Investigation of Icing Characteristics of Typical Light Airplane Engine Induction Systems (open access)

Investigation of Icing Characteristics of Typical Light Airplane Engine Induction Systems

"The icing characteristics of two typical light-airplane engine induction systems were investigated using the carburetors and manifolds of engines in the horsepower ranges from 65 to 85 and 165 to 185. The smaller system consisted of a float-type carburetor with an unheated manifold and the larger system consisted of a single-barrel pressure-type carburetor with an oil-jacketed manifold. Carburetor-air temperature and humidity limits of visible and serious Icing were determined for various engine power conditions" (p. 1).
Date: February 1949
Creator: Coles, Willard D.
System: The UNT Digital Library
Aerodynamic Effects Caused by Icing of an Unswept NACA 65A004 Airfoil (open access)

Aerodynamic Effects Caused by Icing of an Unswept NACA 65A004 Airfoil

From Summary: "The effects of ice formations on the section lift, drag, and pitching-moment coefficients of an unswept NACA 65A004 airfoil section of 6-foot chord were studied.. The magnitude of the aerodynamic penalties was primarily a function of the shape and size of the ice formation near the leading edge of the airfoil. The exact size and shape of the ice formations were determined photographically and found to be complex functions of the operating and icing conditions."
Date: February 1958
Creator: Gray, Vernon H. & von Glahn, Uwe H.
System: The UNT Digital Library
Icing Limit and Wet-Surface Temperature Variation for Two Airfoil Shapes Under Simulated High-Speed Flight Conditions (open access)

Icing Limit and Wet-Surface Temperature Variation for Two Airfoil Shapes Under Simulated High-Speed Flight Conditions

Note presenting an experimental study of the wet-surface temperature and stream conditions that result in ice-free surfaces for bodies in flight through icing clouds, and the results obtained are compared with values calculated using an analytical method. Two symmetrical airfoil models, one of diamond shape and the other of double-circular-arc contour, were used in the investigation. Results regarding the chordwise variation of pressure distribution, chordwise variation of recovery factor, the diamond airfoil, and circular-arc airfoil are provided.
Date: February 1955
Creator: Coles, Willard D.
System: The UNT Digital Library
De-Icing Effectiveness of External Electric Heaters for Propeller Blades (open access)

De-Icing Effectiveness of External Electric Heaters for Propeller Blades

Note presenting an investigation in the icing research tunnel to determine the icing protection provided by external rubber-clad blade heaters at several icing, heating, and propeller operating conditions. Data are presented to show the effect of propeller speed, ambient-air temperature, liquid-water concentration, heating-power density, duration of heating, and total cycle times on the power requirements and de-icing performance of the blade heaters.
Date: February 1948
Creator: Lewis, James P.
System: The UNT Digital Library
A flight investigation of the practical problems associated with porous-leading-edge suction (open access)

A flight investigation of the practical problems associated with porous-leading-edge suction

From Summary: "A flight investigation has been made of the practical problems associated with the use of porous-leading-edge suction. The wing leading edge of the test airplane was porous over approximately 83 percent of the span and the first 8 percent of the chord on the upper surface. Various other extents of suction area within these limits were also tested."
Date: February 1954
Creator: Hunter, Paul A. & Johnson, Harold I.
System: The UNT Digital Library
Correlations Among Ice Measurements, Impingement Rates Icing Conditions, and Drag Coefficients for Unswept NACA 65A004 Airfoil (open access)

Correlations Among Ice Measurements, Impingement Rates Icing Conditions, and Drag Coefficients for Unswept NACA 65A004 Airfoil

