Aerodynamic Technologies to Enable Future Ultra-Efficient Subsonic Transports
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transonic truss-braced wing↗
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Development of selected advanced aerodynamics and active control concepts for commercial transport aircraft
Work done under the Energy Efficient Transport project in the field of advanced aerodynamics and active controls is summarized. The project task selections focused on the following: the investigation of long-duct nacelle shape variation on interference drag; the investigation of the adequacy of a simple control law for the elastic modes of a wing; the development of the aerodynamic technology at cruise and low speed of high-aspect-ratio supercritical wings of high performance; and the development of winglets for a second-generation jet transport. All the tasks involved analysis and substantial wind tunnel testing. The winglet program also included flight evaluation. It is considered that the technology base has been built for the application of high-aspect-ratio supercritical wings and for the use of winglets on second-generation transports.
Taylor, A. B.↗
First-Order Altitude Effects on the Cruise Efficiency of Subsonic Transport Aircraft
Aircraft fuel efficiency is a function of many different parameters, including characteristics of the engines, characteristics of the airframe, and the conditions under which the aircraft is operated. For a given vehicle, the airframe and engine characteristics are for the most part fixed quantities and efficiency is primarily a function of operational conditions. One important influence on cruise efficiency is cruise altitude. Various future scenarios have been postulated for cruise altitude, from the freedom to fly at optimum altitudes to altitude restrictions imposed for environmental reasons. This report provides background on the fundamental relationships determining aircraft cruise efficiency and examines the sensitivity of efficiency to cruise altitude. Analytical models of two current aircraft designs are used to derive quantitative results. Efficiency penalties are found to be generally less than 1% when within roughly 2000 ft of the optimum cruise altitude. Even the restrictive scenario of constant altitude cruise is found to result in a modest fuel consumption penalty if the fixed altitude is in an appropriate range.
Guynn, Mark D.↗
Airframes and aerodynamics
The first part of the paper discusses the Energy Efficient Transport program of the Aircraft Energy Efficiency (ACEE) program, giving attention to the development of active aerodynamics and active controls. The second part of the paper deals with two other portions of the ACEE program: Composite Primary Structures and Laminar Flow Control.
Leonard, R. W.↗
Transportation technology program: Strategic plan
The purpose of this report is to define the technology program required to meet the transportation technology needs for current and future civil space missions. It is a part of an integrated plan, prepared by NASA in part in response to the Augustine Committee recommendations, to describe and advocate expanded and more aggressive efforts in the development of advanced space technologies. This expanded program will provide a technology basis for future space missions to which the U.S. aspires, and will help to regain technology leadership for the U.S. on a broader front. The six aspects of this integrated program/plan deal with focused technologies to support space sciences, exploration, transportation, platforms, and operations as well as provide a Research and Technology Base Program. This volume describes the technologies needed to support transportation systems, e.g., technologies needed for upgrades to current transportation systems and to provide reliable and efficient transportation for future space missions. The Office of Aeronautics, Exploration, and Technology (OAET) solicited technology needs from the major agency technology users and the aerospace industry community and formed a transportation technology team (appendix A) to develop a technology program to respond to those needs related to transportation technologies. This report addresses the results of that team activity. It is a strategic plan intended for use as a planning document rather than as a project management tool. It is anticipated that this document will be primarily utilized by research & technology (R&T) management at the various NASA Centers as well as by officials at NASA Headquarters and by industry in planning their corporate Independent Research and Development (IR&D) investments.
