SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 43, ISSUE 18 - SEPTEMBER 09, 2005
06 AVIONICS AND AIRCRAFT INSTRUMENTATION
Includes all avionics systems, cockpit and cabin display devices, and flight instruments intended for use in aircraft.
For related information see also 04 Aircraft Communications and Navigation; 08 Aircraft Stability and Control; 19 Spacecraft Instrumentation and Astrionics; and 35 Instrumentation and Photography.
20050204039 NASA Dryden Flight Research Center, Edwards, CA, USA
Active Aeroelastic Wing Aerodynamic Model Development and Validation for a Modified F/A-18A
Cumming, Stephen B.; Diebler, Corey G.; [2005]; 42 pp.; In English; AIAA Atmospheric Flight Mechanics Conference, 15-18 Aug. 2005, San Francisco, CA, USA; No Copyright; Avail: CASI; A03, Hardcopy
A new aerodynamic model has been developed and validated for a modified F/A-18A used for the Active Aeroelastic Wing (AAW) research program. The goal of the program was to demonstrate the advantages of using the inherent flexibility of an aircraft to enhance its performance. The research aircraft was an F/A-18A with wings modified to reduce stiffness and a new control system to increase control authority. There have been two flight phases. Data gathered from the first flight phase were used to create the new aerodynamic model.Amaximum-likelihood output-error parameter estimation technique was used to obtain stability and control derivatives. The derivatives were incorporated into the National Aeronautics and Space Administration F-18 simulation, validated, and used to develop new AAW control laws. The second phase of flights was used to evaluate the handling qualities of the AAW aircraft and the control law design process, and to further test the accuracy of the new model. The flight test envelope covered Mach numbers between 0.85 and 1.30 and dynamic pressures from 600 to 1250 pound-force per square foot. The results presented in this report demonstrate that a thorough parameter identification analysis can be used to improve upon models that were developed using other means. This report describes the parameter estimation technique used, details the validation techniques, discusses differences between previously existing F/A-18 models, and presents results from the second phase of research flights. Author
Aeroelasticity; F-18 Aircraft; Wings; NASA Programs; Aircraft Models
20050204113 NASA Dryden Flight Research Center, Edwards, CA, USA
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Loads Model Development and Analysis for the F/A-18 Active Aeroelastic Wing Airplane
Allen, Michael J.; Lizotte, Andrew M.; Dibley, Ryan P.; Clarke, Robert; [2005]; 14 pp.; In English; AIAA Guidance, Navigation and Control Conference, 15 Aug. 2005, San Francisco, CA, USA; No Copyright; Avail: CASI; A03, Hardcopy
The Active Aeroelastic Wing airplane was successfully flight-tested in March 2005. During phase 1 of the two-phase program, an onboard excitation system provided independent control surface movements that were used to develop a loads model for the wing structure and wing control surfaces. The resulting loads model, which was used to develop the control laws for phase 2, is described. The loads model was developed from flight data through the use of a multiple linear regression technique. The loads model input consisted of aircraft states and control surface positions, in addition to nonlinear inputs that were calculated from flight-measured parameters. The loads model output for each wing consisted of wing-root bending moment and torque, wing-fold bending moment and torque, inboard and outboard leading-edge flap hinge moment, trailing-edge flap hinge moment, and aileron hinge moment. The development of the Active Aeroelastic Wing loads model is described, and the ability of the model to predict loads during phase 2 research maneuvers is demonstrated. Results show a good match to phase 2 flight data for all loads except inboard and outboard leading-edge flap hinge moments at certain flight conditions. The average load prediction errors for all loads at all flight conditions are 9.1 percent for maximum stick-deflection rolls, 4.4 percent for 5-g windup turns, and 7.7 percent for 4-g rolling pullouts. Author
Aircraft Models; Loads (Forces); Wing Loading; F-18 Aircraft; Aeroelastic Research Wings
20050205806 NASA Dryden Flight Research Center, Edwards, CA, USA
Aeroelastic Flight Data Analysis with the Hilbert-Huang Algorithm
Brenner, Marty; Prazenica, Chad; [2005]; 29 pp.; In English; AIAA Atmospheric Flight Mechanics Conference, 15-18 Aug. 2005, San Francisco, CA, USA; Copyright; Avail: CASI; A03, Hardcopy
