Absolute Coefficients and the Graphical Representation of Aerofoil Characteristics (open access)

Absolute Coefficients and the Graphical Representation of Aerofoil Characteristics

It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil.
Date: June 1921
Creator: Munk, Max
System: The UNT Digital Library
Acoustical Treatment for the NACA 8- by 6-Foot Supersonic Propulsion Wind Tunnel (open access)

Acoustical Treatment for the NACA 8- by 6-Foot Supersonic Propulsion Wind Tunnel

"This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory" (p. 1).
Date: June 1955
Creator: Beranek, Leo L.; Labate, Samuel & Ingard, Uno
System: The UNT Digital Library
Adaptor for Measuring Principal Strains With Tuckerman Strain Gage (open access)

Adaptor for Measuring Principal Strains With Tuckerman Strain Gage

Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.
Date: June 1943
Creator: McPherson, A. E.
System: The UNT Digital Library
Aerodynamic Characteristics of a Number of Modified NACA Four-Digit-Series Airfoil Sections (open access)

Aerodynamic Characteristics of a Number of Modified NACA Four-Digit-Series Airfoil Sections

Report presenting theoretical pressure distributions and experimental aerodynamic characteristics at low speeds for a group of NACA four-digit series airfoil sections. Results regarding lift, drag, and pitching moment are provided.
Date: June 1948
Creator: Loftin, Laurence K., Jr. & Cohen, Kenneth S.
System: The UNT Digital Library
Aerodynamic Characteristics of a Refined Deep-Step Planing-Tail Flying-Boat Hull with Various Forebody and Afterbody Shapes (open access)

Aerodynamic Characteristics of a Refined Deep-Step Planing-Tail Flying-Boat Hull with Various Forebody and Afterbody Shapes

From Introduction: "The results of one phase of this investigation, presented in reference 1, have indicated that hull drag can be reduced without causing large changes in aerodynamic stability and hydrodynamic performance by the use of high length-beam ratios. Another phase of the investigation, reference 2, indicated that hulls of the deep-step planning-tail type have much lower air drag than the conventional type of hull and about the same aerodynamic stability; tank tests, reference 3, have indicated that this type of hull also has hydrodynamic performance equal to and in some respects superior to the conventional type of hull. Unpublished tank tests have indicated that the hull models presented in the present paper (with the possible exception of the forebody alone for which data are not available) will have acceptable hydrodynamic performance."
Date: June 1952
Creator: Riebe, John M. & Naeseth, Rodger L.
System: The UNT Digital Library
The Aerodynamic Design of High Mach Number Nozzles Utilizing Axisymmetric Flow with Application to a Nozzle of Square Test Section (open access)

The Aerodynamic Design of High Mach Number Nozzles Utilizing Axisymmetric Flow with Application to a Nozzle of Square Test Section

From Introduction: "A method for the design of three-dimensional nozzles based on axi-symmetric flow is presented in this paper. The design method presented in this paper is general; however, as an illustrative example of the design of a Mach number 10 nozzle with square test section is included."
Date: June 1952
Creator: Beckwith, Ivan E.; Ridyard, Herbert W. & Cromer, Nancy
System: The UNT Digital Library
Aerodynamic investigation of a four-blade propeller operating through an angle-of-attack range from 0 to 180 degrees (open access)

Aerodynamic investigation of a four-blade propeller operating through an angle-of-attack range from 0 to 180 degrees

Report presenting an investigation of the aerodynamic characteristics of a four-blade rigid model propeller in the full-scale tunnel for a range of angles of attack, blade angles, and advance ratio. It included a preliminary explanation of vertical descent and a comparison with theory. Results regarding the static thrust and forward flight are provided.
Date: June 1954
Creator: McLemore, H. Clyde & Cannon, Michael D.
System: The UNT Digital Library
Aerodynamic loads on a leading-edge flap and a leading-edge slat on the NACA 64A010 airfoil section (open access)

Aerodynamic loads on a leading-edge flap and a leading-edge slat on the NACA 64A010 airfoil section

From Summary: "The present report presents the chordwise distributions of pressure measured concurrently with the force and moment data of NACA TN 3007."
Date: June 1954
Creator: Kelly, John A. & McCullough, George B.
System: The UNT Digital Library
Aerodynamic Properties of Cruciform-Wing and Body Combinations at Subsonic, Transonic, and Supersonic Speeds (open access)

Aerodynamic Properties of Cruciform-Wing and Body Combinations at Subsonic, Transonic, and Supersonic Speeds

From Introduction: "Although the aerodynamic characteristics of the components of such configurations may be well known, the mutual interference resulting from combining the wings, as well as the wings and body, may be so great that is desirable to study the aerodynamic properties of the complete configurations. Two methods of handling this problem are presented in this report. The first method is essentially an extension of the theory for slender wing-body combinations of reference 1 to determine the load distribution, forces, and moments exerted on slender cruciform-wing and body combinations inclined simultaneously at small angles in pitch and yaw. "
Date: June 1949
Creator: Spreiter, John R.
System: The UNT Digital Library
Aerodynamic tests of a low aspect ratio tapered wing with various flaps, for use on tailless airplanes (open access)