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Transportation of volatile elements in thermally evolving planetesimals: An important role of metallic iron
Ordinary chondrites are considered to have experienced thermal metamorphism in small bodies. We are interested in behaviors of volatile elements in such a kind of thermally evolving planetesimals. Volatile elements generally have high vapor pressures at high temperature. In porous bodies, with a high gas permeability, volatile elements are transported efficiently over a long range. Behavior of volatile elements transported by permeable gas flow can be handled by an equation whose form is similar to that of the equation of thermal diffusion. We can follow transportation of heats and volatile elements in planetesimals, when parameters in these equations, initial conditions and chemical behavior of volatile elements are given. Recently, we discovered that nitrogen in equilibrated H-chondrites is mainly trapped in taenite (f.c.c. Fe-Ni), probably dissolved in interstitial sites. Fegley suggests that metallic iron cannot trap nitrogen in the solar nebula gas due to its very low nitrogen partial pressure. Approximately 1 bar of nitrogen pressure is required to explain the nitrogen content in taenite. We may expect high nitrogen gas partial pressure (possibly produced by vaporization of nitrogen-bearing solids such as organic materials) at the interior of thermally evolving planetesimals. Kinetic behavior of nitrogen in taenite suggests that it can easily be equilibrated with the ambient nitrogen gas at temperatures of approximately 500 C or higher. We consider that nitrogen is trapped in taenite through a nitrogen redistribution process occurred during the thermal metamorphic event.
Hashizume, K.↗
Nanoscale wicking methods and devices
A fluid transport method and fluid transport device are disclosed. Nanoscale fibers disposed in a patterned configuration allow transport of a fluid in absence of an external power source. The device may include two or more fluid transport components having different fluid transport efficiencies. The components may be separated by additional fluid transport components, to control fluid flow.
Zhou, Jijie↗
Impacts of Intercontinental Transport of Anthropogenic Fine Particulate Matter on Human Mortality
Fine particulate matter with diameter of 2.5 microns or less (PM2.5) is associated with premature mortality and can travel long distances, impacting air quality and health on intercontinental scales. We estimate the mortality impacts of 20 % anthropogenic primary PM2.5 and PM2.5 precursor emission reductions in each of four major industrial regions (North America, Europe, East Asia, and South Asia) using an ensemble of global chemical transport model simulations coordinated by the Task Force on Hemispheric Transport of Air Pollution and epidemiologically-derived concentration-response functions. We estimate that while 93-97 % of avoided deaths from reducing emissions in all four regions occur within the source region, 3-7 % (11,500; 95 % confidence interval, 8,800-14,200) occur outside the source region from concentrations transported between continents. Approximately 17 and 13 % of global deaths avoided by reducing North America and Europe emissions occur extraregionally, owing to large downwind populations, compared with 4 and 2 % for South and East Asia. The coarse resolution global models used here may underestimate intraregional health benefits occurring on local scales, affecting these relative contributions of extraregional versus intraregional health benefits. Compared with a previous study of 20 % ozone precursor emission reductions, we find that despite greater transport efficiency for ozone, absolute mortality impacts of intercontinental PM2.5 transport are comparable or greater for neighboring source-receptor pairs, due to the stronger effect of PM2.5 on mortality. However, uncertainties in modeling and concentration-response relationships are large for both estimates.
human health↗
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review
This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.
Source record↗
Pressure distribution data from tests of 2.29-meter (7.5-ft.) span EET high-lift research model in Langley 4- by 7-meter tunnel
A 2.29 m (7.5 ft.) span high-lift research model equipped with full-span leading-edge slat and part-span double-slotted trailing-edge flap was tested in the Langley 4- by 7-Meter Tunnel to determine the low speed performance characteristics of a representative high aspect ratio suprcritical wing. These tests were performed in support of the Energy Efficient Transport (EET) program which is one element of the Aircraft Energy Efficiency (ACEE) project. Static longitudinal forces and moments and chordwise pressure distributions at three spanwise stations were measured for cruise, climb, two take-off flap, and two landing flap wing configurations. The tabulated and plotted pressure distribution data is presented without analysis or discussion.
Morgan, H. L., Jr.↗
The Origin and Early Evolution of Membrane Proteins
The origin and early evolution of membrane proteins, and in particular ion channels, are considered from the point of view that the transmembrane segments of membrane proteins are structurally quite simple and do not require specific sequences to fold. We argue that the transport of solute species, especially ions, required an early evolution of efficient transport mechanisms, and that the emergence of simple ion channels was protobiologically plausible. We also argue that, despite their simple structure, such channels could possess properties that, at the first sight, appear to require markedly larger complexity. These properties can be subtly modulated by local modifications to the sequence rather than global changes in molecular architecture. In order to address the evolution and development of ion channels, we focus on identifying those protein domains that are commonly associated with ion channel proteins and are conserved throughout the three main domains of life (Eukarya, Prokarya, and Archaea). We discuss the potassium-sodium-calcium superfamily of voltage-gated ion channels, mechanosensitive channels, porins, and ABC-transporters and argue that these families of membrane channels have sufficiently universal architectures that they can readily adapt to the diverse functional demands arising during evolution.
