From Introduction: "The objectives of this report are to present methods and information sufficient for a lineralized dynamic description of the significant dependent and independent variables of a turboprop engine."

Report presenting an investigation in the 8- by 6-foot supersonic wind tunnel at several free-stream Mach numbers for a range of primary-nozzle pressure ratios and secondary weight-flow ratios to determine the effects on performance of varying the ejector diameter ratio by simulated iris flaps. Results indicated that increases in ejector gross force and secondary-to-primary total-pressure ratio were obtained subsonically when diameter ratio was reduced, thus reducing overexpansion losses.

Report presenting an investigation to determine the effects of altitude and inlet-pressure distortions on the steady-state and surge characteristics of the J57-P-1 two-spool turbojet engine in the altitude wind tunnel. Steady-state performance and surge fuel flows were obtained with a uniform inlet distribution at a range of altitudes at flight Mach number 0.8.

Report presenting an analysis of losses occurring in a series of subsonic turbine blades in a low-speed two-dimensional cascade and in a related series of four transonic rotors. Results regarding the two-dimensional cascade loss correlations, transonic turbine loss correlations, effect of unsteady flows, and mixing of stator wakes are provided.

Report presenting a review of NACA research on slurry fuels through 1954. Slurry fuels are defined as suspensions of metals in hydrocarbons, which may offer more flight range or thrust than can be obtained with conventional hydrocarbons. Magnesium is the primary metal of interest at this time for high thrust and boron for long-range flight.

Report presenting testing of a rocket-propelled model of an airplane with an arrow wing with a 55 degree leading-edge sweep and a flat-sided fuselage mounting swept horizontal and vertical tails using the pulsed-control technique at a range of Mach numbers. Results regarding longitudinal trim, lift and stability, drag, lateral force, and thrust and jet effects are provided.

"Measurement of the jet thrust of a turbojet engine in flight becomes more difficult as the number and complexity of the engine components increase. It is desirable, therefore, that a general correlation of jet thrust be developed which is applicable to a simple direct reading thrustmeter. In view of this need a correlation is presented which is independent of flight conditions and applicable to both non-afterburning and afterburning engines equipped with nonejector type fixed- and variable-area convergent exhaust nozzles" (p. 1)

"A bibliography of NACA papers on rotating-wing aircraft issued up to July 1948 is presented. The list of papers is subdivided for ready reference under appropriate subject headings, and the titles are listed chronologically within each subject" (p. 1).

"The hydrodynamic characteristics of a flying-boat incorporating a low-drag, planing-tail hull were determined from model tests made in Langley tank number 2 and compared with tests of the same flying boat incorporating a conventional-type hull. The planing-tail model, with which stable take-offs were possible for a large range of elevator positions at all center-of-gravity locations tested, had more take-off stability than the conventional model" (p. 1).

An investigation was conducted to determine the effect of the inlet Mach number and entrance-boundary-layer thickness on the performance of a 23 degree 21-inch conical-diffuser - tail-pipe combination with a 2:1 area ratio. The air flows used in this investigation covered an inlet Mach number range from 0.17 to 0.89 and corresponding Reynolds numbers of 1,700,000 to 7,070,000. Results are reported for two inlet-boundary-layer thicknesses.

Memorandum presenting a free-flight investigation conducted on four supersonic nose inlets. Each inlet used conical-shock and isentropic-compression center bodies; two of the models had internal contraction and two did not. Results regarding drag coefficient, pressure recovery, mass-flow ratio, and Reynolds number range are provided.

From Summary: "The present investigation was conducted to determine, from low-speed tests in the Langley stability tunnel, the static and rotary derivatives of a 1/9-scale model of the Republic F-91 airplane and various of its components (including the effects of wing incidence) and to determine the accuracy with which the period and damping of the lateral oscillation of the airplane could be calculated by using these experimentally between flight and calculated period and damping of the lateral oscillation were made for Mach numbers from 0.4 to 0.9 at an altitude of 20,000 feet for 0 degrees wing incidence and several other wing incidences. Some comparisons were made of the static and rotary derivatives of the model and derivatives estimated by available procedures."

