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 Serial/Series Title: NACA Technical Reports
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Aeronautic instruments. Section VIII : recent developments and outstanding problems

Aeronautic instruments. Section VIII : recent developments and outstanding problems

Date: 1923
Creator: Hunt, F. L.
Description: This report is section VIII of a series of reports on aeronautic instruments. The preceding reports in this series have discussed in detail the various types of aeronautic instruments which have reached a state of practical development such that they have already found extensive use. It is the purpose of this paper to discuss briefly some of the more recent developments in the field of aeronautic instrument design and to suggest some of the outstanding problems awaiting solution.
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Aeronautic Power Plant Investigations

Aeronautic Power Plant Investigations

Date: May 1, 1917
Creator: Dickinson, H. C.
Description: Report presents the design of radiators, spark plugs and test equipment used to test the performance of aeronautic engines at high altitudes.
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Air conditions close to the ground and the effect on airplane landings

Air conditions close to the ground and the effect on airplane landings

Date: April 3, 1934
Creator: Thompson, F L; Peck, W C & Beard, A P
Description: This report presents the results of an investigation undertaken to determine the feasibility of making glide landings in gusty air. Wind velocities were measured at several stations between the ground and a height of 51 feet, and flight tests were made to determine the actual influence of gusts on an airplane gliding close to the ground.
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Air-consumption parameters for automatic mixture control of aircraft engines

Air-consumption parameters for automatic mixture control of aircraft engines

Date: September 1, 1944
Creator: Shames, Sidney J
Description: Data obtained from Navy calibration tests of an 18-cylinder, two-row, radial engine of 3350-cubic-inch displacement and a 14-cylinder, two-row, radial engine of 2600-cubic-inch displacement (carburetor types) were analyzed to show the correlation between the air consumption of these engines and the parameters that evaluate the air consumption from intake-manifold temperature and pressure, exhaust back pressure, and engine speed.
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Air flow around finned cylinders

Air flow around finned cylinders

Date: November 7, 1935
Creator: Brevoort, M J & Rollin, Vern G
Description: Report presents the results of a study made to determine the air-flow characteristics around finned cylinders. Air-flow distribution is given for a smooth cylinder, for a finned cylinder having several fin spacings and fin widths, and for a cylinder with several types of baffle with various entrance and exit shapes. The results of these tests show: that flow characteristics around a cylinder are not so critical to changes in fin width as they are to fin spacing; that the entrance of the baffle has a marked influence on its efficiency; that properly designed baffles increase the air flow over the rear of the cylinder; and that these tests check those of heat-transfer tests in the choice of the best baffle.
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Air flow in a separating laminar boundary layer

Air flow in a separating laminar boundary layer

Date: December 1, 1934
Creator: Schubauer, G. B.
Description: The speed distribution in a laminar boundary layer on the surface of an elliptic cylinder, of major and minor axes 11.78 and 3.98 inches, respectively, has been determined by means of a hot-wire anemometer. The direction of the impinging air stream was parallel to the major axis. Special attention was given to the region of separation and to the exact location of the point of separation. An approximate method, developed by K. Pohlhausen for computing the speed distribution, the thickness of the layer, and the point of separation, is described in detail; and speed-distribution curves calculated by this method are presented for comparison with experiment.
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Air flow in the boundary layer near a plate

Air flow in the boundary layer near a plate

Date: March 1936
Creator: Dryden, Hugh L.
Description: The published data on the distribution of speed near a thin flat plate with sharp leading edge placed parallel to the flow (skin friction plate) are reviewed and the results of some additional measurements are described. The purpose of the experiments was to study the basic phenomena of boundary-layer flow under simple conditions.
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Air flow in the boundary layer of an elliptic cylinder

Air flow in the boundary layer of an elliptic cylinder

Date: August 6, 1938
Creator: Schubauer, G B
Description: The boundary layer of an elliptic cylinder of major and minor axis 11.78 and 3.98 inches, respectively, was investigated in air stream in which the turbulence could be varied. Conditions were arranged so that the flow was two-dimensional with the major axis of the ellipse parallel to the undisturbed stream. Speed distributions across the boundary layer were determined with a hot-wire anemometer at a number of positions about the surface for the lowest and highest intensities of turbulence, with the air speed in both cases sufficiently high to produce a turbulent boundary layer over the downstream part of the surface. The magnitude and the frequency of the speed fluctuations in the boundary layer were also measured by the use of the conventional type of hot-wire turbulence apparatus. Stream turbulence was found to affect both the nature of transition from laminar to turbulent flow in the layer and the position on the surface at which transition occurred. Transition was then investigated in detail with stream turbulence of several different scales and intensities.
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Air flow through poppet valves

Air flow through poppet valves

Date: 1918
Creator: Lewis, G W & Nutting, E M
Description: Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.
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Air force and moment for N-20 wing with certain cut-outs

