Criteria

Text:
Display:

Results

Viewing 1 to 30 of 849
2017-12-08
Paper
SN-0003
Small tactical UAVs (SUAVs) have made their mark in military operations with their ability to gather and provide localized, real-time information. Typical uses include perimeter surveillance of remote military compounds, over-the-horizon surveillance, and remote monitoring of critical logistics routes. However, their potential to take on increased and increasingly complex missions is hampered by their limited endurance. This work explores research done under the auspices of the European Commission’s Fuel Cell and Hydrogen Joint Undertaking on a fuel cell and battery hybrid energy storage system that could increase the total amount of onboard energy storage, while continuing to deliver the peak power needs of the SUAV.
2017-09-19
Technical Paper
2017-01-2020
Michael Croegaert
Abstract Modern military aircraft platforms are using more and more power which results in an ever increasing power density (SWaP). This in turn, generates more heat that has to be dissipated from the instrument panel and cockpit of the aircraft. Complicating this further is that the use of structural composites which are not efficient conductors of heat and the mission requirements of small heat signatures. Therefore alternative means of extracting the heat from the avionics systems must be used. Liquid cooled systems have the advantage over air cooled systems of a much higher heat transfer rate and the fact that the heat can be transported a significant distance from the source. Liquid cooled avionics have their own challenges as well.
2016-09-20
Journal Article
2016-01-1988
Rodney Yeu, Jason Wells, Chad Miller, Jane Thompson
Abstract Movement toward more-electric architectures in military and commercial airborne systems has led to electrical power systems (EPSs) with complex power flow dynamics and advanced technologies specifically designed to improve power quality in the system. As such, there is a need for tools that can quickly analyze the impact of technology insertion on the system-level dynamic transient and spectral power quality and assess tradeoffs between impact on power quality versus weight and volume. Traditionally, this type of system level analysis is performed through computationally intensive time-domain simulations involving high fidelity models or left until the hardware fabrication and integration stage. In order to provide a more rapid analysis prior to hardware development and integration, stochastic equivalent circuit analysis is developed that can provide power quality assessment directly in the frequency domain.
2016-09-20
Technical Paper
2016-01-2056
Nikolaus Thorell, Vaibhav Kumar, Narayanan Komerath
Abstract Combat aircraft maneuvering at high angles of attack or in landing approach are likely to encounter conditions where the flow over the swept wings is yawed. This paper examines the effect of yaw on the spectra of turbulence above and aft of the wing, in the region where fins and control surfaces are located. Prior work has shown the occurrence of narrowband velocity fluctuations in this region for most combat aircraft models, including those with twin fins. Fin vibration and damage has been traced to excitation by such narrowband fluctuations. The narrowband fluctuations themselves have been traced to the wing surface. The issue in this paper is the effect of yaw on these fluctuations, as well as on the aerodynamic loads on a wing, without including the perturbations due to the airframe.
2016-09-20
Technical Paper
2016-01-2000
Mark Bodie, Thierry Pamphile, Jon Zumberge, Thomas Baudendistel, Michael Boyd
Abstract As technology for both military and civilian aviation systems mature into a new era, techniques to test and evaluate these systems have become of great interest. To achieve a general understanding as well as save time and cost, the use of computer modeling and simulation for component, subsystem or integrated system testing has become a central part of technology development programs. However, the evolving complexity of the systems being modeled leads to a tremendous increase in the complexity of the developed models. To gain confidence in these models there is a need to evaluate the risk in using those models for decision making. Statistical model validation techniques are used to assess the risk of using a given model in decision making exercises. In this paper, we formulate a transient model validation challenge problem for an air cycle machine (ACM) and present a hardware test bench used to generate experimental data relevant to the model.
