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Experiments on Drag of Revolving Disks, Cylinders and Streamline Rods at High Speeds

Description: Report presenting an experimental investigation concerned primarily with the extension of test data on the drag of revolving disks, cylinders, and streamline rods to high Mach numbers and Reynolds numbers. The tests generally confirm earlier theories and add in some new results. One of the primary findings of interest is that skin friction does not depend on Mach number.
Date: June 1944
Creator: Theodorsen, Theodore & Regier, Arthur
Partner: UNT Libraries Government Documents Department
open access

NACA Mach number indicator for use in high-speed tunnels

Description: Report presenting a description of a device for indicating stream Mach number in a high-speed tunnel. It consists of a mechanism for determining the pressure ratio that Mach number is a function of. The instrument is in service in the 8-foot high-speed tunnel and its accuracy has been found adequate for wind-tunnel requirements.
Date: July 1943
Creator: Smith, Norman F.
Partner: UNT Libraries Government Documents Department
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Profile-Drag Coefficients of Conventional and Low-Drag Airfoils as Obtained in Flight

Description: "The results of flight investigations of the profile drag of several carefully finished conventional and low-drag airfoils are presented. The results indicated that in all cases lower profile-drag coefficients were obtained with the low-drag than with the conventional airfoils over the range of lift coefficient tested and that, for comparable conditions of lift coefficient and Reynolds number, the low-drag airfoils may have profile-drag coefficients which are at least 27 percent lower than the … more
Date: May 1944
Creator: Zalovcik, John A.
Partner: UNT Libraries Government Documents Department
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The development and application of high-critical-speed nose inlets

Description: From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was underta… more
Date: July 1945
Creator: Baals, Donald D.; Smith, Norman F. & Wright, John B.
Partner: UNT Libraries Government Documents Department
open access

On the Flow of a Compressible Fluid by the Hodography Method 1: Unification and Extension of Present-Day Results

Description: Report presenting elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison in the form of velocity correction formulas, of corresponding compressible and incompressible flows.
Date: March 1944
Creator: Garrick, I. E. & Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

A Concise Theoretical Method for Profile-Drag Calculation; Advance Report

Description: In this report a method is presented for the calculation of the profile drag of airfoil sections. The method requlres only a knowledge of the theoretical velocity distribution and can be applied readily once this dlstribution is ascertained. Comparison of calculated and experimental drag characteristics for several airfoils shows a satisfactory agreement. Sample calculatlons are included.
Date: February 1944
Creator: Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department
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Determination of General Relations for the Behavior of Turbulent Boundary Layers

Description: Report presenting an analysis of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. Results indicate that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter.
Date: July 1943
Creator: von Doenhoff, Albert E. & Tetervin, Neal
Partner: UNT Libraries Government Documents Department
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Performance of an exhaust-gas "blowdown" turbine on a nine-cylinder radial engine

Description: Report presenting tests on an exhaust-gas turbine with four separate nozzle boxes each covering a 90 degree arc of the nozzle diaphragm and each connected to a pair of adjacent cylinders in a Pratt & Whitney R-1340-12 nine-cylinder radial engine. Results regarding the power output of the engine and turbine, effect of the turbine on engine power, turbine power output and speed characteristics, mean turbine efficiency, effect of the blowdown turbine on exhaust-gas temperature, and condition of th… more
Date: December 1944
Creator: Turner, L. Richard & Desmon, Leland G.
Partner: UNT Libraries Government Documents Department
open access

The Propeller and Cooling-Air-Flow Characteristics of a Twin-Engine Airplane Model Equipped With NACA D(Sub S)-Type Cowlings and With Propellers of NACA 16-Series Airfoil Sections

Description: Report presenting an investigation in the 19-foot pressure tunnel to determine the nacelle drag, the cowling-air flow, and the propeller characteristics of a model of a high-performance military airplane. The model is fitted with NACA D(sub S)-type engine cowlings and with propellers embodying NACA 16-series airfoil sections. Results regarding the propeller characteristics, drag and cowling-air flow with the propeller removed, the effect of propeller on flow through cowling, and the influence o… more
Date: September 1944
Creator: McHugh, James G. & Pepper, Edward
Partner: UNT Libraries Government Documents Department
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On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation

Description: Report presenting the utilization of the differential equation of Chaplygin's jet problem to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows.
Date: November 1944
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

NACA Investigation of a Jet-Propulsion System Applicable to Flight

Description: "Following a brief history of the NACA investigation of jet-propulsion, a discussion is given of the general investigation and analyses leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight-performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at … more
Date: April 1944
Creator: Brown, Clinton E.
Partner: UNT Libraries Government Documents Department
open access

Notes on the Effect of Surface Distortions on the Drag and Critical Mach Number of Airfoils

Description: "The effect of two-dimensional bumps and surface waviness on the pressure distribution over airfoils is considered. It is shown that the results of the analysis may be useful in evaluating the effects of accidental or intended surface distortions on the drag and critical Mach number of airfoils" (p. 1).
Date: September 1943
Creator: Allen, H. Julian
Partner: UNT Libraries Government Documents Department
open access

Effects of Specific Types of Surface Roughness on Boundary-Layer Transition

Description: Report presenting tests of two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils.
Date: February 1946
Creator: Loftin, Laurence K., Jr.
Partner: UNT Libraries Government Documents Department
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A study of the application of data on various types of flap to the design of fighter brakes

