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Articles 1 - 14 of 14
Full-Text Articles in Engineering
F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning
F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning
Theses and Dissertations
Buffet-induced vibrations can have a disastrous impact on aircraft structures. Early attempts at combating buffet vibrations included passive methods such as structural enhancements and leading edge fences. Active methods have shown greater promise, including active airflow control, control surface modulation, and active structural control using piezoelectric actuators. Surface mounted piezoelectric actuators impart directional strain reducing the negative effects associated with harmful vibration. The Block-15 F-16 ventral fin represents an aircraft structure prone to failure when subjected to the buffet field from the wake of a LANTIRN pod. This research takes advantage of the susceptibility to buffet vibration of the Block …
Effects Of Duty Schedule Variance And Overtime On The Job Satisfaction And Turnover Intentions Of Usaf F-16 Crew Chiefs, Michael J. Shellhamer
Effects Of Duty Schedule Variance And Overtime On The Job Satisfaction And Turnover Intentions Of Usaf F-16 Crew Chiefs, Michael J. Shellhamer
Theses and Dissertations
This thesis empirically assessed how duty schedule variance and overtime affect the job satisfaction and turnover intentions of USAF F-16 crew chiefs. A survey was completed by 346 active duty USAF F-16 crew chiefs regarding their perceptions of duty schedule variance, overtime, job satisfaction and intent to leave the Air Force. Theory suggests that turnover behavior is a multistage process that involves organizational, individual, and attitudinal components. Using multivariate correlation and regression analyses, plausible evidence was found to support the idea that duty schedule variance and overtime plays a role in USAF F-16 crew chief turnover intentions via job satisfaction. …
Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth
Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth
Theses and Dissertations
Wing flutter, or more accurately limit cycle oscillation (LCO), has been an issue for the F-16 since its operational deployment. Different store configurations and the permutations of those configurations after weapons are released will cause LCO to either disappear or appear. Unfortunately, the current method used by engineers for predicting LCO onset is based on linear, subsonic aerodynamic theory with no corrections for transonic effects. Predictions using this method are often good in frequency, but can be far off in predicting onset speed, forcing flutter engineers to rely more on experience and interpolation from similar configurations to design flight test …
Calculation Of The Actual Cost Of Engine Maintenance, Oguz Ezik
Calculation Of The Actual Cost Of Engine Maintenance, Oguz Ezik
Theses and Dissertations
The cost of military operations has been difficult to determine, yet considered of high importance. The cost of an operation is largely dependent upon the answers to subordinate questions involving the discrete costs of military activities, like supporting individual items, While different cost estimates have received attention from the media, the question arises as to how accurate these figures are, There have been numerous studies performed by the Operations Research analysts to minimize costs while allocating scarce resources, However, the values of these studies are dependent upon whether or not the cost figures used are sufficiently "true" or accurate, This …
Forecasting Readiness: Using Regression To Predict The Mission Capability Of Air Force F-16 Fighter Aircraft, Steven A. Oliver
Forecasting Readiness: Using Regression To Predict The Mission Capability Of Air Force F-16 Fighter Aircraft, Steven A. Oliver
Theses and Dissertations
According to many, the readiness of America's forces deteriorated in the 1990s. In the Air Force, the combat readiness of its fighter aircraft has declined. One of its indicators of combat readiness, the mission capable rate, is used to identify the percentage of aircraft unable to perform their missions. From FY94-FY98, the aggregate total not mission capable rate for maintenance steadily increased from 14% to 18.2% while total not mission capable rate for supply increased from 5.5% to 17.5% between FY86 and FY00. The USAF uses the funding/Availability Multi-Method Allocator for Spares model to forecast these rates for its aircraft. …
Aerospace Ground Equipment's Impact On Aircraft Availability And Deployment, Jeffrey D. Havlicek
Aerospace Ground Equipment's Impact On Aircraft Availability And Deployment, Jeffrey D. Havlicek
Theses and Dissertations
The first purpose of this thesis was to study the effects of four factors on aircraft availability: the aerospace ground equipment (AGE) design configuration, the mean time between failure (MTBF) of AGE, the mean time to repair (MTTR) AGE, and the travel time to transport the AGE around the flightline. A simulation developed by Carrico (1996) that has its foundation based on the Logistics Composite Model (LCOM) was used. ANOVA results indicated that the present estimates of these factors are too broad for trade studies that include an estimate of aircraft availability to begin. The time it takes AGE to …
Multiple Model Adaptive Estimation And Control Redistribution For The Vista F-16, Robert W. Lewis Sr.
Multiple Model Adaptive Estimation And Control Redistribution For The Vista F-16, Robert W. Lewis Sr.