2016-09-20
Journal Article
2016-01-2030
Jon Zumberge, Michael Boyd, Raul Ordonez
Cost and performance requirements are driving military and commercial systems to become highly integrated, optimized systems which require more sophisticated, highly complex controls. To realize benefits of those complex controls and make confident decisions, the validation of both plant and control models becomes critical. To quickly develop controls for these systems, it is beneficial to develop plant models and determine the uncertainty of those models to predict performance and stability of the control algorithms. A process of model and control algorithm validation for a dc-dc boost converter circuit based on acceptance sampling is presented here. The validation process described in this paper is based on MIL-STD 3022 with emphasis on requirements settings and the testing process. The key contribution of this paper is the process for model and control algorithm validation, specifically a method for decomposing the problem into model and control algorithm validation stages.
2016-09-20
Technical Paper
2016-01-2019
Richard P. Johnston
Abstract An advanced composite Blended Wing Body (BWB) air frame previously used as a study aircraft to transport a 75-ton military cargo halfway around the world and back unrefueled has been modified and evaluated as a 150-ton heavy lifter. The modifications include enlarging the forward trim canard, reducing fuel load by 151,850 lbs, increasing the high-mach NASA-type counter-rotating propellers from 12 feet to 13 feet diameter, extending the propeller support pylons' height by 6 inches and modifying cruise flight and prop control strategies. Due to structural and propulsion system changes, the air frame Operational Empty Weight (OEW) was increased by 1,850 lbs. but the maximum Take Off Gross Weight (TOGW) was held to 800,000 lbs. Brief descriptions of the major propulsion system components are provided. In addition, a comparison of three different counter-rotating propeller systems is presented. The first is a Standard configuration.
2016-04-05
Technical Paper
2016-01-0742
Michael Szedlmayer, Chol-Bum M. Kweon
Abstract The objective of the study is to characterize combustion and performance of a multi-cylinder turbocharged direct-injection (DI) diesel engine at altitude conditions according to the International Standard Atmosphere (ISA). Experiments were performed on the 6.6-liter turbocharged DI diesel engine, a model similar to that of the Army’s Joint Light Tactical Vehicle. The engine was installed in the US Army Research Laboratory Small Engine Altitude Research Facility. Outside air temperature (OAT) and outside air pressure were independently controlled to match the ISA-OAT at selected altitude conditions: sea level, 1524, 3048, and 4572 m. The test engine is equipped with a single-stage variable nozzle turbocharger and Bosch CRIN 3 common-rail injection system. Three load conditions (i.e., low, mid, and high) were selected at 1400 rpm to investigate combustion and performance of the engine using Jet Propellant-8 (JP-8) fuel.
2015-09-15
Journal Article
2015-01-2581
Scott Eberhardt
Abstract World War 1 began with the airplane as a frail, unarmed means of observing enemy troop movements and ended with the airplane as a powerful, much more evolved weapon of war. There were specialized roles for fighter, bomber and ground attack aircraft as well as newly developed aerial strategies and tactics for operational effectiveness. Many aircraft design technologies greatly matured during the war. Four will be the subject of this paper: Drag reduction, aircraft handling qualities, stability and control, airfoil design technology, and structures design technology. Propulsion and armament also matured greatly but are not discussed in the paper. The discussion of drag reduction will illustrate the innovations of the British on external wire bracing drag, the French on cowl design and the Germans on cantilevered wings and induced drag.
2015-09-15
Technical Paper
2015-01-2570
Brandon Liberi, Praditukrit Kijjakarn, Narayanan Komerath
Abstract Loads slung under aircraft can go into divergent oscillations coupling multiple degrees of freedom. Predicting the highest safe flight speed for a vehicle-load combination is a critical challenge, both for military missions over hostile areas, and for evacuation/rescue operations. The primary difficulty was that of obtaining well-resolved airload maps covering the arbitrary attitudes that a slung load may take. High speed rotorcraft using tilting rotors and co-axial rotors can fly at speeds that imply high dynamic pressure, making aerodynamic loads significant even on very dense loads such as armored vehicles, artillery weapons, and ammunition. The Continuous Rotation method demonstrated in our prior work enables routine prediction of divergence speeds. We build on prior work to explore the prediction of divergence speed for practical configurations such as military vehicles, which often have complex bluff body shapes.
