Monthly Archives: February 2015

So many holes…


I didn’t fully appreciate how long the countersinking on the spars would take!  There are SOOOO many holes.  116 nut plate holes for mounting the fuel tanks, nut plate holes for mounting access plates, and 300 skin attach points — for EACH WING.

I first countersank the nut plate holes as called out in the plans.  You are trying to remove just enough material to get a AN426-3 rivet to sit flush.  I checked each countersink as I went along.  It felt like it was going fast, but then I turned around and saw how many holes were left to go!

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Luckily my son came out to help.

He did a great job on the skin counter sinks for the very visible left upper side.

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I made a test dimple in a scrap piece of .032 aluminum to make sure that the skins would eventually sit flush.  You can see it in the close up below.

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After finishing the top left, my son took off (can’t spend too much time with the old man in a cold garage after all!).  So I was on my own to finish the countersinking for the left bottom.  That was it for the day.  No build time on Sunday because I actually went flying instead!

With the left spar fully drilled, I hoped to move on to riveting the nut plates so I could finish Section 13.  I decided that it would be better to finish drilling and countersinking the right spar to keep the wing builds roughly in sync.

I was building on Friday (normally my “honey-do” day since I’m only working 4 days a week as a consultant) because I’m headed off to Houston to visit my brother.  I woke up early with dreams of hitting the shop at 8 and working all day.

Didn’t happen!

My wife woke up and I ended up doing a couple of small honey-do items anyway 🙂

Then I had to mail off a package and fill the minivan with gas before the trip.  The first station was closed, so I went directly to the post office instead.  A huge line for mid-morning Friday!  Then off to an alternate station to fill up (but no left turns allowed to exit).  I finally dragged myself in to the shop only to discover that I left my heat gun at home.

My shop gets really cold.  And it is “power” challenged (one shaky 15 amp circuit shared with the rental house).  And if the power blows, it takes an hour to get it back on again (breaker panel in locked basement only accessible by landlord).  So, I have to baby my compressor to get it started by preheating the block.  So, another 50 minutes was spent heading home to find it and bring it back.

Then my son called to see if I wanted to grab lunch with him between classes.  So we had a quick lunch, but at least I gained another set of hands.  I finally hit the shop around noon.

The j-channel was already set up on the right spar.  It went much faster with a second pair of hands to put the clecos in.  With that done, my son headed back to class and left me alone with my countersinking.  At least that’s all done now.  3 build sessions to take two expensive spars and to transform them into something that looks almost identical to what I started with.  Sigh.  At least next time, I can actually do some riveting (before finishing the final countersinks into the nut plate holes).


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