Unmanned Aerial Logistics Vehicles
Presently, United States Army battlefield supply distribution does not involve unmanned aerial logistic vehicles. The United State military's Joint Vision 2020 and its tenet of Focused Logistics provide vision for force development allowing for the exploration of the unmanned aerial logistics vehicles concept. This thesis explores the primary research question: Could the United States Army benefit by pursuing an unmanned aerial logistic vehicle concept? Secondary questions are defined and addressed: (1) Can unmanned aircraft realize a logistic supply delivery process? (2) Which of the possible unmanned aircraft processes is the recommended process? and (3) Which existing logistic processes are to be improved? All questions are explored by applying the Wisconsin 7-Step Problem-Solving Strategy: stating the problem, determining solution criteria, gathering needed information, generating potential solutions, comparing solutions and the problem, selecting the solution, and preparing communications. Multiple unmanned aerial logistics concept options provide potential solutions involving unmanned fixed-wing aircraft, rotary-wing aircraft, blimps, and precision airdrop systems, alone or in combination, and each yielding potential benefits when compared to existing supply distribution processes. Were an unmanned aerial logistic vehicle system actualized, some part of the United States Army's existing supply distribution process could be improved.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Biological Concepts for Design and Operation of the Activated Sludge Process
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Systems-Level Feasibility Analysis of a Microsatellite Rendezvous With Non-Cooperative
The United States is very dependant upon the use of space. Any threat to our ability to use it as desired deserves significant study. One such asymmetric threat is through the use of a microsatellite. The feasibility of using a microsatellite to accomplish an orbital rendezvous with a non-cooperative target is being evaluated. This study focused on identifying and further exploring the technical challenges involved in achieving a non-cooperative rendezvous. A systems engineering analysis and review of past research quickly led to a concentration on the guidance, navigation, and control (GNC) elements of the microsatellite operation. While both the control laws and orbit determination have been previously evaluated as feasible, the integration of the two remained in question. This research first validated past efforts prior to exploring the integration. Impulsive and continuous thrust control methods, and linear and nonlinear estimator filters were all candidate components to a potential system solution. A simple yet robust solution could not be found to meet reasonable rendezvous criteria, using essentially off-the-shelf technology and algorithms. Results reveal a simple linear filter is a misapplication and will not at all work. A nonlinear filter coupled with either a continuous or impulsive thrust controller was found to get somewhat close, but never close enough to attach to the target satellite. Successful GNC subsystem integration could only be achieved for a very simple case ignoring orbit perturbations such as the earth's oblateness. A top-level system architecture for a non-cooperative rendezvous microsatellite has been developed. The technical complexity, however, requires more complex algorithms to solve the rendezvous problem.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modern Airships
Modern airships by design are capable of short-take off and landings (STOL), and vertical take-off and landings (VTOL). This VTOL capability enables the airship to land practically anywhere, independent of most infrastructure support. This ability would allow deploying heavy forces to be picked up at their home-station and transported directly to a location directed by the Combatant Commander, bypassing the labor intensive and time consuming portions of the deployment process. The challenge facing DoD is determining if this type of transport is feasible and acceptable for military use. DoD has already sponsored two studies on two very different airship designs, thus demonstrating DoD is interested in the airship heavy transport concept. This monograph highlights some of the findings from those studies and looks at historically proven uses of airships and some contemporary uses as well. Contemporary transports, the deployment process, and the associated challenges for deployments are also discussed. Together this information is used to assess feasibility and acceptability of airships as heavy transports. This monograph concludes with a positive assessment for the airship and recommendations for how DoD should proceed toward the use of airships in the not too distant future.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
The Aerodynamic Performance of the Houck Configuration Flow Guides
In an effort to explore efficient wing designs for UAV's, the Air Force is investigating the patented Houck Aircraft Configuration, which is a joined-wing aircraft with curved flow guides of varying camber connecting the upper and lower wingtips. Models were drawn in three-dimensions using Solidworks with upper and lower wings drawn as identical NACA 2412 airfoil sections for all models. A variety of airfoil sections between the upper and lower wingtips were drawn and rotated to achieve a combination of cant and angle of attack variation. Subsequently, a solid part was lofted through these sections and merged with the upper and lower wings. Each model was built by a rapid prototype machine. A six-component balance in the AFIT low-speed wind tunnel provided measurements yielding the aerodynamic data of each model. Comparisons are made to the same basic planform area without flow guides and to a case where the wingtips are joined with a flat plate. At a Reynolds number of 38K, the increase in skin friction drag outweighed any possible reduction of induced drag. However for Reynolds numbers in the 57K to 120K range, improvements in L/Dmax of about 2-5% over the no flow guide case were measured.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Pilot Mental Workload Calibration
The issue of predicting high pilot mental workload is important to the United States Air Force because lives and aircraft can be lost when errors are made during periods of mental overload and task saturation. Current research efforts use psychophysiological measures such as electroencephalography (EEG), cardiac, ocular, and respiration measures in an attempt to identify and predict mental workload levels. Existing classification methods successfully classify pilot mental workload using flight data from the same pilot on the same day but unsuccessfully classify workload using data from a different pilot on a different day. The primary focus of this effort is the development of a calibration scheme that allows a small subset of salient psychophysiological features developed using actual flight data for one pilot on a given day to accurately classify pilot mental workload for a separate pilot on a different day. Extensive raw data preprocessing, including 29 Fourier transformations for each second of flight data, prepares the feature data for analysis. The signal-to-noise ratio feature screening method is employed to determine the usefulness of 151 psychophysiological features in feed-forward artificial neural networks.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
The Practical Calculation of the Aerodynamic Characteristics of Slender Finned Vehicles
The basic objective of this thesis is to provide a practical method of computing the aerodynamic characteristics of slender finned vehicles such as sounding rockets, high speed bombs, and guided missiles. The aerodynamic characteristics considered are the normal force coefficient derivative, c(sub N(sub alpha)); center of pressure, bar-X; roll forcing moment coefficient derivative, c(sub l(sub delta)); roll damping moment coefficient derivative, c(sub l(sub p)); pitch damping moment coefficient derivative, c(sub mq); and the drag coefficient, c (sub D). Equations are determined for both subsonic and supersonic flow. No attempts is made to analyze the transonic region. The general configuration to which the relations are applicable is a slender axisymmetric body having three or four fins.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Comparison of High Aspect Ratio Cooling Channel Designs for a Rocket Combustion Chamber With Development of an Optimized Design
