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  • MACHINE ELEMENTS AND PROCESSES  (2,755)
  • AERODYNAMICS
  • 1970-1974  (2,458)
  • 1965-1969  (2,552)
  • 1925-1929  (1)
Collection
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Years
Year
  • 1
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    Noise control of pneumatic percussion drills (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Noise sources in pneumatic drills are studied bringing to light the fact that air exhaust is the most important source. The present state of the art of noise control is discussed for pneumatic percussion drills abroad, indicating the different solutions adopted in this respect. Drills produced in Rumania are described and the results of noise measurements are shown.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 177-181
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  • 2
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    Contributions to the study of the characteristics of bearing noise and vibrations (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Results of experimental research on the noise and vibrations of radial ball and roller bearings are reported. Analysis of the frequency spectra disclosed dependences among vibration and noise, load, rpm and cage material. Some peculiar aspects of the frequency spectrum are also mentioned.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 131-135
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  • 3
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    Aspects of reducing spur gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Noise sources in gears and ways of improving their silence by profile shape alterations and wheel surface smoothness are discussed. Practical results obtained, from the noise point of view are reported, for textile machinery.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 124-130
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  • 4
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    Contributions to the reduction of gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The influence of profile displacements on the acoustic pressure level of running gears is studied. The conclusion is reached that extra polar gears function well, reducing the acoustic pressure level by about 2-3 db which, at the level of the total noise of 80-90 db, can be easily felt. This result can be explained by the fact that in this gear the pitch point is situated outside of the gearing segment, so that a certain change in the direction of the friction force between the tooth flanks is eliminated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 118-123
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  • 5
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    Load influence on gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: An original mathematical model is proposed to derive equations for calculation of gear noise. These equations permit the acoustic pressure level to be determined as a function of load. Application of this method to three parallel gears is reported. The logical calculation scheme is given, as well as the results obtained.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 112-117
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  • 6
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    Preliminary study of gear noise characteristics (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Experimental results and conclusions are presented about the noise characteristics of gears as a function of their operating conditions. The interpretive possibilities offered by real time noise and vibration spectrum analysis are emphasized. The noise reducing effects of light weight insulation boxes are also discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 104-111
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  • 7
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    Considerations on the acoustic energy radiated by toothed gears (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 98-103
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  • 8
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    Acoustic determination of cracks in welded joints (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The acoustic analysis method permits detection of any cracks that might take place and their manner of propagation. The study deals with the cracks produced in experiments to determine the welding technology for a welded gray cast iron workpiece by using piezoelectric transducers to determine vibration acceleration.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 93-97
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  • 9
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    US studies in the field of shaft drilling on the lunar surface (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: American equipment for drilling in the lunar surface is discussed, with emphasis on rotary-percussive methodology and core-sample retrieval techniques.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 192-205
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  • 10
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    Lifting-surface theory for a semi-infinite wing in oblique gust (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: An unsteady lifting-surface theory is developed for the calculation of the airload on a semi-infinite-span thin wing in a compressible flow due to interaction with an oblique gust. By using the solutions obtained for a two-dimensional wing, the problem is formulated so that the unknown is taken to be the difference between the airload on the semi-infinite wing and that on a two-dimensional wing under the same gust conditions. Since this airload difference is nonzero only near the wing tip, the control points need be distributed in the tip region only; this significantly simplifies the numerical procedure. Results are presented for a wing with rectangular tip. The implication for noise and unsteady loads due to blade-vortex interaction for helicopter rotors is discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Dec. 197
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  • 11
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    Planetary entry aerothermodynamics. II - Computational analyses and flight experience (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Limitations concerning the possibility to simulate all the significant flow and thermal phenomena occurring during the entry of a space vehicle into a planetary atmosphere make it necessary to rely on computational analyses to obtain the required data for the design of the spacecraft needed for the NASA missions planned for the next two decades. 'Benchmark' computer programs concerned with complete, detailed, and accurate computational solutions of entry problems are considered along with programs representing engineering approximations for cases in which the accuracy provided by the benchmark programs is not needed. The information obtainable by computational analysis has to be supplemented by actual flight experience in order to meet the goals of the NASA entry-technology program. The individual space missions planned for the coming years are examined together with the possibilities for obtaining the data needed to satisfy the entry requirements in each case.
    Keywords: AERODYNAMICS
    Type: Astronautics and Aeronautics; 12; Dec. 197
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  • 12
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    Induction brazing at the Kennedy Space Center (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: A description of the joint design, materials, equipment, qualification testing, inspection methods, and applications involved in performing induction brazing on hyperbolic propellants tubing at Kennedy Space Center. Induction brazing is a form of brazing in which the energy is transmitted to the workpiece by electrical induction; the eddy currents generated in the metal produce heat by resistance losses. Since induction heating is fast and highly localized, undesirable heat effects are minimized and the resulting braze is of high quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 13
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    Analysis of acoustic radiation in a jet flow environment (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The analysis of sound fields from arbitrary source distributions in terms of Legendre and spherical Hankel functions is well known. The purpose of this paper is to extend this classical method of analysis to environments such as jet flows where flow and flow gradients are inherently present. The wave-equation governing the radiation of sound in such an environment is derived. The steady state flow and flow gradients in the axial and transverse directions appear as coefficients in the terms of the wave-equation. A semi-numerical method is used to solve the wave-equation in terms of modified spherical harmonics yielding the phase velocities and the directivities of an infinite set of modes. The directivity of each mode is obtained in terms of modified Legendre functions by numerical integration. Some results of these directivity and phase-velocity calculations are presented for a limited number of frequency and flow parameters. Both convective and shear refraction are shown to be important.
