muzzlemaggot

My Feedback: (7)

Alrighty...here's the situation. I'm attempting to configure my old trainer airplane for a dual tank setup in preparation for an upcoming endurance flight. Existing tank in the fuse is 8oz (inline with carb) with absolutely no room elsewhere inside the fuse for an additional tank. I have a 16 oz tank that I'd like to supplement the 8oz tank with. I was thinking of securing it on top of the wing at CG and running the muffler tap line into the pressure inlet of the bigger tank, which would allow fuel to flow through the clunk line and then into the pressure inlet of the smaller tank. My concern is flooding or leaning due to the height difference with the larger tank being a few inches above sitting on the wing. I have no experience in doing this and would appreciate any comments or suggestions before I get started. Thanks to all.

gadix

My Feedback: (2)

just follow ARCHIMEDES law and u r good!

first tank is you "fill" tank the last tank is the one with the vent/prss and carb fuel line.

gadix

My Feedback: (2)

best way is to do a test on the bench and than put back to the plane

tuskegee

My Feedback: (1)

I have a dual tank on my BAe (and just like gadix said). your top tank leave as is, just take the tube that was to your engine and run that end into 2nd tank. That will fill it as the fuel is used from the 2nd tank. leave the muffler line to the muffler.....now on the 2nd tank run one line to the engine and the other will be your fill line.Now when you fill your bird the 2nd tank will fill then the (top) 1st tank.
Tuskegee
U.S.Army(ret.)

Sport_Pilot

Clear as mud. I think they are saying that the engine will draw from the top or new tank on top of the wing and muffler pressure will push fuel from the bottom or existing tank to the top. I would think that would work. The tank is higher, but you will adjust the fuel mixture to compensate. It won't work inverted, but I think if you are strapping it on top of the wing you won't be doing that.

muzzlemaggot

My Feedback: (7)

So, in other words, the new 16 oz tank sitting on top of the wing now becomes the supply to fuel the engine. Am I understanding this correctly? In that case, will muffler pressure be enough to force fuel from the existing smaller tank upwards into the larger tank? For some reason, I would think it would make sense to keep using the existing smaller tank as the fuel supply, but maybe I'm just way out there....Thanks thus far for the replies.

Brian

Sport_Pilot

I think that would work too, I think there would be enough muffler pressure, and the work of it pusing uphill would probably work against the gravity flow to keep it more constant, but I think it would work either way. Best to try and if it doesn't work try the other.

w8ye

My Feedback: (16)

Will work either way

Six of one and one half dozen of the other

muzzlemaggot

My Feedback: (7)

Well, I tried both ways. It definitely would not work drawing fuel from the bottom existing tank...fuel just gushed out of the carb, hydrostatic locking the engine and all. I reversed it to draw fuel from the new top tank that's on the wing CG and it appeared to work like a champ, other than richening up a bit during flight. At least I didn't have to trim it during flight, with it being mounted centerline CG. I'll lean it a click or two and see how it goes. Thanks to all for the replies. This has been a learning experience, but not entirely too frustrating. I appreciate it.

Brian

Sport_Pilot

Did this push fuel from the bottom tank to the top? I should have thought that you would have to clamp off the fuel before starting if drawing from the bottom tank first.

muzzlemaggot

My Feedback: (7)

Yes, it pushed the fuel uphill along a course of about 10" of line. The engine pulled fuel from the top tank. Bottom tank emptied first as it continued to keep the top tank full.

muzzlemaggot

My Feedback: (7)

I must admit, however, my plane looks somewhat ghetto with a 16oz tank velcro strapped to the top of the wing. Oh well...it's only temporary for the endurance flight.