Engineering Commons^™

The Effects Of Elevator Rate Limiting And Stick Dynamics On Longitudinal Pilot-Induced Oscillations, Patrick J. Peters

Theses and Dissertations

This report presents the results of an investigation into the effects of elevator rate limiting and stick dynamics on longitudinal pilot-induced oscillations (PIO). A simulation study was conducted to prepare for the flight test, but also to gain insight into the effects of rate limiting and stick dynamics. Due to the non-numerical nature of the simulation results, a flexible three-phase flight test plan was developed, first varying the rate limits, then varying the stick dynamics, and finally flying a matrix determined in the first two phases. There were three major conclusions. First, the offset landing task flown was insufficient to …

Cosmic Calling

Syracuse University Magazine

No abstract provided.

The Airline Quality Rating 1997, Brent Bowen, Dean Headley, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 97-9

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline performance on combined multiple factors important to consumers. Development history and calculation details for the AQR rating system are detailed in The Airline Quality Rating 1991 issued in April, 1991, by the National Institute for Aviation Research at Wichita State University. This current report, Airline Quality Rating 1997, contains monthly Airline Quality Rating scores for 1996. Additional copies are available by contacting Wichita State University or University of Nebraska at Omaha. The Airline Quality Rating 1997 is …

An Investigation Of The Hydrodynamic Effects Of Enteromorpha Clathrata Fouling On Hydrofoils, Brian J. Collino

Master's Theses - Daytona Beach

The purpose of this investigation was to determine the effects of biological fouling on hydrofoils. NACA 4412 and 4415 hydrofoil models with 6 inch chord and 8 inch span were used in this study. A water tunnel facility was designed and constructed to perform the tests, and the results were verified using computational fluid dynamic modeling. The CFD software package Fluent was used to create a two dimensional model of the water tunnel test section and hydrofoil. The model was meshed using a Laplacian grid smoothing technique that forced the structured grid lines to follow the same approximate contour as …

Adaptive Critic Based Neurocontroller For Autolanding Of Aircrafts, S. N. Balakrishnan, Gaurav Saini

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, adaptive critic based neural networks have been used to design a controller for a benchmark problem in aircraft autolanding. The adaptive critic control methodology comprises successive adaptations of two neural networks, namely action and critic network (which approximate the Hamiltonian equations associated with optimal control theory) until closed loop optimal control is achieved. The autolanding problem deals with longitudinal dynamics of an aircraft which is to be landed in a specified touchdown region (within acceptable ranges of speed, pitch angle and sink rate) in the presence of wind disturbances and gusts using elevator deflection as the control …

Eigenvalue And Eigenvector Determination For Damped Gyroscopic Systems, D. P. Malone, Don L. Cronin, Timothy W. Randolph

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Adaptive Critic Based Neurocontroller For Autolanding Of Aircraft With Varying Glideslopes, Gaurav Saini, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, adaptive critic based neural networks have been used to design a controller for a benchmark problem in aircraft autolanding. The adaptive critic control methodology comprises successive adaptations of two neural networks, namely `action' and `critic' networks until closed loop optimal control is achieved. The autolanding problem deals with longitudinal dynamics of an aircraft which is to be landed in a specified touchdown region in the presence of wind disturbances and gusts using elevator deflection as the control for glideslope and flare modes. The performance of the neurocontroller is compared to that of a conventional PID controller. Neurocontroller's …

Odie: Orbiting Dragfree International Experiment, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "ODIE: Orbiting Dragfree International Experiment" from 1997.

A Feasibility Study Of Fuel Cell Cogeneration In Industry, Scott B. Phelps, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

Up until now, most of the literature on fuel cell cogeneration describes cogeneration at commercial sites. In this study, a PC25C phosphoric acid fuel cell cogeneration system was designed for an industrial facility and an economic analysis was performed. The US DOE Industrial Assessment Center (IAC) database was examined to determine what industry considers a good investment for energy saving measures. Finally, the results of the cogeneration analysis and database investigation were used to project the conditions in which the PC25C might be accepted by industry.

