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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Friction and wear characteristics of wire-brush skids

The testing technique consisted of towing the skids with a ground test vehicle over asphalt and concrete surfaces at ground speeds up to 80 km/hr (50 mph) and bearing pressures up to 689 kPa (100 psi) over sliding distances up to 1585 m (5200 ft). Results indicate that the friction coefficient developed by wire brush skids is essentially independent of ground speed, is slightly increased with increasing bearing pressure, is noticeably affected by surface texture, and is not degraded by surface wetness. Skid wear is shown to increase with increasing bearing pressure and with increasing ground speed and is dependent on the nature of the surface. Runway surface damage caused by the skids was in the form of an abrasive scrubbing action rather than physical damage.

Dreher, R. C.↗
NASA NTRS2012

A Large-Scale Design Integration Approach Developed in Conjunction with the Ares Launch Vehicle Program

This paper presents a method for performing large-scale design integration, taking a classical 2D drawing envelope and interface approach and applying it to modern three dimensional computer aided design (3D CAD) systems. Today, the paradigm often used when performing design integration with 3D models involves a digital mockup of an overall vehicle, in the form of a massive, fully detailed, CAD assembly; therefore, adding unnecessary burden and overhead to design and product data management processes. While fully detailed data may yield a broad depth of design detail, pertinent integration features are often obscured under the excessive amounts of information, making them difficult to discern. In contrast, the envelope and interface method results in a reduction in both the amount and complexity of information necessary for design integration while yielding significant savings in time and effort when applied to today's complex design integration projects. This approach, combining classical and modern methods, proved advantageous during the complex design integration activities of the Ares I vehicle. Downstream processes, benefiting from this approach by reducing development and design cycle time, include: Creation of analysis models for the Aerodynamic discipline; Vehicle to ground interface development; Documentation development for the vehicle assembly.

Redmon, John W.↗
NASA NTRS2017

A Multi-Modality Mobility Concept for a Small Package Delivery UAV

This paper will discuss a different approach to the typical notional small package delivery drone concept. Most delivery drone concepts employ a point-to-point aerial delivery CONOPS (Concept of Operations) from a warehouse directly to the front or back yards of a customers residence or a commercial office space. Instead, the proposed approach is somewhat analogous to current postal deliveries: a small aerial vehicle flies from a warehouse to designated neighborhood VTOL (Vertical Take-Off and Landing) landing spots where the aerial vehicle then converts to a "roadable" (ground-mobility) vehicle that then transits on sidewalks and/or bicycle paths till it arrives to the residence/office drop-off points. This concept and associated platform or vehicle will be referred in this paper as MICHAEL (Multimodal Intra-City Hauling and Aerial-Effected Logistics) concept. It is suggested that the MICHAEL concept potentially results in a more community friendly "delivery drone" approach.

UAV↗
NASA NTRS2016

Aeroelastic Ground Wind Loads Analysis Tool for Launch Vehicles

Launch vehicles are exposed to ground winds during rollout and on the launch pad that can induce static and dynamic loads. Of particular concern are the dynamic loads caused by vortex shedding from nearly-cylindrical structures. When the frequency of vortex shedding nears that of a lowly-damped structural mode, the dynamic loads can be more than an order of magnitude greater than mean drag loads. Accurately predicting vehicle response to vortex shedding during the design and analysis cycles is difficult and typically exceeds the practical capabilities of modern computational fluid dynamics codes. Therefore, mitigating the ground wind loads risk typically requires wind-tunnel tests of dynamically-scaled models that are time consuming and expensive to conduct. In recent years, NASA has developed a ground wind loads analysis tool for launch vehicles to fill this analytical capability gap in order to provide predictions for prelaunch static and dynamic loads. This paper includes a background of the ground wind loads problem and the current state-of-the-art. It then discusses the history and significance of the analysis tool and the methodology used to develop it. Finally, results of the analysis tool are compared to wind-tunnel and full-scale data of various geometries and Reynolds numbers.

Ivanco, Thomas G.↗
NASA NTRSDate not supplied

Analysis of the Electrical Grid for UAM

A wide range of challenges must be overcome to conduct Urban Air Mobility (UAM) operations at scale with electric vertical takeoff and landing aircraft as envisioned. This presentation is on an analysis of one potential infrastructure challenge for UAM: available electrical grid power capacity. The success of UAM depends on the availability of electricity, which will be increasingly impacted by the proliferation of ground electric vehicles over time. Under the best-case assumption that electricity can be transmitted and distributed as needed within each interconnection (i.e., electrical grid), it is estimated that the maximum number of UAM aircraft that can charge simultaneously in the continental United States will decrease by 20% from about 595 thousand in the year 2021 to about 475 thousand in the year 2050 due to the projected increase in ground electric vehicles.

