"An approximate theory of buffeting is here presented, based on the assumption of harmonic disturbing forces. Two cases of buffeting are considered: namely, for a tail angle of attack greater and less than the stalling angle, respectively. On the basis of the tests conducted and the results of foreign investigators, a general analysis is given of the nature of the forced vibrations the possible load limits on the tail, and the methods of elimination of buffeting" (p. 1).

Flight and ground investigations have been made to compare an exhaust-ejector installation with a standard exhaust-collector-ring installation on air-cooled aircraft engines in a twin-engine airplane. The ground investigation allowed that, whereas the standard engine would have overheated above 600 horsepower, the engine with exhaust ejectors cooled at take-off operating conditions at zero ram. The exhaust ejectors provided as much cooling with cowl flaps closed as the conventional cowl flaps induced when full open at low airspeeds. The propulsive thrust of the exhaust-ejector installation was calculated to be slightly less than the thrust of the collector-ring-installation.

"Tests were conducted in the Langley 24-inch highspeed tunnel to ascertain the static-pressure and total-pressure losses through screens ranging in mesh from 3 to 12 wires per inch and in wire diameter from 0.023 to 0.041 inch. Data were obtained from a Mach number of approximately 0.20 up to the maximum (choking) Mach number obtainable for each screen. The results of this investigation indicate that the pressure losses increase with increasing Mach number until the choking Mach number, which can be computed, is reached" (p. 1).

An extensive investigation of the changes of the local and mean heat-transfer coefficients along the pipe length, and some results.

Report discussing an investigation into the stalling characteristics, aileron effectiveness, and longitudinal stability of a scale model of the XB-36 airplane. The model was tested with the original configuration as well as with several modifications to the outboard panels and flap arrangement.

Report presenting the results of flight testing to determine the zero-lift drag of an NACA 65-009 airfoil at a specified aspect ratio. The results are compared to previous testing of unswept and swept-back arrangements. The swept-forward and swept-back airfoils were found to produce lower values of zero-drag lift than the unswept airfoil.

Report presenting tests to determine the effects of sweepback angle and aspect ratio on the drag of an NACA 65-009 airfoil at supersonic speeds. The results indicated that for the range of Mach numbers investigated, increasing the sweepback angle and decreasing the aspect ratio reduced the value of the wing drag coefficient.

Report discussing an investigation to determine the effects of changes in aspect ratio and tail height on the longitudinal stability characteristics of a model with a 32.6-degree sweptback wing. The effects of a leading-edge discontinuity were also examined.

A series method of determining two-dimensional vortex paths is considered and applied to the computation of vortex positions behind a slender equal-span cruciform wing at any angle of bank as a function of the distance behind the trailing edge. Calculated paths are shown for four bank angles. For a bank angle of 45 degrees comparison is made with the results of a closed expression given in NACA-TN-2605. For other bank angles water-tank experiments provide qualitative comparison. Satisfactory agreement is found for a sufficient distance downstream to include most practical missile-tail positions. The interference forces on an equal-span cruciform wing are calculated for five angles of bank (including the trivial case of zero bank) from the vortex positions found by use of the series.

Report presenting tables for determining the total-absorption coefficients as well was the intensities and spectral distribution of gamma rays at any scattering angle. Both experimental and computed data on gamma rays of quantum energies up to 20 million electron volts for all elements which have significant data available are provided. The accuracy of results is obtained by the use of tables.

A model of one of the twin hulls of the Italian Savoia S-55-X flying boat (N.A.C.A. Model 46) was tested in the N.A.C.A. tank according to the general method. The data obtained from these tests cover a broad range of speeds, loads, and trims and are given in nondimensional form to facilitate their use in applying this form of hull to any other flying boat or comparing it's performance with the performance of any other hulls. The results show that the resistance characteristics at best trim of this model are excellent throughout the speed range. In order to compare the performance of the S-55-X hull with that of the 35, a pointed-step hull developed at the N.A.C.A. tank, the data are used in the computations of take-off example of a twin-hull, 23,500-pound flying boat. The calculations show that the S-55-X hull has better take-off performance.

