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 Collection: National Advisory Committee for Aeronautics Collection
Icing properties of noncyclonic winter stratus clouds

Icing properties of noncyclonic winter stratus clouds

Date: September 1, 1947
Creator: Lewis, W.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Icing Frequencies Experienced During Climb and Descent by Fighter-Interceptor Aircraft

Icing Frequencies Experienced During Climb and Descent by Fighter-Interceptor Aircraft

Date: July 1, 1958
Creator: Perkins, Porter J.
Description: Data and analyses are presented on the relative frequencies of occurrence and severity of icing cloud layers encountered by jet aircraft in the climb and descent phases of flights to high altitudes. Fighter-interceptor aircraft operated by the Air Defense Command (USAF) at bases in the Duluth and Seattle areas collected the data with icing meters installed for a l-year period. The project was part of an extensive program conducted by the NACA to collect Icing cloud data for evaluating the icing problem relevant to routine operations. The average frequency of occurrence of icing was found to be about 5 percent of the number of climbs and descents during 1 year of operations The icing encounters were predominantly in the low and middle cloud layers, decreasing above 15,000 feet to practically none above 25,000 feet. The greatest thickness of ice that would accumulate on any aircraft component (as indicated by the accretion on a small object) was measured with the icing meters. The ice thicknesses on a small sensing probe averaged less than 1/32 inch and did not exceed 1/2 inch. Such accumulations are relatively small when compared with those that can form during horizontal flight in icing clouds. The light ...
Contributing Partner: UNT Libraries Government Documents Department
Meteorological Analysis of Icing Conditions Encountered in Low-Altitude Stratiform Clouds

Meteorological Analysis of Icing Conditions Encountered in Low-Altitude Stratiform Clouds

Date: March 1, 1951
Creator: Kline, D. B. & Walker, J. A.
Description: Liquid-water content, droplet size, and temperature data measured during 22 flights in predominatly stratiform clouds through the 1948-49 and the 1949-50 winters are presented. Several icing encounters were of greater severity than those previously measured over the same geographical area, but were within the limits of similar measurements obtained over different terrain within the United States. An analysis of meteorological conditions existing during the 74 flights conducted for four winters indicated an inverse relation of liquid-water concentration to maximum horizontal extent of icing clouds. Data on the vertical extent of supercooled clouds are also presented. Icing conditions were most likely to occur in the southwest and northwest quadrants of a cyclone area, and least likely to occur in the southeast and northeast quadrants where convergent air flow and lifting over the associated warm frontal surface usually cause precipitation. Additional data indicated that, icing conditions were usually encountered in nonprecipitating clouds existing at subfreezing temperatures and were unlikely over areas where most weather observing stations reported the existence of precipitation. Measurements of liquid-water content obtained during 12 flights near the time and location of radiosonde observations were compared with theoretical values. The average liquid-water content of a cloud layer, as measured ...
Contributing Partner: UNT Libraries Government Documents Department
Analysis of Meteorological Data Obtained During Flight in a Supercooled Stratiform Cloud of High Liquid-Water Content

Analysis of Meteorological Data Obtained During Flight in a Supercooled Stratiform Cloud of High Liquid-Water Content

Date: July 11, 1951
Creator: Perkins, Porter J. & Kline, Dwight B.
Description: Flight icing-rate data obtained in a dense and. abnormally deep supercooled stratiform cloud system indicated the existence of liquid-water contents generally exceeding values in amount and extent previously reported over the midwestern sections of the United States. Additional information obtained during descent through a part of the cloud system indicated liquid-water contents that significantly exceeded theoretical values, especially near the middle of the cloud layer.. The growth of cloud droplets to sizes that resulted in sedimentation from the upper portions of the cloud is considered to be a possible cause of the high water contents near the center of the cloud layer. Flight measurements of the vertical temperature distribution in the cloud layer indicated a rate of change of temperature with altitude exceeding that of the moist adiabatic lapse rate. This excessive rate of change is considered to have contributed to the severity of the condition.
Contributing Partner: UNT Libraries Government Documents Department
Preliminary Survey of Icing Conditions Measured During Routine Transcontinental Airline Operation