electrical grid; urban air mobility; electric vehi↗
DOE OSTI2026

Enhanced Electrocatalytic and Cathode‐Electrolyte Interfacial Properties With a Pr‐Based Simple Perovskite/Ruddlesden‐Popper Nanocomposite Cathode in Protonic Ceramic Fuel Cells

The sluggish kinetics and poor stability of the oxygen reduction reaction (ORR) remain the primary bottleneck for achieving high performance in protonic ceramic fuel cells (PCFCs) at intermediate temperatures (400–650°C). In this work, a Pr-based nanocomposite cathode comprised of simple perovskite phase (PrNi 0.7 Co 0.3 O 3-δ ) and Ruddlesden-Popper phase (Co-doped Pr 4 Ni 3 O 10+δ ) is developed. Although PrNi 0.7 Co 0.3 O 3-δ solely stands as a good cathode with facile proton transfer, combining the superior catalytic activity against oxygen on the Ruddlesden-Popper phase boosts the ORR performance further. The designed nanocomposite cathode outperforms the simple perovskite cathode, attributed to enhanced oxygen absorption and surface diffusion with the Ruddlesden-Popper phase. A precursor-based cathode deposition technique is also developed to achieve cathode grain sizes of ∼100 nm. A single cell with the nanocomposite cathode delivers a peak power density of 1.38 W cm −2 at 650°C, among the highest in reported PCFCs with Pr-based cathodes, with a small degradation rate of 0.145 mV h −1 during 250 h stability test. Further investigation of cathode-electrolyte interface revealed interfacial PrO 2 phase formation, promoted by abundant Pr 6 O 11 in the nanocomposite precursor powder, thereby improving both ohmic resistance and stability. These findings highlight the effectiveness of the nanocomposite cathode and underscore its advantages on interfacial properties.

08 - HYDROGEN↗
NASA NTRS1972

Study 2.5 final report. DORCA computer program. Volume 5: Analysis report

A modification of the Dynamic Operational Requirements and Cost Analysis Program to perform traffic analyses of the automated satellite program is described. Inherent in the analyses of the automated satellite program was the assumption that a number of vehicles were available to perform any or all of the missions within the satellite program. The objective of the modification was to select a vehicle or group of vehicles for performing all of the missions at the lowest possible cost. A vehicle selection routine and the capability to simulate ground based vehicle operational modes were incorporated into the program.

Campbell, N.↗
NASA NTRS1990

In-flight flow field analysis on the NASA F-18 high alpha research vehicle with comparisons to ground facility data

In-flight flow visualization results of the vortical flow on the forebody and leading-edge extensions (LEX) of an F-18 research aircraft have been presented for angles of attack from 15.8 to 42.5 deg and for sideslip angles up to 7.5 deg. Water tunnel results using a 3-percent scale F-18 model and a variety of wind tunnel results are used for comparison and interpretation of the flight results. The LEX vortex core breakdown point moved forward with increasing angle of attack. For a constant angle of attack, the windward LEX vortex core breakdown moves forward and inboard with sideslip and the leeward vortex core breakdown moves aft and outboard. For a constant angle of attack, the windward location of interaction moved aft with increasing sideslip and the leeward interaction moved forward.

Del Frate, John H.↗
NASA NTRS1972

An investigation of the landing characteristics of the NASA-MSC August 1969 baseline orbiter configuration in ground effect

A 0.05 scale model of the NASA-MSC August 1969 baseline shuttle craft was tested in Texas A&M University's 7- x 10-foot low speed wind tunnel facility. The purpose of the test was to determine the landing aerodynamic characteristics of the shuttle craft vehicle in ground effect and to evaluate control surface hinge moments experienced in the cruise and landing operational phases of flight. Analysis of the final data will allow evaluation of vehicle flight stability in ground effect and estimation of vehicle control surface power system requirements.

Chambliss, E. B.↗
NASA NTRS1966

Meeting on Ground Wind Load Problems in Relation to Launch Vehicles

An unclassified technical meeting on ground wind load problems in relation to launch vehicles was held at the Langley Research Center on June 7 and 8, 1966. The meeting covered several sessions having the following topics: Specific Vehicle Results; Definition of Atmospheric Inputs; Experimental and Analytical Simulation Techniques; Basic Studies of Cylindrical Bodies; and Where Do We Go From Here? - The Designer's Viewpoint. The purpose of the meeting was to provide a forum for direct exchange of information and ideas between government, industry, and university personnel who are actively engaged in this area of work. In addition to focusing attention on current research and development information, the meeting also attempted to offer useful guidance on existing programs and on planning future efforts. The size of the meeting was kept small in order to encourage informal across-the-conference-table discussions among the attendees. In order to promote timely distribution of the papers presented at the meeting, this document has been printed using copy provided by the authors without the customary NASA editing.

CIRCULAR CYLINDER↗