Air force and moment for N-20 wing with certain cut-outs

Date: November 29, 1926
Creator: Smith, R H
Description: The airplane designer often finds it necessary, in meeting the requirements of visibility, to remove area or to otherwise locally distort the plan or section of an airplane wing. This report, prepared for the Bureau of Aeronautics January 15, 1925, contains the experimental results of tests on six 5 by 30 inch N-20 wing models, cut out or distorted in different ways, which were conducted in the 8 by 8 foot wind tunnel of the Navy Aerodynamical Laboratory in Washington in 1924. The measured and derived results are given without correction for vl/v for wall effect and for standard air density, p=0.00237 slug per cubic foot.
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Air force tests of sperry messenger model with six sets of wings

Air force tests of sperry messenger model with six sets of wings

Date: 1928?~
Creator: Shoemaker, James M
Description: The purpose of this test was to compare six well-known airfoils, the R.A.F 15, U.S.A. 5, U.S.A. 27, U.S.A. 35-B, Clark Y, and Gottingen 387, fitted to the Sperry Messenger model, at full scale Reynolds number as obtained in the variable density wind tunnel of the National Advisory Committee for Aeronautics; and to determine the scale effect on the model equipped with all the details of the actual airplane. The results show a large decrease in minimum drag coefficient upon increasing the Reynolds number from about one-twentieth scale to full scale. Maximum lift coefficient was increased with increasing scale for all the airfoils except the Gottingen 387, for which it was slightly decreased. A comparison is made between the results of these tests and those obtained from tests made in this tunnel on airfoils alone. (author).
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Air forces and moments on triangular and related wings with subsonic leading edges oscillating in supersonic potential flow

Air forces and moments on triangular and related wings with subsonic leading edges oscillating in supersonic potential flow

Date: 1952?~
Creator: Watkins, Charles E & Berman, Julian N
Description: This analysis treats the air forces and moments in supersonic potential flow on oscillating triangular wings and a series of sweptback and arrow wings with subsonic leading edges and supersonic trailing edges. For the wings undergoing sinusoidal torsional oscillations simultaneously with vertical translations, the linearized velocity potential is derived in the form of a power series in terms of a frequency parameter. This method can be useful for treatment of similar problems for other plan forms and for wings undergoing other sinusoidal motions. For triangular wings, as many terms of such a series expansion as may be derived can be determined; however, the terms after the first few become very cumbersome. Closed expressions that include the reduced frequency to the fifth power, an order which is sufficient for a large class of practical application, are given for the velocity potential and for the components of chordwise section force and moment coefficients. These wings are found to exhibit the possibility of undamped torsional oscillations for certain ranges of Mach number and locations of the axis of rotation. The ranges of these parameters are delineated for triangular wings.
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Air forces, moments and damping on model of fleet airship Shenandoah

Air forces, moments and damping on model of fleet airship Shenandoah

Date: 1922~
Creator: Zahm, A F; Smith, R H & Louden, F A
Description: To furnish data for the design of the fleet airship Shenandoah, a model was made and tested in the 8 by 8 foot wind tunnel for wind forces, moments, and damping, under conditions described in this report. The results are given for air of standard density. P=0.00237 slugs per cubic foot with vl/v correction, and with but a brief discussion of the aerodynamic design features of the airship.
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The air forces on a model of the sperry messenger airplane without propeller

The air forces on a model of the sperry messenger airplane without propeller

Date: 1926?~
Creator: Munk, Max M & Diehl, Walter S
Description: This is a report on a scale effect research which was made in the variable-density wind tunnel of the National Advisory Committee for Aeronautics at the request of the Army Air Service. A 1/10 scale model of the sperry messenger airplane with USA-5 wings was tested without a propeller at various Reynolds numbers up to the full scale value. Two series of tests were: the first on the original model which was of the usual simplified construction, and the second on a modified model embodying a great amount of detail. The experimental results show that the scale effect is almost entirely confined to the drag. It was also found that the model should be geometrically similar to the full-scale airplane if the test data are to be directly applicable to full scale.
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The air forces on a systematic series of biplane and triplane cellule models

The air forces on a systematic series of biplane and triplane cellule models

Date: 1927
Creator: Munk, Max M
Description: The air forces on a systematic series of biplane and triplane cellule models are the subject of this report. The test consist in the determination of the lift, drag, and moment of each individual airfoil in each cellule, mostly with the same wing section. The magnitude of the gap and of the stagger is systematically varied; not, however, the decalage, which is zero throughout the tests. Certain check tests with a second wing section make the tests more complete and conclusions more convincing. The results give evidence that the present army and navy specifications for the relative lifts of biplanes are good. They furnish material for improving such specifications for the relative lifts of triplanes. A larger number of factors can now be prescribed to take care of different cases.
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Air propellers in yaw

