You limited your search to:

  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Serial/Series Title: NACA Special Report
 Collection: Technical Report Archive and Image Library
An Approximate Method of Calculation of Relative Humidity Required to Prevent Frosting on Inside of Aircraft Pressure Cabin Windows, Special Report

An Approximate Method of Calculation of Relative Humidity Required to Prevent Frosting on Inside of Aircraft Pressure Cabin Windows, Special Report

Date: December 5, 1940
Creator: Jones, Alun R.
Description: This report has been prepare in response to a request for information from an aircraft company. A typical example was selected for the presentation of an approximate method of calculation of the relative humidity required to prevent frosting on the inside of a plastic window in a pressure type cabin on a high speed airplane. The results of the study are reviewed.
Contributing Partner: UNT Libraries Government Documents Department
Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel, Special Report

Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel, Special Report

Date: January 1, 1940
Creator: Becker, John V.
Description: Determinations of boundary-layer transition on the NACA 0012 and 2301 airfoils were made in the 8-foot high-speed wind tunnel over a range of Reynolds Numbers from 1,600,000 to 16,800,000. The results are of particular significance as compared with flight tests and tests in wind tunnels of appreciable turbulence because of the extremely low turbulence in the high-speed tunnel. A comparison of the results obtained on NACA 0012 airfoils of 2-foot and 5-foot chord at the same Reynolds Number permitted an evaluation of the effect of compressibility on transition. The local skin friction along the surface of the NACA 0012 airfoil was measured at a Reynolds Number of 10,000,000. For all the lift coefficient at which tests were made, transition occurred in the region of estimated laminar separation at the low Reynolds Numbers and approach the point of minimum static pressure as a forward limit at the high Reynolds Numbers. The effect of compressibility on transition was slight. None of the usual parameters describing the local conditions in the boundary layer near the transition point served as an index for locating the transition point. As a consequence of the lower turbulence in the 8-foot high-speed tunnel, the transition points occurred consistently ...
Contributing Partner: UNT Libraries Government Documents Department
A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

Date: May 1, 1942
Creator: Pearson, H. A. & Amderspm. R. F.
Description: As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.
Contributing Partner: UNT Libraries Government Documents Department
Characteristics of NACA 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps

Characteristics of NACA 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps

Date: January 1941
Creator: Greenberg, Harry
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 spit flaps, deflected 60 deg span ratios of 0.3, 0.5, 0.7 and 1.0 respectively. In order to get data from which to calculate the characteristics of the flapped wing, the investigation was extended to include tests of the four rectangular airfoils of the NACA 4400R series (4409R, 4412R, 4415R, and 4418R) with full-span 0.2 chord, trailing edge split flaps deflected 60 deg.
Contributing Partner: UNT Libraries Government Documents Department
Comparison of Intercooler Characteristics

Comparison of Intercooler Characteristics

Date: May 1, 1941
Creator: Reuter, J. George & Valerino, Michael F.
Description: A method is presented of comparing the performance, weight, and general dimensional characteristics of inter-coolers. The performance and dimensional characteristics covered in the comparisons are cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width. A method of presenting intercooler data is described in which two types of charts are plotted; (1) A performance chart setting forth all the important characteristics of a given intercooler and (2) a replot of these characteristics for a number of intercoolers intended to assist in making a selection to satisfy a given set of installation conditions. The characteristics of commercial intercoolers obtained from manufacturers' data and of some computed designs are presented on this basis. A standard test procedure and instrumentation are suggested whereby comparable data may be obtained by different testing organizations.
Contributing Partner: UNT Libraries Government Documents Department
Comparison of Three Exit-Area Control Devices on an N.A.C.A. Cowling, Special Report

Comparison of Three Exit-Area Control Devices on an N.A.C.A. Cowling, Special Report

Date: May 1, 1940
Creator: McHugh, James G.
Description: Adjustable cowling flaps, an adjustable-length cowling skirt, and a bottom opening with adjustable flap were tested as means of controlling the rate of cooling-air flow through an air-cooled radial-engine cowling. The devices were tested in the NACA 20-foot tunnel on a model wing-nacelle-propeller combination, through an airspeed range of 20 to 80 miles per hour, and with the propeller blade angle set 23 degrees at 0.75 of the tip radius. The resistance of the engine to air flow through the cowling was simulated by a perforated plate. The results indicated that the adjustable cowling flap and the bottom opening with adjustable flap were about equally effective on the basis of pressure drop obtainable and that both were more effective means of increasing the pressure drop through the cowling than the adjustable-length skirt. At conditions of equal cooling-air flow, the net efficiency obtained with the adjustable cowling flaps and the adjustable-length cowling skirt was about 1% greater than the net efficiency obtained with the bottom opening with adjustable flap.
Contributing Partner: UNT Libraries Government Documents Department
Compressibility Effects in Aeronautical Engineering

