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Full-Scale-Tunnel Investigation of a Multiengine Pusher-Propeller Installation

Description: Report presenting an investigation of propellers designed specifically for pusher operation behind fixed contravanes on a large-scale model of a four-engine airplane. In the test, the wing trailing edge was twisted to serve as a contravane and to produce the rotating inflow required for optimum propulsive efficiency. Results indicated that gains in efficiency of about 3.5 percent at a blade angle of 40 degrees can be obtained by the use of contravanes with specifically designed pusher propeller… more
Date: November 1942
Creator: Wilson, Herbert A., Jr.
open access

Full-Scale Tunnel Investigation of the Control and Stability of a Twin-Engine Monoplane With Propellers Operating

Description: Report presenting extensive force tests covering a wide range of propeller thrust coefficients on a typical twin-engine tractor monoplane model with the horizontal tail surface removed and attached. Measurements were made with flaps retracted and deflected at various angles of attack with different stabilizer and elevator settings. Results regarding the effect of propeller operation on wing-fuselage combination and forces and air flow at tail are provided.
Date: November 1942
Creator: Sweberg, Harold H.
open access

Full-scale wind-tunnel and flight tests of a Fairchild XR2K-1 airplane with a zap flap and upper-surface aileron-wing installation

Description: Report presenting testing of a Fairchild XR2K-1 airplane equipped with a wing having a full-span Zap flap and upper-surface ailerons in the full-scale wind tunnel and in flight to determine the characteristics of the flap and ailerons. Results regarding the lift, drag, and pitching-moment coefficients of the airplane and the aileron rolling, yawing, and hinge-moment coefficients were measured at various flap deflections are provided. Maximum rolling velocity and acceleration, yawing velocity, t… more
Date: March 1942
Creator: Clousing, L. A.; Lehr, Robert R. & O'Sullivan, William J.
open access

Generalized equations for selection charts for heat exchangers in aircraft

Description: "The equations that describe the operation of a heat exchanger - the equations for pressure drop, rate of heat transfer, and power expenditure - have been put into nondimensional, generalized form. These generalized equations can be used for constructing selection charts for various types of aircraft heat exchangers. Such charts would facilitate choice of heat-exchanger dimensions for any given set of operating conditions. A typical selection chart is presented" (p. 1).
Date: April 1942
Creator: Tifford, Arthur N. & Wood, George P.
open access

Generalized selection charts for bombers powered by one, two, four, and six 2000-horsepower engines

Description: Report presenting a study of the performance of bombers powered by one, two, four, and six 2000-horsepower engines supercharged to 25,000 feet. The performances are computed and are based on drag coefficients equal to the best obtained on modern airplanes and on weight estimates obtained from modern Army Air Forces airplanes. A chart is provided with the coordinates of power loading and wing loading noted so that all performances can be compared.
Date: July 1942
Creator: Brevoort, M. J.; Stickle, G. W. & Hill, Paul R.
open access

Generalized selection charts for bombers powered by one, two, four, and six 3000-horsepower engines 1: capacity and economy

Description: Supplement using data from a previous report to show the cargo that can be carried at various ranges, pounds of cargo that can be carried per pound of fuel, and other graphs to simplify the problem of determining which cargo can be carried at any range. The assumptions, parameters, and equations from the original report are carried over in the supplement.
Date: August 1942
Creator: Brevoort, Maurice J.; Stickle, George W. & Hill, Paul R.
open access

Generalized selection charts for bombers powered by two, four, and six 3000-horsepower engines

Description: Report presenting a study of the performance of bombers powered by two, four, and six 3000-horsepower engines supercharged to 35,000 feet. The performances are computed and are based on drag coefficients equal to the best obtained on modern airplanes and on weight estimates obtained from modern Army Air Forces airplanes. A chart is provided with the coordinates of power loading and wing loading noted so that all performances can be compared.
Date: August 1942
Creator: Brevoort, Maurice J.; Stickle, George W. & Hill, Paul R.
open access

Generalized selection charts for bombers with four 2000-horsepower engines

Description: Report presenting a study of the performance of bombers powered by four 2000-horsepower engines supercharged to 25,000 feet. A series of charts is provided with the coordinates of power loading and wing loading in order to simplify the selection of the best airplane for a given purpose.
Date: May 1942
Creator: Brevoort, Maurice J.; Stickle, George W. & Hill, Paul R.
open access

Graphical representation of intercooler parameters and performance at altitudes from 25,000 to 60,000 feet

Description: From Summary: "Interdependence of intercooler parameters and performance for a pursuit-type airplane using a 1675-horsepower engine is shown at altitudes of 25,000, 36,000, 47,000, and 60,000 feet by means of perspective drawings. Qualitatively, the drawings have general application. Intercooling between stages of supercharging at high altitudes results in no saving in the power to supercharge and cool the engine air."
Date: November 1942
Creator: Brimley, D. E.
open access

Ground Effect on Downwash Angles and Wake Location

Description: "A theoretical study has been made of the reduction in downwash and upward displacement of the wake in the presence of the ground, and some verification of the theory has been 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: May 1942
Creator: Katzoff, S. & Sweberg, Harold H.
open access

Heat Transfer in the Turbulent Boundary Layer of a Compressible Gas at High Speeds

