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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
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
open access

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

Determination of the Effect of Horizontal-Tail Flexibility on Longitudinal Control Characteristics

Description: Report presenting an iteration method for determining the longitudinal control characteristics of a flexible horizontal tail. The method permits factors such as the actual spanwise variation of elasticity and the aerodynamic induction effects due to three-dimensional flow to be accounted for to any degree of accuracy needed. An analysis is also included of the effects of horizontal-tail flexibility on the tail effectiveness, the hinge-moment characteristics, and the control-force gradients in a… more
Date: February 1945
Creator: Harmon, S. M.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel tests of a blunt-nose aileron with beveled trailing edge on an NACA 66(215)-216 airfoil with several modifications of aileron nose and adjacent airfoil contour

Description: Report presenting an investigation of ailerons with a beveled trialing edge and a blunt-nose overhang of 35 percent aileron chord on an NACA 66(215)-26 airfoil in two-dimensional flow. Five configurations were tested with various modifications of the aileron nose and adjacent airfoil contour to determine the effect of modifications on lift and aileron hinge-moment characteristics.
Date: February 1945
Creator: Bird, J. D.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of a High-Critical-Speed Fuselage Scoop Including the Effects of Boundary Layer

Description: Report presenting a large air scoop designed for high critical speed, which has been tested in the 8-foot high-speed tunnel on the fuselage of a scale fighter-type airplane. The effects of boundary layer on scoop characteristics were found to be important at all inlet-velocity ratios. Results regarding the boundary-layer surveys, characteristics of original scoop installation, and characteristics of scoop with boundary-layer passage are provided.
Date: February 1945
Creator: Smith, Norman F. & Baals, Donald D.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of Control-Surface Characteristics: [Part] 18 - A Linked Overhang Aerodynamic Balance

Description: Report presenting wind-tunnel testing in two-dimensional flow to investigate the aerodynamic characteristics of a flap balanced by a large overhang linked to deflect more slowly than the flap. Three lengths of blunt-nose overhang were tested linked to a 0.30-airfoil-chord straight-contour flap on an NACA 66-009 airfoil. Results regarding lift, hinge moment, drag, pitching moment, and practical considerations are provided.
Date: February 1944
Creator: Sears, Richard I. & Liddell, Robert B.
Partner: UNT Libraries Government Documents Department
open access

Determination of the Stability and Control Characteristics of a Tailless All-Wing Airplane Model with Sweepback in the Langley Free-Flight Tunnel

Description: Force and flight tests were performance on an all-wing model with windmilling propellers. Tests were conducted with deflected and retracted flaps, with and without auxiliary vertical tail surfaces, and with different centers of gravity and trim coefficients. Results indicate serious reduction of stick-fixed longitudinal stability because of wing-tip stalling at high lift coefficient. Directional stability without vertical tail is undesirably low. Low effective dihedral should be maintained. Ele… more
Date: February 1945
Creator: Campbell, John P. & Seacord, Charles L., Jr.
Partner: UNT Libraries Government Documents Department
open access

An Electron-Diffraction Examination of Cast-Iron Piston Rings From Single-Cylinder Aircraft Engine Tests

Description: Report presenting an electron-diffraction examination of cast-iron piston rings used in a single-cylinder test engine, which showed the presence of a layer of graphite covering the surface. The wear curves from the rings studied had shown variation from high rates to very low rates of wear.
Date: February 1945
Creator: Nowick, A. S. & Brockway, L. O.
Partner: UNT Libraries Government Documents Department
open access

Flight Investigation of Boundary-Layer Control by Suction Slots on an NACA 35-215 Low-Drag Airfoil at High Reynolds Numbers

Description: Report presenting an investigation of the effectiveness of suction slots as a means of extending the laminar boundary layer in flight at high Reynolds numbers on an NACA 35-215 airfoil. The results showed that, with a slot spacing of about 5 percent of the chord, the laminar boundary layer could be maintained to or slightly beyond 45 percent of the chord.
Date: February 1944
Creator: Zalovcik, John A.; Wetmore, J. W. & von Doenhoff, Albert E.
Partner: UNT Libraries Government Documents Department
open access

Occurrence of Iron Oxides on Cast-Iron Engine Surfaces After Operation

Description: Report presenting an examination of the surfaces of used cast-iron piston rings from various single-cylinder aircraft engine tests by electron diffraction. Generally, the oxide patterns were obtained to an appreciable extent from only the top compression ring of the piston-ring assembly; the other rings gave predominately a graphite pattern.
Date: February 1946
Creator: Nowick, A. S. & Brockway, L. O.
Partner: UNT Libraries Government Documents Department
open access

Knock-limited performance of several internal coolants

Description: Report presenting the effect of internal cooling on the knock-limited performance of AN-F-28 fuel in a CFR engine with the following internal coolants: water, methyl alcohol-water mixture, ammonia-methyl alcohol-water mixture, monomethyllamine-water mixture, dimethylamine-water mixture, and trimethylamine-water mixture.
Date: February 1944
Creator: Bellman, Donald R. & Evvard, John C.
Partner: UNT Libraries Government Documents Department
open access

