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Flight Instrument for Measurement of Liquid-Water Content in Clouds at Temperatures Above and Below Freezing

Description: A principle formerly used in an instrument for cloud detection was further investigated to provide a simple and rapid means for measuring the liquid-water content of clouds at temperatures above and below freezing. The instrument consists of a small cylindrical element so operated at high surface temperatures that the impingement of cloud droplets creates a significant drop in the surface temperature. ? The instrument is sensitive to a wide range of liquid-water content and was calibrated at one set of fixed conditions against rotating multicylinder measurements. The limited conditions of the calibration Included an air temperature of 20 F, an air velocity of 175 miles per hour, and a surface temperature in clear air of 475 F. The results obtained from experiments conducted with the instrument indicate that the principle can be used for measurements in clouds at temperatures above and below freezing. Calibrations for ranges of airspeed, air temperature, and air density will be necessary to adapt the Instrument for general flight use.
Date: March 5, 1951
Creator: Perkins, Porter J.

NACA Conference on Aircraft Loads, Structures, and Flutter

Description: This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results. The papers in this document are in the same form in which they were presented at the Conference in order to facilitate their prompt distribution. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee?s more complete and formal reports. Accordingly, if information from this document is utilized it is requested that this document not be listed as a reference. Individual reports dealing with most of the information presented at the Conference will subsequently be published by NACA and will therefore be suitable as reference material.
Date: March 5, 1957

Icing Characteristics and Anti-Icing Heat Requirements for Hollow and Ternally Modified Gas-Heated Inlet Guide Vanes

Description: A two-dimensional inlet-guide-vane cascade was investigated to determine the effects of ice formations on the pressure losses across the guide vanes and to evaluate the heated gas flow and temperature required to prevent Icing at various conditions. A gas flow of approximately 0.4 percent of the inlet-air flow was necessary for anti-icing a hollow guide-vane stage at an inlet-gas temperature of 500 F under the following icing conditions: air velocity, 280 miles per hour; water content, 0.9 gram per cubic meter; and Inlet-air static temperature, 00 F. Also presented are the anti-icing gas flows required with modifications of the hollow Internal gas passage, which show heatinput savings greater than 50 percent.
Date: December 5, 1950
Creator: Gray, Vernon H. & Bowden, Dean T.

Analysis of rocket, ramjet, and turbojet engines for supersonic propulsion of long-range missiles. 3: Ramjet engine performance

Description: Report presenting ramjet engine performance data over a range of engine design variables to permit selection and evaluation of a ramjet engine configuration for a long-range supersonic missile. Results include engine thrust, drag, fuel consumption, area ratios, and weight, and are suitable for use in design studies of missiles incorporating either internally or externally mounted ramjet engines.
Date: August 5, 1954
Creator: Weber, Richard J. & Luidens, Roger W.

Comparison of free-flight measurements of the zero-lift drag rise of six airplane configurations and their equivalent bodies of revolution at transonic speeds

Description: From Summary: "Free-flight drag measurements are presented which show the practicability of duplicating the zero-lift drag rise of many airplane configurations by simple bodies of revolution. The results confirm the transonic area rule for straight wings, and for delta and modified-delta wings with and without nacelles. The results showed that the area rule did not apply to one swept-wing configuration and an explanation is advanced to explain why it does not apply."
Date: January 5, 1954
Creator: Hall, James Rudyard

Effects of surface roughness and extreme cooling on boundary-layer transition for 15 degrees cone-cylinder in free flight at Mach numbers to 7.6

Description: Report presenting an investigation of three cone-cylinder bodies to obtain boundary-layer-transition data at very low ratios of wall to local stream temperature. Surface finishes at several levels of roughness height were tested. Results regarding the smooth body and rough bodies are provided.
Date: March 5, 1958
Creator: Rabb, Leonard & Krasnican, Milan J.

Flight determination of the effects of rudder-pedal-force characteristics on the aiming error in azimuth of a conventional fighter airplane

Description: Report presenting flight tests to study the effect on aiming error in azimuth of a change in the rudder-pedal-force characteristics of a conventional fighter airplane equipped with an illuminated fixed gunsight. The effect of the modification on the mean azimuth tracking errors was insignificant, but pilots noted that the modified rudder made it tiring to fly the airplane for any length of time.
Date: July 5, 1950
Creator: Winograd, Lee & Van Dyke, Rudolph D., Jr.

Flight determined buffet boundaries of ten airplanes and comparisons with five buffeting criteria

Description: Report presenting the flight-determined buffet boundaries of ten airplanes. Comparisons are made with five possible buffeting criteria related to airfoil-section characteristics. The primary factors that determine buffeting criteria are critical Mach number, Mach number of sonic flow at the crest, lift-divergence Mach number, lift-peak Mach number, and empirical buffeting criterion are provided.
Date: January 5, 1951
Creator: Gadeberg, Burnett L. & Ziff, Howard L.

