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Calculation of Centrally Loaded Thin-Walled Columns Above the Buckling Limit

Description: "When thin-walled columns formed from flanged sheet, such as used in airplane construction, are subjected to axial load, their behavior at failure varies according to the slenderness ratio. On long columns the axis deflects laterally while the cross section form is maintained; buckling results. The respective breaking load in the elastic range is computed by Euler's formula and for the plastic range by the Engesser- Karman formula. Its magnitude is essentially dependent upon the length" (p. 1).
Date: April 1945
Creator: Reinitzhuber, F.
Partner: UNT Libraries Government Documents Department

A numerical procedure for designing cascade blades with prescribed velocity distribution in incompressible potential flow

Description: Report presenting a step-by-step numerical procedure based on conformal-mapping theory for the design of a cascade of airfoils with a prescribed dimensionless-velocity distribution in incompressible potential flow. It includes a set of tables to serve as a guide in computation. A comparison of several different types of airfoil design are included to examine the reliability of the procedure.
Date: June 1950
Creator: Hansen, Arthur G. & Yohner, Peggy L.
Partner: UNT Libraries Government Documents Department

Investigation of two-stage counterrotating compressor I : design and over-all performance of transonic first compressor stage

Description: Report presenting a highly loaded transonic rotor which was designed, built, and tested as part of a two-stage counterrotating-compressor research program. The design conditions were chosen to explore the upper limits of loading and Mach number for the transonic unit. The complete rotor design procedure is presented as well as the recorded stall traces and techniques for obtaining the data.
Date: May 22, 1956
Creator: Wilcox, Ward W. & Wright, Linwood C.
Partner: UNT Libraries Government Documents Department

Effectiveness at transonic speeds of flap-type ailerons for several spanwise locations on a 4-percent-thick sweptback-wing-fuselage model with and without tails

Description: Report presenting a transonic investigation in the 16-foot transonic tunnel to determine the effects of spanwise location of a flap-type aileron on the lateral characteristics of a 4-percent-thick sweptback-wing-fuselage model. Results regarding the effect of aileron spanwise position on roll and lift effectiveness, tail effects, and effect of spanwise aileron position on complete model rolling-moment characteristics are provided.
Date: February 26, 1957
Creator: Hieser, Gerald & Whitcomb, Charles F.
Partner: UNT Libraries Government Documents Department

A load factor formula

Description: The ultimate test of a load factor formula is experience. The chief advantages of a semi rational formula over arbitrary factors are that it fairs in between points of experience and it differentiates according to variables within a type. Structural failure of an airplane apparently safe according to the formula would call for a specific change in the formula. The best class of airplanes with which to check a load factor formula seems to be those which have experienced structural failure. Table I comprises a list of the airplanes which have experienced failure in flight traceable to the wing structure. The load factor by formula is observed to be greater than the designed strength in each case, without a single exception. Table II comprises the load factor by formula with the designed strength of a number of well-known service types. The formula indicates that by far the majority of these have ample structural strength. One case considered here in deriving a suitable formula is that of a heavy load carrier of large size and practically no reserve power.
Date: August 1927
Creator: Miller, Roy G.
Partner: UNT Libraries Government Documents Department

Lift, drag, and static longitudinal stability characteristics of four airplane-like configurations at Mach numbers from 3.00 to 6.28

Description: Report presenting lift, drag, and pitching-moment coefficients, lift-drag ratios, and center-of-pressure positions for four airplane-like configurations determined from tests at a range of Mach numbers and angles of attack. The wings and nose shapes were modified for each of the configurations.
Date: April 25, 1955
Creator: Neice, Stanford E.; Wong, Thomas J. & Hermach, Charles A.
Partner: UNT Libraries Government Documents Department

A preliminary investigation of the static stability characteristics of four airplane-like configurations at Mach numbers from 3.00 to 6.28

Description: 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.
Date: March 26, 1956
Creator: Wong, Thomas J. & Gloria, Hermilo R.
Partner: UNT Libraries Government Documents Department

Recent research on the creep of airframe components

Description: Report presenting the results of research on the creep of airframe components at elevated temperatures. Experimental lifetime data from creep tests of stainless-steel plates and aluminum-alloy unstiffened circular cylinders are presented and compared with results predicted from isochronous stress-strain curves.
Date: July 1957
Creator: Mathauser, Eldon E.; Berkovits, Avraham & Stein, Bland A.
Partner: UNT Libraries Government Documents Department

Design and test of mixed-flow impellers 6: performance and parabolic-bladed impeller with shroud redesigned by rapid approximate method

