You limited your search to:

  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 ...
Contributing Partner: UNT Libraries Government Documents Department
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.
Contributing Partner: UNT Libraries Government Documents Department
Full-Scale Wind-Tunnel Investigation of Wing Cooling Ducts, Special Report

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

Date: October 1, 1938
Creator: Nickle, F. R. & Freeman, Arthur B.
Description: The systematic investigation of wing cooling ducts at the NACA laboratory has been continued with tests in the full-scale wind tunnel on ducts of finite span. These results extend the previous investigation on section characteristics of ducts to higher Reynolds numbers and indicate the losses due to the duct ends. The data include comparisons between ducts completely within the ring and the conventional underslung ducts. Methods of flow regulation were studied and data were obtained for a wide range of internal duct resistance. The results show satisfactory correlation between the finite span and the previously measured section characteristics obtained with full-span ducts. The effects of the various design parameters on the duct characteristics are discussed. The cooling power required for the internal duct installation is shown to be only a small percentage of the engine power.
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
High-Speed Tests of Radial-Engine Cowlings

High-Speed Tests of Radial-Engine Cowlings

Date: April 1, 1939
Creator: Robinson, Russell G. & Becker, John V.
Description: The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the N.A.C.A. 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination mere used in the tests.
Contributing Partner: UNT Libraries Government Documents Department
Ice Prevention on Aircraft by Means of Impregnated Leather Covers, Special Report

Ice Prevention on Aircraft by Means of Impregnated Leather Covers, Special Report

Date: August 1, 1935
Creator: Clay, William C.
Description: The National Advisory Committee for Aeronautics is testing the effectiveness of a method to prevent the formation of ice on airplanes. The system makes use of a leather cover that is attached to the leading edge of the wing. A small tube, attached to the inner surface of the leather, distributes to the leading edge a solution that permeates throughout the leather and inhibits the formation of ice on the surface. About 25 pounds of the liquid per hour would be sufficient to prevent ice from forming on a wing of 50-foot span. The additional gross weight of the system will not be excessive. The tests are not yet completed but the method is thought to be practicable for the wing and it may also be adaptable to the propeller.
Contributing Partner: UNT Libraries Government Documents Department
Intercooler Design for Aircraft, Special Report

Intercooler Design for Aircraft, Special Report

Date: September 1, 1939
Creator: Brevoort, M. J.; Joyner, U. T. & Leifer, M.
Description: When an airplane is operating at high altitude, it is necessary to use a supercharger to maintain ground pressure at the carburetor inlet. This maintenance and high intake-manifold pressure tends to keep the power output of the engine at ground-level value. The air, being compressed by the supercharger, however, is heated by adiabatic compression and friction to a temperature that seriously affect the performance of the engine. It is thus necessary to use an intercooler to reduce the temperature of the air between the supercharger outlet and the carburetor inlet. The amount of cooling required of the intercooler depend on the efficiency of the supercharger installation. In this investigation, several types of intercoolers were compared and a design procedure that will give the best intercooler for a given set of conditions is indicated. The figure of merit used for the selection of the best design was the total power consumed by the intercooler. This value includes the power required to transport the weight of the intercooler as well as the power used to force the charge air and the cooling air through the intercooler. The cost, size and practicality of construction were not considered, inasmuch as it was thought that ...
Contributing Partner: UNT Libraries Government Documents Department
Interference of Tail Surfaces and Wing and Fuselage from Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel

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

Date: January 1, 1939
Creator: Sherman, Albert
Description: 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. An interference burble, which markedly increases the glide-path angle and the stability in pitch before the actual stall, may be considered a means of obtaining satisfactory stalling characteristics for a complete combination.
Contributing Partner: UNT Libraries Government Documents Department
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 ...
Contributing Partner: UNT Libraries Government Documents Department
Investigation of an Electrically Heated Airplane Windshield for Ice Prevention, Special Report

Investigation of an Electrically Heated Airplane Windshield for Ice Prevention, Special Report

Date: March 1, 1939
Creator: Rodert, Lewis A.
Description: A study was made at the National Advisory Committee for Aeronautics Laboratory of the operation of an electrically heated glass panel, which simulated a segment of an airplane windshield, to determine if ice formations, which usually result in the loss of visibility, could be prevented. Tests were made in the 7- by 3-foot ice tunnel, and in flight, under artificially created ice-forming conditions. Ice was prevented from forming on the windshield model in the tunnel by 1.25 watts of power per square inch with the air temperature at 23 F and a velocity of 80 miles per hour. Using an improved model in flight, ice was prevented by 1.43 watts of power per square inch of protected area and 2 watts per inch concentrated in the rim, with the air temperature at 26 F and a velocity of 120 miles per hour. The removal of a preformed ice cap was effected to a limited extent in the tunnel by the use of 1.89 watts of power per square inch when the temperature and velocity were 25 F and 80 miles per hour, respectively. The results indicate that service tests with an improved design are justified.
Contributing Partner: UNT Libraries Government Documents Department
An Investigation of the Drag of Windshields in the 8-Foot High-Speed Wind Tunnel

