Micro Air Vehicles Serve as Eyes in the Sky for Ground Troops

Honeywell Aerospace has developed the Micro Air Vehicle (MAV), an unmanned aerial vehicle (UAV) based on ducted-fan technology that recently was deployed in Iraq to identify improvised explosive devices (IEDs) from the sky. The deployment marked the first time a ducted-fan UAV was used during combat missions. The MAV, and subsequent generations of the vehicle already in use, could change the face of military reconnaissance, as well as help civilian law enforcement and aviation officials.

Posted in: Articles, Aerospace, Surveillance, Fans, Military aircraft, Military vehicles and equipment, Unmanned aerial vehicles

Network Keeps Line of Communication Open to Convoys

An airman riding as part of a convoy escort team in Iraq keys his radio microphone to check in with his base, and hears nothing but dead air. The U.S. Air Force is leading a joint implementation of a Radio over Internet Protocol Routed Network (RIPRnet) communication system that prevents such a scenario. RIPRnet ties convoy radios in with Internet-based technology to extend their range, providing robust, clear, reliable, and secure communications for soldiers, sailors, airmen, and Marines who are out on the roads of Iraq.

Posted in: Articles, Aerospace

Protection Schemes for Advanced Shipboard Electrical Systems

A research program has made progress toward the development of schemes for protection against faults in next-generation DC zonal shipboard electrical systems (DC SESs) and for configuration management in these systems to enable surviving parts of the systems to continue to distribute electric power to critical loads. Computational simulations of a representative prototype DC SES have shown that these schemes could afford protection at a system level (in contradistinction to a local level), thereby imparting, to the DC SES, an intended capability for self-healing.

Posted in: Briefs, Electronics & Computers, Architecture, Electrical systems, Reliability, Marine vehicles and equipment

DC Power Converter for 200°C Containing SiC Transistors

A DC-to-DC power converter, nominally rated for a power of 180 W, an input potential of 28 V, an output potential of 270 V, and a maximum operating temperature of 200°C has been designed, built, and tested. This power converter serves as a prototype for further development of power converters required to be capable of operating in high-temperature environments in diverse settings, including automobile, aircraft, and spacecraft engines, and oil and gas wells.

Posted in: Briefs, Electronics & Computers, Capacitors, Transistors, Product development

Simulation of a Flywheel Energy-Storage System

A computational model has been developed to simulate the operation of a laboratory flywheel energy-storage system that is a subsystem of the Flywheel Attitude Control, Energy Transmission, and Storage (FACETS) system located at Kirtland Air Force Base in New Mexico. The FACETS, which includes three advanced flywheel energy-storage units and an apparatus denoted the Agile Multi- Purpose Satellite Simulator (AMPSS), is used to demonstrate conceptual spacecraft operations involving integral combinations of attitude-control maneuvers and energy-storage operations. The flywheel units include high-hoop-strength carbon composite rotors that turn on magnetic bearings. The flywheels have a maximum rated angular speed of 40,000 rpm, making it possible to store as much a 1 kW·hr of energy in each unit. An air bearing supports the entire AMPSS test article allowing three-axis rotation with minimal damping. In addition to the flywheel units, the system includes DC-to-DC power converters and a three-phase rectifier.

Posted in: Briefs, Information Technology, Computer simulation, Energy storage systems, Flywheels, Spacecraft

A Comparison of SiC-Based Devices for Use as Power Switches

A report details a survey of the state of technological development and commercial availability of SiC-based electronic devices that has been performed to evaluate the suitability of such devices as power switches in present and future applications in which high reliability and/or capability for high-temperature operation are or will be required. Examples of such applications include high-temperature motor drives, switch modules, and DC-to- DC power converters, and DC-to-AC power inverters. The survey consisted primarily of a comparative study of the relative advantages and disadvantages of SiCbased vertical-junction field-effect transistors (VJFETs) and SiC-based metal oxide/semiconductor field-effect transistors (MOSFETs). Other devices, including conventional Si-based MOSFETs and SiCbased bipolar junction transistors (BJTs) were considered, but only in passing, because it was assumed, at the beginning of the study, that the superiority of SiCbased VJFETs and SiC-based MOSFETs over other devices for power-switching applications had already been established.

Posted in: Briefs, Electronics & Computers, Switches, Transistors, Technical reference

Advances in Organic-Based Electronic Devices

A program of research has addressed multiple topics in the field of electronic and optoelectronic devices based on polymers and other organic substances, with special attention to memory devices and solar photovoltaic cells. The accomplishments of this research are summarized as follows:

Posted in: Briefs, Electronics & Computers, Electronic equipment, Research and development, Polymers

AlxInyGa1-x-yN Ultraviolet Light-Emitting Triodes

Light-emitting triodes (LETs) have been the focus of a program of research with a goal of increasing the quantum efficiencies of ultraviolet-lightemitting devices implemented in the AlxInyGa1-x-yN (0 ≤ x+y ≤ 1) material system. Heretofore, AlxInyGa1-x-yN-based light-emitting diodes (LEDs) have exhibited "efficiency droop" — decreasing quantum efficiency with increasing injection current. LETs can be used as means of studying and overcoming efficiency droop.

Posted in: Briefs, Electronics & Computers, Light emitting diodes (LEDs), Performance upgrades

Less-Polluting Resins for Molding Composite Structures

Liquid resins that are suitable for use in molding composite- material structural panels and that contain and emit smaller amounts of air-polluting volatile organic compounds than do corresponding commercial resins have been invented. In particular, these resins are under study as less-polluting potential substitutes for commercial vinyl ester and unsaturated polyester resins heretofore used in making lightweight composite panels for some military vehicles.

Posted in: Briefs, Materials, Volatile organic compounds, Product development, Composite materials, Lightweight materials, Resins, Military vehicles and equipment

Some Advances in High-Temperature Superconductor Coatings

Several advances were made in a program focused on the science and technology of high-temperature superconductors [especially yttrium barium copper oxide ("YBCO")] deposited on normal electrical conductors. This program was part of a continuing effort to develop superconductor-coated normal conductors for use in electric-power systems of interest to the Air Force.

Posted in: Briefs, Materials, Electrical systems, Coatings Colorants and Finishes, Conductivity, Heat resistant materials, Military aircraft, Military vehicles and equipment