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Wingwalk doubler

Bavafa

Well Known Member
The plan instructs to CS the top skin for the wingwalk doubler and I was wondering if there is a reason that one should or could not dimple both the skin, doubler and the ribs.
 
Same instructions on the RV-10.

I dimpled the RV-10 skins, doubler and ribs, and did the same on a set of RV-14 wings I made. I’m happy with the result.

Carl
 
Same

I also disagreed with that step on the RV14 plans as it makes a knife edge on the countersink edges. Completely agree that dimpling is the way to go here, but both methods do work. I have not heard of any negative consequences of either method.
 
+1 for dimpling the wing walk ribs/doubler/skins, worked great on my -8A and -14A. And when you get to the fuel tanks, do yourself a favor and dimple the aft baffle flanges & outer skin there as well.

My rule of thumb is to always dimple if possible...countersink only when dimpling is impossible.
 
Thank you all for responding, it seems the concensess are to dimple instead of CS. So, this is what I will plan on doing unless there is a compelling reason offered to do CS
 
The QB wings I received last January were dimpled instead of CS in that location which is against what the manual states. Upon a phone call to Van’s tech support, they were okay with the dimpling method.
 
I did the C/S and the edges were a little raised. When we sanded for paint it was super smooth and flat after. So there is a slight aesthetic difference.
 
Thank you all for responding, it seems the concensess are to dimple instead of CS. So, this is what I will plan on doing unless there is a compelling reason offered to do CS

If we specify a specific process in the construction manual it is always for a specific reason;)

Having said that, it is not always the only way to do something but we specifically choose one method after evaluating the options.

In this case it is for two reasons....

1. - Some builders do not do as good of a job of dimpling as could be done. This usually doesn't have a negative influence on the nesting of parts, but in this instance, it is 3 layers in a highly loaded area of the wing so M. C. was chosen to minimize the influence of that.

We are fully aware that mach. countersinking .032 material causes a knife edge on the hole which is why in Section 5 we specifically state that we recommend doing so for 3/32 rivets only on .040 or thicker material.
This is intended as a general rule of thumb that in very specific circumstances we may choose to deviate from (this case and a portion of the fuel tank skins being the only instances that I can think of at the moment).
As already mentioned, the area is flat enough that dimple countersinking all 3 parts is acceptable if the dimples are well formed.

2. - A slight reduction in dimpling work that needs to be done. The machine countersinking can be done when the skin and doubler are put into place for riveting
 
Scott,
Thank you for explaining the reason, I suspected that might have been the reason after you explaining the reason for the tank skin to be CS. Based on that and the info here, I am planning on making sure all dimples are formed well and of the same quality, since I have already dimpled the ribs and it will probably not be advisable to undimple so many holes on the wing ribs.
My C-frame/table do a very nice job of dimpling.
 
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