Tech Briefs

Evaluation of Aeronautical Design Standard – 33 Using a UH-60A Black Hawk

In 1982, the U.S. Army Aeroflightdynamics Directorate (AFDD), then assigned under the U.S. Army Aviation Systems Command (AVSCOM), began development of a new handling qualities specification for military rotorcraft. This effort resulted in the U.S. Army's initial Aeronautical Design Standard–33 (ADS-33A), “Handling Qualities Requirements for Military Rotorcraft,” published in May 1987. It was initially applied to the RAH-66 Comanche Helicopter program, meaning the handling qualities requirements generally related more to scout and attack classes of rotorcraft. As more data became available and lessons learned emerged from using ADS-33A, refinements were implemented into ADS-33B and ADS-33C).

Posted in: Briefs, Aerospace, Data Acquisition, Instrumentation, Test & Measurement, Transportation
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Circuit Models for Robust, Adaptive Neural Control

This project seeks to reproduce the neural circuits used by the nematode Caenorhabditis elegans for locomotion. Caenorhabditis elegans is a small (~1.2 millimeter) nematode found in rotting fruit in many parts of the world. It feeds on bacteria and is neither parasitic nor pathogenic. Although capable of sexual reproduction, most laboratory strains reproduce primarily as self-fertilizing hermaphrodites, with each adult hermaphrodite producing approximately 300 progeny (Figure 1).

Posted in: Briefs, Aerospace, Physical Sciences, Instrumentation, Test & Measurement
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Pulsed Microwave Plasma Instrumentation for Investigation of Plasma-Tuned Multiphase Combustion

Strategies to control solid rocket propellant regression rate require a robust throttling technique applicable to high performance propellant formulations. Currently, several methods to control and throttle either motors or subscale propellant strands exist, including chamber pressure control (e.g. pintle nozzles or rapid depressurization quench), infrared laser irradiation of the burning surface to increase burning rates, development of inherently unstable combustion chamber geometries (producing either local pressure or velocity perturbations), and electrically sensitive hydroxylammonium nitrate (HAN)-based formulations in which burning rate is controlled by a voltage potential. However, these techniques are limited in that they either can only be used with low flame temperature (low specific impulse) propellants, result in low propulsion system mass fraction (pintle), are only capable of producing a single perturbation, or are formulation specific.

Posted in: Briefs, Aerospace, RF & Microwave Electronics
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Synthetic Aperture Radar for Helicopter Landing in Degraded Visual Environments

The development of sensors to assist helicopter landing in degraded visual environments (DVEs) is currently an important US Army requirement addressing the Survivability of Future Vertical Lift Platforms program, one of the Army's modernization priorities.

Posted in: Briefs, Aerospace, Data Acquisition, Detectors, Sensors
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Novel Characterization Methods for Anisotropic and Mixed-Conduction Materials

State-of-the-art electronic and optoelectronic devices require electronic materials with specialized properties that cannot be characterized with standard methods, or that must be characterized with extra precision. As a result of this research, the following new materials characterization methods have been developed:

Posted in: Briefs, Aerospace
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Microstructural and Mechanical Characterization of 2-D and 3-D SiC/SiNC Ceramic-Matrix Composites

The purpose of this endeavor was to investigate the effect of 3-D weave architecture on PIP-processed ceramic-matrix composites (CMC). Microstructural studies were performed to document the resulting microstructure and mechanical testing was performed to determine the high-temperature durability of the five different variants of SiC/SiNC CMC investigated.

Posted in: Briefs, Aerospace
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Evaluation of Peel Ply Surface Preparation of Composite Surfaces for Secondary Bonding

Lightweight composite structures offer significant long-term cost-saving opportunities for the U.S. Army as replacements for traditional metal structures. However, high-strength economical bonding processes must be developed to join composites in order for them to be viable replacements. The Army is exploring approaches, also under evaluation in the commercial aerospace industry, to reduce the process steps associated with composite bonding.

Posted in: Briefs, Aerospace
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