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Started work on the rear spar and ribs

Last night I started work on the rear spar. To make some room, Bill and I finished my wing stands and clamped the main spars onto it. Over the coming weeks, the wings will be constructed on this stand. I can’t wait. It will start looking like a real plane!

After cleaning the bench I picked out the parts for both rear spars and laid them out. I removed the vinyl from all the parts except the flap reinforcement doubler and labelled them with my Sharpie.

The plans called for the rear spars to be deburred first. Bill showed me an absolutely fantastic way of breaking the edges. We clamped the spars to the bench and used a file by rubbing it along it’s long axis up and down the length of the spar. We did a couple of passes with the file perpendicular to the spar flange to remove the tool marks. Once the surface was smooth, I repeated this on both sides of the flange but tilting the file on a 45 degree angle. Once the edges were broken we wrapped from 400 grit sand paper around the file and repeated on edge side of the flange. The result was a flange edge that felt like glass. Sooooooo smooth and it was also very quick! Sure beats using my micro-files!.

I did however get the micr-files out to break the short edges and around the flange radii as the big file was a bit too unwieldy here. I then used my Scotchbrite wheel to round the corners and break the edges on the doubler plates.

It was getting late at this stage so I decided to finish off by marking out the areas I need to trim from the spar doubler forks. The drawings have a full scale detail of the areas to be trimmed and I used this as a template to mark my parts. I checked with my rule that the drawing is accurate.

This afternoon Bill and I managed to get back into the shed again. We decided that we would do a job that would benefit the most using 2 people. I though debarring the wing ribs might be a good idea as other builder’s report this takes a long time. So we set up a bit of a production line and got to work. I picked out all the ribs, removed the sticky labels and marked them all with my Sharpie.

I started by drawing a file along the rib flanges to remove the tool marks. I then broke all the outside edges of the the flanges on my Scotchbrite wheel.

For a time the Chief Filer made an appearance and decided to give me a hand filing a few ribs. As always, his work was first class. Thanks Damon!

The next step in the production line was Bill sanding the inside edges of the rib flanges to break them.

When I finished filing all the ribs, I then moved onto deburring the lightening holes. I used my deburring scraper tool to do this. SOme builders use a small Scotchbrite wheel on a die grinder but I wasn’t confident using this tool. It’s too easy to slip and remove a lot more metal than intended.

Once bill finished sanding all the rib flanges, he started sanding all the lightening holes. Here is a lovely shot of the moment I told him he had more sanding to do. Thanks Bill! 🙂

Once I finished deburring all the lightening holes, I started work on breaking the edges in all the little nooks and crannies that the sand paper couldn’t quite get in to. The nose ribs in particular were painful due to their many notches.

We didn’t quite finish doing all the ribs tonight but I think we made great progress. There are about 6 or so ribs that Bill needs to sand the lightening holes on. Here are the ribs that are waiting for me to debur all the fiddly bits.

Fortunately most of the nose ribs have been completed. Here is a shot of the ones we have finished.

Since Bill and I were working in parallel tonight, I’ve accounted for both of our man-hours in capturing the build hours completed. Build time over the past 2 days – 18 hours.


About gstrack

Husband and father of 2. Control & Instrumentation Engineer. Flying nut. Gadget geek.


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