Compressibility Effects in Aeronautical Engineering

Date: August 1, 1941
Creator: Stack, John
Description: 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. In the early phases of the development of the airplane, speeds were so low that the effects of compressibility could be justifiably ignored. During the last war and immediately after, however, propellers exhibited losses in efficiency as the tip speeds approached the speed of sound, and the first experiments of an aeronautical nature were therefore conducted with propellers. Results of these experiments indicated serious losses of efficiency, but aeronautical engineers were not seriously concerned at the ...
Contributing Partner: UNT Libraries Government Documents Department
Critical Compressive Stress for Flat Rectangular Plates Supported Along all Edges and Elastically Restrained Against Rotation Along the Unloaded Edges, Special Report 189

Critical Compressive Stress for Flat Rectangular Plates Supported Along all Edges and Elastically Restrained Against Rotation Along the Unloaded Edges, Special Report 189

Date: May 1, 1941
Creator: Lundquist, Eugene E. & Stowell, Eldbridge Z.
Description: 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 flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.
Contributing Partner: UNT Libraries Government Documents Department
Critical Compressive Stress for Outstanding Flanges

Critical Compressive Stress for Outstanding Flanges

Date: April 1, 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Description: 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.
Contributing Partner: UNT Libraries Government Documents Department
Determination of Flight Paths of an SBD-1 Airplane in Simulated Diving Attacks, Special Report

Determination of Flight Paths of an SBD-1 Airplane in Simulated Diving Attacks, Special Report

Date: March 1, 1943
Creator: Johnson, Harold I.
Description: An investigation has been made to determine the motions of and the flight paths describe by a Navy dive-bombing airplane in simulated diving attacks. The data necessary to evaluate these items, with the exception of the atmospheric wind data, were obtained from automatic recording instruments installed entirely within the airplane. The atmospheric wind data were obtained from the ground by the balloon-theodolite method. The results of typical dives at various dive angles are presented in the form of time histories of the motion of the airplane as well as flight paths calculated with respect to still air and with respect to the ground.
Contributing Partner: UNT Libraries Government Documents Department
Drag of Several Gunner's Enclosures at High Speeds, Special Report

Drag of Several Gunner's Enclosures at High Speeds, Special Report

Date: July 1, 1941
Creator: Stack, John & Moberg, Richard J.
Description: The drag of several types of gunner's turrets, windshields, blisters, and other protuberances, including projecting guns, was investigated at speeds from 75 to 440 miles per hour in the NACA 8-foot high-speed wind tunnel. The various gunner's enclosures were represented by 1/10 and 1/7 full-size models on a midwing-fuselage combination representative of bomber types. Most of the usual types of retractable turrets are very poor aerodynamically; they caused wind drag increments, dependent upon the size of the turret relative to the fuselage and upon the speed, up to twice the drag of the fuselage alone. A large streamline blister sufficient to enclose completely one type of rotating cylindrical turret caused a drag increment of approximately one-half that of the turret and at the same time provided space adequate for two gunners rather than for one gunner. A large portion of the drag increments for some types of turret appeared to be due to adverse effects on the fuselage flow caused by the turret rather than by the direct drag of the turret.
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

Date: January 1, 1943
Creator: Allen, H. Julian & Nitzberg, Gerald E.
Description: The development of the laminar boundary layer in a compressible fluid is considered. Formulas are given for determining the boundary-layer thickness and the ratio of the boundary-layer Reynolds number to the body Reynolds number for airfoils and bodies of revolution. It i s shown that the effect of compressibility will profoundly alter the Reynolds number corresponding to the upper limit of the range of the low-drag coefficients . The available data indicate that for low-drag and high critical compressibility speed airfoils and bodies of revolution, this effect is favorable.
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous over Three Supports

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

Date: November 1, 1940
Creator: Lunquist, Eugene E. & Kotanchik, Joseph N.
Description: The test indicate that "an indiscriminate single application of the Southwell method (for analyzing Exp. Observations in problems of elastic stability)--can result in definite and measurable errors" The test also indicate "that the effect of curvature due to bending on the critical load for the compression flange material of a box beam is probably small and can be neglected." We have not found this to be true in our tests. It is believed that the effect of curvature, together with a small amount of fixity at the ribs, tends to force the stiffeners to bow in each bay thus effectively increasing their end fixity and thereby raising their allowable loads.
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Various Wing-Gun Installations on the Aerodynamic Characteristics of an Airplane Model Equipped with an NACA Low-Drag Wing, Special Report

The Effect of Various Wing-Gun Installations on the Aerodynamic Characteristics of an Airplane Model Equipped with an NACA Low-Drag Wing, Special Report