Analysis of IAC database revealed that energy conservation recommendations with simple paybacks as high …

A Finite Element Formulation For Aft Fan Duct Acoustic Radiation, Walter Eversman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A finite element code has been developed for the prediction of the radiated acoustic field in and around the aft fan duct of a turbofan engine. The acoustic field is modeled based on the assumption that the steady flow in and around the nacelle is irrotational as is the acoustic perturbation. The geometry of the nacelle is axisymmetric, and the acoustic source is harmonic and decomposed into its angular harmonics. The steady flow is computed on the acoustic mesh and provides data for the acoustic calculations. The jet is included in the steady flow potential flow model by separating the …

Radiative Heating In Scramjet Combustors, Harlan F. Nelson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Currently, there is considerable interest in scramjet engines for hypersonic aircraft and missiles. This paper presents preliminary calculations of the radiative heating of the walls of scramjet combustion chambers. The analysis assumes isothermal, constant property flow fields that are representative of actual combustor flow fields. The fuel is H2, and N2 is taken as inert. Temperature in the combustor is on the order of 2000-3000 K and the pressure is of the order of 5 atm. The combustion products consist mainly of H2O and OH. These gases are strong radiators in the infrared. Radiation heating can be significant because of …

A System For Collecting Milligram Quantities Of Cloud Condensation Nuclei, Darryl J. Alofs, Donald E. Hagen, Steven D. Medley, Daniel R. White, John L. Schmitt, Allen L. Williams

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An Experimental System to Collect Cloud Condensation Nuclei (CCN) Onto Filters in Amounts Sufficient for Chemical Analysis is Described. This Experimental Apparatus is Designed to Process Ambient Air at a Rate of More Than 1 M3/min. Two Identical Systems Have Been Built. One is Installed in a Laboratory at Rolla, MO. the Other is Installed on an 11 M Long Trailer. the System Isolates Three Size Classes of CCN, Having Mass Median Diameters of 0.27, 0.12, and 0.075 Μm, Respectively, and Mass Collection Rates of 11.5, 1.28, and 0.13 Mg/day, Respectively. the above Sizes and Collection Rates Are Obtained from …

Vehicle Performance Optimization Utilizing The Air Turbo-Ramjet Propulsion System; Methodology Development And Applications, Kirk Christensen

Doctoral Dissertations

"The ATR (Air TurboRocket) is an air breathing propulsion system in which the turbocompressor turbine is powered by a hot drive gas which is generated independently of the air flow through the compressor. The ATR has a lower specific impulse (Isp) and higher thrust compared to a similar size turbojet but a lower thrust and higher Isp compared to similar size solid rocket motor (SRM). This work defines the benefits of ATR propulsion for tactical vehicles.

ATR simulation codes were developed to support analysis of hypothetical ATR powered vehicles. Both turbojet powered and SRM powered vehicles were also evaluated against …

Iswe: A Case Study Of Technology Transfer, Michael P.J. Benfield

Honors Capstone Projects and Theses

No abstract provided.

Burst Pressure Prediction Of Filament Wound Composite Pressure Vessels Using Acoustic Emission, Marcus Elwood Fisher

Master's Theses - Daytona Beach

This research demonstrates how acoustic emission (AE) data from flaw growth activity can be used to predict burst pressures in filament wound composite pressure vessels. Acoustic emission data were taken during hydroproof testing for a set of eleven ASTM standard 5.75 inch diameter fiberglass/epoxy bottles. Amplitude distributions were created using only the AE data up to 25% of the expected burst pressure to simulate low level proof loadings (thereby avoiding damage to the bottles). The bottles were tested at three different temperatures -- 32°F, 70°F, and 110°F - and hydroproofed using two different pressurization schemes and two transducer configurations. Moreover, …

Multiple Model Adaptive Estimation And Control Redistribution For The Vista F-16, Robert W. Lewis Sr.

Theses and Dissertations

Performance characteristics of a Multiple Model Adaptive Estimation and Control Redistribution (MMAE/CR) algorithm are evaluated against single and double actuator and sensor failures. MMAE alone can compensate for sensor failures, whereas Control Redistribution compensates for actuator failures by redistributing commands, initially intended for failed actuators, to the unfailed actuators in such a way that the desired system response is achieved. Both failure detection and compensation capabilities are developed and analyzed through an extensive amount of simulation data, particularly addressing multiple failures. Simulations are performed utilizing the high fidelity, non-linear six degree of freedom Simulation Rapid Prototyping Facility for the VISTA …

Model Predictive Control Of Aerospace Systems, Derek W. Ebdon

Theses and Dissertations

The primary objective of this thesis is to explore the fault tolerance capabilities of a state space formulation of MPC. Subsequent to a simulated control surface failure on the F-18 High Alpha Research Vehicle (HARV), the MPC controller will attempt to maintain stability and nominal performance while tracking a setpoint. Secondary objectives include studying the effect of data sample rate and MPC horizon lengths on system performance. These objectives will be accomplished using Matlab to develop the MPC controller and Simulink to demonstrate its effectiveness through simulation.

