Steve serves as Senior Editor of Machine Design. He has 23 years of service and has a B.S. Biomedical Engineering from Steve was a Flight officer in the U.S. Navy. He is currently responsible for areas such as aerospace and medical.
Bolted joints are often tightened to 75% to 80% of bolt proof load. This amount of tightening, a rule of thumb, is suitable for many joints, but in some cases, external tensile loads can reduce bolt clamping force to zero.
As a follow-up to our recent image gallery, here are four more aircraft that have flown longer than most others. It could be because aircraft designers in the past tended to overdesign and use generous safety margins.