SEARCH · Search NASA
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Thermophysical property measurements on ablative materials for Apollo spacecraft propulsion system configuration
Aircraft technologies related to conventional and vertical takeoff and landing /VTOL/ flight modes, vehicle configuration, and propulsion systems
Air breathing launch vehicle for earth-orbit shuttle assessed in light of hypersonic propulsion and configuration development
Shrouded composite propulsion system configuration
Trajectory profiles and nuclear propulsion vehicle configurations for manned Mars and Mars-Venus missions
Propulsion system configurations and hydrogen oxygen engines for space shuttles
Effects of engine design and propulsion system configurations on combustion efficiency
The development of scientific satellites is briefly discussed with emphasis on exhaust velocity enhancement by various propulsion system configurations. Also reported is the experimental production of artificial auroras at points separated by thousands of miles over the earth by creating relativistic electrons.
The YF-12 research program was initiated to establish a technology base for the design of an efficient propulsion system for supersonic cruise aircraft. The major technology areas under investigation in this program are inlet design analysis, propulsion system steady-state performance, propulsion system dynamic performance, inlet and engine control systems, and airframe/propulsion system interactions. The objectives, technical approach, and status of the YF-12 propulsion program are discussed. Also discussed are the results obtained to date by the NASA Ames, Lewis, and Dryden research centers. The expected technical results and proposed future programs are also given. Propulsion system configurations are shown.
Fuel conservation that could be attained with two technology advancements, Q fan propulsion system and active control technology (ACT) was studied. Aircraft incorporating each technology were sized for a Federal Aviation Regulation (FAR) field length of 914 meters (3,000 feet), 148 passengers, and a 926 kilometer (500 nautical mile) mission. The cruise Mach number was .70 at 10100 meter (33,000 foot) altitude. The improvement resulting from application of the Q fan propulsion system was computed relative to an optimized fuel conservative transport design. The performance improvements resulting from application of ACT technology were relative to the optimized Q fan propulsion system configuration.
While at this point in time no particular propulsion system configuration has been chosen for the V/STOL Type A, many combinations of number of fans, gas generators, and methods of power interconnection have been investigated. Low pressure systems under consideration include variable pitch and variable inlet guide vanes for thrust modulation, geared and direct turbine drive, and shaft and gas power transfer systems. Several of these features are being studied in the Quiet, Clean, Short-Haul, Experimental Engine (QCSEE) program, which is developing the technology needed for future short-haul passenger aircraft. Test status and key characteristics of QCSEE engines and their components are discussed in detail.
This paper is intended to provide an overview of the air transportation system for the year 2000 in terms of vehicle expectations. Emphasis is placed on civil air transportation with the time period approached from the standpoint of evolutionary changes for the near term and also with the assumption of more revolutionary changes for the far term. The view along the evolutionary path begins with a historical review of airline market growth and the impact that technologies have had on airplane designs. Projections of the life expectancy of existing, derivative, and new airplanes are examined in terms of their productivity and fuel efficiency in view of the present and projected fuel usage and availability. The factors influencing airline growth are outlined and some views on whether another new generation of subsonic airplanes are in the offing are given along with an assessment of the economic viability of an advanced commercial supersonic transport in terms of its higher speed, higher productivity, and higher fuel usage. With regard to revolutionary changes, major technology breakthroughs are assumed to occur at a specified date. As an example, the impact of a dramatic reduction in skin friction drag is examined in terms of its effect on the airplane configuration, its propulsion systems, it projected fuel usage, and the air transportation system in which it must operate.
Low thrust chemical (hydrogen-oxygen) propulsion systems configured specifically for low acceleration orbit transfer of large space systems were defined. Results indicate that it is cost effective and least risk to combine the OTV and stowed spacecraft in a single 65 K Shuttle. The study shows that the engine for an optimized low thrust stage (1) does not require very low thrust; (2) 1-3 K thrust range appears optimum; (3) thrust transient is not a concern; (4) throttling probably not worthwhile; and (5) multiple thrusters complicate OTV/LSS design and aggravate LSS loads. Regarding the optimum vehicle for low acceleration missions, the single shuttle launch (LSS and expendable OTV) is most cost effective and least risky. Multiple shuttles increase diameter 20%. The space based radar structure short OTV (which maximizes space available for packaged LSS) favors use of torus tank. Propellant tank pressures/vapor residuals are little affected by engine thrust level or number of burns.
The technological advances most likely to contribute to advanced aircraft designs and the efficiency, performance, and financial considerations driving the development directions for new aircraft are reviewed. Fuel-efficiency is perceived as the most critical factor for any new aircraft or component design, with most gains expected to come in areas of propulsion, aerodynamics, configurations, structural designs and materials, active controls, digital avionics, laminar flow control, and air-traffic control improvements. Any component area offers an efficiency improvement of 3-12%, with a maximum of 50% possible with a 4000 m range aircraft. Advanced turboprops have potential applications in short and medium haul subsonic aircraft, while a fuel efficient SST may be possible by the year 2000. Further discussion is devoted to the pivoted oblique wing aircraft, lightweight structures, and the necessity for short payback times.
An assessment is made of the development possibilities of aerospace vehicle materials and structures, propulsion, avionics, configurations, computerized simulation, and operational capabilities. The supersonic transports envisioned for the 21st century would incorporate advanced, high temperature material structural design techniques, and a variable-cycle engine technology capable of a 40 percent increase in cruise efficiency over current systems, combined with low takeoff noise and efficient subsonic operation. This technology, as well as that of tilt-rotor VTOL aircraft which will be able to cruise at speeds comparable to those of present fixed-wing aircraft, are directly applicable to military systems. The impact of microelectronics and computer technologies on both avionics and the computational simulation of three-dimensional aerodynamic characteristics are also noted as important prospective developments.
Wind tunnel tests were conducted of a scale model of the Aladin 2 aircraft. The propulsion system configuration is described and the air flow caused by jet ejection is analyzed. Three dimensional flow studies in the vicinity of the engine installation were made. Diagrams of the leading and trailing edge flaps are provided. Graphs are developed to show the aerodynamic performance under conditions of various airspeed and flap deflection.
Significant achievements and activities of Phase 2 of a study to assess aeroassisted orbit transfer vehicle (AOTV) system technology are summarized. Phase 2 was directed towards identification and prioritization of technology payoffs of representative space based mid lift/drag ratio (L/D) AOTV's and the cryofueled propulsion subsystem - configuration interactions. Enhancing technology areas were identified which could provide substantial transport cost reduction. These include: (1) improved lifetime of storable propellant engines; (2) avionics weight reduction; (3) external thermal protection system weight reduction; (4) decrease of uncertainties in aerodynamic and aerothermodynamic performance; electrical power subsystem weight reduction due to incorporation of advanced materials; and (6) structural shell weight reduction. Results indicated that advanced aerothermodynamic methodology and aft end configuring may provide an enlarged allowable zone for engine nozzle protrusions into the separated flow region. Payload manifesting and non-hydrogen propellant manifesting at the space station is recommended.