2015-09-15
Technical Paper
2015-01-2552
Helmut Plankl
Abstract The paper will start with a short introduction to the structure of the Airbus Group, before addressing the Airbus Defence and Space business line Military Aircraft. The Rig Operation department for airborne solutions within this organisation is responsible for the development, design, operation and support of ground test facilities and test support systems, which are used for design validation and verification of civil and military air systems. The main part of this document will start with a typical sequence of tests in our Test Centre. The presentation will then focus on some advanced methods used during the qualification of test equipment and to improve the efficiency of ground test facilities in terms of cost, time and risk reduction. The next topic is tool-based rig management and control, beginning with test preparation and test shift planning and also covering aspects of configuration control, automatisation of test facilities and support of the test report.
2014-09-16
Technical Paper
2014-01-2208
Michael Baldwin
Abstract This paper will illustrate how the increasing electrical power demands of military and aerospace applications can continue to successfully be met by high performance electromechanical relays. To meet these higher demands engineering compatibility must be properly understood between the intended application demands and relay switching performance parameters. With high performance electromechanical relays continuing to play a critical part in military and aerospace applications it is more important than ever that engineers capture all of the electrical power switching requirements. A critical area within powering military and aerospace systems is relay life when capacitive load switching. Capacitive loads generate high current levels that are transient in duration and often adversely affect the relay lifespan at the component level and the military or aerospace application reliability at the systems level.
2014-09-16
Technical Paper
2014-01-2209
Marco Amrhein, Brian Raczkowski, Jason Wells, Eric Walters, Sean Field, Jason Gousy
Abstract Analyzing and maintaining power quality in an electrical power system (EPS) is essential to ensure that power generation, distribution, and loads function as expected within their designated operating regimes. Standards such as MIL-STD-704 and associated documents provide the framework for power quality metrics that need to be satisfied under varying operating conditions. However, analyzing these power quality metrics within a fully integrated EPS based solely on measurements of relevant signals is a different challenge that requires a separate framework containing rules for data acquisition, metric calculations, and applicability of metrics in certain operating conditions/modes. Many EPS employed throughout industry and government feature various alternating-current (ac) power systems.
2014-09-16
Technical Paper
2014-01-2174
Nicholas Ernest, Kelly Cohen, Corey Schumacher, David Casbeer
Abstract Looking forward to an autonomous Unmanned Combat Aerial Vehicle (UCAV) for future applications, it becomes apparent that on-board intelligent controllers will be necessary for these advanced systems. LETHA (Learning Enhanced Tactical Handling Algorithm) was created to develop intelligent managers for these advanced unmanned craft through the novel means of a genetic cascading fuzzy system. In this approach, a genetic algorithm creates rule bases and optimizes membership functions for multiple fuzzy logic systems, whose inputs and outputs feed into one another alongside crisp data. A simulation space referred to as HADES (Hoplological Autonomous Defend and Engage Simulation) was created in which LETHA can train the UCAVs intelligent controllers.
2014-09-16
Technical Paper
2014-01-2168
Khadeeja Nusrath, Ankur Sarmah, Jatinder Singh
This paper presents the implementation of flight path reconstruction (FPR) and wind estimation techniques applied to a high performance fighter aircraft. The analysis is carried out for the flight test data gathered and stored in a Crash Data Recorder (CDR). The data signals obtained from CDR are generally highly noisy, with frequent data drop outs and also with low sampling rate. The estimation technique applied for data reconstruction is the extended Kalman filtering (EKF). The reconstructed trajectories can be compared with the actual flight trajectories such that, in case of unavailability of data from other sources (e.g., digital flight control computer), the algorithm should be able to reconstruct the trajectories with the minimum set of data available from the CDR. Wind estimation along with the trajectory reconstruction can give better accuracy in airspeed as well as flow angles.
