Note presenting axial fatigue tests made by the resonance method on 10 specimens from airplane wing beams. The specimens contained several types of stress raiser, such as rivets, holes, fittings, splices, reinforcing plates, and so forth. The results show a greater fatigue stress concentration factor for the wing-beam specimens than for drilled coupons machined from the flanges or for parallel strip coupons containing idle rivets.

Results are presented of tests for determining the tensile, compressive, and bending properties of a material of plastic-bonding glass cloth and canvas layers. In addition, 10 panel specimens were tested in compression. Although the material is not satisfactory for primary structural use in aircraft when compared on a strength-weight basis with other materials in common use, there appears to be potential strength in the material that will require research for development. These points are considered in some detail in the concluding discussion of the report. An appendix shows that a higher tensile strength can be obtained by changes in the type of weave used in the glass-cloth reinforcement.

Report presenting an apparatus for making quantitative measurements of the vibrations excited by detonation in the cylinder head of an aircraft engine. The apparatus consisted of pick-up units, an amplifying system, and a cathode-ray oscillograph with a high-speed-camera recording system. A large number of records were taken under various operating conditions in a single-cylinder aircraft engine.

Note presenting tests conducted on 5 uncoated steels and 20 steels with various coatings to determine the effect of temperature on the tensile properties and surface characteristics of the metals. The metals were subjected to furnace-heating tests over a range of temperatures for various times and to flame-impingement and airplane-fire tests. Results regarding metals without surface coatings, low carbon steels with surface coatings, and discussion of comparative behaviors regarding the different surface coatings are provided.

Note presenting a method of deriving certain airfoil shapes that delay certain compressibility phenomena, and the aerodynamic data for a wide range of Mach numbers obtained from tests of the airfoils in the 24-inch high-speed tunnel. The airfoils, which are designated the NACA 16-series, have increased critical Mach number. Results regarding the airfoil comparison, critical speed, minimum drag, and use of the data are provided.