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Air-Stream Surveys in the Vicinity of the Tail of a 1/8.33-Scale Powered Model of the Republic XF-12 Airplane

Description: The XF-12 airplane was designed by Republic Aviation Corporation to provide the Army Air Forces with a high performance, photo reconnaissance aircraft. A series of air-stream surveys were made n the vicinity of the empennage of a 1/8.33-scale powered model of the XF-12 airplane in the Langley 19-foot pressure tunnel. Surveys of the vortical-tail region were made through a range of yaw angles of plus or minus 20 degrees at a high and low angle of attack. The horizontal-tail surveys were made over a fairly wide range of angles of attack at zero degrees yaw. Several power and flap conditions were investigated. The results are presented in the form a dynamic pressure ratios, sidewash angles, and downwash angles plotted against vertical distance from the fuselage center line. The results of the investigation indicate that a vertical tail located in a conventional position would be in a field of flow where the dynamic pressure ratios at the horizontal tail to be increased; for equal lift coefficients, the effect of power or flap deflection on the direction of flow at any particular point in the region of the horizontal tail is small.
Date: April 8, 1947
Creator: Foster, Gerald V.
Partner: UNT Libraries Government Documents Department

Altitude-Wind-Tunnel Investigation of the 19B-2, 19B-8 and 19XB-1 Jet- Propulsion Engines, 4, Analysis of Compressor Performance

Description: Investigations were conducted in the Cleveland altitude wind tunnel to determine the performance and operational characteristics of the 19B-2, 19B-8, and 19XS-1 turbojet engines. One objective was to determine the effect of altitude, flight Mach number, and tail-pipe-nozzle area on the performance characteristics of the six-stage and ten-stage axial-flow compressors of the 19B-8 and 19XB-1 engines, respectively, The data were obtained over a range of simulated altitudes and flight Mach numbers. At each simulated flight condition the engine was run over its full operable range of speeds. Performance characteristics of the 19B-8 and 19XB-1 compressors for the range of operation obtainable in the turboJet-engine installation are presented. Compressor characteristics are presented as functions of air flow corrected to sea-level conditions, compressor Mach number, and compressor load coefficient. For the range of compressor operation investigated, changes in Reynolds number had no measurable effect on the relations among compressor Mach number, corrected air flow, compressor load coefficient, compressor pressure ratio, and compressor efficiency. The operating lines for the 19B-8 compressor lay on the low-air-flow side of the region of maximum compressor efficiency; the 19B-8 compressor operated at higher average pressure coefficients per stage and produced a lower over-all pressure ratio than did the 19XB-1 compressor.
Date: April 4, 1947
Creator: Dietz, Robert O. & Kuenzig, John K.
Partner: UNT Libraries Government Documents Department

The application of high-temperature strain gauges to the measurements of vibratory stresses in gas-turbine buckets

Description: The feasibility of measuring the vibration in the buckets of a gas turbine under service conditions of speed and temperature was determined by use of a high temperature wire strain gauge cemented to a modified supercharger turbine bucket. A high-temperature wire strain gauge and the auxiliary mechanical and electrical equipment developed for the investigation are described.
Date: April 1, 1947
Creator: Kemp, R H; Morgan, W C & Manson, S S
Partner: UNT Libraries Government Documents Department

The Combination of Internal-Combustion Engine and Gas Turbine

Description: While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given. The critical evaluation of the possibilities of development and fields of application of the various combustion engine systems, wherever it is not clearly expressed in the publications referred to, represents the opinion of the author. The state of development of the internal-combustion engine is in its main features generally known. It is used predominantly at the present time for the propulsion of aircraft and road vehicles and, except for certain restrictions due to war conditions, has been used to an increasing extent in ships and rail cars and in some fields applied as stationary power generators. In the Diesel engine a most economical heat engine with a useful efficiency of about 40 percent exists and in the Otto aircraft engine a heat engine of greatest power per unit weight of about 0.5 kilogram per horsepower.
Date: April 1, 1947
Creator: Zinner, K.
Partner: UNT Libraries Government Documents Department

Cooling of Gas Turbines, IV - Calculated Temperature Distribution in the Trailing Part of a Turbine Blade Using Direct Liquid Cooling

Description: A theoretical analysis of the temperature distribution through the trailing portion of a blade near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the hot spot temperatures at the trailing edge and influence of design variables. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.
Date: April 18, 1947
Creator: Brown, W. Byron & Monroe, William R.
Partner: UNT Libraries Government Documents Department

Correlation of the Trim Limits of Stability Obtained for a PB2Y-3 Flying Boat and a 1/8-Size Powered Dynamic Model

Description: Tests of a PB2Y-3 flying boat were made at the U.S> Naval Air Station, Patuxent River, Md., to determine its hydrodynamic trim limits of stability. Corresponding tests were also made of a 1/8-size powered dynamic model of the same flying boat in Langley tank no. 1. During the tank tests, the full-size testing procedure was reproduced as closely as possible in order to obtain data for a direct correlation of the results. As a nominal gross load of 66,000 pounds, the lower trim limits of the full-size and model were in good agreement above a speed of 80 feet per second. As the speed decreased below 80 feet per second, the difference between the model trim limits and full-scale trim limits gradually became larger. The upper trim limit of the model with flaps deflected 0 deg was higher than that of the full-size, but the difference was small over the speed range compared. At flap deflections greater than 0 deg, it was not possible to trim either the model of the airplane to the upper limit with the center of gravity at 28 percent of the mean aerodynamic chord. The decrease in the lower trim limits with increase in flap deflection showed good agreement for the airplane and model. The lower trim limits obtained at different gross loads for the full-size airplane were reduced to approximately a single curve by plotting trim against the square root of C(sub delta (sub o)) divided by C(sub V).
Date: April 22, 1947
Creator: Garrison, Charlie C. & Hacskaylo, Andrew
Partner: UNT Libraries Government Documents Department

The Distribution of Loads on Rivets Connecting a Plate to a Beam under Transverse Loads

Description: This report gives theoretical discussion of the distribution of leads on rivets connecting a plate to a beam under transverse leads. Two methods of solution are given which are applicable to loads up to the limit of proportionality; in the first the rivets are treated as discrete members, and in the second they are replaced by a continuous system of jointing. A method of solution is also given which is applicable to the case when nonlinear deformations occur in the rivets and the plate, but not in the beam. The methods are illustrated by numerical examples, and these show that the loads carried by the rivets and the plate are less than the values given by classical theory, which does not take into account the slip of the rivets, even below the limit of proportionality. The difference is considerably accentuated when nonlinear deformations occur in the restructure and the beam then carries the greater portion of the bending moment. If the material of the beam has a higher proportional limit and a higher ultimate strength than the material of the plate, there is thus a transfer of load from weaker to stronger material, and this is to the advantage of the structure. The methods given are of simple application and are recommended for use in the design of light-alloy structures when the design lead is likely to be above the proportional limit.
Date: April 1, 1947
Creator: Vogt, F.
Partner: UNT Libraries Government Documents Department