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in creator/contributor: "Coles, Willard D."  
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Icing Limit and Wet-Surface Temperature Variation for Two Airfoil Shapes Under Simulated High-Speed Flight Conditions

Description: Report presenting a study of the wet-surface temperature and stream conditions that result in ice-free surfaces for bodies in flight through icing clouds and a comparison of these experimental results with calculated results using the analytical method. Two symmetrical airfoil models were used in the investigation and testing occurred for a range of Mach numbers and pressure altitudes. Results regarding chordwise variation of pressure distribution, chordwise variation of recovery factor, result… more
Date: February 1955
Creator: Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Icing Characteristics of Typical Light Airplane Engine Induction Systems

Description: "The icing characteristics of two typical light-airplane engine induction systems were investigated using the carburetors and manifolds of engines in the horsepower ranges from 65 to 85 and 165 to 185. The smaller system consisted of a float-type carburetor with an unheated manifold and the larger system consisted of a single-barrel pressure-type carburetor with an oil-jacketed manifold. Carburetor-air temperature and humidity limits of visible and serious Icing were determined for various engi… more
Date: February 1949
Creator: Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Determination of Thermal Conductivity of Low-Density Ice

Description: "The thermal conductivity of low-density ice has been computed from data obtained in an experimental investigation of the heat transfer and mass transfer by sublimation for an iced surface on a flat plate in a high-velocity tangential air stream. The results are compared with data from several sources on the thermal conductivity of packed snow and solid glaze ice. The results show good agreement with the equations for the thermal conductivity of packed snow as a function of snow density. The ag… more
Date: March 1954
Creator: Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Icing Limit and Wet-Surface Temperature Variation for Two Airfoil Shapes Under Simulated High-Speed Flight Conditions

Description: Note presenting an experimental study of the wet-surface temperature and stream conditions that result in ice-free surfaces for bodies in flight through icing clouds, and the results obtained are compared with values calculated using an analytical method. Two symmetrical airfoil models, one of diamond shape and the other of double-circular-arc contour, were used in the investigation. Results regarding the chordwise variation of pressure distribution, chordwise variation of recovery factor, the … more
Date: February 1955
Creator: Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laboratory Investigation of Ice Formation and Elimination in the Induction System of a Large Twin-Engine Cargo Aircraft

Description: "The icing characteristics, the de-icing rate with hot air, and the effect of impact ice on fuel metering and mixture distribution have been determined in a laboratory investigation of that part of the engine induction system consisting of a three-barrel injection-type carburetor and a supercharger housing with spinner-type fuel injection from an 18-cylinder radial engine used on a large twin-engine cargo airplane. The induction system remained ice-free at carburetor-air temperatures above 36 F… more
Date: September 1947
Creator: Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Full-Scale Investigation of Several Jet-Engine Noise-Reduction Nozzles

Description: A number of nozzles which use the mixing interference of adjacent jets for noise suppression were investigated. Reductions in sound power of nearly 70 percent (5 db) with thrust losses of 1 percent were achieved. A method of calculating the limiting frequency affected by this type of suppression nozzle, that is , multiple-slot nozzles, is presented. Data are shown which indicate that further large reductions in sound power are not likely with mixing-interference nozzles.
Date: April 1957
Creator: Coles, Willard D. & Callaghan, Edmund E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Jet-Engine Noise Reduction by Screens Located Transversely Across the Jet

Description: Note presenting an investigation of screens placed transversely across the jet as a noise-reduction device on a full-scale turbojet engine to determine the effect on the sound field of screen mesh, wire diameter, and screen location. The investigation showed that the screens, when properly placed, lower the noise level in the area downstream of the jet exit and increase it upstream.
Date: May 1955
Creator: Callaghan, Edmund E. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Screen-type noise reduction devices for ground running of turbojet engines

Description: Report presenting testing of the use of screens placed across the jet as a means of suppressing jet noise during ground running, which was somewhat offset by increased noise levels ahead of the engine. Air-jet tests showed negligible reduction in sound generation with additional screens. The large reductions obtained by using screens show that noise generated inside the engine by the turbine or combustion contribute only a minor part of the total noise.
Date: July 1957
Creator: Coles, Willard D. & North, Warren J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Investigation of Sublimation of Ice at Subsonic and Supersonic Speeds and Its Relation to Heat Transfer

Description: "An experimental investigation was conducted in a 3.84- by 10-inch tunnel to determine the mass transfer by sublimation, heat transfer, and skin friction for an iced surface on a flat plate for Mach numbers of 0.4, 0.6, and 0.8 and pressure altitudes to 30,000 feet. Measurements of rates of sublimation were also made for a Mach number of 1.3 at a pressure altitude of 30,000 feet. The results show that the parameters of sublimation and heat transfer were 40 to 50 percent greater for an iced surf… more
Date: March 1954
Creator: Coles, Willard D. & Ruggeri, Robert S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of exhaust-nozzle ejectors on turbojet noise generation

Description: From Summary: "Engine noise levels and jet-velocity profiles have been obtained with several turbojet exhaust-nozzle ejectors. An insignificant reduction in total sound power was realized. At subsonic nozzle pressure ratios, total sound power from exhaust-nozzle ejectors or bypass exit configurations can be calculated from primary-jet parameters only."
Date: October 1955
Creator: North, Warren J. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Far Noise Field of Jets 1: Effect of Nozzle Shape

