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At least 415 records · Page 23

Alloy composition effects on oxidation products of VIA, B-1900, 713C, and 738X: A high temperature diffractometer study

High temperature X-ray diffraction studies were performed to investigate isothermal and cyclic oxidation at 1000 and 1100 C of the nickel-base superalloys VIA, B-1900, 713C, and 738X. Oxidation was complex. The major oxides, Al2O3, Cr2O3, and the spinels, formed in amounts consistent with alloy chemistry. The alloys VIA and B-1900 (high Al, low Cr alloys) tended to form Al2O3 and NiAl2O4; 738X (high Cr, low Al) formed Cr2O3 and NiCr2O4. A NiTa2O6 type of oxide formed in amounts approximately proportional to the refractory metal content of the alloy. One of the effects of cycling was to increase the amount of spinels formed.

Garlick, R. G.↗

An evaluation of the relative fire hazards of jet A and jet B for commercial flight

The relative fire hazards of Jet A and Jet B aircraft fuels are evaluated. The evaluation is based on a consideration of the presence of and/or the generation of flammable mixtures in fuel systems, the ignition characteristics, and the flame propagation rates for the two fuel types. Three distinct aircraft operating regimes where fuel type may be a factor in fire hazards are considered. These are: (1) ground handling and refueling, (2) flight, and (3) crash. The evaluation indicates that the overall fire hazards for Jet A are less than for Jet B fuel.

Hibbard, R. R.↗

MSFC Sortie Laboratory Environmental Control System (ECS) phase B design study results

Phase B effort of the Sortie Lab program has concluded. Results of that effort are presented which pertain to the definitions of the environmental control system (ECS). Numerous design studies were performed in Phase B to investigate system feasibility, complexity, weight, and cost. The results and methods employed for these design studies are included. An autonomous Sortie Lab ECS was developed which utilizes a deployed space radiator. Total system weight was projected to be 1814.4 kg including the radiator and fluids. ECS power requirements were estimated at 950 watts.

Ignatonis, A. J.↗

Laser measurements of the radiative lifetime of the B state of CN

A turnable dye laser was used to measure the radiative lifetime of the individual rotational levels of the B2 Sigma (+) state of CN. The radiative lifetime of the unperturbed rotational levels is 65.6 plus or minus 1.0 nsec. A longer radiative lifetime of 72 plus or minus 1 nsec is observed for the Kaon prime = 4 level of the B state. The measured values of the perturbed and unperturbed levels support the longer lifetimes for the A2 meson pion state of CN. The quenching cross section of the B2 Sigma state of CN is 41 plus or minus 20 Angstroms squared and is independent of the rotational energy of the B state.

Jackson, W. M.↗

Dynamic oxidation behavior at 1000 and 1100 C of four nickel-base cast alloys, NASA-TRW VIA, B-1900, 713C, and 738X

The superalloys NASA-TRW VIA, B-1900, 713C, and 738X were tested cyclically and isothermally for resistance to oxidation in high velocity gas streams for 100 hours at specimen temperatures of 1000 C and 1100 C. Alloys VIA and B-1900, which were the most oxidation resistant, displayed slight and very similar weight changes and metal losses. Alloy 713C also sustained only slight metal losses, but it exhibited some tendency to spall. Alloy 738X was found to be the most susceptible to cyclic oxidation; this resulted in heavy spalling, which in turn caused high weight losses and high metal losses. Oxidation test results are related to the amounts of chromium aluminum, and the refractory metals in the alloys investigated.

Sanders, W. A.↗

Results of investigations (OA77 and OA78) on an 0.015-scale 140A/B configuration space shuttle vehicle orbiter model 49-0 in the AEDC VKF B and C wind tunnels, revision A

Aerodynamic data obtained from wind tunnel tests of an 0.015-scale 140A/B configuration SSV Orbiter model in the AEDC VKF B and C wind tunnels are presented. Tests were conducted at Mach numbers of 6 and 8 in the B tunnel and at a Mach number of 10 to in the C tunnel to verify hypersonic stability and control characteristics, determine control surface effectiveness, and investigate Reynolds number effects of the 140A/B configuration. Force data were obtained for various control surface settings and Reynolds numbers in the angle-of-attack range of 15 deg to 45 deg and at angles of sideslip of -5 deg to +10 deg. Data were obtained for a few configurations at angles of attack from -27 deg to 45 deg. Control surface variables included elevon, rudder, speedbrake and bodyflap deflections. The effects of an alternate wing leading edge shape were investigated to determine its hypersonic stability and control characteristics.

