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Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing

Description: From Summary: "Two topics of interest to persons attempting to apply the heat method of preventing ice formation on aircraft are considered. Surfaces moving through air at high speed are shown, both theoretically and experimentally, to be subject to important aerodynamic heating effects that will materially reduce the heat required to prevent ice. Numerical calculations of the path of water drops in an air stream around a circular cylinder are given. From these calculations, information is obta… more
Date: October 1940
Creator: Kantrowitz, Arthur
Partner: UNT Libraries Government Documents Department
open access

The Cause of Welding Cracks in Aircraft Steels

Description: The discussion in this article refers to gas welding of thin-walled parts of up to about 3 mm thickness. It was proven that by restricting the sulphur, carbon, and phosphorous content, and by electric-furnace production of the steel, it was possible in a short time to remove this defect. Weld hardness - i.e., martensite formation and hardness of the overheated zone - has no connection with the tendency to weld-crack development. Si, Cr, Mo, or V content has no appreciable effect, while increase… more
Date: October 1940
Creator: Müller, J.
Partner: UNT Libraries Government Documents Department
open access

Corrections on the Thermometer Reading in an Air Stream

Description: A method is described for checking a correction formula, based partly on theoretical considerations, for adiabatic compression and friction in flight tests and determining the value of the constant. It is necessary to apply a threefold correction to each thermometer reading. They are a correction for adiabatic compression, friction and for time lag.
Date: October 1940
Creator: Van der Maas, H. J. & Wynia, S.
Partner: UNT Libraries Government Documents Department
open access

Drag Analysis of Single-Engine Military Airplanes Tested in the NACA Full-Scale Wind Tunnel

Description: Report presenting tests in the full-scale wind tunnel on 11 single-engine military airplanes to investigate methods for increasing their high speed. Results regarding the power-plant installation, flow characteristics, wings, cockpit canopies, landing gear, and air leakage are provided.
Date: October 1940
Creator: Dearborn, C. H. & Silverstein, Abe
Partner: UNT Libraries Government Documents Department
open access

Full-Scale Tests of Several Propellers Equipped with Spinners, Cuffs, Airfoil and Round Shanks, and NACA 16-Series Sections, Special Report

Description: "Wind-tunnel tests of several propeller, cuff, and spinner combinations were conducted in the 20 foot propeller-research tunnel. Three propellers, which ranged in diameter from 8.4 to 11.25 feet, were tested at the front end of a streamline body incorporating spinners of two diameters. The tests covered a blade angle range from 20 deg to 65 deg. The effect of spinner diameter and propeller cuffs on the characteristics of one propeller was determined" (p. 1).
Date: October 1940
Creator: Biermann, David; Hartman, Edwin P. & Pepper, Edward
Partner: UNT Libraries Government Documents Department
open access

Internal-Flow Systems for Aircraft

Description: "An investigation has been made to determine efficient arrangements for an internal-flow system of an aircraft when such a system operates by itself or in combination with other flow systems. The investigation included a theoretical treatment of a problem and tests in the NACA 5-foot vertical wind tunnel of inlet and outlet openings in a flat plate and in a wing. When an internal-flow system tends to decrease the final velocity of it's wake, the results showed that it should be arranged in seri… more
Date: October 1940
Creator: Rogallo, F. M.
Partner: UNT Libraries Government Documents Department
open access

Mathematical Analysis of Aircraft Intercooler Design

Description: "A mathematical analysis has been made to show the method of obtaining the dimensions of the intercooler that will use the least total power for a given set of design conditions. The results of this analysis have been used in a sample calculation and, on the basis of this calculation, a new inter cooler arrangement is suggested. Because the length of the two air passages of the new arrangement is short in comparison with the third dimension, the height of the intercooler, this intercooler arran… more
Date: October 1940
Creator: Joyner, Upshur T.
Partner: UNT Libraries Government Documents Department
open access

Measured Moments of Inertia of 32 Airplanes

Description: "A compilation of the experimentally determined moments of inertia of 32 airplanes is presented. The measurements were obtained at the laboratories of the NACA by means of a pendulum method. The airplanes tested are representative of several types of aircraft of gross weight less than 10,000 pounds. The results are presented in coefficient as well as in dimensional form. An elementary analysis of the data disclosed the possibility of grouping the results according to wing type of the airplane, … more
Date: October 1940
Creator: Gracey, William
Partner: UNT Libraries Government Documents Department
open access

