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  Partner: UNT Libraries Government Documents Department
 Decade: 1950-1959
 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
Icing-protection requirements for reciprocating-engine induction systems

Icing-protection requirements for reciprocating-engine induction systems

Date: January 1, 1950
Creator: Rollin, V. G.; Coles, W. D. & Mulholland, D. R.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

Date: January 1, 1952
Creator: Macks, E Fred & Nemeth, Zolton N
Description: A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.
Contributing Partner: UNT Libraries Government Documents Department
Experimental investigation of free-convection heat transfer in vertical tube at large Grashof numbers

Experimental investigation of free-convection heat transfer in vertical tube at large Grashof numbers

Date: January 1, 1955
Creator: Eckert, E R G & Diaguila, A J
Description: Report presents the results of an investigation conducted to study free-convection heat transfer in a stationary vertical tube closed at the bottom. The walls of the tube were heated, and heated air in the tube was continuously replaced by fresh cool air at the top. The tube was designed to provide a gravitational field with Grashof numbers of a magnitude comparable with those generated by the centrifugal field in rotating-blade coolant passages (10(8) to 10(13)). Local heat-transfer coefficients in the turbulent-flow range and the temperature field within the fluid were obtained.
Contributing Partner: UNT Libraries Government Documents Department
Statistical measurements of contact conditions of 478 transport-airplane landings during routine daytime operations

Statistical measurements of contact conditions of 478 transport-airplane landings during routine daytime operations

Date: January 1, 1955
Creator: Silsby, Norman S
Description: Statistical measurements of contact conditions have been obtained, by means of a special photographic technique, of 478 landings of present-day transport airplanes made during routine daylight operations in clear air at the Washington National Airport. From the measurements, sinking speeds, rolling velocities, bank angles, and horizontal speeds at the instant before contact have been evaluated and a limited statistical analysis of the results has been made and is reported in this report.
Contributing Partner: UNT Libraries Government Documents Department
Charts for estimating tail-rotor contribution to helicopter directional stability and control in low-speed flight

Charts for estimating tail-rotor contribution to helicopter directional stability and control in low-speed flight

Date: January 1, 1955
Creator: Amer, Kenneth B & Gessow, Alfred
Description: Theoretically derived charts and equations are presented by which tail-rotor design studies of directional trim and control response at low forward speed can be conveniently made. The charts can also be used to obtain the main-rotor stability derivatives of thrust with respect to collective pitch and angle of attack at low forward speeds. The use of the charts and equations for tail-rotor design studies is illustrated. Comparisons between theoretical and experimental results are presented. The charts indicate, and flight tests confirm, that the region of vortex roughness which is familiar for the main rotor is also encountered by the tail rotor and that prolonged operation at the corresponding flight conditions would be difficult.
Contributing Partner: UNT Libraries Government Documents Department
Theoretical prediction of pressure distributions on nonlifting airfoils at high subsonic speeds

Theoretical prediction of pressure distributions on nonlifting airfoils at high subsonic speeds

Date: January 1, 1955
Creator: Spreiter, John R & Alksne, Alberta
Description: Theoretical pressure distributions on nonlifting circular-arc airfoils in two-dimensional flows with high subsonic free-stream velocity are found by determining approximate solutions, through an iteration process, of an integral equation for transonic flow proposed by Oswatitsch. The integral equation stems directly from the small-disturbance theory for transonic flow. This method of analysis possesses the advantage of remaining in the physical, rather than the hodograph, variable and can be applied in airfoils having curved surfaces. After discussion of the derivation of the integral equation and qualitative aspects of the solution, results of calculations carried out for circular-arc airfoils in flows with free-stream Mach numbers up to unity are described. These results indicate most of the principal phenomena observed in experimental studies.
Contributing Partner: UNT Libraries Government Documents Department
Analog study of interacting and noninteracting multiple-loop control systems for turbojet engines

Analog study of interacting and noninteracting multiple-loop control systems for turbojet engines

Date: January 1, 1955
Creator: Pack, George J & Phillips, W E , Jr
Description: The results of an analog investigation of several turbojet-engine control configurations is presented in this report. Both proportional and proportional-plus-integral controllers were studied, and compensating terms for engine interaction were added to the control system. Data were obtained on the stability limits and the transient responses of these various configurations. Analytical expressions in terms of the component transfer functions were developed for the configurations studied, and the optimum form for the compensation terms was determined. It was found that the addition of the integral term, while making the system slower and more oscillatory, was desirable in that it made the final values of the system parameters independent of source of disturbance and also eliminated droop in these parameters. Definite improvement in system characteristics resulted from the use of proper compensation terms. At comparable gain points the compensated system was faster and more stable. Complete compensation eliminated engine interaction, permitting each loop to be developed to an optimum point independently.
Contributing Partner: UNT Libraries Government Documents Department
Contributions on the mechanics of boundary-layer transition

Contributions on the mechanics of boundary-layer transition

Date: January 1, 1956
Creator: Schubauer, G B & Klebanoff, P S
Description: The manner in which flow in a boundary layer becomes turbulent was investigated on a flat plate at wind speeds generally below 100 feet per second. Hot-wire techniques were used, and many of the results are derived from oscillograms of velocity fluctuations in the transition region. Following a presentation of the more familiar aspects of transition, there are presented the very revealing facts discovered while studying the characteristics of artificially produced turbulent spots. These are: (1) oscillograms of natural transition are identical to oscillograms of spot passage; (2) transition starts from perturbations in the laminar flow as spots which then grow in accordance with the general concept proposed by Emmons. (3) Turbulence always moves downstream followed by laminar flow; (4) the following flow is in a state of calm for a period during which transition will not occur.
Contributing Partner: UNT Libraries Government Documents Department
Cooperative investigation of relationship between static and fatigue properties of wrought n-155 alloy at elevated temperatures

Cooperative investigation of relationship between static and fatigue properties of wrought n-155 alloy at elevated temperatures

Date: January 1, 1956
Creator: unknown
Description: 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.
Contributing Partner: UNT Libraries Government Documents Department
Theoretical calculations of the pressure, forces, and moments at supersonic speeds due to various lateral motions acting on thin isolated vertical tails

Theoretical calculations of the pressure, forces, and moments at supersonic speeds due to various lateral motions acting on thin isolated vertical tails

Date: January 1, 1956
Creator: Margolis, Kenneth & Bobbitt, Percy J
Description: Velocity potentials, pressure, distributions, and stability derivatives are derived by use of supersonic linearized theory for families of thin isolated vertical tails performing steady rolling, steady yawing, and constant-lateral-acceleration motions. Vertical-tail families (half-delta and rectangular plan forms) are considered for a broad Mach number range. Also considered are the vertical tail with arbitrary sweepback and taper ratio at Mach numbers for which both the leading edge and trailing edge of the tail are supersonic and the triangular vertical tail with a subsonic leading edge and a supersonic trailing edge. Expressions for potentials, pressures, and stability derivatives are tabulated.
Contributing Partner: UNT Libraries Government Documents Department
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