Report discussing an investigation of the DM-1 glider, which has an approximately triangular plan form, with auxiliary studies of a model of triangular wings. The pitching-moment coefficient, drag coefficient, and angle of attack with the lift coefficient are provided. Results indicated that the angles of descent without power are likely to be prohibitive and airplanes with the tested type of wings will not be able to land safely without power.

Rim cracking in turbine wheels with welded blades was evaluated. The problem is explained on the basis of the occurrence of plastic flow in the rim during transient starting conditions when thermal compressive stresses resulting from high-temperature gradients exceed the proportional elastic limit of the material.

Four routine shutdowns were experienced during the month. A measurable amount of the excess reactivity held in the control rods at the first of the month has been lost in the decrease in the average accumulated exposure of all the metal in the pile. The vertical safety rod guides have been measured for vertical alignment by the Maintenance Dept. A definite pattern has been found in the misalignment of the guides. The horizontal rod thimbles were borrowed on January 2, 1947 to see if any leaks were present. No leaks were observed but No. 2 Rod and No. 8 Rod had heavy gouge marks along the longitudinal axes. Several thimbles contained white corrosion. During the month two new bismuth tubes were established, 2871-D and 2877-D. This now gives the desired pattern of ten bismuth tubes.