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Design of Recording Wind Tunnel Balances

Description: Given here is a description of the design of a scientific recording wind tunnel balance. It was decided that the most satisfactory arrangement would be a rigid ring completely surrounding the tunnel or wind stream, so that the model could be supported from it by wires or any arrangement of spindles. The forces and moments acting on this ring can then be recorded by suitable weighing apparatus. The methods available for recording forces on the arms are explained. The proposed type of balance wil… more
Date: December 1920
Creator: Norton, F. H.
Partner: UNT Libraries Government Documents Department
open access

High thermal efficiency in airplane service

Description: Described here is a method by which high average fuel economy has been achieved in aircraft engines. Details are given of the design of certain foreign engines that employ an unusual type of fuel-air ratio control in which the change in power produced by a mixture change is due almost entirely to the change in the power producing ability of the unit weight of the mixture. The safety and performance features of this type of control are explained.
Date: December 1920
Creator: Sparrow, S. W.
Partner: UNT Libraries Government Documents Department
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Instrument for measuring engine clearance volumes

Description: With the advent of the V type engine, a new method to measure the clearance volume in cylinders was needed. It was suggested that this measurement could be made by a process which consisted essentially of simultaneously changing both a known and unknown volume of gas by a known amount and then calculating the magnitude of the unknown from the resulting difference in pressure between the two. An instrument based on this design is described.
Date: December 1920
Creator: Sparrow, S. W.
Partner: UNT Libraries Government Documents Department
open access

Progress Made in the Construction of Giant Airplanes in Germany During the War

Description: The construction of giant airplanes was begun in Germany in August, 1914. The tables annexed here show that a large number of airplanes weighing up to 15.5 tons were constructed and tested in Germany during the War, and it is certain that no other country turned out airplanes of this weight nor in such large numbers. An examination of the tables shows that by the end of the War all the manufacturers had arrived at a well-defined type, namely an airplane of about 12 tons with four engines of 260… more
Date: December 1920
Creator: Baumann, A.
Partner: UNT Libraries Government Documents Department
open access

The Steadiness Factor in Engine Sets

Description: Technical notes discussing the steadiness factor in engines and the calculations that can be used to arrive at it. Factors affecting the steadiness factor are detailed, including the mass of parts, torque, engine rotation, and power.
Date: December 1920
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
open access

A Variable Speed Fan Dynamometer

Description: Fan brakes used as absorption dynamometers in testing internal combustion engines have the disadvantage that a given fan will run only at one speed when the engine is delivering full power. In order to be able to vary the speed at which a given power will be absorbed, English manufacturers have for some time been using a cylindrical housing around the fan with one or two variable openings in the periphery. Here, results are given of tests conducted to determine how great a range of speed can be… more
Date: December 1920
Creator: Wood, Karl D.
Partner: UNT Libraries Government Documents Department
open access

Effects of Varying the Relative Vertical Position of Wing and Fuselage

Description: "The object of this series of experiments was to determine the influence of the relative vertical position of wing and fuselage on the efficiency of the wing. Since the longitudinal position of the wing can be varied but slightly with reference to the center of gravity in a normal airplane, it was kept constant in the experiments to be described and only the vertical position of the wing with reference to the fuselage was varied" (p. 1).
Date: December 1921
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department
open access

Ground Influence on Aerofoils

Description: The question of ground influence on airplanes has recently attracted some attention in view of the claims made by certain designers that the landing speed of their airplanes is much decreased by an increase in lift coefficient due to the proximity of the ground in landing. The results of wind tunnel tests indicate that ground effect is not entirely beneficial. It decreases the landing speed and cushions the landing shock somewhat. However, it does so at the expense of an increased length of pre… more
Date: December 1921
Creator: Raymond, Arthur E.
Partner: UNT Libraries Government Documents Department
open access

A Mechanical Device for Illustrating Airplane Stability

Description: An instrument is described which will illustrate completely in a qualitative sense the longitudinal stability characteristics of an airplane. The instrument is primarily of use for the lecture room, but it is hoped that ultimately it will be possible to obtain quantitative results from it.
Date: December 1921
Creator: Norton, F. E.
Partner: UNT Libraries Government Documents Department
open access

Mutual Influence of Wings and Propeller

Description: Report presenting an experiment consisting of an aerofoil and propeller in order to discover the mutual influence between the two components and variations in moment due to the propeller influence.
Date: December 1921
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department
open access

Further Information on the Laws of Fluid Resistance

Description: Note presenting experiments with cylinders of different shapes and some of the strange phenomena that manifested in connection with the cylinder.
Date: December 1922
Creator: Wieselsberger, C.
Partner: UNT Libraries Government Documents Department
open access

Compressive Strength of Tapered Airplane Struts

Description: Note presenting methods for ascertaining the value of n in Euler's simplified formula, which can be used for the compressive strength of tapered airplane struts, by estimating from curves and by calculation.
Date: December 1923
Creator: Lewe, Viktor
Partner: UNT Libraries Government Documents Department
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Compressive Strength of Tapered Airplane Struts

Description: Methods are here given for ascertaining the value of n in Euler's simplified formula, P = n (EI/l(sup 2)), for the compressive strength of tapered airplane struts, by estimating from curves and by calculation.
Date: December 1923
Creator: Lewe, Viktor
Partner: UNT Libraries Government Documents Department
open access

Experiments With Fabrics for Covering Airplane Wings, to Determine Effect of Method of Installation

