Memorandum presenting a study of an acceleration-limiting control on a turbojet engine in order to determine its feasibility as an acceleration control. A proportional-plus-integral type of controller was used in the investigation. Results regarding the one-loop control and two-loop control are provided.

Memorandum presenting an acceleration-limiting control used on a turbojet engine to study the feasibility of its use as an acceleration control. A proportional-plus-integral type of controller was used in this investigation. Results regarding one-loop control and two-loop control are provided.

The adhesive and protective characteristics of National Bureau of Standards Coating A-417 were investigated, as well as the effect of the coating on the life of forged Refractaloy 26 and cast Stellite 21 turbine blades. Coated and uncoated blades were run in a full-scale J33-9 engine and were subjected to simulated service operations consisting of consecutive 20-minute cycles (15 min at rated speed and approximately 5 min at idle). The ceramic coating adhered well to Refractaloy 26 and Stellite 21 turbine blades operated at 1500 degrees F. The coating also prevented corrosion of the Refractaloy 26, a corrosion-sensitive nickel-base alloy, and of the Stellite 21, a relatively corrosion-resistant cobalt-base alloy. Although the coating prevented corrosion of both alloys, it had no apparent effect on blade life.

Report presenting an investigation at subsonic and transonic speeds in the high-speed 7- by 10-foot tunnel to determine the aerodynamic characteristics of a 42.7 degree sweptback wing with a 20-percent-chord and 50-percent-span outboard aileron. The investigation was performed in transonic flow over a bump on the tunnel floor and in subsonic flow on one of the tunnel side walls.

Report presenting wind-tunnel tests made to determine the aerodynamic characteristics of a scale model of a high-speed bomber with a dual pusher propeller aft of the empennage. Some of the results discussed include longitudinal, lateral, and directional stability and control, the empennage design, and ground effects on the aerodynamic characteristics. The results indicate that this particular airplane has several advantages with regard to stability and control over the conventional-type single-engine airplane configuration.

Report presenting an investigation to determine the aerodynamic characteristics of a cruciform 70 degree delta-wing missile configuration with 70 degree delta canard control surfaces at M = 1.41 in the 4- by 4-foot supersonic pressure tunnel. Modifications to the configuration included variation of the body length and canard area and the substitution of a series of very small span wings for the cruciform delta wings and canard controls.

Report presenting an analysis of the force distribution on a slender pointed body of revolution at angle of attack utilizing pressure-distribution data and balance measurements. The data were obtained in the supersonic tunnel at a variety of Mach numbers and angles of attack. Results regarding normal forces and axial force are provided.

Report presenting an investigation at two Mach numbers to examine the flow, force, and moment characteristics associated with spoilers mounted on a flat plate at a range of sweep angles. Pressure measurements were obtained over the plate and spoiler faces. The pressures were integrated to determine the spoiler lift, pitching-moment, drag, and hinge-moment characteristics.

From Introduction: "The data obtained for each configuration are presented in a manner to show the effects of fuel distribution and flame-holder design on net thrust, specific fuel consumption, exhaust-gas temperature, combustion efficiency, operable range of tail-pipe-burner fuel-air ratios, and maximum altitude limit."

From Introduction: "The investigation reported herein, which was conducted in an NACA Lewis altitude test chamber, covered a range of altitudes from 30,000 to 50,000 feet at a flight Mach number of 0.8."

From Introduction: "Reported herein are the over-all engine performance and the starting and windmilling characteristics. Data are presented in the form of performance maps at each flight condition to show the effects of altitude and flight Mach number on various engine-performance variables. The effect of engine deterioration with operating time on performance is also discussed."

From Introduction: "The purpose of the present report is to present a comprehensive summary of theoretical investigations of comprehensible laminar boundary layers which have been carried out since 1949 at the Polytechnic Institute of Brooklyn under the sponsorship and with the financial assistance of the National Advisory Committee for Aeronautics. The results of these investigations are contained primarily in references 1 to 7."

From Introduction: "The present report presents the results of such an analysis as regards the longitudinal-stability and control characteristics of the various airplanes tested."

"With the use of Karman's integrated momentum equation for the boundary layer and data on the wall-shearing stress and heat transfer in forced-convection flow, a calculation was carried out for the flow and heat transfer in the turbulent free-convection boundary layer on a vertical flat plate. The calculation is for a fluid with a Prandtl number that is close to 1. A formula was derived for the heat-transfer coefficient that was in good agreement with experimental data in the range of Grashof numbers from 10sup10 to 10sup12" (p. 1).

