Wing tank plumbing

[Robert Lees]

Re: Wing tank plumbing

Rob, what kind of primer is that?

Well, before we get to primer, we have to discuss corrosion inhibition & protection and etch prime.

All my steel fuselage tubes and my aluminium fuel lines were painted with two-part etch prime and then two-pack epoxy primer, followed by a two-pack acrylic gloss-coat.








Just kidding you, I knew what you meant! It's a cheap Aircraft Spruce primer. It works, not brilliantly, but it works.

[M Towsley]

Re: Wing tank plumbing

Rob, the primer in the dash. So sorry for the misunderstanding.

[Robert Lees]

Re: Wing tank plumbing

I knew what you meant, Marty!

It's still a cheap ACS primer...you need the part number?

[M Towsley]

Re: Wing tank plumbing

Sure, just never saw one that looked like that one.

[Hank Jarrett]

Re: Wing tank plumbing

Copper was the old standard in aviation, as in automobiles. Problem is copper cracks when flexed over an over, even a little angle, and when it does with fuel you have a good chance of burning. Small diameter lines can flex much (VERY much) more than larger ones so the fatigue limit probably won't be reached for a primer line, but then, no one expected these planes to be flown for almost a century. The next time I rework mine I will be replacing the primer lines with new, so it should be good for another 70 years (unless they come up with something better, the regular copper fuel line are LONG GONE on my plane). If you EVER see any cracking, especially near the ends or in the flares (tend to be the worst because the end is restrained), you could be approaching the fatigue limit there. CHANGE it. I won't use copper regular fuel lines at all because they just don't last in a vibration environment (lots of small flexes over a small angle are as bad as a smaller number of bends at a larger angle and the bigger the tube, the higher the stress at the extreme fiber).

Some here don't agree with me, and some in the WW-I replica group think I am Chicken Little, but I just don't think it is worth burning alive over.

Hank

[Bravo 6]

Re: Wing tank plumbing

Robert,

Thanks for the great under panel shots! Very clean installation!

Strongly considering changing out the fuel line to aluminum and moving the valve under the panel.

[Guest]

Re: Wing tank plumbing

BTW, Robert, really nice, clean installation! I am hoping to incorporate a headliner and am contemplating how to deal with the fuel valve if I don't relocate it?

Hi Greg,

My installation looks just like yours.

Copper line, valve at the wing tank.

I have a plastic headliner.

There is a small cut out around the valve handle, the cut out is covered/trimmed with a small square of fabric that fits the valve stem and cut out.

It originally had velcro at the edges for easy removal. Velcro may be gone now and replaced with glue. Its old, a 1982 installation.

A friend had t-craft too. He had the panel located valve. He wished he had wing tank valves. The panel valve was in the way.

BTW- I recall that the placard needs to say to transfer fuel when the main is half full, anybody else recall that? Or am I thinking of W & B stuff.

Dave

[Bravo 6]

Re: Wing tank plumbing

Dave,

I thought I copied that right out of the document? I will double check it though?

[Robert Lees]

Re: Wing tank plumbing

Sure, just never saw one that looked like that one.

Aircraft Spruce P/No is 05-19920

Rob

[Bravo 6]

Re: Wing tank plumbing

From the TC.


NOTE 3. Required placard adjacent to shutoff valve of right and left wing tanks: “Refill main tank in level flight only”.

[Guest]

Re: Wing tank plumbing

From the TC.


NOTE 3. Required placard adjacent to shutoff valve of right and left wing tanks: “Refill main tank in level flight only”.

Thanks Greg,

My bad.

I must be remembering a weight and balance issue.

It must be that I am remembering about mine it has to be transferred when the main is down to a certain level when you have both wing tanks full and full seats in order to keep it in the CG range.

I don't use it that way too much so it is a vague memory .

Dave

[M Towsley]

Re: Wing tank plumbing

Thanks Rob!

[Guest]

Re: Wing tank plumbing

There is another one that indicates to only do so when the main tank is half full, or less. At least my two BC-12's have had that one.

Thanks Rob!

ahhh

Thanks Marty.

I am going to go look at mine.

I am pretty sure that I am getting lots of things mixed up now!

I have W&B issue as well.

My loading schedule has this note; "max fuel all tanks 12 gal nose, 12 gal wings, 294 lbs in seats, 0 baggage, transfer wing fuel before main drops below 6 gal"

Dave

[M Towsley]

Re: Wing tank plumbing

Dave,

Now I am starting to question myself. I cannot remember if I read it or if it is a placard. Temps are -4 right now and I am not in the mood to run out to the hangar to look. I should have some pics of my panel, hopefully I took one of that. I will look.

[Hank Jarrett]

Re: Wing tank plumbing

Different year planes had the valve in different places. Pre-war they were under the panel, but before you move yours make sure it is OK with your IA. A BIG down side of under panel valves is the lever is down when transferring fuel and it hits your leg. The down sides of a wing root valve is if you forget it is down after a flight you will gash your head on the lever (in the original configuration). Many guys have flipped the valve so it is forward when transferring and UP when closed or at an angle so it is 45* fwd while transferring and 45* aft when closed. Not the factory set-up, but makes a LOT more sense.

There were also TWO placards required. One said not to transfer fuel until the main was half empty and the other to transfer in level flight only (the second wasn't in the early planes, I don't have anything saying it had to be retrofitted). There is also supposed to be a placard by the valve showing what position was closed and open.

Most IA/A&Ps have NO IDEA what is required. We need to educate them with documentation. Anyone have paperwork showing when the placards were put in? I have photos of most of them and will dig them out.

Hank