The aerospace sector, like most manufacturers, have traditionally used more, or larger bolts, than is strictly necessary in their assembly, in order to offset the effect of poor control of the bolted joint. With ever increasing pressure to design lighter structures to increase fuel efficiency, this practice is fast becoming obsolete.
Over-bolting is not confined to the aerospace sector. Even the humble car wheel uses four or five bolts to secure the wheel, when in reality the job could be done with fewer and smaller bolts if greater control was applied. This reduced un-sprung weight of the car would also, as a result, improve the acceleration, braking and ride quality of the car.
Similarly, in the aircraft industry, the cost of over-design, particularly its effect on fuel efficiency is even more noticeable. The rule of thumb is that a 1% weight reduction results in 0.75% reduction in fuel consumption; therefore a considerable saving potential.
Over 80% of the fully laden take-of ...
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