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

Date: June 1, 1939
Creator: Robinson, Russell G. & Delano, James B.
Description: 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. Transport types varied from a reproduction of a current type to a completely faired windshield. The results show that the drag of windshields of the same frontal area, on airplanes of small to medium size, may account for 15% of the airplane drag or may be reduced to 1%. Optimum values are given for windshield and tail-fairing lengths; the effect, at various radii is shown. The longitudinal profile of a windshield is shown to be most important and the transverse profile, to be much less important. The effects of retaining strips, of steps for telescoping hoods, and of recessed windows are determined. The results show that the drag of transport-type windshields may account for 21% of the fuselage drag or may be reduced ...
Contributing Partner: UNT Libraries Government Documents Department
An Investigation of the Prevention of Ice on the Airplane Windshield

An Investigation of the Prevention of Ice on the Airplane Windshield

Date: November 1, 1939
Creator: Rodert, Lewis A.
Description: An investigation has been completed on several methods for the prevention and removal of ice on an airplane windshield. Tests were made on the use of electric heating, hot-air heating, and an alcohol-dispensing, rotating wiper blade. The results showed that vision through the airplane windshield could be maintained during severe icing conditions by the use of heat. When put in operation prior to the formation of ice on the windshield, the rotating wiper blade prevented the formation of ice. A combination system that employs the use of heated air and a rotating wiper blade would appear to give protection against the formation of ice on the windshield exterior, prevent frost on the interior, and provide for the removal of rainfall.
Contributing Partner: UNT Libraries Government Documents Department
Large-Scale Boundary-Layer Control Tests on Two Wings in the NACA 20-Foot Wind Tunnel, Special Report

Large-Scale Boundary-Layer Control Tests on Two Wings in the NACA 20-Foot Wind Tunnel, Special Report

Date: April 1, 1935
Creator: Freeman, Hugh B.
Description: Tests were made in the N.A.C.A. 20-foot wind tunnel on: (1) a wing, of 6.5-foot span, 5.5-foot chord, and 30 percent maximum thickness, fitted with large end plates and (2) a 16-foot span 2.67-foot chord wing of 15 percent maximum thickness to determine the increase in lift obtainable by removing the boundary layer and the power required for the blower. The results of the tests on the stub wing appeared more favorable than previous small-scale tests and indicated that: (1) the suction method was considerably superior to the pressure method, (2) single slots were more effective than multiple slots (where the same pressure was applied to all slots), the slot efficiency increased rapidly for increasing slot widths up to 2 percent of the wing chord and remained practically constant for all larger widths tested, (3) suction pressure and power requirements were quite low (a computation for a light airplane showed that a lift coefficient of 3.0 could be obtained with a suction as low as 2.3 times the dynamic pressure and a power expenditure less than 3 percent of the rated engine power), and (4) the volume of air required to be drawn off was quite high (approximately 0.5 cubic ...
Contributing Partner: UNT Libraries Government Documents Department
Mechanical Properties of Flush-Riveted Joints

Mechanical Properties of Flush-Riveted Joints

Date: January 1, 1940
Creator: Bruggeman, Wm. C. & Roop, Frederick C.
Description: The strength of representative types of flush-riveted joints has been determined by testing 865 single-shearing, double-shearing, and tensile specimens representing 7 types of rivet and 18 types of joint. The results, presented in graphic form, show the stress at failure, type of failure, and d/t ratio. In general, 'dimpled' joints were appreciably stronger than countersunk or protruding-head joints, but their strength was greatly influenced by constructional details. The optimum d/t ratios have been determined for the several kinds of joints. Photomacrographs of each type show constructional details and, in several instances, cracks in the sheet.
Contributing Partner: UNT Libraries Government Documents Department
Method of Determining the Weights of the Most Important Simple Girders

Method of Determining the Weights of the Most Important Simple Girders

Date: December 1, 1931
Creator: Cassens, J.
Description: This paper presents a series of tables for the simple and more common types of girders, similar to the tables given in handbooks under the heading "Strength of Materials," for determining the moments, deflections, etc., of simple beams. Instead of the uniform cross section there assumed, the formulas given here apply only to girders of "uniform strength," i.e., it is assumed that a girder is so dimensioned that a given load subjects it to a uniform stress throughout its whole length. This principle is particularly applicable to very strong structures. Girders of uniform strength are the lightest girders conceivable, because any girder, all of whose members are stressed to the limit, can not be surpassed by a lighter girder, if the two girders have the same form. The weight G of a member of length l, cross section F and specific gravity gamma is: G = Flgamma.
Contributing Partner: UNT Libraries Government Documents Department
Model tests of a wing-duct system for auxiliary air supply

Model tests of a wing-duct system for auxiliary air supply

Date: January 1, 1941
Creator: Bierman, D. & Corson, B. W., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
NACA Radio Ground-Speed System for Aircraft, Special Report