Description: Report presenting an approximate method of applying the available data on various types of flaps in the design of fighter brakes together with several examples of its use. The computed effects of flap type, size, location, and deflection as well as the effects of altitude and initial velocities on braking characteristics are also shown in some examples using the method to determine various flap arrangements.
Date: June 1942
Creator: Purser, Paul E.
Partner: UNT Libraries Government Documents Department
open access

Effect of a Trailing-Edge Extension on the Characteristics of a Propeller Section

Description: Report presenting a convenient technical method to evaluate changes in the airfoil characteristics resulting from an extension of the chord at the trailing edge of a propeller blade section. The method determines the change in the angle of zero lift, the ideal angle of attack, and the difference in these angles as a function of the angle and length of the trailing-edge extension.
Date: September 1944
Creator: Theodorsen, Theodore & Stickle, George W.
Partner: UNT Libraries Government Documents Department
open access

Variation of peak pitching-moment coefficients for six airfoils as affected by compressibility

Description: Report presenting pressure distribution tests of six NACA 16-series propeller sections with 1-foot chords in the 8-foot high-speed tunnel to determine the compressibility effects on peak section pitching-moment coefficients. Data is presented as curves of peak section pitching-moment coefficient against Mach number, thickness ratio, and camber. The peak pitching-moment coefficients were found to occur in the regions of positive and negative stall.
Date: October 1944
Creator: Cleary, Harold E.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of control-surface characteristics 17: beveled-trailing-edge flaps of 0.20, 0.30, and 0.40 airfoil chord on an NACA 0009 airfoil

Description: Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 0009 airfoil with flaps having chord at 3 locations of the airfoil chord and three degrees of the beveled trailing edges. The results indicated that, with a smooth leading edge, the increased trailing-edge angle on the flaps with sealed gaps decreased the slope of the control-fixed lift curve and the lift effectiveness.
Date: April 1944
Creator: Lockwood, Vernard E.
Partner: UNT Libraries Government Documents Department
open access

Effects of Compressibility on the Maximum Lift Characteristics and Spanwise Load Distribution of a 12-Foot-Span Fighter-Type Wing of NACA 230-Series Airfoil Sections

Description: Lift characteristics and pressure distribution for a NACA 230 wing were investigated for an angle of attack range of from -10 to +24 degrees and Mach range of from 0.2 to 0.7. Maximum lift coefficient increased up to a Mach number of 0.3, decreased rapidly to a Mach number of 0.55, and then decreased moderately. At high speeds, maximum lift coefficient was reached at from 10 to 12 degrees beyond the stalling angle. In high-speed stalls, resultant load underwent a moderate shift outward.
Date: November 1945
Creator: Pearson, E. O., Jr.; Evans, A. J. & West, F. E., Jr.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of Control-Surface Characteristics 15: Various Contour Modifications of a 0.30-Airfoil-Chord Plain Flap on an NACA 66(215)-014 Airfoil

Description: Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 66(215)-014 airfoil equipped with true-contour, straight-contour, and beveled-trailing-edge flaps with chords 30 percent of the airfoil chord. The results are presented in the form of aerodynamic section characteristics for several flap deflections and for a sealed and unsealed gap at the flap nose.
Date: December 1943
Creator: Purser, Paul E. & Riebe, John M.
Partner: UNT Libraries Government Documents Department
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Wind-Tunnel Investigation of an NACA 23021 Airfoil With Two Sizes of Balanced Split Flaps

Description: Report presenting an investigation in the 7- by 10-foot wind tunnel of a large-chord NACA 23021 airfoil with a 15-percent-chord and a 25-percent-chord balanced split flap of Clark Y profile, to determine the aerodynamic section characteristics of the airfoil-flap combinations as affected by the size, nose location, and deflection of the flaps.
Date: February 1941
Creator: Swanson, Robert S. & Schuldenfrei, Marvin J.
Partner: UNT Libraries Government Documents Department
open access

Preliminary Report on the Characteristics of the N.A.C.A. 4400R Series Airfoils

Description: Report presenting tests made in the variable-density wind tunnel of airfoils of the NACA 4400 series modified by reflex at the trailing edge designed to reduce the pitching moment to the value of -0.03. The modified airfoils are designated the NACA 4400R series.
Date: March 1939
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department
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Characteristics of Naca 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps

Description: "At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord split flaps, deflected 60 degrees, in the center of the wing and having flat span to wing span ratios of 0.3, 0.5, 0.7, and 1.0, respectively" (p. 1).
Date: January 1941
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of perforated split flaps for use as dive brakes on a rectangular NACA 23012 airfoil

Description: Report presenting an investigation of the aerodynamic characteristics of a rectangular NACA 23012 airfoil with single and double perforated split flaps in the NACA 7- by 10-foot wind tunnel. A large range of flap spans and deflections and a large range of spanwise and chordwise locations of the flaps were investigated. Results regarding the double split flaps, single split flaps, diving speed, and aileron control are provided.
Date: July 1941
Creator: Purser, Paul E.
Partner: UNT Libraries Government Documents Department
open access

Experimental verification of a simplified vee-tail theory and analysis of available data on complete models with vee tails

Description: Report presenting an analysis of available data on vee-tail surfaces. The analysis indicated that a vee tail designed to provide values of stability and control parameters equal to those provided by a conventional tail would probably provide no reduction in area unless the conventional vertical tail is in a bad canopy wake or unless the vee tail has a higher effective aspect ratio than the conventional vertical and horizontal tails.
Date: January 1945
Creator: Purser, Paul E. & Campbell, John P.
Partner: UNT Libraries Government Documents Department
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