From Summary: "Data were obtained with five exhaust-nozzle areas and with the variable-area exhaust nozzle interlinked with the control system at conditions simulating flight at a Mach number of 0.8 and altitudes of 35,00 and 45,000 feet. Data simulating operation at zero flight Mach number at an altitude of 15,000 feet are also included. Engine component performance data are presented in addition to the overall engine performance."

From Introduction: "The general objective of this report is a study of the characteristics of the described form of peak holding control. The control has not yet been used in experimental turbojet-engine study.This study is concerned with only one method of extracting the maximum amount of information from a peak output for the purpose of maintaining that peak. The criteria sought in this control process are: maintenance of peak average output, minimum duration of time in undesirable operation, quickness in response to command to reach peak condition, least amount of excursion in the undesirable region, and type of stability."

Memorandum presenting a modified group method used to calculate the reactivity of the uranyl-fluoride-water experimental critical assemblies which are part of the Oak Ridge critical mass studies. The method relates the experimental slowing-down length for water to that in fluoride solutions and includes the effects of epithermal absorption and fission.

Memorandum presenting an investigation conducted to determine the feasibility of increasing the tip-section blade-element efficiency of a transonic rotor by reducing the blade loading for a given design inlet relative Mach number. This report primarily discusses the overall and blade-element performances of the modified rotor and compares them with the performance of the original rotor.

Highly radioactive materials have to be examined behind massive shielding to protect personnel from the intense beta and gamma fields. Experience has shown that much maintenance time can be saved by mounting equipment to cell plugs so that a single machine can be removed without the necessity of shutting down the entire cell operation. Metallographic specimen preparation and photography have been reduced to an entirely remotized procedure. Various etchants have been tried and cathodic vacuum etching has proved more satisfactory than chemical procedures. Cathodically vacuum etched surfaces are much more stable than chemically etched ones and are in various other ways more suitable for remote metallographic study. Radiation darkening of objectives and other parts of the optical system is a major problem in remote metallography. The limited amount of work done to date has not fully explained the effects of irradiation on metallographic structures. Micrographs are presented of some materials after various degrees of irradiation.

Summarizing the Observations, interpretations, and recommendations of the Authors who were assigned for a two month period to cooperate with the Colombian government in an evaluation of their uranium exploration program.

An investigation has been made at Mach numbers of 1.61 and 2.01 and Reynolds numbers from 1.7 X 10 to 7.6 X 10 to determine the pressure distributions over a 60 deg. delta wing having 20 different control configurations. Measurements were made at angles of attack from 0 deg to 15 deg for control deflections from -30 deg to 30 deg. This report presents the complete tabulated pressure data for the range of test conditions.

"An investigation has been made at Mach numbers of 1.61 and 2.01 and Reynolds numbers from 1.7 x 10(exp 6) to 7.6 x 10(exp 6) to determine the pressure distributions over a 60 degree delta wing having 20 different control configurations. Measurements were made at angles of attack from 0 to 15 degrees for control deflections from -30 to 30 degrees. This report presents the complete tabulated pressure data for the range of test conditions" (p. 1).

The present report was prepared to serve mainly as a resume of the AEC 1953 drilling project at Big Indian Wash, and a record of related activities up to early 1954.

To forestall the oxidation of graphite in HAPO reactors, a process specification provides that the oxygen concentration in pile gas should be kept to a minimum. Close control in maintaining this limit is difficult when only periodic samples are taken because laboratory results are always obtained long after any required corrections should have been made. A continuous-type analyzer that provides immediate knowledge of the oxygen concentration eliminates these time delays.

Calculated data and graphs describing the effects of batch thermal-neutron irradiations on the buildup of fission products in natural uranium, enriched uranium, and thorium are presented together with empirical equations and plots correlating total fission product activities and/or decontamination factors. Fluxes of 1012-1015 are considered.

Report presenting chemical and physical properties determined from a sample of boron-carbon-hydrogen fuel Z-244.

"This presentation is intended to reflect the current general approach of the NACA to the problems of high-temperature structures research facilities. The facilities and problems discussed apply to flight in the Mach number range from 2 to about 20. It is emphasized that this field is one in which the thinking is rapidly changing and the facilities investigations discussed, particularly for the higher temperature range, are in the exploratory stage" (p. 1).