This paper investigates the utility of the Hilbert-Huang transform for the analysis of aeroelastic flight data. It is well known that the classical Hilbert transform can be used for time-frequency analysis of functions or signals. Unfortunately, the Hilbert transform can only be effectively applied to an extremely small class of signals, namely those that are characterized by a single frequency component at any instant in time. The recently-developed Hilbert-Huang algorithm addresses the limitations of the classical Hilbert transform through a process known as empirical mode decomposition. Using this approach, the data is filtered into a series of intrinsic mode functions, each of which admits a well-behaved Hilbert transform. In this manner, the Hilbert-Huang algorithm affords time-frequency analysis of a large class of signals. This powerful tool has been applied in the analysis of scientific data, structural system identification, mechanical system fault detection, and even image processing. The purpose of this paper is to demonstrate the potential applications of the Hilbert-Huang algorithm for the analysis of aeroelastic systems, with improvements such as localized/online processing. Applications for correlations between system input and output, and amongst output sensors, are discussed to characterize the time-varying amplitude and frequency correlations present in the various components of multiple data channels. Online stability analyses and modal identification are also presented. Examples are given using aeroelastic test data from the F/A-18 Active Aeroelastic Wing aircraft, an Aerostructures Test Wing, and pitch-plunge simulation. Author
Aeroelasticity; Hilbert Transformation; Algorithms; F-18 Aircraft; Aeroelastic Research Wings; Data Processing
20050205988 RAND Corp., Santa Monica, CA USA
Assessing the Impact of Future Operations on Trainer Aircraft Requirements
Ausink, John A.; Marken, Richard S.; Miller, Laura; Manacapilli, Thomas; Taylor,WilliamW.; Thirtle, Michael R.; Jan. 2005; 104 pp.; In English Contract(s)/Grant(s): F49642-01-C-0003
Report No.(s): AD-A436033; RAND/MG-348-AF; No Copyright; Avail: Defense Technical Information Center (DTIC) This monograph examines how the skills needed to perform future military missions might affect the capabilities required of new pilot training systems. In the next few years, the Air Force must decide to replace or extend the lives of two of its trainer aircraft. This monograph addresses which skills should be taught in undergraduate flying training, which are so different that they cannot be taught in current training aircraft, and what impact these issues have on decisions to replace or extend the lives of the aircraft. DTIC
Education; Flight Training; Pilots; Training Aircraft; Training Devices
20050206019 Texas Research Inst., Inc., Austin, TX USA
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Development of a CB Resistant Durable, Flexible Hydration System
Hall, Peyton W.; Zeller, Frank T.; Bulluck, John W.; Dingus, Michael L.; Jan. 2002; 8 pp.; In English Contract(s)/Grant(s): N68335-99-C-0119 Report No.(s): AD-A436077; No Copyright; Avail: Defense Technical Information Center (DTIC)
A durable, flexible hydration system resistant to contamination by contact with VX, GD, and HD chemical agents, as well as damage by the decontaminants sodium hypochlorite and DS-2 is being developed for aviator use. Decisions have been made regarding the often conflicting concerns of water potability and protection from chemical agents in compliant polymeric materials. Water potability and health concerns dictate the use of high purity thermoplastic resins with very limited use of lubricants, accelerators, antioxidants, and plasticizers. Flexible chemically resistant applications demand the use of highly crosslinked, permeation resistant, plasticized elastomers or thermosets. By using multilayer laminated and unlaminated polymer composites, as well as closely examining permeation properties, a balance has been reached to meet these conflicting requirements. DTIC
Cockpits; Contamination; Durability; Hydration; Water
20050206055 Air Force Inst. of Tech., Wright-Patterson AFB, OH USA
Comparing F-16 Maintenance Scheduling Philosophies
Iakovidis, Konstantinos; Jun. 2005; 401 pp.; In English; Original contains color illustrations Report No.(s): AD-A436130; AFIT/GLM/ENS/05-12; No Copyright; Avail: Defense Technical Information Center (DTIC)