Pohorille, Andrew↗
Aileron effectiveness for a subsonic transport model with a high-aspect-ratio supercritical wing
Aileron effectiveness for a subsonc energy efficient transport (EET) model with a high aspect ratio supercritical wing was determined in the 8-foot transonic pressure tunnel. Data are presented for ailerons located at three positions along the wing span. The ailerons were designed as a preliminary active control concept with gust load alleviation, maneuver load alleviation, and flutter suppression systems. A linear variation of rolling moment coefficient with angle of attack for individual and multiple aileron deflections at Mach numbers up to 0.81 is indicated. For Mach numbers greater than 0.81, the rolling moment coefficient data become nonlinear with increasing angle of attack. At Mach numbers near the design value increased aileron effectiveness resulted from aft transition locations, which produced relatively thin boundary layers and greater effective aileron deflections. Individual aileron deflections on the right wing panel produced only small effects on yawing moment and side force coefficients.
Jacobs, P. F.↗
Wind transport near the poles of Mars: Timescales of changes in deposition and erosion
Movement of sediment into and out of polar deposits is closely linked to the polar volatile budget and to changes in wind systems over the course of astronomically induced climate cycles. The present observations of the morphology of polar layered deposits, mantling sediments, dune fields, and variable surface features are the basis of inferences on the efficacy of polar sediment transport mechanisms. The time scales of formation of these features vary from days to perhaps 10(exp 6) yr, and latitudinal banding of dune fields near the poles may have been formed on timescales of 10(exp 7) yr. Orientations of intracrater dunes, dune crests, and wind streaks have been measured for latitudes -45 to -90 to compare features of likely different timescales of formation with models of wind flow from the south polar region. There is a complex variation with latitude of the indicated wind directions and of the efficacy of the resultant winds in orienting dune fields that suggests influence of frost cover on the ability of winds to move sediment in the spring and fall. Because of changes in the relative effectiveness of spring and fall winds expected with progression of the season of perihelion, the latitudinal variation in transport efficiency may mean that sediments at different latitudes dominantly respond to wind erosion and transport at different times during the perihelion cycle.
Thomas, Peter C.↗
Subsonic-Transport Core/Combustor Noise
The presentation is an overview of the propulsion-noise contributions from sources associated with the combustor for subsonic-transport aircraft. Sections of the talk cover: the impact of future compact high-efficiency core design trends on airport-community noise, the physical source mechanisms responsible for direct and indirect combustor noise, and combustor-noise prediction and measurement. The noise issues discussed are important to future gas-turbine propulsors, to envisioned hybrid-electric aircraft propulsion systems, and represent key challenges in the strategy to develop novel propulsion systems for ultra-efficient transport aircraft. The Advanced Air Transport Technology Project supports this effort.
Aeroacoustics, Combustor Noise, Turbomachinery Noi↗
Concept of Operations for Urban Air Mobility Command and Control Communications
Urban Air Mobility (UAM) is a burgeoning flight services concept for passenger and cargo airborne applications operating within and around urban environments. Among the services envisioned, most attention is being directed at airborne personal transport to improve transit time and mitigate automobile congestion. In addition, delivery services for more efficient transport of goods and local area information gathering for timely media dissemination and emergency monitoring will also likely be early UAM system applications. Among the infrastructure components in need of development are communications systems that manage these air vehicles. Not only will there be a need to communicate with the pilots in command of the aircraft for traffic management, but the control of the aircraft and monitoring of the aircraft systems will also need to use these communications systems to ensure safe operations.
