Report discussing an experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.
From Introduction: "The data included in this report for Nimonic 80A alloy, for instance, represent experiments carried out to help clarify a production problem of grain-size control in an alloy which has been extensively used. The general procedure of the investigation was to carry out controlled laboratory experiments on samples of bar stock to find conditions of heating and hot-working which resulted in abnormal grain growth."
From Introduction: "Light-airplane accident data, compiled by Crash Injury Research of Cornell University Medical College, indicate that human beings have often withstood declarations in excess of those imposed in airplane crashes involving extensive damage to the airplane structure (ref. 1). This study also correlates the extent of damage to the airplane structure with the injury incurred by the occupants during crash accidents."
From Introduction: "A study of crash-impact survival in light airplanes is reported in references 1 and 2. A similar study for fighter airplanes is reported in reference 3. This report discusses crash-impact survival in transport airplanes."
Note presenting an investigation of the accuracy and range of applicability of the linearized theory, second-order theory, tangent-cone method, conical-shock-expansion theory, and Newtonian theory for predicting pressure distributions on pointed bodies of revolution at zero angle of attack. Three shapes, cone, ogive, and a modified optimum body, are investigated over a wide range of fineness ratios and Mach numbers. The results indicated that for most combinations of fineness ratio and Mach number, one of the approximate methods will give reasonable results.
"The accuracy of the substitute-stringer approach for including the effects of shear lag in the calculation of the transverse modes and frequencies of multistringer box beams is investigated. Box beams, the covers of which consist of normal-stress-carrying stringers on sheets which carry not only shear but also normal stress, are analyzed exactly. Frequencies of beams with various numbers of stringers, obtained by means of this exact analysis, serve to determine the possible accuracy of the frequencies obtained by the substitute-stringer approach" (p. 1).
From Introduction: "This report presents a computational procedure which provides for the rapid and accurate calculation of any streamline in a series of special flows. Detailed information is given on the boundary conditions and equations used for computing the characteristic nets and stream function."
"Auxiliary boundary conditions are derived to assure continuity of wall curvature in applying the method of characteristics to the design of two-dimensional symmetrical supersonic nozzles. An illustrative example is included" (p. 1).
From Introduction: "The surging of a system containing a centrifugal- or axial-flow compressor (e.g., refs. 1 to 4) is an example of self-sustained oscillation. Inlets designed for supersonic jet engines also have been observed to induce oscillations (e.g., refs. 5 to 11) which are usually referred to as "buzz." The origin of buzz in ram-jet engines is the subject of the present report."
From Introduction: "The experiments in high-speed flow showed that an intense, high-frequency acoustic radiation is an essential feature of the problem. Consequently, a study of the acoustic field (involving schlieren observations and frequency and intensity measurements) was undertaken. This report presents the salient features of the study, which was mainly exploratory."
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."
"This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory" (p. 1).
From Introduction: "Early in 1951 the National Advisory Committee for Aeronautics published, as Technical Note 2276 (ref. 1), a report by the Aluminum Research Laboratories of the Aluminum Company of America on the results of static and fatigue tests of high-strength aluminum alloy monobloc specimens and bolted joints. In view of special interest shown by several aircraft companies, certain expansions of the test program were undertaken by the Aluminum Research Laboratories and are reported herein."
Report discussing a flight investigation of rocket-powered models of a tailless triangular-wing airplane configuration was made through the transonic and low supersonic speed range at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. An analysis of the aerodynamic coefficients, stability derivatives, and flying qualities based on the results obtained from the successful flight tests of three models is presented.
Report presenting an investigation of the two-dimensional aerodynamic characteristics of three airfoil sections formed by removing various portions of the original chord from the trailing edge of the NACA 0012 airfoil section. Results regarding lift, drag, and pitching moment and aerodynamic center are provided.
"Pressure-distribution and force tests of a circular cylinder have been made in the Langley 11-inch hypersonic tunnel at a Mach number of 6.88, a Reynolds number of 129,000, and angles of attack up to 90 degrees. The results are compared with the hypersonic approximation of Grimminger, Williams, and Young and a simple modification of the Newtonian flow theory. An evaluation of the crossflow theory is made through comparison of present results with available crossflow Mach number drag coefficients" (p. 1).
From Introduction: "The results of one phase of this investigation, presented in reference 1, have indicated that hull drag can be reduced without causing large changes in aerodynamic stability and hydrodynamic performance by the use of high length-beam ratios. Another phase of the investigation, reference 2, indicated that hulls of the deep-step planning-tail type have much lower air drag than the conventional type of hull and about the same aerodynamic stability; tank tests, reference 3, have indicated that this type of hull also has hydrodynamic performance equal to and in some respects superior to the conventional type of hull. Unpublished tank tests have indicated that the hull models presented in the present paper (with the possible exception of the forebody alone for which data are not available) will have acceptable hydrodynamic performance."
