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Countersinking Right Main Spar for Skins – 3 hrs

December 30, 2010 Leave a comment

Thursday Dec 30, 2010

Today I finished countersinking the right wing main spar for all the skin dimples. This is tedious and just takes time. Here is another shot of the sea of holes that must be machine countersunk. This was before I put a dab of primer on each countersink with a Q-tip.

Way too many holes!

This is a shot of one of the “orphan rivets”, right in the middle of the picture. I call them that because the plans don’t address them. There are about six holes in each side of the spar that align with the ribs but they will be covered by the tank skins. You have to rivet these now before installing the skins or never.

Orphan rivets

I came up with an easy way to clean ProSeal off of clecos. Rather than soak each one and wipe the ProSeal off with a paper towel I put them into a large mason jar and add an inch or so of MEK or Toluene and shake it up for a while. The agitation washes the sealant off of the clecos and it settles to the bottom after a while. Works pretty good.

Cleco washing machine

I was craving a little change of pace after working on the skins and tanks for so long so I decided to measure and cut the aileron pushrods to length. These are cut out of a 12 foot long piece of raw stock. I found that the fittings are to large in diameter to slip into the ends of the tube easily. I’ll have to research what to do about that.

Aileron push rod tubes

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Categories: Main Spars, Pushrods, Wings

Completed Left Leading Edge – 8 hrs

December 28, 2010 Leave a comment

Tuesday Dec 28, 2010

It’s great having time over the Christmas break to put into the airplane. I feel like I am making up for lost time for all those weeks when employment kept me out of the shop for days.

This morning Denise helped me with the last 60 or so rivets on the left leading edge. She is all done now with the exception of putting the screws in to attach the access cover. I’ll do that after it’s mounted on the wing. It’s amazing how light this section of the airplane really is.

Left Leading Edge done!

Next I checked on the state of sealant cure on the right fuel tank. It’s looking good. I went ahead and bent the vent line to the high point of the tank. I plan to install the baffle tomorrow.

Vent line bent to the high point

In preparation for riveting on the wing skins I machine countersunk the holes in the main spar on the left wing. To do this I had to remove the skins. But first I checked the straightness of the wing using the plumb bobs on each end. Still looks good. Apparently nothing has shifted over the last few months.

Turns out there are a lot of #40 holes to countersink. I counted about 340 on the left main spar alone. Here is a partial shot. It took quite a while to machine these. Afterward I put a dab of primer on each countersink using a Q-tip.

Some of the many holes countersunk

While I had the left upper skins off I went ahead and deburred the edges. My technique is to first use a file to knock off the big burrs and punch artifacts. Then I use a scotch-brite wheel in my die grinder to smooth out the edges. Then finally I use a scotch-brite pad by hand to smooth the edges more. When done the edges are silky smooth. I also took the vinyl off the inside surface completely and along the rivet lines on the outside. This stuff is not hard, it just takes time.

Deburring and de-vinyling

I started working on the scarf joint on the left inboard skin. I measured 3 inches along each edge and used a file and a sanding block to take material off. After about 15 minutes I had taken maybe 0.005 off of the surface. At least I am not moving too aggressively.

Starting the work the scarf joint

I took some time to clean up the garage a bit and mounted the leading edge and skins back on the wing. The leading edge might be on to stay. The skins will have to come off again to complete the scarf joints and dimple. I will also probably spray on some primer along the rib lines.

Left Leading Edge ready to rivet

Riveting Rear Spar to Right Wing – 1.5 hrs

September 25, 2010 Leave a comment

Saturday Sept 25, 2010

I had to go in to work again today but I had some time in the garage between about 6 AM and 7:30 AM so I riveted the rear spar to the ribs of the right wing. This time I used the squeezer with a longeron yoke and it was much easier than when I bucked them on the left wing. When I initially looked at it on the left wing I thought the longeron yoke wouldn’t reach. This is one of those cases where the instructions don’t tell you how to install the rivets and I failed to research it on the web enough to realize that I could use the squeezer.  Turns out the longeron yoke works fine in this case. Lesson: Research other builders experiences on the web at least a few steps ahead before executing. Here is a photo of the completed rivet job on the right rear spar.