An analytical investigation on the effect of high aspect ratio (height/width) cooling channels, considering different coolant channel designs, on hot-gas-side wall temperature and coolant pressure drop for a liquid hydrogen cooled rocket combustion chamber, was performed. Coolant channel design elements considered were: length of combustion chamber in which high aspect ratio cooling was applied, number of coolant channels, and coolant channel shape. Seven coolant channel designs were investigated using a coupling of the Rocket Thermal Evaluation code and the Two-Dimensional Kinetics code. Initially, each coolant channel design was developed, without consideration for fabrication, to reduce the hot-gas-side wall temperature from a given conventional cooling channel baseline. These designs produced hot-gas-side wall temperature reductions up to 22 percent, with coolant pressure drop increases as low as 7.5 percent from the baseline. Fabrication constraints for milled channels were applied to the seven designs. These produced hot-gas-side wall temperature reductions of up to 20 percent, with coolant pressure drop increases as low as 2 percent. Using high aspect ratio cooling channels for the entire length of the combustion chamber had no additional benefit on hot-gas-side wall temperature over using high aspect ratio cooling channels only in the throat region, but increased coolant pressure drop 33 percent. Independent of coolant channel shape, high aspect ratio cooling was able to reduce the hot-gas-side wall temperature by at least 8 percent, with as low as a 2 percent increase in coolant pressure drop. ne design with the highest overall benefit to hot-gas-side wall temperature and minimal coolant pressure drop increase was the design which used bifurcated cooling channels and high aspect ratio cooling in the throat region. An optimized bifurcated high aspect ratio cooling channel design was developed which reduced the hot-gas-side wall temperature by 18 percent andThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Input Shaping to Reduce Solar Array Structural Vibrations
Structural vibrations induced by actuators can be minimized using input shaping. Input shaping is a feedforward method in which actuator commands are convolved with shaping functions to yield a shaped set of commands. These commands are designed to perform the maneuver while minimizing the residual structural vibration. In this report, input shaping is extended to stepper motor actuators. As a demonstration, an input-shaping technique based on pole-zero cancellation was used to modify the Solar Array Drive Assembly (SADA) actuator commands for the Lewis satellite. A series of impulses were calculated as the ideal SADA output for vibration control. These impulses were then discretized for use by the SADA stepper motor actuator and simulated actuator outputs were used to calculate the structural response. The effectiveness of input shaping is limited by the accuracy of the knowledge of the modal frequencies. Assuming perfect knowledge resulted in significant vibration reduction. Errors of 10% in the modal frequencies caused notably higher levels of vibration. Controller robustness was improved by incorporating additional zeros in the shaping function. The additional zeros did not require increased performance from the actuator. Despite the identification errors, the resulting feedforward controller reduced residual vibrations to the level of the exactly modeled input shaper and well below the baseline cases. These results could be easily applied to many other vibration-sensitive applications involving stepper motor actuators.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
An Analytical Study of T-38 Drag Reduction in Tight Formation Flight
This thesis explores the benefits of flying in a tight formation, mimicking the natural behavior of migratory birds such as geese. The first phase of the research was to determine an optimal position for the wingman of a tight formation flight of T-38 Talon aircraft using the HASC95 vortex lattice code. A second wingman was then added to determine the benefit derived by increasing formation size. The second wingman was predicted to derive an even greater induced drag benefit than the first wingman for T-38s operating at Mach 0.54 at a 10,000-foot altitude. The predicted values were 17.5% savings for the second wingman versus 15% for the first wingman. The flight test phase flew two and three-ship formations to validate the computational work. The results of the two-ship flight tests showed with 80% confidence that the wingman saved fuel in the predicted optimal position (86% wingspan lateral spacing). This position yielded actual fuel savings of 8.8% 5.0% versus the predicted 15%. The other lateral positions did not show a statistically significant fuel savings. The flight test team felt that the three-ship formation data was inconclusive due to the difficulty of trying to fly a stable position as the third aircraft in the formation without station-keeping ability.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Composite Aircraft Life Cycle Cost Estimating Model
Composite materials are beginning to comprise a greater percentage of structural materials used throughout aircraft production. The increased usage of composites has led individuals within the Air Force community to revisit aircraft life cycle cost, LCC, models. A series of affordability initiatives has culminated in significant evidence over the last decade to better quantify the impact of primarily composite structures in aircraft. The Advanced Composite Cargo Aircraft, ACCA, a research effort sponsored by the Air Force Research Lab, attempted to determine the impact of part size and large scale composite components on LCC for cargo aircraft. This research evaluates the data provided by the ACCA program and data from aerospace industry partners to modify the existing LCC models. This research finds that a relationship exists between relative part count and touch labor hours for certain cost categories, notably, design, design support, and testing. In particular, a percentage reduction in part count drives a corresponding percentage reduction in these select cost categories. These findings suggest that reduction in part count filter through most of the major cost categories during development and production. The research findings suggest that the current LCC models require modifications in the current cost estimating relationships to capture these impacts.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Experimental Studies of Liquefaction and Densification of Liquid Oxygen
The propellant combination that offers optimum performance is very reactive with a low average molecular weight of the resulting combustion products. Propellant combinations such as oxygen and hydrogen meet the above criteria, however, the propellants in gaseous form require large propellant tanks due to the low density of gas. Thus, rocketry employs cryogenic refrigeration to provide a more dense propellant stored as a liquid. In addition to propellant liquefaction, cryogenic refrigeration can also conserve propellant and provide propellant subcooling and propellant densification. Previous studies analyzed vapor conditioning of a cryogenic propellant, with the vapor conditioning by either a heat exchanger position in the vapor or by using the vapor in a refrigeration cycle as the working fluid. This study analyzes the effects of refrigeration heat exchanger located in the liquid of the common propellant oxidizer, liquid oxygen. This study predicted and determined the mass condensation rate and heat transfer coefficient for liquid oxygen.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Accident Prevention and Response Manual for Anhydrous Ammonia Refrigeration System Operators
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Static Aeroelastic Analysis of a Flexible Wing Mini Unmanned Aerial Vehicle
