# Search Results

## Rolling Moments Due to Rolling and Yaw for Four Wing Models in Rotation

Description: "This report presents the results of a series of autorotation and torque tests on four different rotating wing systems at various rates of roll and at several angles of yaw. The investigation covered an angle of attack range up to 90 degrees and angles of yaw of 0 degree, 5 degrees, 10 degrees, and 20 degrees. The tests were made in a 5-foot, closed-throat atmospheric wind tunnel. The object of the tests was primarily to determine the effects of various angles of yaw on the rolling moments of the rotating wings up to large angles of attack" (p. 301).
Date: August 19, 1930
Creator: Knight, Montgomery & Wenzinger, Carl J.

## A note on secondary flow in rotating radial channels

Description: "A general vector differential equation for the vorticity component parallel to a streamline is derived for steady, nonviscous, and incompressible flow in a rotating system. This equation is then simplified by restricting it to rotating radial channels and by making further simplifying assumptions. The simplified equation is used to solve for the secondary vorticity, the vorticity component parallel to the streamline, in three special cases involving different streamtube geometries; the results are presented in a series of figures" (p. 1).
Date: August 31, 1953
Creator: Kramer, James J. & Stanitz, John D.

## Investigations of Effects of Surface Temperature and Single Roughness Elements on Boundary-Layer Transition

Description: "The laminar boundary layer and the position of the transition point were investigated on a heated flat plate. It was found that the Reynolds number of transition decreased as the temperature of the plate is increased. It is shown from simple qualitative analytical considerations that the effect of variable viscosity in the boundary layer due to the temperature difference produces a velocity profile with an inflection point if the wall temperature is higher than the free-stream temperature" (p. 587).
Date: August 28, 1946
Creator: Liepmann, Hans W. & Fila, Gertrude H.

## Nonlifting Wing-Body Combinations With Certain Geometric Restraints Having Minimum Wave Drag at Low Supersonic Speeds

Description: "Several variational problems involving optimum wing and body combinations having minimum wave drag for different kinds of geometrical restraints are analyzed. Particular attention is paid to the effect on the wave drag of shortening the fuselage and, for slender axially symmetric bodies, the effect of fixing the fuselage diameter at several points or even of fixing whole portions of its shape" (p. 113).
Date: August 4, 1955
Creator: Lomax, Harvard

## Correlation of cylinder-head temperatures and coolant heat rejections of a multicylinder, liquid-cooled engine of 1710-cubic-inch displacement

Description: "Data obtained from an extensive investigation of the cooling characteristics of four multicylinder, liquid-cooled engines have been analyzed and a correlation of both the cylinder-head temperatures and the coolant heat rejections with the primary engine and coolant variables was obtained. The method of correlation was previously developed by the NACA from an analysis of the cooling processes involved in a liquid-cooled-engine cylinder and is based on the theory of nonboiling, forced-convection heat transfer. The data correlated included engine power outputs from 275 to 1860 brake horsepower; coolant flows from 50 to 320 gallons per minute; coolants varying in composition from 100 percent water to 97 percent ethylene glycol and 3 percent water; and ranges of engine speed, manifold pressure, carburetor-air temperature, fuel-air ratio, exhaust-gas pressure, ignition timing, and coolant temperature" (p. 207).
Date: August 31, 1948
Creator: Lundin, Bruce T.; Povolny, John H. & Chelko, Louis J.

## General equations for the stress analysis of rings

Description: In this report it is shown that the shear, axial force, and moment at one point in a simple ring subjected to any loading condition can be given by three independent equations involving certain integrals that must be evaluated regardless of the method of analysis used. It is also shown how symmetry of the ring alone or of the ring and the loading about 1 or 2 axes makes it possible to simplify the three equations and greatly reduces the number of integrals that must be evaluated. Application of the general equations presented in this report to practical problems in the stress analysis of rings makes it possible to shorten, simplify, and systematize the calculations for both simple and braced rings. Three illustrative problems are included to demonstrate the application of the general equations to a simple ring with different loadings.
Date: August 10, 1934
Creator: Lundquist, Eugene E. & Burke, Walter F.

## A Theory for Primary Failure of Straight Centrally Loaded Columns

Description: "A theory of primary failure of straight centrally loaded columns is presented. It is assumed that the column cross section and the load are constant throughout the length. Primary failure is defined as any type of failure in which the cross sections are translated, rotated, or translated and rotated but not distorted in their own planes" (p. 141).
Date: August 17, 1936
Creator: Lundquist, Eugene E. & Fligg, Claude M.