Categories: Main Spars, Wing Ribs, Wings

Riveting The Rear Spars – 3.5 hrs

August 28, 2010 Leave a comment

Saturday Aug 28, 2010

I was looking at one of the web sites of a builder last night and saw that he dimpled the holes on the rear spar flange that mate with the W-707E and W-707F doublers before assembly. I could not find any instruction in the plans to do this but I didn’t see any reference as to how or when to dimple them later either. I searched the Vans Air Force forums and found that this question has come up before and one post even quoted a response from Vans Builder Assistance. According to Vans you can drill and dimple before riveting these parts together or you can machine countersink just the spar flange later. The forums really are a great asset to a builder.

You can see the seven holes adjacent to the W-707E flange below. These mate to the top skin of  the wing.

I decided to try drilling out one hole and dimpling it. When I did I found that the W-707F doubler is very difficult to dimple without distorting it. The holes are just too close to the web. So I decided that machine countersinking would be easier and less likely to damage the parts and I can do that later after fitting the skins. So I left the rest of the holes undrilled and undimpled. I hope I will be happy with that decision later.

I cleco’d all the rear spar parts together and put tape on all the holes that should not be riveted now.

Then I started riveting. All these rivets could be squeezed with the 3-inch yoke on my pneumatic squeezer. Here are the finished parts with rivets in the required locations. I put the factory heads on the side with the thinner material where applicable. In the case of the W-707E/F doublers both parts are the same thickness.

Rear spars done!

Categories: Main Spars, Wings

Priming Rear Spar Parts – 4 hrs

August 27, 2010 Leave a comment

Friday Aug 27, 2010

Today was the day to prime the rear spar parts. The basic steps are:

1) Scotchbrite scrub W-707A rear spars for priming

2) Scotchbrite scrub remaining rear spar parts for priming

3) Clean rear spar parts for priming

4) Prime rear spar parts

There is a lot of surface area on the rear spar parts to scotchbrite scrub so I tried putting a strip of scotchbrite on my orbital sander. It did a great job of covering the flat areas of the spar channel. You can see in this picture the area on the right that was scrubbed versus the shiny area on the left. This will help cut down on the time it takes to prep these large parts.

The next step after scrubbing all the parts was to wash them and scrub again lightly with Simple Green. That cuts the grease and gives a water break free surface. Then I set up the spray gun and applied a few light coats of Stewart Systems white water-based primer. Here is one set of parts for one rear spar primed.

After a couple of hours the parts were assembled with clecos in preparation for riveting tomorrow.

Categories: Main Spars, Wings

Finished Fab Steps on Rear Spars – 2.5 hrs

August 26, 2010 Leave a comment

Thursday Aug 26, 2010

Build steps completed tonight were:

1)  Mark rear spar parts with location and orientation for later reassembly

2) Mark and cut out holes for the aileron pushrods. Deburr Edges

3) Drill holes in the W-707A upper flange along length of W-707G and dimple

4) Machine counter sink holes in W-707F for flush rivets

In the picture below you can see the cutout pattern marked on the W-707E doubler and I have roughed out the two major radii with a unibit. The finish work was done with a dremel (rotary) tool and a small sanding drum attachment.

Here you can see the final cutouts which match the cutouts in the W-707A quire nicely.

Then I drilled out and dimpled the holes in the W-707A flange next to where the W-707G will be installed because you can’t get a dimpler in there after the W-707G is installed.

Here are the machine countersinks in the W-707F doublers for rivets that will be underneath the aileron brackets.

All done fabricating the parts I cleco’d each set together and stood the rer spars next to their front spar companions.

Categories: Main Spars, Wings

Match Drilling the Rear Spar Parts – 1.5 hrs

August 25, 2010 Leave a comment

Wednesday Aug 25, 2010

First step tonight was to deburr the edges of the right rear spar. Like the left spar, it was time consuming taking almost 45 minutes to complete. Then I cleco’d all the parts of the right rear spar assembly together per the instructions and matched drilled all the mating holes. I also match drilled the left rear spar assembly I cleco’d together last night. Here are the inboard ends.

Here are the holes for the W-707E doublers. I still need to cut out the oval holes for the aileron push rods.

Here are the holes for the W-707F doublers.

Categories: Main Spars, Wings