The reduction of nonuseful pressure losses on air-cooled engine cylinders by means of improved finning and baffling

Description: Report presenting an analysis of the pressure drop that is required to cool a typically baffled radial engine, which shows that a total pressure drop of 58 pounds per square foot is necessary at sea level and 112 pounds per square foot is required at an altitude of 40,000 feet.
Date: February 1943
Creator: Wood, George P.
Partner: UNT Libraries Government Documents Department
open access

Determination of the Stability and Control Characteristics of a Straight-Wing, Tailless Fighter-Airplane Model in the Langley Free-Flight Tunnel

Description: Report presenting an investigation to determine the stability and control characteristics of a straight-wing, tailless fighter model with a pusher propeller in the free-flight tunnel. The investigation consisted principally of force and flight tests of a powered dynamic model. Results regarding longitudinal stability, longitudinal control, trim at high angles of attack, lateral stability, and lateral control are provided.
Date: February 1946
Creator: Seacord, Charles L., Jr. & Ankenbruck, Herman O.
Partner: UNT Libraries Government Documents Department
open access

Flight investigation of boundary-layer control by suction slots on an NACA 35-215 low-drag airfoil at high Reynolds numbers

Description: Report presenting an investigation of the effectiveness of suction slots a a means of extending the laminar boundary layer in flight at high Reynolds numbers using an NACA 35-215 airfoil. Tests were made over a range of indicated airspeeds, lift coefficients, and Reynolds numbers. Results regarding boundary-layer control, air-intake distributions, character of the boundary layer, total-intake rate, and profile-drag coefficient are provided.
Date: February 1944
Creator: Zalovcik, John A.; Wetmore, J. W. & von Doenhoff, Albert E.
Partner: UNT Libraries Government Documents Department
open access

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

Description: Report presenting tests conducted with 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
open access

The Determination of Span Load Distribution at High Speeds by Use of High-Speed Wind-Tunnel Section Data

Description: Report presenting a tabular method for determining the span load distribution at high Mach numbers by utilizing high-speed airfoil section data. This method, which is also called the generalized method, is an easily applied process of successive approximations by which a general application of the lifting-line theory may be used to determine the span load distribution for wings composed of sections with arbitrary lift curves. An example is provided to show how the method is used.
Date: February 1944
Creator: Boshar, John
Partner: UNT Libraries Government Documents Department
open access

A summary of drag results from recent Langley full scale tunnel tests of Army and Navy airplanes

Description: Report presenting the results of a drag investigation of twelve military airplanes in order to increase their speed. The main purpose of the report is to point out undesirable aerodynamic features as a guide to airplane designers. Results regarding the power-plant installation, installations in wings, empennages, armament, canopies, and radio antenna are provided.
Date: February 1945
Creator: Lange, Roy H.
Partner: UNT Libraries Government Documents Department
open access

High-speed wind-tunnel tests of the NACA 23012 and 23012-64 airfoils

Description: Report presenting force tests of the NACA 23012 and 23012-64 airfoils of 24-inch chord in the high-speed wind tunnel at a range of Mach numbers. The results show the variation with mach number of lift, drag, and pitching-moment coefficients at a range of angles of attack.
Date: February 1941
Creator: Becker, John V.
Partner: UNT Libraries Government Documents Department
open access

Development of thermal ice-prevention equipment for the B-24D airplane

Description: Report presenting a thermal ice-prevention system for the B-24D airplane. The report includes a description of the design and an outline of the method of design analysis. Results of performance tests of the installation will be presented in a supplementary report.
Date: February 1943
Creator: Jones, Alun R. & Rodert, Lewis A.
Partner: UNT Libraries Government Documents Department
open access

Investigation of Boundary Layer Transition on Concave Walls

Description: Report presenting an investigation of the transition of the boundary layer from the laminar to the turbulent regime on the concave side of a plate with a radius of curvature of 8.5 feet. Results regarding the mean speed distribution, effect of curvature on the position of the transition point, effect of the pressure gradient on transition, and effect of free stream turbulence on transition are provided.
Date: February 1945
Creator: Liepmann, H. W.
Partner: UNT Libraries Government Documents Department
open access

An Analysis of Jet-Propulsion Systems Making Direct Use of the Working Substance of a Thermodynamic Cycle

Description: From Summary: "The results of the analysis showed that the combined efficiency, which is unacceptably low at speeds less than 300 miles per hour, becomes nearly equal to that of conventional power plants of current design at 500 miles per hour. It was also shown that the efficiency will be increased considerably as the physical limitations on cycle temperature and blower speed are raised and as the efficiencies of the system components are improved."
Date: February 1945
Creator: Rubert, Kennedy F.
Partner: UNT Libraries Government Documents Department
open access

NACA Radio Ground-Speed System for Aircraft

Description: Report presenting a method utilizing the Doppler effect on radio signals for determining the speed and distance traveled of an airplane. The method is called the NACA radio ground-speed system and uses the standard radio transmitter already found in most aircraft. Flight tests were made in which the method was used and the results were consisted with calibrated airspeed indications and stop-watch measurements.
Date: February 1943
Creator: Hastings, Charles E.
Partner: UNT Libraries Government Documents Department
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