Notes on the stalling of vertical tail surfaces and on fin design

Description: From Summary: "A discussion is given of the important aspects of the stalling of vertical tail surfaces. The type of instability encountered is described and the possibilities of inadvertent occurrence are noted. The influence of directional flight tests on the behavior of a airplane when the tail stall takes place is discussed. In this connection, flight tests of a twin-engine airplane in which the vertical fin area was increased are cited."
Date: October 1940
Creator: Thompson, F. L. & Gilruth, R. R.
Partner: UNT Libraries Government Documents Department
open access

Resonance Vibrations in Intake and Exhaust Pipes of in-Line Engines 3: The Inlet Process of a Four-Stroke-Cycle Engine

Description: Using a previously developed method, the boundary process of four-stroke-cycle engines are set up. The results deviate considerably from those obtained under the assumption that the velocity fluctuation is proportional to the cylinder piston motion. The deviation is less at the position of resonance frequencies. By the method developed, the effect of the resonance vibrations on the volumetric efficiency can be demonstrated.
Date: October 1940
Creator: Lutz, O.
Partner: UNT Libraries Government Documents Department
open access

Wind Tunnel Tests of a Submerged-Engine Fuselage Design

Description: Report presenting tests conducted in the 8-foot high-speed wind tunnel of a scale model pursuit-type fuselage with practicable internal duct arrangement designed to meet all of the air requirements of a 1000-horsepower radial engine submerged at the maximum section. The results showed that the required internal flow can be obtained with negligible ducting losses provided that basic principles are observed in designing the air passages.
Date: October 1940
Creator: Becker, John V. & Baals, Donald D.
Partner: UNT Libraries Government Documents Department
open access

Additional power-on wind-tunnel tests of the 1/8-scale model of the Brewster F2A airplane with full-span slotted flaps

Description: "Additional tests as recommended in reference 1 were made in the 7- by 10-foot wind tunnel of the 1/8-scale model of the Brewster F2A airplane to determine the angle of attack of horizontal tail and the elevator angles required for trim with flaps down" (p. 1).
Date: October 1941
Creator: Lowry, John G.
Partner: UNT Libraries Government Documents Department
open access

Aerodynamic Factors Affecting the Ability of a Pilot to Return an Airplane to Level From a Banked Attitude by Use of the Rudder Alone and Without Change of Heading

Description: Report presenting a study of the aerodynamic factors upon which the ability to perform the maneuver depends in an attempt to obtain a better understanding of the conditions involved and, if possible, to evolve criterions that may be used during design.
Date: October 1941
Creator: Harmon, S. M.
Partner: UNT Libraries Government Documents Department
open access

Buckling Tests on Eccentrically Loaded Beam Columns

Description: "Formulas are obtained for computing the buckling load of rods eccentrically loaded at each end, the computation being extended in particular to the inelastic range. The test results are graphically presented on three sets of curves. Two of these, at least for the elastic range, are independent of the material tested. The third set, which is independent of the material, possesses greater clearness and is therefore used for comparing the test results with the theoretical" (p. 1).
Date: October 1941
Creator: Cassens, J.
Partner: UNT Libraries Government Documents Department
open access

Contribution to the Aerodynamics of Rotating-Wing Aircraft: Part 2

Description: "The interrelations established in an earlier report (NACA-TM-921) are used to study the best assumptions for hovering and horizontal flight. The effect of the twisted and tapered blade on the rotor efficiency is analyzed and the gliding coefficient at different stages (from autogyro to helicopter) of horizontal flight compared. To the extent that model or full-scale test data are available, they are included in the comparison" (p. 1).
Date: October 1941
Creator: Sissingh, G.
Partner: UNT Libraries Government Documents Department
open access

Damping characteristics of dashpots

Description: An investigation of the damping characteristics of dashpots was carried out combining theory and experiment. Laminar flow was assumed and three equations for the steady velocity of a piston moving in a cylinder filled with liquid were derived. In the first equation, the piston was assumed coaxial in the cylinder and, in the second equation, the piston was assumed eccentric in the cylinder with an element of the piston in contact with the cylinder wall. The third equation is for a piston of circ… more
Date: October 1941
Creator: Peterson, John B.
Partner: UNT Libraries Government Documents Department
open access