"Four 90 degree two-dimensional turning passages designed by the method of characteristics were tested at an inlet Mach number of 1.71. The measured losses varied from 5 to 15 percent of the inlet stagnation pressure. The smallest loss was obtained for a passage in which separation on the convex surface was minimized through the introduction of a favorable pressure gradient" (p. 1).

From Introduction: "This report extends the short-bearing pressure-distribution function of Michell and Cardullo to give equations for the various bearing characteristics. This short-bearing approximation makes available formulas relating eccentricity ratio to applied load, attitude angle, angular position of peak film pressure to unit pressure on projected area."

From Introduction: "Analyses that provide a basis for comparing the centrifugal-stress distributions inherent in jet-engine turbine blades of several designs currently in use were therefore made and are presented."

From Introduction: "An extension of the work presented in reference 2, the method was applied to six swept-wing airplanes for which the pilot opinion was well documented. The analytical results obtained are used herein to illustrate how wind-tunnel data may be used to predict the pitching motions and the comparative pitch-up behavior of new airplane designs or to assess the effects of modifications on existing airplanes."

"The material given in this report summarizes some of the results of recent research that will aid the designers of an airplane in selecting or modifying a configuration to provide satisfactory stability and control characteristics. The requirements of the NACA for satisfactory flying qualities, which specify the important stability and control characteristics of an airplane from the pilot's standpoint, are used as the main topics of the report. A discussion is given of the reasons for the requirements, of the factors involved in obtaining satisfactory flying qualities, and of the methods used in predicting the stability and control characteristics of an airplane" (p. 1).

An investigation was conducted to determine the behavior of recently produced, forged S-816 turbine blades in a full-scale turbojet engine, and in particular, the scatter in performance of the alloy. The turbine blades were operated as continuously as possible at a temperature of 1500 degrees F and a centrifugal stress of 21,500 pounds per square inch. The operating lives of the turbine blades varied from 181 to 539 hours, a range of 358 hours. Stress-rupture properties of specimens cut from blade airfoils also varied considerably, as much as 1257 hours at 20,000 pounds per square inch and 1500 degrees F. Since the variability of scatter of stress-rupture data is greater than that of blade performance, the scatter is probably caused by variations in the properties of the forged blades rather than by variations caused by engine operation or installation of the blades. Metallographic examinations were made to determine possible causes of the scatter and although numerous differences in microstructures of blades were found, no consistent tendencies were observed and the findings did not permit an explanation of the scatter of blade performance. The results of the metallographic examinations and of the physical tests indirectly indicated variables in the fabricating method …

"A series of calculations of the dynamic response of airplane wings to gusts were made with the purpose of showing the relative response of a reference airplane, the DC-3 airplane, and of newer types of airplanes represented by the DC-4, DC-6, and L-49 airplanes. Additional calculations were made for the DC-6 airplane to show the effects of speed and altitude. On the basis of the method of calculation used and the conditions selected for analysis, it is indicated that: 1) The newer airplanes show appreciably greater dynamic stress in gusts then does the reference airplane; 2) Increasing the forward speed or the operating altitude results in an increase of the dynamic stress ratio for the gust with a gradient distance of 10 chords" (p. 1).

From Summary: "Tests and calibrations of an AWS instrument shelter were made in the Langley 300 MPH 7- by 10-foot tunnel for the Signal Corps, U.S. Army. The behavior of the wind vane, the 3-cup anemometer, and the shelter cover was determined in wind speeds up to 150 miles per hour. It was discovered that the rotational speed of the anenometer was greatly influenced by the location, with respect to the wind direction, of three spacer posts that held two upper bays of instruments above the anenometer."

"A general method has been developed for calibrating strain-gage installations in aircraft structures, which permits the measurement in flight of the shear or lift, the bending moment, and the torque or pitching moment on the principal lifting or control surfaces. Although the stress in structural members may not be a simple function of the three loads of interest, a straightforward procedure is given for numerically combining the outputs of several bridges in such a way that the loads may be obtained. Extensions of the basic procedure by means of electrical combination of the strain-gage bridges are described which permit compromises between strain-gage installation time, availability of recording instruments, and data reduction time" (p. 1).

Report presenting an experimental investigation of the cooling characteristics of a small air-cooled turbine blade for use in a turboprop engine in a static cascade facility. Three test blades of the same size and chord were tested at several different combustion-gas temperatures. Results regarding the gas-flow conditions in cascade test section, correlation of temperature data and application of correlated data to typical engine are provided.