Note presenting an investigation to determine the effects of airspeed and angle of attack on the lift, drag, and pitching moment of a shrouded-propeller model with a shroud length of about two-thirds the propeller diameter over an angle of attack from 0 to 90 degrees. Tests were made of the complete model with the propeller operating and also of the shroud and motor combination with the propeller removed.
Report discussing characteristics are given for the two-blade NACA 10-(3)(062)-045 propeller and for the two-blade NACA 10-(3)(08)-045 propeller over a range of advance ratio from 0.5 to 3.8, through a blade-angle range from 20 degrees to 55 degrees measured at the 0.75 radius. Maximum efficiencies of the order of 91.5 to 92 percent were obtained for the propellers. The propeller with the thinner airfoil sections over the outboard portion of the blades, the NACA 10-(3)(062)-045 propeller, had lower losses at high tip speeds, the difference amounting to about 5 percent at a helical tip Mach number of 1.10.
Report presenting an investigation to study the aerodynamic characteristics of an aspect-ratio-20 wing with thick airfoil sections and employing boundary-layer control by suction. The results include the effects of varying suction flow rate, suction-slot configuration, wing surface condition, flap deflection, and Mach number are provided.
From Summary: "The experimental investigation of damping screens described herein was undertaken primarily to test theories of the effects of damping screens and to obtain information on the performance of screens in oblique flow. The characteristics investigated include the damping of longitudinal and lateral components of turbulence, the effect of screens on scale, the conditions for the production of turbulence and eddies by screens, and the damping of spatial variations of mean speed."
Report presenting the aerodynamic characteristics of the NACA 0012 airfoil section at a range of angles of attack from 0 to 180 degrees. Data were obtained at two different Reynolds numbers depending on whether the airfoil surfaces were smooth or had roughness applied at the leading and trailing edges. After the stall with the rounded edge of the airfoil foremost, a second lift-coefficient peak was obtained at an angle of attack of about 45 degrees.
Report presenting two-dimensional tests of eight 6-percent-thick symmetrical airfoils of the supersonic and subsonic types. Static pressures along the surfaces of each airfoil measured over a range of Mach numbers and angles of attack. Results regarding lift coefficient, drag coefficient, quarter-chord pitching-moment coefficient, and schileren photographs of the pressure distributions are provided.
Report presenting an investigation in the low-turbulence pressure tunnel to determine the aerodynamic characteristics of NACA 64-010 and 0010-1.10 airfoil sections. The investigation covered a range of Mach and Reynolds numbers.
From Summary: "An investigation was made to determine the aerodynamic characteristics in the presence of a wing of three-step planning-tail flying-boat hulls which differed only in the amount of step fairing. The purpose of comparison, tests were also made of a transverse-step hull with an extended afterbody."
From Introduction: "The fundamental integral equation for the pressure distribution on an oscillating thin airfoil moving at subsonic speed has been derived by Possio in reference 1. Collocation procedures have been used by Possio, Frazer, and Skan, and others to obtain lift and moment on an oscillating first plate. An important contribution has been made by Dietze (see reference 2 and 3), who has developed an iterative procedure for numerical solution of Possio's integral equation."
From Introduction: "This paper presents the basic design method and experimental results of calibration of a nozzle which was constructed to conform to the analytically determined ordinates."
From Introduction: "A method for the design of three-dimensional nozzles based on axi-symmetric flow is presented in this paper. The design method presented in this paper is general; however, as an illustrative example of the design of a Mach number 10 nozzle with square test section is included."
From Summary: "The aerodynamic design of propellers from considerations of centrifugal force is presented. By applying a constant minimum value of thickness ratio from root to tip and allowing the distribution of required area to appear in the blade plan form, propellers with good efficiency are realized at high Mach numbers by the method of this paper."
From Summary: "The effects of ice formations on the section lift, drag, and pitching-moment coefficients of an unswept NACA 65A004 airfoil section of 6-foot chord were studied.. The magnitude of the aerodynamic penalties was primarily a function of the shape and size of the ice formation near the leading edge of the airfoil. The exact size and shape of the ice formations were determined photographically and found to be complex functions of the operating and icing conditions."
From Introduction: "This investigation provides general information on the magnitudes and directions of the aerodynamic forces and moments acting on a fighter airplane in fully developed spins. The investigation includes the determination of the effects on the aerodynamic forces and moments of varied rudder setting with and against the spin, of tail modifications, and of deflected flaps and lowered landing gear."