Description: Report presenting a centrifugal impeller with a modified design procedure to reduce the velocity gradients existing along the hub from inlet to outlet. The modified impeller had better performance characteristics than the original at all speeds tested.
Date: September 7, 1955
Creator: Smith, Kenneth J. & Osborn, Walter M.
Partner: UNT Libraries Government Documents Department

Design and test of mixed-flow impellers 1: aerodynamic design procedure

Description: Report presenting the design of a mixed-flow impeller with special emphasis on the reduction or elimination of velocity deceleration along the wetted surfaces, especially the blade suction surface. With the use of a provisional hub-shroud profile, the blade shape at the blade mean height was determined from a prescribed velocity distribution.
Date: September 19, 1952
Creator: Osborn, Walter M. & Hamrick, Joseph T.
Partner: UNT Libraries Government Documents Department

Bibliography and review of information relating to the hydrodynamics of seaplanes

Description: Report presenting a bibliography and review of information related to the hydrodynamics of seaplanes. Characteristics of conventional hulls and floats are discussed to show the effects upon performance of changes in design parameters like dead rise, depth of step, and angle of afterbody keel. Other topics include floats, lateral stabilizers, aerodynamic and propulsive considerations, unconventional configurations, hydrofoils, and piloting and handling.
Date: September 1945
Creator: Benson, James M. & Bidwell, Jerold M.
Partner: UNT Libraries Government Documents Department

Comparison of measured and calculated stresses in built-up beams

Description: Web stresses and flange stresses were measured in three built-up beams: one of constant depth with flanges of constant cross-section, one linearly tapered in depth with flanges of constant cross section, and one linearly tapered in depth with tapered flanges. The measured stresses were compared with the calculated stresses obtained by the methods outlined in order to determine the degree of accuracy that may be expected from the stress analysis formulas. These comparisons indicated that the average measured stresses for all points in the central section of the beams did not exceed the average calculated stresses by more than 5 percent. It also indicated that the difference between average measured flange stresses and average calculated flange stresses on the net area and a fully effective web did not exceed 6.1 percent.
Date: May 1946
Creator: Levin, L. Ross & Nelson, David H.
Partner: UNT Libraries Government Documents Department

Bodies of Revolution for Minimum Drag at High Supersonic Airspeeds

Description: From Summary: "Approximate shapes of nonlifting bodies having minimum pressure foredrag at high supersonic airspeeds are calculated.With the aid of Newton's law of resistance, the investigation is carried out for various combinations of the conditions of given body length, base diameter, surface area, and volume. In general it is found that when body length is fixed, the body has a blunt nose; whereas, when the length is not fixed, the body has a sharp nose."
Date: February 25, 1952
Creator: Eggers, A. J., Jr.; Dennis, David H. & Resnikoff, Meyer M.
Partner: UNT Libraries Government Documents Department

Bodies of revolution having minimum drag at high supersonic airspeeds

Description: Approximate shapes of nonlifting bodies having minimum pressure foredrag at high supersonic airspeeds are calculated. With the aid of Newton's law of resistance, the investigation is carried out for various combinations of the conditions of given body length, base diameter, surface area, and volume. In general, it is found that when body length is fixed, the body has a blunt nose; whereas, when the length is not fixed, the body has a sharp nose. The additional effect of curvature of the flow over the surface is investigated to determine its influence on the shapes for minimum drag. The effect is to increase the bluntness of the shapes in the region of the nose and the curvature in the region downstream of the nose. These shape modifications have, according to calculation, only a slight tendency to reduce drag. Several bodies of revolution of fineness ratios 3 and 5, including the calculated shapes of minimum drag for given length and base diameter and for given base diameter and surface area, were tested at Mach numbers from 2.73 to 6.28. A comparison of theoretical and experimental foredrag coefficients indicates that the calculated minimum-drag bodies are reasonable approximations to the correct shape.
Date: December 14, 1955
Creator: Eggers, A. J., Jr.; Resnikoff, Meyer M. & Dennis, David H.
Partner: UNT Libraries Government Documents Department

Bodies of revolution having minimum drag at high supersonic airspeeds

Description: Report presenting calculations of approximate shapes of nonlifting bodies having minimum pressure foredrag at higher supersonic airspeeds. The investigation is carried out for various combinations of the conditions of given body length, base diameter, surface area, and volume.
Date: February 1956
Creator: Eggers, A. J., Jr.; Resnikoff, Meyer M. & Dennis, David H.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of an NACA low-drag tapered wing with straight trailing edge and simple split flaps, special report

Description: Report discusses the results of an investigation to determine the effect of the split flaps on the aerodynamic characteristics of the tapered wing. The results indicated that values of maximum lift coefficient obtained from the NACA low-drag sections are comparable to values obtained on tapered wings with conventional sections. The addition of split flaps did not appreciably alter the pattern of the stall.
Date: December 1941
Creator: Muse, Thomas C. & Neely, Robert H.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of the lift characteristics of an NACA 27-212 airfoil equipped with two types of flap, special report

