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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Special Report
 Collection: Technical Report Archive and Image Library
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 ...
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Notes on Factors Affecting Geometrical Arrangement of Tricycle-Type Landing Gear

Notes on Factors Affecting Geometrical Arrangement of Tricycle-Type Landing Gear

Date: April 1, 1937
Creator: Wenzinger, Carl J. & Kantrowitz, A. R.
Description: The effects of the geometrical arrangement of tricycle landing gears on various characteristics of an airplane equipped with such landing gear is discussed. The characteristics discussed include directional stability, overturning tendencies, steering and ground handling, shimmy, takeoff, and porpoising. The conclusions are summarized in a table.
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Investigation in the 7-By-10 Foot Wind Tunnel of Ducts for Cooling Radiators Within an Airplane Wing, Special Report

Investigation in the 7-By-10 Foot Wind Tunnel of Ducts for Cooling Radiators Within an Airplane Wing, Special Report

Date: July 1, 1938
Creator: Harris, Thomas A. & Recant, Isidore G.
Description: An investigation was made in the NACA 7- by 10-foot wind tunnel of a large-chord wing model with a duct to house a simulated radiator suitable for a liquid-cooled engine. The duct was expanded to reduce the radiator losses, and the installation of the duct and radiator was made entirely within the wing to reduce form and interference drag. The tests were made using a two-dimensional flow set-up with a full-span duct and radiator. Section aerodynamic characteristics of the basic airfoil are given and also curves showing the characteristics of the various duct-radiator combinations. An expression for efficiency, the primary criterion of merit of any duct, and the effect of the several design parameters of the duct-radiator arrangement are discussed. The problem of throttling is considered and a discussion of the power required for cooling is included. It was found that radiators could be mounted in the wing and efficiently pass enough air for cooling with duct outlets located at any point from 0.25c to 0.70c from the wing leading edge on the upper surface. The duct-inlet position was found to be critical and, for maximum efficiency, had to be at the stagnation point of the airfoil and to change ...
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The Transition Phase in the Take-Off of an Airplane, Special Report

The Transition Phase in the Take-Off of an Airplane, Special Report

Date: December 1, 1937
Creator: Wetmore, J. W.
Description: An investigation was undertaken to determine the character and importance of the transition phase between the ground run and steady climb in the takeoff of an airplane and the effects of various factors on this phase and on the airborne part of the takeoff as a whole. The information was obtained from a series of step-by-step integrations, which defined the motion of the airplane during the transition and which were based on data derived from actual takeoff tests of a Verville AT airplane. Both normal and zoom takeoffs under several loading and takeoff speed conditions were considered. The effects of a moderate wind with a corresponding wind gradient and the effect of proximity of the ground were also investigated. The results show that, for normal takeoffs, the best transition was realized at the lowest possible takeoff speed. Moreover, this speed gave the shortest overall takeoff distance for normal takeoffs. Zoom takeoffs required a shorter overall takeoff run than normal takeoffs, particularly with a heavy landing, if the obstacle to be cleared was sufficiently high (greater than 50 feet); no advantage was indicated to the airplane with a light loading if the height to be cleared was less. The error resulting ...
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The Torsional and Bending Deflection of Full-Scale Duralumin Propeller Blades under Normal Operating Conditions, Special Report

The Torsional and Bending Deflection of Full-Scale Duralumin Propeller Blades under Normal Operating Conditions, Special Report

Date: March 1, 1938
Creator: Hartman, Edwin P. & Biermann, David
Description: The torsional deflection of the blades of three full-scale duralumin propellers operating under various loading conditions was measured by a light-beam method. Angular bending deflections were also obtained as an incidental part of the study. The deflection measurements showed that the usual present-day type of propeller blades twisted but a negligible amount under ordinary flight conditions. A maximum deflection of about 1/10th of a degree was found at V/nD of 0.3 and a smaller deflection at higher values of V/nD for the station at 0.70 radius. These deflections are much smaller than would be expected from earlier tests, but the light-beam method is considered to be much more accurate than the direct-reading transit method used in the previous tests.
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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.
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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,.
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Tests in the Variable-Density Tunnel of Seven Tapered Wings Having N.A.C.A. 230 Mean Lines, Special Report

Tests in the Variable-Density Tunnel of Seven Tapered Wings Having N.A.C.A. 230 Mean Lines, Special Report

Date: August 1, 1937
Creator: Anderson, Raymond F.
Description: At the request of the Materiel Division of the Army Air Corps, seven tapered wings having sections based on the N.A,C.A. 230 mean line were tested in the variable-density wind tunnel, The characteristics of the wings are given.
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Correction of Profile-Drag Results from Variable-Density Tunnel and the Effect on the Choice of Wing-Section Thickness

Correction of Profile-Drag Results from Variable-Density Tunnel and the Effect on the Choice of Wing-Section Thickness

Date: March 1, 1938
Creator: Jacobs, Eastman N.
Description: Profile-drag coefficients published from tests in the N.A.C.A. variable-density tunnel (Technical Reports Nos. 460, 537, 586, and 610, references 1 to 4) have tended to appear high as compared with results from the N.A.C.A. full-scale tunnel (Technical Report No. 530, reference 5) and from foreign sources (references 6 to 8). Such discrepancies were considered in Technical Report No. 586, and corrections for turbulence and tip effects were derived that tended to reduce the profile-drag coefficients, particularly for the thicker airfoils. The corrected profile-drag coefficients, designated by the lower-case symbol cdo as contrasted with the older CDO, have been employed in the airfoil reports published since Technical Report No. 460, but even these corrected results continued to appear high, particularly for the thicker sections. The important practical result is that a smaller increase of drag with airfoil thickness is indicated, which may be of primary importance to the airplane designer in choosing the optimum airfoil sections for actual wings. Further investigations of this subject were, of course, undertaken, one of the most important being an investigation of three symmetrical sections N.A.C A. 0009, 0012, and 0018 under conditions of low turbulence in the full-scale tunnel. Preliminary results from this investigation also ...
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Full-Scale Wind-Tunnel Investigation of Wing-Cooling Ducts Effects of Propeller Slipstream, Special Report

Full-Scale Wind-Tunnel Investigation of Wing-Cooling Ducts Effects of Propeller Slipstream, Special Report

Date: March 1, 1939
Creator: Nickle, F. R. & Freeman, Arthur B.
Description: The safety of remotely operated vehicles depends on the correctness of the distributed protocol that facilitates the communication between the vehicle and the operator. A failure in this communication can result in catastrophic loss of the vehicle. To complicate matters, the communication system may be required to satisfy several, possibly conflicting, requirements. The design of protocols is typically an informal process based on successive iterations of a prototype implementation. Yet distributed protocols are notoriously difficult to get correct using such informal techniques. We present a formal specification of the design of a distributed protocol intended for use in a remotely operated vehicle, which is built from the composition of several simpler protocols. We demonstrate proof strategies that allow us to prove properties of each component protocol individually while ensuring that the property is preserved in the composition forming the entire system. Given that designs are likely to evolve as additional requirements emerge, we show how we have automated most of the repetitive proof steps to enable verification of rapidly changing designs.
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