Flight tests at supersonic speeds to determine the effect of taper on the zero-lift drag of sweptback low-aspect-ratio wings

Description: Report presenting testing using rocket-powered models to provide an experimental comparison with linearized theoretical calculations for zero-lift drag of sweptback tapered wings with thin, symmetrical, double-wedge airfoil sections. The theory compared favorably with experimental results over most of the test range. Taper was generally found to increase wing drag at low supersonic speeds but reduced drag at higher speeds.
Date: September 5, 1950
Creator: Pittel, Murray

Flight measurements with the Douglas D-558-II (BuAero No. 37974) research airplane: low-speed stalling and lift characteristics

Description: Report presenting the low-speed stalling and lift characteristics of the Douglas D-558-II airplane measured in a series of 1 g stalls in four different airplane configurations. Various combinations of landing gear, flaps, inlet-duct flaps, and slats were tested at a range of altitudes.
Date: September 5, 1950
Creator: Stillwell, W. H.; Wilmerding, J. V. & Champine, R. A.

Measurement of uniform flame movement in carbon monoxide - air mixtures containing either added D2O or H2O

Description: Relative velocities of the flame in a carbon monoxide - air mixture containing either added heavy water or light water were measured in a glass tube. Throughout the range of carbon monoxide - air composition, the flame containing added light water had a faster speed than the flame containing heavy water.
Date: July 5, 1950
Creator: Mcdonald, Glen E

Full-scale investigation of boundary-layer control by suction through leading-edge slots on a wing-fuselage configuration having 47.5 degree leading-edge sweep with and without flaps

Description: Report discussing the effects of suction through slots at the .5 percent chord and 2.5 percent chord stations on the longitudinal aerodynamic characteristics of a 47.5 degree sweptback wing-fuselage configuration with and without flaps. Information about the Reynolds number effects, characteristics of the plain wing, wing with split flaps, extensible leading-edge flaps, the effect of power failure, and the drag coefficients is provided.
Date: April 5, 1950
Creator: Pasamanick, Jerome & Sellers, Thomas B.

Free-flight performance of 16-inch-diameter supersonic ram-jet units 2: five units designed for combustion-chamber-inlet Mach number of 0.16 at free-stream Mach number of 1.60 (units B-1, B-2, B-3, B-4, and B-5)

Description: Free-flight performance of five 16-inch-diameter ram-jet units was determined over range of free-stream Mach numbers of 0.50 to 1.86 and gas total-temperature ratios between 1.0 and 6.1 Time histories of performance data are presented for each unit. Correlations illustrate effect of free-stream Mach number and gas total-temperature ratio on diffuser total-pressure recovery, net-thrust coefficient, and external drag coefficient. One unit had smooth steady burning throughout the entire flight and encountered a maximum free-stream Mach number of 1.86 with a net acceleration of approximately 4.2 g's.
Date: May 5, 1950
Creator: Messing, Wesley E. & Simpkinson, Scott H.

Characteristics of flow over inclined bodies of revolution

Description: From Summary: "Experimental force, moment, and center-of-pressure variations for a large number of bodies of revolution have been compared with the calculated characteristics based on the approximate theory developed in NACA-RM-A9I26. The bodies varied in fineness ratio from 4.5 to 21.1, from blunt unboattailed bodies to airship hulls, and the experimental results are given for widely varying Mach number ranges of angle of attack. It is shown that the lift and drag characteristics are fairly accurately predicted by the theory but that the actual center of pressure is more rearward than the theory indicates."
Date: March 5, 1951
Creator: Allen, H. Julian & Perkins, Edward W.

Effect of air distribution on radial temperature distribution in one-sixth sector of annular turbojet combustor

Description: Report presenting an experimental investigation in a one-sixth sector of an annular turbojet combustor to determine a method of controlling radial exhaust-gas-temperature distribution in a gas-turbine combustion chamber. The adjustment in controlling air was made by ducting the dilution air into the combustion zone in a predetermined manner through hollow radial struts or by modifying the basket-wall open-hole area. Results regarding the temperature distribution, temperature-rise efficiency, total-pressure loss, and altitude operating limits are provided.
Date: April 5, 1950
Creator: Mark, Herman & Zettle, Eugene V.

Altitude investigation of performance of turbine-propeller engine and its components

Description: From Introduction: "Results presented herein show the altitude performance of the turbine-propeller engine and its components and the applicability of the generalization method for predicting engine and component performance at altitudes other than the test altitude. Data from a brief investigation of windmilling and altitude starting characteristics of the engine also presented."
Date: October 5, 1950
Creator: Wallner, Lewis E & Saari, Martin J