The static aeroelastic behavior of the Nighthawk mini unmanned aerial vehicle is examined using acombined experimental and computational approach. Three wings are examined. In order of increasingstiffness they are: a flexible wing, a stiff wing, and a fictitious rigid wing with zero deflection. Photogrammetryis used during wind tunnel testing to measure the average deflected shape of the flexible and stiff wingsduring flight. The independent variables during wind tunnel tests are angle of attack (ranging from -5.1othrough 13.4o) and velocity, which is 20 mph, 30 mph, and 40 mph. Roll angle and yaw angle are controlvariables, held constant at 0o. The measured deflection of each wing is used to adjust the wing shape forcomputational fluid dynamics analysis. Solutions are obtained for the flexible, stiff, and undeflected (or rigid)wings using a steady-state viscous flow solver with a Spalart-Allmaras turbulence model. The flexible andstiff wings experience two forms of deformation during flight. They bend upward along the span increasingthe dihedral, and the leading edge twists downward (wing washout). The amplitude of deflection is greatestfor the flexible wing. As a result, the flexible wing is more stable, but also exhibits worse static aerodynamicperformance. The rigid wing has the greatest lift (CL max=1.29) and the highest lift-to-drag ratio (L/Dmax =10.2).Stall occurs first near the root for all three wings. None of the wings stall at the tip in the range of angles ofattack tested. A separation bubble forms under the wing at angles of attack less than 8o. This separationdecreases the overall lift. It is most prominent on the flexible wing.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Development of a Screening Tool to Facilitate Technology Transfer of an Innovative Technology to Treat Perchlorate-Contaminated Water
Perchlorate contamination of drinking water is a significant problem nationwide. The purpose of this study was to develop a tool to predict the cost and performance of tailored granular activated carbon (T-GAC), an innovative technology that is being evaluated as a cost-effective treatment for perchlorate-contaminated water. The ability to accurately predict performance and cost can facilitate the transfer and commercialization of innovative technologies. In the study, a model was developed to predict T-GAC performance and life-cycle costs for removing perchlorate under varying influent water quality and technology operating conditions. The model's design parameters were obtained from laboratory rapid small-scale column tests (RSSCTs) using inverse modeling. Cost data used in the model were based on conventional GAC installations, modified to account for tailoring. The parameterized model was used to predict the observed performance from a pilot-scale field demonstration at a water treatment plant in Southern California. The model over-predicted field performance; however, it predicted reasonably well the results of laboratory RSSCTs for two waters that were not used to calibrate the model. Using the screening model, it was found that annual operation and maintenance (O and M) costs are more significant than capital costs, and that costs associated with media regeneration or replacement dominate the O and M costs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Fuel Composition Analysis of Endothermically Heated JP-8 Fuel for use in a Pulse Detonation Engine
Waste heat from a pulse detonation engine (PDE) was extracted via zeolite catalyst coated concentric tube-counter flow heat exchangers to produce supercritical pyrolytic conditions for JP-8 fuel. A sampling system and method were developed that enabled samples of reacted fuel to be extracted during steady state operation. Samples were taken over a range of heat exchanger exit temperatures from 820 K (1016 oF) to 940 K (1232 oF). Offline analysis of liquid and vapor fuel samples indicated fuel decomposition via typical pyrolytic reaction pathways. The liquid analysis showed conversion of parent fuel components with formation of unsaturates (aromatics and alkenes) and smaller alkanes. The gaseous products consisted of predominantly C1-C3 alkanes and alkenes (gt; 75% of total vapor yield) with moderate amounts of hydrogen and C4-C6 alkanes and alkenes. The components that were present in the stressed fuel samples were more detonable and could be linked to improved PDE performance. The ignition time decreased by over 20% as temperature increased from 820 K (1016 oF) to 935 K (1224 oF) and by more than 30% when compared to unreacted (flash vaporized) JP-8.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Investigation of the Performance Characteristics of Re-Entry Vehicles
When a non-US spacecraft reenters the Earth's atmosphere, having the ability to accurately determine its performance characteristics is a primary concern. This study investigated the atmospheric re-entry profiles of a maneuverable re-entry vehicle. The re-entry vehicle was modeled as a point mass with aerodynamic properties. Equations of motion were numerically integrated, giving the time histories of position, velocity and flight path angle. The algorithm is able to generate a complete and feasible entry trajectory of approximately 25-minute flight time in about 5 to 10 seconds on a desktop computer, given the entry conditions and values of constraint parameters. This preliminary study shows the feasibility of identifying and further exploring the technical challenges involved in using a mathematical model to simulate the performance characteristics of the maneuvering re-entry vehicle.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Weight Analysis of Two-Stage-To-Orbit Reusable Launch Vehicles for Military Applications
In response to Department of Defense (DoD) requirements for responsive and low-cost space access, this design study provides an objective empty weight analysis of potential reusable launch vehicle (RLV) configurations. Each two-stage-to-orbit (TSTO) RLV has a fixed payload requirement of 20,000 lbf to low Earth orbit. The propulsion systems considered in this study include pure rocket, pure turbine, rocket-based-combined-cycle (RBCC), and turbine-based-combined-cycle (TBCC). The hydrocarbon dual-mode scramjet (DMSJ) engines used in the RBCC and TBCC propulsion systems represent possible applications of the current research being performed in the U.S. Air Force HyTech program. Two sensitivity analyses were then performed on areas of interest directly affecting the propulsion systems in this study, including the effects of orbiter fuel selection, as well as the effects of increasing the turbine installed thrust to weight ratios for the RLVs utilizing afterburning turbine engines. The vertical-takeoff-horizontal-landing (VTHL) RLVs have an empty weight advantage over the horizontal-takeoff-horizontal-landing (HTHL) RLVs. The orbiter propellant switch has either negligible or no empty weight savings for the VTHL RLVs, while it leads to substantial empty weight savings for the HTHL RLVs. For the HTHL RLVs, increasing the turbine installed thrust to weight ratio causes a significant decrease in empty weight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
AFIT UAV Swarm Mission Planning and Simulation System
The purpose of this research is to design and implement a comprehensive mission planning system for swarms of autonomous aerial vehicles. The system integrates several problem domains including path planning, vehicle routing, and swarm behavior. The developed system consists of a parallel, multi-objective evolutionary algorithm-based path planner, a genetic algorithm-based vehicle router, and a parallel UAV swarm simulator. Both the path planner and the UAV swarm simulator are developed on AFIT's Beowulf parallel computer clusters. An extensive set of tests are performed to validate the system components as well as the system integration. Tests focus on two primary objectives: efficiency and effectiveness. The simulator is interfaced with a visualization system that serves as both an iterative design tool and as a mission playback tool. As a design tool, the visualization system provides rapid feedback, allowing developers to quickly observe the effects of model changes on its behavior. As a mission playback tool, decision makers and mission planners can view mission scenarios played out with different sets of parameters. Novel aspects of this research include: integrating terrain following technology into a swarm model as a means of detection avoidance, combining practical problems of path planning and routing into a comprehensive mission planning strategy, and the development of a swarm behavior model with path following capabilities. The culmination of this effort is the development of an extensible developmental model for swarm behavior. Discussions on the of the system's capabilities and limitations are presented along with recommendation for further development.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Effects of Moisture Content in Solid Waste Landfills
