guille2006

Hello guys... this is the problem: I'm being forced of putting two tanks in my plane; how can I be sure of burning the fuel uniformely; mean: not to use one tank entirely (and receive an engine shut) while the other is still full...
Other usefull information:
- Each tank is 3 lts (almost one US gallon).
- Separation between them is about 80 cm (tip tanks).
Can anybody send me a usefull-practicable layout?
Thanks on advance
Guille

mick15

Pipe the tanks in series, that way they will drain one after the other.

m

guille2006

OK Mick; I thouth on that but the problem is to not have a wing tip "full" and the other "empty"... I'll have three litters at rigth and none at left. They must remain more or less equilibrated.

mick15

Can you be a bit more specific with the model and the layout?

m

guille2006

It's a kind of Mig-21 but It has to flight for a long time and fast (a couple of hours or more if possible). The Fuselage comes a 100% for the turbine servos and betteries and the fuel will be on the underwing tanks (3 lts each).
Thanks for your interest...

Terry Holston

My Feedback: (1)

A couple of HOURS??????????

guille2006

Yeah!!!! I know it's a nigthmare!!!!!!!

jason

My Feedback: (1)

So a 32" wingspan with a US gallon on each wing tip and a 2-hour flight time... Good luck to you. If you are serious then I think your best way would be to draw from these tanks in parallel with equal lengths pipes on the vents and feeds, this will ensure that the balance remains correct and both tanks fill and drain at the same rate.

Jason

digitech

My Feedback: (10)

not only that , you need to fly the same laps right side and left hand side...

guille2006

No no... I used the term wing tip tank for a quick understanding. Fuel tanks are partialy under the wing and partially on the wing. There is U2 with more or less the same configuration: http://www.aviation-central.com/1946-1970/afka0.htm
Real wingspan is about 2 meters.

KC36330

I've gotta ask, what turbine is gonna fly this two meter plane for two hours on a gallon of fuel??? i need a few of em because these blasted JetCat's are killing my mileage.

guille2006

Two gallons... and we want to fly as much as two gallons permits.

KC36330

thats about 30 min for a single P-60/P-70/Wren 54

guille2006

That's OK... no problem.
I've still two tanks to manage.

KC36330

Jason explained how to do it in post 8, and No you don't have to fly the same number of left/right turns for it to work.

lov2flyrc

My Feedback: (24)

Just do as Jason suggested above however, I would cross vent. Make the left wing vent to the right wing and the right wing vent to the left. Have both tanks drain to a center header.

Todd

guille2006

Thank you guys... really helped me.

joeflyer

My Feedback: (48)

Here's a schematic of a typical parallel tank set-up. Take care to insure that each tank's plumbing, including the tubes and clunks inside the tanks, are identical. That will insure that they will drain and fill close to the same.

After plumbing my tanks I always drain and fill them several times using my fill station as a check. Shorten the lines to the tank that drains/fills the slowest a little bit at a time until you get them about equal. Don't waste your time trying to get them exact, if they are within a couple ounces of each other you are good.

Joe

guille2006

Hey joe!!! You're lovely!!!
I'm already working on that!!

Thanks to all
Guille

guille2006

Just to update you guys...
tests with the double tanks went really good considering the advices you gave me... I received a decently equilibrated fuel consumption on my on ground test dispositive. in-fligth test will take place in a couple of weeks.
Thanks again
Guille

Synthetic

My Feedback: (18)

Guille,
Can you tell us how you will be able to fly for two hours without refueling in air? Myself, I am not sure how this can be done unless you pack in a lot more fuel than two gallons. You've got me me curious.
Thanks and Good Luck,
Don

flyexperimental

In a turn the gas should be sitting pretty much in the same place as it sits in level flight.Just like "the ball", slip indicater on full size aircraft stays in the center during a turn.The high g's of jet flying would even keep the gas planted in the bottom of the tank.

KC36330

the flight of an RC plane is far from perfect coordinated turns and the fuel is constantly in motion moving around the tank, even sloshing violently.

vasek

My Feedback: (4)

Stupid question: why do you want to fly 2h or more?

flyexperimental

Both tanks,even if they are not sitting next to each other are affected by forces equally .I can not see turning more in one direction,verses the other will make one tank drain quicker than the other.If the tanks drain evenly while sitting still they should do the same in flight.When the fuel does get tossed around it will do so in both tanks.