Flop tube questions

[N546RV]

So today I got to working on the right tank, which is getting a flop tube. Most of this stuff is pretty straightforward, but the plans/instructions are pretty vague about things, and I ended up with a few questions:

Is the bulkhead fitting for the tube OK without some kind of anti-rotation bracket? I know the plans call for safety wiring the tube to the bulkhead fitting to prevent it from detaching, but is there any need for some kind of measure to prevent the bulkhead fitting itself from rotating? Or is the combination of torquing the nut and covering it in sealant enough to keep it in place?

Speaking of the bulkhead fitting - for the regular pickup on the access plate, the plans clearly call for one of those thick washers on the outside of the cover plate, under the nut that holds the fitting in place. There's no such detail view of the bulkhead fitting for the flop tube, but since it passes through thicker material, it doesn't seem like there's sufficient threads on the fitting to use one of those washers here. Besides, it would get in the way of the rivets, I think. But it seems like there should be some kind of washer here...right? Or does the nut butt against the attach angle? Or do I need a different bulkhead fitting?

Finally, there's the trap door. I fabbed it up per the plans, looks nice, etc...but then I put it in place on the rib, and found that the upper hinge half just barely makes it across the stiffening ring in the rib. I figure I can get two rivets on the aft end of the thing, but that's it. So I'm thinking that I'll make a little joint strip out of the same material as the door, and use that to extend the hinge mount forward a bit (see image below). Any reason I shouldn't do this?



Thanks!

[aeroaddict]

I would fab and install a anti-rotation bracket for the flop tube. This will hold the tube in place while you install the nut. The assembly could rotate while you are trying to torque up the nut. Or rotate when installing the fuel lines later in the build.

No washer needed and I believe there is not sufficient threads for a washer as the flop tube installation is in the already very thick wing attach angle.

I also ran into the same flap door issue and just used a home made shim to take up the gap on the third rivet. Remember, the rivets just hold the little door in place. I would even think that two rivets would be fine, but I always try to follow the plans.

[Lemmingman]

Here's how I handled my flapper.