"An empirical relation has been obtained by which the change in drag coefficient caused by ice formations on an unswept NACA 65A004 airfoil section can be determined from the following icing and operating conditions: icing time, airspeed, air total temperature, liquid-water content, cloud droplet impingement efficiencies, airfoil chord length, and angles of attack. The correlation was obtained by use of measured ice heights and ice angles. These measurements were obtained from a variety of ice formations, which were carefully photographed, cross-sectioned, and weighed" (p. 1).
Date: February 1958
Creator: Gray, Vernon H.
System: The UNT Digital Library
Penetration of Air Jets Issuing from Circular, Square, and Elliptical Orifices Directed Perpendicularly to an Air Stream (open access)

Penetration of Air Jets Issuing from Circular, Square, and Elliptical Orifices Directed Perpendicularly to an Air Stream

From Summary: "An experimental investigation was conducted to determine the penetration of air jets directed perpendicularly to an air stream. Jets issuing from circular, square, and elliptical orifices were investigated and the jet penetration at a position downstream of the orifice was determined- as a function of jet density, jet velocity, air-stream density, air-stream velocity, effective jet diameter, and orifice flow coeffIcient. The jet penetrations were determined for nearly constant values of air-stream density at three tunnel-air velocities arid for a large range of jet velocities and densities."
Date: February 1950
Creator: Ruggeri, Robert S.; Callaghan, Edmund E. & Bowden, Dean T.
System: The UNT Digital Library
Impingement of Water Droplets on a Rectangular Half Body in a Two-Dimensional Incompressible Flow Field (open access)

Impingement of Water Droplets on a Rectangular Half Body in a Two-Dimensional Incompressible Flow Field

"Trajectories of water droplets moving in the ideal two-dimensional flow field ahead of a body of rectangular cross section and infinite extent in the downstream direction have been calculated by means of a differential analyzer. Data on collection efficiency and distribution of water impingement are presented" (p. 1).
Date: February 1956
Creator: Lewis, William & Brun, Rinaldo J.
System: The UNT Digital Library
Loads and Calculations of Army Airplanes (open access)

Loads and Calculations of Army Airplanes

By comparing airplanes of known strength that have resisted all the usual and even extreme air loads with those that under like conditions were found to be insufficiently strong, the researchers, aided by scientific investigations, developed standards which are satisfactory for the calculation of airplane structures. Given here are standards applicable to loads on wing trusses, load factors for use in stress analysis, load factors required in sand testing, loads on control surfaces, loads on wing ribs, loads on landing gear, and rigidity of materials.
Date: February 1921
Creator: Stelmachowski
System: The UNT Digital Library
The Theory of the Screw Propeller (open access)

The Theory of the Screw Propeller

Given here is a brief review of the fundamental principles of the propeller slip-stream theory and its further development through later researches, which demonstrate the connection between the propeller slip-stream theory and Frounde's so-called 'propeller blade theory.' The propeller slip-stream theory, especially in its improved form, now gives us the basis for determining the mutual influence of the parts of the blade, so that, in calculating the shape of the blade, we can get along with certain section characteristics, which have been determined once and for all. It is argued that new theories present the possibility of investigating the phenomena in the vicinity of the propeller, allowing us to calculate its action on the basis of fewer experimental values.
Date: February 1922
Creator: Betz, A.
System: The UNT Digital Library
Air force and three moments for F-5-L Seaplane (open access)

Air force and three moments for F-5-L Seaplane

From Introduction: "A model of the F-5-L seaplane was made, verified, and tested at 40 miles an hour in the 8' x 8' tunnel for lift and drag, also for pitching, yawing and rolling moments. Subsequently, the yawing moment test was repeated with a modified fin. The results are reported without VL scale correction."
Date: February 1922
Creator: unknown
System: The UNT Digital Library
Surface area coefficients for airship envelopes (open access)

Surface area coefficients for airship envelopes

"In naval architecture, it is customary to determine the wetted surface of a ship by means of some formula which involves the principal dimensions of the design and suitable constants. These formulas of naval architecture may be extended and applied to the calculation of the surface area of airship envelopes by the use of new values of the constants determined for this purpose. Surface area coefficients were calculated from the actual dimensions, surfaces, and volumes of 52 streamline bodies, which form a series covering the entire range of shapes used in the present aeronautical practice" (p. 1).
Date: February 1922
Creator: Diehl, W. S.
System: The UNT Digital Library
Causes of cracking of ignition cable (open access)

