Experimental Investigation of a New Type of Low-Drag Wing-Nacelle Combination (open access)

Experimental Investigation of a New Type of Low-Drag Wing-Nacelle Combination

Report discusses the results of an experimental investigation of two low-drag wing-nacelle units suitable for use with pusher propellers. The benefits of adding a nacelle to the wing are detailed.
Date: July 1942
Creator: Allen, H. Julian & Frick, Charles W., Jr.
System: The UNT Digital Library
Tests of a Heated Low-Drag Airfoil (open access)

Tests of a Heated Low-Drag Airfoil

Report discusses the results of an experimental investigation into the NACA 65,2-016 heated wing. Information about the effect of heating on the drag coefficients, Reynolds numbers, and stability of the laminar boundary layer.
Date: December 1942
Creator: Frick, Charles W., Jr. & McCullough, George B.
System: The UNT Digital Library
A Profile-Drag Investigation in Flight on an Experimental Fighter-Type Airplane the North American XP-51 (open access)

A Profile-Drag Investigation in Flight on an Experimental Fighter-Type Airplane the North American XP-51

Report discussing the results of an investigation of the North American XP-51 and its low-drag airfoils. Several surface conditions were tested and the profile-drag coefficients were determined. The surface that was smoothened and faired by filling and sanding had the lowest profile-drag coefficient.
Date: November 1942
Creator: Zalovcik, John A.
System: The UNT Digital Library
Wind-Tunnel Investigation of Several Factors Affecting the Performance of a High-Speed Pursuit Airplane With Air-Cooled Radial Engine (open access)

Wind-Tunnel Investigation of Several Factors Affecting the Performance of a High-Speed Pursuit Airplane With Air-Cooled Radial Engine

Report details an investigation into various potential improvements and modifications to pursuit airplanes. NACA low-drag airfoil sections and their use for reducing drag and increasing compressibility speeds were examined. Other items covered include the propeller slipstream, high-speed cowling arrangement, and placement of wing guns.
Date: November 1941
Creator: Wenzinger, Carl J.
System: The UNT Digital Library
Model Tests of a Wing-Duct System for Auxiliary Air Supply (open access)

Model Tests of a Wing-Duct System for Auxiliary Air Supply

Report discusses the design of a cooling system developed for a Pratt & Whitney H-2800 engine equipped with a two-stage supercharger. The wing-duct system was newly developed and was determined to be a valuable method for cooling engine auxiliaries by combining simplicity with low drag and excellent cooling capabilities.
Date: January 1941
Creator: Bierman, David & Corson, Blake W., Jr.
System: The UNT Digital Library
The Effect of Streamlining the Afterbody of an N.A.C.A. Cowling (open access)

The Effect of Streamlining the Afterbody of an N.A.C.A. Cowling

"The drag and the power cost associated with the changing of the nose of a nacelle from a streamline shape to a conventional N.A.C.A. cowling shape was investigated in the N.A.C.A. 20-foot tunnel. Full-scale propellers and nacelles were used. The increment of drag associated with the change of nose shapes was found to be critically dependent on the afterbody of the nacelle" (p. 1).
Date: December 1939
Creator: Stickle, George W.; Crigler, John L. & Naiman, Irven
System: The UNT Digital Library
N.A.C.A. Stall-Warning Device (open access)

N.A.C.A. Stall-Warning Device

With some airplanes the approach to the stall is accompanied by changes in the behavior, such as tail buffeting or changes in the control characteristics of the airplane so that the pilot obtains a warning of the impending stall. Vith other airplanes it is possible to approach the stall without any perceptible warning other than the reading of the air-speed meter, in which case the danger of inadvertent stalling is considerably greater. Although it is not within the scope of this paper to discuss stalling characteristics, it is desired to point out that in general the danger of inadvertent stalling is greatest with those airplanes that behave worse when the stalling occurs; that is, with airplanes in which the stall starts at the wing tips. A warning of the impending stall is desirable in any case, but is particularly desirable with airplanes of the latter type.
Date: February 1938
Creator: Thompson, F. L.
System: The UNT Digital Library
The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers (open access)

The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers

An investigation has been made of the effect of aerodynamic heating on propeller-blade temperatures. The blade temperature rise resulting from aerodynamic heating was measured and the relation between the resulting blade temperatures and the outer limit of the iced-over region was examined. It was found that the outermost station at which ice formed on a propeller blade was determined by the blade temperature rise resulting from the aerodynamic heating at that point.
Date: August 1940
Creator: Rodert, Lewis A.
System: The UNT Digital Library
Interference of Tail Surfaces and Wing and Fuselage from Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel (open access)

Interference of Tail Surfaces and Wing and Fuselage from Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel

"An investigation of the interference associated with tail surfaces added to wing-fuselage combinations was included in the interference program in progress in the NACA variable-density tunnel. The results indicate that, in aerodynamically clean combinations, the increment to the high-speed drag can be estimated from section characteristics within useful limits of accuracy. The interference appears mainly as effects on the downwash angel and as losses in the tail" (p. 1).
Date: January 1939
Creator: Sherman, Albert
System: The UNT Digital Library
The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous Over Three Supports (open access)

