Minimum Edge Distance

ShortSnorter · #1 11-13-2016, 04:13 PM

While finishing up section 16, I managed to smear one the last 1/8" rivet. I decided to drill it out and replace it, which went as planned. Driving the second rivet, I clinched the tail and now HAD drill out the rivet again.

As the story goes the hole became oblong in the W-1014 aileron hinge bracket assembly only and none of the other sandwhiched layers.

I then decided to upsize the hole to 5/32 to get rid of the oblong hole. Now, the problem is that I am 1/16" short on edge distance. Is 1/16" that critical or should I rebuild the hinge bracket assembly?

60av8tor · #2 11-13-2016, 04:17 PM

Merely my opinion, but edge distance is edge distance. Easier to correct now or once complete and you find a crack in the bracket?

wirejock · #3 11-13-2016, 04:18 PM

I wouldn't even ask. That's a critical part and probably not very expensive.

ShortSnorter · #4 11-13-2016, 04:40 PM

After second thought, even if I rebuilt the hinge bracket, the bottom hole on the bracket would require 5/32" sizing since the underlying double and rear spar are already drilled to 5/32". I guess I shouldn't have been so drill happy

JonJay · #5 11-14-2016, 08:16 AM

2x dia. is a rule of thumb. Check the mil specs. You get a little more tolerance than 2x, but it may not solve this issue. If it doesn't, call Van's.
https://www.vansaircraft.com/public/Specs.htm
You are allowed .281 edge margin for non flush rivets, which is a lot closer than .3125 (5/16). I assume these are non flush rivets that go here?
Measure with calipers. You might have what you need.

Marc Bourget · #6 11-14-2016, 04:10 PM

Are you measuring the distance from the edge of the material to the closest edge of the rivet hole - or from the edge to the center of the rivet?

Check your edge distance rules. Mil STD-403C defines Edge distance as measured from the centerline of the rivet to the edge of the sheet or joint.

For a 5/32 rivet you would need .3125 from the edge. If you have .250 from edge of sheet to edge of hole, your centerline measurement would give an edge distance of .328125"

FWIW

ShortSnorter · #7 11-14-2016, 04:34 PM

I consulted with the mother ship today and came to the following conclusions:

-Since the aileron hinge brackets come pre drilled with exactly 1/4" edge distance, there would never be enough room to upsize the hole.

-Three options exist:
1) Replace the part along with the entire rear spar
2) Take the bracket off and cut the inner flange off and attempt to replace it with angle.
3) Set the single 5/32" rivet and check periodically after being service

In case anyone was wondering, I am going to opt for option 3.

I did however, order the inboard hinge bracket SB parts, so at least I'll get to drill some rivets out. One thing I learned was that the SB is not required on the outboard brackets due to the way they are mounted (spar and side of the end rib) and there haven't been any reports of issues on the outboard side.