Got both leading edges clecoed together over the last week. It’s kinda nice to see some good visual progress with not a lot of work.

Left leading edge clecoed

I spent a little extra time making sure that the ribs were set correctly. If they aren’t fitting as snugly as possible into the leading egde skin, the ribs’ rear flanges may push the leading edge away from the spar, resulting in a gap between the leading edge skin and main skins. A little effort pulling rivet holes into alignment with a 3/32″ punch before clecoing will pay dividends later when fitting the leading edge to the spar.

Having mentioned that, I couldn’t eliminate the gap completely on the right spar but it’s reduced enough so that skin expansion during riveting should close the gap almost completely.

The next step was fitting the leading edges’ inboard ribs and tank joint plates. I discovered that the joint plate stock material Van’s shipped was a half-inch too short…d’oh! Had to wait a bit while (free) replacements were shipped.

Both leading edges mounted

With the joint plates mounted and leading edges drilled, it’s on to the fuel tanks.

With the pitot mast installed, I went back to the right wing and began match-drilling skins after double-checking the wing box for twist and sag.

There isn’t too much to tell about this process – it’s pretty much the same as the left wing – with the exception of a couple of skin-to-rib holes that I couldn’t line up no matter how I clecoed the skins to the wing box. I tried adjusting the flutes around these holes, no luck there either. The problem holes are circled in this picture.

Misaligned skin holes

Not wanting to drill the holes with this misalignment, I consulted Van’s and my tech counselor. They both agreed that an acceptable procedure would be to drill the holes, then fabricate a dimpled doubler plate that will be held in place by the wing-to-rib rivet. Sounds good to me.

Had a tech counselor visit today from Jon Ross – his beautiful RV-8 is featured in the April ’06 RV of the month in Van’s calendar (my friend and fellow FTE Mike is in the back seat). Also visiting was future RV builder Rich Prignano. Jon looked at progress so far on the tail and wings. It’s nice to have a TC again…thanks Jon!

I finished match-drilling the left wing skins over the last week. I ran out of #40 clecos and was delayed a bit while some new ones arrived from Avery. I didn’t realize how crappy my old ClekoLok clecos were until I bought the WedgeLok clecos that Avery sells…quite an improvement.

While the left wing box was still together, I installed the SafeAir pitot mast. This is a relatively easy process if you take your time when trimming the hole in the skin that will accept the mast.

The first step is placing the mounting template on the lower skin, just outboard of the most outboard inspection hole. One thing to be aware of here is that the recommended mast location is right next to a rib. After discussing the mounting process with John Sannizzaro, who turned me on to the SafeAir mast, I moved it outboard one rivet to provide some more room for riveting and pitot plumbing. After the template was in place, I traced the outline of the mast hole onto the skin and used a unibit to drill some starter holes inside the outline Here’s the template in place – sorry for the crappy picture, but you get the idea.

Pitot mast template in place

Enlarging and shaping the hole took some time and patience; I started with a side-cutting bit in the Dremel, and finished up with a fine needle file. After the hole was done I fitted the mast inside, marked the forward rivet holes, then removed it and final-drilled the holes to #40.

Pitot mast template in place

With the forward holes clecoed in place, I marked and drilled the rear rivet holes per the directions. Here’s the end result…the installation looks great!

Pitot mast template in place

When will this project be done? When pigs fly!

Flying pig at CVG

Not much progress over the last week, I was only able to get the left wing’s top skins match-drilled and the bottom skins clecoed in place. One thing to look out for here is match-drilling the tabs on each rib that fit under the spar flanges, since they can easily be misaligned even though the main part of the rib is clecoed to the skin. Look at the hole alignment before you drill, and adjust as necessary.

Before match-drilling the left wing skins, I decided to double-check the spar for any twist. I had previously used the SmartLevel to adjust both ends, but I decided to double-check them using Vans’ recommended method – measuring the distance from plumb-bob lines hung from clecos on the spar, to the top edge of the rear spar. The picture below shows the setup.

Checking the wing for twist

Turns out that I didn’t need to be concerned….the measured distances were within 1/32″ of each other. I guess I can live with that.

Getting both wings in the jig was a big hurdle. Now it’s time to start working on the skins, in this case trimming and match-drilling the wing-walk doublers.

The instructions are confusing in this area; they imply that the wing-walk doubler extends an inch past the rear spar. But that’s incompatible with the doubler dimensions as specified in the plans. A doubler fabricated per the plans and positioned the correct distance from the front spar isn’t long enough to overhang the rear spar by an inch. Other builders have had the same problem; some followed the dimensions in the plans, others altered the doubler to comply with the instructions. Also, some folks who had a 1″ overhang eventually had problems with the doubler getting bent down and interfering with flap retraction – not something I’d like to have happen.

Based on my observations of the wing walk structure, and some information I got from the VAF website, I chose to follow the plans dimensions rather than comply explicitly with the instructions. That results in a doubler that overhangs the rear spar by about 4/32-5/32″.

Match-drilling the wing walk

I was on a roll, so I pulled out the top left wing skins and clecoed them on. No problems here, and big visual progress to boot!

Match-drilling the wing walk

John Sannizzaro came up over the weekend and we knocked out the right wing box. A couple of days later I put the wing in the jig.

Both wings jigged

Next step…leveling the right spar’s ends. Gotta love that SmartLevel and those adjustable support arms! I also double-checked the left spar’s alignment.

SmartLevel on right wing spar

Yesterday I finally came up with a (relatively) inexpensive way to jack up the wing center per the plans. I used some spare threaded rod, Al angle and 2x4s to make these little adjustable supports.

Wing center support

The only feature that isn’t apparent in that picture is the flat surface on top. It’s just a piece of plywood left over from a wing crate, with a nut attached to the bottom with JB Weld. I didn’t want to clamp anything to the spar center lest it be damaged if the support was disturbed or kicked out of place.

With the support in place, all that was left was to use it to remove any sag from the wing box. I didn’t have a plumb-bob or fishing line, but I did have a spiffy new laser level I found on sale at Sears. So in an awesome display of obsessive over-engineering, I used the laser level to get the wing box adjusted and sag-free.

Left wing laser-leveled

The picture is a little dark, but you can see the laser line illuminating a row of rivet holes on the spar. I’ll definitely use the approved solution (fishing line and plumb-bob) to check twist before the skins go on, but the laser works well. And that threaded-rod support made it wicked easy to adjust the spar.