## Comparative drag measurements at transonic speeds of rectangular sweptback NACA 65-009 airfoils mounted on a freely falling body

Description: From Summary: "Directly comparable drag measurements have been made of an airfoil with a conventional rectangular plan form and an airfoil with a sweptback plan form mounted on freely falling bodies. Both airfoils had NACA 65-009 sections and were identical in span, frontal area, and chord perpendicular to the leading edge. The sweptback plan form incorporated a sweepback angle of 45 degrees. The data obtained have been used to establish the relation between the airfoil drag coefficients and the free-stream Mach number over a range of Mach numbers from 0.90 to 1.27. The results of the measurements indicate that the drag of the sweptback plan form is less than 0.3 that of the rectangular plan form at a Mach number of 1.00 and is less than 0.4 that at a Mach number of 1.20."
Date: August 9, 1945
Creator: Mathews, Charles W. & Thompson, Jim Rogers

## Analysis and modification of theory for impact of seaplanes on water

Description: From Summary: "An analysis of available theory on seaplane impact and a proposed modification thereto are presented. In previous methods the overall momentum of the float and virtual mass has been assumed to remain constant during the impact but the present analysis shows that this assumption is rigorously correct only when the resultant velocity of the float is normal to the keel."
Date: August 20, 1945
Creator: Mayo, Wilbur L.

## An experimental study of applied ground loads in landing

Description: Results are presented of an experimental investigation made of the applied ground loads and the coefficient of friction between the tire and the ground during the wheel spin-up process in impacts of a small landing gear under controlled conditions on a concrete landing strip in the Langley impact basin. The basic investigation included three major phases: impacts with forward speed at horizontal velocities up to approximately 86 feet per second, impacts with forward speed and reverse wheel rotation to simulate horizontal velocities up to about 273 feet per second, and spin-up drop tests for comparison with the other tests. In addition to the basic investigation, supplementary tests were made to evaluate the drag-load alleviating effects of prerotating the wheel before impact so as to reduce the relative velocity between the tire and ground.
Date: August 18, 1955
Creator: Milwitzky, Benjamin; Lindquist, Dean C. & Potter, Dexter M.

## Effect of variation of chord and span of ailerons on hinge moments at several angles of pitch

Description: This report presents the results of an investigation of the hinge moments of ailerons of various chords and spans on two airfoils having the Clark Y and USA-27 wing sections, supplementing the investigations described in NACA-TR-298 and NACA-TR-343, of the rolling and yawing moments due to similar ailerons on these two airfoil sections. The measurements were made at various angles of pitch, but at zero angle of roll and yaw, the wing chord being set at an angle of +4 degrees to the fuselage axis.
Date: August 11, 1930
Creator: Monish, B. H.

## Lift Hysteresis at Stall as an Unsteady Boundary-Layer Phenomenon

Description: "Analysis of rotating stall of compressor blade rows requires specification of a dynamic lift curve for the airfoil section at or near stall, presumably including the effect of lift hysteresis. Consideration of the Magnus lift of a rotating cylinder suggests performing an unsteady boundary-layer calculation to find the movement of the separation points of an airfoil fixed in a stream of variable incidence. The consideration of the shedding of vorticity into the wake should yield an estimate of lift increment proportional to time rate of change of angle of attack" (p. 881).
Date: August 17, 1955
Creator: Moore, Franklin K.

## Error in airspeed measurement due to the static-pressure field ahead of an airplane at transonic speeds

Description: The magnitude and variation of the static-pressure error for various distances ahead of sharp-nose bodies and open-nose air inlets and for a distance of 1 chord ahead of the wing tip of a swept wing are defined by a combination of experiment and theory. The mechanism of the error is discussed in some detail to show the contributing factors that make up the error. The information presented provides a useful means for choosing a proper location for measurement of static pressure for most purposes.
Date: August 3, 1955
Creator: O'Bryan, Thomas C.; Danforth, Edward C. B. & Johnston, J. Ford

## Application of the Analogy Between Water Flow With a Free Surface and Two-Dimensional Compressible Gas Flow

Description: "The theory of the hydraulic analogy -- that is, the analogy between water flow with a free surface and two-dimensional compressible gas flow -- and the limitations and conditions of the analogy are discussed. A test was run using the hydraulic analogy as applied to the flow about circular cylinders of various diameters at subsonic velocities extending into the supercritical range. The apparatus and techniques used in this application are described and criticized" (p. 311).
Date: August 21, 1946
Creator: Orlin, W. James; Lindner, Norman J. & Bitterly, Jack G.

## Drop and Flight Tests on NY-2 Landing Gears Including Measurements of Vertical Velocities at Landing

Description: This investigation was conducted to obtain quantitative information on the effectiveness of three landing gears for the NY-2 (consolidated training) airplane. The investigation consisted of static, drop, and flight tests on landing gears of the oleo-rubber-disk and the mercury rubber-chord types, and flight tests only on a landing gear of the conventional split-axle rubber-cord type. The results show that the oleo gear is the most effective of the three landing gears in minimizing impact forces and in dissipating the energy taken.
Date: August 7, 1931
Creator: Peck, W. D. & Beard, A. P.

