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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Open Cherry Picker simulation results

The Open Cherry Picker (OCP) is a manned platform, mounted at the end of the Remote Manipulator System (RMS), which is used to enhance extravehicular activities. The objective of the simulation program described was to reduce the existing complexity of those OCP design features that are mandatory for initial Space Shuttle applications. The OCP development test article consists of a torque box, a rotating foot restraint, a rotating stanchion that houses handholds, and a tool storage section with an interface with payload modules. If the size or complexity of the payload increases, payload handling devices may be added at a later data. The simulations have shown that the crew can control the RMS from the Aft Flight Deck of the Shuttle, using voice commands from the EVA crewman. No need for a stabilizer was evident, and RMS dynamics due to crew-induced workloads were found to be minor.

Nathan, C. A.↗
NASA NTRS1982

Shuttle entry GN&C performance during STS-1 and STS-2

Data obtained during the entry segment of the descent phase of the flights are analyzed. The nominal entry profile is defined and a description is given of the guidance, navigation, and control subsystem. Emphasis is placed on the stability and control problems encountered during STS-1 and to the changes made in response to these anomalies. These are: (1) the first roll maneuver was done manually at a reduced roll rate; (2) the nominal elevator position was changed from one degree up to one degree down for Mach numbers greater than 12 to reduce the heat load on the body flap; (3) the pilot was directed to execute small roll maneuvers at dynamic pressures of 4, 8, and 18 psf to help determine the roll moment from the aft yaw jets; (4) the planned test inputs in the transonic region were reduced in magnitude; and (5) the targeted touchdown point was moved 500 feet closer to the runway threshold.

Mcwhorter, L. B.↗
NASA NTRS1982

The relationship of motion sickness susceptibility to learned autonomic control for symptom suppression

Twenty-four men were randomly assigned to four equal groups matched in terms of their Coriolis Sickness Susceptibility Index (CSSI). Two groups of subjects were highly susceptible to motion sickness, and two groups were moderately susceptible. All subjects were given six C551 tests at 5-d intervals. Treatment Groups I (highly susceptible) and II (moderately susceptible) were taught to control their autonomic responses, using a training method called autogenic-feedback training (AFT) before the third, fourth, and fifth CSSI tests. Control groups III (highly susceptible) and IV (moderately susceptible) received no treatment. Results showed that both treatment groups significantly improved performance on CSSI tests after training; neither of the control groups changed significantly. Highly and moderately susceptible subjects in the two treatment groups improved at comparable rates. Highly susceptible control group subjects did not habituate across tests as readily as the moderately susceptible controls.

Cowings, P. S.↗
NASA NTRS1982

Refurbishment of SRB aluminum components by walnut hull blast removal of protective coatings

A test program was conducted to develop, optimize, and scale up an abrasive blasting procedure was developed for refurbishment of specific SRB components: aft skirt, forward skirt, frustrum, and painted piece parts. Test specimens utilizing 2219 T87 aluminum substrate of varying thicknesses were prepared and blasted at progressively increasing pressures with selected abrasives. Specimens were analyzed for material response. The optimum blasting parameters were determined on panel specimens and verified on a large cylindrical integrated test bed.

Colberg, W. R.↗
NASA NTRS1982

Investigation of installation effects of single-engine convergent-divergent nozzles

An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine installation effects on single-engine convergent-divergent nozzles applicable to reduced-power supersonic cruise aircraft. Tests were conducted at Mach numbers from 0.50 to 1.20, at angles of attack from -3 degrees to 9 degrees, and at nozzle pressure ratios from 1.0 (jet off) to 8.0. The effects of empennage arrangement, nozzle length, a cusp fairing, and afterbody closure on total aft-end drag coefficient and component drag coefficients were investigated. Basic lift- and drag-coefficient data and external static-pressure distributions on the nozzle and afterbody are presented and discussed.

Burley, J. R., II↗
NASA NTRS1981

Experimental investigation of tangential blowing for control of the strong shock boundary layer interaction on inlet ramps

A 0.165-scale isolated inlet model was tested in the NASA Lewis Research Center 8-ft by 6-ft Supersonic Wind Tunnel. Ramp boundary layer control was provided by tangential blowing from a row of holes in an aft-facing step set into the ramp surface. Testing was performed at Mach numbers from 1.36 to 1.96 using both cold and heated air in the blowing system. Stable inlet flow was achieved at all Mach numbers. Blowing hole geometry was found to be significant at 1.96M. Blowing air temperature was found to have only a small effect on system performance. High blowing levels were required at the most severe test conditions.

Schwendemann, M. F.↗
NASA NTRS1982

Processing composite materials

The fabrication of several composite structural articles including DC-10 upper aft rudders, L-1011 vertical fins and composite biomedical appliances are discussed. Innovative composite processing methods are included.

