycloalkane Fuel Components, Adekunle Vincent Adeniyi

Theses and Dissertations

Emissions from the aviation industry have increased significantly over the decades and may continue to pose an environmental threat. Accordingly, efforts are being made to replace conventional aviation fuels with more sustainable alternatives that can both reduce net CO2 emissions as well as reduce other pollutants (i.e., particulates). Conventional jet fuels include aromatic species, which have high sooting tendency. Therefore, to reduce particulate emissions, the fuel aromatics content must be reduced. Cycloalkanes have potential for replacing aromatics content in jet fuel but, compared to other broad classes of chemical species that make up conventional and alternative jet fuel, there is …


Uav Positioning Data Determined Via Aruco Tags For Aircraft Surface Inspection, Caleb B. Schmidt Mar 2022

Uav Positioning Data Determined Via Aruco Tags For Aircraft Surface Inspection, Caleb B. Schmidt

Theses and Dissertations

Aircraft are frequently inspected to ensure that military and civilian safety standards are adhered to. These inspections are performed pre- and post-flight and are currently performed by trained maintenance personnel. This work furthers the automation of aircraft surface inspection by using ArUco tags to determine the position of the UAV during aerial inspections. The ArUco tag based position data was then compared to a highly accurate infrared motion capture system to determine the viability of this for accurate positioning of the vehicle. This work includes flight experiments with two different UAVs to perform a system viability comparison.


Covariance Analysis For Multi-Source Navigation Architecture, Tristan T. Williams Mar 2022

Covariance Analysis For Multi-Source Navigation Architecture, Tristan T. Williams

Theses and Dissertations

Currently, analysis on navigation systems can be slow and computationally expensive using Monte Carlo approaches. Covariance analysis is a tool that can return trade space analysis results promptly and can be computationally reasonable. This research aims to create a covariance analysis tool in a new navigation framework architecture, PntOS. The creation of this covariance tool is explained in coordination with the tool being used in a few different navigation scenarios with the results. These scenarios include a Doppler LiDAR velocity sensor and magnetic anomaly navigation.