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David Paule 05-09-2013 10:29 AM

Main Ribs To The Front Spar
Starting with the right wing and using some bushings, I pilot-drilled the main ribs to the front spar. The first pass was through the web of the spar. Once that was done, I removed the ribs, drilled them to #30, and clecoed them to the spar.

With all of them clecoed, I used more bushings to pilot-drill for the 3/16 inch holes through the caps. Then I disassembled the ribs and drilled them out to the final size.

The next step was to remove all the ribs for deburring.

The left wing, shown here, is now ready for the first pass of pilot holes.

If you look closely you'll see that the ribs have all been drilled for the plastic bushings for the lights and stall warner and pitot lines. It's pretty easy to do that when the ribs are off the spars, and harder when they're on. You don't need to know the specific brands and models of these things yet, just roughly how many wires and hoses to allow for. The wires, etc., will go in before skinning the wings.

The holes in the rear spar to the ribs are all drilled but haven't been dimpled yet. I learned that my pneumatic squeezer will indeed dimple the .040 rear spar. The blue parts in the background are the flap brace and aileron fairing. The aileron fairing is the W-724 substitute that Randy Lervold recommended. They're here so that I could see which holes needed dimpling. At this stage of the game, I'm not convinced that the W-724 is a significant time-changer for a standard-build kit. But on its outboard end, it's already trimmed correctly for the aileron hinge fittings, and that's a plus, especially since the plans don't mention that at all.

The drill bushings were straight from the local hardware store. These are simple brass tubes that nest in one another. The one on the left was used for the #30 web holes, and the set of longer ones was used for the 3/16 inch holes in the spar caps. The smallest tube takes a 3/12 inch bit, shown, but not a #40 bit.

These have done a good job of protecting the front spar while drilling all those holes.

I keep them in a small parts ziplock bag in my drill drawer so I don't lose them. I hate losing things like that and I'm very good at it.


David Paule 06-12-2013 11:35 AM

Wings On Jig
Right now the wings are on the jig, and most of the nose ribs are mounted. Except for the tanks, there's one rib to go on either side.

The inboard-most nose ribs are now being mounted.

And yes, the garage does have windows on three sides.


David-aviator 06-16-2013 07:27 AM

Your garage is a real airplane factory, David. The process is different than assembling a pre punched kit, it is a genuine build and looks great.

Long live the -3!!

David Paule 06-27-2013 09:22 PM

Caught Me By Surprise
I was following the manual, kind of chugging quietly along, and suddenly came upon a section called "Fitting The Wing Skins." And the next thing I needed wasn't some small piece of 3/4 angle, it was the one-piece top main wing skins.

So out to the hangar I went, and back home I drove, with two skins and the walkway doubler piece in the truck. They are now in the shop and I'm wondering how on earth I'll manage them all by myself.

That wing crate still has a number of things in it that I haven't touched yet, but it's definitely looking more empty than it had been.


rockwoodrv9 06-27-2013 09:36 PM

After working with all the small parts, it must be strange getting to the big stuff! Have fun.

wirejock 06-30-2013 09:08 AM

I'll help any time. Fri-Sun. Call me if you need an extra pair of hands.

David Paule 06-30-2013 10:20 AM

RV-3B: More Think, Less Build
Thanks - gotta figure out just how to do this first. If the wing jig permitted having the wings horizontal, it would be a cinch, but it doesn't.

Looks like the first step will be to drill the skin holes that mate to the spar flange. I can drill the skin on the bench and use that to drill the flange. Then the rest should be straight-forward once I decide how to support the skin on the frame before drilling anything. I want to think the process through before committing to anything.

I made a simple edge-drilling jig. It's two pieces of 4130 plate, .093 thick and about 1.5" x 3" that make up the "bread" of the sandwich. The "filling" is a strip of .040 aluminum about 3" x 1/2" wide. I riveted these together with the aluminum on one side. Most of the space between the steel parts is empty. I drilled a #40 hole through both steel pieces that's 1/4" from the inside edge of the aluminum strip.

This gadget slips over the skin and lets me drill a hole a constant 1/4" distance from the edge. Or will once I start using it.

I used 4130 because I had the scrap on hand. The .040 aluminum is thick enough that it lets me keep the blue vinyl on the skin while I"m drilling. Making tools is a helpful way to think about how to build the airplane, and this tool is a general-purpose one.

And yes.... I acknowledge that my Whitney punch has a stop that would let me set this distance and simply punch these holes. I remembered that after I'd built this jig, sigh. I'll play with both and then decide which I want to use.


longranger 06-30-2013 04:38 PM

If you really want to work your wings horizontal, consider this type of fixture. Just a large bolt welded to heavy angle through a hole in the vertical square tubing. Each is easily leveled independently to ensure no twist in the spar:

Here they are in action. Saved me from having to lay on the floor to rivet the skin to the rear spar:

David Paule 07-23-2013 09:33 PM

Working away on the wing skins. The top main skins are now drilled to the wing and have been removed so that I could drill the bottom skins to the wing. Between skins, I double-checked the twist and to the limits of my measuring tools, it's still zero.

I made a dumb goof on the bottom skins and you've got to remember that this is an RV-3B and it's not pre-punched. I merrily went along drilling the skins and the spar flange, figuring I'd sort out the inspection hole covers later.


The inspection hole covers have dedicated fastener holes in the spar flange and now I've got rivet holes there instead. I'll have to sort that out and figure out how to do it. In the meantime, I've been making the inspection hole doublers and that's reasonably straightforward. The photo shows the ones for the right wing. At the top is the pattern for the outboard left wing. It has a strange ear on one side because it'll also double the pitot tube hole in the skin.

The outboard bottom skin is long enough for a double row of rivets at the splice. I had originally thought to use one row with 5/8" spacing (as shown in the plans) as it would be slightly lighter, and then realized that the double row and wider spacing would be smoother. Drag versus weight? In this case drag won the day.


David Paule 08-12-2013 08:29 PM

Now Leading...
Well, now I'm fitting the leading edges, anyway.

The main skins are drilled and clecoed, but not dimpled. The top and bottom skins are clecoed to the wing frame right now, and the leading edge skins have been drilled and clecoed to the top of the main spar.

I've drilled the top flanges of the nose ribs and plan to back-drill the leading edge skin to these flanges once I've got the skins pressed down to the nose ribs.


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