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In the early part of last year, the author was asked to examine and report on a number of welded test pieces. These test pieces were cruciform joints in T.45 tube, and had been oxy‐acetylene welded by skilled aircraft welders using DTD. 82A (soft iron) filler rod and had been tensile tested. The tubes were rather larger than are commonly met with in aircraft practice, being 1½ in. o/d and 16G. and 10G. in thickness. Some of the test joints comprised tubes of equal thickness and others of unequal thickness. The lighter gauge tubes were generally satisfactory, all failures occurring in the tube away from the welds, but the heavy gauge tubes all failed in the welds and showed that difficulty had been experienced in obtaining adequate penetration without the welds becoming over‐heated and of excessive size. These indications were still more pronounced in the joints comprising tubes of unequal size in that, in spite of all failures occurring in the lighter gauge tubes, the latter suffered from excess penetration and some oxidation, and the welds on the heavy tubes lacked penetration and were in parts defective. These findings suggested that oxy‐acetylene welding was not suitable for this particular application.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Technical Reports and Translations of the United States National Aeronautics and Space Administration and publications of other similar Research Bodies as issued.

Contrary to the general conception of adding weight for fatigue resistance it is sometimes possible to reduce the fatigue hazard by removing weight. The theory of having bearing area, tear‐out area, and tension area sufficient to develop the full shear strength of a rivet is not necessarily sound when fatigue life is considered. Accordingly, marked improvements in fatigue resistance can be achieved by reducing the underlying areas to such an extent that they are incapable of inducing loads causing fatigue failures of the main structure. Results of tests involving fatigue failure are given, and seven basic considerations in the design of fatigue resistant structures are listed.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Technical Reports and Translations of the United States National Aeronautics and Space Administration and publications of other similar Research Bodies as issued.