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Longitudinal Stability in Relation to the Use of an Automatic Pilot

Description: "The effect of restraint in pitching introduced by an automatic pilot upon the longitudinal stability of an airplane has been studied. Customary simplifying assumptions have been made in setting down the equations of motion, and the results of computations based on the simplified equations are presented to show the effect of an automatic pilot installed in an airplane of known dimensions and characteristics. The equations developed have been applied by making calculations for a Clark biplane and a Fairchild 22 monoplane" (p. 1).
Date: September 1938
Creator: Klemin, Alexander; Pepper, Perry A. & Wittner, Howard A.
Partner: UNT Libraries Government Documents Department

Interference of Wing and Fuselage From Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel Combination With Special Junctures

Description: "As part of the wing-fuselage interference program in progress in the NACA variable-density wind tunnel, a method of eliminating the interference bubble associated with critical mid wing combinations was investigated. The interference bubble of the critical mid wing combination was shown to respond to modification at the nose of the juncture and to be entirely suppressed with little or no adverse effect on the high-speed drag by special leading edge fillets" (p. 1).
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department

Interference of Wing and Fuselage From Tests of the 18 Combinations in the N.A.C.A. Variable-Density Tunnel - Combination With Split Flaps

Description: "As part of the wing-fuselage interference investigation in progress in the N.A.C.A. variable density wind tunnel, the effects of various split-flap arrangements applied to wing-fuselage combinations were determined. Split flaps were found to exert their influence independently of the interference, and their effects on the aerodynamic characteristics of rectangular-airfoil combinations appeared to be more or less proportional to their exposed span lengths. The interference, moreover, showed the same character with the split flaps as without them" (p. 1).
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department

Interference of Wing and Fuselage From Tests of Eight Combinations in the N.A.C.A. Variable-Density Tunnel Combinations With Tapered Fillets and Straight-Side Junctures

Description: "The round fuselage of an unfilleted low-wing combination was modified to incorporate straight-side junctures. The resulting combination, with or without horizontal tail surfaces, had practically the same aerodynamic characteristics as the corresponding round-fuselage tapered-fillet combination" (p. 1).
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department

Noise From Propellers With Symmetrical Sections at Zero Blade Angle, 2

Description: "In a previous paper (Technical Note No. 605), a theory was developed that required an empirical relation to calculate sound pressures for the higher harmonics. Further investigation indicated that the modified theory agrees with experiment and that the empirical relation was due to an interference phenomenon peculiar to the test arrangement used. Comparison is made between the test results for a two-blade arrangement and the theory" (p. 1).
Date: December 1938
Creator: Deming, A. F.
Partner: UNT Libraries Government Documents Department

Preliminary Fatigue Studies on Aluminum Alloy Aircraft Engines

Description: "Preliminary information on the complex subject of the fatigue strength of fabricated structural members for aircraft is presented in the test results obtained on several different types of airship girders subjected to axial tension and compression in a resonance fatigue machine. A description of this machine as well as numerous photographs of the fatigue failures are given. There is also presented an extended bibliography on the subject of fatigue strength" (p. 1).
Date: February 1938
Creator: Goodyear-Zeppelin Corporation
Partner: UNT Libraries Government Documents Department

Tests of N-85, N-86 and N-87 Airfoil Sections in the 11-Inch High Speed Wind Tunnel

Description: "Three airfoils, the N-85, the N-86, and the N-87, were tested at the request of the Bureau of Aeronautics, Navy Department, to determine the suitability of these sections for use as propeller-blade sections. Further tests of the NACA 0009-64 airfoil were also made to measure the aerodynamic effect of thickening the trailing edge in accordance with current propeller practice. The N-86 and the N-87 airfoils appear to be nearly equivalent aerodynamically and both are superior to the N-85 airfoil" (p. 1).
Date: September 1938
Creator: Stack, John & Lindsey, W. F.
Partner: UNT Libraries Government Documents Department

Tests of a Contra-Propeller for Aircraft

Description: "Tests of an 8-blade contra-propeller of 32-inch diameter in combination with a 4-inch, 36-inch diameter adjustable pitch, metal propeller at pitch setting of 15, 25, 35, and 45 degrees at 0.75 R were made. The tests showed a significant increase in effective thrust of the combination over that of the propeller alone for value V/nD somewhat below those for maximum efficiency and without a corresponding increase of power absorbed. From 1/2 percent to 2-1/2 percent in propulsive efficiency was thus gained in this range" (p. 1).
Date: November 1938
Creator: Benson, William M.
Partner: UNT Libraries Government Documents Department

