More Crow crotch strap installation documentation
I recently decided to add the crotch strap to my RV-9A project. I wanted to document how I did it for others.
So, the crotch strap attachment that Crow supplies has holes in them that are much larger than the 5/16" bolts supplied with the Van's crotch bracket install kit.
The attachment on the left is the one that comes with the crotch strap. I had Crow send me a couple of the bigger attachments like the center one. I then drilled an additional 5/16" hole in it like the third picture. It was very easy to drill through it on my drill press. Step up the bits slowly as somebody mentioned in this post and use an ample amount of lube.
For spacing, I just dropped a few of the attachments down between the brackets and drilled:
Here is how the strap fits:
What I didn't like was how the strap lays against the edge of the bracket cut out like in this picture:
Everything would be fine as long as the strap was being used. If it wasn't used, it would just lie there and rub due to aircraft vibrations. Yea, I knocked off the sharp edge of the bracket per the instructions but I still wasn't confortable with it. I even sanded them smoother than these pictures show.
I thought initially that I would redrill a couple of attachments with the hole further down but then realized that even if I had done that, the attachment could get clocked a bit causing the same situation.
My fix was simply to put a couple of strips of black electrical tape over the formerly sharp edge. It worked great.
So there you have it. You might want to get a total of 6 of these longer brackets from Crow...two for the crotch straps and four for the lap belts. By the way, the holes are too big on the lap attachments as well but as was described on this forum, simply squeezing a couple of AN washers into the large hole on the brackets quickly fixes this problem.
The Crow folks are great!