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fuel line from flop tube tank

SgtZim

Well Known Member
Anyone have a good tip on making this bend? From the tank fitting - turn 90 within 1.5" to go through the hole in the tank fitting. My flaring tool needs 3/4" to grip the tube + the fitting sleeve takes another 1/4", then the bending tool has a 1" radius = 2" min to turn the line 90 deg. If I could tighten that up 1/4" I'd be good. Thinking of just adding a 90 deg fitting, but I haven't measured how much shorter that will be after all the connections are made.
 
First use bender. Fill with sand then work the bend tighter by hand or with padded boxed end wrenches. Cut to length last. This worked for me.
 
My flaring tool needs 3/4" to grip the tube + the fitting sleeve takes another 1/4", then the bending tool has a 1" radius = 2" min to turn the line 90 deg.

Do the flare first. Then do the bend with the sleeve already installed on the line.
 
And DON'T do something dumb like this;

IMG_1148 by Ed Fleming, on Flickr

Yes the line was damaged as I removed the bender and yes I did have to start again!

Don't recall an issue at the tank end on my 7, does the 8 have a lot less space to work with here?
 
And DON'T do something dumb like this;


Don't recall an issue at the tank end on my 7, does the 8 have a lot less space to work with here?

I can't speak about the 7, but that first bend out of the fuselage was not a problem. Where I'm having the issue is where the fitting exits the leading edge of the tank. I have some weird variances
.... from the plans that I don't know why they happened. Van's drawings of the completed line show the line coming out of the tank slightly above the chord line - don't know how they did that - then their attach fitting on the fuselage with the optional hole sits noticeably lower than mine. Their hole lines up very nicely with the tank fitting so that it only has to take one simple 90 deg bend to the aft to connect up with the line from the valve. (plans show a bulkhead fitting to connect the two)

I may have to go under the whole attach bracket or else make a new larger bracket with the pass through hole lower to line up with the fitting.

I had a panic attack this morning thinking maybe I made the wings backwards or put in the center section upside down. :eek:

Thanks for the replies! I may try the sand trick. :)

here's a photo: Short tube to show line exit from tank
dcznrr.jpg
 
Do you have inverted oil? If not, you'll lose oil pressure long before you lose fuel pressure, with the stock pickup. Flop tube plumbing introduces numerous additional failure points. Make a rational choice.

Charlie
 
I think I got it.

Thanks again for the tips. I spent the morning making long tubing into short tubes and flares, but I got a pretty good result. I did go with the sand filling tip, and used the flaring tool backwards. I was able to get the bend radius (including coupling and the stubborn end of the tube that doesn't like to bend) from 2" down to 1 3/4" If anyone is having a similar issue, I have the technique I used on this page: https://www.facebook.com/BZsRVproject/photos/pcb.1721149757961405/1721149604628087/?type=3&theater
 
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