Aerodynamic Characteristics of a 4-Engine Monoplane Showing Comparison of Air-Cooled and Liquid-Cooled Engine Installations (open access)

Aerodynamic Characteristics of a 4-Engine Monoplane Showing Comparison of Air-Cooled and Liquid-Cooled Engine Installations

From Introduction: "An investigation has been conducted in the N.A.C.A. full-scale wind tunnel to determine the aerodynamic characteristics of a 1/4-scale model of a 4-engine monoplane when equipped with comparable air-cooled engine and liquid-cooled engine installations. The air-cooled engine installation consisted of nacelles equipped with N..A.C.A. cowlings and oil coolers located in the leading edge of the wing."
Date: July 1939
Creator: Silverstein, Abe & Wilson, Herbert A., Jr.
Object Type: Report
System: The UNT Digital Library
Design of Centrifugal Impeller Blades (open access)

Design of Centrifugal Impeller Blades

This paper restricts itself to radial impellers with cylindrical blades since, as Prasil has shown, the flow about an arbitrarily curved surface of revolution may be reduced to this normal form we have chosen by a relatively simple conformal transformation. This method starts from the simple hypotheses of the older centrifugal impeller theory by first assuming an impeller with an infinite number of blades. How the flow is then modified is then investigated.
Date: July 1939
Creator: Betz, A. & FlĂĽgge-Lotz, I.
Object Type: Report
System: The UNT Digital Library
The Effect of the Masses of the Controls on the Longitudinal Stability With Free Elevator Part 1 (open access)

The Effect of the Masses of the Controls on the Longitudinal Stability With Free Elevator Part 1

In the present report, aerodynamic relations under the effect of the weight moments are investigated, and an example given of the computation of the stability for a practical case. Later, the effects of the masses of the controls on the dynamic longitudinal stability will be considered.
Date: July 1939
Creator: Schmidt, Rudolf
Object Type: Report
System: The UNT Digital Library
The effects of partial-span slotted flaps on the aerodynamic characteristics of a rectangular and a tapered N.A.C.A. 23012 wing (open access)

The effects of partial-span slotted flaps on the aerodynamic characteristics of a rectangular and a tapered N.A.C.A. 23012 wing

An investigation was made in the N.A.C.A. 7- by 10-foot wind tunnel to determine the aerodynamic characteristics of tapered and rectangular wings with partial-span slotted flaps. Two N.A.C.A. 23012 airfoils equipped with center-section and tip-section flaps were tested. The results showed that the changes in lift and drag due to changes in flap span for both rectangular and tapered wings having partial-span slotted flaps were similar to those for corresponding wings having partial-span split or plain flaps. For the two wings tested, higher values of maximum lift were obtained with center-section slotted flaps than with tip-section slotted flaps of the same size. The highest values of lift-drag ratio at maximum lift for the rectangular wing were obtained with center-section flaps and, for the tapered wing, with tip-section flaps. Center-section flaps on the tapered wing gave higher values of drag at maximum lift than tip-section flaps; no great difference in drag at maximum lift was apparent for either center-section or tip-section slotted flaps on the rectangular wing.
Date: July 1939
Creator: House, Rufus O.
Object Type: Report
System: The UNT Digital Library
Hydrodynamic and aerodynamic tests of a family of models of seaplane floats with varying angles of dead rise: N.A.C.A. Models 57-A, 57-B, and 57-C (open access)

Hydrodynamic and aerodynamic tests of a family of models of seaplane floats with varying angles of dead rise: N.A.C.A. Models 57-A, 57-B, and 57-C

