This report presents test results of experiments on the vibration-response characteristics of airplane structures on the ground and in flight. It also gives details regarding the construction and operation of vibration instruments developed by the National Advisory Committee for Aeronautics.

This report gives the results of an investigation conducted in the NACA full-scale wind tunnel on a small parasol monoplane equipped with three different split trailing-edge wing flaps. The object of the investigation was to determine and correlate data on the characteristics of the airplane and flaps as affected by variation in flap chord, flap deflection, and flap location along the wing chord. The results give the lift, the drag, and the pitching moment characteristics of the airplane, and the flap forces and moments, the pressure distribution over the flaps and wing at one section, and the downwash characteristics of the flap and wing combinations.

From abstract: "Experiments covering the coprecipitation of Thorium and Uranium peroxides are described on synthetic and actual 1300 cycle machine wash effluents."

"It is shown how Schrenk's empirical method of estimating the lift distribution over straight wings can be adapted to swept wings by replacing the elliptical distribution by a new "ideal" distribution which varies with sweep.The application of the method is discussed in detail and several comparisons are made to show the agreement of the proposed method with more rigorous ones. It is shown how first-order compressibility corrections applicable to subcritical speeds may be included in this method" (p. 1).

Report presenting an investigation of the damping-in-roll characteristics of a 35 degree sweptback wing, with and without vertical fins, through a range of Mach numbers in the high speed 7- by 10-foot tunnel utilizing a free-to-roll technique. The damping-in-roll coefficient increased in magnitude with Mach number in the manner indicated by theory and generally was found to increase in magnitude with angle of attack over the range tested.

"An investigation is made of the buckling of the compression cover of post-stiffened box beams subjected to end moments. Charts are presented for the determination of the minimum post axial stiffnesses and the corresponding compressive buckling loads required for the compression cover to buckle with nodes through the posts. Application of the charts to design and analysis and the limitations of their use are discussed" (p. 1087).

A numerical method was developed for calculating thermal stresses in irregular cylinders cooled by one or more internal passages. The use of relaxation methods and elementary methods of finite differences was found to give approximations to the correct values when compared with previously known solutions for concentric circular cylinders possessing symmetrical and asymmetrical temperature distributions.

Quarterly technical report including reports on chemistry of source, fissionable, and structural elements, nuclear chemistry, radio-organic chemistry, chemistry of separations processes, chemical physics, radiation chemistry, and instrumentation. [From Abstract]

The total cross sections of the reactions DDp, DDn, TD at 10 kev to 10 Mev are estimated from a review of the experimental data up to January 1951. Maxwell averages for DDp and TD computed from these estimates are given, together with some fitted analytic expressions provided for machine use. A collection of the identifiable earlier estimates is also included for reference and for comparison with the new figures. For relative order of magnitude purposes, cross sections and the derived Maxwell averages are given down to 50 ev using the theoretical Gamow slopes for the extrapolation. Gamow plots for the derived cross sections above l0 kev arc also given. Much of the primary experimental data exists in the form of thick target yields and we find the most uncertain factor in converting these thick targets yields into cross sections is the magnitude of the D/sub 2/O stopping cross section. The particular D/sub 2/O stopping cross section relation used in this derivation together with some of the earlier stopping cross sections are given. Thick target yields are included for both DD and TD on D/sub 2/ targets, at 0.01 to 1 Mev, experimental values being supplemented by calculated values.

Abstract: "Decontamination factors of the order of 10-4 were obtained for Beta and Gamma emitters present as fission products when uranium was precipitated from 50 mC activity level solutions as uranyl oxalate under normal uranium yield conditions for three cycles (~60%). Factors of the order of 10-3 were obtained by the use of this reaction with similar solutions under relatively high uranium yield conditions for three cycles (~90%). The uranium peroxide precipitation reaction proved to be of no value on such solutions, yielding decontamination factors of only 17.1 Beta emitters and 1.2 for Gamma emitters for three cycles."

Theoretical performance for liquid lithium and liquid fluorine as a rocket propellant was calculated with assumptions both of equilibrium and frozen composition during expansion. Parameters included were specific impulse, combustion-chamber temperature, nozzle-exit temperature, composition, mean molecular weight, characteristic velocity, coefficient of thrust, and ratio of nozzle-exit area to throat area. For chamber pressure of 300 pounds per square inch absolute and expansion to 1 atmosphere, the maximum equilibrium specific impulse calculated was 335.5 pound-seconds per pound. The effect of ionization on calculated performance was shown to be negligible by comparison of values of various parameters calculated both with and without ionized products of combustion.

