March 4, 2007 - Countersinking Mania
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It was too windy to go flying this Sunday, but I had a productive day
prepping the canopy frame and skin for riveting. I wasn't sure if I
should dimple or countersink the side skirts. The canopy frame side
wildments seemed fairly thick so I tried countersinking one hole. It
worked fine. So I countersunk the two lower rows on the side
weldments. |
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Then I dimpled the side skirts, the lower two rows to #40, and the top
row for a #6 screw.
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You don't believe me? Here's a close-up/ |
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Next I countersunk the canopy frame itself. The canopy frame was
thick enough to countersink, but not thick enough to prevent chattering
by the countersink bit. I solved that by using a little bit of
angle -- seen sitting on the top of a rib -- which I would hold
underneath the hole for backing.
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| I countersunk the canopy frame
until about 1PM, when I drove out to Essex Skypark to do a little
maintenance on the Citabria. It was cold and windy and the skypark was
deserted. Here the Citabria sits forlornly, wanting to fly. I
recharged the left brake. |
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| The skypark wasn't quite deserted.
This is Tiger, the airport cat. |
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Too windy to fly, too cold to want to. No place to go,
anyways. I need to live in one of those airport
communities in Florida! |
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Upon returning home, it was back to work building an airplane. The
canopy skin "ears" need trimming -- indicated by the purple line -- so
they will be aligned horizontally with the side skirts.
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I trimmed the canopy skin ears, deburred all the holes and dimpled the #40
holes. I couldn't reach a few of them with the Main Squeeze, so
Lynnette helped me dimple them with the C-frame. It's been awhile
since I've done this type of work. It was fun. |
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I clecoed the canopy skin back on. Notice the gap between the
canopy skin and the forward skin. This is common, I understand.
What I'll do is put a shim under the forward skin so it is the same
level as the canopy skin.
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| The right side has a gap too, but
not as bad as the left. |
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| I had wondered how to handle the
rear row of holes on the canopy skin, which are #30 and are filled with
flush pop-rivets. Dimple or countersink? There is just an
aluminum tube underneath. Dimpling the skin and countersinking the
tube didn't seem like it would work. I did a search on the Vans Air
Force forums and the answer was to countersink the canopy skin and
underlying tube simultaneously. So that's what I did. It should
work fine. |
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