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Wind-Tunnel Investigation of Icing of an Engine Cooling-Fan Installation
Note presenting an investigation of the icing characteristics and means of ice protection of a typical radial-engine cooling-fan installation. The icing of the unprotected cooling-fan installation was found to present a serious operational problem. Results regarding icing, steam heat de-icing, alcohol de-icing, and electrical heat de-icing are provided.
Date:
April 1947
Creator:
Lewis, James P.
System:
The UNT Digital Library
A Flight Evaluation and Analysis of the Effect of Icing Conditions on the ZPG-2 Airship
"A series of test flights was conducted by the U. S. Navy over a 3- year period to evaluate the effects of icing on the operation of the ZPG-2 airship. In supercooled. clouds, ice formed only on the forward edges of small protuberances and wires and presented no serious hazard to operation. Ice accretions of the glaze type which occurred in conditions described as freezing drizzle adversely affected various components to a somewhat greater extent" (p. 1).
Date:
April 1958
Creator:
Lewis, William & Perkins, Porter J., Jr.
System:
The UNT Digital Library
A Flight Investigation of the Thermal Performance of Air Heated Propeller
Note presenting the thermal performance of an air-heated propeller, installed on a test airplane, as evaluated by observations of the ice-prevention properties of the propeller during flight in natural icing conditions and by the collection of thermal data on the propeller during flight in clear air and in clouds at temperatures above freezing. The results indicated that the air-heated-propeller installation tested would offer little or no protection to the leading-edge regions of the propeller during flight in severe natural-icing conditions.
Date:
April 1947
Creator:
Darsow, John F. & Selna, James
System:
The UNT Digital Library
Perforated Sheets as a Porous Material for Distributed Suction and Injection
Note presenting measurements made of the resistance to air flow of a series of perforated metal sheets with open areas ranging from less than 1 percent up to 41 percent. The results showed that the permeability of a perforated sheet is governed principally by its open-area ratio. The number of holes per square inch, the sheet thickness, and the shape of the individual holes had little or no effect on permeability.
Date:
April 1956
Creator:
Dannenberg, Robert E.; Gambucci, Bruno J. & Weiberg, James A.
System:
The UNT Digital Library
A Method for Determining Cloud-Droplet Impingement on Swept Wings
From Summary: "The general effect of wing sweep on cloud-droplet trajectories about swept wings of high aspect ratio moving at subsonic speeds is discussed. A method of computing droplet trajectories about yawed cylinders and swept wings is presented, and illustrative droplet trajectories are computed. A method of extending two-dimensional calculations of droplet impingement on nonswept wings to swept wings is presented."
Date:
April 1953
Creator:
Dorsch, Robert G. & Brun, Rinaldo J.
System:
The UNT Digital Library
A Simple Method of Estimating the Subsonic Lift and Damping in Roll of Sweptback Wings
"A method of modifying existing correction factors of lifting-surface theory to account approximately for the effects of sweep was derived, and these factors were applied to existing lifting-line theories for the lift and damping in roll of swept wings. Despite the simplicity of the resulting formulas the agreement with experimental data for low speeds is very good. The equation for lift is expressed entirely in terms of the geometric characteristics of the wing and the section-lift-curve; the necessity for any charts is thereby eliminated" (p. 1).
Date:
April 1949
Creator:
Polhamus, Edward C.
System:
The UNT Digital Library
Tests of a gust-alleviating wing in the gust tunnel
"Tests were made in the NACA gust tunnel to determine the effectiveness of a torsionally flexible wing with the torsion axis ahead of the locus of the section aerodynamic centers in reducing airplane accelerations due to atmospheric gusts. For three gust shapes, a series of flights was made with the airplane model equipped with either a torsionally flexible or a rigid wing. The results indicated that the torsionally flexible wing reduced the maximum acceleration increment 5 percent for the sharp-edge gust and about 17 percent for gust shapes with gradient distances of 6.8 and 15 chord lengths" (p. 1).
Date:
April 1941
Creator:
Shufflebarger, C. C.