Date: July 1, 1941
Creator: Muse, Thomas C.
Description: An investigation was made in the NACA 19-foot pressure wind tunnel to determine the effect of various win-gun installation on the aerodynamic characteristics of a model with an NACA low-drag wing. Measurements were made of lift and drag over an angle-of-attack range and for several values of dynamic pressure on a four-tenths scale model of a high-speed airplane equipped with the low-drag wing and with various wing-gun installations. Two installations were tested: one in which the blast tube and part of the gun barrel protrude ahead of the wing and another in which the guns is mounted wholly within the wing. Two types of openings for the latter installation were tested. For each installation three simulated guns were mounted in each wing. The results are given in the form of nondimensional coefficients. The installations tested appear to have little effect on the maximum-lift coefficient of the model. However, the drag coefficient shows a definite change. The least adverse effect was obtained with the completely internal mounting and small nose entrance. The results indicate that a properly designed wing-gun installation will have very little adverse effect on the aerodynamic characteristics of the low-drag wing.
Contributing Partner: UNT Libraries Government Documents Department
The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers

The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers

Date: August 1, 1940
Creator: Rodert, Lewis A.
Description: 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.
Contributing Partner: UNT Libraries Government Documents Department
Effects of Direction of Propeller Rotation on the Longitudinal Stability of the 1/10-Scale Model of the North American XB-28 Airplane with Flaps Neutral, Special Report

Effects of Direction of Propeller Rotation on the Longitudinal Stability of the 1/10-Scale Model of the North American XB-28 Airplane with Flaps Neutral, Special Report

Date: June 1, 1942
Creator: Delany, Noel K.
Description: The effects of direction of propeller rotation on factors affecting the longitudinal stability of the XB-28 airplane were measured on a 1/10-scale model in the 7- by 10-foot tunnel of the Ames Aeronautical Laboratory. The main effect observed was that caused by regions of high downwash behind the nacelles (power off as well as power on with flaps neutral). The optimum direction of propeller rotation, both propellers rotating up toward the fuselage, shifted this region off the horizontal tail and thus removed its destabilizing effect. Rotating both propellers downward toward the fuselage moved it inboard on the tail and accentuated the effect, while rotating both propellers right hand had an intermediate result. Comparisons are made of the tail effects as measured by force tests with those predicted from the point-by-point downwash and velocity surveys in the region of the tail. These surveys in turn are compared with the results predicted from available theory.
Contributing Partner: UNT Libraries Government Documents Department
Experimental Determination of Exhaust Gas Thrust, Special Report

Experimental Determination of Exhaust Gas Thrust, Special Report

Date: February 1, 1940
Creator: Pinkel, Benjamin & Voss, Fred
Description: This investigation presents the results of tests made on a radial engine to determine the thrust that can be obtained from the exhaust gas when discharged from separate stacks and when discharged from the collector ring with various discharge nozzles. The engine was provided with a propeller to absorb the power and was mounted on a test stand equipped with scales for measuring the thrust and engine torque. The results indicate that at full open throttle at sea level, for the engine tested, a gain in thrust horsepower of 18 percent using separate stacks, and 9.5 percent using a collector ring and discharge nozzle, can be expected at an air speed of 550 miles per hour.
Contributing Partner: UNT Libraries Government Documents Department
Experimental investigation of a new type of low-drag wing-nacelle combination

Experimental investigation of a new type of low-drag wing-nacelle combination

Date: July 1, 1942
Creator: Allen, H. J. & Frick, C. W., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
A Flight Investigation of Exhaust-Heat De-Icing, Special Report

A Flight Investigation of Exhaust-Heat De-Icing, Special Report

Date: September 1, 1940
Creator: Rodert, Lewis A. & Jones, Alun R.
Description: The National Advisory Committee for Aeronautics has conducted exhaust-heat de-icing tests inflight t o provide data needed in the application of this method of ice prevention. Thc capacity to extract heat from the exhaust gas for de-icing purposes, the quantity of heat required, and other factors were examined. The results indicate that a wing-heating system employing a spanwise exhaust tube within the leading edge of the wing will make available for de-icing purposes between 30 and 35 percent of the exhaust-gas heat. Data are given by which the heat required for ice prevention can be calculated. Sample calculations have been made, on a basis of existing engine power over wing area ratios, to show that sufficient heating can be obtained for ice protection on modern transport airplanes,.
Contributing Partner: UNT Libraries Government Documents Department
Flight Measurements of the Aileron Characteristics of a Grumman F4F-3 Airplane

