Search NASA⌕ Search

SEARCH · Search NASA

Results for “DIVING - PULL-OUTS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1961

THE INDUCED DRAG OF A DECELERATING AIRFOIL

In a recent paper in Soaring, C.A. Moeller proposed a method for determining the performance of a sailplane by recording the deceleration history of the craft following a steep dive. The advantage claimed for this method was that it would allow performance testing to be done in relatively quiescent air near the ground. It would thus be possible to eliminate the errors and uncertainties associated with conventional testing procedures, by avoiding the effects of the extraneous air currents which exist at altitude. Unfortunately, however, deceleration evaluation technique necessarily involves unsteady aerodynamics, and is thus itself subject to certain inherent error source of unknown magnitude.

DRAG↗
NASA NTRS1962

PROGRESS REPORT ON THE DEVELOPMENT OF PROTECTED CONSTRUCTION FOR HYPERSONIC VEHICLES

The structural problems of re-entry occasioned by aerodynamic heating are now generally well known. Typical of these heating problems is the environment experienced by the manned lifting vehicle re-entering from a low altitude orbit. Figure 1 shows typical curves of lower surface temperature as a function of time for a wing loading of 25 Ibs/ft(exp 2), and a lift-drag ratio of 2.5. The two curves cover a practical range of re-entry angles, the lower curve representing an ideal re-entry path with zero dive angle and the upper curve assuming a 2° error in the re-entry angle. Maneuvers for course change or correction are also added to the upper curve. Significant factors from this curve are the relationship between the maximum temperatures and the capabilities of available metallic material, and also the long re-entry time and its effect on total heat load. If a very shallow re-entry is made, maximum lower surface temperatures reach 2000°F which is just within the range of conventional superalloys. To accommodate practical re-entry angles and maneuvers, however, the temperature capability must reach about 2500°F which requires refractory metals. The re-entry time may be as high as 100 minutes, which gives total heat loads of approximately 40,000 BTU/ft(exp 2). A heat load of this magnitude, with equilibrium surface temperatures of the values shown, suggests that a lighter airframe can be constructed by dissipating the heat by radiation from the surface, rather than by absorbing it with a heat sink, or surface cooling, or ablation. Air Force programs to provide airframes for this type of environment have involved the parallel development of a number of different structural concepts. The development to be discussed here was carried out by Bell Aerosystems Company for the Fabrication Branch, Manufacturing Technology Laboratory, Directorate of Materials and Processes, Aeronautical Systems' Division, Wright-Patterson Air Force Base, Ohio, under Contract AF33(600)-40100 (Double-Wall Cooled Structure).

Reentry vehicle↗
NASA NTRS1971

Inexpensive anti-fog coating for windows

Coating applications include anti-fog protection for deep-sea diving equipment, fire protection helmets, and windows of vehicles used in hazardous environments. Basic coating composition includes liquid detergent, deionized water, and oxygen compatible fire-resistant oil. Composition prevents visor fogging under maximum metabolic load for 5 hours and longer.

Carmin, D. L., Jr.↗
NASA NTRS1972

Wind-tunnel simulation of store jettison with the aid of magnetic artificial gravity

A method employed in the simulation of jettison of stores from aircraft involving small scale wind-tunnel drop tests from a model of the parent aircraft is described. Proper scaling of such experiments generally dictates that the gravitational acceleration should ideally be a test variable. A method of introducing a controllable artificial component of gravity by magnetic means has been proposed. The use of a magnetic artificial gravity facility based upon this idea, in conjunction with small scale wind-tunnel drop tests, would improve the accuracy of simulation. A review of the scaling laws as they apply to the design of such a facility is presented. The design constraints involved in the integration of such a facility with a wind tunnel are defined. A detailed performance analysis procedure applicable to such a facility is developed. A practical magnet configuration is defined which is capable of controlling the strength and orientation of the magnetic artificial gravity field in the vertical plane, thereby allowing simulation of store jettison from a diving or climbing aircraft. The factors involved in the choice between continuous or intermittent operation of the facility, and the use of normal or superconducting magnets, are defined.

Stephens, T.↗
NASA NTRS1972

A Theory for the Function of the Spermaceti Organ of the Sperm Whale (Physeter Catodon L.)

The function of the spermaceti organ of the sperm whale is studied using a model of its acoustic system. Suggested functions of the system include: (1) action as an acoustic resonating and sound focussing chamber to form and process burst-pulsed clicks; (2) use of nasal passages in forehead for repeated recycling of air for phonation during dives and to provide mirrors for sound reflection and signal processing; and (3) use of the entire system to allow sound signal production especially useful for long range echolocofion in the deep sea.