Preliminary Survey of Icing Conditions Measured During Routine Transcontinental Airline Operation

Date: December 16, 1952
Creator: Perkins, Porter J.
Description: Icing data collected on routine operations by four DC-4-type aircraft equipped with NACA pressure-type icing-rate meters are presented as preliminary information obtained from a statistical icing data program sponsored by the NACA with the cooperation of many airline companies and the United States Air Force. The program is continuing on a much greater scale to provide large quantities of data from many air routes in the United States and overseas. Areas not covered by established air routes are also being included in the survey. The four aircraft which collected the data presented in this report were operated by United Air Lines over a transcontinental route from January through May, 1951. An analysis of the pressure-type icing-rate meter was satisfactory for collecting statistical data during routine operations. Data obtained on routine flight icing encounters from.these four instrumented aircraft, although insufficient for a conclusive statistical analysis, provide a greater quantity and considerably more realistic information than that obtained from random research flights. A summary of statistical data will be published when the information obtained daring the 1951-52 icing season and that to be obtained during the 1952-53 season can be analyzed and assembled. The 1951-52 data already analyzed indicate that the quantity, ...
Contributing Partner: UNT Libraries Government Documents Department
Observations of icing conditions encountered in flight during 1948

Observations of icing conditions encountered in flight during 1948

Date: June 1, 1949
Creator: Lewis, W. & Hoecker, W. H., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Pressure distribution on wing ribs of the VE-7 and TS airplanes in flight

Pressure distribution on wing ribs of the VE-7 and TS airplanes in flight

Date: October 1, 1927
Creator: Rhode, R V
Description: This paper is the first of a series of notes, each of which presents the complete results of pressure distribution tests made by the National Advisory Committee for Aeronautics, on single-wing ribs of the VE-7 and TS airplanes for a particular condition of flight. The level flight results are presented here in the form of curves and show the comparison between the pressure distribution over a representative thin wing, R.A.F.-15, and a moderately thick wing, U.S.A.-27, throughout the range of angle of attack.
Contributing Partner: UNT Libraries Government Documents Department
Note on the air forces on a wing caused by pitching.

Note on the air forces on a wing caused by pitching.

Date: March 1, 1925
Creator: Munk, Max M
Description: The following contains information on the air forces on a wing produced by it's pitching at a finite rate of angular velocity. The condition of smooth flow at the region of the trailing edge is maintained. The wing then experiences the same lift as if moving with the momentary velocity of the rear edge.
Contributing Partner: UNT Libraries Government Documents Department
Airfoil lift with changing angle of attack

Airfoil lift with changing angle of attack

Date: September 1, 1927
Creator: Reid, Elliott G
Description: Tests have been made in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics to determine the effects of pitching oscillations upon the lift of an airfoil. It has been found that the lift of an airfoil, while pitching, is usually less than that which would exist at the same angle of attack in the stationary condition, although exceptions may occur when the lift is small or if the angle of attack is being rapidly reduced. It is also shown that the behavior of a pitching airfoil may be qualitatively explained on the basis of accepted aerodynamic theory.
Contributing Partner: UNT Libraries Government Documents Department
Mass distribution and performance of free flight models

Mass distribution and performance of free flight models

Date: October 1, 1927
Creator: Scherberg, Max & Rhode, R V
Description: This note deals with the mass distribution and performance of free flight models. An airplane model which is to be used in free flight tests must be balanced dynamically as well as statically, e.g., it must not only have a given weight and the proper center of gravity but also a given ellipsoid of inertia. Equations which relate the motions of an airplane and its model are given. Neglecting scale effect, these equations may be used to predict the performance of an airplane, under the action of gravity alone, from data obtained in making dropping tests of a correctly balanced model.
Contributing Partner: UNT Libraries Government Documents Department
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