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Cotton From Boll to Bale.

Description: Describes the steps for harvesting, drying, handling, baling, and storing cotton.
Date: October 1941
Creator: Gerdes, Francis L. (Francis Leo), 1907-; Martin, William J. (William Jules), 1910- & Bennett, Charles A. (Charles Abel), b. 1889
Partner: UNT Libraries Government Documents Department

Airplane structures.

Description: Describes structural details of service airplanes used by the Army Air Corps, sufficient for personnel to perform inspection and maintenance of their equipment.
Date: October 29, 1941
Creator: United States. War Department.
Partner: UNT Libraries Government Documents Department

Velocity gained and altitude lost in recoveries from inclined flight paths

Description: A series of charts is given showing the variation of the velocity gained and the altitude lost in dive pullouts with the initial indicated air speed and the dive angle. The effects of the maximum load factor, the drag parameter K, the initial altitude, and the type of recovery on the velocity gained and the altitude lost are also considered. The results were obtained from a step-by-step solution of the equations of motion in which mean values of the air density and the airplane drag coefficient were used. The load-factor variation with time is arbitrarily specified in various ways to simulate pull-out procedures, some of which might be encountered in flight.
Date: October 1941
Creator: Pearson, H. A. & Garvin, J. B.
Partner: UNT Libraries Government Documents Department

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

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. 1).
Date: October 1941
Creator: Küssner, H. G. & Schwartz, I.
Partner: UNT Libraries Government Documents Department

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 of constant-speed propellers, effect of solidity and dual rotation, effect of number of blades, and some peculiarities of four-blade propellers are provided.
Date: October 1941
Creator: Reid, Elliott G.
Partner: UNT Libraries Government Documents Department

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

Ground Effect on Downwash Angles and Wake Location

Description: "A theoretical study was made of the reduction in downwash and the upward displacement of the wake in the presence of the ground, and some verification of theory was obtained by means of air-flow measurements made with a ground-board and image-wing combination. Methods are given for estimating the effects and numerous examples are included to illustrate the nature of these effects and to show their order of magnitude" (p. 1).
Date: October 3, 1941
Creator: Katzoff, S. & Sweberg, Harold H.
Partner: UNT Libraries Government Documents Department

Normal-pressure tests of circular plates with clamped edges

Description: A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness form 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of the permanent set as a function of the dimensions of the plate and the tensile properties of the material.
Date: October 10, 1941
Creator: McPherson, Albert E.; Ramberg, Walter & Levy, Samuel
Partner: UNT Libraries Government Documents Department

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

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 500 mph at 20,000 ft altitude" (p. 1).
Date: October 1941
Creator: Silverstein, Abe & Guryansky, Eugene R.
Partner: UNT Libraries Government Documents Department

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

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

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

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

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

A study of the effects of vertical tail area and dihedral on the lateral maneuverability of an airplane

Description: Report presenting a theoretical investigation of the influence of changes in vertical tail area and dihedral angle on the lateral flying characteristics of an airplane. Lateral motions were computed for nine different combinations of vertical tail area and dihedral. Results regarding the lateral motions due to applied rolling moment with different amounts of accompanying pawing moment and lateral motions due to applied yawing moment are provided.
Date: October 1941
Creator: Fehlner, Leo F.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of an NACA 23012 airfoil with an 18.05 percent chord Maxwell slat and with trailing-edge flaps

Description: Report presenting an investigation in the 7- by 10-foot wind tunnel of an NACA 23012 airfoil with an 18.05-percent-chord Maxwell leading-edge slat and with a slotted and a split flap. The main purpose of the investigation was to determine the optimum slot gap of the Maxwell slat for, and the aerodynamic section characteristics of, the airfoil with several deflections of both types of flap.
Date: October 1941
Creator: McKee, John W.
Partner: UNT Libraries Government Documents Department

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 circular cross section in an elliptical cylinder. Experiments showed that the piston is normally eccentric in the cylinder. The pistons tested were 1.25 and 2 inches in diameter 0.062 to 1.00 inch long, and the clearances varied from 1.36 to 5.16 x 10 to the 3rd power inch. The difference in pressure on the two sides of the piston varied from about 2 to 55 pounds per square inch. The piston velocities for each assembly were measured with damping liquids of three different viscosities. At high piston velocities, when turbulent flow exists, the observed velocities were much lower than the velocities calculated on the basis of laminar flow. Results for a wide range of Reynolds numbers are presented in graphical form.
Date: October 1941
Creator: Peterson, John B.
Partner: UNT Libraries Government Documents Department

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 dihedral and fin area" (p. 1).
Date: October 1941
Creator: Donlan, C. J. & Recant, I. G.
Partner: UNT Libraries Government Documents Department