Norris, K. S.↗
NASA NTRS1972

Design considerations for divers' breathing gas systems

Some of the design methods used to establish the gas storage, mixing, and transfer requirements for existing deep dive systems are discussed. Gas mixing systems appear essential to provide the low oxygen concentration mixtures within the converging tolerance range dictated by applications to increasing depths. Time related use of gas together with the performance of the gas transfer system insures a reasonable time frame for systems application.

Hansen, O. R.↗
NASA NTRS1972

Operation and testing of Mark 10 Mod 3 underwater breathing apparatus

Performance tests on a closed circuit, mixed gas underwater breathing apparatus are reported. The equipment is designed to provide a minimum diving duration of four hours at 1500 ft below sea surface; it senses oxygen partial pressure in the breathing gas mix and controls oxygen content of the breathing gas within narrow limits about a preset value. The breathing circuit subsystem provides respirable gas to the diver and removes carbon dioxide and moisture from the expired gas. Test results indicate undesirable variations in oxygen partial pressure with oxygen addition and insufficient carbon dioxide absorption.

Milwee, W. I., Jr.↗
NASA NTRS1972

Water landing characteristics of a model of a winged reentry vehicle

Proposed manned space shuttle vehicles are expected to land on airport runways. In an emergency situation, however, the vehicle may be required to land on water. A 1/10-scale dynamic model of a winged reentry vehicle was investigated to determine the water landing characteristics. Two configurations of the proposed vehicle were studied. Configuration 1 had a 30 deg negative dihedral of the stabilizer-elevon surface whereas configuration 2 had a 30 deg positive dihedral. Results indicate that the maximum normal accelerations for configurations 1 and 2 when landing in calm water were approximately 8g and 6g, respectively, and the maximum longitudinal accelerations were approximately 5g and 3g, respectively. A small hydroflap was needed to obtain satisfactory calm-water landings with configuration 2, whereas configuration 1 gave good landings without a hydroflap. All landings made in rough water resulted in unsatisfactory motions. For landings made in three different wave sizes, both configurations dived. The maximum normal accelerations for configurations 1 and 2 when landing in waves were -10.1g and -18.7g, respectively, and the maximum longitudinal accelerations for both configurations were approximately 13g.

Stubbs, S. M.↗
NASA NTRS1971

Analysis of pilot warning indicator performance in terminal area traffic.

Three pilot warning indicator concepts for collision hazard avoidance are analyzed using computer fast-time simulation. A hazard measure is defined based on a 1/2-g maximum horizontal acceleration, a maximum climb or dive angle of 10 deg for each aircraft, and a 20-sec warning time, through escape completion. The traffic model is based on flight tracks recorded in the Atlanta terminal area over an 11 hr period during August 1967. The basic PWI concept studied alarms on range to flashing beacons mounted on intruder aircraft as a function of relative azimuth and elevation. The alarm-hazard epoch ratio is about 17/1 to maintain the missed-alarm rate below 10%. Beacon vignetting or range-rate discrimination are shown to reduce the false-alarm rate by about 75%.

Ruetenik, J. R.↗
NASA NTRS1971

Airway structure and alveolar emptying in the lungs of sea lions and dogs.

Investigation of the effects of various cycles of compression and decompression on the alveolar volumes of the excised lungs of sea lions and dogs. The results obtained include the finding that, in comparison to dog lungs, sea lion lungs empty more completely on mild compression and much more completely on severe compression. These findings support Scholander's (1940) hypothesis that some marine mammals are protected from decompression sickness by cartilaginous reinforcement of the small airways which permits alveolar emptying during a dive, so isolating compressed gas from pulmonary capillary blood.

Denison, D. M.↗
NASA NTRS1972

EEG monitoring of a free-swimming diver at a working depth of 15 meters.

Feasibility has been shown for underwater transmission of physiological signals, using frequency modulation of carriers transmitted by return-current-density methods, as part of a personal biotelemetry system. In the prototype system, a standard IRIG subcarrier frequency (2300 Hz) was used. Power requirements, antenna design, and signal attenuation are compatible with free-ranging diving activity at distances up to 15 meters from the receiver. Extrapolation from this study and further developments are expected to substantially increase the range. Advantages of this system include subcarrier compatibility with standard IRIG demodulators using channels 1 through 10, the absence of highly specialized antenna requirements, and reasonable attenuation characteristics for transmission through the turbidity of typical seawater. Moreover, the system would not appear to be depth limited, and to be compatible with use of high-powered transponders of the same type for long-distance transmission, with or without further encoding.