Air propellers in yaw

Date: January 1, 1937
Creator: Lesley, E P; Worley, George F & Moy, Stanley
Description: Report presents the results of tests conducted at Stanford University of a 3-foot model propeller at four pitch settings and at 0 degree, 10 degrees, 20 degrees, and 30 degrees yaw. In addition to the usual propeller coefficients, cross-wind and vertical forces and yawing, pitching, and rolling moments were determined about axes having their origin at the intersection of the blade axis and the axis of rotation. The tests showed that the maximum efficiency was reduced only slightly for angles of yaw up to 10 degrees but that at 30 degrees yaw the loss in efficiency was about 10 percent. In all cases the cross-wind force was found to be greater than the cross-wind component of the axial thrust. With a yawed propeller an appreciable thrust was found for v/nd for zero thrust at zero yaw. Yawing a propeller was found to induce a pitching moment that increased in magnitude with yaw.
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Aircraft accidents.method of analysis

Aircraft accidents.method of analysis

Date: January 1, 1937
Creator: unknown
Description: This report is a revision of NACA-TR-357. It was prepared by the Committee on Aircraft Accidents. The purpose of this report is to provide a basis for the classification and comparison of aircraft accidents, both civil and military.
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Aircraft accidents : method of analysis

Aircraft accidents : method of analysis

Date: January 1, 1929
Creator: unknown
Description: This report on a method of analysis of aircraft accidents has been prepared by a special committee on the nomenclature, subdivision, and classification of aircraft accidents organized by the National Advisory Committee for Aeronautics in response to a request dated February 18, 1928, from the Air Coordination Committee consisting of the Assistant Secretaries for Aeronautics in the Departments of War, Navy, and Commerce. The work was undertaken in recognition of the difficulty of drawing correct conclusions from efforts to analyze and compare reports of aircraft accidents prepared by different organizations using different classifications and definitions. The air coordination committee's request was made "in order that practices used may henceforth conform to a standard and be universally comparable." the purpose of the special committee therefore was to prepare a basis for the classification and comparison of aircraft accidents, both civil and military. (author).
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Aircraft accidents : method of analysis

Aircraft accidents : method of analysis

Date: January 1, 1931
Creator: unknown
Description: The revised report includes the chart for the analysis of aircraft accidents, combining consideration of the immediate causes, underlying causes, and results of accidents, as prepared by the special committee, with a number of the definitions clarified. A brief statement of the organization and work of the special committee and of the Committee on Aircraft Accidents; and statistical tables giving a comparison of the types of accidents and causes of accidents in the military services on the one hand and in civil aviation on the other, together with explanations of some of the important differences noted in these tables.
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Aircraft compass characteristics

Aircraft compass characteristics

Date: January 1, 1937
Creator: Peterson, John B. & Smith, Clyde W.
Description: A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Characteristics of Navy aircraft compasses IV to IX and some other compasses are shown for the range of temperatures experienced in flight. Results of flight tests are presented. These results indicate that the characteristic most desired in a steering compass is a short period and, in a check compass, a low overswing.
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Aircraft power-plant instruments

Aircraft power-plant instruments

Date: January 1, 1934
Creator: Sontag, Harcourt & Brombacher, W. G.
Description: This report supersedes NACA-TR-129 which is now obsolete. Aircraft power-plant instruments include tachometers, engine thermometers, pressure gages, fuel-quantity gages, fuel flow meters and indicators, and manifold pressure gages. The report includes a description of the commonly used types and some others, the underlying principle utilized in the design, and some design data. The inherent errors of the instrument, the methods of making laboratory tests, descriptions of the test apparatus, and data in considerable detail in the performance of commonly used instruments are presented. Standard instruments and, in cases where it appears to be of interest, those used as secondary standards are described. A bibliography of important articles is included.
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Aircraft rate-of-climb indicators

Aircraft rate-of-climb indicators

Date: January 1, 1939
Creator: Johnson, Daniel P.
Description: The theory of the rate-of-climb indicator is developed in a form adapted for application to the instrument in its present-day form. Compensations for altitude, temperature, and rate of change of temperature are discussed from the designer's standpoint on the basis of this theory. Certain dynamic effects, including instrument lag, and the use of the rate-of-climb indicator as a statoscope are also considered. Modern instruments are described. A laboratory test procedure is outlined and test results are given.
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Aircraft speed instruments

Aircraft speed instruments

Date: January 1, 1933
Creator: Beij, K Hilding
Description: This report presents a concise survey of the measurement of air speed and ground speed on board aircraft. Special attention is paid to the pitot-static air-speed meter which is the standard in the United States for airplanes. Air-speed meters of the rotating vane type are also discussed in considerable detail on account of their value as flight test instruments and as service instruments for airships. Methods of ground-speed measurement are treated briefly, with reference to the more important instruments. A bibliography on air-speed measurement concludes the report.
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Aircraft woods: their properties, selection, and characteristics

Aircraft woods: their properties, selection, and characteristics

Date: January 1, 1931
Creator: Markwardt, L J
Description: Strength values of various woods for aircraft design for a 15 per cent moisture condition of material and a 3-second duration of stress are presented, and also a discussion of the various factors affecting the values. The toughness-test method of selecting wood is discussed, and a table of acceptance values for several species is given.
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