Aerodynamic tests of a low aspect ratio tapered wing with various flaps, for use on tailless airplanes

From Introduction: "The tests described in this report are the first in an investigation by N.A.C.A. of the aerodynamic characteristics of possible tailless arrangements. The investigations will be extended to include whatever range is through most desirable and may include, among other things, variations in aspect ratio, taper, sweepback, washout, air-foil section, dihedral, and also control flaps or other control devices of different forms and proportions."
Date: June 1933
Creator: Weick, Fred E. & Sanders, Robert
System: The UNT Digital Library
Aeronautical Instruments (open access)

Aeronautical Instruments

Note presenting a number of instruments that can assist pilots with observing the position of the airplane. Some of the instruments include an inclinometer with stationary system of reference and an inclinometer with moving axes.
Date: June 1923
Creator: Bennewitz, Kurt
System: The UNT Digital Library
Airfoil in Sinusoidal Motion in a Pulsating Stream (open access)

Airfoil in Sinusoidal Motion in a Pulsating Stream

"In the present paper, under the same lineaeizing assumptions as are made in the derivation in reference 1 but with the explicit consideration and simplification of the form of the wake extending from the rear of the airfoil, the methods of Theodorsen (reference 2) have been extended to obtain the forces on the airfoil not only at a fixed angle of attack but also in arbitrary motion" (p. 1).
Date: June 1947
Creator: Greenberg, J. Mayo
System: The UNT Digital Library
Airplane Balance (open access)

Airplane Balance

The authors argue that the center of gravity has a preponderating influence on the longitudinal stability of an airplane in flight, but that manufacturers, although aware of this influence, are still content to apply empirical rules to the balancing of their airplanes instead of conducting wind tunnel tests. The author examines the following points: 1) longitudinal stability, in flight, of a glider with coinciding centers; 2) the influence exercised on the stability of flight by the position of the axis of thrust with respect to the center of gravity and the whole of the glider; 3) the stability on the ground before taking off, and the influence of the position of the landing gear. 4) the influence of the elements of the glider on the balance, the possibility of sometimes correcting defective balance, and the valuable information given on this point by wind tunnel tests; 5) and a brief examination of the equilibrium of power in horizontal flight, where the conditions of stability peculiar to this kind of flight are added to previously existing conditions of the stability of the glider, and interfere in fixing the safety limits of certain evolutions.
Date: June 1921
Creator: Huguet, L.
System: The UNT Digital Library
Analogue-computer simulation of an autopilot servo system having nonlinear response characteristics (open access)

Analogue-computer simulation of an autopilot servo system having nonlinear response characteristics

From Introduction: "The servo system considered in this report is in the latter category, due mainly to the fact its amplifier tends to saturate. An investigation of the longitudinal dynamic response of the stabilized airplane was made and the results were reported in reference 1. In this investigation it was found that when restricted to linear methods of analysis the performance of the autopilot-aircraft combination could be predicted for only the small range of operation where the elements of the autopilot operated within their linear range."
Date: June 1952
Creator: Jones, Arthur L. & White, John S.
System: The UNT Digital Library
Analysis and Preliminary Design of an Optical Instrument for the Measurement of Drop Size and Free-Water Content of Clouds (open access)

Analysis and Preliminary Design of an Optical Instrument for the Measurement of Drop Size and Free-Water Content of Clouds

From Summary: "This paper describes a method for the determination of drop size and free water in clouds, based on the interpretation of an artificially created rainbow. Details of the design and operation of an optical instrument employing this method are presented."
Date: June 1948
Creator: Malkus, Willem V. R.; Bishop, Richard H. & Briggs, Robert O.
System: The UNT Digital Library
Analysis of Flight-Performance Measurements on a Twisted, Plywood-Covered Helicopter Rotor in Various Flight Conditions (open access)

Analysis of Flight-Performance Measurements on a Twisted, Plywood-Covered Helicopter Rotor in Various Flight Conditions

From Introduction: "In references 1, 2, and 3, flight measurements of the performance of a conventional, single-rotor helicopter equipped with its production fabric-covered main rotor blades are presented."
Date: June 1948
Creator: Gustafson, F. B. & Gessow, Alfred
System: The UNT Digital Library
An Analysis of Supersonic Flow in the Region of the Leading Edge of Curved Airfoils, Including Charts for Determining Surface-Pressure Gradient and Shock-Wave Curvature (open access)

An Analysis of Supersonic Flow in the Region of the Leading Edge of Curved Airfoils, Including Charts for Determining Surface-Pressure Gradient and Shock-Wave Curvature