In the F-16 fighter community it is believed that the flying schedule can make or break a wing’s maintenance effort. Nevertheless, there is no published scientific support behind many commonly used maintenance scheduling philosophies. The problem is that a generally accepted overall scheduling philosophy to improve the long term health of the fleet does not exist. The purpose of this research is tri-fold: to identify the most important scheduling philosophies, to identify the most meaningful metrics that capture the long term health of the fleet and maintenance effectiveness, and to compare the various philosophies using the performance measures to help maintenance managers choose the most appropriate one. A stochastic simulation model was generated to model the sortie generation process, and a full factorial Design of Experiment was used to identify statistically significant differences among the proposed scheduling philosophies. The results of the study show that the ‘3 waves Monday through Thursday and 1 wave on Friday’ maintenance scheduling philosophy seems to outperform the other philosophies regardless of the sortie surge level or the time between landing and take off. This philosophy is also less sensitive than the alternative philosophies in sortie level and time between landing and take-off changes. DTIC
F-16 Aircraft; Fighter Aircraft; Jet Aircraft; Maintenance; Scheduling
20050206061 Air Force Inst. of Tech., Wright-Patterson AFB, OH USA
Predicting the Cost per Flying Hour for the F-16 Using Programmatic and Operational Variables
Hawkins, Eric M.; Jun. 2005; 114 pp.; In English; Original contains color illustrations Report No.(s): AD-A436138; AFIT/GOR/ENC/05-01; No Copyright; Avail: CASI; A06, Hardcopy
This research analyzes operational and programmatic data from all Air National Guard and 13 of 14 active duty F-16C/D Fighter Wings (FW) from 1998 to 2004 in search of explanatory variables that influence a wing’s Cost Per Flying Hour (CPFH). Using data from both the Air Force Total Ownership Cost database and from the Air Force Knowledge Systems database, this research evaluates the predictive ability of the following nine explanatory variables: aircraft age, average sortie duration, MajCOM, base location, utilization rate, percent engine type, percent block, percent deployed, and previous year’s CPFH, the last four of which were previously untested. Additionally, this research builds regression models that accurately predict the CPFH of an F-16C/D FW using these operational and programmatic variables. This research concludes that the following variables are highly predictive and quantifies the relative influence of each of these variables: utilization rate, base location, percent block, percent engine type, average age of aircraft, and the previous year’s CPFH. Finally, this research identifies a lurking variable and proposes two possible explanations. DTIC
Armed Forces (United States); Costs; F-16 Aircraft; Fighter Aircraft; Predictions
20050206077 Massachusetts Inst. of Tech., Cambridge, MA USA
The Effects of Target Location Uncertainty in Game Theoretic Solutions to Optimal Trajectory Formulations
Morales, Daniel M.; Jun. 2005; 234 pp.; In English; Original contains color illustrations Report No.(s): AD-A436163; No Copyright; Avail: Defense Technical Information Center (DTIC)
The integration of a variety of Intelligence, Surveillance, and Reconnaissance (ISR) assets is vital to the acquisition of knowledge critical to battlefield success. Missions performed by a penetrating Unmanned Aerial Vehicle (UAV) are of particular interest. The environment in which UAVs must operate includes Surface-to-Air Missile (SAM) sites with extended ranges, among other threats. SAM location uncertainty, terrain obscuration, and radar/sensor capabilities all contribute to the complexity of the situation. This thesis provides a game theoretic approach to determine optimal UAV strategies against enemy SAM sites. It is shown that most characteristics of the UAV or SAM have negligible effects on both image quality (Iq) and probability of kill (Pk) (probability of the SAM shooting down the UAV). Instead, SAM location uncertainty has the largest influence. After only 0.5 miles of uncertainty, the Pk of a UAV assuming perfect knowledge of the SAM location rises to 0.56. When the uncertainty rises to about four miles, the Pk rises to 0.99. When the UAV takes uncertainty into account, the results are not much better. Assuming that the SAM may be at one of three possible locations, the result is an average Pk of 0.49 or 0.79, depending on which optimization routine was used. Extending this situation to five, seven, and nine possible SAM locations results in an increase in Pk to 0.99 at seven locations. An even more realistic scenario involving the UAV optimizing a path through a large area of varying probabilities results in an 85% chance of getting shot down if the SAM is located within a five-mile radius of the center of the area. Outside of this area, the UAV is guaranteed to get shot down with a Pk of 0.99. Other techniques and methods must be explored and used in combination with Radar Cross Section (RCS) management to ensure the continuing collection of valuable ISR imagery in the coming years. DTIC
Detection; Game Theory; Missile Trajectories; Position (Location); Target Acquisition; Targets; Trajectories