NACA Radio Ground-Speed System for Aircraft, Special Report

Date: February 1, 1943
Creator: Hastings, Charles E.
Description: A method that utilizes the Doppler effect on radio signals for determining the speed of an airplane and the distance traveled by the airplane has been developed and found to operate satisfactorily. In this method, called the NACA radio ground-speed system, standard readily available radio equipment is used almost exclusively and extreme frequency stability of the transmitters is not necessary. No complicated equipment need be carried in the airplane, as the standard radio transmitter is usually adequate. Actual flight tests were made in which the method was used and the results were consistent with calibrated air speed indications and stop-watch measurements. Inasmuch as the fundamental accuracy of the radio method is far better than either of the checking systems used, no check was made on the limitations of the accuracy.
Contributing Partner: UNT Libraries Government Documents Department
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.
Contributing Partner: UNT Libraries Government Documents Department
Notes on New French Commercial Airplanes

Notes on New French Commercial Airplanes

Date: April 4, 1935
Creator: unknown
Description: This document discusses the types of commercial planes ordered by Air France. Characteristics of the Wibault 670, the Dewoitine D.620, Bloch 300, and the Potez 620 airplanes are included. Pictures and diagrams of these aircraft are also included.
Contributing Partner: UNT Libraries Government Documents Department
Paris Aviation Salon, 1934

Paris Aviation Salon, 1934

Date: November 29, 1934
Creator: unknown
Description: This document reviews the Air show held in Paris in 1934. It includes charts and pictures of the aircraft which were from all parts of Europe.
Contributing Partner: UNT Libraries Government Documents Department
Performance Characteristics of an Aircraft Engine with Exhaust Turbine Supercharger, Special Report

Performance Characteristics of an Aircraft Engine with Exhaust Turbine Supercharger, Special Report

Date: May 1, 1941
Creator: Lester, E. M. & Paulson, V. A.
Description: The Pratt and Whitney Aircraft company and the Naval Aircraft Factory of the United States Navy cooperated in a laboratory and flight program of tests on an exhaust turbine supercharger. Two series of dynamometer tests of the engine super-charger combination were completed under simulated altitude conditions. One series of hot gas-chamber tests was conducted by the manufacturer of the supercharger. Flight demonstrations of the supercharger installed in a twin-engine flying boat were terminated by failure of the turbine wheels. The analysis of the results indicated that a two-stage supercharger with the first-stage exhaust turbine driven will deliver rated power for a given indicated power to a higher altitude, will operate more efficiently, and will require simpler controls than a similar engine with the first stage of the supercharger driven from the crankshaft through multispeed gears.
Contributing Partner: UNT Libraries Government Documents Department
Preliminary Full-Scale Wind-Tunnel Investigation of Wing Ducts for Radiators, Special Report

Preliminary Full-Scale Wind-Tunnel Investigation of Wing Ducts for Radiators, Special Report

Date: March 1, 1938
Creator: Silverstein, Abe & Nickle, F. R.
Description: Wing ducts for liquid-cooled engine radiators have been investigated in the N.A.C.A. full-scale wind tunnel on a large model airplane. The tests were made to determine the relative merits of several types of duct and radiator installations for an airplane of a particular design. In the test program the principal duct dimensions were systematically varied, and the results are therefore somewhat applicable to the general problems of wing duct design, although they should be considered as preliminary and only indicative of the inherent possibilities.
Contributing Partner: UNT Libraries Government Documents Department
Preliminary Investigation of Certain Laminar-Flow Airfoils for Application at High Speeds and Reynolds Numbers

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

Date: August 1, 1939
Creator: Jacobs, E.N.; Abbott, Ira H. & von Doenhoff, A.E.
Description: 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. Drag measurements by the wake-survey method and pressure-distribution measurements were made at several lift coefficients through a range of Reynolds numbers up to 11,400,000. The drag scale-effect curve for the NACA 1412-34 is extrapolated to a Reynolds number of 30,000,000 on the basis of theoretical calculations of the skin friction. Comparable skin-friction calculations were made for the NACA 23012. The results indicate that, for certain applications at moderate values of the Reynolds number, the NACA 1412-34 and 2412-34 airfoils offer some advantages over such conventional airfoils as the ...
Contributing Partner: UNT Libraries Government Documents Department
Preliminary Investigation of the Effect of Compressibility on the Maximum Lift Coefficient, Special Report

Preliminary Investigation of the Effect of Compressibility on the Maximum Lift Coefficient, Special Report

Date: February 1, 1943
Creator: Stack, John; Fedziuk, Henry A. & Cleary, Harold E.
Description: Preliminary data are presented on the variation of the maximum lift coefficient with Mach number. The data were obtained from tests in the 8-foot high-speed tunnel of three NACA 16-series airfoils of 1-foot chord. Measurements consisted primarily of pressure-distribution measurements in order to illustrate the nature of the phenomena. It was found that the maximum lift coefficient of airfoils is markedly affected by compressibility even at Mach numbers as low as 0.2. At high Mach numbers pronounced decrease of the maximum lift coefficient was found. The magnitude of the effects of compressibility on the maximum lift coefficient and the low speeds at which these effects first appear indicate clearly that consideration of the take-off thrust for propellers will give results seriously in error if these considerations are based on the usual low-speed maximum-lift-coefficient data generally used.
Contributing Partner: UNT Libraries Government Documents Department