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RV-7 Construction Log
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Date:  4-11-2016
Number of Hours:  5.60
Manual Reference:  p. 8-11, DWG 26
Brief Description:  Elevator Bellcrank Support and Bellcrank

The next steps in the manual was to drill the F-728A vertical bellcrank support to the F-706 bulkhead, fabricate and install the F-728B reinforcement angle, and permanently install the support to the F-706 bulkhead. For reasons I don't recall, I had already installed the reinforcement angle and attached the support to the bulkhead and bottom skin. All I had left to do was attach the support at the top. To accomplish that, I first primed the faying surface on the F-706 (I had primed the F-728A previously), then dimpled both parts for the specified AN426-4 rivets. The instructions warned that riveting access would be tight, and that CS-4-4 rivets are acceptable. However, my no-hole squeezer yoke did a fine job on the solid rivets.

The next job was to fabricate parts for the F-635 elevator bellcrank and associated parts. The plans and Chapter 4 of the build manual both say the F-635B spacer between the main bellcrank halves is to be fabricated out of flat stock. After spending a half hour or more looking for said stock, I noticed that the spacer is prefabricated with the bellcrank halves. All you have to do is cut them apart and deburr the edges. DUH!

I wasted another hour or so looking for the 3/8 heavy wall tubing stock to make the bearing spacers. Thinking I'd found it, I made two spacers per plan only to find out I'd used 5/16 tubing instead of 3/8. Well, another hour-long search netted the proper material (in the last place I looked). The plans dimension spacers are nearly 1/16 too long for the stack up to fit in the designated space. I suspect that the steel washers were added somewhere back in history and the spacer dimension didn't get updated.

The first round with the proper material failed because I miss-measured the stack up and ended up with about 0.040 side play. On the next round, I got one right, then got too aggressive with the belt sander and ended up short. Fortunately I finally got two good spacers before using up all the material, but just barely.

Rivets Today: 4
Rivets Total: 11632
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This joint will get flush rivets from the front.

This joint will get flush rivets from the front.

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This is how I squared the ends of the bellcrank spacers and ground them to length.

This is how I squared the ends of the bellcrank spacers and ground them to length.

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Took 7 tries to get 2 good ones...

Took 7 tries to get 2 good ones...

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