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Archive for September, 2010

Fitting Skins to the Wing – 4 hrs

September 27, 2010 Leave a comment

Sunday Sept 26, 2010

Today I started fitting the skins on the wings. The first step is to cut the wing walk doublers to size from a larger sheet of .025 aluminum. I was a little concerned about cutting these with the snips because I thought the edge might curl a bit. But I was assured by another builder that it was not a problem so I started cautiously using the straight ahead snips. Sure enough the edge was clean and not significantly curled so it turned out fine, especially since this cut is covered by the top skin and no one will ever see it on the completed airplane.

Next I aligned the doublers to the top skins per the instructions and match drilled all the holes through the doubler using the holes in the skin as a template.

Here you can see the drilling process using clecos right into the top of the work bench to keep everything aligned and flat.

Next I installed the top skins and doublers with clecos. This takes a lot of clecos!

Then I began checking the straightness of the wing using a home made plumb bob on each end. I also made clamps for the aft end of the wing to the stand to lock everything into place. When I checked both ends of the right wing there was about 0.1 inch difference which I was not satisfied with so I rechecked the level on both ends and found some differences. I also found that my Craftsman digital level seems to be about 0.1 degree off at dead level.  I’ll fiddle with this some more before match drilling the skins to the wing skeletons.

For some reason I decided to install the plastic conduit through the previously drilled holes in the right wing ribs. I started at the root and began feeding it through one rib at a time. Don’t follow my example. Turned out it was tough feeding the conduit through the four most inboard ribs because they are close together. It took me over an hour to get the conduit as far as you see it here. And my hands are sore for working it. Next time I’ll start in the middle of the wing and feed it through both directions to the root and the end of the wing.

Categories: Wings

Making Wing Supports – 3 hrs

September 27, 2010 Leave a comment

Saturday Sept 25, 2010

This evening I assembled supports for the mid span of the wings from some all thread, nuts, washers and blocks of wood. After making these parts I used the recommended fishing line stretched from end to end across the main spar to measure the straightness.

With the jacks under the middle of the rear spar it is simply a matter of adjusting the nuts until the main spar does not sag as indicated by the lower row of holes for the top skins.

Here is a shot with both jigs installed and adjusted.

Categories: Wings

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 Ribs to Front Spar, Right Wing – 1 hr

September 24, 2010 Leave a comment

Friday Sept 24, 2010

Work has been overriding airplane building this week so it has been a few days since I had time to work on the wings. But tonight after work Denise helped me rivet the main ribs to the front spar of the right wing. It really helps to have a helper when bucking rivets. We used a straight cup set with a Snap Soc (Denise drove the rivet gun) and I bucked with the tungsten bucking bar. We riveted thirteen ribs to the front spar in a little over an hour and the quality of the rivets is excellent.

Categories: Wing Ribs, Wings

Riveting Rear Spar and Priming – 5 hrs

September 19, 2010 Leave a comment

Sunday Sept 19, 2010

I completed two significant tasks today. First I riveted the rear spar to the main ribs of the left wing skeleton. This was a little awkward to do solo. I never like to buck button head rivets solo because you need to concentrate on keeping the cup set firmly against the rivet head and the bucking bar square to the rivet shank without drifting off all at the same time. If the cup set hops off you can get a nasty “smile” on the rivet head, or worse, on the rib. If the bucking bar drifts off you can get a nasty “cut” across the rivet shank. As a result I had to drill out about five rivets and replace them. It takes a lot of time to carefully drill out and replace rivets.

I started on the third rib from the inboard end because these ribs are very closely spaced and I could move the inner two ribs out of the way to make room for the rivet gun (factory head inside on the thinner material). Here is a shot after shooting the four rivets on rib 3. Notice the inner two ribs shifted over an inch or so.

Then I went to rib 2 and shot it’s rivets with rib 1 moved over. Then I shot the rivets on rib 1. Then I started at rib 4 and progressed all the way out to rib 14. This was all done on the work bench as you can see here.

Then Denise and I put the wing back onto the assembly jig because the next step will be to install the upper skins.

I also applied a coat of primer to all fourteen of the main ribs for the right wing (the ones I preped yesterday. The process is boring but here is a photo of the completed primer job with ribs laid out to cure over night. The Stewart Systems primer gets pretty durable after a day or two.

Categories: Wing Ribs, Wings

Preping Right Wing Ribs for Priming – 4 hrs

September 18, 2010 Leave a comment

Saturday Sept 18, 2010

This morning I began final preparations of the main ribs for the right wing for priming. This consisted of checking the squareness of all flanges and adjusting where necessary, checking straightness and tweaking the fluting where necessary, and scrubbing all surfaces with a scotch-brite pad to remove the shine.