System:
The UNT Digital Library
The Interference Effects of a Body on the Spanwise Load Distributions of Two 45 Degree Sweptback Wings of Aspect Ratio 8.02 from Low-Speed Tests
From Summary: "Tests of two wing-body combinations have been conducted in the Langley 19-foot pressure tunnel at a Reynolds number of 4 x 10(exp 6) and a Mach number of 0.19 to determine the effects of the bodies on the wing span load distributions. The wings had 45 degrees sweepback of the quarter-chord line, aspect ratio 8.02, taper ratio 0.45, and incorporated 12-percent-thick airfoil sections streamwise. One wing was untwisted and uncambered whereas the second wing incorporated both twist and camber. Identical bodies of revolution, of 10:1 fineness ratio, having diameter-to-span ratios of 0.10, were mounted in mid-high-wing arrangements."
Date:
April 1956
Creator:
Martina, Albert P.
System:
The UNT Digital Library
Variation of Local Liquid-Water Concentration About an Ellipsoid of Fineness Ratio 10 Moving in a Droplet Field
From Summary: "Trajectories of water droplets about an ellipsoid of revolution with a fineness ratio of 10 (10 percent thick) in flight through a droplet field were computed with the aid of a differential analyzer. Analyses of these trajectories indicate that the local concentration of liquid water at various points about an ellipsoid varies considerably and under some conditions may be several times the free-stream concentration. Curves of the local concentration factor as a function of spatial position were obtained and are presented in terms of dimensionless parameters that describe flight and atmospheric conditions."
Date:
April 1955
Creator:
Brun, Rinaldo J. & Dorsch, Robert G.
System:
The UNT Digital Library
Center of pressure coefficients for airfoils at high speeds
"It has been customary to calculate the strength of the rear wing beam for the 'high speed' condition on the assumption that the center of pressure was at 0.50 of the wing chord. It can be shown that this assumption is not justified, regardless of the utility of a 'high speed' condition in strength calculations" (p. 1).
Date:
April 1922
Creator:
Diehl, W. S.
System:
The UNT Digital Library
On the Resistance of the Air at High Speeds and on the Automatic Rotation of Projectiles
Here, the laws governing the flow of a compressible fluid through an opening in a thin wall are applied to the resistance of the air at high speeds, especially as applied to the automatic rotation of projectiles. The instability which we observe in projectiles shot into the air without being given a moment of rotation about their axis of symmetry, or without stabilizing planes, is a phenomenon of automatic rotation. It is noted that we can prevent this phenomenon of automatic rotation by bringing the center of gravity sufficiently near one end, or by fitting the projectile with stabilizing planes or a tail.
Date:
April 1921
Creator:
Riabouchinski, D.
System:
The UNT Digital Library
Gordon Bennett Airplane Cup 1920
The characteristics of the airplanes built for the Gordon Bennett Airplane Cup race that took place on September 28, 1920 are described. The airplanes are discussed from a aerodynamical point of view, with a number of new details concerning the French machines. Also discussed is the regulation of future races. The author argues that there should be no limitations on the power of the aircraft engines. He reasons that in the present state of things, liberty with regard to engine power does not lead to a search for the most powerful engine, but for one which is reliable and light, thus leading to progress.
Date:
April 1921
Creator:
Margoulis, W.
System:
The UNT Digital Library
Similitude tests on wing sections
Report presenting an exploration of the application of model test results to full size construction, which assumes that either the resistance varies as the square of the speed within, the range of speeds in question or that the mechanical similarity law is fulfilled by the model test. The latter requires that the relation of airflow to the model be exactly like that for the large machine.
Date:
April 1921
Creator:
Kumbruch, H. & Bacon, D. L.
System:
The UNT Digital Library
Notes on Propeller Design 2:The Distribution of Thrust Over a Propeller Blade
The best distribution of the thrust over the length of the propeller blade is investigated, taking into account chiefly the slipstream loss and the friction between the blades and the air.
Date:
April 1922
Creator:
Munk, Max M.
System:
The UNT Digital Library
Notes on Propeller Design 1: The Energy Losses of the Propeller
The different kinds of energy losses of the propeller and the values of the constants determining them are discussed.
Date:
April 1922
Creator:
Munk, Max M.
