Exact solutions of laminar-boundary-layer equations with constant property values for porous wall with variable temperature (open access)

Exact solutions of laminar-boundary-layer equations with constant property values for porous wall with variable temperature

From Summary: "Exact solution of the laminar-boundary-layer equations for wedge-type flow with constant property values are presented for transpiration-cooled surfaces with variable wall temperatures. The difference between wall and stream temperature is assumed proportional to a power of the distance from the leading edge. Solutions are given for a Prandtl number of 0.7 and ranges of pressure-gradient, cooling-air-flow, and wall-temperature-gradient parameters. Boundary-layer profiles, dimensionless boundary-layer thicknesses, and convective heat-transfer coefficients are given in both tabular and graphical form. Corresponding results for constant wall temperature and for impermeable surfaces are included for comparison purposes."
Date: July 15, 1954
Creator: Donoughe, Patrick L. & Livingood, John N. B.
System: The UNT Digital Library
Cooperative Investigation of Relationship Between Static and Fatigue Properties of Wrought N-155 Alloy at Elevated Temperatures (open access)

Cooperative Investigation of Relationship Between Static and Fatigue Properties of Wrought N-155 Alloy at Elevated Temperatures

Report presents the correlation of extensive data obtained relating properties of wrought N-155 alloy under static, combined static and dynamic, and complete reversed dynamic stress conditions. Time period for fracture ranged from 50 to 500 hours at room temperature, 1,000 degrees, 1,200 degrees, and 1,500 degrees F.
Date: June 15, 1953
Creator: NACA Subcommittee on Power-Plant Materials
System: The UNT Digital Library
Similar Solutions for the Compressible Laminar Boundary Layer with Heat Transfer and Pressure Gradient (open access)

Similar Solutions for the Compressible Laminar Boundary Layer with Heat Transfer and Pressure Gradient

"Stewartson's transformation is applied to the laminar compressible boundary-layer equations and the requirement of similarity is introduced, resulting in a set of ordinary nonlinear differential equations previously quoted by Stewartson, but unsolved. The requirements of the system are Prandtl number of 1.0, linear viscosity-temperature relation across the boundary layer, an isothermal surface, and the particular distributions of free-stream velocity consistent with similar solutions. This system admits axial pressure gradients of arbitrary magnitude, heat flux normal to the surface, and arbitrary Mach numbers" (p. 1).
Date: October 15, 1954
Creator: Cohen, Clarence B. & Reshotko, Eli
System: The UNT Digital Library
On the Kernel function of the integral equation relating lift and downwash distributions of oscillating wings in supersonic flow (open access)

On the Kernel function of the integral equation relating lift and downwash distributions of oscillating wings in supersonic flow

From Summary: "This report treats the Kernel function of the integral equation that relates a known or prescribed downwash distribution to an unknown lift distribution for harmonically oscillating wings in supersonic flow. The treatment is essentially an extension to supersonic flow of the treatment given in NACA report 1234 for subsonic flow. For the supersonic case the Kernel function is derived by use of a suitable form of acoustic doublet potential which employs a cutoff or Heaviside unit function. The Kernel functions are reduced to forms that can be accurately evaluated by considering the functions in two parts: a part in which the singularities are isolated and analytically expressed, and a nonsingular part which can be tabulated."
Date: February 15, 1955
Creator: Watkins, Charles E. & Berman, Julian H.
System: The UNT Digital Library
The Flow of a Compressible Fluid Past a Circular Arc Profile (open access)

The Flow of a Compressible Fluid Past a Circular Arc Profile

"The Ackeret iteration process is utilized to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient. The first two terms of the development correspond to the Prandtl-Glauert approximation and yield the well-known correction to the circulation about the profile" (p. 385).
Date: July 15, 1944
Creator: Kaplan, Carl
System: The UNT Digital Library
Method of Matching Performance of Compressor Systems with that of Aircraft Power Sections (open access)

Method of Matching Performance of Compressor Systems with that of Aircraft Power Sections