I finished nine ribs before I left to go fly a solo cross country for my pilots certificate. Just as well because I needed to pick up some primer, safety wire, and scotch-brite pads at Aircraft Spruce anyway. When I got back in the afternoon I finished the remaining five ribs and I washed them all with Simple Green then rinsed well.

No pictures. Too boring to photograph.

Categories: Wing Ribs, Wings

Riveting Ribs to Front Spar – Left Wing 1.5 hrs

September 17, 2010 Leave a comment

Friday Sept 17, 2010

Tonight I riveted the main wing ribs to the front Spar for the left wing. I did this solo using Snap Socs on a straight set with my tungsten bucking bar. I started slowly but speed picked up as I progressed. All but the most outboard rib gets riveted to the spar at this stage. The outboard rib will be riveted later according to the instructions. Here is a photo.

Categories: Wing Ribs, Wings

Riveted First Rib to Left Main Spar – 1 hr

September 13, 2010 Leave a comment

Monday Sept 13, 2010

I didn’t have a lot of time in the shop tonight but even a little progress is OK sometimes. I received my order from Avery Tools today and it contained a pitot mast, pitot static installation kit, AOA line installation kit, and a bag of 10 Snap Socs. Here is what came in the box.

What’s weird is I order red 1/8 Snap Socs but Avery shipped green 5/32 Snap Socs. I wanted the 1/8 version to rivet the main ribs to the spars. I’ll call them tomorrow to find out what happened. In the mean time I wanted to proceed with riveting the main ribs to the front spar. I learned from other builders to start on the third rib from the inboard end and work toward the fuselage because the ribs are close together and face inward. You can easily bend the ribs out of the way of the rivet gun with the manufactured heads on the rib side. Then go back to rib four and work outboard.

So I shot the first set of rivets on rib 3 using a green Snap Soc. It may not fit the rivet perfectly but it seemed to help reduce the bounce of the rivet gun and I successfully drove all five rivets without a problem.

With the little extra time I had I checked the rest of the main ribs and tweaked straightness and flange perpendicularity in preparation for riveting them on in the next day or two (work schedule permitting).

Categories: Wing Ribs, Wings

Priming Ribs, Left Wing – 5 hr

September 12, 2010 Leave a comment

Sunday Sept 12, 2010

This morning I set up an improvised spray both in the garage using plastic drop cloth. Not the best method but I was able to spray the 14 main ribs for the left wing. I had room for eight ribs at a time so I had to keep shuffling ribs around to get through them all. Here is a photo of eight right after spraying the top surface. I used Stewart Systems Ekoprime White. It goes on fast, dries pretty fast and seems to be very tough after drying.

Here are the 14 ribs after priming. They dried in the sun for a half hour or so before I brought them back into the garage. I am almost out of EkoPrime so I’ll have to order more from Stewart Systems or pick it up at Aircraft Spruce before I prime the right wing ribs.

Here you can see that I remounted the outboard rib with cleco as I set up for riveting. I realized that it might be easier to match drill the leading edge ribs before I rivet the main ribs in place so I finished fluting these five ribs and match drill them to the main spar. I ordered some Snap Socs from Avery Tool but they have not arrived yet. I want to use those to rivet the ribs to the spars so I will hold off until they arrive.

Categories: Wing Ribs, Wings

Preparing to Prime – 8 hrs

September 11, 2010 Leave a comment

Saturday Sept 11, 2010

I got some good quality time on the wings today. First order of business was to finish drilling holes for the electrical conduit and snap bushings in the wing ribs. Here is a photo of the left wing skeleton showing the 3/4 inch holes for the conduit and the 1/2 inch holes near the front spar for snap bushings. I may run power for the wing tip strobes there to isolate it from the other wires like the roll servo.

Here is a similar view looking down the right wing. These holes are the result of quite a few holes of work removing ribs, locating the holes, drilling 1/4 inch pilot holes, then drilling to size with a unibit, deburring and reinstalling. The results are the reward.

The next step was to match drill the spar to rib holes. I started by drilling all the main spar to rib holes with the wing on the assembly stand, then I put the wing on the work bench to drill the rear spar holes. Here is the left wing after drilling through the spar holes into the ribs.

Here is the right wing set to drill through the rear spar.

Then I disassembled the left wing and spent several holes preping all the  ribs for priming. This included buffing up all surfaces of the ribs with scotch-brite, checking for burrs and rough edges, and finally washing all the ribs with Simple Green and water. After a good rinse, the left wing ribs were laid out to dry.

I plan to prime these tomorrow. By the way, Harbor Freight Tools has a great deal on latex and nitrile gloves; a box of 100 for $6. That is way cheaper than Home Depot. They come in handy when washing ribs and priming. It is important not to handle the parts with bare hands after they are washed and before priming.

Categories: Wing Ribs, Wings