Solid waste landfills are an extremely complex and heterogeneous environment. Modeling the biodegradation processes within a landfill must involve an understanding of how environmental factors affect these processes. Arguably, the most important environmental factor influencing biodegradation processes is solid waste moisture content. This thesis effort, which is an extension of a system dynamics model previously presented by Colborn (1997) and amended by Benter (1999), attempts to understand and model the effects of moisture content on waste degradation and landfill gas generation. The new moisture structure that was added to the previous models provides a better representation of the impact of moisture on aerobic and anaerobic hydrolysis and bacterial populations, and ultimately, gas generation. It also gives a clearer picture of how moisture is distributed between the solid waste and the void spaces within a landfill. Leachate and moisture infiltration flows were introduced into the model as a means to replicate the "wet-cell" or bioreactor landfill.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Common Aero Vehicle Autonomous Reentry Trajectory Optimization Satisfying Waypoint and No-Fly Zone Constraints
To support the Global Strike mission, an autonomous trajectory optimization technique is presented to minimize the flight time, satisfy terminal and intermediate constraints, and remain within the specified vehicle heating and control limitations. "Waypoints" are specified for reconnaissance or multiple payload deployments and "no-fly zones" are specified for geopolitical restrictions or threat avoidance. The Hypersonic Cruise Vehicle (HCV) is used as a simplified two-dimensional platform to compare multiple solution techniques. The solution techniques include a unique geometric approach, an analytical dynamic optimization technique, and a numerical approach. This numerical technique is a direct solution method involving pseudospectral methods and nonlinear programming to converge to the optimal solution. The Common Aero Vehicle (CAV) is used as the test platform for the full three-dimensional reentry trajectory optimization problem. The culmination of this research is the verification of the optimality of this proposed numerical technique, as shown for both the two-dimensional and three-dimensional models. Lastly, user implementation strategies are presented to improve accuracy and enhance solution convergence.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Characterization of UAV Performance and Development of a Formation Flight Controller for Multiple Small UAVS
The Air Force Institute of Technology's (AFIT) Advanced Navigation Technology (ANT) Center has recently delved into the research topic of small Unmanned Aerial Vehicles (UAV). One area of particular interest is using multiple small UAVs cooperatively to improve mission efficiency, as well as perform missions that couldn't be performed using vehicles independently. However, many of these missions require that the UAVs operate in close proximity with each other. This research lays the foundation required to use the ANT Center's UAVs for multi-vehicle missions (e.g. cooperatively) by accomplishing two major goals. First, it develops test procedures that can be used to characterize the tracking performance of a small UAV being controlled by a waypoint guided autopilot. This defines the size of the safety zones that must be maintained around each vehicle to ensure no collisions, assuming no, as yet unspecified, collision avoidance algorithm is being implemented. Secondly, a formation flight algorithm is developed that can be used to guide UAVs relative to each other using a waypoint guided autopilot. This is done by dynamically changing the waypoints. Such an approach gives a wrap-around method of cooperatively controlling UAVs that can only be guided waypoint-to-waypoint. For both components of this research, tests were conducted using a hardware-in-the-loop (HITL) simulation before validating through flight testing. This report, along with legacy documentation and procedures, furthers the UAV test bed at AFIT and establishes methods for simulating, visualizing, and flight testing multiple UAVs during formation/cooperative flight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Detonation Propagation Through Ducts in a Pulsed Detonation Engine
Development of a continuously operating pulsed detonation engine (PDE) without a high energy ignition system or a deflagration-to- detonation transition (DDT) device will increase engine efficiency, reduce cost, improve performance, and reduce weight. This report is a study of configurations that allow a consistent and predictable transition of a detonation from one detonation tube to second tube. The intent was, via visualization of detonation propagation through a cross-over tube, to develop a cross-over passage leading to minimization of energy losses and effective and repeatable tube-to-tube initiation. Detonation tube cross-over width, cross-over geometry and fuels were varied to determine their effect on tube-to-tube detonation initiation. The cross-over detonations studied decoupled into and out of the cross-over tube due to propagation as subcritical spherical detonations. It was shown that the mechanism of shock reflection could be used to transition the spherical detonation back to a planar detonation.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Comparative Analysis of a High Bypass Turbofan Using a Pulsed Detonation Combustor
It has been proposed that the implementation of a pulsed detonation combustor in a high-bypass turbofan engine would result in an engine that is both more efficient and more reliable. The validity of the performance claims are evaluated based on a comparison between the baseline and hybrid turbofans as modeled in the Numerical Propulsion System Simulation (NPSS). The engine cycle of the baseline high-bypass turbofan is evaluated and compared using both the Aircraft Engine Design System (AEDsys) and NPSS programs. The baseline engine agreed to within 1% on the net thrust calculation and specific fuel consumption between the two programs. Differences are traceable to the variation in specific heat models and to different methods of calculating temperature across the turbine and compressor components. The hybrid pulsed detonation engine model shares a common architecture with the baseline turbofan model. Inlet mass flow and core mass flow are maintained, but the combustor of the baseline engine is replaced with a pulsed detonation combustor for the hybrid engine. The effect of detonation on the core airflow is calculated using a closed form solution of the Chapman-Jouguet Mach number with a total energy correction applied. Cycle time is calculated to provide a reasonable estimate of frequency for the user input geometry. Effects of sub-component design choices within the pulsed detonation combustor are evaluated using simple parametric studies. These studies are used to select an optimal architecture for the combustor. The effects of detonation are accounted for by applying pressure and temperature losses to the fluid exiting the combustor. A parametric study was performed to demonstrate what level of loss continues to yield a more efficient engine. Results show improvement in thrust specific fuel consumption with careful selection of combustor design parameters. There is a definite level of acceptable loss that if surpassed makes pulsed detonation combustion a goodThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Analyzing Carbohydrate-Based Regenerative Fuel Cells as a Power Source for Unmanned Aerial Vehicles