Three models of V-bottom floats for twin-float seaplanes (N.A.C.A. models 57-A, 57-B, and 57-C) having angles of dead rise of 20 degrees, 25 degrees, and thirty degrees, respectively, were tested in the N.A.C.A. tank and in the N.A.C.A. 7- by 10-foot wind tunnel. Within the range investigated, the effect of angle of dead rise on water resistance was found to be negligible at speeds up to and including the hump speed, and water resistance was found to increase with angle of dead rise at planing speeds. The height of the spray at the hump speed decreased with increase in angle of dead rise and the aerodynamic drag increased with dead rise. Lengthening the forebody of model 57-B decreased the water resistance and the spray at speeds below the hump speed. Spray strips provided an effective means for the control of spray with the straight V sections used in the series but considerably increased the aerodynamic drag. Charts for the determination of the water resistance and the static properties of the model with 25 degrees dead rise and for the aerodynamic drag of all the models are included for use in design.
Date: July 1939
Creator: Parkinson, John B.; Olson, Roland E. & House, Rufus O.
Object Type: Report
System: The UNT Digital Library
Hydrodynamic and Aerodynamic Tests of a Family of Models of Seaplane Floats With Varying Angles of Dead Rise: N.A.C.A. Models 57-A, 57-B, and 57-C (open access)

Hydrodynamic and Aerodynamic Tests of a Family of Models of Seaplane Floats With Varying Angles of Dead Rise: N.A.C.A. Models 57-A, 57-B, and 57-C

Report presenting testing of three models of V-bottom floats for twin-float seaplanes with varying angles of dead rise were tested in a tank and a wind tunnel. Results regarding the effect of angle of dead rise, height and amount of spray at hump speed, aerodynamic drag, effect of cross-sectional shape and load coefficients, and spray strips are provided.
Date: July 1939
Creator: Parkinson, John B.; Olson, Roland E. & House, Rufus O.
Object Type: Report
System: The UNT Digital Library
Investigations and Experiments in the Guidonia Wind Tunnel (open access)

Investigations and Experiments in the Guidonia Wind Tunnel

This paper is a presentation of the experiments and equipment used in investigations at the Guidonia wind tunnel. The equipment consisted of: a number of subsonic and supersonic cones, an aerodynamic balance, and optical instruments operating on the Schlieren and interferometer principle.
Date: July 1939
Creator: Ferri, Antonio
Object Type: Report
System: The UNT Digital Library
A Method of Estimating the Critical Buckling Load for Structural Members (open access)

A Method of Estimating the Critical Buckling Load for Structural Members

"The relations between load on the structure and rotation of a joint can be used to estimate the lowest critical load after the equation for neutral stability has been tested for three assumed critical loads, each of which is less than the lowest critical load. The solutions of six simple problems are included to illustrate the application of the method of estimating critical loads and to reveal certain characteristics of the method that should be known by the practical engineer using it. Four of these problems are concerned with members that lie in the elastic, or long-column, range. The other two problems are concerned with members that lie in the short-column range" (p. 1).
Date: July 1939
Creator: Lundquist, Eugene E.
Object Type: Report
System: The UNT Digital Library
Monthly Report of the Attorney General of the State of Texas, Volume 1, Number 5, June 1939 (open access)

Monthly Report of the Attorney General of the State of Texas, Volume 1, Number 5, June 1939

Monthly report documenting orders, opinions, and other legal statements issued by the Office of the Attorney General in Texas.
Date: July 1939
Creator: Texas. Attorney-General's Office.
Object Type: Report
System: The Portal to Texas History
Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report (open access)

Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report

"Two cowling systems intended to reduce the drag and improve the low-speed cooling characteristics of conventional radial engine cowlings were tested in model form to determine the practicability of the methods. One cowling included a blower mounted on the rear face of a large propeller spinner which drew cooling air in through side entrance ducts located behind the equivalent engine orifice plate. The air was passed through the equivalent engine orifice plate from rear to front and out through a slot between the spinner and the engine plate" (p. 1).
Date: July 1939
Creator: Biermann, David & Valentine, E. Floyd
Object Type: Report
System: The UNT Digital Library
Reservoir Characteristics of the Eunice Oil Field, Lea County, New Mexico (open access)

Reservoir Characteristics of the Eunice Oil Field, Lea County, New Mexico

Report issued by the U.S. Bureau of Mines on the oil and gas production of the Eunice oil field in southeastern New Mexico. Properties of the oil field, and analysis of the oil and gas produced are presented. This report includes tables, maps, illustrations, and photographs.
Date: July 1939
Creator: Anderson, C. C.; Hinson, H. H. & Schroeder, H. J.
Object Type: Report
System: The UNT Digital Library
Resistance of transparent plastics to impact (open access)