R. M. Baucom↗
NASA NTRS1982

Turbulence effect on crossflow around a circular cylinder at subcritical Reynolds numbers

An investigation of the effect of freestream turbulence on the flow around a smooth circular cylinder at subcritical Reynolds numbers from 5.2 x 10 to the 4th power to 2.09 x 10 to the 5th power was conducted. Measurements show that the interaction of incident turbulence with the initial laminar boundary layer: (1) modifies the characteristics of the mean surface pressure distribution; (2) induces an aft shift in the separation point ranging from 5 to 50 beyond the laminar separation angle of 80 degrees; and, (3) reduces the mean drag coefficient to values between 97 and 46% of its nearly constant laminar counterpart. The extent of these changes depends on the particular Reynolds number background turbulence combination. These results demonstrate that a boundary-layer flow similar to that found in critical, supercritical and/or transcritical flow regimes is induced by turbulence at subcritical Reynolds numbers and, hence, the effect of turbulence is equivalent to an effective increase in the Reynolds number. The change in the nature and properties of the boundary layer in the subcritical regime, consequent upon the penetration of turbulence into it, is in agreement with the model proposed by the vorticity-amplification theory.

Sadeh, W. Z.↗
NASA NTRS1982

Wind tunnel tests of a free-wing/free-trimmer model

The riding qualities of an aircraft with low wing loading can be improved by freeing the wing to rotate about its spanwise axis. A trimming surface also free to rotate about its spanwise axis can be added at the wing tips to permit the use of high lift devices. Wind tunnel tests of the free wing/free trimmer model with the trimmer attached to the wing tips aft of the wing chord were conducted to validate a mathematical model developed to predict the dynamic characteristics of a free wing/free trimmer aircraft. A model consisting of a semispan wing with the trimmer mounted on with the wing on an air bearing and the trimmer on a ball bearing was displaced to various angles of attack and released. The damped oscillations of the wing and trimmer were recorded. Real and imaginary parts of the characteristic equations of motion were determined and compared to values predicted using the mathematical model.

Sandlin, D. R.↗
NASA NTRS1981

Powder metallurgy Rene 95 rotating turbine engine parts, volume 2

A Rene 95 alloy as-HIP high pressure turbine aft shaft in the CF6-50 engine and a HIP plus forged Rene 95 compressor disk in the CFM56 engine were tested. The CF6-50 engine test was conducted for 1000 C cycles and the CFM56 test for 2000 C cycles. Post test evaluation and analysis of the CF6-50 shaft and the CFM56 compressor disk included visual, fluorescent penetrant, and dimensional inspections. No defects or otherwise discrepant conditions were found. These parts were judged to have performed satisfactorily.

Wilbers, L. G.↗
NASA NTRS1982

Effects of noise radiated from convected ring sources in coaxial dual flow. Part 1: The noise from unheated jets

The effects of flight on sound radiated from embedded, uncorrelated ring sources convecting along the midst of the primary and the secondary streams of a coaxial dual flow which emerges from a moving nozzle into the ambience are studied. Cold jets are examined. The problem is posed as a double vortex-sheet flow model which involves deliberate suppression of inherent instabilities of the flow and is formulated, as a linear problem, in terms of the combined contributions of two independent uncorrelated quadrupole-type ring sources, the one convecting in the primary flow representing the sources generated due to the interaction at the primary/secondary interface and the other convecting in the secondary flow representing the sources generated due to the interaction at the secondary/ambient interface. The analysis shows that the effects of flight induce (1) amplication of noise in the forward quadrant, (2) reduction of noise in the aft quadrant and (3) absolutely no impact on radiation of noise at Theta = 90 deg to the jet axis.

Dash, R.↗
NASA NTRS1983

The minimization of pylon-mounted store effects on air combat capability

Some effects of pylon-mounted missiles on aft-tail delta wing supersonic fighter concepts have been investigated. Whereas minimum drag penalties do occur with the addition of missiles, the effects at higher lifts, corresponding to maneuvering flight, are less severe and often favorable. Lower speeds and altitudes enhance the maneuvering capability and one-on-one air combat would probably tend to degenerate to subsonic speeds even though the combatants may be flying supersonic fighters. Higher speed (supersonic) flight might best be reserved for interceptors with long-range missiles where the weapon carriage effects at low angles of attack are of prime importance.