Performance Analysis Of A Liquid Metal Heat Pipe Space Shuttle Experiment, Timothy J. Dickinson

Theses and Dissertations

Future spacecraft technologies require advanced high-temperature thermal control systems. Liquid metal heat pipes are considered ideally suited for such applications. However, their behavior during microgravity operation is not yet understood. This study investigated liquid metal heat pipe performance in such an environment. Three stainless steel/potassium heat pipes were flown on space shuttle mission STS-77 in May 1996. The objectives of the experiment were characterization of the frozen startup and restart transients, comparison of flight and ground test data to establish a performance baseline for analytical model validation, and assessment of three different heat pipe designs. Heat pipe performance was characterized …

Multidisciplinary And Multiobjective Optimization In Conceptual Design For Mixed-Stream Turbofan Engines, Luc J. J. P. Nadon

Theses and Dissertations

Despite major advances in design tools such as engine cycle analysis software and computer aided design, conceptual gas turbine engine design is essentially a trial-and-error process based on the experience of engineers. Modern optimization concepts, such as multidisciplinary optimization (MDO), and multiobjective optimization (MOO), linked with sequential quadratic programming (SQP) methods and genetic algorithms (GA), were applied to the conceptual engine design process to automate the conceptual design phase. Robust integrated computer codes were created to find the optimal values of eight engine parameters in order to minimize fuel usage, aircraft cost and engine annulus area over a given mission. …

Residual Strength And Fatigue Characterization Of Scs-6/Ti-6-4, Sang-Myung Lee

Theses and Dissertations

Metal matrix composite have potential in a variety of aerospace applications, but they should be better understood before they can be employed. Despite the many studies that have contributed to characterizing the fatigue response of titanium alloy MMCs, few have researched the residual strength. The purpose of this study was to investigate the residual strength and the frequency effects on the residual strength of an unidirectional laminate of SCS-6/Ti-6-4, a titanium alloy matrix based composite under tension-tension, load-controlled conditions at elevated temperatures and different frequencies. Specimens were fatigued at frequencies of 1 and 0.01Hz, and at maximum stress of 900MPa …

Influence Of Tip Clearance On The Flowfield In A Compressor Cascade With A Moving Endwall, Richard J. Mcmullan

Theses and Dissertations

The effects of changing the blade tip clearances on the velocity and pressure flowfields within a compressor cascade were investigated in this experimental thesis. All moving endwall measurements were taken at a constant flow coefficient of 0.5 and tip clearances of 0.5, 1.0 and 2.0 percent chord. Hot-wire/film probes were used to determine the three-dimensional velocity vector components in various transverse planes - one upstream of the leading edges of the blades, three within the blade cascade and one downstream of the trailing edges of the blades. The transverse velocity vector plots showed a scraping of the tip leakage vortex …

Optimization Of A Gps-Based Navigation Reference System, Jason B. Mckay

Theses and Dissertations

The development of increasingly accurate new aircraft navigation systems has caused the Air Force to develop a new Navigation Reference System to test them, called the Submeter Accuracy Reference System (SARS). The SARS is an inverted GPS system which consists of an array of GPS receivers on the ground and an airborne pseudolite mounted on the test aircraft. The SARS will provide a proof position estimate that is used to check the navigation system under test. Unfortunately, ground based inverted GPS systems tend to suffer from high geometric sensitivity to measurement errors. This research tackles the problem of optimizing the …

Experimental Investigation Of Compressible Boundary Layers Under The Influence Of Pressure Gradients, Raymond C. Wier

Theses and Dissertations

This study examined the effect of mild pressure gradients on the mean and turbulent flow of high-speed boundary layers. Three Mach numbers (1.7, 3.0 and 5.0) were investigated. Three pressure gradients were examined; a zero pressure gradient (ZPG), a favorable pressure gradient (FPG), and a combined pressure gradient (CPG). The CPG consisted of an adverse pressure gradient followed by a favorable pressure gradient. Conventional pressure probes, hot-wire and particle image velocimetry (PIV) were used to examine the flow. Measurement included mean velocity, velocity turbulence intensity, mass flux turbulence intensity and energy spectra. Instantaneous (10 nsec) Mie scattering flow visualizations were …

Experimental Investigation Of Transverse Supersonic Gaseous Injection Enhancement Into Supersonic Flow, Mark P. Wilson

