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An Experimental Investigation of Flow Across Tube Banks

Description: Flow across tube banks was investigated by surveys of total dynamic and static pressure by visualization of the flow through the use of titanium tetrachloride smoke, by thermocouple surveys of heated tubes, and by hot-wire surveys of both heated and unheated tubes. It was found that turbulence increased as the depth of the bank increased and that the broad wake behind each tube affected flow over the succeeding tubes.
Date: March 1942
Creator: Brevoort, M. J. & Tifford, A. N.
Partner: UNT Libraries Government Documents Department

Test-stand investigation of cooling characteristics and factors affecting temperature distribution of a double-row aircraft engine

Description: Report presenting testing of a double-row radial air-cooled engine to investigate overall cooling characteristics and to analyze what variations in temperature distribution were caused by variations in cooling-air pressure drop, power, and fuel-air ratio. Testing occurred over a range of engine powers.
Date: March 1946
Creator: Sipko, Michael A.; Hickel, Robert O. & Jones, Robert J.
Partner: UNT Libraries Government Documents Department

Tests and approximate analysis of bending stresses due to torsion in a D-section box

Description: From Summary: "Strain surveys were made on the stringers reinforcing a D-section box loaded in torsion and restrained from warping at the root. On the basis of the tests, a procedure is suggested for estimating the bending stresses due to torsion that occur near the flange of a D-section box. A similar test of a triangular-section box showed that for such a section there were no significant bending stresses due to torsion, a fact which was also shown theoretically."
Date: May 1944
Creator: Duberg, John E. & Brilmyer, Harold G.
Partner: UNT Libraries Government Documents Department

The problem of thermal-expansion stresses in reinforced plastics

Description: Report presenting an analysis of the failure of adhesive bonds and its relation to boundary stress concentrations. A variety of material combinations, including metals and plastics, were examined and stress tested. The method of computing the thermal coefficients is applied to mixtures and especially to reinforced plastics.
Date: June 1942
Creator: Turner, P. S.
Partner: UNT Libraries Government Documents Department

Some systematic model experiments on the porpoising characteristics of flying-boat hulls

Description: From Summary: "This report presents the results of systematic model experiments on the hydrodynamic characteristics of flying boats, aimed primarily at developing a comprehensive view of the factors influencing porpoising and of their relative importance. The experiments 'radiated' from a given reference ship; they embrace changes, over reasonably wide ranges, in the value of each of a number of variables, treated independently. The experimental results are summarized in a series of 25 figures, each of which gives the complete data for all the modifications of one variable."
Date: June 1943
Creator: Davidson, Kenneth S. M. & Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Statistical Analysis of the Characteristics of Repeated Gusts in Turbulent Air

Description: Statistical methods were applied to acceleration and airspeed data obtained with the XC-35 airplane during flights in turbulent air within convective clouds in order to determine the characteristics of repeated or closely spaced gusts pertinent to design problems. Results indicated that, in turbulent air within convective cloud, gusts tend to be contiguous and are seldom found isolated in space. Over-all average spacing between repeated gusts was in good agreement with twice the average gust-gradient distance of 10 chords used in present design.
Date: November 1945
Creator: Moskovitz, A. I. & Peiser, A. M.
Partner: UNT Libraries Government Documents Department

Static-thrust tests of six rotor-blade designs on a helicopter in the Langley full-scale tunnel

Description: Report discusses the results of testing of measurements of the static-thrust performance of six sets of rotor blades mounted on a helicopter fuselage. The blades differed in surface condition, pitch distribution, airfoil section, plan form, and solidarity. Results indicated that rotor-blade surface condition is important for performance and the optimum performance will only be obtained if the blades have a smooth, accurately contoured surface that will not deform during flight.
Date: September 1945
Creator: Dingeldein, Richard C. & Schaefer, Raymond F.
Partner: UNT Libraries Government Documents Department

Summary report on the induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Description: Report presenting investigations of a full-scale air-cooled aircraft-engine cylinder of 202-cubic-inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. Results regarding the maximum permissible engine performance, engine temperatures, and constant inlet-air pressure investigations are provided.
Date: August 15, 1942
Creator: Rothrock, Addison M. & Jones, Anthony W.
Partner: UNT Libraries Government Documents Department