    Keywords: AERODYNAMICS
    Type: Journal of Sound and Vibration; 36; Sept. 8
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  • 14
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    Unified approach to aerodynamic sound generation in the presence of solid boundaries (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A general equation governing aerodynamic sound generation in the presence of solid boundaries is derived. It is shown that all the theories in the literature appear as special cases of this general equation. Derived special equations for propeller and fan noise are likewise shown to be more general than the conventional equations in that they make allowance for variation in retarded time over the blade surfaces.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 15
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    Impact testing on composite fan blades (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: SAMPE Quarterly; 5; July 197
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  • 16
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    Automatic numerical generation of body-fitted curvilinear coordinate system for field containing any number of arbitrary two-dimensional bodies (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: A method for automatic numerical generation of a general curvilinear coordinate system with coordinate lines coincident with all boundaries of a general multi-connected region containing any number of arbitrarily shaped bodies is presented. With this procedure the numerical solution of a partial differential system may be done on a fixed rectangular field with a square mesh with no interpolation required regardless of the shape of the physical boundaries, regardless of the spacing of the curvilinear coordinate lines in the physical field, and regardless of the movement of the coordinate system. Numerical solutions for the lifting and nonlifting potential flow about Joukowski and Karman-Trefftz airfoils using this coordinate system generation show excellent comparison with the analytic solutions. The application to fields with multiple bodies is illustrated by a potential flow solution for multiple airfoils.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; July 197
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  • 17
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    Analysis of propagation of waves of acoustic frequencies in curved ducts (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The propagation of waves of acoustic frequencies in curved ducts of rectangular cross section is studied for the first four modes. The analysis makes use of Bessel functions of the order (n + 1/2) to construct curves of wavenumber in the duct versus imposed wavenumber and to determine the profile of vibrational velocities. A wide range of duct widths and unrestricted radii of curvature have been considered. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 18
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    Sealing of large leaks in high-vacuum systems subject to mechanical and thermal stresses (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The use of silicone rubber adhesive (particularly, G.E. RTV-108) for sealing large leaks in high vacuum systems subject to mechanical and thermal stresses is shown to be more effective than that of epoxy cements. The sealant is applied externally to the leak while the system is partially evacuated so that it is drawn into the hole.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Vacuum Science and Technology; 11; July-Aug
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  • 19
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    Axial flow measurements in trailing vortices (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A scanning laser Doppler velocimeter was used to measure the axial velocity defect in the cores of trailing vortices behind a lifting airfoil of rectangular planform. Data were obtained at several different angles of attack and downstream distances ranging from 30 to 1000 chord lengths. The test was designed to obtain continuous data from the near field into the far field while removing uncertainties associated with the interpretation of data obtained by the hydrogen bubble technique. The measured velocities of V sub x/U sub infinity are compared with those predicted. The agreement is remarkably good over the entire range of downstream distances, which supports the credibility of calculating axial velocities using the results of Moore and Saffman (1973).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Aug. 197
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  • 20
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    Aluminized alloy boosts turbine blade life (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Description of an aluminized alloy coating technique that involves first the application of a ductile, oxidation-resistant overlay, such as NiCrAl, which is then partially aluminized. The duplex protective system has performance advantages over conventional aluminide coatings in that it provides higher-temperature hot corrosion resistance over a longer service life.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Metal Progress; 106; Aug. 197
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  • 21
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    Vortex measurements behind a swept wing transport model (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A backscatter laser Doppler velocimeter which simultaneously senses the axial and the tangential components of the velocity has been used to measure the velocity distributions in the near wake of a swept wing semispan transport model in a wind tunnel. The model configuration included nacelles, pylons, antishock bodies, and wing flaps which could be deflected 27 deg. Typical wake vortex velocity profiles are presented for the flaps-retracted and the flaps-deployed 27 deg configurations, respectively.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; June 197
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  • 22
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    Friction and friction-generated temperature at a polymer-metal interface (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Results of friction and thermal tests of molded polyimide and pyrrone polymers are presented. The coefficient of sliding friction up to surface velocities of 2 m/sec and the coefficient of thermal expansion from 300 to 500 K were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec and at temperatures between 300 and 500 K.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Polymer Engineering and Science; 14; Apr. 197
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  • 23
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    Shock shapes of blunt bodies in hypersonic helium, air, and CO2 flows (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A primary factor governing hypersonic flowfield characteristics of blunt vehicles entering planetary atmospheres is the normal shock density ratio. Hence, a means of duplicating or simulating the high density ratios experienced during planetary entry is needed. One facility having the capability of generating a range of hypersonic-hypervelocity flow conditions in arbitrary test gases is the expansion tube. Preliminary shock shape results obtained in the Langley 6-in. expansion tube at hypersonic conditions are presented. Normal shock density ratios from approximately 4 to 19 were generated using helium, air, and CO2 test gases at freestream velocities from 5 to 7 km/sec. Test models were a flat-faced cylinder and the Viking aeroshell.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Mar. 197
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  • 24
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    Computation of transonic flow about lifting wing-cylinder combinations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Some results are described for a lifting rectangular wing centrally located on a circular-cylindrical body. This simple configuration has been utilized in order to assess the merits of a mapping technique for wing-body configurations. The procedure employed makes use of a coordinate transformation to simplify specification of the surface boundary condition in the computation of the flow about the wing. The method can be extended to incorporate wing sweep, finite length body of noncircular cross section, and arbitrary wing placement; however, these extensions involve a considerable increase in complexity of the problem.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Apr. 197
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  • 25
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    Solid state and fusion resistance spot welding of TD-NiCr sheet (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 26
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    A vortex entrainment model applied to slender delta wings (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A mathematical model of the vortex flow over a slender sharp-edged delta wing is proposed, and is shown to provide good agreement with the experiment. Although the technique requires experimental data in the form of the vortex core locations, it does account for the previously ignored mass entrainment of the vortex core.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Jan. 197
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  • 27
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    Extraction of derivatives from flight data for several aircraft, using the LRC interactive computer system (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Results are presented of a procedure for estimating stability and control parameters from flight data, by using maximum likelihood methods employing an interactive computer system, which was established at the NASA Langley Research Center. Problems encountered are discussed.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 49-76
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  • 28
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    Identification of aircraft stability and control derivatives in the presence of turbulence (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A maximum likelihood estimator for a linear system with state and observation noise is developed to determine stability and control derivatives from flight data obtained in the presence of turbulence. The formulation for the longitudinal short-period mode is presented briefly, including a special case that greatly simplifies the problem if the measurement noise on one signal is negligible. The effectiveness and accuracy of the technique are assessed by applying it first to simulated flight data, in which the true parameter values and state noise are known, then to actual flight data obtained in turbulence. The results are compared with data obtained in smooth air and with wind-tunnel data. The complete maximum likelihood estimator, which accounts for both state and observation noise, is shown to give the most accurate estimate of the stability and control derivatives from flight data obtained in turbulence. It is superior to the techniques that ignores state noise and to the simplified method that neglects the measurement noise on the angle-of-attack signal.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 77-114
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  • 29