Spearman, M. L.↗
NASA NTRS1983

An aerodynamic assessment of various supersonic fighter airplanes based on Soviet design concepts

The aerodynamic, stability, and control characteristics of several supersonic fighter airplane concepts were assessed. The configurations include fixed-wing airplanes having delta wings, swept wings, and trapezoidal wings, and variable wing-sweep airplanes. Each concept employs aft tail controls. The concepts vary from lightweight, single engine, air superiority, point interceptor, or ground attack types to larger twin-engine interceptor and reconnaissance designs. Results indicate that careful application of the transonic or supersonic area rule can provide nearly optimum shaping for minimum drag for a specified Mach number requirement. Through the proper location of components and the exploitation of interference flow fields, the concepts provide linear pitching moment characteristics, high control effectiveness, and reasonably small variations in aerodynamic center location with a resulting high potential for maneuvering capability. By careful attention to component shaping and location and through the exploitation of local flow fields, favorable roll-to-yaw ratios may result and a high degree of directional stability can be achieved.

Spearman, M. L.↗
NASA NTRS1983

Effects of twin-vertical-tail parameters on twin-engine afterbody/nozzle aerodynamic characteristics

The Langley 16-foot transonic tunnel was used to determine the effects of several empennage and afterbody parameters on twin-engine aft-end aerodynamic characteristics. Model variables included twin-vertical-tail cant angle, toe angle, airfoil camber, and root-chord length and afterbody/engine interfairing shape. Tests were conducted over a Mach number range from 0.6 to 1.2 and over an angle-of-attack range from 2 deg to 10 deg. Nozzle pressure ratio was varied from 1.0 (jet off) to approximately 10.0.

Leavitt, L. D.↗
NASA NTRS1983

A simulation study of crew performance in operating an advanced transport aircraft in an automated terminal area environment

A simulation study assessing crew performance operating an advanced transport aircraft in an automated terminal area environment is described. The linking together of the Langley Advanced Transport Operating Systems Aft Flight Deck Simulator with the Terminal Area Air Traffic Model Simulation was required. The realism of an air traffic control (ATC) environment with audio controller instructions for the flight crews and the capability of inserting a live aircraft into the terminal area model to interact with computer generated aircraft was provided. Crew performance using the advanced displays and two separate control systems (automatic and manual) in flying area navigation routes in the automated ATC environment was assessed. Although the crews did not perform as well using the manual control system, their performances were within acceptable operational limits with little increase in workload. The crews favored using the manual control system and felt they were more alert and aware of their environment when using it.

Houck, J. A.↗
NASA NTRS1983

Intumescent coating development

A program was completed at the University of Dayton Research Institute in which polyimide and phenolic intumescent coatings were evaluated as supplemental thermal insulation for the sprayed-on foam insulation on the aft bulkhead of the space shuttle external tank. The purpose of the intumescent coating was to provide additional thermal protection during lift-off in order to replace the ablative heat resistant layer with a lighter weight material for increased payload in the shuttle.

Sayler, I. O.↗
NASA NTRS1983

Rolling Beam Umbilical System

The decision to make the Centaur Vehicle a Space Transportation System (STS) payload meant that new ground support equipment provisions at Launch Pads Pads 39A and 39B were required. These new equipment provisions were needed to service the Centaur vehicle while it was installed in the Orbiter's payload bay prior to launch. This paper describes the design of a new rolling beam umbilical syste (RBUS) being added to the pad fixed service structure (FSS) in order to provide the primary functions of liquid hydrogen (LH2) fill, drain, and vent. The carrier plate itself is a Government-furnished equipment item and of necessity became a T-O disconnect. This permits quick offloading in the event of an abort prior to lift-off. In addition to the rolling beam structure, mechanisms, and fluid lines, it was necessary to design and build a carrier plate simulator to support early development testing of the mast at the Launch Equipment Test Facility at Kennedy Space Center. The RBUS is designed to be compatible with the rotating service structure (RSS) to the extent that the umbilical may be deployed with the RSS mated with the vehicle. It is also designed to clear the RSS as the RSS rotates back out of the way. Accessibility to the Orbiter aft compartment via the 50-1 door had to be maintained.

Tatem, B. C., Jr.↗
NASA NTRS1983

Effect of empennage location on twin-engine afterbody-nozzle aerodynamic characteristics at Mach Numbers from 0.6 to 1.2

The Langley 16-foot transonic tunnel was used to determine the effects of several empennage and afterbody parameters on the aft-end aerodynamic characteristics of a twin-engine fighter-type configuration. Model variables were as follows: horizontal tail axial location and incidence, vertical tail axial location and configuration (twin- versus single-tail arrangements), tail booms, and nozzle power setting. Tests were conducted over a Mach number range from 0.6 to 1.2 and over an angle-of-attack from -2 deg to 10 deg. Jet total-pressure ratio was varied from jet off to approximately 10.0.

Leavitt, L. D.↗