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The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas (open access)

The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

"An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy fuel Specification No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene" (p. 1).
Date: 1943
Creator: Gerrish, Harold C. & Meem, J. Lawrence, Jr.
System: The UNT Digital Library
Performance of B. M. W. 185-Horsepower Airplane Engine (open access)

Performance of B. M. W. 185-Horsepower Airplane Engine

"This report deals with the results of a test made upon a B. M. W. Engine in the altitude chamber of the Bureau of Standards, where controlled conditions of temperature and pressure can be made to simulate those of the desired altitude. A remarkably low value of fuel consumption - 041 per B. H. P. hour - is obtained at 1,200 revolutions per minute at an air density of 0.064 pound per cubic foot and a brake thermal efficiency of 33 per cent and an indicated efficiency of 37 per cent at the above speed and density. In spite of the fact that the carburetor adjustment does not permit the air-fuel ratio of maximum economy to be obtained at air densities lower than 0.064, the economy is superior to most engines tested thus far, even at a density lower than 0.064, the economies superior to most engines tested thus far, even at a density (0.03) corresponding to an altitude of 25,000 feet" (p. 1).
Date: 1922
Creator: Sparrow, S. W.
System: The UNT Digital Library
Stability of the Parachute and Helicopter (open access)

Stability of the Parachute and Helicopter

This report deals with an extension of the theory of stability in oscillation to the case of aircraft following a vertical trajectory, and particularly to the oscillations of parachutes.
Date: 1920
Creator: Bateman, H.
System: The UNT Digital Library
Supplies and Production of Aircraft Woods (open access)

Supplies and Production of Aircraft Woods

The purpose of this report is to present in brief form such information as is available regarding the supplies of the kinds of wood that have been used or seem likely to become important in the construction of airplanes, and the amount of lumber of each species normally put on the market each year. A general statement is given of the uses to which each kind of wood is or may be put.
Date: 1920
Creator: Sparhawk, W. N.
System: The UNT Digital Library
The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates (open access)

The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates

"The theory of Lagrangian multipliers is applied to the problem of finding both upper and lower limits to the true compressive buckling stress of a clamped rectangular plate. The upper and lower limits thus bracket the truss, which cannot be exactly found by the differential-equation approach. The procedure for obtaining the upper limit, which is believed to be new, presents certain advantages over the classical Raleigh-Rite method of finding upper limits" (p. 1).
Date: 1946
Creator: Budiansky, Bernard & Hu, Pai C.
System: The UNT Digital Library
The Kiln Drying of Wood for Airplanes (open access)

The Kiln Drying of Wood for Airplanes

This report is descriptive of various methods used in the kiln drying of woods for airplanes and gives the results of physical tests on different types of woods after being dried by the various kiln-drying methods.
Date: 1919
Creator: Tiemann, Harry D.
System: The UNT Digital Library
A Low-Speed Experimental Investigation of the Effect of a Sandpaper Type of Roughness on Boundary-Layer Transition (open access)

A Low-Speed Experimental Investigation of the Effect of a Sandpaper Type of Roughness on Boundary-Layer Transition

Report describing the effects of an area of roughness on the velocity and turbulence measurements of an airfoil. It details the effects of the size, location, and height of the roughness on the Reynolds number. From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition."
Date: 1958
Creator: Horton, Elmer A. & von Doenhoff, Albert E.
System: The UNT Digital Library
The effect of cowling on cylinder temperatures and performance of a Wright J-5 engine (open access)

The effect of cowling on cylinder temperatures and performance of a Wright J-5 engine

This report presents the results of tests conducted to determine the effect of different amounts and kinds of cowling on the performance and cylinder temperatures of a standard Wright J-5 engine. These tests were conducted in conjunction with drag and propeller tests in which the same cowlings were used. Four different cowlings were investigated varying from the one extreme of no cowling on the engine to the other extreme of the engine completely cowled and the cooling air flowing inside the cowling through an opening in the nose and out through an annular opening at the rear of the engine. Each cowling was tested at air speeds of approximately 60, 80, and 100 miles per hour.
Date: May 2, 1929
Creator: Schey, Oscar W. & Biermann, Arnold E.
System: The UNT Digital Library
Preliminary Report on the Problem of the Atmosphere in Relation to Aeronautics (open access)

