News Article | February 15, 2017
The Army’s PEO Aviation Utility Helicopters Project Office; the Aviation and Missile Command; and the Aviation and Missile Research, Development and Engineering Center (AMRDEC) teamed with principal industry partner Redstone Defense Systems (RDS) to develop the UH-60V aircraft. RDS, a joint venture between Yulista Aviation, Inc. and Science and Engineering Services, is currently modifying the first 3 UH-60V aircraft and hosted a First Flight ceremony for Engineering Development Model (EDM) 1. RDS updated the existing UH-60L analog architecture to a digital infrastructure enabling the aircraft to have a similar Pilot-Vehicle Interface (PVI) and interoperability to the UH-60M. RDS provided bussed avionics and block upgrade functionality that meets critical international flight requirements as well as enhanced aircrew mission situational awareness, decreased pilot workload and increased mission safety. The First Flight Ceremony was held at the Yulista M4 Hangar in Meridianville, AL on January 19, 2017. The First Flight Ceremony date was set two years prior and is a major milestone for the program. Within the next couple of weeks, the aircraft will go through final maintenance actions and acceptance test procedures prior to being handed off to the Aviation Flight Test Directorate (AFTD). The UH-60V Program is just one of the many innovative and enhanced solutions serving the warfighter performed by RDS and Yulista. RDS is the prime contractor for the AMRDEC Prototype Integration Facility (PIF), system integrator for the UH-60V. Yulista Aviation is an Alaskan Native Owned Small Business headquartered in Huntsville, AL. For more information about RDS and Yulista, visit http://www.yulistaaviation.com.
News Article | November 7, 2016
A new, green process developed by a University of Alabama in Huntsville (UAH) professor for producing the carbon fiber that forms ablative rocket nozzles and heat shields has been awarded a patent. The new process could be of interest to NASA, which has a dwindling stockpile of cellulose rayon fiber that dates back to the late 1990s. That's when manufacturing ceased because the old process used acids and caustics that generated hazardous materials as byproducts. "This is a green process, so it is environmentally clean," says Dr. William Kaukler, an associate research professor at UAH's Rotorcraft Systems Engineering and Simulation Center and a NASA contractor for 35 years. "We recycle all the byproducts." Dr. Kaukler developed the new ionic process with funding from the U.S. Army's Aviation and Missile Research, Development and Engineering Center (AMRDEC). "Other people know about using ionic processes to make fibers but they are not making carbon fibers with them," Dr. Kaukler says. "The trick was to make the properties of this fiber match the properties of the North American Rayon Corp. (NARC) fiber." NARC ceased rayon production in the U.S. after it was unable financially to comply with Environmental Protection Agency regulations for the hazardous wastes created. To form a solid fuel rocket nozzle, layers of carbon fiber fabric made from carbonized rayon are coated with pitch and wound around a mandrel, and then heat-treated to convert the pitch to solid carbon. The resulting nozzle will be a carbon fiber reinforced-carbon composite. A single large solid rocket motor like that used for shuttle boosters can use up to 35 tons of fiber. The rocket nozzles of Army missiles are made from phenolic resin and this same carbon fiber. "This carbon fiber is not the same fiber that you'd go out and make aircraft or car parts from," says Dr. Kaukler. "This is the only way to make the carbon fiber that is suitable for rocket nozzles, is to start with cellulosic fiber." The more common carbon fiber used in structural applications is made from polyacrylonitrile (PAN) and, while stronger, its thermal conductivity is too high. Heat created from the rocket's burning fuel slowly burns away the interior of the nozzle in flight. "That's why you have to make the fiber out of cellulose, because it has the lowest rate of thermal conductivity of any fiber," Dr. Kaukler says. The low conductivity keeps the propellant's heat in for more propulsion efficiency and it prevents the nozzle from burning away too quickly in flight, with disastrous consequences. Scaling up the process to manufacturing dimensions could aid NASA as it moves forward with solid rocket motors in its next-generation Space Launch System, and it could prove useful for heat shields used in re-entry to Earth's atmosphere or on planetary probes designed for landing, Dr. Kaukler says. "It would be useful for any aero-entry onto a planet."