Zweizig, J. R.↗
NASA NTRS1972

Analyses and tests confirm design of proprotor aircraft.

Discussion of the design features of a 300-knot tilt-proprotor VTOL aircraft having proprotors 25 ft in diameter, an empty weight of 7390 pounds, a maximum VTOL gross weight of 12,400 pounds, and a design dive speed of 300 knots. Proprotor stability analysis covering aeroelastic stability characteristics and flight mode stability characteristics is included. An evaluation of the proprotor design is made on the basis of aerodynamic and aeroelastic model tests and full-scale performance tests. The test results and other obtained research data suggest the readiness of this aircraft design for construction and flight tests.

Edenborough, H. K.↗
NASA NTRS1973

Studies of the inner shelf and coastal sedimentation environment of the Beaufort Sea from ERTS-1

The author has identified the following significant results. Northward flowing rivers of Alaska inundate extensive areas of sea ice during spring breakup. This process has been studied under the ERTS-1 program. Drainage of large volumes of fresh water through the ice at holes and cracks (strudel) causes scour depressions, over 4 m deep, and up to 20 m across in the sea floor below. Strudel scours occur within 30 km of river mouths, generally in areas where ERTS-1 imagery shows less potential for drifting ice to scour the bottom than elsewhere. The shapes and distribution patterns of strudel scours correspond with those of strudel seen in the ice canopy. Densities of scours are highest in the inner areas of overlfow. But strudel scours also occur outside of overflow areas mapped during the last several years. These must be very old. One strudel scour investigated by diving is surrounded by a rim, has vertical walls exposing a tundra horizon, and terminates at a gravel layer 4 m below the lagoon floor. Another terminates at a semi-consolidated layer of silty clay. The gravel and silty clay are pre-Holocene deposits. Mixing of Holocene marine with older sediments by vertical strudel flow causes great variability in sediment types over small areas. These observations complicate interpretation of shallow water deposits of cold climates.

Reimnitz, E.↗
NASA NTRS1973

Human eye movements during various forms of linear acceleration and weightlessness

Eye movements of human subjects were recorded electronystagmographically in complete darkness during rectilinear horizontal accelerations as achieved in cars on the ground and also during aircraft parabolic flight. The results were compared to the movements of blinded goldfish subjected to similar changes of gravitoinertial forces. The results indicate that there is a human correlation with the gravity reference response of fish. During horizontal forward accelerations on the ground the human eyes turn downward and during horizontal backward acceleration the eyes turn upward. The human eye response to g-loads below 1 g and to weightlessness is the reverse of the tilt of the fish. While fish dive down during low g, or loop forward during weightlessness, the eyes of subjects sitting upright in an aircraft which flies at 0 g move upward.

Vonbaumgarten, R. J.↗
NASA NTRS1974

Cardiovascular response to apneic immersion in cool and warm water

The influence of prior exposure to cool water and the influence of lung volume on the responses to breath holding were examined. The bradycardia and vasoconstriction that occur during breath-hold diving in man are apparently the resultant of stimuli from apnea, relative expansion of the thorax, lung volume, esophageal pressure, face immersion, and thermal receptor stimulation. It is concluded that the bradycardia and vasoconstriction associated with breath holding during body immersion are not attenuated by a preexisting bradycardia and vasoconstriction due to cold.

Folinsbee, L.↗
NASA NTRS1974

Analytic model for assessing the thermal performance of scuba divers

A biothermal model with a physically-controlled subsystem and a dynamically-controlled subsystem is developed to simulate the thermoregulatory system of man under immersed conditions. The model is consistent with experimental data for seminude subjects immersed to neck in cool to temperate water and for 'wet-suited' subjects immersed to neck in cold water. Equations are derived for predicting body temperatures under various dive conditions.

Montgomery, L. D.↗
NASA NTRS1974

Integrated lift/drag controller for aircraft

A system for altering the lift/drag characteristics of powered aircraft to provide a safe means of glide path control includes a control device integrated for coordination action with the aircraft throttle. Such lift/drag alteration devices as spoilers, dive brakes, and the like are actuated by manual operation of a single lever coupled with the throttle for integrating, blending or coordinating power control. Improper operation of the controller is inhibited by safety mechanisms.

Olcott, J. W.↗