Theses and Dissertations

In pursuit of more efficient and effective fuel-air mixing for a SCRAMJET combustor, this study was conducted to investigate relative near field enhancements of penetration and mixing of a discrete low-angled (25°) injected air jet into a supersonic (M=2.9) cross flow. The enhancements were achieved by injecting the transverse air jet parallel to the compression face of eight different ramp geometries. The jet-ramp interactions created collinear shock structures, baroclinic torque vorticity enhancement, ramp spillage enhanced vorticity, magnus effect penetration enhancement, and increased total pressure loss. Shadowgraph photography was used to identify the shock structures and interactions in the flow field. …

The Preliminary Design Of A Standardized Spacecraft Bus For Small Tactical Satellites, Gerald Ashby, Darren Buck, Robert Carneal Iv, Tansel Cokuysal, Ahmet Donmez, James From, Todd Krueger, Brian Robinson

Theses and Dissertations

Current satellite design philosophies concentrate on optimizing and tailoring a particular satellite bus to a specific payload or mission. Today's satellites take a long time to build, checkout, and launch. An alternate approach shifts the design paradigm to one that focuses on access to space, enabling tactical deployment on demand and the capability to put current payload technology into orbit, versus several years by today's standards, by which time the technology is already obsolete. This design study applied systems engineering methods to create a satellite bus architecture that can accommodate a range of remote sensing mission modules. System-level and subsystem-level …

Detection Of Fatigue Crack Growth In A Simulated Aircraft Fuselage, Michael Lee Marsden

Master's Theses - Daytona Beach

Acoustic emission (AE) nondestructive testing can detect fatigue cracks as they occur in complex structures. One use for AE has been in-flight detection of fatigue cracks in aircraft. The KC-135 aircraft were successfully monitored as early as 1979. The main problem with this and subsequent applications was an unfavorable signal to noise ratio, the key being to separate the small amplitude crack signals from the large amplitude ambient noise. This was accomplished here through the use of a Kohonen self-organizing map (SOM) neural network.

In order to simulate a fuselage undergoing fatigue, a pressure vessel was constructed from a 0.040 …

A Methodology For The Prediction Of The Empennage In-Flight Loads Of A General Aviation Aircraft Using Backpropagation Neural Networks, Maciej Marciniak

Master's Theses - Daytona Beach

Backpropagation neural networks have been used to predict strain resulting from the maneuver in-flight loads in the empennage structure of a Cessna 172P. The purpose of this research was to develop a methodology for the prediction of strain in the tail section of a general aviation aircraft and to determine the minimum set of sensors necessary to adequately train the neural networks. Linear accelerometer, angular accelerometer, rate gyro, and strain gage signals were collected in flight using DAQBook portable data acquisition system for dutch-roll, roll, sideslip left, sideslip right, stabilized g turn left, stabilized g turn right, and push-pull maneuvers …

Parametric Correlations For Generic Scramjet Combustors With Ramp-Type Injectors, Jason Granville Bush

Mechanical & Aerospace Engineering Theses & Dissertations

Development of an efficient scramjet combustor requires the use of computational models due to the cost of full-scale physical testing in the speed regime of Mach 10 through Mach 18. This study focuses upon the database generated by one such computational model, SHIP3D, which describes a generic scramjet combustor using ramp-type file! injectors. Three generalized parametric equations have been developed from this database, which describe the fuel-air mixing efficiency within the scramjet combustor as a function of normalized-axial combustor distance, ramp injector-region lift coefficient, and stoichiometry. It is shown that one of the three equations nearly models the trends as …

Dynamics And Control Of A Three Dimensional Gantry Crane With Cable Flexibility, Uchendu H. Eke

Mechanical & Aerospace Engineering Theses & Dissertations

The control of payload swing in industrial gantry cranes is a topic of widespread interest. In this thesis, the control of the swing of a payload idealized by a point mass assumption is investigated utilizing s, compact robotics matrix/vector representation of the dynamical model. In this form, this particular system can be viewed as sn underactuated manipulator with equal numbers of active and passive degrees of freedom. The full three dimensional model is developed and linearized by modelling the cable as a single thread of fiexible wire and the degree of dynamic coupling between the active and passive coordinates is …

The Effectiveness Of Film Cooling In A Hypersonic Flowfield With Favorable Pressure Gradients, Julie A. Young

Mechanical & Aerospace Engineering Theses & Dissertations

The impetus of this technical document is to report results of aerothermodynamic cooling of a scramjet nozzle under favorable pressure gradients. The goals of film cooling are to protect the nozzle skin from the high enthalpy combustor flow, reduce regenerative cooling requirements, and decrease nozzle skin friction. A hypersonic nozzle configuration for which experimental data exists was selected as the basis of this numerical study. As a first step, the numerical results of film cooling along a flat plate are compared to previous literature to validate the numerical model. Subsequently, computations are performed to study the effects of varying the …