"A method is developed of easily determining the performance of a compressor system relative to that of the power section for a given altitude. Because compressors, reciprocating engines, and turbines are essentially flow devices, the performance of each of these power-plant components is presented in terms of similar dimensionless ratios. The pressure and temperature changes resulting from restrictions of the charge-air flow and from heat transfer in the ducts connecting the components of the power plant are also expressed by the same dimensionless ratios and the losses are included in the performance of the compressor" (p. 119).
Date: November 15, 1945
Creator: Bullock, Robert O.; Keetch, Robert C. & Moses, Jason J.
System: The UNT Digital Library
Effects of Small Angles of Sweep and Moderate Amounts of Dihedral on Stalling and Lateral Characteristics of a Wing-Fuselage Combination Equipped With Partial- and Full-Span Double Slotted Flaps (open access)

Effects of Small Angles of Sweep and Moderate Amounts of Dihedral on Stalling and Lateral Characteristics of a Wing-Fuselage Combination Equipped With Partial- and Full-Span Double Slotted Flaps

"Tests of a wing-fuselage combinations incorporating NACA 65-series airfoil sections were conducted in the NACA 19-foot pressure tunnel. The investigation included the tests with flaps neutral and with partial- and full-span double slotted flaps deflected to determine the effects of (1) variations of wing sweep between -4 degrees and 8 degrees on stalling and lateral stability and control characteristics and (2) variations of dihedral between 0 degree and 6.75 degrees on lateral stability characteristics" (p. 467).
Date: April 15, 1944
Creator: Teplitz, Jerome
System: The UNT Digital Library
Application of Theodorsen's theory to propeller design (open access)

Application of Theodorsen's theory to propeller design

A theoretical analysis is presented for obtaining, by use of Theodorsen's propeller theory, the load distribution along a propeller radius to give the optimum propeller efficiency for any design condition. The efficiencies realized by designing for the optimum load distribution are given in graphs, and the optimum efficiency for any design condition may be read directly from the graph without any laborious calculations. Examples are included to illustrate the method of obtaining the optimum load distributions for both single-rotating and dual-rotating propellers.
Date: March 15, 1948
Creator: Crigler, John L.
System: The UNT Digital Library
Analysis of variation of piston temperature with piston dimensions and undercrown cooling (open access)

Analysis of variation of piston temperature with piston dimensions and undercrown cooling

From Summary: "A theoretical analysis is presented that permits estimation of the changes in piston-temperature distribution induced by variations in the crown thickness, the ring-groove-pad thickness, and the undercrown surface heat-transfer coefficient. The analysis consists of the calculation of operating temperatures at various points in the piston body on the basis of the experimentally determined surface heat-transfer coefficients and boundary-region temperatures, as well as arbitrarily selected surface coefficients."
Date: January 15, 1948
Creator: Sanders, J. C. & Schramm, W. B.
System: The UNT Digital Library
Consideration of Dynamic Loads on the Vertical Tail by the Theory of Flat Yawing Maneuvers (open access)

Consideration of Dynamic Loads on the Vertical Tail by the Theory of Flat Yawing Maneuvers

"Dynamic yawing effects on vertical-tail loads are considered by a theory of flat yawing maneuvers. A comparison is shown between computed loads and the loads measured in flight on a fighter airplane. The dynamic effects were investigated on a large flying boat for both an abrupt rudder deflection and sinusoidal rudder deflection" (p. 91).
Date: March 15, 1946
Creator: Boshar, John & Davis, Philip
System: The UNT Digital Library
NACA investigation of fuel performance in piston-type engines (open access)

NACA investigation of fuel performance in piston-type engines

This report is a compilation of many of the pertinent research data acquired by the National Advisory Committee for Aeronautics on fuel performance in piston engines. The original data for this compilation are contained in many separate NACA reports which have in the present report been assembled in logical chapters that summarize the main conclusions of the various investigations. Complete details of each investigation are not included in this summary; however, such details may be found, in the original reports cited at the end of each chapter.
Date: May 15, 1951
Creator: Barnett, Henry C.
System: The UNT Digital Library
Some Features of Artificially Thickened Fully Developed Turbulent Boundary Layers with Zero Pressure Gradient (open access)

Some Features of Artificially Thickened Fully Developed Turbulent Boundary Layers with Zero Pressure Gradient

Report gives an account of an investigation conducted to determine the feasibility of artificially thickening a turbulent boundary layer on a flat plate. A description is given of several methods used to thicken artificially the boundary layer. It is shown that it is possible to do substantial thickening and obtain a fully developed turbulent boundary layer, which is free from any distortions introduced by the thickening process, and, as such, is a suitable medium for fundamental research.
Date: September 15, 1950
Creator: Klebanoff, P. S. & Diehl, Z. W.
System: The UNT Digital Library
Hydrocarbon and nonhydrocarbon derivatives of cyclopropane (open access)