Resistance of transparent plastics to impact

From Summary: "The problem of developing a windshield for aircraft which will withstand the effect of bird impacts during flight is a difficult one, as an estimate of the striking energy will indicate. If the average speed of the airplane is considered to be about 200 miles per hour and that of the bird about 70 miles per hour, the speed of the bird relative to the airplane may be as great as 400 feet per second. If a 4-pound bird is involved, a maximum impact energy of approximately 10,000 foot-pounds must be dissipated. To obtain this energy in a drop test in the Washington Monument, it would be necessary to drop a 20-pound weight down the 500-foot shaft. For both theoretical and practical reasons, it is necessary to keep the mass and speed more nearly like those to be encountered. However, to get an impact of about 10,000 foot-pounds with a 4-pound falling body, it would be necessary to drop it from a height of approximately one-half mile, neglecting air resistance. These facts will indicate some of the experimental obstacles in the way of simulating bird impacts against aircraft windshields."
Date: July 1939
Creator: Axilrod, Benjamin M. & Kline, Gordon M.
Object Type: Report
System: The UNT Digital Library
Strawberry Clover. (open access)

Strawberry Clover.

Describes the growth of strawberry clover in fields, its benefits and tolerance, and steps for planting, cultivating, and seed production.
Date: July 1939
Creator: Hollowell, E. A. (Eugene Amos)
Object Type: Book
System: The UNT Digital Library
Texas Attorney General Opinion: O-595 (open access)

Texas Attorney General Opinion: O-595

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification: Does the County Commissioners' court of Galveston County, Texas have authority to employ life-guards for the Galveston Beach and pay them for their services out of county funds?
Date: July 21, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-681 (open access)

Texas Attorney General Opinion: O-681

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification: Under the facts set forth, should the fine and costs be turned into the county treasurer for the benefit of the Salary Fund?
Date: July 12, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-863 (open access)

Texas Attorney General Opinion: O-863

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification: Contract of county hospital for laundry work.
Date: July 6, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-883 (open access)

Texas Attorney General Opinion: O-883

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification: Maximum tax rate under charter of City of Terrell's authority to pledge net profits of municipal light plant, together with ad valorem taxes to service general obligation bonds of the city; authority under the city charter to levy a tax other than that provided for in Sections 17, 18, 21, and 22, for the payment of street improvement bonds.
Date: July 21, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-909 (open access)

Texas Attorney General Opinion: O-909

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification: Authority of a Commissioners’ Court to enter into an agreement either in or out of court to accept refunding bonds bearing a lower rate of interest in lieu of bonds held in the permanent school fund of the county; and to accept a discount of past due interest accrued thereon.
Date: July 14, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-912 (open access)

Texas Attorney General Opinion: O-912

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification; Art. 1415a, R.C.S., which requires commercial colleges organized after its passage in 1929 to give a bond, and exempting from its provisions all commercial colleges then in existence, its unconstitutional.
Date: July 13, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-915 (open access)

Texas Attorney General Opinion: O-915

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification; What are the proper steps for a county to take at this date of its fiscal year if it has erroneously exercised its option on a salary basis under the provisions of Art. 3912, V. A. C. S. by placing the precinct officers of one precinct on a salary basis?
Date: July 3, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-971 (open access)

Texas Attorney General Opinion: O-971

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification; Whether complaint may be filedin Travis County covering an offense charged for receiving stolen property from the State and comitted in county other than Travis County.
Date: July 7, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-1054 (open access)

Texas Attorney General Opinion: O-1054

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification; Whether a county can sell at a discount State Warrants issued to augment the Officers' Salary Fund.
Date: July 5, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-1069 (open access)

Texas Attorney General Opinion: O-1069

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification; Can expenditures made under authoirty given to the Commissioners' Court by Article 6830 be deducted from the proceeds of a tax levied under authority given to the Commissioners' Court by Article 6830 be deducted from the proceeds of a tax levied under authority granted under Article VIII, Section 9, of the Constitution?
Date: July 6, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: O-1194 (open access)

Texas Attorney General Opinion: O-1194

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Gerald Mann, regarding a legal question submitted for clarification;Applicability of the statute of limitations to made payable to John Tarlenton Agricultural College ot the Board of Directors thereof.
Date: July 27, 1939
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History