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    A comparison of two methods of extracting stability derivatives from flight test data (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Two methods for extracting stability derivatives from flight data are compared. A modified Newton-Raphson quasilinearization minimization technique and a digital-analog (hybrid) matching technique were used to analyze the same data maneuvers obtained from two aircraft. About 70 maneuvers from an F-111E aircraft were analyzed over a Mach number range of 0.3 to 2.0 and an angle of attack range of 3 to 19 degrees. About 20 maneuvers were analyzed for the X-24A lifting body at Mach numbers of 0.5, 0.8, and 0.9, and an angle of attack range of 4 to 13 degrees. Stability derivatives were extracted from these maneuvers and the results from the two techniques, along with wind tunnel results, were compared.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 43-48
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  • 30
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    Ultrasonic examination of welded joints of great thickness in mechanical equipment under pressure (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The requirements involved in choosing ultrasonic devices, the factors that affect testing, and recommended calibration methods are discussed. The ultrasonic testing method is the only method that up to now permits detection of defects in welded joints of great thickness. The results are conditioned by the performances of the devices employed as well as by the degree of instruction of the personnel.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 199-203
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  • 31
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    Influence of ultrasounds on electrolytic polishing (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: On the basis of study of the electrolytic polishing of metal pieces, the following conclusions can be drawn: (1) Utilization of ultrasonically irradiated electrolytes in the electrolytic polishing of copper and steel pieces leads to enhanced polishing quality. (2) Polishing time for the reference pieces was twice as long as for the test pieces. (3) The chemical attack exerted on the surface of the test pieces in order to get the structure of the respective metal lasted less than half as long and yielded superior qualitative results in the copper as well as in the OT 60-2 steel test pieces polished with ultrasonically irradiated electrolytes. (4) The utilization of higher polishing current densities can be explained by the fact that the cavitational effect that arises in the electrolyte owing to ultrasounds contributes to an increase in the solution's electrical conductivity and elimination of gases from the electrolyte.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 210-214
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  • 32
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    Correlation for estimating vortex rotational velocity downstream dependence (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Description of a correlation, derived from water tank measurements in the wake of wings towed under water, that makes it possible to predict the downstream distance behind an aircraft in flight where its trailing vortex will begin to decay. Comparisons of measured and predicted data are discussed.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 33
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    Roll-up of aircraft trailing vortices using artificial viscosity (1974)
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    Publication Date: 2011-08-16
    Description: The artificial viscosity method of Kuwahara and Takami (1973) is used to calculate the roll-up of trailing vortices behind a number of practical aerodynamic configurations. Where possible, the results are compared for core location with available experimental data.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 34
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    Influence of ablation impurities on blunt body re-entry ionization (1974)
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    Publication Date: 2011-08-16
    Description: Electron density profiles which include the effect of an ablated sodium impurity were computed for the boundary layer on a blunt-nosed body re-entering the atmosphere at 7.62 km/sec. Profiles are computed from the nose to a distance of four diameters along the RAM C-payload. A finite-difference, laminar, nonequilibrium chemistry boundary-layer program was used. Comparison of theory with S-band diagnostic antenna results, electron concentration deduced from X- and C-band attenuation data, and Langmuir probe data at several different aft body locations show that agreement is good at high altitude. At the lower altitudes there is disagreement between theory and S-band antenna data where the apparent discrepancy is attributed to the three-body recombination rate constant used for deionization of sodium coupled with the effect of angle of attack.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; June 197
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    Monitoring the presence of foreign bodies in the equipment (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The methods for monitoring the presence of foreign bodies in radio electronic equipment are discussed. Descriptions of the structural design under the operating principle of the device for detecting foreign bodies weighing to 0.0026 grams are given.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 100-102
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  • 36
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    Process for manufacturing slit collimators (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Peculiarities are described of the manufacturing process and the control of elements of slit collimators, the structural design of the required equipment and the process or assembling the collimators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 89-91
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  • 37
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    Method of applying a mirror reflecting layer to instrument parts (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A method follows for applying a mirror reflecting layer to the surfaces of parts, instruments, apparatus, and so on. A brief analysis is presented of the existing methods of obtaining the mirror surface and the advantages of the new method of obtaining the mirror surface by polymer casting mold are indicated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 84-88
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  • 38
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    Process of manufacturing small-module gears with internal coupling (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The small module geared coupling of an undulatory transmission is considered. Versions of the manufacture of gears with internal coupling and the instruments and equipment used, are reported.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 77-79
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  • 39
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    Process of manufacturing grids from wire less than 0.025 MM in diameter by the galvanic growth method (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The process of manufacturing grids, the peculiarities of the structural design, the fittings, the requirements on the tools and work area are discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 80-83
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  • 40
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    Prospective areas in the production technology of scientific equipment for space research (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The average labor of individual types of operations in the percentage ratio of the total labor consumption of manufacturing scientific instruments and apparatus for space research is presented. The prospective areas in the production technology of billet, machining, mechanical assembly, installation and assembly, adjustment and regulation and testing and control operations are noted. Basic recommendations are made with respect to further reduction of labor consumption and an increase in the productivity of labor when manufacturing scientific equipment for space research.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 69-76
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  • 41
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    Servosystem with an undulatory reducing gear (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The development of a potentiometric servosystem is described that has a dc microservomotor, which is the built in drive of an undulatory reducing gear. The operation of the system and the structural design of the undulatory reducing gear are elaborated. Results are presented from analyzing some tests of various types of undulatory reducing gear generators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 44-53
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  • 42
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    Effectiveness of solid lubricant coatings for friction in hard vacuum (10-9 tor) (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 99-112
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  • 43
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    Influence of low temperatures of friction and wear (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A brief review of studies on low-temperature friction are briefly reviewed. A facility and technique for studying friction both in air and in vacuum at temperatures of +20 and -190 C is described. Results of a wear study of structural steels operating together with chromium steel are presented. It is shown that reduction of the test temperature in vacuum leads in certain cases to marked increase of the wear magnitude and friction coefficient. This is associated not only with the general change of the mechanical properties of the materials but also with the influence of temperature reduction on the hardening and structural formation taking place in the surface layers during friction.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 65-75
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  • 44
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    Study of the possibility of using solar radiant energy for welding and brazing metals (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The solar spectrum at the surface of the earth is analyzed. A facility for creating concentrated solar radiant energy flux is described, and data on its energetic capabilities are presented. The technology of solar welding by the fusion technique and joining by high-temperature brazing is examined. The use of concentrated solar radiant energy for welding and brazing metals and alloys is shown. The results of mechanical tests and microscopic and macroscopic studies are presented.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 9-18
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  • 45
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    Asperity lubrication and cavitation in face seals (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The basic aspect of parallel-surface lubrication that distinguishes it from other areas of lubrication technology is that classical lubrication theory does not predict the existence of a stable hydrodynamic film for steady-state, isothermal, incompressible flow between smooth, parallel surfaces. Hydrodynamic films between apparently parallel surfaces have been observed in practice and are often essential for the reliable performance of thrust bearings and seals. In order to account for this fortunate discrepancy between classical theory and experiment, load-support mechanisms relating to accidential features characteristic of seal performance, which relax one or more of the assumptions in the classical theory and permit the theoretical prediction of load support are proposed. Some of the features that have been analyzed are vibratory effects such as wobble and bounce, surface waviness, nonsymmetric rotation resulting from various types of misalignment, lubricant density change, non-Newtonian lubricant effects, and surface roughness.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NBS The Role of Cavitation in Mech. Failures; p 77-87
