Wing root fairing advice

[szicree]

I'm getting ready to do my wing root fairings using metal strips instead of the fiberglass deal that came with my 4 kit. Unfortunately this means I have to work largely without plans, so I have several questions for those that have done their wing roots.

1. On the screws that go through the tank, I assume that they are all the way inboard and only go through the tank skin and not the inboard tank rib. Is this correct?

2. What gets countersunk, what gets dimpled, and which nutplates (k1000 or k1100) are used?

3. I understand from Dan's site that the aft-most tank holes double as fairing mount holes. True?

4. On the top of the wing, exactly how far aft does the fairing go? Does it stop even with the aft edge of the upper wing skin or does it get involved somehow in fairing the flap?

5. How much of a gap should there be between fairing and fuse?


Thanks so much in advance for any answers you guys (and gal?) can provide.

Steve Zicree
RV4 finishing??? Boy, that's a hot one!

[Hawkeye7A]

I don't have my plans right in front of me as they are at a buddy's BIG garage while I've been fitting my wings. The fairings run from the trailing edge of the main skin on top to a point just past the trailing edge of the tank skin on the bottom. I also drew a line 1/4" or 5/16" from the inboard edge of the tank skin and parallel to it to use for aligning the pre-punched holes in the fairing. According to the building instructions the holes in the top of the wings get c'sunk(I assume because you have three layers of aluminum here with the walkway reinforcement) and K1000-08 nutplates. All around the tank skins the holes are dimpled and you use K1100-08 nutplates. And yes, it's true that the inboard corner tank attach screws(both top and bottom) double as attachment points for the fairing. I waited until I had all the wing holes drilled and clecoed before I made the trimming line on the inboard edge of the fairings. The plans say to trim the fairing 3/16-1/4" from the side of the fuselage. Interestingly enough when I removed both caps from my double-tipped Sharpie pen and laid in flat against the fuselage it made the mark with the thin tip at exactly 7/32" ! Perfect enough. It was really quite easy to trim the fairing with a single cut with a good pair of tin snips.
Hope this helps.

--hawk

[szicree]

Pre-drilled holes? What the heck are those?

Thanks Hawk, I think you've answered all my questions.

Steve

[pierre smith]

Hi Steve,
Just be very careful NOT to get too near the trailing edge of the wing with screws/nut plates. We were more than an inch back from the end of the top skin and the flap leading edge (curved section) interfered with the nut plate and especially the screw. We did not want to make new root fairings, so we ended up cutting a slot in the flap curved leading edge section to allow the screw to travel in. This little 'slot' is only visible when the flaps are extended anyway.
Pierre

[szicree]

Thanks Pierre. I'm sure I would've missed that.

Steve