Report presenting testing of a twin-duct air-intake system mounted on the sides of a fuselage forebody model at free stream Mach numbers of 1.5 and 2.0 over angles of attack and yaw. Results regarding the inlet survey, compression-surface boundary-layer removal and effects of second-ramp position, instability, effect of cant on inlet performance, inlet performance with 0 degree and 30 degree second-ramp angles, performance with fixed second-ramp angles, and effect of canards are provided.

Report presenting an investigation at Mach numbers of 1.79 to 2.67 on a wing-fuselage combination and on the wing-fuselage combination with a complete tail configuration. Two wing plan forms were investigated on the fuselage, which differed in sweepback and taper ratio.

"For about the past year, American Airlines has been engaged in obtaining data on various uses of airborne radar under routine operating conditions. This work is under contract to the Navy Department, Bureau of Ships, and includes the investigation of radar as a navigational aid and terrain collision warning device and its use in icing and turbulence detection. In view of the work of the National Advisory Committee for Aeronautics on atmospheric turbulence, the NACA was requested to participate in the tests to the extent of obtaining and evaluating the turbulence data for use in the turbulence-detection phase of the work" (p. 1).

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from June 11, 1947 to July 11, 1947 are presented.

Memorandum presenting the results of experimental and theoretical data on nine cowls to determine the effect of initial lip angle and projected frontal area on the cowl pressure drag coefficient at Mach numbers from 1.90 to 3.88. Results regarding the surface pressure coefficients, pressure distributions, effect of lip angle, projected cowl area, and Mach number on the cowl pressure drag coefficients are provided.

Report presenting an investigation in the high-speed tunnel to determine the effect of spin on the aerodynamic characteristics of a 60-millimeter T-24 mortar shell with several different tail-fin configurations. Tests were made at a range of airspeeds, speeds of rotation, and angles of attack. Results regarding forced-spin tests, free-spin tests, and zero-spin tests are provided.

Report presenting an investigation of an inlet with combined external and internal supersonic compression, formed by spike and cowl oblique shocks, and an overall length of 2.5 inlet diameters at a range of Mach numbers over a range of angles of attack. With proper boundary layer control on the centerbody, this method of internal compression did not adversely affect the high performance of the inlet.

"The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of a scout-bomber airplane. Comparisons are made between the root bending-moment and section torsional-moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending-moment coefficients but considerable disagreement for the torsional-moment coefficients" (p. 1).

"The performance of a 2.8 KS 8100 Cajun solid-propellant rocket motor has been determined from the free-flight test of a single-stage model which reached a velocity of 5,268 feet per second (Mach number, 4.74). Thrust data from the flight test are compared with data obtained from a ground firing test made by the manufacturer and the two are shown to be in agreement." Report presenting general drag, data, and acceleration are also provided.

Report presenting an investigation of the buffet characteristics of a model of an attack airplane at a variety of Mach numbers. The wing had a modified delta plan form with two NACA airfoils, a leading-edge sweep of 41.11 degrees, an aspect ratio of 2.91, and a taper ratio of 0.226. Results regarding frequency spectrum of bending moment, effect of density on root-mean-square bending moment, system damping coefficients, and buffet input force are provided.

Report presenting the wing-section pressure-distribution and wing-panel load characteristics of the Douglas D-558-II airplane for a range of Mach numbers and airplane normal-force coefficients. At subsonic speeds, the pressure distributions are characterized by a high negative-pressure peak with an abrupt pressure recovery as a result of the leading-edge expansion over the upper surface at moderate angles of attack.

"The flexural vibration of a rotating propeller blade with clamped shank is analyzed with the object of presenting, in matrix form, equations for the elastic bending moments in forced vibration resulting from aerodynamic forces applied at a fixed multiple of rotational speed. Matrix equations are also derived which define the critical speeds end mode shapes for any excitation order and the relation between critical speed and blade angle. Reference is given to standard works on the numerical solution of matrix equations of the forms derived" (p. 1).