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At least 649 records · Page 36

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NASA NTRS1976

Improvements in search and rescue distress alerting and locating using satellites

This paper describes a system concept for search and rescue which is capable of making a major contribution to saving lives and reducing the search time for downed aircraft. In addition, a beacon location experiment is described using the Amateur Radio Satellite Corporation Oscar-6 and Oscar-7 spacecraft. The purpose of this experiment was to demonstrate the system concept above by determining the geographical location of a low power 'distress beacon' via satellite based on a single pass of Doppler frequency measurements. Preliminary results are presented showing beacon location recovery on the order of 10 km with indications that an order of magnitude improvement is entirely possible. This experiment is in support of NASA's current exploration into the role satellites might play in providing much needed improvements in the reliability, coverage and accuracy of present search and rescue procedures.

Brandel, D. L.↗

NASA NTRS1978

Improved thermal-tile barrier

Improved filler design, laser processing to seal ceramic fibers, and device for sliding barrier into tile gap improves thermal tile.

Cade, D. H.↗

NASA NTRS1978

Improved electron-beam welder

Report describes comprehensive test-and-evaluation program designed to improve performance of 7.5 kW electron-beam welder. Report describes prototype and seventeen changes incorporated to improve performance.

Smock, R. A.↗

NASA NTRS1978

Improvements in microelectrophoresis apparatus

Improvements to conventional microelectrophoresis techniques can simplify and standardize clinical diagnosis of large electrically charged molecules. Improvements include special trays, tray and cell covers, membranes, and temperature controls.

Grunbaum, B. W.↗

NASA NTRS1977

The benefits of improved technologies in agricultural aviation

The results are present for a study of the economic benefits attributed to a variety of potential technological improvements in agricultural aviation. Part 1 gives a general description of the ag-air industry and discusses the information used in the data base to estimate the potential benefits from technological improvements. Part 2 presents the benefit estimates and provides a quantitative basis for the estimates in each area study. Part 3 is a bibliography of references relating to this study.

Lietzke, K.↗

NASA NTRS1977

Improvement of maneuver aerodynamics by spanwise blowing

Spanwise blowing was used to test a generalized wind-tunnel model to investigate component concepts in order to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on performance, stability, and control at high angles of attack and subsonic speeds. Test data were obtained in the Langley high speed 7 by 10 foot tunnel at free stream Mach numbers up to 0.50 for a range of model angles of attack, jet momentum coefficients, and leading and trailing edge flap deflection angles. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack.

Erickson, G. E.↗

NASA NTRS1977

Research requirements to improve safety of civil helicopters

Helicopter and fixed-wing accident data were reviewed and major accident causal factors were established. The impact of accidents on insurance rates was examined and the differences in fixed-wing and helicopter accident costs discussed. The state of the art in civil helicopter safety was compared to military helicopters. Goals were established based on incorporation of known technology and achievable improvements that require development, as well as administrative-type changes such as the impact of improved operational planning, training, and human factors effects. Specific R and D recommendations are provided with an estimation of the payoffs, timing, and development costs.

Waters, K. T.↗

NASA NTRS1977

Economic consequences of improved temperature forecasts: An experiment with the Florida citrus growers (control group results)

A demonstration experiment is being planned to show that frost and freeze prediction improvements are possible utilizing timely Synchronous Meteorological Satellite temperature measurements and that this information can affect Florida citrus grower operations and decisions. An economic experiment was carried out which will monitor citrus growers' decisions, actions, costs and losses, and meteorological forecasts and actual weather events and will establish the economic benefits of improved temperature forecasts. A summary is given of the economic experiment, the results obtained to date, and the work which still remains to be done. Specifically, the experiment design is described in detail as are the developed data collection methodology and procedures, sampling plan, data reduction techniques, cost and loss models, establishment of frost severity measures, data obtained from citrus growers, National Weather Service, and Federal Crop Insurance Corp., resulting protection costs and crop losses for the control group sample, extrapolation of results of control group to the Florida citrus industry and the method for normalization of these results to a normal or average frost season so that results may be compared with anticipated similar results from test group measurements.

Source record↗

NASA NTRS1976

PMR polyimide prepreg with improved tack characteristics

Current PMR Polyimide prepreg technology utilizes methanol or ethanol solvents for preparation of the PMR prepreg solutions. The volatility of these solvents limits the tack and drape retention characteristics of unprotected prepreg exposed to ambient conditions. Studies conducted to achieve PMR 15 Polyimide prepreg with improved tack and drape characteristics were described. Improved tack and drape retention were obtained by incorporation of an additional monomer. The effects of various levels of the added monomer on the thermo-oxidative stability and mechanical properties of graphite fiber reinforced PMR 15 composites exposed and tested at 316 C (600 F) were discussed.

