Fuel Tank Question

[GAHorn]

I'm sure he used MS27039C types (which are structural stainless.)

[W.J.Langholz]

Ole Pokey

Let me know how the project goes. I see my left one is stating to dribble a little also, may have to wait til warmer weather.

[GAHorn]

If you have fuel stains streaming back along the top of your wing, you may have a simple fix if you're as lucky as I am. I had installed a second vented cap on my left side (to match the one required by the AD note on the right) and it turns out that the screw which holds the anti-siphon vent had simply loosened up. It wasn't obvious. It went on for at least six months and I was delaying investigation because I didn't want to know about the suspected gasket problem.
When I finally looked into it, turns out that it was merely that screw which descends down through the center of the vent which was loose. Tightened the anti-siphon valve and....VOILA!
(MEK takes the fuel stains right off, but BEWARE if you have a painted wing instead of an original, natural aluminum one!)

[W.J.Langholz]

If you have fuel stains streaming back along the top of your wing, you may have a simple fix if you're as lucky as I am. I had installed a second vented cap on my left side (to match the one required by the AD note on the right) and it turns out that the screw which holds the anti-siphon vent had simply loosened up. It wasn't obvious. It went on for at least six months and I was delaying investigation because I didn't want to know about the suspected gasket problem.
When I finally looked into it, turns out that it was merely that screw which descends down through the center of the vent which was loose. Tightened the anti-siphon valve and....VOILA!
(MEK takes the fuel stains right off, but BEWARE if you have a painted wing instead of an original, natural aluminum one!)

Ok George

I feel a little like going out on my first snipe hunt....this is a little like looking for the bull ring on a heifer shaft, but help me out and point in the direction of the anti siphon valve location. Yes I did get out myservice manual and read through everything on fuel tanks and still couldn't locate it.

Thanks

[blueldr]

The anti siphon valve is in the fuel tank cap. I'm speaking of the cap that was required by the AD. This cap is vented to atmospheric but incorporates a one way check valve that precludes fuel siphoning out of the filler neck, particularly with full tanks and a relatively nose down flight attitude.
It is common to have fuel siphon out of the cabin top "goose Neck" vent if the tanks are full and the airplane is in a steep nose down descent. This will cause the cross cabin inter tank vent line to flood and result in fuel siphoning out and wetting the top of the fusealage.

[GAHorn]

And even more common when landing with full tanks in a wheel landing and hitting the brakes hard,...fuel can spit out the gooseneck onto the windshield. (A "cure" was created that was worse than the disease, when Cessna came up with a check-ball mod for the gooseneck. It was ultimately removed by subsequent additional service bulletin. Occasionally I still find someone with the check-ball mod and I have to talk them into removing the mod and sealing up the additonal vent hole in the aft side of the gooseneck.)

[170C]

Just a quick comment on the fuel stains on the wing (or elsewhere). Scrubbing Bubbles (product from S C Johnson used to clean kitchen & bathroom fixtures) works great to remove the fuel stains and doesn't hurt the paint. Available at grocery stores, Wal Mart, Sams & multiple other outlets. Also works good on removing oil & gunk from the belly. On the oil/gunk, it works best to spray an area about 1-2 ft square, then wipe it off with a rag. If there is any oil left, repeat the process. Unless the oil has been on the belly for an very long time one application usually removes it. After the entire belly has been cleaned, you need to go back over it with a clean cloth to remove a slight haze. That belly will then shine like a new paint job. This was passed on to me by our good friend Joe Harris several years ago.

[GAHorn]

Just a quick comment on the fuel stains on the wing (or elsewhere). Scrubbing Bubbles (product from S C Johnson used to clean kitchen & bathroom fixtures) works great to remove the fuel stains and doesn't hurt the paint. Available at grocery stores, Wal Mart, Sams & multiple other outlets. Also works good on removing oil & gunk from the belly. On the oil/gunk, it works best to spray an area about 1-2 ft square, then wipe it off with a rag. If there is any oil left, repeat the process. Unless the oil has been on the belly for an very long time one application usually removes it. After the entire belly has been cleaned, you need to go back over it with a clean cloth to remove a slight haze. That belly will then shine like a new paint job. This was passed on to me by our good friend Joe Harris several years ago.

Yeah, but it really slows airplanes down. (Joe)

[W.J.Langholz]

AH...HA.... you were talking about the "Fuel Cap Vent" here I was looking for some highly sophisticated valve either inside the fuel tank or somewhere on the fuel line between tanks.............I guess I can put my left wing back on the plane now

[170C]

By George, George, I think you are right regarding the Scrubbing Bubbles slowing down the airplane However, there still remains that question, never resolved, of which plane it slows down "the most", a red one or a green one Must be that having the belly so slick, shiney & clean that the air somehow is attaching itself to that surface for a longer period of time just so it can admire how nice it really is Maybe we can get our resident rocket scientist, Miles, to give us a better explanation of this via some formula

[GAHorn]

By George, George, I think you are right regarding the Scrubbing Bubbles slowing down the airplane However, there still remains that question, never resolved, of which plane it slows down "the most", a red one or a green one Must be that having the belly so slick, shiney & clean that the air somehow is attaching itself to that surface for a longer period of time just so it can admire how nice it really is Maybe we can get our resident rocket scientist, Miles, to give us a better explanation of this via some formula

I'm afraid to bring this subject up again. (Joe is much better connected than I these days, and likely in a better position to influence such things.)

(I still don't know how he managed to get a green robe.)

[170C]

The green robe---Joe has connections in higher places

[flyguy]

By George, George, I think you are right

AAAAAAAAAAAAAARRRRRRRRRRRRRRRRGGGGGGGGGGGGG!!!!!!!!!!!!!!!!!!!!!!!!!!!!
GEORGE RITE????????????????????????? OOOOOOOOOOOOOHHHHHHHHHHHHNNNNNNNNNNNNNNNNNNNNNNOOOOOOOOOOOO

[mdsmith]

As this seems to be the same or similar assembly for my 1957 C172, have a related question about removing frozen screws. Two, one in each wing won't budge. The popular EZ-out from Lowes didn't work for me. I ground slots in the others after the Phillips head stripped. I expect to lose the heads of these two remaining screws trying to get them out. I'm not sure what type of anchor nut is used along the rear of the leading-edge when these two are located, but I am wondering if a punch could be used to push the screw shaft done to clear the fuel cover plate holes, assuming an NAS444-5 is used. The longer screws along the leading edge might indicate this type of tinnerman anchor nut is not correct: unclear in the parts manual. Please comment as possible.
Mike
King George, VA

[DaveF]

Bathe them in penetrating oil for a week or so, then try a left-hand drill bit. You'll either drill out the screw or the vibration will cause it to loosen and back out. That worked for me, removing rusted screws on my old Cherokee.