20050206116 Air Force Research Lab., Wright-Patterson AFB, OH USA
Manual Versus Speech Input for Unmanned Aerial Vehicle Control Station Operations
Draper, Mark; Calhoun, Gloria; Ruff, Heath; Williamson, David; Barry, Timothy; Oct. 2003; 6 pp.; In English Report No.(s): AD-A436248; No Copyright; Avail: Defense Technical Information Center (DTIC)
Unmanned aerial vehicle (UAV) control stations feature multiple menu pages with systems accessed by keyboard presses. Use of speech-based input may enable operators to navigate through menus and select options more quickly. This experiment examined the utility of conventional manual input versus speech input for tasks performed by operators of a UAV control station simulator at two levels of mission difficulty. Pilots performed a continuous flight/navigation control task while completing eight different data entry task types with each input modality. Results showed that speech input was significantly better than manual input in terms of task completion time, task accuracy, flight/navigation measures, and pilot ratings. Across tasks, data entry time was reduced by approximately 40% with speech input. Additional research is warranted to confirm that this head-up, hands-free control is still beneficial in operational UAV control station auditory environments and does not conflict with intercom operations and intra-crew communications. DTIC
Drone Vehicles; Manuals; Pilotless Aircraft; Speech Recognition
20050206128 Rapid Imaging Software, Inc., Albuquerque, NM USA
Synthetic Vision System for Improving Unmanned Aerial Vehicle Operator Situation Awareness
Calhoun, Gloria L.; Draper, Mark H.; Abernathy, Mike F.; Delgado, Frank; Patzek, Michael; May 2005; 13 pp.; In English; Original contains color illustrations Report No.(s): AD-A436272; No Copyright; Avail: Defense Technical Information Center (DTIC)
The Air Force Research Laboratory’s Human Effectiveness Directorate (AFRL/ HE) supports research addressing human factors associated with Unmanned Aerial Vehicle (UAV) operator control stations. Recent research, in collaboration with Rapid Imaging Software, Inc., has focused on determining the value of combining synthetic vision data with live camera video presented on a UAV control station display. Information is constructed from databases (e.g., terrain, cultural features, pre-mission plan, etc.), as well as numerous information updates via networked communication with other sources (e.g., weather, intel). This information is overlaid conformal, in real time, onto the dynamic camera video image display presented to operators. Synthetic vision overlay technology is expected to improve operator situation awareness by highlighting key spatial information elements of interest directly onto the video image, such as threat locations, expected locations of targets, landmarks, emergency airfields, etc. Also, it may help maintain an operator’s situation awareness during periods of video datalink degradation/dropout and when operating in conditions of poor visibility. Additionally, this technology may serve as an intuitive means of distributed communications between geographically separated users. This paper discusses the tailoring of synthetic overlay technology for several UAV applications. Pertinent human factors issues are detailed, as well as the usability, simulation, and flight test evaluations required to determine how best to combine synthetic visual data with live camera video presented on a ground control station display and validate that a synthetic vision system is beneficial for UAV applications. DTIC
Drone Vehicles; Enhanced Vision; Pilotless Aircraft; Surveillance; Visual Perception
20050206159 Defence Research and Development Canada, Valcartier, Quebec Canada
Low Cost Solution for Strategic Air Mobility Line-Tasking Problem Implemented in the Decision Scheduling System (DSS)
Boukhtouta, A.; Guitouni, A.; Berger, J.; Lo, N.; Dec. 2004; 26 pp.; In English Report No.(s): AD-A436341; DRDC-TN-2003-354; No Copyright; Avail: CASI; A03, Hardcopy
The Decision Scheduling System (DSS) has been developed by the GERAD team under a research and development program. The DSS’s aim is to solve the airline assignment problem designated as the Air mobility Line Tasking Problem (LTP). Moreover, to be able to solve the LTP problem, the DSS required the Gencol software commercialized by the AdOpt firm. But, the licence cost of the software make the deployment of the DSS too expensive. A study has been undertaken by RDDC Valcartier to evaluate on one hand the DSS and to present on the other hand alternative approaches that can be implemented in DSS to solve the Air mobility LTP. DTIC
Decision Making; Low Cost; Mobility; Scheduling; Software Development Tools
Source: NASA.
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