A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center NASA/TM-2012-217450, E-18180 WBS 561581.02.08.03.45.02.04

Aircraft emissions currently account for ~3.5% of all greenhouse gas emissions. The number of passenger miles has increased by 5% annually despite 9/11, two wars and gloomy economic conditions. Since aircraft have no viable alternative to the internal combustion engine, improvements in aircraft efficiency and alternative fuel development become essential. This book comprehensively covers the relevant issues in green aviation. Environmental impacts, technology advances, public policy and economics are intricately linked to the pace of development that will be realized in the coming decades. Experts from NASA, industry and academia review current technology development in green aviation that will carry the industry through 2025 and beyond. This includes increased efficiency through better propulsion systems, reduced drag airframes, advanced materials and operational changes. Clean combustion and emission control of noise, exhaust gases and particulates are also addressed through combustor design and the use of alternative fuels. Economic imperatives from aircraft lifetime and maintenance logistics dictate the drive for "drop-in" fuels, blending jet-grade and biofuel. New certification standards for alternative fuels are outlined. Life Cycle Assessments are used to evaluate worldwide biofuel approaches, highlighting that there is no single rational approach for sustainable buildup. In fact, unless local conditions are considered, the use of biofuels can create a net increase in environmental impact as a result of biofuel manufacturing processes. Governmental experts evaluate current and future regulations and their impact on green aviation. Sustainable approaches to biofuel development are discussed for locations around the globe, including the US, EU, Brazil, China and India.

The NACA and aircraft propulsion, 1915-1958 -- NASA gets to work, 1958-1975 -- The shift toward commercial aviation, 1966-1975 -- The quest for propulsive efficiency, 1976-1989 -- Propulsion control enters the computer era, 1976-1998 -- Transiting to a new century, 1990-2008 -- Toward the future

A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot-Low-Speed Wind Tunnel (LSWT), and in two other aeroacoustic facilities. The Universal Propulsion Simulator (UPS) fan was designed and manufactured by the General Electric Aircraft Engines (GEAE) Company, and featured active core, as well as bypass, flow paths. The reference test configurations were with the metal, M4, rotor with hardwall and treated bypass flow ducts. The UPS fan was tested within an airflow at a Mach number of 0.20 (limited flow data were also acquired at a Mach number of 0.25) which is representative of aircraft takeoff and approach conditions. Comparisons were made between data acquired within the airflow (9x15 LSWT and German-Dutch Wind Tunnel (DNW)) and outside of a free jet (Boeing Low Speed Aero acoustic Facility (LSAF) and DNW). Sideline data were acquired on an 89-in. (nominal 4 fan diameters) sideline using the same microphone assembly and holder in the 9x15 LSWT and DNW facilities. These data showed good agreement for similar UPS operating conditions and configurations. Distortion of fan spectra tonal content through a free jet shear layer was documented, suggesting that in-flow acoustic measurements are required for comprehensive fan noise diagnostics. However, there was good agreement for overall sound power level (PWL) fan noise measurements made both within and outside of the test facility airflow. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center NASA/TM-2012-217608, E-18189 ACOUSTIC MEASUREMENT; AEROACOUSTICS; LOW SPEED WIND TUNNELS; TEST FACILITIES; TURBOFANS; WIND TUNNEL TESTS; AIRCRAFT MODELS; SIMULATORS; NOISE REDUCTION; SHEAR LAYERS; FREE JETS; FAN BLADES; AIR FLOW

This book puts the reader in the pilot's seat for a "day at the office" unlike any other. The Smell of Kerosene tells the dramatic story of a NASA research pilot who logged over 11,000 flight hours in more than 125 types of aircraft. Donald Mallick gives the reader fascinating first-hand description of his early naval flight training, carrier operations, and his research flying career with NASA. After transferring to the NASA Flight Research Center, Mallick became involved with projects that further pushed the boundaries of aerospace technology. These included the giant delta-winged XB-70 supersonic airplane, the wingless M2-F1 lifting body vehicle, and triple-sonic YF-12 Blackbird. Mallick also test flew the Lunar Landing Research Vehicle and helped develop techniques used in training astronauts to land on the Moon.

Green Aviation is the first authoritative overview of both engineering and operational measures to mitigate the environmental impact of aviation. It addresses the current status of measures to reduce the environmental impact of air travel. The chapters cover such items as: Engineering and technology-related subjects (aerodynamics, engines, fuels, structures, etc.), Operations (air traffic management and infrastructure) Policy and regulatory aspects regarding atmospheric and noise pollution. With contributions from leading experts, this volume is intended to be a valuable addition, and useful resource, for aerospace manufacturers and suppliers, governmental and industrial aerospace research establishments, airline and aviation industries, university engineering and science departments, and industry analysts, consultants, and researchers.