From Introduction: "The present paper employs an approach believed to be novel in slender-body theory and is concerned with developing formulas for the forces and moments as well as the stability derivatives for slender wing-body combinations."
From Introduction: "The present paper employs an approach believed to be novel in slender-body theory and is concerned with developing formulas for the forces and moments as well as the stability derivatives for general slender wing-body combinations."
From Introduction: "In the present paper, the emphasis is placed on calculating the variations of total forces and moments with angles of attack and sideslip for a number of slender plane and cruciform wing-tail combinations and for some airplane-type arrangements of a plane wing and a horizontal and vertical tail."
Report presenting an investigation of the aerodynamic characteristics of a four-blade rigid model propeller in the full-scale tunnel for a range of angles of attack, blade angles, and advance ratio. It included a preliminary explanation of vertical descent and a comparison with theory. Results regarding the static thrust and forward flight are provided.
Report discussing an aerodynamic investigation of a slender pointed parabolic body of revolution was conducted at Mach number of 1.92 with and without the effects of an annular supersonic jet exhausting from the base.
From Summary: "The present report presents the chordwise distributions of pressure measured concurrently with the force and moment data of NACA TN 3007."
From Summary: "This report describes a theoretical and experimental investigation of the aerodynamic mixing by a standing sound wave downstream from a continuous line source of heat."
From Introduction: "The present paper contains a first-order evaluation of a number of aerodynamic derivatives for a rectangular wing of infinite aspect ratio at finite angles of attack, based upon the linear perturbation theory for rotational flow."
From Introduction: "In the present paper, a general method is developed for solving low-aspect-ratio problems involving shed vortex sheets. Both direct and inverse problems are considered. The method is applicable for all planar problems where the velocity boundary conditions can be made homogeneous by differentiation in either the streamwise or the spanwise directions."
From Summary: "A free-swiveling vane-type pickup for measuring air flow direction in both the angle-of-attack and angle-of-sideslip directions is described. Test results are presented which indicate that the pickup is aerodynamically stable and has an accuracy, obtained from a bench calibration, of better than 0.3^o under conditions including acceleration up to 20g in any direction, Mach numbers from 0.5 to 2.8, dynamic pressures up to at least 65 psi. Equations and curves which can be used to obtain flow direction at the center of gravity of a maneuvering model are presented."
From Introduction: "This paper is concerned with the derivation of expressions for the velocity potential and associated forces and moments for oscillating triangular wings in supersonic flow."
From Introduction: "The purpose of this paper is to describe one of the means developed for measuring this quantity on a given airplane type- a trailing arm with wheel. A prototype velocity indicator was tested in the Langley impact basin to determine its accuracy. A description of the operation of this type of vertical-velocity indicator, the results of the impact-basin and flight tests, and general evaluation of the indicator are presented herein."
From Summary: "A comparison of optimum profiles determined by the shock-expansion method of this report with corresponding profiles determined by the linearized-theory method of a previous report shows only small differences in shape at Mach numbers up to infinity even though the linearized theory at high supersonic Mach numbers breaks down completely insofar as the drag of the profile is concerned. Curves are presented which show that for thin airfoils the use of a trailing-edge thickness considerably greater than the theoretical optimum can result in an excessive drag penalty at moderate supersonic Mach numbers, though not at hypersonic Mach numbers."
From Introduction: "The present paper is concerned with certain aspects of the behavior of airfoil sections at high angles of attack with particular emphasis on the needs of the helicopter designer."
"The purpose of the present report is to describe the 10- by 14-inch supersonic wind tunnel and its operational characteristics over the nominal Mach number range from 2.7 to 6.3. Rather complete calibration data on characteristics of flow in the test section are presented and briefly discussed" (p. 2).
From Introduction: "This report, prepared at the NACA Lewis laboratory, presents a theoretical evaluation of the variables which govern pulsation amplitude for the cold-flow engine."
From Introduction: "The servo system considered in this report is in the latter category, due mainly to the fact its amplifier tends to saturate. An investigation of the longitudinal dynamic response of the stabilized airplane was made and the results were reported in reference 1. In this investigation it was found that when restricted to linear methods of analysis the performance of the autopilot-aircraft combination could be predicted for only the small range of operation where the elements of the autopilot operated within their linear range."
From Introduction: "The purpose of this paper is to present an analysis of the mass- and heat-transfer process in terms of a simplified physical picture of the turbulent boundary layer subject to the assumptions previously described."
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