2014-09-16
Technical Paper
2014-01-2192
Philip Abolmoali, Javier A. Parrilla, Awatef Hamed
Abstract The optimal integration of vehicle subsystems is of critical importance in the design of future energy efficient fighter aircraft. The INVENT (INtegrated Vehicle ENergy Technology) program has been dedicated to this endeavor through modeling/simulation of thermal management, power generation & distribution, & actuation subsystems. Achieving dual cooling & power generation capability from a single subsystem would be consistent with current efforts in system integration optimization. In this paper, we present a reconfiguration of an archetypal closed-loop air cycle system for a modern fighter as an open-loop gas generator cycle operating interchangeably between refrigeration and auxiliary power modes. A numerical model was developed within NPSS to assess maximum power extraction capabilities of a system originally designed for cooling purposes under different operating conditions.
2014-04-01
Technical Paper
2014-01-0488
Peter Kempf
Abstract Discuss the basics of posturing and positioning of the full range of occupants necessary to cover the required anthropometric demographics in combat vehicles, both ground and air, since there are similarities to both and that they are both very different than the traditional automotive packaging scenarios. It is based on the Eye Reference Point and the Design Eye Point. Discuss the three Reach Zones: Primary, Secondary and Tertiary. Discuss Vision Zones and potentially ground intercepts. Discuss body clearances, both static and dynamic. Discuss the basic effects of packaging occupants with body armor with respect to SRP's and MSRP's.
2013-09-17
Journal Article
2013-01-2089
F. Javier Fernandez-Garcia, Javier Valdeolmos
Air to Air refueling (AAR) operations are typically performed with dedicated tanker A/C. Most existing tankers are derived from civil airliners like the A330MRTT from Airbus Military or from military transport A/C with permanent modifications for the tanker role. For being able to refuel in flight some type of receivers like medium and light turboprops, helicopters and certain UAVs, the tanker aircraft should be able to fly at low speeds. For that role medium/small size turboprop military transport aircraft, like the C295 from Airbus Military are ideally suited. This paper proposes a new palletized AAR kit for conversion of a transport A/C into a tanker. The kit includes all the needed air refueling systems, and can be installed on an existing military transport aircraft with rear cargo door ramp without big permanent modifications to the base platform.
2012-10-22
Journal Article
2012-01-2145
Giovanni Tomasi
Lighting and illumination systems using visible Lasers light sources are being developed under a number of US Navy programs to reduce the ship's costs including acquisition, installation, operation, and maintenance. Recent advances resulting from research initiatives funded thru the Office of Naval Research Mantech program and a Navy SBIR project are making broader applications of this technology feasible, including possible transition into aircrafts for position, landing, anti-collision, cargo loading, wing icing detection, and interior lights. The development of these lasers is being driven by the high definition projection industry, with substantial investments made to bring the technology to broad scale implementation, and with the anticipated increase in product availability and decrease in costs. The laser systems offer significant advantages over fiber optic systems using other light sources including metal halide and LEDs.
2012-10-22
Technical Paper
2012-01-2192
F.Javier Fernandez-Garcia, Javier Valdeolmos
Today's civil airliners integrate electrical power capability properly sized to supply the growing demands of modern aircraft systems, that are more electrical than ever. The conversion of civil aircraft into a military derivative aircraft faces the challenge of rearranging the available generation capability to feed the new power-hungry military systems while at the same time minimizing the impact on certification of the base aircraft for use on civil operations. This challenge is particularly difficult when the new military systems demand high peak power consumption, as in the case of the conversion of a civil airliner into a military Multi-Role Transport Tanker aircraft with high performance multipoint refueling capabilities. In fact the selection of the type of actuation (either electrical or hydraulic) for the refueling systems is heavily conditioned by the excess of either electrical or hydraulic power available in the base aircraft.
