What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Blind drilling center bottom skin to wing skin

K

KayS

Well Known Member
Hey All,

drawing 38 shows on the right side the attachement of the wing root fairing. It also shows the connection between the fuselage's F-776 center bottom skin and the wing's W-704 bottom inboard skin. The empty holes in the wing skin are already set but the fuse skin doesn't have holes yet. So you can't see the holes of the wing skin. How to make sure to hit these holes? Is there a trick?


Cheers, Kay
 
KayS said:
Hey All,

drawing 38 shows on the right side the attachement of the wing root fairing. It also shows the connection between the fuselage's F-776 center bottom skin and the wing's W-704 bottom inboard skin. The empty holes in the wing skin are already set but the fuse skin doesn't have holes yet. So you can't see the holes of the wing skin. How to make sure to hit these holes? Is there a trick?


Cheers, Kay
Click to expand...

I just did this the other day :D

The trick is, before the wings are fitted for the first time, take a ruler and mark a line from the center of the hole, out about 4”. When the wings are on, you can use a ruler to measure exactly 4” from the end of the visible line to the hole center.

If your wings are already on, you can use a strap hole finder but the skins are pretty tight and it might be difficult to get the hole finder under the skin.
 
Wing skin to fuselage skin holes

Its been a while and I have a 9A but it should be the same,with the wings temporarily in place take a #40 12? bit and insert it into the top hole of the wing and while looking down insert into the punched hole in the fuselage center skin and drill out. Do all holes the same both sides. When wings are removed drill to I believe #8 holes and dimple. Plans call for measuring but this worked good. Tough to see in the wing root but with lots of light it worked. Hope this helps, Dave
 
Future RV 9 Flyer said:
Its been a while and I have a 9A but it should be the same,with the wings temporarily in place take a #40 12? bit and insert it into the top hole of the wing and while looking down insert into the punched hole in the fuselage center skin and drill out. Do all holes the same both sides. When wings are removed drill to I believe #8 holes and dimple. Plans call for measuring but this worked good. Tough to see in the wing root but with lots of light it worked. Hope this helps, Dave
Click to expand...

On the -7 you can do that method for a couple of the holes but the rest, not so much. Also, in my case, edge distance was of concern on one wing (?? at least) and drilling from the top would have busted the minimum.
I had to bias some os the holes outboard to get my minimum.
 
:eek:

Oh S..T!!! then i would have to remove the wings twice. which, in my case, was not the most pleasant experience.

Will try to find a way to drill from top.
 
KayS said:
:eek:

Oh S..T!!! then i would have to remove the wings twice. which, in my case, was not the most pleasant experience.

Will try to find a way to drill from top.
Click to expand...

If your wings are on for the initial fitting and don't have the close tolerance bolts installed do this.

Pull the temporary bolts and slide the wing out BUT not all the way. Only pull the wing out enough to expose the bottom of the wing lower skin where the holes are, leaving the spar still in the center section. There will still be plenty of spar in the center section. AND if you did not use grease or spray lube on the spar...do it now.
Make sure the wing is supported while you do this.

Doing this will allow you to draw the lines to the hole centers and it should be easy to push the wing back in.

Here's an EAA video describing how to do the hole location measurement. I think you need an EAA account to view it.
 
thanks for the inputs! yesterday i found a much easier way when looking at the situation:

every third hole on the top wing skin is still empty, These holes are for the platenuts that attach the fairing later. you can easily put a long #40 drill bit through the holes to hit and matchdrill the holes on the bottom. you can even see clearly where you're aiming at, as the side skin of the fuse acts like a mirror. The holes will be a bit aslant, but that doenst matter as you will enlarge them later anyway.

easy peasy! :)
 
You must log in or register to reply here.
Back
Top