Presentation regarding the current general approach of NACA to the problems of high-temperature structures research facilities. The field is rapidly changing and many investigations discussed are still in the exploratory stage. The main areas of importance are heating, loading, and structural model accommodation as well as having the proper research equipment and heat exchangers.

Report presenting the flutter characteristics of an untapered, 45 degree sweptback, aspect-ratio-4 wing at a range of Mach numbers. The results from NACA RM L55E19a are included along with additional information regarding the models, the tests, and the results of the flutter calculations.

"A study of the high-temperature oxidation of several aircraft construction materials was undertaken to assess the possibility of ignition under high-temperature flight conditions.Tests have been made both in open and closed jets, and, in addition, the burning of metals has been observed under static conditions in a pressurized vessel containing either air, oxygen, or nitrogen. When heated in an atmosphere of oxygen or when heated and plunged into a supersonic airstream, titanium, iron, carbon steel, and common alloys such as 4130 were found to have spontaneous-ignition temperatures in the solid phase (below melting) and they melted rapidly while burning" (p. 1).

Report presenting side-force and directional-stability characteristics of four airplane-like configurations determined at a range of Mach numbers and angles of sideslip at zero angle of attack. Two configurations had trapezoidal wing and tail surfaces and two had triangular wing and tail surfaces. The directional stability of the configurations generally decreased with increasing Mach number.

Report presenting a theoretical study of the possibility of improving the lifting efficiency of aircraft flying at supersonic speeds using indirect lift, which can be induced on the wing by the fuselage shape and/or wing end plates. Results indicated that lifting efficiency of a planar wing may be improved by favorable interference induced by lateral forces on the end plates or on the sides of the fuselage.

Report discussing testing on the drag, longitudinal stability, and lateral stability characteristics of a model of the McDonnell F4H-1 airplane. The minimum drag coefficients, neutral point, horizontal-tail-incidence range, static directional stability, and effective dihedrals are presented.

Report presenting a summary of NACA research on afterburners for turbojet engines during the past 5 years. The references present over 1000 afterburner configurations and about 3500 hours of operation. The report covers the following topics: burner-inlet diffusers, fuel-injection systems, flameholders, combustion space, combustion instability, starting and transient performance, effects of diluents, and burner-shell cooling.

From Summary: "NACA research on afterburners for turbojet engines during the past 5 years is summarized. Although most of this work has been directed toward the development of specific afterburners for various engines rather than toward the accumulation of systematic data, it has, nevertheless, provided a large fund of experimental data and experience in the field. The references cited present over 1000 afterburner configurations and some 3500 hours of operation. In the treatment of the material of this summary, the principal effort has been to convey to the reader the "know-how" acquired by research engineers in the course of the work rather than to formulate a set of design rules."

Memorandum presenting the effects of variations in cooling-passage geometry on the relations between heat flow and temperature drops within liquid-cooled turbine blades. Wall thicknesses, blade section depths, and cooling-passage sizes, shapes, and spacings were varied experimentally on a simple electric analog on which are simulated rectangular sections of blades. Results are presented in terms of temperature differences between the cooled-surface temperature and average heated-surface temperature, minimum heated-surface temperature, maximum heated-surface temperature, and maximum temperature at the centerline of the turbine blades.

Below Richland, Washington there is a gradual decrease in the concentration of beta particle emitters in the Columbia River water. The concentration of alpha particle emitters in Columbia River water averages 5 X 10⁻⁹ μl/ml at all locations. The activity of alpha particle emitters in mud samples was less than the detection limit of 3 x 10⁻⁶ μl/gm; the average activity density of beta particle emitters approximates those reported for the previous quarter.

"A program to investigate the aerodynamic heat transfer of a nonisothermal hemisphere-cylinder has been conducted in the Langley 11-inch hypersonic tunnel at a Mach number of 6.8 and a Reynolds number from approximately 0.14 x 10(6) to 1.06 x 10(6) based on diameter and free-stream conditions. The experimental heat-transfer coefficients were slightly less over the whole body than those predicted by the theory of Stine and Wanlass (NACA technical note 3344) for an isothermal surface. For stations within 45 degrees of the stagnation point the heat-transfer coefficients could be correlated by a single relation between local Stanton number and local Reynolds number" (p. 1001).