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  • 46
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    Some after-dinner reflections on system identification (1974)
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    Publication Date: 2011-08-16
    Description: The growth of the field of system identification is discussed along with changes in methodology which have taken place in recent years. The similarity between pattern recognition and system identification is pointed out, involving the modelling in the latter and the feature selection problem in the former. It is stated that once a model is formulated, including the disturbances and measurement errors, the parameter finding can be formulated as a statistical estimation problem. The various techniques and their application are discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 381-385
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  • 47
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    Systems identification - reprise and projections (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A state-of-the-arts review is given for the field of system identification. Progress in the field is traced from the early models of dynamic systems by Sir Isaac Newton up to the present day use of advanced techniques for numerous applications.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 375-379
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  • 48
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    A new criterion for modeling systems (1974)
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    Publication Date: 2011-08-16
    Description: The criterion that is proposed is an expected value of the mean square response error as an alternative to testing a model against new data. Modeling with respect to this new criterion does not change the estimate for a given model format from a maximum likelihood estimate or mean square response error estimate. The new criterion does, however, provide a means of comparing models with different formats and varying complexity. A numerical example is used to illustrate the application of the proposed criteria and the problem of searching for the best model. For all but the most trivial system identification problems, it is shown that a prohibitive number of combinations of terms of the model must be investigated to ensure the final model is best.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 291-313
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  • 49
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    Effects of flight instrumentation errors on the estimation of aircraft stability and control derivatives (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An error analysis program based on an output error estimation method was used to evaluate the effects of sensor and instrumentation errors on the estimation of aircraft stability and control derivatives. A Monte Carlo analysis was performed using simulated flight data for a high performance military aircraft, a large commercial transport, and a small general aviation aircraft for typical cruise flight conditions. The effects of varying the input sequence and combinations of the sensor and instrumentation errors were investigated. The results indicate that both the parameter accuracy and the corresponding measurement trajectory fit error can be significantly affected. Of the error sources considered, instrumentation lags and control measurement errors were found to be most significant.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 261-280
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  • 50
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    Nonlinear parameter identification: Ballistic range experience applicable to flight testing (1974)
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    Publication Date: 2011-08-16
    Description: The parameter identification scheme being used is a differential correction least squares procedure (Gauss-Newton method). The position, orientation, and derivatives of these quantities with respect to the parameters of interest (i.e., sensitivity coefficients) are determined by digital integration of the equations of motion and the parametric differential equations. The application of this technique to three vastly different sets of data is used to illustrate the versatility of the method and to indicate some of the problems that still remain.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 191-195
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  • 51
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    On particle motion in an electric welding arc treated with sonic or ultrasonic oscillations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The criteria for the stability of the subharmonic, harmonic, or superharmonic oscillations determine the relation between acoustic field parameters and particle parameters. The derived formulas underlie the destruction of the fragile Widmanstatten structure in weldings and therefore the designing of the generators that must be used for this welding process.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 131-138
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  • 52
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    Cracking and reformation of saturated hydrocarbons by ultrasound in the presence of water (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The exposure of saturated hydrocarbons to ultrasound (800 kHz, 6 W/sq cm) in the presence of water results in: (1) cleavage of the carbon chain, producing saturated and unsaturated hydrocarbons with a lower number of carbons than the initial hydrocarbon (cracking); and (2) recombination after cleavage, producing saturated and unsaturated hydrocarbons with a higher number of carbons than the initial hydrocarbon (reformation). The addition of argon facilitates these phenomena. The effects are attributed to a homolytic (radical) mechanism occurring within the cavitation bubbles under the effects of microsparks.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 139-147
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  • 53
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    Contributions to the use of macrosounds for boiler decrusting (1974)
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    Publication Date: 2011-08-16
    Description: The results of an investigation indicate the following: (1) The deposition of incrustations on the heating surfaces of steam boilers can be prevented by inserting between heating surface and water an insulating layer on which the boiler incrustation will be deposited. (2) The insulating layer reduces the coefficient of heat transmission by 2%. (3) The insulating layer can be removed by macrosounds with a frequency of about 20 kHz, after any interval of boiler operation.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 126-130
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  • 54
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    Contributions to study of the stability of the electric welding arc under the action of acoustic pressure (1974)
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    Publication Date: 2011-08-16
    Description: During the treatment of an electric welding arc with ultrasonic oscillations, an improvement was found in overall source-arc stability. Theoretical explanations are provided for this phenomenon and formulas of equivalence between the classical arc and the treated arc are derived, taking stability as their criterion. A knowledge of this phenomenon can be useful in extending the applications of ultrasounds to different forms of electric arcs.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 118-125
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  • 55
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    Aerodynamics of jet flap and rotating cylinder flap STOL concepts (1974)
    In:  CASI
    Details
    Publication Date: 2012-05-22
    Description: The aerodynamic effectiveness of various propulsive lift concepts to provide for the low speed performance and control required for short takeoff and landing aircraft is discussed. The importance of the interrelationship between the propulsion system and aerodynamic components of the aircraft is stressed. The relative effectiveness of different lift concepts was evaluated through static and wind tunnel tests of various aerodynamic models and propulsion components, simulations of aircraft, and in some cases, flight testing of research aircraft incorporating the concepts under study. Results of large scale tests of lift augmentation devices are presented. The results of flight tests of STOL research aircraft with augmented jet flaps and rotating cylinder flaps are presented to show the steeper approach flight paths at low forward speeds.
    Keywords: AERODYNAMICS
    Type: AGARD V/STOL Aerodyn.; 6 p
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  • 56
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    Acoustical levitation for space processing (1974)
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    Publication Date: 2011-08-16
    Description: It is pointed out that many space-manufacturing processes will require the manipulation of weightless molten material within a container in such a way that the material does not touch the container wall. A description is given of an acoustical method which can be used for the positioning and shaping of any molten material including nonconductors such as glasses. The new approach makes use of an acoustical standing wave which is excited within an enclosure or resonator.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Astronautics and Aeronautics; 12; July-Aug
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  • 57
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    A generalized-capacity-matrix technique for computing aerodynamic flows (1974)
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    Publication Date: 2011-08-16
    Description: A numerical generalized-capacity-matrix technique is developed for application to aerodynamic flow computations. This technique allows the very fast direct (noniterative) numerical elliptic solvers to be used in problems with arbitrary internal boundaries and with a wide class of boundary conditions, including numerical application of the Kutta condition on an airfoil without iteration. Accuracy, speed, and usefulness of the technique are demonstrated with linear problems for potential flows over airfoil shapes. The method's main advantages, however, can be exploited within iterative procedures for a variety of complex flow problems governed by systems of equations not necessarily elliptic or linear.
    Keywords: AERODYNAMICS
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  • 58
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    Auger analysis of films formed on metals in sliding contact with halogenated polymers (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The use of Auger electron spectroscopy (AES) to search for transferred polymer must contend with the fact that there has been no published work on Auger analysis of polymers. Since this is a new area for AES, the Auger spectra of polymers and of halogenated polymers in particular is discussed. It is shown that the Auger spectra of halogenated polymers have certain characteristics that permit an assessment of whether a polymeric transfer film has been established by sliding contact. The discussion is general and the concepts should be useful in considering the Auger analysis of any polymer. The polymers chosen for this study are the halogenated polymers polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polychlorotrifluorethylene (PCTFE).
