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Fuel Pick-up

Craig Coffin

I'm New Here
We are doing final assembly on the fuel tanks of an RV-9. The plans show to close the end and make several saw-cuts over the last inch of the fuel pick-up, no problem. Another member for our EAA group stopped by the hanger and said, no, you want to install some type of screen pick-up. The band-saw cuts will be too large and potentially allow a piece of foreign debri to make it into the fuel system (Proseal bit or something that may come in when re-fueling). I would like to hear some opinions on this from other builders, anyone had problems with the way Van's shows to do it? What other options are there?
 
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you will be fine with the saw cuts, just put an inline filter after the tanks. What happens when the nice screen from the preformed lines get plugged. I'd rather change an inline filter once a year on anual.
 
I respectfully disagree.

you will be fine with the saw cuts, just put an inline filter after the tanks. What happens when the nice screen from the preformed lines get plugged. I'd rather change an inline filter once a year on annual.

Yes the saw cuts will work fine, if properly deburred. Mine flew for 13 years that way. However, I think the screen is better. The "screen pick-up" is much larger in area and much less likely to become clogged.
YMMV!
 
Yes the saw cuts will work fine, if properly deburred. Mine flew for 13 years that way. However, I think the screen is better. The "screen pick-up" is much larger in area and much less likely to become clogged.
YMMV!

then why do you need it?
 
Lets say

A large chunk of proseal breaks off...It could get sucked into the 3/8th line and potentially go through the valve and end up in the only filter you got.

I once had a 9" length of proseal sliver get caught in the fuel drain...Definately would not have liked that to get sucked into the fuel line.

Its just a good idea to have a coarse strainer IMO

Frank
 
OK now I will disagree with myself..:)

I have flop tubes in both tanks...They don't have a screen on them.

But I do have a filter in line in the wing roots (That happens to be where my FI pumps are)...As said previously, easier to pop the root fairings off and change out a simple filter which avoids opening the tank to clean the screen.

That better maintenance access has to be balanced with the fact that it will be very difficult to clog up a screen inside the tank.

Frank
 
totally agree, the filter right in the wing root right out of the tank. thats what I'm doing. Forget any filtration system in the tank, very hard to get to. I work on cars, I know what happens when the sock in the tank gets plugged, it's out with the tank and the mess and trouble, yuk. Replace an outside filter, piece of cake. Did you know that the Dodge truck runs with a filter in the tank, no outside filters. What a pain, you have to remove the tank and replace the fuel pump. What a pain, and expense, wow.
 
The fuel pick up tube screens supplied by Van's are course at best. If you ever plug them up, or have enough garbage in your fuel tank to do so, you will be inside the tank for a thorough cleaning and inspection anyways, no different than if the same happens on your external filters. I guess you dont need them if you double up your filters, but having them doesn't hurt and may prevent something like a big chunk of proseal or other gross particle plugging up the pick up directly. Probably a very unlikely occurence.
I have Van's pick up tubes and the standard AFP single filter set up.
 
Fuel Pickup Cutting Option

I made my pick-up tube cuts using a Dremel tool with a ultra thin cut off wheel. You can make them as small as the thickness of heavy paper and the cuts are clean. I made mine about 20 thousandths wide. After the cuts are made you can ream out any burrs inside before you crimp the end. The end result is actually a pretty professional looking job and there's never any chance of a screen falling off or coming loose.
 
I kept having troubles with the pick up tubes. I felt so stupid. I would get the bend perfect, but find I forgot to install the fittings. Or I would mess up the flair, or the saw cuts would be terrible. Out of 6 attempts (I ordered two sets of replacment tubing after I screwed up the first set) I was only happy with how one turned out. I broke down and bought the premade pickups from Van's and it fit like a champ.

But, I did ask one of the Van's engineers about the saw cuts and he said doing it that way has been successful for over 20 years.
 
Pickup tube seal question

Hijacking or reusing this old thread because it's the same topic as my question.

I'm building an RV9A QB, which means I don't have a tube of Proseal handy. One of the last tasks to do with the wings for a while is assemble the fuel pickup tube to the fuel tank access plate T-718. I'd like to seal this assy with something, and wonder if structural epoxy T-88 will serve to create a leak-proof seal similar to Proseal. The T-88 box says "will bond to most clean surfaces including...aluminum...." and "When fully cured T-88 is unaffected by...gasoline, and most chemicals."
 
Before you seal up youre quick build tanks double check the vent tube flare fitting and make sure it is tight and put some proseal on the fitting also,if the vent line leaks at that joint every time the tank builds any pressure fuel that has leaked into the vent line will be pushed out the vent tube even if the tank is not full. Based on past experience.
 
.... The T-88 box says "will bond to most clean surfaces including...aluminum...." and "When fully cured T-88 is unaffected by...gasoline, and most chemicals."

If you do that, it might be a bit difficult to get that plate off for future maintenance.

Van's sells small tubes of proseal, get one of those.
 
And now for a short public service announcement:

Don't monkey around with fuel system design.*

Thank you.









*It's near the top of the list in the "Builder Error" category, and none of the crashed builders thought their idea was bad. Yes, there are sometimes carefully considered reasons to redesign, but please, get some serious, qualified review.
 
And now for a short public service announcement:

Don't monkey around with fuel system design.*

Thank you.









*It's near the top of the list in the "Builder Error" category, and none of the crashed builders thought their idea was bad. Yes, there are sometimes carefully considered reasons to redesign, but please, get some serious, qualified review.



LoL - are there any University Professors or retired NASA Engineers......
 
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