This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).

Symbols and definition of various airspeed terms that have been adopted as standard by the NACA subcommittee on aircraft structural design are presented. The equations, charts, and tables required in the evaluation of true airspeed, calibrated airspeed, equivalent airspeed, impact and dynamic pressures, and Mach and Reynolds numbers have been compiled. Tables of the standard atmosphere to an altitude of 65,000 feet and a tentative extension to an altitude of 100,000 feet are given along with the basic equations and constants on which both the standard atmosphere and the tentative extension are based.

Report presenting the results of tests to determine the effect of taper on the zero-lift drag of wings of constant exposed aspect ratio at low supersonic speeds. Findings indicated that maximum thickness, leading-edge, and trailing-edge sweep are all important in determining the drag coefficient of a tapered wing.

The flow fields near a 45 degree swept-wing-fuselage combination at moderate angles of sideslip (plus-or-minus 8 degrees), as determined experimentally at low speed, are presented as variations with chordwise distance for various spanwise and vertical locations and angles of attack. The results indicated that for positions close to the fuselage (on and near the plane of symmetry) changes in the angle of sideslip caused large changes in the flow-field characteristics and particularly in the local angles of sideslip, which in some cases were nearly double the static angle of sideslip.

Report discusses the results of an experimental investigation of two low-drag wing-nacelle units suitable for use with pusher propellers. The benefits of adding a nacelle to the wing are detailed.

Report presenting a consideration of the development of the laminar boundary layer in a compressible fluid. Formulas are given for determining the boundary-layer thickness and the boundary-layer Reynolds number, which is a measure of the boundary-layer stability, for airfoils and bodies of revolution.

Four models with longitudinal steps on the forebody were developed by modification of a model of a conventional hull and were tested in the National Advisory Committee for Aeronautics (NACA) tank. Models with longitudinal steps were found to have smaller resistance at high speed and greater resistance at low speed than the parent model that had the same afterbody but a conventional V-section forebody. The models with a single longitudinal step had better performance at hump speed and as low high-speed resistance except at very light loads. Spray strips at angles from 0 degrees to 45 degrees to the horizontal were fitted at the longitudinal steps and at the chine on one of the two step models having two longitudinal steps. The resistance and the height of the spray were less with each of the spray strips than without; the most favorable angle was found to lie between 15 degrees and 30 degrees.

"A method is presented for the computation and graphic representation of a series of possible turbine designs for any specific application. The use of a preliminary design chart is suggested for determining the number of stages and the effects of exit whirl and annular-area divergence on possible configurations. A specific design chart can then be made to aid in the study of the relations between turbine radius ratio, diameter, and significant design parameters such as Mach numbers, turning angles, and blade root stresses" (p. 1).

Note presenting a consideration of a wing-selection problem sometimes encountered in the preliminary design of supersonic airplanes and missiles. The problem is to determine the span, section thickness ratio, and skin thickness or hollowness ratio of the wing of least drag when the plan form, section shape, wing lift requirement, and flight conditions are assumed known. An example of the application of the method to a diamond wing at Mach number 2.0 for a range of specified flight conditions is presented.

The charts presented give the compressive buckling coefficients for a single-truss-core and a double-truss-core sandwich plate. These charts cover a wide range of sandwich proportions and may be used for sandwiches with unequal faces. They apply to inplane compressive loads acting parallel or perpendicular to the core direction or for various combinations of these loads. (author).

"Charts giving the compressive-buckling stress coefficients for sheet panels of a shape occurring in swept-wing plan forms are presented. The panels are assumed to be a part of a continuous flat sheet divided by nondeflecting supports into parallelogram-shaped areas. The stability analysis was performed by the energy method and the results show that, over a wide range of panel aspect ratio, such panels are decidedly more stable than equivalent rectangular panels of the same area" (p. 1).

This report contains the flight-test results of the longitudinal-stability and -control phase of a general flying qualities investigation of the Lockheed P-80A airplane (Army No. 44-85099). The tests were conducted at indicated airspeeds up to 530 miles per hour (0.76 Mach number) at low altitude and up to 350 miles per hour (0.82) Mach number) at high altitude. These tests showed that the flying qualities of the airplane were in accordance with the requirements of the Army Air Forces Stability and Control Specification except for excessive elevator control forces in maneuvering flight and the inadequacy of the longitudinal trimming control at low airspeeds.

Memorandum presenting an investigation of flow deflectors which extend forward of an open-nose inlet for improving positive angle-of-attack performance and auxiliary scoops for use at off-design engine air-flow conditions at low angles of attack to determine their effect on net inlet performance. The results show that a deflector inlet and a basic open-nose inlet have about the same net performance at low angles of attack although the flow steadiness characteristics of the deflector inlet are the less desirable.