News Article | November 22, 2016
A new, green process developed by a University of Alabama in Huntsville (UAH) professor for producing the carbon fiber that forms ablative rocket nozzles and heat shields has been awarded a patent. ‘This is a green process, so it is environmentally clean,’ said Dr William Kaukler, an associate research professor at UAH’s Rotorcraft Systems Engineering and Simulation Center and a NASA contractor for 35 years. ‘We recycle all the byproducts.’ Dr Kaukler developed the new ionic process at UAH’s Reliability and Failure Analysis Laboratory with funding from the U.S. Army’s Aviation and Missile Research, Development and Engineering Center (AMRDEC). ‘Other people know about using ionic processes to make fibers but they are not making carbon fibers with them,’ Dr Kaukler said. To form a solid fuel rocket nozzle, layers of carbon fiber fabric made from carbonized rayon are coated with pitch and wound around a mandrel, and then heat-treated to convert the pitch to solid carbon. The resulting nozzle will be a carbon fiber reinforced-carbon composite. A single large solid rocket motor like that used for shuttle boosters can use up to 35 tons of fiber. The rocket nozzles of Army missiles are made from phenolic resin and this same carbon fiber. ‘This carbon fiber is not the same fiber that you’d go out and make aircraft or car parts from,’ said Dr Kaukler. ‘This is the only way to make the carbon fiber that is suitable for rocket nozzles, is to start with cellulosic fiber.’ The more common carbon fiber used in structural applications is made from polyacrylonitrile (PAN) and, while stronger, its thermal conductivity is too high. ‘That’s why you have to make the fiber out of cellulose, because it has the lowest rate of thermal conductivity of any fiber,’ Dr Kaukler suggested. The low conductivity keeps the propellant’s heat in for more propulsion efficiency and it prevents the nozzle from burning away too quickly in flight, with disastrous consequences. ‘Scaling up the process to manufacturing dimensions could aid NASA as it moves forward with solid rocket motors in its next-generation Space Launch System, and it could prove useful for heat shields used in re-entry to Earth’s atmosphere or on planetary probes designed for landing, he added. This story is reprinted from material from the University of Alabama in Huntsville, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.
Zubair A.,Rice University |
Tsentalovich D.E.,Rice University |
Young C.C.,Rice University |
Heimbeck M.S.,Aviation and Missile Research |
And 4 more authors.
Applied Physics Letters | Year: 2016
Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼-30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2-1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs. © 2016 AIP Publishing LLC.
News Article | July 7, 2015
A team of researchers from the U.S. Army Aviation and Missile Research, Development and Engineering Center at the Redstone Arsenal in Alabama have developed a new photovoltaic solar cell. It converts light energy into electric energy, and is both smaller and cheaper than the options that are currently available. Since current solar panels use silicon construction, they tend not to utilize the maximum power from the sun. That's because silicon's band gap – the wavelength of light that is absorbed and converted into electricity – is extremely narrow compared to the sun's spectrum beaming down. This means the panels are also susceptible to wear, heat damage and stress caused by the ultraviolet and infrared light shining down. This new "breakthrough" solar panel created by the Army has silver and gold between the semiconductor layers for a thickness of a few hundred nanometers that allows direct control of energy absorption for energy conversion — making the solar cells work more efficiently. This cutting-edge design has resulted in smaller photovoltaic solar cells that are 1,000 times thinner. They are also more cost effective, and due to the cell's geometry, the sunlight absorption rate is not affected by the angle between the sun and the cell. Because the solar panels can absorb and convert the same amount of energy no matter the angle, there is no need for expensive sun-tracking stands. "Low-cost, compact, flexible and efficient solar cells are destined to impact all sorts of Department of Defense applications, as lightweight solar panels will eventually power all kinds of equipment, particularly in remote, inaccessible areas," said Dr. Michael Scalora, solar cell co-creator and research physicist at the U.S. Army AMRDEC. "The key to the development of efficient, compact solar cells are advances in nanotechnology, nano-fabrication techniques and thin-film production." The Army has received a patent for their new solar cells, but the technology is still in its early stages with plans for future research. Be sure to follow Tech Times on Twitter and visit our Facebook page.
News Article | November 9, 2015
The U.S. military is where many new technologies get their start. So much of what we now see as standard tech was once being invented in a military lab. Continuing that tradition, a team of Army scientists has created a new solar cell that could mark a major breakthrough. The researchers have patented a new type of solar cell that is less expensive to manufacture, stronger and more robust than current solar cell technology. The main difference between this solar cell and those in existing solar panels is their size -- the new solar cell is approximately 1,000 times thinner. The thin-film cell consists of layers of silver and gold between the semiconductor layers, but the combined thickness is still only a few hundred nanometers thick, compared to a piece of paper which is 100,000 nanometers thick. The cell also overcomes some of the major problems with current solar tech like wear out or damage from high heat that comes from the absorption of great amounts of ultraviolet and infrared radiation that can't actually be turned into electricity due to a narrow band gap (the wavelength of light that can effectively be used to generate electricity). The addition of the silver and gold layers widens that bandgap meaning that the new solar cells can absorb and convert more of that UV and infrared radiation into electricity, which not only makes the technology more efficient, but also makes it much stronger and resilient. The solar cells can also be tuned to reflect the excess radiation if needed. The Army says that the geometry of the solar cells allows them to absorb the same rate of sunlight at any angle, which means that they don't need sophisticated sun tracking systems to generate the maximum amount of energy. "Low-cost, compact, flexible and efficient solar cells are destined to impact all sorts of Department of Defense applications, as lightweight solar panels will eventually power all kinds of equipment, particularly in remote, inaccessible areas," said Dr. Michael Scalora, a research physicist at the U.S. Army Aviation and Missile Research, Development and Engineering Center. The technology is just in the beginning stages, but the researchers see applications far beyond the military when it's ready.