Causes of cracking of ignition cable

From Summary: "The experiments described here show that the cracking at sharp bends, observed in the insulation of internal combustion engine high tension ignition wires after service, is due to a chemical attack upon the rubber by the ozone produced by the electric discharge that takes place at the surface of the cable. This cracking does not occur if the insulating material is not under tension, or if the cable is surrounded by some medium other than air. But it does occur even if the insulation is not subjected to electric stress, provided that the atmosphere near the cable contains ozone. The extent of this cracking varies greatly with the insulating material used. The cracking can be materially reduced by using braided cable and by avoiding sharp bends."
Date: February 1921
Creator: Dempsey, J. B. & Silsbee, F. B.
System: The UNT Digital Library
The Effect of the Nature of Surfaces on Resistance as Tested on Struts (open access)

The Effect of the Nature of Surfaces on Resistance as Tested on Struts

The chief concern was to measure the variations of resistance brought about by the nature of the surface of the struts. The struts were spanned with aviation linen, and then covered with one coat of varnish. The top surface was not perfectly smooth after this treatment, being slightly rough owing to the threads and raised fibers of the fabric. The results of the measurements of the surfaces are shown by the dotted lines of the curves plotted in several figures.
Date: February 1921
Creator: Wieselsberger, G.
System: The UNT Digital Library
Effect of the Reversal of Air Flow Upon the Discharge Coefficient of Durley Orifices (open access)

Effect of the Reversal of Air Flow Upon the Discharge Coefficient of Durley Orifices

Experiments were conducted to obtain information on the relationship between the coefficients for flow in two directions through thin plate orifices at low velocities. The results indicate that the ratio of the orifice discharge coefficient from standard orifice C(sub s)(sup 1) to the discharge coefficient from the reverse flow C(sub s) is always less than unity with increasing ratio of box area to orifice area. Even for areas as low as twenty, the ratios of the coefficients are not much less than unity. It is probable, however, that when the ratio of box area is less than twenty, the ratio of discharge coefficients would be greatly reduced. Specific results are given for the case of an apparatus for the laboratory testing of superchargers.
Date: February 1921
Creator: Ware, Marsden
System: The UNT Digital Library
Tests on an Airplane Model, AEG D I of the Allgemeine Elektricitats Gesellschft, A-G, Airplane Construction Section Conducted at the Gottingen Model Testing Laboratory for Aerodynamics (open access)

Tests on an Airplane Model, AEG D I of the Allgemeine Elektricitats Gesellschft, A-G, Airplane Construction Section Conducted at the Gottingen Model Testing Laboratory for Aerodynamics

"Tests were carried out in the small wind tunnel of the Gottingen establishment on a complete model of the AEG D I airplane. The agreement between the model and the complete airplane applies particularly to the wings, which have ribs cut out of sheet metal and built up in exactly the same manner as in the actual airplane. Various series of tests were carried out with this model in which one or the other of the control surfaces were adjusted to various angles, while the others remained in their neutral positions" (p. 1).
Date: February 1923
Creator: Munk, Max & Molthan, Wilhelm
System: The UNT Digital Library
Model Supports and Their Effects on the Results of Wind Tunnel Tests (open access)

Model Supports and Their Effects on the Results of Wind Tunnel Tests

"The airflow about a model while being tested is often sufficiently affected by the model support to lead to erroneous conclusions unless appropriate corrections are used. In this paper some new material on the subject is presented, together with a review of the airfoil support corrections used in several other laboratories" (p. 1).
Date: February 1923
Creator: Bacon, David L.
System: The UNT Digital Library
Note on the Resistance of Polished Cylinders (and Cylindrical Wires) With Generatrices Perpendicular to the Airstream (open access)