Urban Air Mobility (UAM)↗
Vision-Based Distributed Sensing at Vertiports for Advanced Air Mobility and Urban Air Mobility Approach and Landing
Advanced Air Mobility (AAM) encompasses a broad vision for air transportation, including Urban Air Mobility (UAM) as a subset. AAM aims to create a more connected and efficient transportation network across various geographical settings. However, navigating AAM aircraft in GPS-denied or degraded environments during approach and landing is challenging. Traditional vision aids like glideslopes and localizers are limited in vertiport environments due to narrow beam constraints and reduced landing angle options. This paper addresses the need for accurate navigation solutions at vertiports by proposing a vision-based distributed sensing (VIDIS) system utilizing cameras with bundle adjustment to assist incoming AAM aircraft during approach and landing while monitoring surface movements to enhance safety and efficiency. Key focus areas for current and future vertiport developers include identifying suitable sensor types and infrastructure standards to support AAM operations and including vertiport markings as vision-based navigation aids. The proposed system offers a novel approach to overcoming navigation challenges in AAM operations, particularly in urban settings where traditional aids may be insufficient. Preliminary simulation results with distributed cameras demonstrate promising outcomes for implementing bundle adjustment techniques to enhance vision-based navigation solutions at vertiports. Generating waypoint-based trajectories via waypoint integration using explicit guidance synthesis (WINGS) creates smooth AAM trajectories for landing at vertiports by using the current waypoint's terminal conditions as the initial conditions for the next waypoint. Combining bundle adjustment's ground-based solution of vertiport features with WINGS, Coplanar Pose from Orthography and Scaling with Iterations (COPOSIT), and an extended Kalman filter (EKF) estimates the state of an incoming aircraft during approach and landing at vertiports. Future work includes testing VIDIS in a high-fidelity simulation and with real-world data.
Distributed sensing↗
Vision-Based Distributed Sensing at Vertiports for Advanced Air Mobility and Urban Air Mobility Approach and Landing
Advanced Air Mobility (AAM) encompasses a broad vision for air transportation, including Urban Air Mobility (UAM) as a subset. AAM aims to create a more connected and efficient transportation network across various geographical settings. However, navigating AAM aircraft in GPS-denied or degraded environments during approach and landing is challenging. Traditional vision aids like glideslopes and localizers are limited in vertiport environments due to narrow beam constraints and reduced landing angle options. This paper addresses the need for accurate navigation solutions at vertiports by proposing a vision-based distributed sensing (VIDIS) system utilizing cameras with bundle adjustment to assist incoming AAM aircraft during approach and landing while monitoring surface movements to enhance safety and efficiency. Key focus areas for current and future vertiport developers include identifying suitable sensor types and infrastructure standards to support AAM operations and including vertiport markings as vision-based navigation aids. The proposed system offers a novel approach to overcoming navigation challenges in AAM operations, particularly in urban settings where traditional aids may be insufficient. Preliminary simulation results with distributed cameras demonstrate promising outcomes for implementing bundle adjustment techniques to enhance vision-based navigation solutions at vertiports. Generating waypoint-based trajectories via waypoint integration using explicit guidance synthesis (WINGS) creates smooth AAM trajectories for landing at vertiports by using the current waypoint's terminal conditions as the initial conditions for the next waypoint. Combining bundle adjustment's ground-based solution of vertiport features with WINGS, Coplanar Pose from Orthography and Scaling with Iterations (COPOSIT), and an extended Kalman filter (EKF) estimates the state of an incoming aircraft during approach and landing at vertiports. Future work includes testing VIDIS in a high-fidelity simulation and with real-world data.
Distributed sensing↗
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Final ACT configuration evaluation
The Final ACT Configuration Evaluation Task of the Integrated Application of Active Controls (IAAC) technology project within the energy efficient transport program is summarized. The Final ACT Configuration, through application of Active Controls Technology (ACT) in combination with increased wing span, exhibits significant performance improvements over the conventional baseline configuration. At the design range for these configurations, 3590 km, the block fuel used is 10% less for the Final ACT Configuration, with significant reductions in fuel usage at all operational ranges. Results of this improved fuel usage and additional system and airframe costs and the complexity required to achieve it were analyzed to determine its economic effects. For a 926 km mission, the incremental return on investment is nearly 25% at 1980 fuel prices. For longer range missions or increased fuel prices, the return is greater. The technical risks encountered in the Final ACT Configuration design and the research and development effort required to reduce these risks to levels acceptable for commercial airplane design are identified.
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