Description: From Summary: "An investigation has been made in the NACA 7- by 10-foot wind tunnel of a large chord NACA 27-212 airfoil with a 20% chord split flap and with two arrangements of a 25.66% chord slotted flap to determine the section lift characteristics as affected by flap deflection for the split flap and as affected by flap deflection, flap position, and slot shape for the slotted flap. For the two arrangements of the slotted flap, the flap positions for maximum section lift are given. Comparable data on the NACA 23012 airfoil equipped with similar flaps are also given."
Date: September 1940
Creator: Swanson, Robert S. & Schuldenfrei, Marvin J.
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests of the NACA 45-125 airfoil: a thick airfoil for high-speed airplanes

Description: Report discussing an investigation of the pressure distribution, profile drag, and location of transition for a NACA 45-125 airfoil for the purpose of aiding in the development of a thick wing for high-speed airplanes. The critical speed, pressure distribution, and drag of the airfoil are detailed.
Date: February 1940
Creator: Delano, James B.
Partner: UNT Libraries Government Documents Department

A Theoretical Investigation of the Drag of Generalized Aircraft Configurations in Supersonic Flow

Description: It seems possible that, in supersonic flight, unconventional arrangements of wings and bodies may offer advantages in the form of drag reduction. It is the purpose of this report to consider the methods for determining the pressure drag for such unconventional configurations, and to consider a few of the possibilities for drag reduction in highly idealized aircraft. The idealized aircraft are defined by distributions of lift and volume in three-dimensional space, and Hayes' method of drag evaluation, which is well adapted to such problems, is the fundamental tool employed. Other methods of drag evaluation are considered also wherever they appear to offer amplifications. The basic singularities such as sources, dipoles, lifting elements and volume elements are discussed, and some of the useful inter-relations between these elements are presented. Hayes' method of drag evaluation is derived in detail starting with the general momentum theorem. In going from planar systems to spatial systems certain new problems arise. For example, interference between lift and thickness distributions generally appears, and such effects are used to explain the difference between the non-zero wave drag of Sears-Haack bodies and the zero wave drag of Ferrari's ring wing plus central body. Another new feature of the spatial systems is that optimum configurations generally are not unique, there being an infinite family of lift or thickness distributions producing the same minimum drag. However it is shown that all members of an optimum family produce the same flow field in a certain region external to the singularity distribution. Other results of the study indicate that certain spatial distributions may produce materially less wave drag and vortex drag than comparable planar systems. It is not at all certain that such advantages can be realized in practical aircraft designs, but further investigation seems to be warranted.
Date: January 1957
Creator: Graham, E. W.; Lagerstrom, P. A.; Licher, R. M. & Beane, B. J.
Partner: UNT Libraries Government Documents Department

Soaring flight and the Rhön contests

Description: Explanation of soaring flight. Static and dynamic soaring flight. Results of the Rhon contest. Description of the most important gliders. Notes on Soaring Flight Contests in France and England.
Date: January 1923
Creator: Hoff, Wilhelm
Partner: UNT Libraries Government Documents Department

Nitrided-steel piston rings for engines of high specific power

Description: Report presenting testing of several designs of nitrided-steel piston rings under variable conditions of output. Testing indicated the importance of good surface finish and conformity of the ring to the bore. Results regarding temperature tests, single-cylinder-engine tests, and multicylinder-engine tests are provided.
Date: April 1944
Creator: Collins, John H., Jr.; Bisson, Edmond E. & Schmiedlin, Ralph F.
Partner: UNT Libraries Government Documents Department

Pressure Distribution on the Fuselage of a Midwing Airplane Model at High Speeds

Description: Report presenting the pressure distribution on the fuselage of a midwing airplane model measured in the 8-foot high-speed wind tunnel at a range of speeds and lift coefficients. The primary purpose of the investigation was to provide data showing the air pressures on various parts of the fuselage for use in structural design.
Date: February 1943
Creator: Delano, James B.
Partner: UNT Libraries Government Documents Department

Minimum wave drag for arbitrary arrangements of wings and bodies

Description: "Studies of various arrangements of wings and bodies designed to provide favorable wave interference at supersonic speeds lead to the problem of determining the minimum possible valve of the wave resistance obtainable by any disposition of the elements of an aircraft within a definitely prescribed region. Under the assumptions that the total lift and the total volume of the aircraft are given, conditions that must be satisfied if the drag is to be a minimum are found. The report concludes with a discussion of recent developments of the theory which lead to an improved understanding of the drag associated with the production of lift" (p. 1).
Date: February 1956
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department