Progress report on strength and creep of special ceramic bodies in tension at elevated temperatures

Description: Report presenting an investigation for the determination of the behavior of ceramic bodies in tension at elevated temperatures for the purpose of determining data for the design of ceramic blades for gas turbines. Observations were made of six special ceramic bodies in order to determine their tensile strength and creep during prolonged loading under a range of stresses and temperatures.
Date: June 1946
Creator: Geller, R. F. & Burdick, M. D.
Partner: UNT Libraries Government Documents Department

The resistance of three series of flying boat-hulls as affected by length-beam ratio

Description: Report presents correlation of data obtained from several independent length-beam-ratio investigations to determine the general effect of length-beam ratio on the resistance characteristics of three series of flying-boat hulls. An optimum length-beam ratio was found beyond which no further reduction in hydrodynamic resistance occurred. The optimum ratio depended on the hull lines of any given mode series.
Date: October 1945
Creator: Land, Norman S.; Bidwell, Jerold M. & Goldenbaum, David M.
Partner: UNT Libraries Government Documents Department

Significance of alkylate-replacement values of aviation fuel components

Description: Report discusses the significance of alkylate-replacement values and to illustrate methods of estimating these values. Equations expressing alkylate-replacement values and the estimated effect on engine performance resulting from replacement of alkylate is discussed and test data is provided in F-3 and F-4 laboratory engines. The researchers found that "alkylate-replacement value depends not only upon the rating of the fuel component that is replacing the alkylate but also upon the ratings of the alkylate and the base fuel."
Date: December 1944
Creator: Sanders, Newell D.
Partner: UNT Libraries Government Documents Department

Shear-lag tests of two box beams with corrugated covers loaded to failure

Description: From Summary: "Strain measurements were made on the compression side of two box beams with corrugated aluminum-alloy covers loaded to failure. Angles formed from sheet were used for corner flanges in beam 1; whereas extruded angles were used in beam 2. Failure in each beam occurred in the corner angle at a stress that was above the compressive yield stress for the material."
Date: January 1944
Creator: Chiarito, Patrick T.
Partner: UNT Libraries Government Documents Department

Single-cylinder engine tests of porous chrome-plated cylinder barrels with special bore coatings for radial air-cooled engines

Description: Report discussing a series of single-cylinder engine tests to determine the effect of special surface coatings in porous chrome-plated cylinder barrels on oil consumption and ring wear. The coating materials were selected for their bearing and lubrication properties and on their applicability to processing. The surface coatings tested were lead overplates, silver overplates, and colloidal graphite base paint.
Date: January 1946
Creator: Johnson, Robert L. & Anderson, Roy I.
Partner: UNT Libraries Government Documents Department

Standard method of graphical presentation of centrifugal compressor performance

Description: Report on the NACA recommended method for comparing the performance of centrifugal compressors. The most important indices of compressor performance are the adiabatic temperature rise ratio or adiabatic efficiency, the adiabatic shaft efficiency, and the pressure ratio, which incorporate many other parameters. Recommendations for reporting on compressor effectiveness and characteristics are provided.
Date: August 1945
Creator: NACA Subcommittee on Supercharger Compressors
Partner: UNT Libraries Government Documents Department

Standard procedures for rating and testing centrifugal compressors

Description: Report on the NACA test-rig installation, measurements, instrumentation, test procedure, methods of calculation, and presentation of data for rating and testing centrifugal superchargers. Special precautions for certain portions of testing are also provided.
Date: August 1945
Creator: NACA Subcommittee on Supercharger Compressors
Partner: UNT Libraries Government Documents Department

Some systematic model experiments of the bow-spray characteristics of flying-boat hulls operating at low speeds in waves