Report presenting an investigation to determine the aerodynamic characteristics of a series of thin, rectangular wings in the 16-foot high-speed wind tunnel using the transonic bump technique over a range of Mach and Reynolds numbers. Lift, drag, and pitching moment characteristics are presented for wings of 4 different aspect ratios and NACA 63A0XX sections and with 5 different thickness-to-chord ratios.

Fourier analyses are made on two functions. The first is a step function forward from periodic samples of a sinusoid. If the frequency of the sinusoid is less than one-half of the sampling frequency, it is shown that the step function has no frequency components less than one-half of the sampling frequency other than that of phase, and duration with respect to the interval of the analysis. It is shown that the insertion of a blank space in the period of analysis reduces greatly the uncertainty of the amplitude of the initial sinusoid as estimated from the results of the Fourier analysis. The results of the analyses are useful in the design and evaluation of certain analog data-analyzing systems.

A knowledge of the mechanical and physical properties of uranium is important in understanding and explaining its pile behavior. The effects of irradiation on the properties of uranium will be dealt with in another chapter. However, it is important to know and understand the pre-irradiation properties of uranium prior to investigating the effects of irradiation.

Report presenting some experimental and theoretical studies of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams as a way to investigate problems associated with propulsive jets. A variety of variables for each case are considered, including jet Mach number, nozzle divergence angle, jet static-pressure ratio, free-stream Mach number, and specific heat ratios.

Ultrasonic equipment has been developed for nondestructive testing of Hanford fuel elements. The ultrasonic method has replaced the Frost Test for bonding layer inspection in the Hanford canning line, and provides more accurate and reliable results at lower cost. The method has also been adopted to the testing of new fuel elements for which no other method is available.

Report describing the design and flight evaluation of an air-borne target simulator using precomputed relative kinematics for use in tracking studies of fighter aircraft equipped with scope-presentation type fire-control systems. Testing occurred in an F86D airplane equipped with a Hughes E-4 fire-control system. Results regarding relative kinematic programming considerations and restrictions to system evaluation are provided.

Report describing experiments to evaluate the effectiveness of various kinds of shelters to protect occupants from nuclear and thermal radiation and blast effects.

Report presenting an investigation conducted with trimethyl borate azeotrope and pentaborane fuels in a turbojet combustor. The primary purposes of the study were to determine the effect of boron oxide deposits on the turbine-nozzle area, combustor pressure loss, temperature distribution, and combustion efficiency. Three distinct boron deposit patterns were noted in the investigation.

Report presenting an investigation to determine some effects of tail damping and wing-tail interference on the rolling effectiveness of ailerons and a spoiler on a modified-delta wing. Results regarding the effect of adding fixed tail surfaces, effect of moving the horizontal tail out of the plane of the wing, and a comparison with theory are provided.

Report presenting free-flight tests of two rocket models at a range of Mach numbers to determine the control rolling effectiveness and system operation of an autorotating-vane spoiler on a missile configuration with an 80 degree delta, cruciform wing. Results indicated that the system operated fairly satisfactorily as a flicker-type roll control except at low supersonic speeds.

"An investigation has been conducted in the Langley Unitary Plan Wind tunnel to determine the static stability and drag characteristics of a 1/10-scale model of the AVCO booster vehicle. The tests were made at a constant Reynolds number, based on maximum nose diameter, of 1.09 x 10(exp 6)6 at Mach numbers of 1.60 and 2.00" (p. 1).

Report discussing the performance of an experimental quarter-sector annular combustor at conditions simulating supersonic flight of a cooled-turbine engine, as well as 20 different modification to the design. The final configuration was found to show no structural failures and little or no warping of liner parts after 40 hours of operation.

The measurements reported here are companion measurements to those reported earlier in HW-63585. The only significant difference between the measurements is that 1.8 w/o enrichment UO2 fuel was used for the first set, and 2.6 w/o enrichment UO2 fuel was used for the measurements described in this report. The new results will be presented graphically, and for completeness, the details of the measurement will be included here as well as in HW-63585.