wrench1,
Interesting story about the BO-105 and the rope. The D-spar is solid aluminum. I've been thinking of a way to jig the blade so a hole can be bored from tip toward the root so a tungsten rod can be inserted. Your idea about placing a strip on the leading edge that conforms to the original airfoil shape is worth investigating. An additional advantage would be that steel would hold up better to erosion than the existing aluminum.
chopjock,
Only one bolt like the Jetranger.