Description: Report discusses the results of testing on several models of flying boats, the XPB2M-1, the XPBB-1, the JRM-1, and 11 other models to determine the effect of bow form on the amount of spray thrown onto the windshield of a flying boat in rough water. Several recommendations for reducing the height and volume of spray are provided. Any change in the hull form that softens the impact between the hull and waves seems to reduce the spray.
Date: December 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Some yawing tests of a 1/30-scale model of the hull of the XPB2M-1 flying boat

Description: Report discusses the results of yawing tests on a model of the complete hull of the XPB2M-1. The tests indicated that there was a tendency toward directional instability in the vicinity of the hump. The researchers concluded that at a certain range, the curves of yawing moment are discontinuous, and this has led to difficulty in preliminary test flights.
Date: July 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Relation of preignition and knock to allowable engine temperatures

Description: From Summary: "The results are given of an investigation of some of the limitations that now prevent increases in the temperature level of engine cylinder heads, and a review of previous work in the field is included to supplement these results. Attention was given, in particular, to the effects of fuel knock and surface ignition on cylinder temperatures and the effects of cylinder temperatures on performance. Data were obtained from a Wright C9GC air-cooled cylinder and from a Lycoming O-1230 liquid-cooled cylinder."
Date: July 1943
Creator: Biermann, Arnold E. & Corrington, Lester C.
Partner: UNT Libraries Government Documents Department

Response of helicopter rotors to periodic forces

Description: Report explores the periodic forces that helicopter rotors are subjected to, both horizontal and vertical, and several configurations and material combinations of blades are described. The vibrations and exciting forces are demonstrated through calculations and explored with combinations of one, two, three, and four blades.
Date: March 1945
Creator: Kelley, Bartram
Partner: UNT Libraries Government Documents Department

Representative operating charts of propellers tested in the NACA 20-foot propeller-research tunnel

Description: Report presents the results of tests of full-scale propellers made in the 20-foot propeller-research tunnel (PRT) at the Langley Memorial Aeronautical Laboratory. The power coefficients of all dual-rotating propellers in the report represent the sum of the power coefficients of the front and rear propellers and are for the test conditions in which blade angles of the front and rear propellers were set to absorb approximately equal power at peak efficiency only.
Date: September 1943
Creator: Gray, W. H. & Mastrocola, Nicholas
Partner: UNT Libraries Government Documents Department

Resistance tests of models of three flying-boat hulls with a length-beam ratio of 10.5

Description: Report presenting testing of models of three flying-boat hulls with a length-beam ratio of 10.5. Testing occurred at two depths of step and two angles of dead rise. Results regarding resistance, trimming-moment, and wetted-length data for general fixed-trim and free-to-trim tests at load coefficients up to 4.0 are provided.
Date: September 1945
Creator: Bidwell, Jerold M. & Goldenbaum, David M.
Partner: UNT Libraries Government Documents Department

Shear-lag tests of a box beam with a highly cambered cover in tension

Description: Report discusses the results of bending tests on an open box beam designed to fail on the highly cambered tension side. Results in the elastic range and ultimate-strength test are provided. The stringer stresses near the root were in fair agreement with stresses calculated by shear-lag theory and the ultimate tensile strength developed by the beam was only a little higher than the tensile yield stress of the material.
Date: July 1945
Creator: Peterson, James P.
Partner: UNT Libraries Government Documents Department

The Selection of Propellers for High Thrust at Low Airspeed

Description: Problem of improving thrust at low speeds is primarily one of reducing angle of attack of operation of sections to improve L/D or reducing blade helix angle. An analysis, based on recent propeller data, is presented for determining improvements in thrust or efficiency which could be obtained by increased number of blades, increased blade width, increased diameter, dual rotation, and two-speed gearing. All methods were found very effective, particularly two-speed gearing.
Date: October 1941
Creator: Biermann, David & Conway, Robert N.
Partner: UNT Libraries Government Documents Department

Tables of stiffness and carry-over factor for flat rectangular plates under compression

Description: Report presents tables of stiffness and carry-over factor for infinitely long flat plates subjected to a uniformly distributed longitudinal compressive load. The tables can be used to help solve problems in the stability of structures made out of plates under compression.
Date: November 1943
Creator: Kroll, W. D.
Partner: UNT Libraries Government Documents Department