05-09-2011: 0.5 hr
Just drilled the rudder horn brace, and found the edge margin is less than the desired 2D. This is a common problem for this part after searching Vansairforce.net. Many people choose to replace the part. The edge margin is now 1.7D, and Van's reply to other's similar problem is "just build on" (Can search Vansairforce.net for Vans's answer to similar question on R-710). I choose to do a quick analysis to see if the shorter than ideal edge margin is acceptable or not, for both static and fatigue load. Analysis results showed that the part is OK with E/D=1.7. The analysis detail can be found in "Construction Deviation and Analysis" section.
Short edge margin at these holes
for 2D edge margin, 6/32 is desired. Actual is 5/32
for 2D edge margin, 6/32 is desired. Actual is 5/32