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Applied Physics; 45; July 197
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  • 59
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    Fast direct numerical solution of the nonhomogeneous Cauchy-Riemann equations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A fast direct (noniterative) 'Cauchy-Riemann Solver' is developed for solving the finite-difference equations representing systems of first-order elliptic partial differential equations in the form of the nonhomogeneous Cauchy-Riemann equations. The method is second-order accurate and requires approximately the same computer time as a fast cyclic-reduction Poisson solver. The accuracy and efficiency of the direct solver are demonstrated in an application to solving an example problem in aerodynamics: subsonic inviscid flow over a biconvex airfoil. The analytical small-perturbation solution contains singularities, which are captured well by the computational technique. The algorithm is expected to be useful in nonlinear subsonic and transonic aerodynamics.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; May 1974
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  • 60
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    Estimation of longitudinal aerodynamic coefficients and comparison with wind-tunnel values (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Some recent experience at Ames Research Center in the estimation of aerodynamic coefficients for the Lear-Jet and the Augmentor Wing Jet STOL Research Aircraft is reviewed. The coefficients estimated from flight data are compared with values based on large-scale wind-tunnel tests. The results obtained by the regression and quasilinearization identification techniques are also compared. The regression method generally provides the lower standard deviation in the coefficient estimates and provides the better fit to the wind-tunnel values. The addition of nonlinear terms in the aerodynamic equations decreases the difference between the estimated and measured time histories but also increases the standard deviation in the estimated coefficient values.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 125-148
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  • 61
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    Research on wood bending in a macrosonic field (1974)
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    Publication Date: 2011-08-16
    Description: Woodworking often requires the wood to be bent into different shapes. In view of the fact that macrosonic waves compress and expand the medium through which they are being propagated we assumed that wood subjected to the action of these waves during the bending process would have enhanced plasticity as a result of the loosening-up that takes place in it, as well as of the reduction in effort. To this effect, the bending of wood plasticized in a macrosonic field was studied. This bending took place under good conditions, and structural analyses conducted with the aid of an electron microscope proved initial premises to be corrent. Applied on an industrial scale, this procedure would contribute to improving the technology of wood bending as well as to eliminating factory spoilage.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 234-237
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  • 62
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    Some aspects of using ultrasounds to improve sulfurous mineral flotation technology (1974)
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    Publication Date: 2011-08-16
    Description: The results are discussed which were obtained with a new method of desorption of collector reagents connected with improving the selectivity of the flotation of copper and lead concentrate through the action of ultrasounds. Analysis of the results obtained by treating copper and lead concentrate in an ultraacoustic field indicates an increase in the copper content of the copper concentrate, of the lead content in the lead concentrate and, at the same time, a reduction in the lead of the copper concentrate.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 112-117
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  • 63
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    On the dynamic stability of the focus of deformation in the cold drawing of tubes on an ultrasonically activated plug (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: In the case of macrosonic drawing, it was experimentally determined that tube eccentricity is less than in the case of tube drawing without macrosonics. On this basis, a theoretical analysis was carried out of the effect of macrosounds on tube eccentricity, an analysis that qualitatively confirms the experimental data.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-15663); p 102-111
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  • 64
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    Some research concerning the cold drawing of tubes on an ultrasonically activated plug (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The results are discussed of studies of the influence of macrosounds on a metal's friction and deformation conditions at the focus of deformation, on the mechanical characteristics of cold-drawn tubes, and on the dynamic stability of the focus of deformation. In the course of these studies, experimental equipment was developed and perfected. Under the proposed conditions the cold drawing of tubes on an ultrasonically activated plug turned out to be viable and efficient.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 89-96
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  • 65
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    Powder pressing in a macrosonic field (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An investigation was conducted to extend the technology of powder product manufacturing to new forms and sizes, to improve their quality as well as pressing efficiency and to reduce waste. In the course of metal and nonmetal powder briquette pressing, macrosounds were associated with the external static pressing force, which led to an increase in the relative height, density and physicomechanical characteristics of the briquettes. This method permits the extension of the range of products that can be manufactured from powders and the improvement of their quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 77-83
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  • 66
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    Metalworking with ultrasonic energy (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The application of ultrasonic radiation for metal working of steel is discussed. It is stated that the productivity of the ultrasonic working is affected by the hardness of the material to be worked, the oscillation amplitude, the abrasive temperature, and the grain size. The factors that contribute to an increase in the dislocation speed are analyzed. Experimental data are provided to substantiate the theoretical parameters.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 60-66
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  • 67
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    Contributions to the study of ultrasonic machining (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Problems in the industrial application of ultrasounds are discussed. Starting from the industrial characteristics of ultrasonic working, especially of hard and fragile materials that are difficult to work by means of conventional methods, the characteristics of the feed system, the circulation system of the abrasive suspension, and the ultra-acoustic unit of machines for ultrasonic working are described. Experiments on the behavior of different types of ultra-acoustic unit design and on the optimal operating conditions connected with the manner of execution, fixation, and excitation conditions are analyzed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 53-59
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  • 68
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    Vortex-induced heating to cone flaps at Mach 6 (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Discussion of the local heating effect on the lee-side control flaps of supersonic configurations due to the interaction between vortices and leeward control surfaces at an angle of attack. Considerations are given for an appropriate positioning of control flaps to alleviate such interactions and the resulting thermal effect. Tests are carried out on a sharp right circular cone with two types of flap configurations in a study of oil flow patterns about the cone at selected angles of attack. Splitting of flaps and moving them to positions away from the symmetry plane did reduce the heating but also reduced the average flap pressure and increased flow complexity.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Mar. 197
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  • 69
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    An improved static probe design (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A new static probe design is described in which the static holes are located much closer to the tip than in conventional probes. The new probe shows promise for use in some situations where conventional probes become highly inaccurate. An additional advantage of the new design is that, when used in static pressure survey rakes, the probes can be located much closer together than in conventional designs and still ensure that disturbances from neighboring probe tips do not affect the static readings.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Apr. 197
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  • 70
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    Vortex-induced heating to a cone-cylinder body at Mach 6 (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Presented data on vortex-induced heating in a cone-cylinder body at Mach 6 show that the most severe heating need not occur as a result of the interaction of the primary vortices with the lee surface, even though this interaction produces a large, well-defined featherline oil smear. It is pointed out that the severity of vortex-induced heating is extremely sensitive to Reynolds number and geometry and that there exists a 'threshold Reynolds number' below which vortex-induced heating decreases abruptly.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Feb. 197
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  • 71
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    Simulation of real-gas effects for Mars entry (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The changes in aerodynamic characteristics due to real-gas effects associated with high speed flight (characterized by large shock density ratios) are primarily the result of changes in surface pressures acting on the forebody. The surface pressures are affected by a change in shock density ratio (real-gas effects) in two ways. First, the level of pressure at the stagnation point relative to freestream dynamic pressure is changed, and second, the distribution of surface pressure relative to stagnation-point pressure is changed. The density-ratio effect on the stagnation point pressure level can be estimated by considering the flow of a perfect gas about a blunt body.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 11; Jan. 197
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  • 72
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    V/STOL aerodynamics: A review of the technology (1974)
    In:  CASI
    Details
    Publication Date: 2012-05-22
    Description: An analysis of the development and technological applications of V/STOL aircraft is presented. The use of V/STOL aircraft to overcome the limitations of conventional aircraft is discussed. The aspects of V/STOL aircraft which are considered are: (1) economic penalties of propulsive lift, (2) advantages of propulsive lift, (3) potential improvements in V/STOL aircraft, (4) the aerodynamics of V/STOL aircraft, and (5) proposals for additional research in V/STOL development.
