Long Term Durability of Urea Formaldehyde Glued Joints Removed from Vampire Aircraft.

摘要

Two Vampire fuselages originally manufactured in 1950 were used for the Australian Aeronautical Research Lab.'s Vampire Wing Fatigue Tests carried out between 1960 and 1965. The Vampire fuselage is of laminated wooden monocoque construction using spruce, improved wood and aircraft plywood, bonded with Urea Formaldehyde glue. After completion of the wing fatigue tests a number of wooden specimens were removed from these fuselages and stored under ambient laboratory conditions until Sept. 1983. At the time of specimen removal, the fuselages had been subjected to a total of 67,238 and 42,279 hours actual flying and simulated life. Careful inspection of the fuselages before removal of the specimens revealed on indication of any defect indicating that design strength requirements were not being met. This report describes the condition of the wooden joints from these specimens, broken open in Sept. 1983. At this time the glue bonds had reached a life of 33 years. This report concludes that long term exposure (18 years) of these wooden specimens to an ambient laboratory environment had not led to any significant deterioration of the Urea Formaldehyde bonded joints, and that after 33 years since manufacture the joints were still satisfactory.