Generalized Analysis of Experimental Observations in Problems of Elastic Stability

Description: "A generalized method of analyzing experimental observations in problems of elastic stability is presented in which the initial readings of load and deflection may be taken at any load less the critical load. The analysis is an extension of a method published by Southwell in 1932, in which it was assumed that the initial readings are taken at zero load" (p. 1).
Date: July 1938
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department

Fatigue Testing of Wing Beam by the Resonance Method

Description: "Preliminary fatigue tests on two aluminum-alloy wing-beam specimens subjected to reversed axial loading are described. The motion used consists in incorporating one or two reciprocating motors in a resonance system of which the specimen is the spring element. A description is given of the reciprocating motors, and of the method of assembling and adjusting the vibrating system" (p. 1).
Date: August 1938
Creator: Bleakney, William M.
Partner: UNT Libraries Government Documents Department

A study of flying-boat take-off

Description: It is shown that the normal resistance curve for a flying boat may be approximated by two straight lines. The equations for take-off distance and time, derived from this approximation, are applied to a series of flying boats and the resulting factors are plotted in non dimensional form in a series of charts. Take-off performances from the charts are shown to be in good agreement with step-by-step integrations. Some applications of the charts to the solution of general design problems are included.
Date: April 1938
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department

The increase in frictional resistance caused by various types of rivet heads as determined by tests of planing surfaces

Description: "The increase in the frictional resistance of a surface caused by the presence of rivet heads was determined by towing four planing surfaces of the same dimensions. One surface was smooth and represented a surface without rivet heads or one with perfectly flush countersunk rivets. The other three surfaces were each fitted with the same number of full-size rivet heads but of a different type arranged in the same pattern on each surface" (p. 1).
Date: May 1938
Creator: Truscott, Starr & Parkinson, J. B.
Partner: UNT Libraries Government Documents Department

Hydrodynamic and aerodynamic tests of models of flying-boat hulls designed flow aerodynamic drag - NACA models 74, 74-A, and 75

Description: The present tests illustrate how the aerodynamic drag of a flying boat hull may be reduced by following closely the form of a low drag aerodynamic body and the manner in which the extent of the aerodynamic refinement is limited by poorer hydrodynamic performance. This limit is not sharply defined but is first evidenced by an abnormal flow of water over certain parts of the form accompanied by a sharp increase in resistance. In the case of models 74-A and 75, the resistance (sticking) occurs only at certain combinations of speed, load, and trim and can be avoided by proper control of the trim at high water speeds.
Date: October 1938
Creator: Truscott, Starr; Parkinson, J. B.; Ebert, John W., Jr. & Valentine, E. Floyd
Partner: UNT Libraries Government Documents Department

Tank Tests to Show the Effect Rivet Heads on the Water Performance of a Seaplane-Float

Description: "A 1/3.5 full-sized model of a seaplane float constructed from lines supplied by the Bureau of Aeronautics, Navy Department, was tested first with smooth painted bottom surfaces and then with round-head rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. A percentage increase in water resistance caused by the added roughness was found to be from 5 to 20 percent at the hump speed and from 15 to 40 percent at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high trims" (p. 1).
Date: July 1938
Creator: Parkinson, J. B.
Partner: UNT Libraries Government Documents Department

Engine performance and knock rating of fuels for high-output aircraft engines

Description: From Summary: "Data are presented to show the effects of inlet-air pressure, inlet-air temperature, and compression ratio on the maximum permissible performance obtained on a single-cylinder test engine with aircraft-engine fuels varying from a fuel of 87 octane number to one 100 octane number plus 1 ml of tetraethyl lead per gallon. The data were obtained on a 5-inch by 5.75-inch liquid-cooled engine operating at 2,500 r.p.m. The compression ratio was varied from 6.50 to 8.75. The inlet-air temperature was varied from 120 to 280 F and the inlet-air pressure from 30 inches of mercury absolute to the highest permissible."
Date: April 1938
Creator: Rothrock, A. M. & Biermann, Arnold E.
Partner: UNT Libraries Government Documents Department

Tables of Stiffness and Carry-Over Factor for Structural Members Under Axial Load

Description: "Tables of stiffness and carry-over factor are presented for members in which the cross section and axial load do not vary along the length of the member. These tables are of use in solving problems in the stability of structural members under axial load as well as in application of the Cross method of moment distribution when the effects of axial load in the members are considered. The interval between successive values of the argument is small enough to make interpolation unnecessary in engineering calculations" (p. 1).
Date: June 1938
Creator: Lundquist, Eugene E. & Kroll, W. D.
Partner: UNT Libraries Government Documents Department