Based on current capabilities, we examine the feasibility of creating a carbohydratebased regenerative fuel cell (CRFC) as the primary power source for unmanned aerial vehicles (UAV) for long endurance missions where station keeping is required. A CRFC power system is based on a closed-loop construct where carbohydrates are generated from zooxanthellae, algae that create excess carbohydrates during photosynthesis. The carbohydrates are then fed to a carbohydrate fuel cell where electric power is generated for the UAV's propulsion, flight control, payload, and accessory systems. The waste products from the fuel cell are used by the zooxanthellae to create more carbohydrates, therefore mass is conserved in the process of power generation. The overall goal of this research is to determine if CRFCs should be explored further as a viable power source. Through simulations, a UAV is sized to determine if greater than 24 hour endurance flight is possible and these results are compared to UAVs using more traditional photocell based power systems. The initial results suggest that more research should be done in the development of CRFCs as a power system for long endurance UAVs. The final outcome of this research is to identify the most important areas for more detailed followon work in designing a production-ready CRFC power system for long endurance UAVs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Aeroelastic Analysis of a Joined-Wing Sensorcraft
This study performed an aeroelastic analysis of a joined-wing SensorCraft. The analysis was completed using an aluminum structural model that was splined to an aerodynamic panel model. The force and pressure distributions were examined for the four aerodynamic panels: aft wing, fore wing, joint, and outboard tip. Both distributions provide the expected results (elliptical distribution), with the exception of the fore wing. The fore wing appears to be affected by interference with the joint. The use of control surfaces for lift and roll was analyzed. Control surfaces were effective throughout most of the flight profile, but may not be usable due to radar requirements. The aft wing was examined for use in trimming the vehicle. Also, two gust conditions were examined. In one model, the wing twist was simulated using a series of scheduled control surfaces. Trim results (angle of attack and twist angle) were compared to those of previous studies, including gust conditions. The results are relatively consistent with those calculated in previous studies, with variations due to differences in the aerodynamic modeling. To examine a more physically accurate representation of aft wing twist, it was also modeled by twisting the wing at the root. The twist was then carried through the aft wing by the structure. Trim results were again compared to previous studies. While consistent for angle of attack results, the aft wing twist deflection remained relatively constant throughout the flight profile and requires further study.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Detonation Branching in a PDE With Liquid Hydrocarbon Fuel
Pulse detonation engines (PDE) capitalize on the large mass flux and pressure rise a detonation has compared to a deflagration. The PDE operates on a fill-detonate-exhaust cycle and its thrust is directly proportional to the cycle frequency, therefore a decrease in cycle time results in increased thrust. This research showed that the detonate part of the cycle can be shortened by using a branched detonation as the ignition source as opposed to standard spark ignition. This research was a milestone in PDE development because, while detonation branching has been accomplished using gaseous hydrogen as the fuel, this was the first instance of detonation branching using liquid hydrocarbon fuel. A vaporization system was used to vaporize the fuel and mix it with the airstream, allowing the PDE to operate at stoichiometric conditions. This research concluded that detonation ignition is not only possible when using liquid hydrocarbon fuel, but it produces results superior to those obtained using spark ignition. With detonation ignition, more energy is input into the head than with spark ignition. Operating at a 20 Hz cycle frequency and a 1.02 equivalence ratio, ignition times were 5.63 and 0.19 ms and deflagration to detonation transition (DDT) times were 2.36 and 1.03 ms for the spark- and detonation-ignited thrust tubes, respectively. The total time savings in the detonate part of the PDE cycle for detonation-ignition was 6.77 ms, an 85% time reduction in ignition and DDT times. This reduction in cycle time affords an appreciable thrust increase. Also, DDT was complete in 83% of the distance, allowing a decrease in tube length, which decreases overall weight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Handling Qualities Evaluation of a Supersonic Tailless Air Vehicle
This thesis presents the results of a handling qualities evaluation of a supersonic tailless air vehicle. The 2006 Quadrennial Defense Review mandated the need for the next generation of long-range strike aircraft by 2018. Due to speed and stealth requirements, this resulted in a tailless aircraft with an instantaneous center of rotation located well forward of that of a conventional aircraft. This thesis examines how this center of rotation affected pilot handling qualities ratings. This effect should have been the most pronounced during approach and landing, and was where the testing focused. The goal of this research was to develop a systematic procedure for evaluating the handling qualities of this aircraft, and to determine how different pilot flying techniques or pilot-inceptor interactions influenced them. This procedure was demonstrated in simulator testing and in flight testing on the Calspan-operated Total In-Flight Simulator aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Multimission Aircraft Design Study, Payload
It is proposed that a Multi-Mission Aircraft (MMA) be prepared to combine some or all the functions of the aging AWACS, JSTARS, RIVET JOINT, COMPASS CALL, and ABCCC fleet. Three different thesis studies have been developed by three Air Force Institute of Technology GSE students to show the feasibility of replacing the current aging fleet with one or more MMA platforms. This is the thesis in which the payload issues have been examined. Within this thesis, two different alternative architectures, which are One Tail Number and Different Tail Numbers including nine different configurations, have been considered. Estimated payload characteristics of these alternatives have been compared to those of Boeing 767-400ER, which is the aircraft selected as the baseline for MMA platform. Reduced life cycle cost, increased measure of aircraft specifications, and minimum risk are the main objectives pursued by means of several systems engineering and aircraft design methodologies.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Flight Test and Handling Qualities Analysis of a Longitudinal Flight Control System Using Multiobjective Techniques
This thesis addresses the application of optimal, multiobjective control theory control theory to flight control design for the approach and landing phase of flight. Five flight control systems were designed using classical, H2, H?, and Mixed H2/H? methods. The MATLAB" MUTOOLS" and AFIT MXTOOLS toolboxes were used to produce the optimal, multiobjective designs. These designs were implemented for flight test on the Calspan VSS I Learjet, simulating the unstable longitudinal dynamics of an F-16 type aircraft. A limited handling qualities investigation was performed. Model following was used in the design phase to meet handling qualities specifications. The designs were successfully implemented and verified on the Calspan Learjet prior to flight test. An unmodeled aircraft mode was discovered just prior to flight test that made three of the designs slightly unstable. However, all of the designs achieved Level II or better Cooper-Harper handling qualities ratings for the landing tasks performed illustrating that the optimal multiobjective methods used can give acceptable or better handling qualities.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design and Performance Calculations of a Propeller for Very High Altitude Flight
