None

Operation of the D and F Piles is reported. Other items reported are: general; water, corrosion and engineering (graphite expansion).

There were no cases of unusual blistering of slugs being followed under Production Tests. Two normal production tubes were borescoped following trouble with discharge. In Tube 3188-D a distorted slug became stuck in the region of sharp curvature near the inner end of the rear gun barrel; this is the first time this phenomenon has occurred. Examination of irradiated slugs of rolled metal after normal exposure indicates that rolled material has no particular advantages over extruded material from the standpoint of blistering. However, no extensively blistered pieces were found in either the rolled metal are being held for more extended exposure. Inspection of a large number of Van Stone flanges in the D and F Piles has confirmed that the inlet flanges are in generally good condition but that the rear Van Stone flanges of tubes in the 0.140-inch orifice sone of both piles were badly corroded and generally contained deep pits that extended about half-way through the flange. The Van Stone test units are to be installed unshielded in the risor room at the rear of the D Pile, since the shielding required in the X Sample Room exceeded the allowable floor loading. Recent experimental observations indicate that solid …

This monthly report details Engineering Department technical activities for the month of May 1947.

None

None

None

None

Apparatus, field layout, miscellaneous testing, and the method of analysis of a 100-ton test at Trinity.

Abstract: The velocity of sound at the time of 100-ton shot at Trinity was measured to be 1116.1 ft/sec. Values of blast pressure computed from the excess velocity are given, but are not considered as reliable.

Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.

Report presenting an investigation of the characteristics of partial-span spoilers located at 0.75 of the chord on an NACA 66-series tapered wing, especially at high speeds. The effect of small spoiler projections was found to increase with an increase in speed until the critical Mach number was exceeded.

Report presenting theoretical pressure distributions and experimental aerodynamic characteristics at low speeds for a group of NACA four-digit series airfoil sections. Results regarding lift, drag, and pitching moment are provided.

From Introduction: "Recent investigations have indicated several wing plan forms, wing sections, and wing-body-tail combinations suitable for flight at supersonic speeds. One such lifting surface, a thin, sharp-edged without sweep of aspect ratio 4 and taper ratio 0.5, has been the subject of an investigation in the Ames 12-foot pressure wind tunnel. The aim of the investigation was to determine the aerodynamic characteristics of such a wing plan form throughout the range of subsonic Mach numbers up to 0.94."

From Introduction: "Although the aerodynamic characteristics of the components of such configurations may be well known, the mutual interference resulting from combining the wings, as well as the wings and body, may be so great that is desirable to study the aerodynamic properties of the complete configurations. Two methods of handling this problem are presented in this report. The first method is essentially an extension of the theory for slender wing-body combinations of reference 1 to determine the load distribution, forces, and moments exerted on slender cruciform-wing and body combinations inclined simultaneously at small angles in pitch and yaw. "

Report presenting tests made in the LMAL 16-foot high-speed tunnel to determine the aerodynamic characteristics of a 1000-pound AN-M-65-AZON radio-controlled bomb at a Mach number range of 0.2 to 0.6. Over the Mach number range, the hinge-moment coefficients, yawing-moment coefficients, and lateral-force coefficients exhibited no important changes with increasing speed.

From Introduction: "An investigation of the power-plant installation of a single-engine torpedo-bomber-type airplane has been conducted in the NACA Cleveland altitude wind tunnel at the request of the Bureau of Aeronautics, Navy Department. A similar investigation was previously conducted on a three-tenths scale mock-up of the forward portion of the fuselage of this airplane in the Langley 20-foot tunnel. (See reference 1)."

This short analysis may be useful in determining the real tactical possibilities of "glider trains" and in adopting the course to be followed in possible studies of these questions. In this analysis most prominent are: (a) the power required for the train in level flight; (b) its speed; (c) climb; and (d) the type of airplane best suited for towing as well as design requirements for transport gliders.

"In the present paper, under the same lineaeizing assumptions as are made in the derivation in reference 1 but with the explicit consideration and simplification of the form of the wake extending from the rear of the airfoil, the methods of Theodorsen (reference 2) have been extended to obtain the forces on the airfoil not only at a fixed angle of attack but also in arbitrary motion" (p. 1).

Report is a brief summary of investigations on symmetrical and cambered airfoils in the DVL high-speed tunnel. Some information on the effects of low aspect ratio are also included.

None

"An altitude-test-chamber investigation was conducted to determine the operational and performance characteristics of a McDonnell afterburner with a fixed-area exhaust nozzle on a J34 engine. At rated engine speed, the altitude limit, as determined by combustion blow-out, occurred as a band of unstable operation of about 6000-foot altitude in width with minimum altitude limits from 31,000 feet at a simulated flight Mach number of 0.40 to about 45,500 feet at a simulated flight Mach number of 1.00. Considerable difficulty was experienced in attempting to establish or maintain balanced-cycle engine operation at altitudes above 36,000 feet" (p. 1).

From Introduction: "Thrust augmentation of an axial-flow-type turbojet engine by burning fuel in the tail pipe is discussed in references 1 to 3. Thrust augmentation of the same turbojet engine by water injection at the compressor inlet is reported in reference 4."

Technical report. Areas covered are properties of uranium halides, properties of uranium nitrides, and hydride formation at high pressure.