Preliminary Report on the Problem of the Atmosphere in Relation to Aeronautics

A report to the Weather Bureau, Washington DC, from the chairman of the Subcommittee on the Atmosphere in Relation to Aeronautics describing the activities accomplished and the proposal of work to be undertaken by the subcommittee.
Date: November 9, 1915
Creator: Marvin, Charles F.
System: The UNT Digital Library
A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blend (open access)

A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blend

"The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends" (p. 1).
Date: 1943
Creator: Sanders, Newell D.
System: The UNT Digital Library
Diaphragms for Aeronautic Instruments (open access)

Diaphragms for Aeronautic Instruments

This investigation was carried out at the request of the National Advisory Committee for Aeronautics and comprises an outline of historical developments and theoretical principles, together with a discussion of expedients for making the most effective use of existing diaphragms actuated by the hydrostatic pressure form an essential element of a great variety instruments for aeronautic and other technical purposes. The various physical data needed as a foundation for rational methods of diaphragm design have not, however, been available hitherto except in the most fragmentary form.
Date: 1923
Creator: Hersey, M. D.
System: The UNT Digital Library
A Comparison of Theory and Experiment for High-Speed Free-Molecule Flow (open access)

A Comparison of Theory and Experiment for High-Speed Free-Molecule Flow

Comparison of free-molecule-flow theory with the results of wind-tunnel tests performed to determine the drag and temperature-rise characteristics of a transverse circular cylinder.
Date: 1951
Creator: Stalder, Jackson R.; Goodwin, Glen & Creager, Marcus O.
System: The UNT Digital Library
Nomenclature for Aeronautics (open access)

Nomenclature for Aeronautics

The nomenclature for aeronautics presented in this Report No. 474 is a revision of the last previous report on this subject (i.e., Report no. 240.) This report is published for the purpose of encouraging greater uniformity and precision in the use of terms relating to aeronautics, both in official documents of the Government and in commercial publications. Terms in general use in other branches of engineering have been included only where they have some special significance in aeronautics, or form an integral part of its terminology.
Date: 1939
Creator: unknown
System: The UNT Digital Library
A Theoretical Investigation of Longitudinal Stability of Airplanes with Free Controls Including Effect of Friction in Control System (open access)

A Theoretical Investigation of Longitudinal Stability of Airplanes with Free Controls Including Effect of Friction in Control System

"The relation between the elevator hinge moment parameters and the control forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short period oscillations is shown as a series of boundaries giving the limits of the stable regions in terms of the elevator hinge moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considered" (p. 1).
Date: 1944
Creator: Greenberg, Harry & Sternfield, Leonard
System: The UNT Digital Library
Icing-Protection Requirements for Reciprocating-Engine Induction Systems (open access)

Icing-Protection Requirements for Reciprocating-Engine Induction Systems

Report presenting an investigation of the icing of aircraft-engine induction systems. Criterions for safe operation and for the design of new induction system are established through the investigation. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations.
Date: 1950
Creator: Coles, Willard D.; Rollin, Vern G. & Mulholland, Donald R.
System: The UNT Digital Library
Lifting-Surface-Theory Aspect-Ratio Corrections to the Lift and Hinge-Moment Parameters for Full-Span Elevators on Horizontal Tail Surfaces (open access)

Lifting-Surface-Theory Aspect-Ratio Corrections to the Lift and Hinge-Moment Parameters for Full-Span Elevators on Horizontal Tail Surfaces

"A limited number of lifting-surface-theory solutions for wings with chordwise loadings resulting from angle of attack, parabolic-arc camber, and flap deflection are now available. These solutions were studied with the purpose of determining methods of extrapolating the results in such a way that they could be used to determine lifting-surface-theory values of the aspect-ratio corrections to the lift and hinge-moment parameters for both angle-of-attack and flap-deflection-type loading that could be used to predict the characteristics of horizontal tail surfaces from section data with sufficient accuracy for engineering purposes. Such a method was devised for horizontal tail surfaces with full-span elevators" (p. 1).
Date: 1948
Creator: Swanson, Robert S. & Crandall, Stewart M.
System: The UNT Digital Library
Determination of the Profile Drag of an Airplane Wing in Flight at High Reynolds Numbers (open access)