The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous Over Three Supports

Report presenting a test of a long column continuous over three supports to determine its critical load when the center support was given varying amounts of initial displacement. During each test, the middle support was hinged so as to be free to move parallel to the column axis during buckling.
Date: November 1940
Creator: Lunquist, Eugene E. & Kotanchik, Joseph N.
System: The UNT Digital Library
High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane (open access)

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

"Force tests were made of a 1/8-scale model of a twin-engine low-wing transport airplane in the NACA 8-foot high-speed wind tunnel to investigate compressibility and interference effects at 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. The results show serious increases in drag at critical speeds below 450 miles per hour due to the occurrence of compressibility burbles on the standard radial-engine cowlings, on sections of the wing as a result of wing-nacelle interference, and on the semi-retracted main landing wheels" (p. 1).
Date: April 1940
Creator: Becker, John V. & Leonard, Lloyd H.
System: The UNT Digital Library
Mechanical Properties of Flush-Riveted Joints (open access)

Mechanical Properties of Flush-Riveted Joints

Report discusses the strength of several types of flush-riveted joints, including single-shearing, double-shearing, and tensile specimens. The stress at failure, type of failure, and d/t ratio are provided. Dimpled joints were found to be the strongest, but their strength was heavily influenced by the details of their construction.
Date: January 1940
Creator: Bruggeman, William C. & Roop, Frederick C.
System: The UNT Digital Library
Critical Compressive Stress for Outstanding Flanges (open access)

Critical Compressive Stress for Outstanding Flanges

"A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the Loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for the construction of the chart are given" (p. 1).
Date: April 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
System: The UNT Digital Library
Wind-Tunnel Investigation of an N.A.C.A. 23012 Airfoil with a Slotted Flap and Three Types of Auxiliary Flap (open access)

Wind-Tunnel Investigation of an N.A.C.A. 23012 Airfoil with a Slotted Flap and Three Types of Auxiliary Flap

"An investigation was made in the N.A.C.A. 7- by 10- foot wind tunnel to determine the aerodynamic section characteristics of an N. A. C. A. 23012 airfoil with a single main slotted flap equipped successively with auxiliary flaps of the plain, split, and slotted types. A test installation mas used in which an airfoil of 7-foot span was mounted vertically between the upper and the lower sides of the closed test section so that two-dimensional flow was approximated. On the basis of maximum lift coefficient, low drag at moderate and high lift coefficients, and high drag at high lift coefficients, the optimum combination of the arrangements was found to be the double slotted flap" (p. 1).
Date: December 1938
Creator: Wenzinger, Carl J. & Gauvain, William E.
System: The UNT Digital Library
Compressibility Effects in Aeronautical Engineering (open access)

Compressibility Effects in Aeronautical Engineering

"Compressible-flow research, while a relatively new field in aeronautics, is very old, dating back almost to the development of the first firearm. Over the last hundred years, researches have been conducted in the ballistics field, but these results have been of practically no use in aeronautical engineering because the phenomena that have been studied have been the more or less steady supersonic condition of flow. Some work that has been done in connection with steam turbines, particularly nozzle studies, has been of value, In general, however, understanding of compressible-flow phenomena has been very incomplete and permitted no real basis for the solution of aeronautical engineering problems in which.the flow is likely to be unsteady because regions of both subsonic and supersonic speeds may occur" (p. 1).
Date: August 1941
Creator: Stack, John
System: The UNT Digital Library
An Investigation of the Drag of Windshields in the 8-Foot High-Speed Wind Tunnel (open access)

An Investigation of the Drag of Windshields in the 8-Foot High-Speed Wind Tunnel

"The drag of closed-cockpit and transport-type windshields was determined from tests made at speeds from 200 to 440 miles per hour in the NACA 8-foot high-speed wind tunnel. This speed range corresponds to a test Reynolds number range of 2,510,000 to 4,830,000 based on the mean aerodynamic chord of the full-span model (17.29 inches). The shapes of the windshield proper, the hood, and the tail fairing were systematically varied to include common types and a refined design" (p. 1).
Date: June 1939
Creator: Robinson, Russell G. & Delano, James B.
System: The UNT Digital Library
The Calculated Effect of Various Hydrodynamic and Aerodynamic Factors on the Take-Off of a Large Flying Boat (open access)

The Calculated Effect of Various Hydrodynamic and Aerodynamic Factors on the Take-Off of a Large Flying Boat

Present designs for large flying boats are characterized by high wing loading, high aspect ratio, and low parasite drag. The high wing loading results in the universal use of flaps for reducing the takeoff and landing speeds. These factors have an effect on takeoff performance and influence to a certain extent the design of the hull. An investigation was made of the influence of various factors and design parameters on the takeoff performance of a hypothetical large flying boat by means of takeoff calculations.
Date: June 1939
Creator: Olson, R. E. & Allison, J. M.
System: The UNT Digital Library
Profile-Drag Investigation of an Airplane Wing Equipped with Rubber Inflatable De-Icer (open access)