Reported here is a design study of a propeller for a vehicle capable of subsonic flight in Earth's stratosphere. All propellers presented were required to absorb 63.4 kW (85 hp) at 25.9 km (85,000 ft) while aircraft cruise velocity was maintained at Mach 0.40. To produce the final design, classic momentum and blade-element theories were combined with two and three-dimensional results from the Advanced Ducted Propfan Analysis Code (ADPAC), a numerical Navier-Stokes analysis code. The Eppler 387 airfoil was used for each of the constant section propeller designs compared. Experimental data from the Langley Low-Turbulence Pressure Tunnel was used in the strip theory design and analysis programs written. The experimental data was also used to validate ADPAC at a Reynolds numbers of 60,000 and a Mach number of 0.20. Experimental and calculated surface pressure coefficients are compared for a range of angles of attack. Since low Reynolds number transonic experimental data was unavailable, ADPAC was used to generate two-dimensional section performance predictions for Reynolds numbers of 60,000 and 100,000 and Mach numbers ranging from 0.45 to 0.75. Surface pressure coefficients are presented for selected angles of attack. in addition to the variation of lift and drag coefficients at each flow condition. A three-dimensional model of the final design was made which ADPAC used to calculated propeller performance. ADPAC performance predictions were compared with strip-theory calculations at design point. Propeller efficiency predicted by ADPAC was within 1.5% of that calculated by strip theory methods, although ADPAC predictions of thrust, power, and torque coefficients were approximately 5% lower than the strip theory results. Simplifying assumptions made in the strip theory account for the differences seen.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Decision-Aiding and Optimization for Vertical Navigation of Long-Haul Aircraft
Most decisions made in the cockpit are related to safety, and have therefore been proceduralized in order to reduce risk. There are very few which are made on the basis of a value metric such as economic cost. One which can be shown to be value based, however, is the selection of a flight profile. Fuel consumption and flight time both have a substantial effect on aircraft operating cost, but they cannot be minimized simultaneously. In addition, winds, turbulence, and performance vary widely with altitude and time. These factors make it important and difficult for pilots to (a) evaluate the outcomes associated with a particular trajectory before it is flown and (b) decide among possible trajectories. The two elements of this problem considered here are: (1) determining what constitutes optimality, and (2) finding optimal trajectories. Pilots and dispatchers from major u.s. airlines were surveyed to determine which attributes of the outcome of a flight they considered the most important. Avoiding turbulence-for passenger comfort-topped the list of items which were not safety related. Pilots' decision making about the selection of flight profile on the basis of flight time, fuel burn, and exposure to turbulence was then observed. Of the several behavioral and prescriptive decision models invoked to explain the pilots' choices, utility maximization is shown to best reproduce the pilots' decisions. After considering more traditional methods for optimizing trajectories, a novel method is developed using a genetic algorithm (GA) operating on a discrete representation of the trajectory search space. The representation is a sequence of command altitudes, and was chosen to be compatible with the constraints imposed by Air Traffic Control, and with the training given to pilots. Since trajectory evaluation for the GA is performed holistically, a wide class of objective functions can be optimized easily.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Disturbance Observer
A new flight controller was evaluated through piloted simulation and flight test conducted at the USAF Test Pilot School. The controller, commonly called a disturbance observer, uses inertial sensor feedback routed through a simple control architecture that acts to force the desired response while rejecting sensor noise and atmospheric disturbances. The investigation included both handling qualities testing in the Octonian simulator at the Air Force Research Laboratories Air Vehicle Directorate, and initial flight test conducted as part of a Test Management Project at the USAF TPS. Simulation produced positive results with desired performance throughout a wide flight envelope. In addition, the desired response of the aircraft was easily modified by changing variables within the controller. Flight test was conducted on the Variable-stability In-flight Simulator and Test Aircraft (VISTA). Twelve test sorties totaling 16.4 flight hours were conducted and culminated in multiple landings at Edwards AFB, CA. Time delay inherent in the VISTA resulted in the requirement to gain down the control surface command signal. Sensor noise was amplified and caused a control surface 'buzz." Flying qualities exhibited lower damping and frequency than 'desired' yet were consistent throughout a larger flight envelope. Post flight analysis resulted in the determination of ways to reduce the noise causing the 'buzz' and improve the flying qualities by adjusting the controller's 'desired dynamics.'This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Isomer Heat Exchanger Combustor Replacement for a Supersonic Ramjet Powered Vehicle
This study investigated the possibility of utilizing a Triggered Isomer Heat Exchanger (TIHE) within a ramjet engine to power a supersonic Conventional Air Launched Cruise Missile (CALCM). A computational ramjet engine was created using engine analysis software. This model was then run through a simulated cruise missile mission using AEDsys, a mission analysis and engine performance software suite. The replacement of the combustor with a TIHE led to an impressive range increase for the supersonic cruise missile.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Century Long Pursuit of Alternative Fuels and Feedstocks
The United States has dramatically increased its production of alternative fuels over the past seven years. With the passing of the Energy Independence and Security Act of 2007 (EISA), alternative fuel production will increase in the United States over 700% from 2005 levels. However, the pursuit of petroleum alternatives is not a recent trend. Over the last 100 years, various nations have pursued petroleum alternatives with varying levels of success. This research focuses on the historical development of 10 leading alternative fuels and feedstocks. Through a thorough literature review we will identify commonalities among these fuels and feedstocks which have hindered their adoption. Further, the research evaluates the 10 alternative fuels and feedstocks with text mining software to support findings from the literature review. This research finds that alternative fuels face significant challenges with regards to environmental impacts, technological maturity, and societal costs. Further, these petroleum alternatives have rarely been economical solutions. The research findings suggest that while there are National Security reasons for pursuing petroleum alternatives, rarely are there economic ones.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design Manual Constructed Wetlands and Aquatic Plant Systems for Municipal Wastewater Treatment
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Corrosion Manual for Internal Corrosion of Water Distribution Systems
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Systems Architecture and Advanced Sensors Application for Real-Time Aircraft Structural Health Monitoring
Aircraft are being pushed beyond their original service life, increasing the potential for structural failures. A catastrophic in flight failure of an F-15 bulkhead and severe cracking in the C-130 Wing rainbow fitting are two recent examples that have caused major problems for the Air Force. Previous Aircraft Structural Health Monitoring Systems research primarily explored using a system during the ground maintenance phase. This research will explore a Real-Time Aircraft Structural Health Monitoring System (RTASHMS) that includes a ground phase as well as an in-flight phase. The RTASHMS will continuously analyze structural hot spots, detect critical structural damage or cracks and will alert pilots and maintainers of potential trouble before a catastrophic structural failure. Current sensor technology has limited the construction and use of a reliable aircraft structural health monitoring system. This research will compare the capabilities of current sensor technology with the capabilities of a new cutting edge sensor. The new sensor shows promise in advancing a reliable RTASHMS from theory to reality. This technology was validated in Aluminum Dog Bone specimens and Composite Lap Joint with nano-adhesivesThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Identifying and Mitigating the Risks of Cockpit Automation