Hydrocarbon and nonhydrocarbon derivatives of cyclopropane

The methods used to prepare and purify 19 hydrocarbon derivatives of cyclopropane are discussed. Of these hydrocarbons, 13 were synthesized for the first time. In addition to the hydrocarbons, six cyclopropylcarbinols, five alkyl cyclopropyl ketones, three cyclopropyl chlorides, and one cyclopropanedicarboxylate were prepared as synthesis intermediates. The melting points, boiling points, refractive indices, densities, and, in some instances, heats of combustion of both the hydrocarbon and nonhydrocarbon derivatives of cyclopropane were determined. These data and the infrared spectrum of each of the 34 cyclopropane compounds are presented in this report. The infrared absorption bands characteristic of the cyclopropyl ring are discussed, and some observations are made on the contribution of the cyclopropyl ring to the molecular refractions of cyclopropane compounds.
Date: August 15, 1952
Creator: Slabey, Vernon A.; Wise, Paul H. & Gibbons, Louis C.
System: The UNT Digital Library
Matrix method of determining the longitudinal-stability coefficients and frequency response of an aircraft from transient flight data (open access)

Matrix method of determining the longitudinal-stability coefficients and frequency response of an aircraft from transient flight data

From Summary: "A matrix method is presented for determining the longitudinal-stability coefficients and frequency response of an aircraft from arbitrary maneuvers. The method is devised so that it can be applied to time-history measurements of combinations of such simple quantities as angle of attack, pitching velocity, load factor, elevator angle, and hinge moment to obtain the over-all coefficients. Although the method has been devised primarily for the evaluation of stability coefficients which are of primary interest in most aircraft loads and stability studies, it can be used also, with a simple additional computation, to determine the frequency-response characteristics. The entire procedure can be applied or extended to other problems which can be expressed by linear differential equations."
Date: December 15, 1950
Creator: Donegan, James J. & Pearson, Henry A.
System: The UNT Digital Library
Formulas for the Supersonic Loading, Lift, and Drag of Flat Swept-Back Wings With Leading Edges Behind the Mach Line (open access)

Formulas for the Supersonic Loading, Lift, and Drag of Flat Swept-Back Wings With Leading Edges Behind the Mach Line

"The method of superposition of linearized conical flows has been applied to the calculation of the aerodynamic properties, in supersonic flight, of thin flat, swept-back wings at an angle of attack. The wings are assumed to have rectilinear plan forms, with tips parallel to the stream, and to taper in the conventional sense. The investigation covers the moderately supersonic speed range where the Mach lines from the leading-edge apex lie ahead of the wing" (p. 1147).
Date: March 15, 1950
Creator: Cohen, Doris
System: The UNT Digital Library
A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition (open access)

A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition

From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer located at various chordwise stations for each position of the roughness. These observations indicated that when the roughness is sufficiently submerged in the boundary layer to provide a substantially linear variation of boundary-layer velocity with distance from the surface up to the top of the roughness, turbulent "spots" begin to appear immediately behind the roughness when the Reynolds number based on the velocity at the top of the roughness height exceeds a value of approximately 600. At Reynolds numbers even slightly below the critical value (value for transition), the sandpaper type of roughness introduced no measurable disturbances into the laminar layer downstream of the roughness. The extent of the roughness area does not appear to have an important effect on the critical value of the roughness Reynolds number."
Date: August 15, 1956
Creator: von Doenhoff, Albert E. & Horton, Elmer A.
System: The UNT Digital Library
A method for simulating the atmospheric entry of long-range ballistic missiles (open access)

A method for simulating the atmospheric entry of long-range ballistic missiles

From Summary: "It is demonstrated with the aid of similitude arguments that a model launched from a hypervelocity gun upstream through a special supersonic nozzle should experience aerodynamic heating and resulting thermal stresses like those encountered by a long-range ballistic missile entering the earth's atmosphere. This demonstration hinges on the requirements that model and missile be geometrically similar and made of the same material, and that they have the same flight speed and Reynolds number (based on conditions just outside the boundary layer) at corresponding points in their trajectories. The hypervelocity gun provides the model with the required initial speed, while the nozzle scales the atmosphere, in terms of density variation, to provide the model with speeds and Reynolds numbers over its entire trajectory."
Date: September 15, 1955
Creator: Eggers, A. J., Jr.
System: The UNT Digital Library
Performance and Boundary-Layer Data From 12 Degree and 23 Degree Conical Diffusers of Area Ratio 2.0 at Mach Numbers Up to Choking and Reynolds Numbers Up to 7.5 X 10(6) (open access)