Description: Note presenting some information on the effect of changes in the loading and in the disposition of the supporting framework on the covering fabric. The magnitude of the air forces to be taken into account and the corresponding factors of safety to be expected will be covered in a future report. Tables regarding some of these fabric characteristics are provided.
Date: December 1923
Creator: Pröll, A.
Partner: UNT Libraries Government Documents Department
open access

The Nichols Wing Cutting Equipment

Description: Described here is wing cutting equipment for the economical production of metal wings for wind tunnel models. The machine will make any size of constant-section wing or strut up to one-sixth inch chord by 36-inch span and up to a thickness of one and one-quarter inches. It cuts a smooth, true model that is accurate to within two-thousandths of an inch on any ordinate. The holding jaws are so designed as to leave the model free of chip marks, and the only hand finishing necessary after the cutti… more
Date: December 1923
Creator: Ford, James B.
Partner: UNT Libraries Government Documents Department
open access

Reduction in Efficiency of Propellers Due to Slipstream

Description: "In the slipstream behind a propeller there is a considerable amount of kinetic energy which has been imparted to it by the engine without producing any corresponding propeller thrust. The increased absorption of power reduces the propeller efficiency. Attention has been previously directed to this question by Bendemann and Madelung and other writers. Their contribution serves to verify a simple method of calculating the reduction in the propeller efficiency due to the slip stream" (p. 1).
Date: December 1923
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department
open access

The Testing of Aviation Engines Under Approximate Altitude Conditions

Description: Note presenting a description of the aviation testing laboratory that has been built at the Bureau of Standards in order to test aviation engines under approximate engine conditions. A description of some of the calculations that are used to compare experimental and theoretical results are provided.
Date: December 1924
Creator: DuBois, R. N.
Partner: UNT Libraries Government Documents Department
open access

Tests of rotating cylinders

Description: Tests were made in the no. 1 (5 ft. atmospheric) wind tunnel at Langley Memorial Aeronautical Laboratory to determine the air forces acting on rotating cylinders with axes perpendicular to the direction of motion. Two cylinders were tested, one with a circular cross-section and the other with a Greek cross. The cross cylinder and compound strut were found to not be as efficient as the circular one.
Date: December 1924
Creator: Reid, Elliott G.
Partner: UNT Libraries Government Documents Department
open access

Resistance of a fifteen-centimeter disk

Description: "The results of this test show that the dynamic scale has very little effect on the drag coefficient of a disk over a wide range of Reynolds Number. A comparison of these results with those of tests made on a series of disks at Göttingen University furnishes a good check on the method of testing in this tunnel" (p. 1).
Date: December 1926
Creator: Shoemaker, James M.
Partner: UNT Libraries Government Documents Department
open access

Wind Tunnel Standardization Disk Drag

Description: Note presenting the resistances of a series of three similar disks placed normal to the wind as determined in the atmospheric wind tunnel. The curves of drag coefficient plotted against Reynolds number for this tunnel show discrepancies between overlapping values which are to be attributed to the presence of the tunnel walls.
Date: December 1926
Creator: Knight, Montgomery
Partner: UNT Libraries Government Documents Department
open access

The Characteristics of the N.A.C.A 97, Clark Y, and N.A.C.A. M6 Airfoils with Particular Reference to the Angle of Attack

Description: Report examining the aerodynamic characteristics of three airfoil sections as determined in the variable density wind tunnel. Particular attention is given to the relation of the characteristics to the angle of attack and their use in airplane design.
Date: December 1927
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department
open access

Some effects of air flow on the penetration and distribution of oil sprays

Description: Tests were made to determine the effects of air flow on the characteristics of fuel sprays from fuel injection valves. Curves and photographs are presented showing the airflow throughout the chamber and the effects of the air flow on the fuel spray characteristics. It was found that the moving air had little effect on the spray penetration except with the 0.006 inch orifice. The moving air did, however, affect the oil particles on the outside of the spray cone. After spray cut-off, the air flow… more
Date: December 1929
Creator: Rothrock, A. M. & Beardsley, E. G.
Partner: UNT Libraries Government Documents Department
open access

Wind tunnel pressure distribution tests on a series of biplane wing models Part III: effects of charges in various combinations of stagger, gap, sweepback, and decalage

Description: A concept for the calculation of the vortex lift of sharp-edge delta wings is presented and compared with experimental data. The concept is based on an analogy between the vortex lift and the leading-edge suction associated with the potential flow about the leading edge. This concept, when combined with potential-flow theory modified to include the nonlinearities associated with the exact boundary condition and the loss of the lift component of the leading-edge suction, provides excellent predi… more
Date: December 1929
Creator: Knight, Montgomery & Noyes, Richard W.
Partner: UNT Libraries Government Documents Department
open access

A balanced diaphragm type of maximum cylinder pressure indicator

Description: A balanced diaphragm type of maximum cylinder pressure indicator was designed to give results consistent with engine operating conditions. The apparatus consists of a pressure element, a source of controlled high pressure and a neon lamp circuit. The pressure element, which is very compact, permits location of the diaphragm within 1/8 inch of the combustion chamber walls without water cooling. The neon lamp circuit used for indicating contact between the diaphragm and support facilitates the us… more
Date: December 1930
Creator: Spanogle, J. A. & Collins, John H., Jr.
Partner: UNT Libraries Government Documents Department
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