    Keywords: AERODYNAMICS
    Type: AGARD V/STOL Aerodyn.; 13 p
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  • 73
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    A general purpose stabilised balloon platform (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The development of a three axis stabilized balloon platform capable of being operated in three modes of increasing accuracy is discussed. The system relies on angular motion sensing for primary feedback with linear accelerometers, magnetometers, and a star sensor for positional information. When under primary control the system will acquire and stabilize on any accessible part of the celestial sphere. A video verification system is included to provide pointing confirmation. Under improved accuracy control, the star sensor is used to lock onto a target star.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 284-293
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  • 74
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    Air Force Cambridge Research Laboratories balloon operations (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The establishment and functions of the AFCRL balloon operations facility are discussed. The types of research work conducted by the facility are defined. The facilities which support the balloon programs are described. The free balloon and tethered balloon capabilities are analyzed.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 160-164
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  • 75
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    Balloon platform for extended-life astronomy research (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A configuration has been developed for a long-life balloon platform to carry pointing telescopes weighing as much as 80 pounds (36 kg) to point at selected celestial targets. A platform of this configuration weighs about 375 pounds (170 kg) gross and can be suspended from a high altitude super pressure balloon for a lifetime of several months. The balloon platform contains a solar array and storage batteries for electrical power, up and down link communications equipment, and navigational and attitude control systems for orienting the scientific instrument. A biaxial controller maintains the telescope attitude in response to look-angle data stored in an on-board computer memory which is updated periodically by ground command. Gimbal angles are computed by using location data derived by an on-board navigational receiver.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 136-144
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  • 76
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    An orientable, stabilized balloon-borne gondola for around-the-world flights (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A system capable of pointing a balloon-borne telescope at selected celestial objects to an accuracy of approximately 10 arc minutes for an extended period (weeks to months) without reliance on telemetry is described. A unique combination of a sun/star tracker, an on-board computer, and a gyrocompass is utilized for navigation, source acquisition and tracking, and data compression and recording. The possibilities for intelligent activities by the computer are also discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Telescope Systems for Balloon-Borne Res.; p 71-80
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  • 77
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    Experimental and analytical studies in tilt-rotor aeroelasticity (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An overview of an experimental and analytical research program underway for studying the aeroelastic and dynamic characteristics of tilt-rotor VTOL aircraft is presented. Selected results from several investigations of scaled models in the transonic dynamics tunnel, as well as some results from a test of a flight-worthy proprotor in the full-scale wind tunnel are shown and discussed with a view toward delineating various aspects of dynamic behavior peculiar to proprotor aircraft. Included are such items as proprotor/pylon stability, whirl flutter, gust response, and blade flapping. Theoretical predictions are shown to be in agreement with the measured stability and response behavior.
    Keywords: AERODYNAMICS
    Type: Its Rotorcraft Dyn.; p 171-184
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  • 78
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    Theory and comparison with tests of two full-scale proprotors (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A nine degrees-of-freedom theoretical model was developed for investigations of the dynamics of a proprotor operating in high inflow axial flight on a cantilever wing. The theory is described, and the results of the analysis are presented for two proprotor configurations: a gimballed, stiff-inplane rotor, and a hingeless, soft-inplane rotor. The influence of various elements of the theory are discussed, including the modeling used for the blade and wing aerodynamics, and the influence of the rotor lag degree of freedom. The results from full-scale tests of the two proprotors are presented and compared with the theoretical results.
    Keywords: AERODYNAMICS
    Type: Its Rotorcraft Dyn.; p 159-169
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  • 79
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    Effect of gravity on liquid phase sintering (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The unique conditions offered by the earth orbital environment in material processing involving both solid and liquid phases, such as liquid phase sintering, were studied. An experimental development program involving both test and theoretical work was initiated. Experimental work using material combinations selected such that maximum information about the effect of gravity can be derived has been conducted. Wetting of the solid phase by the liquid during sintering is an important phenomenon in liquid phase sintering, and gravity has influence on both capillary phenomenon and density segregation; hence, material combinations were selected such that these two effects can be suitably studies. The experimental work is meant to form the basis for similar comparative work done under low-g conditions. The part of the model dealing with the capillary phenomenon, as related to liquid phase sintering and the effect of gravity on it, suggest that gravity will have negligible effect on the Bond number and that the cohesive force is dependent on both the amount of liquid phase and the angle of contact.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 963-1001
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  • 80
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    Acoustic field positioning for containerless processing (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The non-contact positioning of materials in a space processing chamber is accomplished using a new type of acoustic levitator. Liquid and solid materials are positioned using a single source of sound. Fine control of position may be obtained by motion of an acoustical reflector. Electrical power required is usually less than 100 watts. The system operates satisfactorily at high and low temperatures and is adaptable as an add-on feature to existing space experiments. Containerless melting and solidification can be performed and a freely suspended liquid can be shaped to the contour of the sound field. Experiments are described in which aluminum, glass and plastic materials are melted and solidified in the containerless state. The system has applications to containerless crystal growth, melting and related processes.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 647-677
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  • 81
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    Acoustical positioning chamber for space processing (1974)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: By readily levitating, positioning, and manipulating materials placed in it, the acoustical resonator can serve a variety of space processing operations, such as drawing crystals, degassing, and stirring of melts, and casting.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 679-690
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  • 82
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    System design considerations for free-fall materials processing (1974)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: The design constraints for orbiting materials processing systems are dominated by the limitations of the flight vehicle/crew and not by the processes themselves. Although weight, size and power consumption are all factors in the design of normal laboratory equipment, their importance is increased orders of magnitude when the equipment must be used in an orbital facility. As a result, equipment intended for space flight may have little resemblance to normal laboratory apparatus although the function to be performed may be identical. The same considerations influence the design of the experiment itself. The processing requirements must be carefully understood in terms of basic physical parameters rather than defined in terms of equipment operation. Preliminary experiments and analysis are much more vital to the design of a space experiment than they are on earth where iterative development is relatively easy. Examples of these various considerations are illustrated with examples from the M518 and MA-010 systems. While these are specific systems, the conclusions apply to the design of flight materials processing systems both present and future.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 595-601
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  • 83
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    Comparison of the experimental aerodynamic characteristics of theoretically and experimentally designed supercritical airfoils (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A lifting airfoil theoretically designed for shockless supercritical flow utilizing a complex hodograph method has been evaluated in the Langley 8-foot transonic pressure tunnel at design and off-design conditions. The experimental results are presented and compared with those of an experimentally designed supercritical airfoil which were obtained in the same tunnel.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3082 , L-9548 , NAS 1.15:X-3082
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  • 84
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    A study of the nonlinear aerodynamics of bodies in nonplanar motion (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Concepts from the theory of functionals are used to develop nonlinear formulations of the aerodynamic force and moment systems acting on bodies in large-amplitude, arbitrary motions. The analysis, which proceeds formally once the functional dependence of the aerodynamic reactions upon the motion variables is established, ensures the inclusion, within the resulting formulation, of pertinent aerodynamic terms that normally are excluded in the classical treatment. Applied to the large-amplitude, slowly varying, nonplanar motion of a body, the formulation suggests that the aerodynamic moment can be compounded of the moments acting on the body in four basic motions: steady angle of attack, pitch oscillations, either roll or yaw oscillations, and coning motion. Coning, where the nose of the body describes a circle around the velocity vector, characterizes the nonplanar nature of the general motion.