## A method of analysis of V-G records from transport operations

Description: A method has been developed for interpreting v-g records taken during the course of commercial transport operation. This method involves the utilization of fairly simple statistical procedures to obtain "flight envelopes," which predict that, on the average, in a stated number of flight hours, one value of airspeed will exceed the envelope, and one positive and one negative acceleration increment will exceed the envelope with equal probability of being experienced at any airspeed. Comparison with the actual data obtained from various airplanes and from various airlines indicates that these envelopes predict the occurrences of large values of acceleration and airspeed with a high degree of accuracy.
Date: August 31, 1945
Creator: Peiser, A. M. & Wilkerson, M.

## A Method of Analysis of V-G Records from Transport Operations

Description: A method has been developed for interpreting V-G records taken during the course of commercial transport operation. This method involves the utilization of fairly simple statistical procedures to obtain "flight envelopes," which predict that, on the average, in a stated number of flight hours, one value of airspeed will exceed the envelope, and one positive and one negative acceleration increment will exceed the envelope with equal probability of being experienced at any airspeed. Comparison with the actual data obtained from various airplanes and from various airlines indicates that these envelopes predict the occurrences of large values of acceleration and airspeed with a high degree of accuracy.
Date: August 31, 1945
Creator: Peiser, A. M. & Wilkerson, M.

## Investigation of the drag of various axially symmetric nose shapes of fineness ratio 3 for Mach numbers from 1.24 to 7.4

Description: Experimental drag measurements at zero angle of attack for various theoretical minimum drag nose shapes, hemispherically blunted cones, and other more common profiles of fineness ratios of about 3 are compared with theoretical results for a Mach number and Reynolds number range of 1.24 to 7.4 and 1.0 x 10 to the 6th power to 7.5 x 10 to the 6th power (based on body length), respectively. The results of experimental pressure-distribution measurements are used for the development of an empirical expression for predicting the pressure drag of hemispherically blunted cones.
Date: August 28, 1952
Creator: Perkins, Edward W.; Jorgensen, Leland H. & Sommer, Simon C.

## Some Effects of Compressibility on the Flow Through Fans and Turbines

Description: "The laws of conservation of mass, momentum, and energy are applied to the compressible flow through a two-dimensional cascade of airfoils. A fundamental relation between the ultimate upstream and downstream flow angles, the inlet Mach number, and the pressure ratio across the cascade is derived. Comparison with the corresponding relation for incompressible flow shows large differences. The fundamental relation reveals two ranges of flow angles and inlet Mach numbers, for which no ideal pressure ratio exists" (p. 123).
Date: August 1, 1945
Creator: Perl, W. & Epstein, H. T.

## Correlation of Cooling Data From an Air-Cooled Cylinder and Several Multicylinder Engines

Description: "The theory of engine-cylinder cooling developed in a previous report was further substantiated by data obtained on a cylinder from a Wright R-1820-G engine. Equations are presented for the average head and barrel temperatures of this cylinder as functions of the engine and the cooling conditions. These equations are utilized to calculate the variation in cylinder temperature with altitude for level flight and climb" (p. 59).
Date: August 15, 1939
Creator: Pinkel, Benjamin & Ellerbrock, Herman H., Jr.

## A Thermodynamic Study of the Turbine-Propeller Engine

Description: "Equations and charts are presented for computing the thrust, the power output, the fuel consumption, and other performance parameters of a turbine-propeller engine for any given set of operating conditions and component efficiencies. Included are the effects of the pressure losses in the inlet duct and the combustion chamber, the variation of the physical properties of the gas as it passes through the system, and the change in mass flow of the gas by the addition of fuel" (p. 117).
Date: August 2, 1951
Creator: Pinkel, Benjamin & Karp, Irvin M.

## Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Description: This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.
Date: August 11, 1942
Creator: Pinkel, Benjamin; Turner, L. Richard; Voss, Fred & Humble, Leroy V.

## Mechanism of Start and Development of Aircraft Crash Fires

Description: "Full-scale aircraft crashes were made to investigate the mechanism of the start and development of aircraft crash fires. The results are discussed herein. This investigation revealed the characteristics of the ignition sources, the manner in which the combustibles spread, the mechanism of the union of the combustibles and ignition sources, and the pertinent factors governing the development of a crash fire as observed in this program" (p. 547).
Date: August 1, 1952
Creator: Pinkel, I. Irving; Preston, G. Merritt & Pesman, Gerard J.

## Pressure distribution over the fuselage of a PW-9 pursuit airplane in flight

Description: "This report presents the results obtained from pressure distribution tests on the fuselage of a PW-9 pursuit airplane in a number of conditions of flight. The investigation was made to determine the contribution of the fuselage to the total lift in conditions considered critical for the wing structure, and also to determine whether the fuselage loads acting simultaneously with the maximum tail loads were of such a character as to be of concern with respect to the structural design of other parts of the airplane. The results show that the contribution of the fuselage toward the total lift is small on this airplane" (p. 327).
Date: August 1, 1930
Creator: Rhode, Richard V. & Lundquist, Eugene E.