Report presenting equations for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of the satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling, and to prevent flutter.

Report presenting a survey of the technical information contained in the literature on the subject of lubrication, friction, and wear of aircraft engine piston rings.

"An analysis is made to simplify pressure-drop calculations for nonadiabatic and adiabatic friction flow of air in smooth cylindrical tubes when the density changes due to heat transfer and pressure drop are appreciable. Solutions of the equation of motion are obtained by the use of Reynolds' analogy between heat transfer and skin friction. Charts of the solutions are presented for making pressure-drop calculations" (p. 1).

"Detail calculations are presented of the shifts in stick-fixed neutral point of the Republic XF-12 airplane due to the windmilling propellers and to the fuselage. The results of these calculations differ somewhat from those previously made for this airplane by Republic Aviation Corporation personnel under the direction of Langley flight division personnel. Due to these differences the neutral point for the airplane is predicted to be 37.8 percent mean aerodynamic chord, instead of 40.8 percent mean aerodynamic chord as previously reported" (p. 1).

From Summary: "Local-instability tests of 24S-T aluminum-alloy formed Z- and channel-section columns were made in order to determine a length of test specimen that would avoid the increased strength associated with short lengths and also permit the occurrence of a convenient buckling pattern. The effect of column length on the critical compressive stress, on the average stress at maximum load, and on the number of half-waves of the buckling pattern is shown."

Report presenting testing to determine the best way to land the B-25 airplane in calm and rough water and to determine its probable ditching performance. By landing with flaps down in a tail-down attitude at as slow a speed as possible, smooth straight landing runs will probably result in calm water. Results regarding the effect of attitude, effect of flap setting, effect of simulated damage, effect of propellers, and effect of seaway are provided.

Report presenting the application of transient theory to the rational determination of dynamic loads on airplane structures during initial landing impact. Simplified procedures are described by which the distribution of the maximum attainable value of the dynamic stresses in the structure may be obtained.

Report discussing the knock-limited performance of blends of triptane and 28-R fuel in an F-4 engine at three sets of conditions and three compression ratios. The knock limits of the triptane blends were more sensitive to compression ratio than the 28-R fuel, and the sensitivities of the blends increased as the severity of other engine conditions increased.

Report presenting an investigation made on a supercharged CFR engine to determine a method for estimating lead susceptibilities of pure or blended paraffinic fuels. As a result of these studies, a chart consisting of a series of straight lines passing through the origin was developed to represent the lead susceptibilities of pure and blended paraffinic fuels in terms of knock-limited indicated mean effective pressures and octane numbers.

"The importance of the stick force per unit normal acceleration as a criterion of longitudinal stability and the critical dependence of this gradient on elevator hinge-moment parameters have been shown in previous reports. The present report continues the investigation with special reference to transient effects for maneuvers of short duration" (p. 449).

Report presenting an investigation of the relation between the knock limit and the blend composition of aviation fuels when tested under supercharged conditions in an air-cooled aircraft-engine cylinder. Results regarding the blending characteristics of two gasolines, paraffinic fuels, olefinic fuel, naphthenic fuel, aromatic fuels, when xylidines are present in the fuel components, and fuel components containing unequal concentrations of tetraethyl lead are provided.

None

This letter was written in 1944 and applies to the amount of radiation a person could be subjected to under emergency, wartime conditions. Mr. Stone recommends to Dr. Norwood that no man should be ordered to expose himself to more than a tolerance dose (0.1r in a 24 hr period) except in the case of an extreme emergency in which time is of the essence. And that before any man is asked to exceed tolerance that a radiation trained physician be called in for consultation. His recommendations to said physician are that: (a) a single exposure of 1r would cause no harm and could be repeated at long intervals, (b) an exposure of 5 to 10r would produce loss of appetite and nausea and would increase the chances of genetic change but would cause no clinically detectable changes after the incident, (C) an exposure of 25r would do the same as (b) but with greater probability -- he would be personally willing to take a 25r exposure to accomplish an extremely important job, (4) in general keep exposures well below tolerance, (5) due to the genetic effects, women of childbearing age and younger men should be subjected to none and …

Report presenting flight tests to determine the longitudinal stability characteristics of a pursuit airplane when flown with and without an experimental bellows-type bob weight. When the weight was installed, the stick-free static stability remained approximately constant irrespective of the shift in center of gravity resulting from a change in fuel quantity in the auxiliary fuselage fuel tank. Although the weight functioned satisfactorily, the performance could have been enhanced by the reduction of the friction in the mechanism.

Report presenting the use of the Ackeret iteration process to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient.

Report presenting an investigation of the icing and de-icing characteristics of a Pratt & Whitney R-1830 engine induction system. The current report covers a program to determine the most effective rate and method of injection of de-icing fluid to remove a heavy ice formation from the induction system. Results regarding the flow rates, recovery times, de-icing portions of the runs, and ice formation characteristics are provided.

Report presenting an investigation of underslung cooling-air ducts in various locations on a model of a typical single-engine tractor airplane in the full-scale tunnel. The report contains the results of tests of two forward underslung ducts. Results regarding pressure recoveries at the radiator, pressures behind the radiator, drag and duct efficiency, and critical speeds are provided.

The problem of lining a hollow aluminum sphere, 10 inches i.d., with lunes of heavy metal foil, was assigned to this group by Dr. E. Creutz. The work was carried out under the direct supervision of Dr. D.H. Gurinsky. the problem was divided naturally into tow parts: first, forming fitting the lunes, and second, cementing hem to the inside of the sphere.

This barely legible document contains information on slug testing results and autoclave performance. Reactor physics, corrosion, chemistry and instrument development are also discussed.

This report documents the progress made for the week in each of the following areas: fuel canning operations; reactor operations (100 area); instrumentation development; and fuel reprocessing (200 area). Detailed information is given for each of these areas. Problems encountered are also discussed.

"The theory of heat.transfer from a solid body to a liquid stream could he presented previously only with limiting assumptions about the movement of the fluid (potential flow, laminar frictional flow). (See references 1, 2, and 3). For turbulent flow, the most important practical case, the previous theoretical considerations did not go beyond dimensionless formulas and certain conclusions as to the analogy between the friction factor and the unit thermal conductance, (See references 4, 5, 6, and 7,) In order to obtain numerical results, an experimental treatment of the problem was resorted to, which gave rise to numerous investigations because of the importance of this problem in many branches of technology" (p. 1).

"The lubrication of a piston ring is treated as though the ring were a rigid slider of finite width. An expression is obtained for pressure distribution which takes into account the effect of oil leakage from the ends of the ring and which has the convenient form of an end correction to the pressure-distribution formula for an infinite slider. The important formulas are summarized for convenience and two examples are included of their use in finding the pressure pattern over wide sliders" (p. 1).

Report presenting problems relating to the stability and control of tailless airplanes in consideration of contemporary experience and practice. Some observations in regards to small and large airplanes are provided.

The following report describes and foretells the situation in medium in which neutrons are being (a)produced as fast neutrons, (b) slowed down to thermal speeds by impacts with nuclei, and (c) absorbed by nuclei in such a manner that sometimes fresh fast neutrons appear at the place where a thermal neutron has just appeared.