Report presenting testing of a low-acceleration transonic flutter test vehicle to obtain flutter data on two similar sweptback wings which indicated that wing flutter was symmetrical in mode. Results regarding flight and flutter characteristics for the FR-1-B are provided.

Note presenting an investigation of the effects of tip dihedral on lateral stability and control characteristics by flight tests of models in the free-flight tunnel. The results indicate that at high lift coefficients, tip dihedral may cause a lightly damped lateral oscillation, which does not occur with full-span dihedral at similar values of effective dihedral and directional stability.

The problem before us is to determine the total stresses in an axially loaded column of any degree of restraint which is also subject to transverse bending both from a uniformly distributed load and from concentrated loads. The solution of this problem is of special importance in the design of aircraft which consist of slender columns" (p. 1).

From Summary: "The problem of developing a windshield for aircraft which will withstand the effect of bird impacts during flight is a difficult one, as an estimate of the striking energy will indicate. If the average speed of the airplane is considered to be about 200 miles per hour and that of the bird about 70 miles per hour, the speed of the bird relative to the airplane may be as great as 400 feet per second. If a 4-pound bird is involved, a maximum impact energy of approximately 10,000 foot-pounds must be dissipated. To obtain this energy in a drop test in the Washington Monument, it would be necessary to drop a 20-pound weight down the 500-foot shaft. For both theoretical and practical reasons, it is necessary to keep the mass and speed more nearly like those to be encountered. However, to get an impact of about 10,000 foot-pounds with a 4-pound falling body, it would be necessary to drop it from a height of approximately one-half mile, neglecting air resistance. These facts will indicate some of the experimental obstacles in the way of simulating bird impacts against aircraft windshields."

From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number and to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."

Report presenting characteristic exhaust-velocity measurements made of the JP-4 fuel-red fuming nitric acid propellant combination in 40-pound-thrust rocket engines with various combustion-chamber lengths and diameters. The results are compared to those from previous studies and discussed in terms of a vaporization model of combustion. Results regarding the effect of UDMH, effect of water on performance of hydrocarbon fuels, effect of water on performance of hydrazine fuel, and some of the chemical and physical factors affecting combustion are provided.

Report presenting a note in two parts regarding simplified truss stability criteria. The first part covers the development of simplified criteria for the stability of planar pin-jointed trusses against buckling in the plane of the truss. The second part constitutes a report on tests carried out to verify the validity of the criteria developed in part one.

Report presenting tests of the extent of laminar flow that can be obtained with practical wing-surface conditions. Chemical sublimation was used for boundary-layer-flow visualization on the wings of a supersonic fighter airplane in level flight. A method of continuous monitoring using heat temperature resistance gauges was also used on one wing.

Chemical sublimation has been employed for boundary-layer-flow visualization on the wings of a supersonic fighter airplane in level flight at speeds near a Mach number of 2.0. The tests have shown that laminar flow can be obtained over extensive areas of the wing with practical wing-surface conditions. In addition to the flow visualization tests, a method of continuously monitoring the conditions of the boundary layer has been applied to flight testing, using heated temperature resistance gages installed in a Fiberglas "glove" installation on one wing. Tests were conducted at speeds from a Mach number of 1.2 to a Mach number of 2.0, at altitudes from 35,000 feet to 56,000 feet. Data obtained at all angles of attack, from near 0 deg to near 10 deg, have shown that the maximum transition Reynolds number on the upper surface of the wing varies from about 2.5 x 10(exp 6) at a Mach number of 1.2 to about 4 x 10(exp 6) at a Mach number of 2.0. On the lower surface, the maximum transition Reynolds number varies from about 2 x 10(exp 6) at a Mach number of 1.2 to about 8 x 10(exp 6) at a Mach number of 2.0.

"Results are presented of an investigation to determine the pressure distributions on a wing with leading-edge sweepback decreasing from 45 degrees at the root to 20 degrees at the tip, an aspect ratio of 4.12, taper ratio of 0.36, and NACA 64A009 airfoil section. Tests were conducted at a Reynolds number of 3.5 x 10(exp 6) and a Mach number of 0.07 on the wing with and without 0.20 chord and 0.65 span split flaps deflected 60 degrees. These pressure distributions are analysed herein to determine the character of flow and its effect on the stability of the wing" (p. 1).

Report presenting an experimental investigation of thrust augmentation of an axial-flow-type turbojet engine with a 4000-pound-thrust rating using a water-alcohol injection at the compressor inlet at sea-level conditions and zero ram. Three injection systems were investigated in order to obtain satisfactory atomization and distribution of the injected liquids. Results regarding engine performance and engine operation are provided.