Serafini, T. T.↗

NASA NTRS1977

Experiments for improved positioning by means of integrated Doppler satellite observations and the NNSS broadcast ephemeris

An effort to improve station position recovery using broadcast ephemeris in Doppler data reduction was studied. A comparison of precise and broadcast ephemerides, treating the former as the standard, yielded information about the state disturbance that can be associated with the broadcast ephemeris. Statistical information about the state disturbance was used with current observational data for improved position recovery. The rank deficiency problem encountered in the short arc geodetic adjustment procedure was analysed and it was deduced that the fundamental rank deficiency is six, scale information being derivable from the wavelength of transmission. Coordinate differences between stations coobserving a pass are estimable. The uncertainty of the broadcast ephemeris, now in the WGS72 system, was assessed. It was conservatively estimated that its positional uncertainty may vary between 19 to 26 m in-track, 15 to 20 m cross-track and 9 to 10 m in radial directions depending on the incidence of the epoch of observations in the interinjection period.

Arur, M. G.↗

NASA NTRS1978

An Improved Version of the NASA-Lockheed Multielement Airfoil Analysis Computer Program

An improved version of the NASA-Lockheed computer program for the analysis of multielement airfoils is described. The predictions of the program are evaluated by comparison with recent experimental high lift data including lift, pitching moment, profile drag, and detailed distributions of surface pressures and boundary layer parameters. The results of the evaluation show that the contract objectives of improving program reliability and accuracy have been met.

Brune, G. W.↗

NASA NTRS1976

Application of powered-lift concepts for improved cruise efficiency of long-range aircraft

Results of studies conducted to explore the use of powered lift concepts for improved low speed performance of long range subsonic and supersonic cruise vehicles are summarized. It is indicated that powered lift can provide significant improvements in low speed performance, as well as substantial increases in cruise efficiency and range for both subsonic and supersonic cruise configurations.

Coe, P. L., Jr.↗

NASA NTRS1978

Study program for design improvements of the X-3060 and X-3075. Phase 1: Study definition

The existing designs of the X-3060 and X-3075 klystrons were critically examined to determine whether or not realistic redesign goals could be established. Additionally, failure analyses and field failure reports were examined to identify any design weaknesses. Results of this critical analysis indicate that substantial improvements can be made to the overall design of both the X-3060 and X-3075 klystrons. Pertinent and detailed data concerning these improvements are reported herein.

Goldfinger, A.↗

NASA NTRS1978

Modification of the Douglas Neumann program to improve the efficiency of predicting component interference and high lift characteristics

The Douglas Neumann method for low-speed potential flow on arbitrary three-dimensional lifting bodies was modified by substituting the combined source and doublet surface paneling based on Green's identity for the original source panels. Numerical studies show improved accuracy and stability for thin lifting surfaces, permitting reduced panel number for high-lift devices and supercritical airfoil sections. The accuracy of flow in concave corners is improved. A method of airfoil section design for a given pressure distribution, based on Green's identity, was demonstrated. The program uses panels on the body surface with constant source strength and parabolic distribution of doublet strength, and a doublet sheet on the wake. The program is written for the CDC CYBER 175 computer. Results of calculations are presented for isolated bodies, wings, wing-body combinations, and internal flow.

Bristow, D. R.↗

NASA NTRS1978

On improved ranging

The use of a 1 MHz range code and a narrow-passband IF filter reduces waveform distortion error by a factor of as much as 20. Along with this improvement in ranging precision, ranging accuracy is enhanced by nullifying many errors caused by equipment vagaries. The IF filter and concomitant modification of ranging system software (and in the case of the planetary ranging assembly, hardware) are the most cost-effective way of improving the current generation ranging system.

Layland, J. W.↗

NASA NTRS1978

Thermomechanical processing of HAYNES alloy No. 188 sheet to improve creep strength

Improvements in the low strain creep strength of HAYNES alloy No. 188 thin gauge sheet by means of thermomechanical processing were developed. Processing methods designed to develop a sheet with strong crystallographic texture after recrystallization and to optimize grain size were principally studied. The effects of thickness-to-grain diameter ratio and prestrain on low strain creep strength were also briefly examined. Results indicate that the most significant improvements were obtained in the sheets having a strong crystallographic texture. The low strain creep strength of the textured sheets was observed to be superior to that of standard production sheets in the 922 K to 1255 K temperature range. Tensile, stress rupture, fabricability, and surface stability properties of the experimental sheets were also measured and compared to property values reported for the baseline production sheets.

Klarstrom, D. L.↗

NASA NTRS1978

Improved detectivity of pyroelectric detectors

High detectivity single-element SBN pyroelectric detectors were fabricated. The theory and technology developments related to improved detector performance were identified and formulated. Improved methods of material characterization, thinning, mounting, blackening and amplifier matching are discussed. Detectors with detectivities of 1.3 x 10 to the 9th power square root of Hz/watt at 1 Hz are reported. Factors limiting performance and recommendations for future work are discussed.

Marshall, D. E.↗

NASA NTRS1977

On the improvement of deconvolution with digitized data using a Runge-Kutta integration scheme

A relatively simple change in the treatment of the input function in numerical integration of high-order differential equations by Runge-Kutta methods provides substantial improvements in accuracy, particularly when the forcing function is in digitized form. The Runge-Kutta-Gill coefficients are modified to incorporate the changes; with pulse-type excitations, improvements on the order of 2 to 50 times greater accuracy are demonstrated.

Houghton, J. R.↗