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Header tank holes and material?

PostPosted: Wed May 09, 2007 2:06 am
by Dave Krall CFII SEL SES
I'm curious, with reported header tank leak problems not unusual, why aren't the holes tapped with threads after drilling instead of apparently just using push ins with seals as the manual appears to call for?

Old manual

PostPosted: Wed May 09, 2007 5:53 am
by b1x4nqb
Dave,

I just drilled mine out yesterday and the manual is out of date.  The new aluminum tanks do require you to drill and tap them.  Remember to drill one size under for the hole and use EZ-Turn on the threads.  One thing I realized was at the bottom for the curtis valve, you need a male-to-male fitting.  My kit was missing one but I'm sure the local hardware will have one.  Anyway it goes out the bottom on a barbed hose fitting, onto hose itself, then reverses onto another barb fitting which is connected to a male to male fitting and finally into the curtis valve.  Whew, sounds more complicated than it really is.

Paul

PostPosted: Wed May 09, 2007 4:48 pm
by Dave Krall CFII SEL SES
Thanks bix4nqb,

I wonder why they even give us that manual! The fittings I have are all thread less so I asssume I need a whole set of header tank fittings?

Many Thanks for the heads-up!

DJK

fittings

PostPosted: Wed May 09, 2007 10:03 pm
by b1x4nqb
Dave,

You'll need 5 small barbed hose fittings for the header tank and 2 large ones for the wing tank fuel filters.  That is assuming you have the aluminum header tank.  The header tank has 2 on the top feeding it, 1 to feed out to your engine and 1 out the bottom towards the curtis valve which connects to a hose piece which connects to another (the 5th) then reverses into the curtis valve itself.  Hope that helps and is not confusing??

Paul

PostPosted: Wed May 09, 2007 11:51 pm
by DaveU
Dave,
Here is a picture of the top of my header tank.  The barbs are 1/4" barb by 1/8" pipe I think.    2 of them drilled and tapped into the top, one into the side where there is a doubler welded on and one out the bottom to lead to the curtis valve.  I bought the fittings at menards.  


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Dave

FWIW here's how I did mine

PostPosted: Sat May 12, 2007 2:13 am
by KevinC
I didn't like the idea of having hose under the floorboard where I couldn't inspect/replace it, so I hard lined it to the shut off valve.  Some pix.  I brazed the lower female brass connection to a washer and riveted the washer to the tab on the fuselage - didn't like the idea of just using epoxy

K


Image

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tap & Die set

PostPosted: Sun May 13, 2007 10:01 pm
by b1x4nqb
Not really being a mechanical guy I went to go buy a tap and die set.  Went down looking for the size the manual states and luckily I brought along my fitting to be sure I got the right one.  Anyway those guys at the store had no clue and when I opened up all the kits, none of them fit the threads.  Again, I'm new at this so in researching the LEAF book, etc. the threads appear to be NPT threads which according to my brother are rather common in the fitting world, just not your everyday car shop supply.  Needless to say, I'm going over to Bro's house tomorrow to cut some threads with some of his bazillion tools.  Wish I was building in his garage!  Anyway I just thought I would pass that along to those learning like myself.

PostPosted: Sun May 13, 2007 10:41 pm
by Dave Krall CFII SEL SES
Thanks for the heads up on the threads, Paul!
When you know for sure the name & size, could you let us know?
Many thanks.

Taps

PostPosted: Thu Jul 12, 2007 6:26 pm
by pdeinin
I went to Lowe's to get taps for the fittings in my kit.  It is a 1/8" NP-27 that requires a 21/64" hole.  
Worked great sealed with EZ-turn.

PostPosted: Wed Jul 25, 2007 1:41 pm
by Dave Krall CFII SEL SES
It would appear mine has the drain hole drilled in the center of the wrong end (nearest the welded square plate on the side of the tank) so local service dept wants to know what kind of metal it is. Anybody know for sure? Thanks in advance.

PostPosted: Wed Jul 25, 2007 4:50 pm
by pdeinin
Dave Krall CFII SEL SES wrote:It would appear mine has the drain hole drilled in the center of the wrong end (nearest the welded square plate on the side of the tank) so local service dept wants to know what kind of metal it is. Anybody know for sure? Thanks in advance.




Dave,  You appear to be saying that the hole is at the same end as the welded square.  This would be the right end because it allows the drain in the single hole on the bottom with the outlet to the engine just a few inches up on the side.  However, if I am misunderstanding, I don't think it is a problem.  You just need to make sure you end up with two holes on the top (they don't have to be in any particular location and you could use the existing hole along with one other), one hole on the bottom and the 4th hole on the side in the welded square a few inches from the bottom.

PostPosted: Wed Jul 25, 2007 7:55 pm
by Johnny C!
Dave,
 That's the correct end for the single hole.
It goes to the drain valve. The square plate
gets a barb that goes to the engine.
The two holes in the other end (top) accept fittings
coming from each wing tank.

John

PostPosted: Thu Jul 26, 2007 12:45 am
by Dave Krall CFII SEL SES
Johnny C! wrote:Dave,
 That's the correct end for the single hole.
It goes to the drain valve. The square plate
gets a barb that goes to the engine.
The two holes in the other end (top) accept fittings
coming from each wing tank.

John


That would put the barb that goes to the engine about 4" down from the top in my header tank's case. The others I've seen have that square plate about 4' from the bottom with its single drain hole, allowing more useable fuel, and about a cup or so of inflight water trap, the way I see it.