    Keywords: AERODYNAMICS
    Type: NASA-TR-R-421 , A-5057
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  • 85
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    Simple methods for determining the virtual origin of turbulent boundary layers in hypersonic flow on sharp-edged flat plates (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Two methods for determining the virtual origin of turbulent boundary layers in hypersonic flow are evaluated. The results of the analyses are restricted to wind-tunnel models having sharp-edged surfaces with zero or small pressure gradients. Virtual origin and skin friction estimates from these two methods are compared with values from a base method for which the virtual origin is calculated from the measured momentum thickness at a station downstream of boundary layer transition.
    Keywords: AERODYNAMICS
    Type: ASME PAPER 74-APM-V
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  • 86
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    Forward slanted slot throat stability bypass to increase the stable airflow range of a Mach 2.5 inlet with 60 percent internal contraction (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The results of an experimental investigation to increase the stable airflow operating range of a supersonic mixed-compression inlet are presented. Two forward-slanted slot stability-bypass entrance configurations were tested. In terms of diffuser-exit corrected airflow, a large inlet stable airflow range of 18.5 percent was obtained with the superior configuration if a constant pressure was maintained in the bypass plenum. Limited unstart angle-of-attack data are presented.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-2973 , E-7706
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  • 87
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    Effect of screen-induced total-pressure distortion on axial-flow compressor stability (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental investigation was made to determine the effects of screen-induced total-pressure distortions on two J85-GE-13 turbojet engines. Results were compared to those from a previous program run with a third engine. All compressors were found to be sensitive to a critical angle of circumferential distortion equal to 60 deg., and they all adhered closely to the parallel compressor model. The sensitivity of compressor exit pressure to virtually any type of distortion pattern can be determined by defining stall lines for undistorted, hub radial distorted, and tip radial distorted inflows. The effect of multiple sectors of circumferential distortion is defined.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3017 , E-7792
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  • 88
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    Combined Quadrupole-dipole Model for Inlet Flow Distortion Noise from a Subsonic Fan (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A combined quadrupole-dipole model has been developed for the noise generated by inlet flow distortion in a subsonic fan. A formula is derived for the total upstream-radiated acoustic power in each tone as a function of the design parameters of the fan and the properties of the inlet flow distortion. Numerical results are obtained for values of the parameters corresponding to various quiet fans. The analysis is compared with noise measurements taken on a 51-cm (20-in.) diameter research fan as well as with those taken on a number of full-scale fan stages. Fairly good agreement was obtained. It should therefore be possible to use this model to study the noise-reduction potential of the various fan design parameters.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7676 , E-7881
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  • 89
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    Low speed aerodynamic characteristics of NACA 6716 and NACA 4416 airfoils with 35 percent-chord single-slotted flaps (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An investigation was conducted in a low-turbulence pressure tunnel to determine the two-dimensional lift and pitching-moment characteristics of an NACA 6716 and an NACA 4416 airfoil with 35-percent-chord single-slotted flaps. Both models were tested with flaps deflected from 0 deg to 45 deg, at angles of attack from minus 6 deg to several degrees past stall, at Reynolds numbers from 3.0 million to 13.8 million, and primarily at a Mach number of 0.23. Tests were also made to determine the effect of several slot entry shapes on performance.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-2623 , L-8410
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  • 90
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    Flight Reynolds number effects on a contoured boattail nozzle at subsonic speeds (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A contoured boattail nozzle typical of those used on a twin-engine fighter was tested on an underwing nacelle mounted on an F-106B aircraft. The gas generator was a J85-GE-13 turbojet engine. The effects of Reynolds number, Mach number, and angle of attack on boattail drag and boattail pressure profiles were investigated. Increasing Reynolds number caused a slight reduction in boattail drag at both Mach 0.7 and 0.9. The nozzle had relatively low boattail drag even though the flow was separated over a large portion of the boattail.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3053 , E-7818
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  • 91
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    An Analytical Investigation of Wing-Jet Interaction (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The aerodynamic interaction between the wing and an inviscid jet with Mach number nonuniformity is formulated by using a two-vortex-sheet model for the jet. One of the vortex sheets accounts for the induced jet flow and the other the induced outer flow. No additional source distribution is needed for the jet at an angle of attack. The above problem is solved by satisfying the jet and wing tangency and the jet pressure-continuity conditions and using a quasi vortex lattice method for computing the induced flow field. The latter method is derived through theoretical consideration by properly accounting for singularities present in the equations and possesses the same simplicity and generality as the conventional vortex lattice method but has a better rate of numerical convergence. The resulting system of algebraic equations is solved by Purcell's vector method. The numerical formulation is first applied to the wing-slipstream interaction problem. Results for one centered-jet configuration are compared with those predicted by some existing theories.
    Keywords: AERODYNAMICS
    Type: NASA-CR-138140 , CRINC-FRL-74-001
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  • 92
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    Flutter suppression and gust alleviation using active controls (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The effects of active controls on the suppression of flutter and gust alleviation of two different types of subsonic aircraft (the Arava, twin turboprop STOL transport, and the Westwind twin-jet business transport) are investigated. The active controls are introduced in pairs which include, in any chosen wing strip, a leading-edge (LE) control and a trailing-edge (TE) control. Each control surface is allowed to be driven by a combined linear-rotational sensor system, located on the activated strip. The control law, which translates the sensor signals into control surface rotations, is based on the concept of aerodynamic energy. The results indicate the extreme effectiveness of the active systems in controlling flutter. A single system spanning 10% of the wing semispan made the Arava flutter-free, and a similar active system, for the Westwind aircraft, yielded a reduction of 75% in the maximum bending moment of the wing and a reduction of 90% in the acceleration of the cg of the aircraft. Results for simultaneous activation of several LE - TE systems are presented. Further work needed to bring the investigation to completion is also discussed.
