bob_nj

My Feedback: (62)

Anyone have an explanation or diagram as far as hooking together two gas tanks in a giant scaler?

JoeAirPort

My Feedback: (41)

I'm pretty sure the jet guys do this all the time. Might want to check with them.

bob_nj

My Feedback: (62)

I've done it with glo, and not sure how it works with jets, but just uncertain when using
a draw system like gas, as opposed to a pressure system like glo.

Thanks for the idea
Bob

propchief

My Feedback: (65)

On the first tank the fill goes to the engine and the vent line to the fill on the second tank. That way as the fuel is drawn from the first tank it sucks fuel from the second tank. Don't have a diagram handy, but hope this helps.

bob_nj

My Feedback: (62)

I know that works with glo where the tank is pressurized, but will it work with gas where there is a draw, and not pressure?

It seems that the I would be drawing through an open vent.


Thanks
Bob

JoeAirPort

My Feedback: (41)

The issue is will the engine pump have enough power to be able to draw from two tanks? You would always be drawing from a clunk. Only one vent is open to atmosphere, the 2nd tank. And it needs to be for the fuel flow to happen. The fuel will always be drawn from the clunks. The vent in the 1st tank would be dripping fuel into the 1st tank that is sucked from the 2nd tank. I would think that the 1st tank would get emptied before the 2nd tank filled it due to there being more suction in the 1st tank. Interesting question.

PS: This would be cool to try on an engine stand.

juanes1969

The walbro carbs have enough power to pump gas from 3 feet away, however, the vent line coming from the second tank to the main tank( the one that will fill the main tank up) can make it a little more difficult for the carb to pump normally. So what you can do is to install one tank on top of the other. Main tank on bottom, secondary tank on top, that way the gravity will help the carb to fill the main one. Now, if the plane is an aerobatic one, that installation could backfire on the carb (maybe) and make it more difficult when inverted or other maneuvers.
One tank behind the other (main in back and secondary in front) will help in an aerobatic airplane with a direct line fron the main (back) tank to the carb and the vent line on the secondary filling the main one.
I have tried both ways with success in a 33% YAK, just to see how long I could keep it flying.
Hope this helps,
John

bzrogers

My Feedback: (7)

I have friends that forgot to pull the plug out of the vent line. His DA-150 ran fine the whole flight and after he landed the tank had completely sucked in.

I think most (good) engines will have enough suction to draw from two tanks!

The other option would be to run a "T" and send one line to each tank. Then their would be two vent lines and two lines connecting to a single line that runs to the carb.

Just my two cents, take it for what it is worth.

Cheers
BZR

David Jackson

My Feedback: (15)

I use two tanks on my DA 150 powered 40% Yak 54. The main tank is a 50oz tank with the vent line attached to a 24 oz tank. I have never had a problem with fuel to the engine. I usually fly for approximately 8 minute each flight and I've discovered there is no need to carry 74 oz of fuel. If I remember correctly, the DA 150 will burn 3oz of fuel a minute at full throttle. So depending on the size engine you are using, and unless you are planning to fly for long periods time, 20 minutes or more each flight, a single 50 0z tank should provide more than enough fuel. [8D]

bob_nj

My Feedback: (62)

Good stuff guys.
This is for a project at work, and non aerobatic.

Thanks for all the insight
Bob

yarom

My Feedback: (82)

Does not sound good. If one of them empties before the other, that clunk would be sucking on air. The mixture getting to the engine through the T fitting would make it lean...

JoeAirPort

My Feedback: (41)

They should empty at close enough to the same rate. Then you would just time it like with a single tank (but probably a longer time).

rc bugman

My Feedback: (30)

Hi,

Multiple tanks on gassers work the same as glow.

Tank 1. Clunk line to engine, vent attached to the clunk line of tank 2

Tank 2. clunk line to vent of tank 1 and vent to tank 3 or atmosphere.

As the quantity of fuel increases with multiple tanks, it helps to have the additional tanks along the center line of the carb so the pump does not have to "suck" up hill. I have been using this tank hookup on research planes for many years and some times the multiple tanks are gallon containers.

Hope this helps

Elson

bob_nj

My Feedback: (62)

Thanks bugman, that's helpful.

I can't get my head around how the vent from tank one can suck fuel from tank 2.
It just seems like it's sucking air if it's through a vent?

Take care
Bob

Rcpilot

My Feedback: (78)

Here ya go Bob NJ:

rc bugman

My Feedback: (30)

bob

Just think of a siphon. Once the flow of fuel is started, there is a continous column of fuel from the front tank all the way to the rear tank whether it is 2 tanks in the chain or 10 tanks in the chain. However, if there is an air leak in the system, only the tanks between the air leak and the carb will empty. Tanks beyond the air leak will remain full. So, an air tight system is important.

I often use screw top tanks in my larger research planes so I can fill the tanks like a lawnmower. In these situations, it is important that the caps are tightened down tight after filling. Otherwise, the entire fuel supply is not used and the planes run out of gas before they are supposed to.

Hope this helps

Elson