Note on the Resistance of Polished Cylinders (and Cylindrical Wires) With Generatrices Perpendicular to the Airstream

Report presenting a review of currently published documents regarding the resistance of polished cylinders with generators perpendicular to the airstream. The discrepancies between these various studies are pointed out.
Date: February 1921
Creator: Toussaint, A.
System: The UNT Digital Library
Impact Tests for Woods (open access)

Impact Tests for Woods

Although it is well known that the strength of wood depends greatly upon the time the wood is under the load, little consideration has been given to this fact in testing materials for airplanes. Here, results are given of impact tests on clear, straight grained spruce. Transverse tests were conducted for comparison. Both Izod and Charpy impact tests were conducted. Results are given primarily in tabular and graphical form.
Date: February 1922
Creator: unknown
System: The UNT Digital Library
Interference of Multiplane Wings Having Elliptical Lift Distribution (open access)

Interference of Multiplane Wings Having Elliptical Lift Distribution

In calculating the self-induction of a wing surface, elliptical lift distribution is assumed, while in calculating the mutual induction or interference of two wing surfaces, a uniform distribution of the lift along the wing has hitherto been assumed. Whether the results of these calculations are substantially altered by assuming an elliptical lift distribution (which is just as probable as uniform distribution) is examined here.
Date: February 1924
Creator: von Sanden, H.
System: The UNT Digital Library
Induced Drag of Multiplanes (open access)

Induced Drag of Multiplanes

"The most important part of the resistance or drag of a wing system, the induced drag, can be calculated theoretically, when the distribution of lift on the individual wings is known. The calculation is based upon the assumption that the lift on the wings is distributed along the wing in proportion to the ordinates of a semi-ellipse. Formulas and numerical tables are given for calculating the drag. In this connection, the most favorable arrangements of biplanes and triplanes are discussed and the results are further elucidated by means of numerical examples" (p. 1).
Date: February 1924
Creator: Prandtl, L.
System: The UNT Digital Library
Triplane Tests (open access)

Triplane Tests

"These experiments were carried out to determine the aerodynamic characteristics of various triplanes, which differed in the relative positions of the wings and, more especially, in the stagger, and in the shape of the wing sections. The tests were restricted to such dispositions as appeared constructively adapted to the plan form considered. Four different sets of wings were used in these tests, three of which had the same cross-section but differed in aspect ratio and in area" (p. 1).
Date: February 1924
Creator: Wieselsberger, C.
System: The UNT Digital Library
Practical Method for Balancing Airplane Moments (open access)

Practical Method for Balancing Airplane Moments

"The present contribution is the sequel to a paper written by Messrs. R. Fuchs, L. Hopf, and H. Hamburger, and proposes to show that the methods therein contained can be practically utilized in computations. Furthermore, the calculations leading up to the diagram of moments for three airplanes, whose performance in war service gave reason for complaint, are analyzed. Finally, it is shown what conclusions can be drawn from the diagram of moments with regard to the defects in these planes and what steps may be taken to remedy them" (p. 1).
Date: February 1924
Creator: Hamburger, H.
System: The UNT Digital Library
Increasing the Compression Pressure in an Engine by Using a Long Intake Pipe (open access)

Increasing the Compression Pressure in an Engine by Using a Long Intake Pipe

"During some tests of a one-cylinder engine, using gas oil (diesel engine oil, specific gravity 0.86 at 60 F) with solid injection and compression ignition, it was found to be necessary to increase either the jacket water temperature or the compression pressure in order to start the engine. It was found that a sufficient increase in compression pressure could be obtained simply by attaching a long pipe to the inlet flange of the cylinder. However, since no data were available giving the values of the increase in compression pressure that might be expected from such a step-up, an investigation was made covering some engine speeds between 500 r.p.m. and 1800 r.p.m." (p. 1).
Date: February 1924
Creator: Matthews, Robertson & Gardiner, Arthur W.
System: The UNT Digital Library