Determination of the Profile Drag of an Airplane Wing in Flight at High Reynolds Numbers

Report presenting flight tests to determine the profile-drag coefficients of a portion of the original wing surface of an all-metal airplane and a portion of the wing made aerodynamically smooth and more nearly fair than the original section. Tests were also carried out to determine the point of transition from laminar to turbulent boundary layer and to determine the velocity distribution along the upper surface of the wing.
Date: 1939
Creator: Bicknell, Joseph
System: The UNT Digital Library
Ice Prevention on Aircraft by Means of Engine Exhaust Heat and a Technical Study of Heat Transmission From a Clark Y Airfoil (open access)

Ice Prevention on Aircraft by Means of Engine Exhaust Heat and a Technical Study of Heat Transmission From a Clark Y Airfoil

"This investigation was conducted to study the practicability of employing heat as a means of preventing the formation of ice on airplane wings. The report relates essentially to technical problems regarding the extraction of heat from the exhaust gases and its proper distribution over the exposed surfaces. In this connection a separate study has been made to determine the variation of the coefficient of heat transmission along the chord of a Clark Y airfoil. Experiments on ice prevention both in the laboratory and in flight show conclusively that it is necessary to heat only the front portion of the wing surface to effect complete prevention" (p. 3).
Date: June 12, 1931
Creator: Theodorsen, Theodore & Clay, William C.
System: The UNT Digital Library
Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig (open access)

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.
Date: 1952
Creator: Macks, E. Fred & Nemeth, Zolton N.
System: The UNT Digital Library
An Introduction to the Laws of Air Resistance of Aerofoils (open access)

An Introduction to the Laws of Air Resistance of Aerofoils

Report presents methods of calculating air resistance of airfoils under certain conditions of flow phenomena around the airfoil.
Date: September 1918
Creator: de Bothezat, George
System: The UNT Digital Library
On the plane potential flow past a lattice of arbitrary airfoils (open access)

On the plane potential flow past a lattice of arbitrary airfoils

The two-dimensional, incompressible potential flow past a lattice of airfoils of arbitrary shape is investigated theoretically. The problem is treated by usual methods of conformal mapping in several stages, one stage corresponding to the mapping of the framework of the arbitrary line lattice and another significant stage corresponding to the Theodorsen method for the mapping of the arbitrary single wing profile into a circle. A particular feature in the theoretical treatment is the special handling of the regions at an infinite distance in front of and behind the lattice. Expressions are given for evaluation of the velocity and pressure distribution at the airfoil boundary. An illustrative numerical example is included.
Date: November 19, 1943
Creator: Garrick, I. E.
System: The UNT Digital Library
Icing-protection requirements for reciprocating-engine induction system (open access)

Icing-protection requirements for reciprocating-engine induction system

From Summary: "Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied."
Date: June 20, 1949
Creator: Coles, Willard D.; Rollin, Vern G. & Mulholland, Donald R.
System: The UNT Digital Library
Line-Vortex Theory for Calculation of Supersonic Downwash (open access)

Line-Vortex Theory for Calculation of Supersonic Downwash

"The perturbation field induced by a line vortex in a supersonic stream and the downwash behind a supersonic lifting surface are examined to establish approximate methods for determining the downwash behind supersonic wings. Lifting-lines methods are presented for calculating supersonic downwash. A bent lifting-line method is proposed for computing the downwash field behind swept wings. When applied to triangular wings with subsonic leading edges, this method gives results that, in general, are in good agreement with the exact linearized solution" (p. 635).
Date: April 29, 1949
Creator: Mirels, Harold & Haefeli, Rudolph C.
System: The UNT Digital Library
A radar method of calibrating airspeed installations on airplanes in maneuvers at high altitudes and at transonic and supersonic speeds (open access)

A radar method of calibrating airspeed installations on airplanes in maneuvers at high altitudes and at transonic and supersonic speeds

A method of calibrating the static-pressure source of a pitot static airspeed installation on an airplane in level flight, dives, and other maneuvers at high altitude and at transonic and supersonic speeds is described. The method principally involves the use of radar-phototheodolite tracking equipment. The various sources of error in the method are discussed and sample calibrations are included.
Date: August 31, 1949
Creator: Zalovcik, John A.
System: The UNT Digital Library