Cockpit automation has delivered many promised benefits such as improved system safety and efficiency, however, at the same time it has imposed system costs that are often manifest in the forms of mode confusion, errors of omission, and automation surprises. An understanding of the nature of these costs as well as associated influencing factors is necessary to adequately design the future automated systems that will be required for Air Mobility Command aircraft to operate in the future air traffic environment. This paper reviews and synthesizes Human Factors research on the costs of cockpit automation. These results are interpreted by modeling the automated cockpit as a supervisory control system in which the pilot works with, but is not replaced by, automated systems. From this viewpoint, pilot roles in the automated cockpit provide new opportunities for error in instructing, monitoring, and intervening in automated systems behavior. These opportunities for error are exacerbated by the limited machine coordination capabilities, limits on human coordination capabilities and properties of machine systems that place new attention and knowledge demands on the human operator. In order to mitigate the risks posed by these known opportunities for error and associated influencing factors, a system of defenses in depth is required involving integrated innovations in design, procedures, and training. The issues raised in this paper are not specific to transport aircraft or the broader aviation domain, but apply to all current and future highly automated military systems.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Flexible Twist for Pitch Control in a High Altitude Long Endurance Aircraft With Nonlinear Response
The goal was to demonstrate that scaling the nonlinear response of a full-scale finite element model of a high-altitude long-endurance (HALE) aircraft was possible if the model was aeroelastically and "nonlinearly" scaled. A straight-forward method of scaling the first three natural vibration frequencies and mode shapes, and the first buckling eigenvalue was attempted. In addition to analytical scaling several experiments were accomplished to understand and overcome design challenges of HALE aircraft. One such challenge is combated by eliminating pitch control surfaces and replacing them with an aft-wing twist concept. This design was physically realized through wind tunnel measurement of forces, moments and pressures on a subscale experimental model proving that pitch control with aft-wing twist is feasible. Another challenge is predicting the nonlinear response of long-endurance aircraft. This was addressed by experimental validation of modeling nonlinear response on a subscale experimental model. The validation accomplished during this experiment on a subscale model will reduce technical risk for full-scale development of such pioneering craft. Nonlinearities can be attributed to follower forces, which were found to be a significant influence in HALE aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Fixed-Wing Aircraft Combat Survivability Analysis for Operation Enduring Freedom and Operation Iraqi Freedom
The primary tenet of the aircraft survivability discipline is threat definition. In order to deliver relevant capabilities and protection to the warfighter it is imperative; therefore, to provide timely, accurate, and actionable threat data to the survivability community. In an attempt to identify the evolution of aircraft threats in today's combat environment, an analysis of fixed-wing aircraft battle damage was conducted. This analysis reports battle damage incidents from OPERATIONS ENDURING FREEDOM (OEF) and IRAQI FREEDOM(OIF). Additionally, reported damage incidents were then validated by crosschecking aircraft maintenance records from this period to eliminate non-hostile fire data points. This revolutionary approach uncovered discontinuities, which were further explored to identify their root cause. As a result, significant Air Force policy changes in the realm of battle damage reporting procedures were suggested. In the end, lives will be saved because the acquisition community at large will have valuable threat data in which they can be confident.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Flapping Wing Micro Air Vehicle Wing Manufacture and Force Testing
Numerous wing manufacturing techniques have been developed by various universities for research on Flapping Wing Micro Air Vehicles. Minimal attention though is given to repeatability of wing aerodynamics and dynamic response, which is crucial to avoid asymmetric flapping. Thus the focus of this research becomes twofold. First, repeatable wing manufacturing techniques are developed to ensure flapping wings have similar aerodynamic and dynamic characteristics. For this purpose, four wing designs were selected to not only test the aerodynamics of the different designs, but to also validate manufacturing techniques. The various wing designs are assessed using two methods: dynamic and aerodynamic data. Dynamic data, specifically the wing's structural dynamic response, is measured using a 3D laser vibrometer. From this vibration data, the wings natural frequency modes can be determined which should correlate strongly within the various wing designs if the manufacturing techniques are repeatable. Next, using a piezoelectric flapping actuator, the four wing designs are flapped with force data collected. This data is then used to determine the aerodynamic characteristics of each wing. From the two methods of wing evaluation, it was found that the wings manufactured using a three-layer carbon layup showed greater structural dynamic modal repeatability as compared to one-layer carbon wings. Additionally, Wing Design 3 flapped with the most efficiency with a significantly higher lift to drag ratio as compared to the other wing designs. From this research, the wing manufacturing techniques are quantitatively shown to be repeatable while an optimal wing design based on the maximum lift-to-drag ratio is found which can be used for future research.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Satellite Attitude Control Using Atmospheric Drag
Attitude control is a requirement for most satellites. Many schemes have been devised over the years including control moment gyros, reaction wheels, spin stabi- lization and gravity gradient stabilization. For low Earth orbits, the Earth's atmo- sphere can have an affect on a satellite's orbit and attitude. Using the atmosphere to control spacecraft attitude has been researched in the past however very little re- search has been done using an active feedback control system to maintain spacecraft attitude. This research effort examines the feasibility of using the atmosphere to actively control a spacecraft's attitude using drag panels. Several variables affect the drag force, of which, projected area is the only variable that can be changed easily. Adding controllable drag panels to a satellite gives the ability to change the projected area as well as the location of the projected area. The result of manipulating the projected areas is a force that is not aligned with the center of gravity, resulting in an external torque on the spacecraft. Although these torques are very small, on the scale of micro-Newton meters and smaller, over time these torques can be used to change the spacecraft's attitude. A linear computer model was created using a proportional controller. This model was used to evaluate the effectiveness of using drag panels for attitude control. Results from the simulation show that the spacecraft can recover from disturbance torques that may cause a change in attitude very effectively especially at low altitudes (200-300km).This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Exfit Flight Design and Structural Modeling for Falcon LAUNCH VIII Sounding Rocket