Theses and Dissertations
Performance characteristics of a Multiple Model Adaptive Estimation and Control Redistribution (MMAE/CR) algorithm are evaluated against single and double actuator and sensor failures. MMAE alone can compensate for sensor failures, whereas Control Redistribution compensates for actuator failures by redistributing commands, initially intended for failed actuators, to the unfailed actuators in such a way that the desired system response is achieved. Both failure detection and compensation capabilities are developed and analyzed through an extensive amount of simulation data, particularly addressing multiple failures. Simulations are performed utilizing the high fidelity, non-linear six degree of freedom Simulation Rapid Prototyping Facility for the VISTA …
Comparison Of The Control Anticipation Parameter And The Bandwidth Criterion During The Landing Task, David A. Kivioja
Comparison Of The Control Anticipation Parameter And The Bandwidth Criterion During The Landing Task, David A. Kivioja
Theses and Dissertations
Many handling qualities criteria have been developed which predict pilot opinion of landing aircraft. MIL-STD-1797A, 'Flying Qualities of Piloted Aircraft' lists six different criteria. However, applying all six criteria to one aircraft can lead to conflicting results. The Air Force Institute of Technology (AFIT) along with the Flight Dynamics Laboratory have conducted research to evaluate differences among the handling qualities criteria in MIL-STD-1797A. The overall objective of this thesis was to determine similarities and discrepancies between the Control Anticipation Parameter (CAP) and bandwidth criteria, and to evaluate the advantage of including a dropback criterion with the bandwidth criterion. Results of …
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation And Aerodynamic Control Effector Failures, Vicent J. Cacciatore
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation And Aerodynamic Control Effector Failures, Vicent J. Cacciatore
Theses and Dissertations
Fault tolerant flight control systems for combat aircraft are an alternative to excessively redundant aircraft designs or reconfigurable control laws. However, due to the range of flight conditions within a combat aircraft's operational flight envelope, the variety of its configurations, and the unavailability of an aerodynamic data base for damaged aircraft, designing fault tolerant systems is a complicated endeavor. Quantitative Feedback Theory is a robust control design technique especially well-suited to manage the structured parametric uncertainty inherent in this problem, and consequently is applied as the primary design tool for this research. Furthermore, realistic failure models are developed for the …
Multiple Model Adaptive Control Of The Vista F-16, Michael J. Stepaniak
Multiple Model Adaptive Control Of The Vista F-16, Michael J. Stepaniak
Theses and Dissertations
Multiple model adaptive control (MMAC) is investigated using the high-fidelity, nonlinear, six-degree-of-freedom Simulation Rapid-Prototyping Facility VISTA F-16. Detection of single actuator and sensor failures is considered, with an MMAC algorithm initially pursued which allows a controller specifically designed for each particular failure condition to replace the standard F-16 Block 40 flight control system (FCS) once the failure is detected. The synthesis of certain discrete-time LQG/PI controllers (those using control variables linearly dependent on state derivatives) is shown to be unattainable due to numerical difficulties. A novel control technique, termed control redistribution, is introduced which redistributes control commands (that would normally …
Implementation And Demonstration Of A Multiple Model Adaptive Estimation Failure Detection System For The F-16, Peter K. Eide
Implementation And Demonstration Of A Multiple Model Adaptive Estimation Failure Detection System For The F-16, Peter K. Eide
Theses and Dissertations
A Multiple Model Adaptive Estimation (MMAE) algorithm is implemented with the fully nonlinear six-degree-of-motion, Simulation Rapid-Prototyping Facility (SRF) VISTA F-16 software simulation tool. The algorithm is demonstrated to be capable of identifying flight critical aircraft actuator and sensor failures at a low dynamic pressure (20,000 ft, .4 Mach). Research included single and dual complete failures. Tuning methods for accommodating model mismatch, including addition of discrete dynamics pseudonoise and continuous measurement pseudonoise, are discussed and demonstrated. Scalar residuals within each filter are also examined and characterized for possible use as an additional failure declaration voter. Robustness to sensor failures provided by …
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips
Theses and Dissertations
An aircraft's response to control inputs varies widely throughout its flight envelope. The aircraft configuration also impacts control response through variations in center of gravity and moments of inertia. Designing a flight control system (FCS) to accommodate the full flight envelope and configuration set of an aircraft is clearly a complex undertaking. Quantitative feedback theory (QFT) is a design tool which enables the engineer to attack this task in an efficient way. Although QFT is a robust control design technique, it is an interactive algorithm allowing the engineer full control over compensator order and gain. In this research effort, a …
Life Cycle Costs Of Alternatives For F-16 Printed Circuit Board Diagnosis Equipment, Kent R. Montgomery, Clifford B. Thorstenson
Life Cycle Costs Of Alternatives For F-16 Printed Circuit Board Diagnosis Equipment, Kent R. Montgomery, Clifford B. Thorstenson
Theses and Dissertations
This study analyzes two alternatives for printed circuit board (PCB) diagnosis for the F-16 depot PCB repair shop from a life cycle cost (LCC) perspective. Alternative 1 assumes the use of the current F-16 automatic test equipment (ATE) while Alternative 2 augments the current ATE with infrared imaging test equipment. Infrared imaging is a developed technology that is currently available to the Air Force in a commercial-off-the-shelf (COTS) form. Using the Cost Analysis and Strategy Assessment (CASA) Life Cycle Cost (LCC) Model and data from the DL41 database on F-16 PCBs this study determined that over the current expected life …
Design Of A Subsonic Envelope Flight Control System For The Vista F-16 Using Quantitative Feedback Theory, Odell R. Reynolds
Design Of A Subsonic Envelope Flight Control System For The Vista F-16 Using Quantitative Feedback Theory, Odell R. Reynolds
Theses and Dissertations
A controlled plant's characteristics can vary widely throughout its operational envelope. This is a major problem in nominal plant-based control system design. Hence, gain scheduling is often used for full envelop design. In this paper, it is proposed to address the plant's variability using robust control design concepts. In particular, the frequency domain based Quantitative Feedback Theory Multiple-Input Multiple-Output robust control design method is employed for the synthesis of a full envelop flight control system for an F-16 derivative. Compensators for the aircraft's pitch and lateral directional channels are designed, and the designs are validated using linear simulations.