Development of Cowling for Long-Nose Air-Cooled Engine in the NACA Full-Scale Wind Tunnel

Description: "An investigation of cowlings for long-nose radial engines was made on the Curtiss XP-42 fighter in the NACA full-scale wind tunnel. The unsatisfactory aerodynamic characteristics of all the cowlings with scoop inlets tested led to the development of the annular high-velocity inlet cowlings. Tests showed that ratio of cooling-air velocity at cowling inlet to stream velocity should not be less than 0.5 for this type of cowling and that critical compressibility speed can be extended to more than … more
Date: October 1941
Creator: Silverstein, Abe & Guryansky, Eugene R.
Partner: UNT Libraries Government Documents Department
open access

The effects of hub drag, solidity, dual rotation, and number of blades upon the efficiency of high-pitch propellers

Description: Report presenting an investigation of the effects of hub drag, solidity, dual rotation, and number of blades on the efficiency of high-pitch propellers. Testing occurred with two, three, four, and six-blade single propellers and four and six-blade dual-rotating propellers equipped with spinners and tested at a range of blade angles from 35 to 65 degrees. Results regarding a comparison of the large and small spinners, effects of spinners, comparison of constant-speed propellers, characteristics … more
Date: October 1941
Creator: Reid, Elliott G.
Partner: UNT Libraries Government Documents Department
open access

Flight Investigation of Wing-Gun Fairings on a Fighter Type Airplane

Description: Description is given of flight tests conducted on gun fairings, designed to correct the detrimental effects of the projecting and submerged wing guns on an F4F-3 fighter. It was found that the installation of unfaired guns on a clean wing resulted in a premature stall that increased the stalling speed in the carrier-approach and landing conditions of flight by suitably fairing the guns, it was possible to reduce the stalling speeds to values approaching very nearly the clean-wing values.
Date: October 1941
Creator: Nissen, J. M. & White, M. D.
Partner: UNT Libraries Government Documents Department
open access

Investigation of Air Flow in Right-Angle Elbows in a Rectangular Duct

Description: Report presenting testing on elbow shapes in airplane carburetor air intake ducts with low losses and good velocity distribution without the use of turning vanes. Results regarding the flow coefficient, velocity distribution, and comparison of a variety of elbow ducts are provided.
Date: October 1941
Creator: McLellan, Charles H. & Bartlett, Walter A., Jr.
Partner: UNT Libraries Government Documents Department
open access

Methods of Analyzing Wind-Tunnel Data for Dynamic Flight Conditions

Description: "The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedra… more
Date: October 1941
Creator: Donlan, C. J. & Recant, I. G.
Partner: UNT Libraries Government Documents Department
open access

The Oscillating Wing With Aerodynamically Balanced Elevator

Description: "The two-dimensional problem of the oscillating wing with aerodynamically balanced elevator is treated in the manner that the wing is replaced by a plate with bends and stages and the airfoil section by a mean line consisting of one or more straights. The computed formulas and tables permit, on these premises, the prediction of the pressure distribution and of the aerodynamic reactions of oscillating elevators and tabs with any position of elevator hinge in respect to elevator leading edge" (p.… more
Date: October 1941
Creator: Küssner, H. G. & Schwartz, I.
Partner: UNT Libraries Government Documents Department
open access

The Selection of Propellers for High Thrust at Low Airspeed

Description: Problem of improving thrust at low speeds is primarily one of reducing angle of attack of operation of sections to improve L/D or reducing blade helix angle. An analysis, based on recent propeller data, is presented for determining improvements in thrust or efficiency which could be obtained by increased number of blades, increased blade width, increased diameter, dual rotation, and two-speed gearing. All methods were found very effective, particularly two-speed gearing.
Date: October 1941
Creator: Biermann, David & Conway, Robert N.
Partner: UNT Libraries Government Documents Department
open access

Statistical analysis of the time and fatigue strength of aircraft wing structures

Description: The results from stress measurements in flight operation afford data for analyzing the frequency of appearance of certain parts of the static breaking strength during a specified number of operating hours. Appropriate frequency evaluations furnish data for the prediction of the required strength under repeated stress in the wing structures of aircraft of the different stress categories for the specified number of operating hours demanded during the life of a component.
Date: October 1941
Creator: Kaul, Hans W.
Partner: UNT Libraries Government Documents Department
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