SB 14-01-31; RV-6, 7, 8

[wrongway john]

Quite a long thread, and have only went through half of it thus far. The SB states to ?Clean the area and remove any paint, overspray or primer that could hide a crack.? The pic that Van uses in the SB shows the crack without them removing the primer. Also noticed quite a few taking pics stating no cracks found, which didn?t bother to remove paint/primer either.

[magiccarpet]

I don't understand why enlarging the forward top most holes of the flanges of HS-405 from #40 to #27 in step nr. 13 of the SB.
Those holes aren't anymore for any good after the SB fix, are they? I can't see from the drawings.
I rather don't want to enlarge them, 'cause they are already a tiny bit out of MED tolerance.
The most obvious reason I can imagine of, is to eliminate the 3/32 dimple around that holes. But why bother?

any ideas on that?

I probably should add that I haven't riveted the skin on the HS yet. Lucky me .So maybe that is why I don't understand the reason for step 13 yet.

[rvbuilder2002]

Originally Posted by magiccarpet

I don't understand why enlarging the forward top most holes of the flanges of HS-405 from #40 to #27 in step nr. 13 of the SB.
Those holes aren't anymore for any good after the SB fix, are they? I can't see from the drawings.
I rather don't want to enlarge them, 'cause they are already a tiny bit out of MED tolerance.
The most obvious reason I can imagine of, is to eliminate the 3/32 dimple around that holes. But why bother?

any ideas on that?

I probably should add that I haven't riveted the skin on the HS yet. Lucky me .So maybe that is why I don't understand the reason for step 13 yet.

After the inboard spar flange gets trimmed, there is a gap between the rib and the skin at the location of this hole. If a rivet is installed as is, it can suck the skin inward and the rib outward. Undesirable for both.
Structurally there is very little benefit having them riveted together, so the hole gets enlarged to allow filling the skin hole with a rivet, but not attach it to the rib.

[Geico266]

255 Hours
No cracks
No notches

Mild acro
Grass 40%

IO-360 195 HP
Constant speed

[magiccarpet]

Originally Posted by rvbuilder2002

After the inboard spar flange gets trimmed, there is a gap between the rib and the skin at the location of this hole. If a rivet is installed as is, it can suck the skin inward and the rib outward. Undesirable for both.
Structurally there is very little benefit having them riveted together, so the hole gets enlarged to allow filling the skin hole with a rivet, but not attach it to the rib.

That makes perfect sense. Thanks a lot for your explanation

[ao.frog]

RV-7 290 hrs
Notches per plans
No cracks

75 % pavement
20 % grass
5 % snow-covered ice rwy's

Lots of std acro maneuvers (max +4)
Lots of formation

10 % at MTOW

Superior IO-360
MT C/S prop dynamically balanced

Moved with towbar on TW

[B Cunningham]

RV7 225 hours
No cracks
Builder # 71313
Notches per the plans dimensions
Mild acro
-5% grass
Always pushed around with the empennage. I'm changing that habit...

[tracy]

Originally Posted by rvbuilder2002

After the inboard spar flange gets trimmed, there is a gap between the rib and the skin at the location of this hole. If a rivet is installed as is, it can suck the skin inward and the rib outward. Undesirable for both.
Structurally there is very little benefit having them riveted together, so the hole gets enlarged to allow filling the skin hole with a rivet, but not attach it to the rib.

Could you just use the cut out flange piece and use it for a spacer with a rivet?

[Mark Burns]

Originally Posted by tracy

Could you just use the cut out flange piece and use it for a spacer with a rivet?

You obviously haven't cut your flanges off yet :-)
They are not pretty. I needed a right angle dremmel.

And you're not really complying with the SB if you add your own twist.
Minor as it may be, it wouldn't fly in the certified world. No pun intended.

Mark

[bret]

Called Vans this morning inquiring about the repair kit. Apparently they sold out of the first batch pretty quick. Next week they should have the next batch ready to ship out she said. Just curious how many folk are doing the mod?