Gillins, R. L.↗

B-52 stability augmentation system reliability

The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability.

Bowling, T. C.↗

Hot corrosion studies of four nickel-base superalloys: B-1900, NASA-TRW VIA, 713C and IN738

The susceptibility to hot corrosion of four nickel base superalloys has been studied at 900 deg and 1000 deg C in one atmosphere of slowly flowing oxygen. Hot corrosion was induced by coating the samples with known doses of NaSO4 and oxidizing the coated samples isothermally on a sensitive microbalance. In general, the order of susceptibility found was: B-1900 is greater than 713C is greater than NASA-TRW VIA and is greater than IN738. This order corresponds to the order of decreasing molybdenum content of the alloys. Chemical evidence for B-1900 indicates that hot corrosion is instigated by acid fluxing of the protective Al2O3 coating by MoO3.

Fryburg, G. C.↗

A description of the software analysis from flight and simulation data of the course cut limiter in the TCV b-737 area navigation computer

During automatic horizontal path captures, the (Terminal Configured Vehicle) B-737 airplane maintained smaller than designed path intercept angles and experienced a sawtooth bank angle oscillation during its turn towards the path. From flight data, it was determined that these anomalies were caused by the improper output of the course cut limiter in the horizontal path control law. The output from the course cut limiter did not obtain its full value and it was calculated stepwise discontinuously. The automatic horizontal path captures were then conducted on the TCV B-737 airplane real-time simulation. The path intercept angles were maintained properly and no bank angle oscillation was encountered. Data showed that the course cut limiter was calculated at its full value in a continuous manner. The intermediate calculations of the course cut limiter in the airplane's navigation computer were rewritten and rescaled in such a manner that truncation errors could be minimized. The horizontal path capture tests were then reflown. The airplane maintained the proper path intercept angle and no bank angle oscillations occurred on any of the tests.

Knox, C. E.↗

The behavior of the Mg II doublet features near 2800 A observed in F, A, and B supergiants

The Mg II doublet features near 2800 A were recently observed in F-, A-, and B-type supergiants with a balloon-borne ultraviolet stellar spectrometer. The stars observed are Alpha UMi (F8 Ib), Alpha Per (F5 Ib), Eta Leo (A0 Ib), and Rho Leo (B1 Ib). The Mg II doublet features in Alpha UMi and Alpha Per show emission superposed on photospheric absorption. In the spectrum of Eta Leo, the Mg II lines are in absorption and show shortward-shifted components attributable to mass loss. In the spectrum of Rho Leo, the Mg II lines are primarily a composite of the photospheric and interstellar absorption features. The general behavior of the Mg II lines for supergiants of spectral types M through B are also discussed.

Kondo, Y.↗

Hot corrosion studies of four nickel-base superalloys - B-1900, NASA-TRW VIA, 713C and IN738

The susceptibility to hot corrosion of four nickel-base superalloys has been studied at 900 and 1000 C in one atmosphere of slowly flowing oxygen. Hot corrosion was induced by coating the samples with known doses of Na2SO4 and oxidizing the coated samples isothermally on a sensitive microbalance. In order of decending susceptibility to hot corrosion, these alloys were ranked: B-1900, 713C, NASA-TRW VIA, IN738. This order corresponds to the order of decreasing molybdenum content of the alloys. Chemical evidence for B-1900 indicates that hot corrosion is instigated by acid fluxing of the protective Al2O3 coating by MoO3.

Fryburg, G. C.↗

Guide star targeting success for the HEAO-B observatory

The statistics associated with the successful selection and acquisition of guide stars as attitude benchmarks for use in reorientation maneuvers of the HEAO-B observatory are considered as a function of the maneuver angle, initial attitude uncertainties, and the pertinent celestial region. Success likelihoods in excess of 0.99 are predicted assuming anticipated gyro and star tracker error sources. The maneuver technique and guide star selection constraints are described in detail. The results presented are specialized numerically to the HEAO-B observatory. However, the analytical techniques developed are considered applicable to broader classes of spacecraft requiring celestial targeting.

