wing tank plumbing

[VictorBravo]

Re: wing tank plumbing

Install a check valve to prevent fuel from flowing out of the main tank and into the wing tank lines???

All of this would require an approval to be legal of course. However, from a purely mechanical standpoint, I'd vote for the two-valve system instead of the check valve. One at each tank outlet at the wing root, one at the T where those wing feed lines go into the tank, and then a "stock" main shutoff valve at the bottom of the main fuel tank upstream of the firewall.

This means a total of four valves in the airplane for people wanting the utmost in leak-stoppage ability, but indeed each of them would have a function. But doing it this way adds its own complexity and actually adds more locations where some piece of hardware could leak.

So it's a judgment call - choose between lowest parts count/least # of leak points, and being able to isolate a leak from the most angles.

Re: wing tank plumbing

No chance there's an elbow (pointing up) on the inside of the tank?

no

[NY86]

Re: wing tank plumbing

nothing else there, just a pipe thread fitting to fill the tank from the back.

No chance there's an elbow (pointing up) on the inside of the tank?

[Hank Jarrett]

Re: wing tank plumbing

Neat, mine was set up to be down while draining and either forward or aft when closed (can't remember). The placard was original and didn't allow for up and forward.
Since I am making all new placards it would be easy to change. Think that violates any "rules"?:clue?::
Hank

I also like the larger "plate" behind the valve so the handle doesn't rub the headliner and make a hole or tear in it.

Re: wing tank plumbing

Is something else connected there too? Any chance there's a standpipe inside the tank to put the outlet above the normal fuel level? (Otherwise, why wouldn't it be at the bottom?)

nothing else there, just a pipe thread fitting to fill the tank from the back.

[Mark Julicher]

Re: wing tank plumbing

The same logic for the nose tank is why the fuel tank on a Willy's Jeep was under the driver's butt. AND there was the potential for taking a bullet and scorching valuable anatomy.

[flyguy]

Re: wing tank plumbing

Nah, I'm not going to comment on the logic of putting 12 gallons of highly flamable fuel just above the pilots lap. Perhaps the same train of logic for the T ? Chuckle.
DC

[NY86]

Re: wing tank plumbing

it tees into the back of the fuselage tank near the the bottom.

Is something else connected there too? Any chance there's a standpipe inside the tank to put the outlet above the normal fuel level? (Otherwise, why wouldn't it be at the bottom?)

[Howard Wilson]

Re: wing tank plumbing

Not a head banger. I hang an old wristwatch on it, and start it when the engine starts. Remember "Time in Your Tanks"? h

Re: wing tank plumbing

I'm not familiar with how the wing tank plumbs into the header. Does it simply T into the line going to the engine? "Generally", when there is a transfer line, it dumps into the tank in the airspace so that, should the line break, fuel will not siphon out.

it tees into the back of the fuselage tank near the the bottom.

[NY86]

Re: wing tank plumbing

I'm not familiar with how the wing tank plumbs into the header. Does it simply T into the line going to the engine? "Generally", when there is a transfer line, it dumps into the tank in the airspace so that, should the line break, fuel will not siphon out.

[N96337]

Re: wing tank plumbing

I just got a field approval last year for mine and a friend's as well, to put the valve up in the wing root, where it needs to be. My FSDO and ACO had no problems with this at all, and in fact said it was a much better placement than original to the STC, which has the valves under the panel. We mounted the valves to an aluminum plate on the inside of the wing root area of the cabin.
John

[VictorBravo]

Re: wing tank plumbing

Two valves would work well mechanically, if you have the room. Because you would have to mount the second valve at the bottom of the tank, which would shut off all flow in or out from the wing tank feed lines. THEN you would mount your T fitting behind (upstream of) that valve. This will put the lines and the T fitting further aft in the airplane, which could possibly interfere with something else behind your panel.

[Hank Jarrett]

Re: wing tank plumbing

Since I will probably rarely use the wing tank in mine I was thinking the same thing (two valves). The lower valve keeps the main tank from leaking through the transfer tube and the wing mounted valve is easy to see and provides a great reminder that you left it open when you bash your head on the handle. Only problem I see is that it really isn't "legal" to add a valve and the problem of forgetting to open the lower valve and not really transferring fuel.
Since I don't really use my wing tank yet and the $#@%&)(*&! handle smashes into my knee so much, I like to take the handle off and put it in the glove box. If there is no fuel in the wing anyway I don't see any problem in not being able to open the valve.
My IA might disagree, but it is on when he sees it.
Hank

[mulwyk]

Re: wing tank plumbing

Safety is my primary concern here. I hate to admit it, but I have a deep fear of onboard fire (nightmares and all). So, Hank and Bill, I read your posts with extra interest.

It's going to be a soft aluminum tube and wing root mounted valve for me. I'm even thinking about a second valve, at the inlet to the main tank, for use in an emergency situation. What do you think?

And Dave, please, post those photos.