    Keywords: AERODYNAMICS
    Type: NASA-CR-138658 , TAE-198
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  • 93
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    The passage of an infinite swept airfoil through an oblique gust (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An approximate solution is reported for the unsteady aerodynamic response of an infinite swept wing encountering a vertical oblique gust in a compressible stream. The approximate expressions are of closed form and do not require excessive computer storage or computation time, and further, they are in good agreement with the results of exact theory. This analysis is used to predict the unsteady aerodynamic response of a helicopter rotor blade encountering the trailing vortex from a previous blade. Significant effects of three dimensionality and compressibility are evident in the results obtained. In addition, an approximate solution for the unsteady aerodynamic forces associated with the pitching or plunging motion of a two dimensional airfoil in a subsonic stream is presented. The mathematical form of this solution approaches the incompressible solution as the Mach number vanishes, the linear transonic solution as the Mach number approaches one, and the solution predicted by piston theory as the reduced frequency becomes large.
    Keywords: AERODYNAMICS
    Type: NASA-CR-2395
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  • 94
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    Wind tunnel blockage and support interference effects on winged-body models at Mach numbers from 0.6 to 1.0 (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Three sting-mounted winged-body models with tunnel blockages of 0.1, 1.0, and 2.0 percent were tested in the Lewis Research Center's 8- by 6- Foot Supersonic Wind Tunnel. Fuselage pressures were obtained over a Mach number range of 0.6 to 1.0 at angles of attack from 0 deg to 4 deg. Two other types of model support were investigated, which included simulated wing-tip and fuselage support-strut mountings. The effects of tunnel porosity and sidewall geometry were also investigated. Model blockage effects were small up to M sub 0 = 0.95. At higher speeds the major blockage effect observed was a displacement of the local transonic terminal shocks on the model. The effects of the wing-tip type of model support were small up to M sub 0 = 0.95, but disturbances were observed on the fuselage at higher speeds. Changes in local tunnel porosity were effective in reducing the disturbances up to M sub 0 = 0.975, but a change in sidewall geometry was not.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3011 , E-7596
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  • 95
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    An experimental study of the validity of the heat-field concept for sonic-boom alleviation (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental program was carried out in the NASA-Langley 4 ft x 4 ft supersonic pressure tunnel to investigate the validity of the heat-field concept for sonic boom alleviation. The concept involves heating the flow about a supersonic aircraft in such a manner as to obtain an increase in effective aircraft length and yield an effective aircraft shape that will result in a shock-free pressure signature on the ground. First, a basic body-of-revolution representing an SST configuration with its lift equivalence in volume was tested to provide a baseline pressure signature. Second, a model having a 5/2-power area distribution which, according to theory, should yield a linear pressure rise with no front shock wave was tested. Third, the concept of providing the 5/2-power area distribution by using an off-axis slender fin below the basic body was investigated. Then a substantial portion (approximately 40 percent) of the solid fin was replaced by a heat field generated by passing heated nitrogen through the rear of the fin.
    Keywords: AERODYNAMICS
    Type: NASA-CR-2381 , ATR-74(7218)-1
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  • 96
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    Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-2999 , E-7675
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  • 97
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    Estimation of deviation angle for axial-flow compressor blade sections using inviscid-flow solutions (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Development of a method of estimating deviation angles by analytical procedures was begun. Solutions for inviscid, irrotational flow in the blade-to-blade plane were obtained with a finite-difference calculation method. Deviation angles for a plane cascade with a rounded trailing edge were estimated by using the inviscid-flow solutions and three trailing-edge hypotheses. The estimated deviation angles were compared with existing experimental data over a range of incidence angles at inlet flow angles of 30 deg and 60 deg. The results indicate that deviation angles can be estimated accurately (within 1 deg) by using one of the three trailing-edge hypotheses, but only when pressure losses are low. A new trailing-edge hypotheses is presented which is suitable (for the cascade considered) for both low- and high-loss operating points.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7549 , E-7453
    Format: application/pdf
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  • 98
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    Normal loads program for aerodynamic lifting surface theory (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A description of and users manual are presented for a U.S.A. FORTRAN 4 computer program which evaluates spanwise and chordwise loading distributions, lift coefficient, pitching moment coefficient, and other stability derivatives for thin wings in linearized, steady, subsonic flow. The program is based on a kernel function method lifting surface theory and is applicable to a large class of planforms including asymmetrical ones and ones with mixed straight and curved edges.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-62326
    Format: application/pdf
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  • 99
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    Cold-air study of the effect on turbine stator blade aerodynamic performance of coolant ejection from various trailing-edge slot geometries. 1: Experimental results (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Trailing-edge slot configurations were investigated in a two-dimensional cascade of turbine stator blades. The trailing-edge slots were incorporated into blades with round trailing edges. The five blade configurations investigated included blades with two different trailing-edge thicknesses and four different slot widths. The results of the investigation showed that there was, in general, a significant increase in primary-air efficiency due to the coolant flow, the increase varying with slot configuration. For the five configurations tested, the average percent change in primary-air efficiency per percent coolant flow varied almost linearly from zero to about 1.4 percent over a range of coolant- to primary-air exit-velocity ratios between 0 and 1.2. However, for different configurations there was considerable deviation from the average values in the lower range of exit velocity ratios.
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-3000 , E-7743
    Format: application/pdf
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  • 100
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    A rapid numerical solution to subsonic flow over planar and axisymmetric profiles at an angle of attack of 0 deg (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A numerical solution is presented for the incompressible flow over thin planar and axisymmetric profiles at an angle of attack of 0 degrees. The method uses a finite-difference field solution to the governing equation with a Gauss-Seidel successive overrelaxation scheme. However, the use of a simple Cartesian grid system restricts this method to slender profiles. Results are presented for a cambered airfoil, airfoil in wall effect (two-dimensional flowthrough inlet), body of revolution, and flowthrough nacelle. A computer program is presented which can be used for any of the previously mentioned cases with simple input changes. Results for compressible flow are available with the use of the appropriate two-dimensional or axisymmetric compressibility corrections. Computational time for a typical field calculation of 3000 grid points and 200 cycles through the field is less than 1 minute with less than 50,000 octal storage on the Control Data Corporation 6600 computing system.
    Keywords: AERODYNAMICS
    Type: NASA-TN-D-7410 , L-8904
    Format: application/pdf
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