Flight Measurements of the Aileron Characteristics of a Grumman F4F-3 Airplane

Date: September 1, 1942
Creator: Kleckner, Harold F.
Description: The aileron characteristics of a Grumman F4F-3 airplane were determined in flight by means of NACA recording and indicating instruments. The results show that the ailerons met NACA minimum requirements for satisfactory control throughout a limited speed range. A helix angle of approximately 0.07 radian was produced with flaps down at speeds from 90 to 115 miles per hour indicated airspeed and with flaps up from 115 to 200 miles per hour. With flaps up at 90 miles per hour, the helix angle dropped to 0.055 radian; above 200 miles per hour heavy aileron stick forces seriously restricted maneuverability in roll.
Contributing Partner: UNT Libraries Government Documents Department
Flight Tests of Exhaust Gas Jet Propulsion, Special Report

Flight Tests of Exhaust Gas Jet Propulsion, Special Report

Date: November 1, 1940
Creator: Pnkel, Benjamin & Turner, L. Richard
Description: Flight test s were conducted on the XP-41 airplane, equipped with a Pratt & Whitney R1830-19, 14-cylinder, air-cooled engine, to determine the increase in flight speed obtainable by the use of individual exhaust stacks directed rearwardly to obtain exhaust-gas thrust. Speed increases up to 18 miles per hour at 20,000 feet altitude were obtained using stacks having an exit area of 3.42 square inches for each cylinder. A slight increase in engine power and decrease in cylinder temperature at a given manifold pressure were obtained with the individual stacks as compared with a collector-ring installation. Exhaust-flame visibility was quite low, particularly in the rich range of fuel-air ratios.
Contributing Partner: UNT Libraries Government Documents Department
Full-Scale Tests of 4- and 6-Blade, Single- and Dual-Rotating Propellers, Special Report

Full-Scale Tests of 4- and 6-Blade, Single- and Dual-Rotating Propellers, Special Report

Date: August 1, 1940
Creator: Biermann, David & Hartman, Edwin P.
Description: Test of 10-foot diameter, 4- and 6-blade single- and dual-rotating propellers were conducted in the 20-foot propeller-research tunnel. The propellers were mounted at the front end of a streamline body incorporating spinners to house the hub portions. The effect of a symmetrical wing mounted in the slipstream was investigated. The blade angles investigated ranged from 20 degrees to 65 degrees; the latter setting corresponds to airplane speeds of over 500 miles per hour. The results indicate that dual-rotating propellers were from 0 to 6% more efficient than single-rotating ones; but when operating in the presence of a wing the gain was reduced about one-half. Other advantages of dual-rotating propellers were found to include greater power absorption and greater efficiency at the low V/nD operating range of high pitch propellers.
Contributing Partner: UNT Libraries Government Documents Department
Full-Scale Tests of Several Propellers Equipped with Spinners, Cuffs, Airfoil and Round Shanks, and NACA 16-Series Sections, Special Report

Full-Scale Tests of Several Propellers Equipped with Spinners, Cuffs, Airfoil and Round Shanks, and NACA 16-Series Sections, Special Report

Date: October 1, 1940
Creator: Biermann, David; Hartman, Edwin P. & Pepper, Edward
Description: Wind-tunnel tests of several propeller, cuff, and spinner combinations were conducted in the 20 foot propeller-research tunnel. Three propellers, which ranged in diameter from 8.4 to 11.25 feet, were tested at the front end of a streamline body incorporating spinners of two diameters. The tests covered a blade angle range from 20 deg to 65 deg. The effect of spinner diameter and propeller cuffs on the characteristics of one propeller was determined. Test were also conducted using a propeller which incorporated aerodynamically good shank sections and using one which incorporated the NACA 16 series sections for the outer 20 percent of the blades. Compressibility effects were not measured, owing to the low testing speeds. The results indicated that a conventional propeller was slightly more efficient when tested in conjunction with a 28 inch diameter spinner than with a 23 inch spinner, and that cuffs increased the efficiency as well as the power absorption characteristics. A propeller having good aerodynamic shanks was found to be definitely superior from the efficiency standpoint to a conventional round-shank propeller with or without cuffs; this propeller would probably be considered structurally impracticable, however. The propeller incorporating the NACA 16 series sections at the tims were ...
Contributing Partner: UNT Libraries Government Documents Department
High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane

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

Date: April 1, 1940
Creator: Becker, John V. & Leonard, Lloyd H.
Description: 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. The critical speed at which the shock occurred on the standard cowlings was 20 miles per hour lower in the presence of the fuselage than in the presence of the wing only. The drag of the complete model was reduced 25% at 300 miles per hour by completely retracting the landing gear, fairing the windshield irregularities, and substituting streamline nacelles (with allowance made for the proper amount of cooling-air flow) for the standard nacelle arrangement. The values of the critical Mach number were extended from 0.47 to 0.60 as a result of ...
Contributing Partner: UNT Libraries Government Documents Department
FIRST PREV 1 2 3 NEXT LAST