Description: "The Reynolds law of heat transfer from a wall to a turbulent stream is extended to the case of flow of a compressible gas at high speeds. The analysis is based on the modern theory of the turbulent boundary layer with laminar sublayer. The investigation is carried out for the case of a plate situated in a parallel stream. The results are obtained independently of the velocity distribution in the turbulent boundar layer" (p. 1).
Date: October 1942
Creator: Frankl, F. & Voishel, V.
open access

High-Speed Tests of a Ducted Body with Various Air-Outlet Openings

Description: Test of a ducted body with Internal flow were made in the 8-foot high-speed wind tunnel for the purpose of studying the effects on external drag and an critical speed of the addition of efficient inlet and outlet openings to a basic streamline shape. Drag tests of a 13.6- inch-diameter streamline body of fineness ratio 6.14 were made at Mach numbers ranging from 0.20 to 0.75. The model was centrally mounted on a 9-percent-thick airfoil and was designed to have an efficient airfoil-body juncture… more
Date: May 1942
Creator: Becker, John V. & Baals, Donald D.
open access

High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane

Description: Report presents the results of force tests made of a 1/8-scale model of a twin-engine low-wing transport airplane in the NACA 8-foot high-speed tunnel to investigate compressibility and interference effects of speeds up to 450 miles per hour. In addition to tests of the standard arrangement of the model, tests were made with several modifications designed to reduce the drag and to increase the critical speed.
Date: 1942
Creator: Becker, John V. & Leonard, Lloyd H.
open access

High-speed tests of radial-engine nacelles on a thick low-drag wing

Description: Report presenting testing in the high-speed wind tunnel to determine the drag characteristics of several types of radial-engine nacelle on a low-drag airfoil. The drag coefficients of nacelles incorporating cowling-nose shapes shown by previous tests to be efficient and afterbodies of adequate length were about the same magnitude as commonly obtained for comparable installations on conventional wings. Results regarding the reduction of data, effect of nacelles on lift, and pressures at wing-nac… more
Date: May 1942
Creator: Becker, John V.
open access

High-Speed Wind-Tunnel Tests of a 1/6-Scale Model of a Twin-Engine Pursuit Airplane

Description: Report presenting testing of a scale model of a twin-engine pursuit airplane in order to investigate the possibility of high-speed diving difficulties and to find remedies for them. Most of the data were obtained in force tests, although some pressure-distribution measurements, elevator hinge moments, and wake surveys were also made. The tests showed that the airplane will experience serious diving moments above lift coefficients of 0.5 at a Mach number of 0.65, and 0.1 at a Mach number of 0.72… more
Date: December 1942
Creator: Ganzer, Victor M.
open access

High-Speed Wind-Tunnel Tests of Gun Openings in the Nose of the Fuselage of a 1/4-Scale Model

Description: "In connection with recent tests of a 1/4-scale model pursuit airplane in the NACA 8-foot high-speed tunnel, gun openings having low drag were developed for installation in the nose of the fuselage. The increase in the fuselage-drag coefficient for the final form of openings was 0.0132 at a Mach number of 0.69 and at an angle of attack of 0 degrees. The corresponding drag coefficient based on the wing area was about 0.0005. The critical speed of the airplane was not affected by the gun openings… more
Date: July 1942
Creator: Fedziuk, Henry A.
open access

The Icing of Aircraft

Description: This technical memorandum presents a theoretical study of the processes accompanying the formation of ice on solid bodies. It discusses vapor pressure and sublimation in two air masses separated by a boundary area.
Date: September 1942
Creator: Robitzsch, M.
open access

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only… more
Date: November 14, 1942
Creator: Miller, Cearcy D. & Olsen, H. Lowell
open access

Improvement of Fatigue Life of an Aluminum Alloy by Overstressing

Description: "Fatigue tests were made on some 1.375-inch-diameter and 0.300-inch diameter specimens of a 17S-T aluminum alloy rod. One test of a large specimen was run continuously to failure at a maximum stress of 22,000 pounds per square inch. In two other tests of large specimens, thin surface layers were removed periodically until failure occurred. The same nominal maximum stress of 22,000 pounds per square inch was used throughout the two tests and the load on the fatigue machine was lowered accordingl… more
Date: August 1942
Creator: Stickley, G. W.
open access

The Influence of Bulkhead Spacing on Bending Stresses Due to Torsion

Description: Report presenting the reasons for the existence of bending stresses due to torsion and the theoretical formulas applying to rectangular boxes with finite bulkhead spacing. Tests are described which were made to verify the theory, strains being measured on a rectangular torsion box with four bulkhead spacings. Results regarding normal stresses are provided.
Date: May 1942
Creator: Kuhn, Paul
open access

The Influence of Impact Velocity on the Tensile Characteristics of Some Aircraft Metals and Alloys

Description: Note presenting the results of tension tests on sixteen metals and alloys, most of which are employed extensively in aircraft construction. The tension characteristics are discussed for static conditions and rates of deformation up to about 150 feet per second. An investigation of the effect of decreasing the gage length of specimens below 1 inch is reported.
Date: October 1942
Creator: Clark, Donald S.
open access

Interference effects of longitudinal flat plates on low-drag airfoils

Description: Three airfoils were tested with an intersecting flat plate normal to the span as a preliminary study of interference effects on airfoils. Small interference effects were noted on the first two airfoils, while larger effects were noted on the NACA 66,2-422 section, which had previously been shown to be unconservative with respect to separation. Airfoils known to be conservative should be used for inboard sections subject to nacelle and fuselage interference.
Date: November 1942
Creator: Abbott, Ira H.
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