This research effort furthers the Air Force's study of reusable launch vehicles and hypersonic airfoils by conducting a hypersonic flight test using the US Air Force Academy's Falcon LAUNCH VIII sounding rocket. In this study, two experimental fin tips were designed and attached to the sounding rocket in place of two stabilizer fins in order to collect data throughout the rocket's hypersonic flight profile. The desire to research, study, and test experimental fin tips was driven by the Air Force Research Laboratory's Future responsive Access to Space Technologies (FAST) program and their desire to include vertical stabilizers on the wing tips of reusable launch vehicles (RLVs). In this research study, finite element models of the experimental fin tips were developed and used to predict the flight data collected by the strain and temperature gages attached to the test specimen. The results of these flight prediction tests showed that the test specimen will undergo the greatest deflection and strain during the acceleration of the rocket. Maximum deflection and strain gage readings were obtained at a speed of Mach 2.5 at an altitude of 9k feet. Ultimately, the payload will undergo a maximum deflection of 0.6 inches at the fin tip and a maximum strain gage reading of 0.00122 on the main wing section of the payload.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modeling of Wake-vortex Aircraft Encounters
There are more people passing through the world's airports today than at any other time in history. With this increase in civil transport, airports are becoming capacity limited. In order to increase capacity and thus meet the demands of the flying public, the number of runways and number of flights per runway must be increased. In response to the demand, the National Aeronautics and Space Administration (NASA), in conjunction with the Federal Aviation Administration (FAA), airport operators, and the airline industry are taking steps to increase airport capacity without jeopardizing safety. Increasing the production per runway increases the likelihood that an aircraft will encounter the trailing wake-vortex of another aircraft. The hazard of a wake-vortex encounter is that heavy load aircraft can produce high intensity wake turbulence, through the development of its wing-tip vortices. A smaller aircraft following in the wake of the heavy load aircraft will experience redistribution of its aerodynamic load. This creates a safety hazard for the smaller aircraft. Understanding this load redistribution is of great importance, particularly during landing and take-off. In this research wake-vortex effects on an encountering 10% scale model of the B737-100 aircraft are modeled using both strip theory and vortex-lattice modeling methods. The models are then compared to wind tunnel data that was taken in the 30ft x 60ft wind tunnel at NASA Langley Research Center (LaRC). Comparisons are made to determine if the models will have acceptable accuracy when parts of the geometry are removed, such as the horizontal stabilizer and the vertical tail. A sensitivity analysis was also performed to observe how accurately the models could match the experimental data if there was a 10% error in the circulation strength. It was determined that both models show accurate results when the wing, horizontal stabilizer, and vertical tail were a part of the geometry. When the horizontal stabilizThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Systems Engineering Approach to Integrated Structural Health Monitoring for Aging Aircraft
The United States Air Force and many of its Coalition partners have extended the original service life of some of their aging aircraft due to fiscal constraints. This life extension often requires increased periodic and in-depth inspections, increasing maintenance costs and resulting in longer periods of aircraft downtime. An integrated structural health monitoring system (ISHMS) for aging aircraft may reduce the cur- rent inspection burden, and thus decrease costs and system downtime. This thesis developed a generic systems engineering process to describe the system definition for an ISHMS installed on a non-specific aging aircraft. The system definition developed in this thesis followed the Vee Model for systems development and serves as a starting point for future research and/or development efforts in this field. User analysis, user requirements, system requirements, and some Department of Defense Architecture Framework system architectures formed the basis for the generic systems engineering process presented. Furthermore, mathematical simulations compared the failure rate and number of inspections for a scenario without an ISHMS to a scenario with an ISHMS. This simplified analysis demonstrated that a structural health monitoring system for aging aircraft may have promising benefits with respect to both safety improvements and decreased maintenance costs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Novel Communications Protocol Using Geographic Routing for Swarming UAVs Performing a Search Mission
This research develops the UAV Search Mission Protocol (USMP) for swarming UAVs and determines the protocol's effect on search mission performance. It is hypothesized that geographically routing USMP messages improves search performance by providing geography-dependent data to locations where it impacts search decisions. It is also proposed that the swarm can use data collected by the geographic routing protocol to accurately determine UAV locations and avoid sending explicit location updates. The hypothesis is tested by developing several USMP designs that are combined with the Greedy Perimeter Stateless Routing (GPSR) protocol and a search mission swarm logic into a single network simulation. The test designs use various transmission power levels, sensor types and swarm sizes. The simulation collects performance metrics for each scenario, including measures of distance traveled, UAV direction changes, number of searches and search concentration. USMP significantly improves mission performance over scenarios without inter-UAV communication. However, protocol designs that simply broadcast messages improve search performance by 83% in total searches and 20% in distance traveled compared to geographic routing candidates. Additionally, sending explicit location updates generates 3%-6% better performance per metric versus harvesting GPSR's location information.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Thermal Characterization of a Hall Effect Thruster
The thermal characteristics of a Hall thruster directly influence thruster and spacecraft design. High temperatures affect the magnetic coil capabilities and cause higher insulator erosion rates, influencing both thruster performance and lifetime. The Hall thruster transfers heat through both radiation and conduction, and the spacecraft must handle this additional thermal energy. An infrared camera provides a non-intrusive method to analyze the thermal characteristics of an operational Hall thruster. This thesis contains the thermal analysis of a Busek Co. Inc. 200 W Hall thruster, using a FLIR ThermaCAM SC640 infrared camera. The Space Propulsion Analysis and System Simulator Laboratory at the Air Force Institute of Technology on Wright-Patterson Air Force Base provided the location for thruster set up and operation. The infrared camera furnishes the surface temperatures for the entire thruster, and approximates the transient heating behavior during start up, steady state, and shut down. Thermocouples verify and correct the camera data. Experimentally determined emissivities characterize the materials of the thruster. In addition, a view factor analysis between the camera pixels and the alumina sprayed portion of the cathode determines the exchange of radiation between the pixels and cathode surface. This process develops a technique to map surface temperatures of complex geometries with confidence in the actual values. Accurately mapping the surface temperatures of a Hall Effect thruster will improve both thruster efficiency and lifetime, and predict the thruster's thermal load on a satellite.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
