Breaking-Strength and Endurance Tests of Aluminum Turnbuckles for Aircraft

摘要

Breaking-strength and endurance tests were run to make possible a partial evaluation of the strength of turnbuckle bodies fabricated from 2024T6 aluminum alloy. Aircraft control cable turnbuckles and fittings were exposed to extremes of temperature, salt water spray, buffeting, and low-amplitude high-frequency vibration. Failures in the aluminum bodies occurred at the transverse hole drilled through the middle of the body. When the aluminum body is modified so that the opening area is 0.057 inch, failures at the transverse hole can be eliminated. Tests of brass and aluminum bodies showed that the ratio of average tensile strength to weight of aluminum bodies was 61 percent better than for the brass bodies. When aluminum barrels were used instead of brass barrels, a saving of approximately 7 pounds could be realized for bodies used with a cargo or bomber type aircraft. (Author)