2012-10-22
Journal Article
2012-01-2181
Evgeni Ganev, William Warr, Arif Salam
This paper introduces a novel method for an electric power generation system (EPGS) employing a lead-unity-lag (LUL) permanent-magnet (PM) generator operation for a direct current (DC) power distribution bus. In addition, background information of the prior art for a leading power factor EPGS is discussed. The concept of the new approach is defined and a comparative analysis between the new and old state-of-the-art solutions are documented. The performance features and technical details of the system parameters with respect to power generation system requirements are presented and discussed. Analysis and testing results are included. Finally, the advantages of this system, a conclusion, and recommendations for future work are provided. Test results from a system having elements of this novel approach are included. With this method for an LUL EPGS, the capability of the high-performance electric power generation systems is improved substantially.
2012-10-22
Journal Article
2012-01-2179
Steven C. Griggs, Steven Mark Iden, Peter T. Lamm
Efforts are underway to develop technologies to create a more Energy Optimized Aircraft (EOA). The question becomes how should one define an Energy Optimized Aircraft and how should energy optimization be measured to determine what is optimal? This paper provides a top level point of view for the goal of an Energy Optimized Aircraft. It outlines how one should approach the design of such an aircraft, the relevant vehicle systems technologies to enable energy optimization for fighter aircraft, and potential aircraft level measurands for determining degrees of goodness associated with incorporating different technologies. The top-to-bottom approach is provided for traceability of technologies being developed to aircraft and mission level goals.
2012-10-22
Technical Paper
2012-01-2184
Michael Baldwin
This paper will illustrate how the increasing electrical demands to power military and aerospace applications can successfully be met by high performance electromechanical relays. To meet these higher demands engineering compatibility must be properly understood between the intended application and relay switching performance parameters. With high performance electromechanical relays continuing to play a critical part in military and aerospace applications it is more important than ever before that engineers capture all of the military and aerospace electrical power requirements. A critical area within powering military and aerospace systems is capacitive load switching. Capacitive loads can generate high current levels that are transient in duration and adversely affect the relay at the component level and the military or aerospace applications at the higher systems levels. As capacitance increases the amplitude and duration of the current transient also increase.
2012-10-22
Journal Article
2012-01-2182
Charles Singer, Corinne M. Guernsey, Jason Gousy, John DeWitte Cottingham III, John Frerichs
Aircraft utilize electrical power for many functions ranging from simple devices such as resistive heaters to highly advanced and complex systems responsible for communications, situational awareness, electronic warfare and fly-by-wire flight controls. The operational states of these electronic systems affect safety, mission success and the overall economic expense of operation and maintenance. These electronic systems rely on electrical power within established limits of power quality. In recent years, electrical power quality is becoming excessively degraded due to increased usage of nonlinear and dynamic loads coupled to aircraft power systems that were neither designed nor tested for these loads. Legacy power generation systems were designed for electrical loads with resistive and inductive properties, which previously represented the majority of actual aircraft electrical loads.
2012-10-22
Technical Paper
2012-01-2173
Kevin McCarthy, Alex Heltzel, Eric Walters, Richard Deitrich, Justin Coffey, Sam Septembre, Michael McGonigle
Advanced tactical aircraft and their propulsion systems produce an order of magnitude more heat than legacy designs and offer fewer viable heat rejection opportunities. The current approach uses aircraft fuel as a primary heat sink which is either cooled by ram air and returned to the aircraft, or rejected off the aircraft when burned by the engine. Traditionally, aircraft have been limited in mission capability by the design performance and the available fuel quantity; however, potential thermal limitations have presented a new mission challenge. Joker and bingo range notifications based on fuel quantity remaining are common on modern fighters to ensure the pilot has the foresight to complete a mission segment and return to base before running out of fuel. Now, pilots may need to consider the possibility of a similar thermal joker/bingo concept until alternative LO heat rejection methods are discovered that remove limitations.
