Maybe I can add a little with regard to minimum edge distance:? First, I would suggest that honoring minimum edge distance values is generally routine in the fabrication and repair of all types of aluminum aircraft and the reported Boeing rule is right in line with what I have seen elsewhere. The Jeppesen book "Aircraft Sheet Metal" gives a minimum edge distance of 2D.? "Aircraft Structural Technician" written by Dale Hurst provides a 2D minimum edge distance value but additionally gives a 2.5D value for countersunk rivets.? A minimum edge distance value of 2D can also be found in AC 43.13.? I'm not sure how Boeing defines their rule, but for these other three references, the distance is measured from the center of the hole to the edge of the material.
I think that these values are typically taken to apply to flat materials.? I'm not sure how these guidelines might fit the more complex cross sectional geometry of our spar caps. Cheers, Bill William Bayne said:? I would be reluctant to attempt to apply such a rule directly to light aircraft.
