Tech Briefs

Pair-wise Trajectory Management (PTM) Airborne Human Machine Interface (HMI) Display Design

Langley Research Center, Hampton, Virginia Pair-wise Trajectory Management (PTM) is a concept that utilizes airborne and ground-based capabilities to enable airborne spacing operations in oceanic regions. The goal of PTM is to use enhanced surveillance, along with airborne tools, to manage the spacing between aircraft. Due to the precision of Automatic Dependent Surveillance- Broadcast (ADS-B) information, the PTM minimum spacing distance will be less than distances currently required of an air traffic controller. Reduced minimum distance will increase the capacity of aircraft operations at a given altitude or volume of airspace, thereby increasing time on desired trajectory and overall flight efficiency.

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Elastomeric Structural Attachment Concepts for Aircraft Flap Noise Reduction

A deformable structural element bridges the gap between the wing and the flap side edges, reducing noise. Langley Research Center, Hampton, Virginia Airframe noise is a significant part of the overall noise of typical transport aircraft during the approach and landing phases of flight. Airframe noise reduction is currently emphasized under the Environmentally Responsible Aviation (ERA) and Fixed Wing (FW) goals of NASA. A promising concept for trailing-edge-flap noise reduction is a flexible structural element or link that bridges the gap between the wing and the deployable flap side edges. The proposed solution is distinguished by minimization of the span-wise extent of the structural link, thereby minimizing the aerodynamic load on the link structure at the expense of increased deformation requirement. Development of such a flexible structural link necessitated application of hyperelastic materials, atypical structural configurations, and novel interface hardware. The resulting highly deformable structural concept was termed the FLEXible Side Edge Link (FLEXSEL) concept. Prediction of atypical elastomeric deformation responses from detailed structural analysis was essential for evaluating concepts that met legacy design constraints.

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Aircraft Engine Exhaust Nozzle System for Jet Noise Reduction

Langley Research Center, Hampton, Virginia Conventional aircraft typically include propulsion engines that are under the wing or tail surfaces. Each propulsion engine system includes an engine housed in a nacelle with an inlet and a nozzle system. Primary component noise sources from the engine system include the noise associated with the fan, compressor, turbine, and combustor, and the noise associated with the high-velocity jet exhaust flow. There are many methods for reducing the various noise sources from the aircraft, including those noise sources from the engine system. One method includes the use of the aircraft itself as an acoustic shield for the noise sources associated with the engines. This approach requires a new configuration of aircraft with the engines installed on the upper surface of the wing or fuselage, or an aircraft that has a hybrid wing and fuselage. Of the engine noise sources, the jet exhaust is a particular challenge due to the fact that the noise sources are in the exhaust flow itself, and therefore originate throughout the jet exhaust flow as many as ten engine diameters downstream of the nozzle system exit plane. Therefore, it is desirable to have an improved aircraft nozzle system that is capable of much more noise reduction when installed on the upper surface of the aircraft.

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Rotorcraft Noise Model (RNM)

A suite of computer models is used to evaluate noise generation by different aircraft to help meet the stricter noise standards of recent governmental regulations. Langley Research Center, Hampton, Virginia The Rotorcraft Noise Model (RNM) is a suite of computer models that predicts far-field noise for single or multiple flight vehicle operations. RNM calculates the effects of sound propagation over varying ground terrain for acoustic sources using geometrical theory of diffraction algorithms, and through a horizontally stratified atmosphere over uniform terrain with winds. RNM calculates the noise levels in the time domain and with a variety of integrated metrics at receiver positions on or above the ground at specific points of interest and over a uniform grid.

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Wheel Helmet to Reduce Landing Gear Noise

This innovation can be extended to a variety of aircraft types. Langley Research Center, Hampton, Virginia Airframe noise, produced by unsteady flow around aircraft structures, is an important source of aircraft noise during approach and landing. Sound radiating from the undercarriage is a major contributor to airframe noise. This type of noise is broadband in nature, caused by the complex unsteady flow field associated with the multitude of bluff bodies of various sizes and shapes that collectively make up a landing gear. Previous noise reduction concepts rely on flow alteration and shielding of the more critical gear subcomponents such as the main post, torque links, etc. Such concepts include fairings made of flexible and rigid materials, porous fairings, and wire mesh screens.

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Relativistic Ion Tracks (RITRACKS)

Lyndon B. Johnson Space Center, Houston, Texas Once astronauts venture beyond Earth’s protective atmosphere, they are exposed to the high-energy charged particles of galactic cosmic rays (GCR) and solar particle events (SPE), and secondary protons and neutrons. GCR are composed of ions, the great majority of which are protons (≈87%) and helium nuclei (≈12%). The heavy ions of atomic number greater than 2 comprise only a small fraction of the charged particles in the GCR, but they contribute significantly to the radiation dose and dose equivalent over time. Because of their ionization patterns in biomolecules, cells and tissues are distinct from terrestrial radiation, the resulting biological effects are poorly understood, and the health risks of these radiations are subject to large uncertainties.

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Medical Oxygen Concentrator for Microgravity Operation

Only ambient air and DC energy are required to operate the system. John H. Glenn Research Center, Cleveland, Ohio Supplemental oxygen delivery systems are vital to provide a critical life support respiratory function. Whether they are used for patients suffering from lung diseases or other illnesses, or astronauts donning an oxygen mask during a toxic spill or fire on a spacecraft, lightweight and portable oxygen delivery systems are in high demand. A lightweight portable oxygen concentrator was developed that can produce 1 to 6 lpm of pulse oxygen in a noiseless system that can be worn on the user’s hip or in a shoulder sling.

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