Scavenging a Piston-Ported Two-Stroke Cylinder

Description: "An investigation was made with a specially designed engine to determine the scavenging characteristics of a large number of inlet-port shapes and arrangements and the optimum port arrangement and timing for this particular type of engine. A special cylinder construction permitted wide variations in timing for this particular type of engine. A special cylinder construction permitted wide variations in timing as well as in shape and arrangement of both the inlet and exhaust ports" (p. 1).
Date: November 1938
Creator: Rogowski, A. R. & Bouchard, C. L.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Tests of a 2-Engine Airplane Model as a Preliminary Study of Flight Conditions Arising on the Failure of the Engine

Description: "Wind tunnel tests of a 15-foot-span model of a two-engine low wing transport airplane were made as a preliminary study of the emergency arising from the failure of one engine in flight. Two methods of reducing the initial yawing moment resulting from the failure of one engine were investigated and the equilibrium conditions were explored for two basic modes on one engine, one with zero angle of sideslip and the other with several degrees of sideslip. The added drag resulting from the unsymmetrical attitudes required for flight on one engine was determined for the model airplane" (p. 1).
Date: April 1938
Creator: Hartman, Edwin P.
Partner: UNT Libraries Government Documents Department

Tank Tests of Model 36 Flying Boat Hull

Description: "N.A.C.A. Model 36, a hull form with parallel middle body for half the length of the forebody and designed particularly for use with stub wings, was tested according to the general fixed-trim method over the range of practical loads, trims, and speeds. It was also tested free to trim with the center of gravity at two different positions. The results are given in the form of nondimensional coefficients. The resistance at the hump was exceptionally low but, at high planing speeds, afterbody interference made the performance only mediocre" (p. 1).
Date: March 1938
Creator: Allison, John M.
Partner: UNT Libraries Government Documents Department

Fuel Consumption of a Carburetor Engine at Various Speeds and Torques

Description: "An investigation was conducted to obtain fuel-consumption curves for a single-cylinder engine with a Wright 1820-G and Pratt & Whitney 1340-H cylinder at varying speeds, manifold pressures, and air-fuel ratios. The 1340- H cylinder was tested at speeds from 1,200 to 2,400 r.p.m. and at manifold pressures from 21 to 38 inches of mercury absolute. Less than extensive tests were made of the 1820-G cylinder. The results of the tests showed that the minimum brake fuel consumption was obtained when the engines were operating at high torques and at speeds from 60 to 70 percent of the rated speed" (p. 1).
Date: June 1938
Creator: Schey, Oscar W. & Clark, J. Denny
Partner: UNT Libraries Government Documents Department

The Pressure Available for Ground Cooling in Front of the Cowling of Air-Cooled Airplane Engines

Description: "A study was made of the factors affecting the pressure available for ground cooling in front of a cowling. Most of the results presented were obtained with a set-up that was about one-third full scale. A number of isolated tests on four full-scale airplanes were made to determine the general applicability of the model results. The full-scale tests indicated that the model results may be applied qualitatively to full-scale design and quantitatively as a first approximation of the front pressure available for ground cooling" (p. 1).
Date: November 1938
Creator: Stickle, George W. & Joyner, Upshur T.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel of Three Lateral-Control Devices in Combination With a Full-Span Slotted Flap on an NACA 23012 Airfoil

Description: "A large-chord NACA 23012 airfoil was tested. The airfoil extended completely across the test section, and two-dimensional flow was approximated. The model was fitted with a full-span slotted flap having a chord 25.66 percent of the airfoil chord. The ailerons investigated extended over the entire span and each had a chord 10 percent of the airfoil chord" (p. 1).
Date: August 1938
Creator: Wenzinger, Carl J. & Bamber, Millard J.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Tests of a Clark Y Wing Having Split Flaps With Gaps

Description: "Tests were made of the Clark Y wing having split flaps with a gap between the flap and the lower surface of the wing. Lift, drag, and pitching moments were measured for the wing with three different sizes of flap. It was found that any gap between the flap and the wing reduced the lift, the drag, and the pitching moments, but that the center-of-pressure movement and the ratio of lift to drag were little affected" (p. 1).
Date: May 1938
Creator: Wenzinger, Carl J.
Partner: UNT Libraries Government Documents Department