Yeo H.,NASA |
Yeo H.,U.S. Army |
Yeo H.,Aviation and Missile Research |
Journal of Aircraft | Year: 2015
Maximum rotor lift capability is investigated using wind-tunnel test data of McHugh (modified 1/10-scale CH-47B rotor) and a full-scale UH-60A rotor. Rotor performance calculations with the comprehensive rotorcraft analysis CAMRAD II are compared with the wind-tunnel test data. The analysis of the McHugh rotor with the Reynolds-number-corrected airfoil table shows good correlation with the measurements for μ = 0.1 to 0.5 and is able to predict the maximum rotor lift reasonably well, especially at 0.2 ≤ μ ≤ 0.4. The analysis is also able to predict the maximum lift of the full-scale UH-60A rotor within about 3.5% at μ = 0 .24 and 0.3. Calculations with dynamic stall models, in general, show only a small influence on the rotor performance and are not necessary to predict maximum lift. Airfoils have an important role in defining the maximum lift capability of the rotor. The VR-12 airfoil, which has stall characteristics superior to the baseline V23010 airfoil, substantially improves the maximum lift capability of the McHugh rotor, showing the potential to improve the behavior of a rotor by improving the airfoil's static stall characteristics.
Berry J.L.,Aviation and Missile Research |
Hayduke D.,Materials Sciences Corporation
International SAMPE Symposium and Exhibition (Proceedings) | Year: 2010
Progressive failure analysis of carbon epoxy pressure vessels is an important tool for optimum weight and durability designs. This paper compares failure criteria implemented within a progressive failure modeling method for fiber composite materials within the ABAQUS environment. The model assessed was the fiber damage and failure model written by Materials Science Corporation (MSC) with the capability of modeling composite failure based on Max-Stress, Max-Strain, and Hashin criterion. Evaluation of these models was based on implicit, static, reduced integration, single shell element results compared to published experimental results of ultimate laminate tensile stress for multiple lay-ups and off-axis loading angles. All the criteria yielded comparable results to the experimental study. Average percent differences of 25.47, 9.22, and 8.00 were found for the Hashin, Max-Strain, and Max-Stress models, respectively.
Hansson J.,U.S. Software Engineering Institute |
Wrage L.,U.S. Software Engineering Institute |
Feiler P.H.,U.S. Software Engineering Institute |
Morley J.,U.S. Software Engineering Institute |
And 2 more authors.
IEEE Security and Privacy | Year: 2010
The modeling of system quality attributes, including security, is often done with low-fidelity software models and disjointed architectural specifications by various engineers using their own specialized notations. These models typically aren't maintained or documented throughout the life cycle and make it difficult to obtain a system view. However, a single-source architecture model annotated with analysis-specific information lets designers reflect changes in the various analysis models with little effort. This approach also lets designers conduct adequate trade-off analyses and evaluate architectural variations prior to system realization. This article describes how model-based development using the Architecture Analysis and Design Language (AADL) and compatible analysis tools provides the platform for multidimensional, multifidelity analysis and verification. © 2010 IEEE.
Stephenson J.H.,Aviation and Missile Research |
Annual Forum Proceedings - AHS International | Year: 2015
Blade-vortex interaction noise measurements are analyzed for an AS350B helicopter operated at 7000 ft elevation above sea level. Blade-vortex interaction (BVI) noise from four, 6 degree descent conditions are investigated with descents flown at 80 knot true and indicated airspeed, as well as 4400 and 391S pound take-off weights. BVI noise is extracted from the acquired acoustic signals by way of a previously developed time-frequency analysis technique. The BVI extraction technique is shown to provide a better localization of BVI noise, compared to the standard Fourier transform integration method. Using this technique, it was discovered that large changes in BVI noise amplitude occurred due to changes in vehicle gross weight. Changes in BVI noise amplitude were too large to be due solely to changes in the vortex strength caused by varying vehicle weight. Instead, it is suggested that vehicle weight modifies the tip-path-plane angle of attack, as well as induced inflow, resulting in large variations of BVI noise. It was also shown that defining flight conditions by true airspeed, rather than indicated airspeed, provides more consistent BVI noise signals.