Report discussing the knock-limited performance of blends of 2,3-dimethylpentane and 23-R fuel in an F-4 engine at three sets of conditions and three compression ratios. The knock-limited performance of 2,3-dimethylpentane has about the same sensitivity to compression ratio and inlet-air temperature as 28-R fuel.

The variation of dielectric constant has been measured as a function of the concentration of magnesium particles; the shape, size, and degree of oxidation of the particles; the temperature; and the frequency of oscillation. The variation of dielectric constant and settling rate was investigated as a function of time. Also investigated were the effects of particle concentration, shape and time on dielectric losses.

From Summary: "The data from previous NACA pressure-distribution investigations of plain flaps and tabs have been analyzed and are presented in this paper in a form readily applicable to the problems of control-surface design. The experimentally determined variation of aerodynamic parameters with flap chord and tab chord are given in chart form and comparisons are made with the theory. With the aid of these charts and the theoretical relationships for a thin airfoil, the aerodynamic characteristics for control surfaces of any plan form with plain flaps and tabs may be determined. A discussion of the basic equations of the thin-airfoil theory and the development of a number of additional equations that will be helpful in tail design are presented in the appendixes. The procedure for applying the data is described and a sample problem of tail design is included."

From Introduction: "The present report gives all the results, including those published in reference 1 and the results of previously un-published tests tests of the airfoils at positive angles of attack."

From Summary: "This report contains the lift, drag, and moment characteristics of tapered Clark Y, Gottingen 393, and USA 45 airfoils as obtained from tests made in the Variable Density Wind Tunnel of the NACA. The results are given at both low and high Reynolds Numbers to show scale effect and to provide data for use in airplane design."

From Introduction: "The results of varying only Reynolds number for several equivalent tip speeds are presented and probable reasons for the apparent variation of adiabatic efficiency with inlet temperature are discussed."

Report presenting tests to determine the flight characteristics of an F-86A airplane equipped with an area-suction boundary-layer-control system on the flaps and to investigate the possible operational problems which may arise on a flight installation of boundary-layer control. Results regarding the airplane with slatted leading edge, suction requirements, airplane with suction flap and various leading-edge configurations, factors affecting flap lift increment, and operational characteristics of boundary-layer control are provided.

Report presenting flight measurements on a swept-wing jet aircraft to determine the effects of adding forward camber and an increased leading-edge radius on the low-speed stalling characteristics, the high-speed static longitudinal stability, and the airplane drag. The modified leading edge produced values of maximum lift somewhat greater than the slats on a normal airplane, but the stall was unacceptable because of an abrupt roll-off.

Note presenting an investigation of the fatigue characteristics of riveted joints in aluminum alloy sheet. The purpose of this report is to summarize all the results of fatigue tests that have been made to date in the Aluminum Research Laboratories of lap joints with 1/8-inch aluminum alloy rivets.

Report presenting information regarding transient oscillations observed in response to elevator pulses of the Douglas D-558-I airplane at a range of Mach numbers and altitudes. An application of the Fourier transform was used to obtain the frequency-response characteristics. The effects of lift coefficient on the frequency response are also included.

Report discussing testing of a Douglas D-558-II to investigate its longitudinal stability characteristics in accelerated flight at supersonic speeds. Information about the normal-force coefficients and their relation to stability and pitch-up of the aircraft is included.

"Results are presented of a free-flight investigation between Mach numbers of 0.7 to 1.3 and Reynolds numbers of 3.1 x 10(exp 6) to 7.0 x 10(exp 6) to determine the longitudinal aerodynamic characteristics of the Northrop MX-775A missile. This missile has a wing, body, and vertical tail, but has no horizontal tail. The basic wing plan form has an aspect ratio of 5.5, 45 deg of sweepback of the 0.406 streamwise chord line, and a taper ratio of 0.4" (p. 1).

Memorandum presenting results of a free-flight investigation over a range of Mach and Reynolds numbers to determine the longitudinal aerodynamic characteristics of the Northrop MX-775A missile. The missile has a wing, body, and vertical tail, but has no horizontal tail. Results regarding basic data, drag, trim, lift and static stability, damping, and static pressure are provided.