Performance and Boundary-Layer Data From 12 Degree and 23 Degree Conical Diffusers of Area Ratio 2.0 at Mach Numbers Up to Choking and Reynolds Numbers Up to 7.5 X 10(6)

"For each of two inlet-boundary-layer thicknesses, performance and boundary-layer characteristics have been determined for a 12 degree, 10-inch-inlet-diameter diffuser, a 12 degree, 21-inch-inlet-diameter diffuser, and a 23 degree, 21-inch-inlet-diameter diffuser. The investigation covered an inlet Mach number range from about 0.10 to coking. The corresponding inlet Reynolds number, based on inlet diameter, varied from about 0.5 x 10(6) to 7.5 x 10(6)" (p. 1013).
Date: November 15, 1954
Creator: Little, B. H., Jr. & Wilbur, Stafford W.
System: The UNT Digital Library
An Analysis of the Stability of an Airplane With Free Controls (open access)

An Analysis of the Stability of an Airplane With Free Controls

Report presents the results of an investigation made of the essentials to the stability of an airplane with free control surfaces.
Date: August 15, 1940
Creator: Jones, Robert T. & Cohen, Doris
System: The UNT Digital Library
The unsteady lift of a wing of finite aspect ratio (open access)

The unsteady lift of a wing of finite aspect ratio

"Unsteady-lift functions for wings of finite aspect ratio have been calculated by correcting the aerodynamic inertia and the angle of attack of the infinite wing. The calculations are based on the operational method. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the final lift may be considerably less" (p. 1).
Date: June 15, 1939
Creator: Jones, Robert T.
System: The UNT Digital Library
Correlation of Cooling Data From an Air-Cooled Cylinder and Several Multicylinder Engines (open access)

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

"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.
System: The UNT Digital Library
Effect of fuel-air ratio, inlet temperature, and exhaust pressure on detonation (open access)

Effect of fuel-air ratio, inlet temperature, and exhaust pressure on detonation

From Summary: "An accurate determination of the end-gas condition was attempted by applying a refined method of analysis to experimental results. The results are compared with those obtained in Technical Report no. 655. The experimental technique employed afforded excellent control over the engine variables and unusual cyclic reproducibility. This, in conjunction with the new analysis, made possible the determination of the state of the end-gas at any instant to a fair degree of precision. Results showed that for any given maximum pressure the maximum permissible end-gas temperature increased as the fuel-air ratio was increased. The tendency to detonate was slightly reduced by an increase in residual gas content resulting from an increase in exhaust backpressure with inlet pressure constant."
Date: November 15, 1939
Creator: Taylor, E. S.; Leary, W. A. & Diver, J. R.
System: The UNT Digital Library
A study of air flow in an engine cylinder (open access)

A study of air flow in an engine cylinder

A 4-stroke-cycle test engine was equipped with a glass cylinder and the air movements within it were studied while the engine was being motored. Different types of air flow were produced by using shrouded intake valves in various arrangements and by altering the shape of the intake-air passage in the cylinder head. The air movements were made visible by mixing feathers with the entering air, and high-speed motion pictures were taken of them so that the air currents might be studied in detail and their velocities measured. Motion pictures were also taken of gasoline sprays injected into the cylinder on the intake stroke. The photographs showed that: a wide variety of induced air movements could be created in the cylinder; the movements always persisted throughout the compression stroke; and the only type of movement that persisted until the end of the cycle was rotation about the cylinder axis.
Date: September 15, 1938
Creator: Lee, Dana W.
System: The UNT Digital Library
Transonic Flow Past Cone Cylinders (open access)

Transonic Flow Past Cone Cylinders

"Experimental results are presented for transonic flow post cone-cylinder, axially symmetric bodies. The drag coefficient and surface Mach number are studied as the free-stream Mach number is varied and, wherever possible, the experimental results are compared with theoretical predictions. Interferometric results for several typical flow configurations are shown and an example of shock-free supersonic-to-subsonic compression is experimentally demonstrated" (p. 963).
Date: April 15, 1953
Creator: Solomon, George E.
System: The UNT Digital Library