F-636 Shoulder Harness Anchor, DWG 26

I'm installing the F-636, Shoulder Harness Anchors
If it is located per plan, the 3/16" hole has 1/4" edge distance.
Is this another engineered edge distance violation?

I can get edge distance if it's placed at the vertex of the longeron instead of 1/8" inboard.
Advise is appreciated.

Edit...Ok. I feel stupid. Answer from Vans is get as close as possible but make sure the nut and washer can nest properly inside the longeron. Better to ask first than make scrap. Especially where the longeron is concerned.

Edge Distance

I had an interesting conversation with an aircraft mechanic about edge distances on bolt holes vs edge distance on rivets. He mentioned that the distances are different on bolts as the bolts do not exert the same stress on the hole like a driven rivet does. Makes sense to me, but I would love to hear a few thoughts on the matter.

Move anchor outboard by 1/16".

So I did some checking today for where to place these holes to limit edge distance issues. If you move the shoulder harness anchor 1/16" further outboard, this allows the washer to still sit flat on the underside of the longeron. It of course improves your inboard edge distance by 1/16", taking it to 1.66D. Not perfect, but 1/16" better than what it was. This positioning also lets you still use a standard socket on the nut.
Tom.

Aero_Octaveus said:

I had an interesting conversation with an aircraft mechanic about edge distances on bolt holes vs edge distance on rivets. He mentioned that the distances are different on bolts as the bolts do not exert the same stress on the hole like a driven rivet does. Makes sense to me, but I would love to hear a few thoughts on the matter.

Click to expand...

Aerospace stress analysis was my career, now retired, and the major differences I've seen relate to the tension load that bolts can develop, or the need to account for the effects of any clearances between the non-hole-filling bolts and the hole-filling rivets. In mechanisms, of course, there are additional issues.

But the edge distance requirements are independent of the type of fastener used, and typically are based on the strength required for the joint.

Dave