Good day, today I’m starting to work on the flop tube fuel pick-up installation, and in particular the anti-hang up guide over the root rib access panel. This is another one of those areas were the HRII Sport Wing plans are silent and the RV-4 plans are very basic in their description. Reviewing many other builder logs, there are a varied number of ways a builder can approach how to do this. The method I chose to go with is to build the anti-hang up guide over the access panel in a fashion where it’s attached to the panel to facilitate removal of the access panel.
Below are the applicable sections of the RV-4 drawings which pertain to the flop tube installation and anti-hang up guides.
I also quickly drilled the fuel pick-up line hole in the right tank access panel, as it will be fitted with the standard fixed pick-up line. I made a new solid access panel here because I’m using the capacitance fuel sender system, and therefore can’t use the pre-drilled T-708 access panel. But it did work out great as a drilling template for the line and anti-rotation bracket locations.
Anti-Hang Up Guide
Moving on to building the anti-hang up guides, in the picture below, you can see that I was so into what I was doing that I laid out the bracket location on both the left and right root ribs, when I only need it on the left side where the flop tube is located. In the picture below, you can also see the fixed fuel line pick up and anti-rotation brackets are now located in place.
I constructed the anti-hang up bracket from some half inch strips. One of which was the length of basically the from the upper side of the rib, down to the bottom of the access panel opening. Then I constructed 2 mounting brackets in a ‘Z’ pattern, which will be riveted to the access panel itself.
Here’s a view of the bracket viewed directly top down.
On the lower side of the access panel, I fabricated a ‘C’ shaped bracket which is attached to the reinforcement ring. This bracket extends down until it almost makes contact with the bottom of the fuel tank skin.
That’s all for today folks! Please comment. I love to hear from my readers. Thanks again for coming along for this ride, you make my work worthwhile.
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