2012-10-22
Journal Article
2012-01-2122
Jim Springer, Terry Thomas, Douglas Gregory, Steve Low, Jaye Bass
Under AMRDEC's Aviation Multi-Platform Munition Program (AMPM) Science and Technology Program, a “Shadow Hawk” munition (developed by Lockheed Martin Missiles and Fire Control) was commanded and released using AMRDEC's Universal Test Pod (UTP) and successfully impacted the designated ground target. The UTP program pioneered usage of OSD Unmanned Aircraft System (UAS) Control Segment (UCS) Architecture Mission Effects Sub-domain and standardized STANAG 4586 weapon control messages that formed the basis of OSD's Data Link IP (draft). The UTP employed the Universal Armaments Interface (UAI) implemented in the UTP stores management system, which provides a developmental universal, open-architecture weapon interface. This was the first demonstration of a precision-guided weapon released from a RQ-7B Shadow UAS.
2012-10-22
Journal Article
2012-01-2242
Brian Vetter
The two primary wire construction types being used in military aircraft today are cross-linked Ethylene Tetrafluoroethylene (XL-ETFE) and composite fluoropolymer / polyimide tape wrap with an outer Polytetrafluoroethylene (PTFE) tape wrap. These insulations offer significant improvements over earlier polyimide (MIL-DTL-81381) and polyvinyl chloride (PVC) constructions but are not without drawbacks. XL-ETFE provides a low smoke, high fluid resistant, non-arc tracking insulation that is durable during installation and ground repair operations. However, durability and abrasion resistance are reduced at elevated temperatures, and maximum operating temperature peaks at 200 degrees Celsius. Composite insulation provides a more abrasion resistant solution with the inclusion of polyimide tape for hard surface chafe conditions and a PTFE outer layer that improves wear life during wire to wire contact.
2012-10-22
Journal Article
2012-01-2241
Oliviu Muja, David Lamper
Automated Fault Isolation of Intermittent Wiring/Conductive Path Systems Inside Weapons Replaceable Assemblies Wiring/conductive path faults inside Weapon Replaceable Assemblies (WRAs) that result in No Fault Found (NFF) or intermittent diagnosis are estimated to cost the DoD over $2B annually. To date there is no logistically supportable, standardized capability to reduce this annual cost. This report covers the development of this capability and its subsequent testing and fielding as a means to reduce this component repair costs. This new capability is called the Automated Wiring Test Set (AWTS) intermittent testing capability. To test the new capability, the F/A-18 APG-73 Radar Receiver (RR) chassis was selected due to its high repair cost and its #1 ranking as an avionics mission degrader for this type aircraft.
2012-10-22
Technical Paper
2012-01-2230
Yeong-Ren Lin, Yang Hu, Lei Zhou, David Woodburn, Thomas Wu, Louis C. Chow, Quinn Leland
In the aviation community, there is a high priority to develop all-electric aircraft. Electro-mechanical actuation systems would replace traditional, large, heavy and difficult-to-maintain hydraulic actuation systems. This movement from hydraulic actuation to electrical actuation enhances the flexibility to integrate redundancy and emergency system in future military aircraft. Elimination of the hydraulic fluid removes the possibility of leakage of corrosive hydraulic fluid and the associated fire hazard, as well as environmental concerns. The switch from hydraulic to electrical actuation provides additional benefits in reduced aircraft weight, improved survivability and improved maintainability. The heat load in an electro-mechanical actuation (EMA) is highly transient and localized in nature; therefore a phase change material could be embedded in the heat generating components to store peak heat load.
2011-10-18
Journal Article
2011-01-2750
Athanasios Lois, Nikolaos Bertos, Athanasios Ziliaskopoylos
The process of checking inspection points on combat aircraft after a mission, is critical for their operational readiness. Manufacturers include specific inspection procedures in their maintenance handbooks. These procedures consist of detailed instructions for each check, the minimum time required to complete each check as well as a suggested sequence. However, it has been observed, that technical crews can complete inspection in less time than suggested by the manual, without violation of the time prescribed for each inspection point. In this work we will try to apply routing algorithms, to improve the total inspection time, by finding the optimal inspection sequence. This will be achieved without violating any constraint set by the manufacturer, except for the small reduction of the service time on some points. The algorithms we will use is the algorithmic set usually applied for the well-known PDPTW (pickup and delivery problem with time windows).
Viewing 1 to 30 of 849

Filter