Profile-Drag Investigation of an Airplane Wing Equipped with Rubber Inflatable De-Icer

"The National Advisory Committee for Aeronautics has made profile-drag measurements in flight of a wing which was equipped with a rubber inflatable de-icer and to which various stimulated ice formations were attached. Tuft observations at the stalling speed of the wing with the various drag conditions were made in order to determine the influence on the maximum lift coefficient. The de-icer installation caused an increase of from 10-20% in the profile drag of the plain wing and reduced CL(sub max) about 6%" (p. 1).
Date: December 1939
Creator: Rodert, Lewis A. & Jones, Alun R.
System: The UNT Digital Library
Preliminary Investigation of Certain Laminar-Flow Airfoils for Application at High Speeds and Reynolds Numbers (open access)

Preliminary Investigation of Certain Laminar-Flow Airfoils for Application at High Speeds and Reynolds Numbers

"In order to extend the useful range of Reynolds numbers of airfoils designed to take advantage of the extensive laminar boundary layers possible in an air stream of low turbulence, tests were made of the NACA 2412-34 and 1412-34 sections in the NACA low-turbulence tunnel. Although the possible extent of the laminar boundary layer on these airfoils is not so great as for specially designed laminar-flow airfoils, it is greater than that for conventional airfoils, and is sufficiently extensive so that at Reynolds numbers above 11,000,000 the laminar region is expected to be limited by the permissible 'Reynolds number run' and not by laminar separation as is the case with conventional airfoils" (p. 1).
Date: August 1939
Creator: Jacobs, E. N.; Abbott, Ira H. & von Doenhoff, A. E.
System: The UNT Digital Library
Radiator Design and Installation (open access)

Radiator Design and Installation

"The fundamental principles of fluid flow, pressure losses, and heat transfer have been presented and analyzed for the case of a smooth tube with fully developed turbulent flow. These equations apply to tubes with large length-diameter ratios where the flow is at a high Reynolds Number. The error introduced by using these equations increases as the magnitude of the tube length and the air-flow Reynolds Number approaches the values encountered in modern radiator designs" (p. 1).
Date: May 1939
Creator: Brevoort, M. J. & Leifer, M.
System: The UNT Digital Library
An Electrical-Type Indicating Fuel Flowmeter (open access)

An Electrical-Type Indicating Fuel Flowmeter

"An electrical-type meter has been developed for measuring mass rates of flow of gasoline or other nonconducting fluids. Its temperature dependence is small over a large range and it has no known vibrational or viscosity errors. The maximum temperature rise is less than 5 C. The rates of flow, measurable within 1% with the present instrument, are approximately 100 to 1,000 or more pounds of gasoline per hour when a potentiometer is used, or 100 to 300 pounds per hour when a deflection-type meter is used" (p. 1).
Date: September 1939
Creator: Tozier, Robert E.
System: The UNT Digital Library
Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report (open access)

Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report

"Two cowling systems intended to reduce the drag and improve the low-speed cooling characteristics of conventional radial engine cowlings were tested in model form to determine the practicability of the methods. One cowling included a blower mounted on the rear face of a large propeller spinner which drew cooling air in through side entrance ducts located behind the equivalent engine orifice plate. The air was passed through the equivalent engine orifice plate from rear to front and out through a slot between the spinner and the engine plate" (p. 1).
Date: July 1939
Creator: Biermann, David & Valentine, E. Floyd
System: The UNT Digital Library
Preliminary Tests of Blowers of Three Designs Operating in Conjunction with a Wing-Duct Cooling System for Radial Engines, Special Report (open access)

Preliminary Tests of Blowers of Three Designs Operating in Conjunction with a Wing-Duct Cooling System for Radial Engines, Special Report

"This paper is one of several dealing with methods intended to reduce the drag of present-day radial engine installations and improve the cooling at zero and low air speeds. The present paper describes model wind-tunnel tests of blowers of three designs tested in conjunction with a wing-nacelle combination. The principle of operation involved consists of drawing cooling air into ducts located in the wing root at the point of maximum slipstream velocity, passing the air through the engine baffles from rear to front, and exhausting the air through an annular slot located between the propeller and the engine with the aid of a blower mounted on the spinner" (p. 1).
Date: June 1939
Creator: Biermann, David & Valentine, E. Floyd
System: The UNT Digital Library
Experiments on the Recovery of Waste Heat in Cooling Ducts, Special Report (open access)

Experiments on the Recovery of Waste Heat in Cooling Ducts, Special Report

Tests have been conducted in the N.A.C.A. full-scale wind tunnel to investigate the partial recovery of the heat energy which is apparently wasted in the cooling of aircraft engines. The results indicate that if the radiator is located in an expanded duct, a part of the energy lost in cooling is recovered; however, the energy recovery is not of practical importance up to airplane speeds of 400 miles per hour. Throttling of the duct flow occurs with heated radiators and must be considered in designing the duct outlets from data obtained with cold radiators in the ducts.
Date: May 1939
Creator: Silverstein, Abe
System: The UNT Digital Library