Report discussing an investigation of a parabolic body of revolution with and without the effects of an annular jet exhausting from the base. The aerodynamic characteristics, pressures, lift-curve slope, and other characteristics with the jet in operation and inoperative were compared.

Report discussing progress of the Metallurgical Project at the Massachusetts Institute of Technology for the term from October, 1949 through December, 1949.

From Introduction: "This paper presents the results of an investigation of force and moment characteristics for a wing with an unswept quarter-chord line, aspect ratio 2, taper ratio 0.78, and an NACA 65A004 airfoil section parallel to the free stream."

The following report provides data from completed tests for corrosion testing of stellite-T347 stainless steel test cylinders.

This report analyzes infrared absorption measurements that were made in the regions of carbonyl band and hydroxyl band absorptions on solutions of water in hexone and water in acetone, confirming intermolecular association of water and hexone.

Report presenting a theoretical study of the dynamic lateral stability characteristics of an airplane with a 60 degree triangular wing. Calculations included the determination of the neutral-lateral-oscillatory-stability boundary, the period and time to damp to one-half amplitude of the lateral oscillation, and the time to damp to one-half amplitude for the spiral mode. The airplane was generally found to be stable for all conditions.

From Introduction: "This paper presents the results of the investigation of the wing alone and of the wing-fuselage configurations employing a wing with an unswept quarter-chord line, aspect ratio 4, taper ratio 0.6, and an NACA 65A004 airfoil section parallel to the air stream. The experimental results of a wing of identical plan from having an NACA 65A006 airfoil section which was tested as part of the transonic program are presented in reference 1.

Report presenting an investigation concerned with the measurement of the characteristics of longitudinal-control devices for a wing-fuselage combination with a wing with the leading edge swept back 63 degrees. Most of the investigation was devoted to testing a 30-percent-chord, 50-percent-semispan elevon, but some used upper-surface spoilers. Results regarding the characteristics of the wing with the elevon undeflected and control-surface effectiveness are provided.

"An investigation was conducted at Mach number 1.90 to determine pressure recovery and mass-flow characteristics of series of perforated convergent-divergent supersonic diffusers. Pressure recoveries as high as 96 percent were obtained, but at reduced mass flows through the diffuser. Theoretical considerations of effect of perforation distribution on shock stability in converging section of diffuser are presented and correlated with experimental data. A method of estimating relative importance of pressure recovery and mass flow on internal thrust coefficient basis is given and a comparison of various diffusers investigated is made" (p. 1).

Abstract: An investigation was conducted to determine the absorption and translocation of fission products by Russian thistle from a localized spot of contaminated soil. The amount and identity of the radioactive elements absorbed and translocated by the Russian thistle is given along with the location of these elements in the plants. Beta radioactivity to the amounts of 10 microcuries per gram caused no visible effects on the growth habits of sectioned material are included.

Measurements have been at the Pajarito remote control laboratory to determine the effect of change of shape on system reactivity for oralloy cylinders. Systems tested include cylindrical configurations with various height-to-diameter ratios ranging from slabs to rods. Each system reactivity is referred to that of a sphere in the same tamper. Reactivity tests were made on bare (untamped) Oy configurations, as well as on systems In tuballoy tampers 1.12,1.87,and 8.0 thick. The amount of reactivity change associated with a particular cylinder height-to-diameter ratio is feud to be a function of tamper thickness, and is greatest for very thin tampers.

This investigation was begun as a result of a mass spectrometric measurement of two samples of tritium which had been stored for several months in Pyrex glass bulbs using stopcocks. The first of these was originally supposed to be of extremely high isotopic and chemical purity. What was observed at this time was 1.45 H had accumulated, and that tritiated methane, CT4, was also present to the extent of 0.18%. A consistent attempt had been made in this sample to protect the gas from contact with the grease by covering the stopcock with mercury. the second sample was a composite of T2 samples of various degrees of enrichment with an isotopic analysis of 92% T. No protection had been attempted during its storage, and 0.86% CT4 to be present.

"Existing conical-flow solutions have been used to calculate the hinge-moments and effectiveness parameters of trailing-edge controls having leading and trailing edges swept ahead of the Mach lines and having streamwise root and tip chords. Equations and detailed charts are presented for the rapid estimation of these parameters. Also included is an approximate method by which these parameters may be corrected for airfoil-section thickness" (p. 937).

Memorandum presenting an investigation conducted in the 20-foot free-spinning tunnel with a scale model to determine the spin and recovery characteristics of the McDonnell XF3H-1 airplane. The effects of control settings and movements on the erect and inverted spin and recovery characteristics of the model were determined. Results regarding design gross weight loading, variation of loading, spin-recovery parachutes, pilot escape, landing condition, control forces, and recommended recovery technique are provided.

Report presenting a wind-tunnel investigation of the low-speed static longitudinal characteristics of a model of the X-3 airplane with the wing flaps neutral and deflected. Results regarding those characteristics with the flaps neutral, with the flaps fully deflected, in the presence of a ground plane, with the flaps partially deflected, and effect of miscellaneous changes of the model are provided.

The following quarterly report covers the period of July through September of 1950, split into three reports discussing the metabolic properties of plutonium and allied materials, biological studies of radiation effects, and health chemistry and physics.

Report presenting a wind-tunnel investigation to determine propeller section aerodynamic characteristics by measuring surface pressure distribution on the airfoil sections of a rotating propeller. The pressures were measured at nine radial sections of the NACA 10-(3)(08)-03 two-blade propeller. Results regarding sectional critical Mach number, and aerodynamic coefficients are also presented.

Report presenting an investigation of the low-speed lateral characteristics of a 47.5 degree sweptback-wing-fuselage combination with several flap and spoiler aileron arrangements. Results regarding aileron control characteristics, spoiler-control characteristics, and a comparison of the two are provided.

From summary: "The methods of calibrating the 305 pile for impurities and density differences in graphite are reviewed and calibration constants are calculated theoretically."

Memorandum presenting calculations made to determine the deceleration at any time after jettisoning of an airplane nose-section design typical of those which have been proposed as escape devices for high-speed airplanes. The decelerations were determined by two methods, one using successive approximations requiring graphical integration and the other giving reasonably close approximations by direct computation.

Report presenting an investigation at a Mach number of 1.24 using the NACA wing-flow method to determine the longitudinal-control effectiveness and downwash characteristics of a scale semispan model of the variable-sweep Bell X-5 airplane with the wind swept back at several different degrees. Lift, drag, and pitching moments were obtained for various angles of attack for several horizontal tail settings and with the tail off for each angle of sweep of the wing.

Technical report covering experiments to measure the resonance and absorption of neutrons in U238 cylinders. Report also discusses control problems connected to the Bulk Shielding Facility and work on MTR controls.

Since the 25 content of the uranium to be used in a MTA multiplying lattice is quite uncertain at present, it is necessary to assume various degrees of depletion in order to estimate the multiplication constant K-o and the production of 49 in an infinite uranium-graphite lattice

"This report summarizes the effects of fuel volatility and engine design variables on the problem of starting gas-turbine engines at sea-level and altitude conditions. The starting operation for engines with tubular combustors is considered as three steps; namely, (1) ignition of a fuel-air mixture in the combustor, (2) propagation of flame through cross-fire tubes to all combustors, and (3) acceleration of the engine from windmilling or starting speed to the operating speed range. Pertinent data from laboratory researches, single-combustor studies, and full-scale engine investigations are presented on each phase of the starting problem" (p. 1).