Note presenting an investigation of the inviscid flow in the region of the leading edge of curved airfoils with attached shock waves. Tables and charts are presented for determining the surface-pressure gradient and the shock-wave curvature in supersonic flow of an ideal diatomic gas. An approximate procedure for determining the flow field a short distance downstream of the leading edge is also presented.
Date: June 1952
Creator: Kraus, Samuel
System: The UNT Digital Library
An Analysis of the Transition of a Helicopter From Hovering to Steady Autorotative Vertical Descent (open access)

An Analysis of the Transition of a Helicopter From Hovering to Steady Autorotative Vertical Descent

"This report is the second phase of a broad program of study of the transient motions of helicopters in autorotative flight. The first phase (reference 1) dealt with the steady-state condition of autorotative vertical descent. This report is concerned with the the transition from the steady condition of hovering to the steady autorotative descent" (p. 1).
Date: June 1949
Creator: Nikolsky, A. A. & Seckel, Edward
System: The UNT Digital Library
An Analysis of the Variation With Altitude of Effective Gust Velocity in Convective-Type Clouds (open access)

An Analysis of the Variation With Altitude of Effective Gust Velocity in Convective-Type Clouds

From Introduction: "In the present paper, the variation of effective gust velocity in convective-type clouds with altitude is investigated. Data obtained during 1941 and 1942 at altitudes up to 34,000 feet and data obtained more recently from the Thunderstorm Project (reference 5) at altitudes up to 26,000 feet are utilized for this purpose. Consideration is given in analyzing the results both to data for the range
Date: June 1948
Creator: Tolefson, H. B.
System: The UNT Digital Library
An analytical investigation of airplane spin-recovery motion by use of rotary-balance aerodynamic data (open access)

An analytical investigation of airplane spin-recovery motion by use of rotary-balance aerodynamic data

From Introduction: "Many investigations have been made in the Langley 20-foot free-spinning tunnel in which the natures of airplane spins and recoveries have been determined experimentally with dynamically scaled-down models. The results of some of these investigations are presented in references 1 to 5."
Date: June 1954
Creator: Scher, Stanley H.
System: The UNT Digital Library
Analytical Method for Determining Transmission and Absorption of Time-Dependent Radiation Through Thick Absorbers 3: Absorber With Radioactive Daughter Products (open access)

Analytical Method for Determining Transmission and Absorption of Time-Dependent Radiation Through Thick Absorbers 3: Absorber With Radioactive Daughter Products

Report presenting a theoretical treatment of absorption problems that considers the following cases: radiation is normal to an absorber with plane parallel surfaces, radiations are of several polyenergetic types, induced radioactive isotopes decay to stable atoms in multistep decay processes, and radiations from the absorber affect the time-dependency of the source activity. Radiation from intermediate isotopes can become more dangerous than the original activity, so the entire range of radiations must be accounted for.
Date: June 1950
Creator: Allen, G.
System: The UNT Digital Library
An Analytical Study of the Steady Vertical Descent in Autorotation of Single-Rotor Helicopters (open access)

An Analytical Study of the Steady Vertical Descent in Autorotation of Single-Rotor Helicopters

"This report is the result of the first part of a broad program to analyze the transient motions of a helicopter, which occur in the various phases of flight following power failure" (p. 1).
Date: June 1949
Creator: Nikolsky, A. A. & Seckel, Edward
System: The UNT Digital Library
Applicability of the hypersonic similarity rule to pressure distributions which include the effects of rotation for bodies of revolution at zero angle of attack (open access)

Applicability of the hypersonic similarity rule to pressure distributions which include the effects of rotation for bodies of revolution at zero angle of attack

The analysis of Technical Note 2250, 1950, is extended to include the effects of flow rotation. It is found that the theoretical pressure distributions over drive cylinders can be related by the hypersonic similarity rule with sufficient accuracy for most engineering purposes. The error introduced into pressure distributions and drag effective cylinders by ignoring the rotation term in the characteristic equations is investigated.
Date: June 1951
Creator: Rossow, Vernon J.
System: The UNT Digital Library
Application of Scattering Theory to the Measurement of Turbulent Density Fluctuations by an Optical Method (open access)

Application of Scattering Theory to the Measurement of Turbulent Density Fluctuations by an Optical Method

"An analysis shows that the scattering of unpolarized plane light waves which penetrate turbulent, transparent gases provides a measure of the average integral scale and intensity of the turbulent density fluctuations. The analysis is based upon the scattering coefficient deduced by Booker and Gordon and, thus, assumes isotropic fluctuations having an exponentially decaying (Markoffian) correlation function. Photometric data taken through turbulent boundary layers in air are found to conform functionally with the analytical prediction" (p. 1).
Date: June 1956
Creator: Stine, Howard A. & Winovich, Warren
System: The UNT Digital Library