Farrenkopf, R. L.↗

Simultaneous measurements of ozone outside and inside cabins of two B-747 airliners and a Gates Learjet business jet

The average amount of ozone measured in the cabins of two B-747 airliners varied from 40 percent to 80 percent of the atmospheric concentrations without special ozone destruction systems. A charcoal filter in the cabin air inlet system of one B-747 reduced the ozone to about 5 percent of the atmospheric concentration. A Learjet 23 was also instrumented with monitors to measure simultaneously the atmospheric and ozone concentrations. Results indicate that a significant portion of the atmospheric ozone is not destroyed in the pressurization system and remains in the aircraft cabin of the Learjet. For the two cabin configurations tested, the ozone retentions were 63 and 41 percent of the atmospheric ozone concentrations. Ozone concentrations measured in the cabin near the conditioned-air outlets were reduced only slightly from atmospheric ozone concentrations. It is concluded that a constant difference between ozone concentrations inside and outside the cabin does not exist.

Perkins, P. J.↗

Experimental differential and integral electron impact cross sections for the B /1-Sigma-u +/ state of H2 in the intermediate-energy region

Utilizing a crossed electron-beam-molecular-beam scattering technique, differential electron impact cross sections (DCS) for the excitation of the nu prime = 2 vibrational band of the B (1-Sigma-u +) state of H2 have been measured and are presented for the first time. These measurements were made at electron impact energies of 15, 20, 30, 40, 50 and 60 eV. At each energy, DCS between scattering angles of 10 and 135 deg were determined. They were then extrapolated to 0 and 180 deg scattering angles to obtain the integral cross sections. These integral cross sections and the Frank-Condon factor for the nu prime = 2 band were used to calculate the total cross sections for the excitation of the B (1-Sigma-u +).

Srivastava, S. K.↗

The HEAO-B Monitor Proportional Counter Instrument

The Monitor Proportional Counter Instrument for the HEAO-B X-ray Telescope satellite is designed to observe celestial X-ray sources in the range of 1 to 20 keV with intensities exceeding .0002 Crab. It provides both spectral and temporal data, to complement the data from the other HEAO-B instruments, to compare with observations from previous flights, as well as to allow detailed study of time variant X-ray phenomena. The basic detector is a large area proportional counter system, consisting of two counters, high voltage power supplies and preamplifiers, mounted behind a collimator with a 2/3 degree square field of view. The signal processing, power distribution and control electronics are contained in a separate unit, which includes circuitry to perform pulse height analysis, background rejection, time interval measurement, redundancy switching and control, housekeeping and telemetry interfacing.

Gaillardetz, R.↗

The curved crystal X-ray spectrometer for the HEAO-B satellite

The Focal Plane Crystal Spectrometer on HEAO-B is a moderate to high resolution, curved-crystal, Bragg spectrometer which operates behind a grazing incidence X-ray telescope. It is designed to allow detailed spectral studies of both point and extended celestial X-ray sources in the energy range 0.2-3.3 keV, with resolutions of 50 to 1000. The analyzing elements are six torroidal diffractors, and the detectors are position-sensitive, flow, proportional counters. HEAO-B is scheduled for launch in June, 1978.

Canizares, C. R.↗

Load and dynamic assessment of B-52B-008 carrier aircraft for finned configuration 1 space shuttle solid rocket booster decelerator subsystem drop test vehicle. Volume 1: Summary

The B-52B airplane was identified for use in solid rocket booster (RSB) parachute drop flight testing. The purpose of this study was to determine by theoretical analysis methods the compatability and structural capability of B-52B drop test vehicle configuration (with fins) to accomplish the drop test mission. This document consist of four volumes. This volume presents a summary of airplane flutter and load strength evaluation analysis results and a comparative study of the pylon loading resulting from drop test vehicle inertia and aerodynamic considerations.

Quade, D. A.↗

FLTSATCOM-B launch

The prelaunch mission operation report of the Fleet Satellite Communications System (FLTSATCOM-B) spacecraft is presented. The orbit requirements, mission profiles, parking orbit, and transfer orbit for the FLTSATCOM-B spacecraft are described.

Yardley, J. F.↗