One Fuel tank is pressurized

[2356]

Do you have the vent on the top of the cabin?

[rfrederick]

Blaine, I spent many hours for the past 2 weeks getting the shine you see on the upper fuselage, the reason for my angle is it shows the part I got done so far the top of the doors and fuselage under the wing root are pretty well pitted. areas of the plane I haven't gotten to looks almost gray. the previous owner and the one before him. The most recent owner was not around much in the past 5+ years (medical issues) so the 140 sat for long periods.

[rfrederick]

George, I haven't seen anything that resembles a vent on top of the cabin. I looked online and this was what I was able to find for the vent, I dont have anything looking like it.

Screenshot from 2020-06-01 13-55-52.png (12.52 KiB) Viewed 4416 times

[8474]

Hi Rick, ok well it sounds like what you started out with is what I have now as well. I also started polishing in the aft fuselage area and after a whole lot of elbow grease I was able to get some parts nice and shiny again. I have an A model so that means I have both sides of the wings to clean and polish as well....a whole lot of real estate I sure wish there was a quick method, but it looks like it will just be hours of rubbing.....

[8474]

Do you have the vent on the top of the cabin?

His airplane is a LEFT RIGHT only system, not a BOTH system and since he says it is holding pressure in both tanks then there can't be any interconnecting vent line. The only venting is thru the caps.

[6643]

i know it hasn't been made clear, and the picture of the fuel valve ads to the confusion, but I believe he does have the left-right-both system, and does have the interconnecting vent line. What he does not have is the forward facing vent from the 140A. If he did not have the interconnecting vent line then he would have run out of fuel in the tank that had the bad cap. Also, the pattern for the Left-right-off valve doesn't have a position between left and right.

[8474]

I see now that from that picture it does look like it has a BOTH position, marked as ON.

However you did ask him if he had positive pressure when he opened both caps or only one. You correctly said that if there was an interconnect line then removing one cap should relieve pressure in both sides, but Rick came back and said both hold pressure if I understand his response. That would indicate no interconnect. I don't think he would have run out of fuel if there was no interconnect as the A model caps do allow air in, just not out.

As Mac said, many mods have been done over the years that may not have been correct and unless I'm missing something it looks like a BOTH fuel valve was installed and no interconnect line added and A model fuel caps used.

[2356]

Without the forward facing vent, what keeps the tanks from creating a vacuum.

[8474]

Vented fuel caps

[6643]

Rick came back and said both hold pressure if I understand his response. That would indicate no interconnect.

Unless I misunderstand him, opening either cap relieves the pressure in both tanks, therefor he does have the interconnect.