Memorandum presenting rudder-pulse maneuvers performed with a swept-wing fighter-type airplane at altitudes from 30,000 to 43,000 feet over a Mach number range of 0.71 to 1.48 to determine the lateral stability characteristics relative to the stability axes, in general, and the lateral derivative characteristics, in particular. Four configurations were employed; three involves different vertical tails with varying aspect ratio or area and the fourth employed a large tail with an extension of the wing tips.

This report describes tests of 10 full-scale metal propellers of several thickness ratios at various tip speeds up to 1,350 feet per second. The results indicate no loss of efficiency up to tip speeds of approximately 1,000 feet per second. Above this tip speed the loss is at a rate of about 10 per cent per 100 feet per second increase relative to the efficiency at the lower speeds for propellers of pitch diameter ratios 0.3 to 0.4. Propellers having sections of small thickness ratio can be run at slightly higher speeds than thick ones before beginning to lose efficiency.

Memorandum presenting an investigation of a double-ramp cascade inlet at Mach number 3.05 in order to determine the penalties associated with decreasing the length of inlets by means of cascades. Total-pressure recovery and profile distortion of the cascade inlet were compared with a similar single-passage inlet that captured the same mass flow.

Report presenting an analysis of the blade-element performance of a highly loaded transonic rotor with double-circular-arc blades. The rotor was purposely loaded beyond the prudent level for exploratory purposes. Results regarding the radial-distribution plots, blade-element data, element blade-to-blade loss variation, and a comparison of steady-state and hot-wire measurements are provided.

A method is described for calibrating airspeed installation on airplanes at transonic and supersonic speeds in vertical-plane maneuvers in which use is made of measurements of normal and longitudinal accelerations and attitude angle. In this method all the required instrumentation is carried within the airplane. An analytical study of the effects of various sources of error on the accuracy of an airspeed calibration by the accelerometer method indicated that the required measurements can be made accurately enough to insure a satisfactory calibration.

This report presents the results of a series of wind tunnel tests showing the force, moment, and autorotational characteristics of Clark Y airfoils having aspect ratios varying from 0.5 to 3. An airfoil of rectangular plan form was tested with rectangular tips, flared tips, and semicircular tips. Tests were also made on one airfoil of circular plan form and two airfoils of elliptical plan form. The tests revealed a marked delay of the stall and a decided increase in values of maximum lift coefficient and maximum resultant force coefficient for aspect ratios of the order of 1 as compared with values for aspect ratios of 2 and 3.

Compilation of the papers presented at a NACA conference on transonic airplane design, including stability and control and configurations with extreme sweep. From Introduction: "The purpose of this conference was to convey to those involved in the study of the aerodynamic problems of transonic aircraft these recent research results and to provide those attending an opportunity for discussion of the results."

"This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results" (p. 6).

Memorandum presenting a survey and evaluation of flutter research and flutter engineering, with particular emphasis placed on the design of primary fixed surfaces and primary controls. Analyses are made of recent flutter occurrences to delineate past and future problems, and detailed appraisals are given of the status of the various engineering branches involved in the analytical and experimental prediction of flutter.