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Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid

Description: The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.
Date: June 1948
Creator: Kuo, Yung-Huai
Partner: UNT Libraries Government Documents Department

Tables and charts of flow parameters across oblique shocks

Description: Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
Date: August 1948
Creator: Neice, Mary M.
Partner: UNT Libraries Government Documents Department

Two-dimensional subsonic compressible flows past arbitrary bodies by the variational method

Description: Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
Date: March 1951
Creator: Wang, Chi-Teh
Partner: UNT Libraries Government Documents Department

Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Description: Report presenting the experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine. The data were obtained by subjecting the engine to sinusoidal variation of fuel flow and propeller-blade-angle inputs. A comparison of the analytical and experimental results is provided.
Date: September 1950
Creator: Taylor, Burt L., III & Oppenheimer, Frank L.
Partner: UNT Libraries Government Documents Department

An investigation of forward-located fixed spoilers and deflectors as gust alleviators on an unswept-wing model

Description: Report presenting an investigation in the 300 mph 7- by 10-foot tunnel and gust tunnel to determine the static longitudinal aerodynamic characteristics an the gust-alleviation capabilities of forward-located fixed spoilers, deflectors, or a spoiler-deflector combination on a simulated transport airplane model with an unswept wing. Results regarding the static/force test, dynamic/gust-tunnel test, and short-period frequency and damping are provided.
Date: June 1956
Creator: Croom, Delwin R.; Shufflebarger, C. C. & Huffman, Jarrett K.
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

Wing-body interference at supersonic speeds with an application to combinations with rectangular wings

Description: Report presenting the development of an exact theoretical method that permits the determination of the pressure field of a wing-body combination with a circular body and a wing with supersonic leading and trailing edges. Detailed calculations were performed for wing-body combinations composed of rectangular wings mounted at incidence on bodies at zero angle of attack for effective chord-radius ratios of 4 or less.
Date: April 1952
Creator: Nielsen, Jack N. & Pitts, William C.
Partner: UNT Libraries Government Documents Department

Stability and control characteristics at low speed of an airplane model having a 38.7 degree sweptback wing with aspect ratio 4.51, taper ratio 0.54, and conventional tail surfaces

Description: Report presenting a low-speed wind-tunnel investigation of a scale model of an airplane with a 38.7 degree sweptback wing with an aspect ratio of 4.51, a taper ratio of 0.54, and conventional tail surfaces. Results regarding the lift characteristics, longitudinal stability, longitudinal control, directional stability, lateral control, and directional control are provided.
Date: December 1948
Creator: Lockwood, Vernard E. & Watson, James M.
Partner: UNT Libraries Government Documents Department

Exploratory investigation of the effectiveness of biplane wings with large-chord double slotted flaps in redirecting a propeller slipstream downward for vertical take-off

Description: Results are presented from static-force tests on biplane wings with large-chord double slotted flaps which turn the slipstream of a single counter rotating propeller downward for vertical take-off. The investigation provided information on the effect of chord length, flap deflection, propeller position, end plates, fuselage, and ground proximity on the efficiency of the wing system in turning the propeller slipstream.
Date: October 1956
Creator: Kirby, Robert H.
Partner: UNT Libraries Government Documents Department

A Flight Evaluation and Analysis of the Effect of Icing Conditions on the ZPG-2 Airship

Description: A series of test flights was conducted by the U. S. Navy over a 3- year period to evaluate the effects of icing on the operation of the ZPG-2 airship. In supercooled. clouds, ice formed only on the forward edges of small protuberances and wires and presented no serious hazard to operation. Ice accretions of the glaze type which occurred in conditions described as freezing drizzle adversely affected various components to a somewhat greater extent. The results indicated, a need for protection of certain components such as antennas, propellers, and certain parts of the control system. The tests showed that icing of the large surface of the envelope occurred only in freezing rain or drizzle. Because of the infrequent occurrence of these conditions, the potential maximum severity could not be estimated from the test results. The increases in heaviness caused by icing in freezing rain and drizzle were substantial, but well within the operational capabilities of the airship. In order to estimate the potential operational significance of icing in freezing rain, theoretical calculations were used to estimate: (1) the rate of icing as a function of temperature and rainfall intensity, (2) the climatological probability of occurrence of various combinations of these variables, and (3) the significance of the warming influence of the ocean in alleviating freezing-rain conditions. The results of these calculations suggest that, although very heavy icing rates are possible in combinations of low temperature and high rainfall rate, the occurrence of such conditions is very infrequent in coastal areas and virtually impossible 200 or 300 miles offshore.
Date: April 1, 1958
Creator: Lewis, Willilam & Perkins, Porter J., Jr.
Partner: UNT Libraries Government Documents Department

The flexible mounting of an airplane engine

Description: Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.
Date: July 1923
Creator: Kutzbach, K.
Partner: UNT Libraries Government Documents Department

An exploratory investigation of skin friction and transition on three bodies of revolution at a Mach number of 1.61

Description: Report presenting skin-friction measurements for three bodies of revolution of fineness ratio 12.2 with different shapes and pressure distributions: an ogive-cylinder, a cone-cylinder, and a parabolic body. Tests were made at zero angle of attack and over a range of Reynolds numbers based on body length. Results regarding transition and skin friction, surface-temperature surveys, and correlation of pressure-gradient effects are provided.
Date: June 1954
Creator: Hilton, John H., Jr. & Czarnecki, K. R.
Partner: UNT Libraries Government Documents Department

Exploratory investigation of the use of area suction to eliminate air-flow separation in diffusers having large expansion angles

