Sunday, July 7, 2019

Finished the crotch strap brackets - 6.5 hours

Another big day on the build today. I managed to complete the co-pilot crotch strap bracket in short order. Next I was ready to drill the forward most brackets. I ran over to Home Depot in the morning and picked up some 1/8” aluminum flat bar to use as spacers.


Once I had the spacers cut, I was then able to cleco the entire assembly together. I double checked the fit and was really happy with how everything laid out.

Next, I disassembled one side for the F-716 ribs allowing me to match drill into the other F-716 rib. This process worked extremely well, and disputed using all of my special cleco’s it was fairly quick to complete both the pilot and co-pilot brackets.


Next I was ready to drill the anchor bolt hole for the crotch strap itself. The crow harness has a slightly longer mounting hardware than the vans so it was obvious I wouldn’t be able to use the stock pilot hole. It places the belt return too high and out of the relief hole, so I will need to move it down.


 Taking a hint from Mike Bullock’s RV build page, I moved the hole down just slightly over 1/2” (0.510” to be exact). I then drilled a pilot hole to #30 in the aft bracket.

I drilled a #30 hole in the center of the aluminum spacer. I then cleco’d the aft bracket to the spacer, and reassembled. Once I had everything clamped, aligned. I removed the #30 cleco and match drilled the forward bracket to #30. I disassembled and I had perfect setup to open the #30 holes for the AN5 bolt.

One small item that I needed to do was to trim the innermost seat belt mounting brackets to clear the F-916 spacers. I had trimmed them originally, but they needed a tad bit more.




I was going to turn in for the night, but I decided to match drill the AN3 bolts that connect the main spar to the F-716 ribs. That went very well, but unfortunately one of the holes was set a bit to much inboard in relation to the line of rivets and the edge distance doesn’t look good. A couple of other holes aren't great, but this one is the worst. 

On further inspection, it would appear that the factory drilled holes are a bit out of alignment. These holes are already drilled, I just needed to match drill them.



I’ll send an email off to Van’s to see what they suggest. Maybe it will be ok given the location and circumstance. I looked at a few other build websites and I notice similarities in other projects.

UPDATE July 16-19 - I didn't get an email back from Van's so after a week of waiting I called in to builders assistance. Support reviewed the pictures and said that this was an easy fix. They recommend I build a doubler with the same thickness of the flange and large enough to catch at least the two adjacent rivets below and make the doubler wide enough to provide proper edge distance for the AN3 bolt.