System:
The UNT Digital Library
Full Scale Determination of the Lift and Drag of a Seaplane
The speed, barometric pressure, and number of revolutions of the engine of a seaplane were measured, including tests with stopped engine. The mean data obtained are given in the following note; the results of the gliding tests are used for the computation of the lift and drag coefficients, and by making use of them the results of the engine flights are used for the computation of the propeller efficiency.
Date:
April 1922
Creator:
Munk, Max M.
System:
The UNT Digital Library
The Background of Detonation
Note presenting a determination of the relative merits of various fuels for use in high compress engines. The main purpose is to discuss a phase that has not been given much attention in previous studies; specifically, the standpoint of the influence of charge temperatures and pressures on the temperatures and pressures after combustion.
Date:
April 1922
Creator:
Sparrow, Stanwood W.
System:
The UNT Digital Library
Notes on Longitudinal Stability and Balance
Report detailing studies of longitudinal stability and balance on five airplanes: the JN4H, DH4, VE7, USAC-11, and Martin Transport. The methods of measurement, methods of correcting instability, and potential modifications for the elevator of the planes is described.
Date:
April 1920
Creator:
Warner, E. P.
System:
The UNT Digital Library
Recent European Developments in Helicopters
Descriptions are given of two captured helicopters, one driven by electric power, the other by a gasoline engine. An account is given of flight tests of the gasoline powered vehicle. After 15 successful flight tests, the gasoline powered vehicle crashed due to the insufficient thrust. Also discussed here are the applications of helicopters for military observations, for meteorological work, and for carrying radio antennas.
Date:
April 1921
Creator:
unknown
System:
The UNT Digital Library
Testing Airplane Fabrics
"The following considerations determine the strength of airplane fabrics: 1. maximum air forces acting on the surfaces (including local stresses); 2. tensions produced in the fabrics, in the directions of both warp and filling; 3. factor of safety required. The question of the permissible depression of the fabric as affecting the aerodynamic requirements in regard to the maintenance of shape of the section, the tenacity and extensibility of the layer of dope, its strength and its permeability to water is almost as important" (p. 1).
Date:
April 1924
Creator:
Pröll, A.
System:
The UNT Digital Library
The Induction Factor Used for Computing the Rolling Moment Due to the Ailerons
In the following note, prepared for the National Advisory Committee for Aeronautics, this induction factor is determined from the result of a model test, and compared with a formula recently developed by the author. The two results are found to be in substantial agreement.
Date:
April 1924
Creator:
Munk, Max M.
System:
The UNT Digital Library
Longitudinal oscillation of an airplane Part 1: problem and method
Report presenting some theoretical calculations for determining the problems of accelerated and disturbed motion, phenomena in an accidental or intentional disturbance through the deflection of the rudder or elevator, or any other change in the conditions of flight.
Date:
April 1924
Creator:
Fuchs, R. & Hopf, L.
System:
The UNT Digital Library
Torsional Strength of Nickel Steel and Duralumin Tubing as Affected by the Ratio of Diameter to Gage Thickness
"This investigation was made at the request of the Bureau of Aeronautics. Since the ordinary torsion formula is based on elastic resistance to deformation, it is inaccurate for determination of ultimate stresses in thin wall tubing subjected to torsional loads. It has been found that the torsional modulus of rupture varies with the ratio of diameter to gage thickness and the object of these tests was to determine the extent of these variations for subject materials. This is somewhat of a prorogation of work done by the Army Air Service at McCook Field" (p. 1).
Date:
April 1924
Creator:
Otey, N. S.
System:
The UNT Digital Library
Comparing the Performance of Geometrically Similar Airplanes
"This note has been prepared for the National Advisory Committee for Aeronautics. It deals with the model rules relating to aeronautical problems, and shows how the characteristics of one airplane can be determined from those of another airplane of different weight or size, and of similar type. If certain rules for the ratios of the dimensions, the weights and the horsepower are followed, a small low-powered airplane can be used for obtaining information as to performance, stability, controllability and maneuverability of a larger prototype, and contrariwise" (p. 1).
Date:
April 1924
Creator:
Munk, Max M. & Warner, Edward P.
System:
The UNT Digital Library