Description: Tests were made at a mean inlet Mach number of 0.2 with area suction applied to conical diffusers with expansion angles of 30 degrees and 50 degrees and exit to inlet area ratios of 2. Air-flow separation was eliminated with suction mass flows of 3 and 4 percent of the inlet mass flows for the 30 degrees and 50 degrees diffusers, respectively.
Date: October 1956
Creator: Holzhauser, Curt A. & Hall, Leo P.
Partner: UNT Libraries Government Documents Department

Flight measurements of the longitudinal stability, stalling, and lift characteristics of an airplane having a 35 degrees sweptback wing without slots and with 40-percent-span slots and a comparison with wind-tunnel data

Description: Report presenting flight measurements at low speeds to determine the static longitudinal stability, stalling, and lift characteristics of an airplane with a wing sweptback 35 degrees at the quarter-chord line. The airplane was tested without slots on the wing and with slots extending from 40 to 80 percent of the semispan of the sweptback-wing panels measured from the inboard end. Results regarding the static longitudinal stability, stalling characteristics, and lift characteristics are provided.
Date: August 1948
Creator: Sjoberg, S. A. & Reeder, J. P.
Partner: UNT Libraries Government Documents Department

Flight measurements of the stability, control, and stalling characteristics of an airplane having a 35 degree sweptback wing without slots and with 80-percent-span slots and a comparison with wind-tunnel data

Description: Report presenting flight measurements to determine the low-speed flying qualities of an airplane with a wing sweptback 35 degrees at the quarter-chord line. The lateral and directional stability and control characteristics of the airplane without slots and with 80-percent-span slots on the wing are provided.
Date: November 1948
Creator: Sjoberg, S. A. & Reeder, J. P.
Partner: UNT Libraries Government Documents Department

Flight measurements of the lateral and directional stability and control characteristics of an airplane having a 35 degree sweptback wing with 40-percent-span slots and a comparison with wind-tunnel data

Description: Report presenting flight tests conducted to determine the lateral and directional stability and control characteristics of an airplane on which the wing panels are swept back 35 degrees. The wings were equipped with slots extending from 40 to 80 percent of the span of the sweptback wing panels measured from the inboard end. Results regarding the steady sideslips, dynamic directional stability, rudder kicks, and aileron rolls are provided.
Date: January 1948
Creator: Sjoberg, S. A. & Reeder, J. P.
Partner: UNT Libraries Government Documents Department

Bearing tests of magnesium-alloy sheet

Description: From Summary: "Bearing tests of AM-3S, AM-52S, and AM-C57S magnesium-alloy sheet in various thicknesses and tempers were made. Bearing yield and ultimate strengths were determined and compared for various edge distances and for various ratios of loading-pin diameter to sheet thickness. Tensile strengths were determined and ratios of average bearing yield and ultimate strength to tensile strength are given."
Date: June 1943
Creator: Sharp, W. H. & Moore, R. L.
Partner: UNT Libraries Government Documents Department

Bearing tests of 14S sheet and plate

Description: From Summary: "Tests were made to determine bearing yield and ultimate strengths of bare and Alclad 15S-W(exp 1) and 14S-T(exp 1) sheet and plate in thicknesses of 0.064 inch, 0.250 inch, and 0.750 inch. From the results of these tests it was concluded that the ratios of bearing to tensile properties from the with-grain direction were essentially the same as proposed in NACA TN Nos. 901, 920, 974, and 981 for other high-strength aluminum-alloy sheet and plate."
Date: August 1948
Creator: Moore, R. L.
Partner: UNT Libraries Government Documents Department

Torsion tests of 24S-T aluminum-alloy noncircular bar and tubing

Description: From Summary: "Tests of 24S-T aluminum alloy have been made to determine the yield and ultimate strengths in torsion of noncircular bar and tubing. An approximate basis for predicting these torsional strength characteristics has been indicated. The results show that the torsional stiffness and maximum shearing stresses within the elastic range may be computed quite closely by means of existing formulas based on mathematical analysis and the membrane analogy."
Date: January 1943
Creator: Moore, R. L. & Paul, D. A.
Partner: UNT Libraries Government Documents Department

Torsion tests of aluminum-alloy stiffened circular cylinders

Description: Second report in a series presenting torsion testing on aluminum-alloy stiffened circular cylinders. The cylinders were similar to those from the first test with the exception of the wall thickness. Results regarding the action before buckling, buckling of curved panels, tension-field action, and ultimate torsional strengths are provided.
Date: November 1952
Creator: Clark, J. W. & Moore, R. L.
Partner: UNT Libraries Government Documents Department

Torsional stability of aluminum alloy seamless tubing

Description: Torsion tests were made on 51ST aluminum-alloy seamless tubes having diameter-to-thickness ratios of from 77 to 139 and length-to-diameter ratios of from 1 to 60. The torsional strengths developed in the tubes which failed elastically (all tubes having lengths greater than 2 to 6 times the diameter) were in most cases within 10 percent of the value indicated by the theories of Donnel, Timoshenko, and Sturm, assuming a condition of simply supported ends.
Date: March 1939
Creator: Moore, R. L. & Paul, D. A.
Partner: UNT Libraries Government Documents Department

Some comparative tests of plain and alclad 24S-T sheet

Description: Report presenting comparative data on the behavior of plain and alclad 24S-T sheet under several types of structural loading. Results indicated that as far as flexural stiffness and resistance to buckling are concerned, the effect of the soft protective coating on alclad shoot is equivalent to a reduction in thickness of about 7 percent. Results regarding the tensile and compressive properties of materials, bending tests on single thicknesses of sheet, column tests on single thicknesses of sheet, bending tests on box beams, and compression tests on stiffened flat-sheet panels are provided.
Date: August 1941
Creator: Moore, R. L.
Partner: UNT Libraries Government Documents Department