Description: Note presenting an investigation of the effect of nozzle shape on the noise generation of air jets, which was conducted on convergent, convergent-divergent, and several plug-type nozzles. The nozzle areas were approximately equal to the area of a 3- or 4-inch-diameter circular nozzle. Results regarding total acoustic power, sound spectra, and directional effects are provided.
Date: January 1956
Creator: Callaghan, Edmund E. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Far Noise Field of Jets 2: Comparison of Air Jets and Jet Engines

Description: Report presenting a comparison of the noise generation of air jets and turbojet engines under similar free-flight conditions. Results regarding a comparison of the sound power, afterburner data, spectrum measurements, noise data for engine thrust, and frequency distribution for the two engines are provided.
Date: January 1956
Creator: Coles, Willard D. & Callaghan, Edmund E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Investigation of Effect of Jet Exit Configuration on Thrust and Drag

Description: Memorandum presenting an investigation of the problem of performance losses occurring when airplanes equipped with afterburner and cooling-air ejector installations are flown with the afterburner inoperative. Two sources of the performance losses occurring under some operation conditions were identified: an overexpansion of the propulsive jet and an internal shock system and the excessive pumping action resulting from the off-design.
Date: December 20, 1951
Creator: Callaghan, Edmund E. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Far Noise Field of Air Jets and Jet Engines

Description: "An experimental investigation was conducted to study and compare the acoustic radiation of air jets and jet engines. A number of different nozzle-exit shapes were studied with air jets to determine the effect of exit shape on noise generation. Circular, square, rectangular, and elliptical convergent nozzles and convergent-divergent and plug nozzles were investigated" (p. 1).
Date: 1957
Creator: Callaghan, Edmund E. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Full-Scale Investigation of Several Jet-Engine Noise-Reduction Nozzles

Description: "A number of noise-suppression nozzles were tested on full-scale engines. In general, these nozzles achieved noise reduction by the mixing interference of adjacent jets, that is, by using multiple-slot-nozzles. Several of the nozzles achieved reductions in sound power of approximately 5 decibels (nearly 70 percent) with small thrust losses (approx. 1 percent). The maximum sound-pressure level was reduced by as much as 18 decibels in particular frequency bands" (p. 1249).
Date: January 22, 1957
Creator: Coles, Willard D. & Callaghan, Edmund E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laboratory Investigation of Icing in the Carburetor and Supercharger Inlet Elbow of an Aircraft Engine 3: Heated Air as a Means of De-Icing the Carburetor and Supercharger Inlet Elbow

Description: Report discussing the use of a twin-barrel injection carburetor and a supercharger inlet elbow to establish the relation between wet- and dry-bulb temperatures of the de-icing air and time required to recover from air-flow loss due to icing. The tests were performed at several power conditions, icing conditions, temperatures, and dry and humidified air. De-icing time was found to be a function of the nature of the ice formation and of the wet-bulb temperature of the de-icing air.
Date: December 1945
Creator: Lyons, Richard E. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Icing-Protection Requirements for Reciprocating-Engine Induction Systems

Description: Report presenting an investigation of the icing of aircraft-engine induction systems. Criterions for safe operation and for the design of new induction system are established through the investigation. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations.
Date: 1950
Creator: Coles, Willard D.; Rollin, Vern G. & Mulholland, Donald R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Icing-protection requirements for reciprocating-engine induction system

Description: From Summary: "Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laborato… more
Date: June 20, 1949
Creator: Coles, Willard D.; Rollin, Vern G. & Mulholland, Donald R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Turbojet Engine Noise Reduction With Mixing Nozzle-Ejector Combinations

Description: Note presenting tests of several noise suppressors consisting of combinations of mixing nozzles and ejectors on two full-scale turbojet engines. Maximum sound pressure level reductions of 12 decibels and sound power level reductions of 8 decibels were obtained. Acoustic results, jet mixing, and engine performance are provided.
Date: August 1958
Creator: Coles, Willard D.; Mihaloew, John A. & Callaghan, Edmund E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Near noise field of a jet-engine exhaust 2: cross correlation of sound pressures

Description: Pressure cross correlations were obtained over a range of jet velocities both longitudinally and laterally for the overall sound pressure and for several frequency bands. The region of positive correlation was found to increase with distance downstream of the nozzle exit and was greater for lateral than for longitudinal correlations. In general, little change in the correlation curves was found as a function of jet velocity or frequency band width. Measurements made with a fixed and a movable m… more
Date: September 1956
Creator: Callaghan, Edmund E.; Howes, Walton L. & Coles, Willard D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Near Noise Field of a Jet-Engine Exhaust

Description: From Summary: "Aircraft structures located in the near noise field of a jet engine are subjected to extremely high fluctuating pressures that may cause structural fatigue. Studies of such structures have been limited by lack of knowledge of the loadings involved. The acoustic near field produced by the exhaust of a stationary turbojet engine having a high pressure ratio was measured for a single operating condition without burning. The maximum overall sound pressure without afterburning was fou… more
Date: 1957
Creator: Howes, Walton L.; Callaghan, Edmund E.; Coles, Willard D. & Mull, Harold R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Acoustic, thrust, and drag characteristics of several full-scale noise suppressors for turbojet engines

Description: From Introduction: " Considerable analytical and experimental research has been done to find means of reducing the noise levels of the turbojet transports. Noise levels can be decreased by engine redesign to reduce the jet-exit velocity (ref. 1), proper flight-climb techniques (ref. 2), and the use of noise-suppression exhaust nozzles (refs. 3 to 5). The present report is concerned with the last method."
Date: April 1958
Creator: Ciepluch, Carl C.; North, Warren J.; Coles, Willard D. & Antl, Robert J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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