Originally Posted by S3NFO

Your theory is great Dar, but my practical application from dozens of glow DF jets beats your theory every time. As long as the fuel line from the tanks to the T's is the same length, I've never, ever had a problem with one tank running dry while the other still had fuel.
I'd bet there are several thousand old school DF guys out there who've run 2 saddle tanks in parallel with no problems.

S3NFO,


So, are you saying your way is trying everything on your own???

"So, that other guy died from jumping off the roof... I'm sure I will survive it. I'm jumping off now!"

What theory predicts can happen, eventually will happen.
I don't know if the fuel-tanks in your DF jets are visible from the outside, but can you still tell me if you ever observed, immediately after landing, a noticeable difference in fuel-level between them?

Immediately, because the physical 'law of connected vessels' will equalize the levels within a few seconds.

The only possibility for one tank (or one side of the saddle) to deplete itself earlier, is if gravity perceives its bottom as being higher than that of its counterpart...

...Which can happen as a result of various issues that I mentioned in my previous posts.

Originally Posted by epoxyearl

The solution,in my case is NOT a single tank....I want the extra fuel that only two tanks can provide..
I watched a video recently of a pattern plane with a clear tank mounted outside the airplane.....at times the fuel was suspended at the top of the tank in level upright flight. There was fuel movement the entire flight. At time the pickup was uncovered and the engine continued to run,from the fuel in the lines. It was immediately replaced by muffler pressure when the clunk became resubmerged.

You did understand that I'm using muffler pressure to the single vent, and it's a 4 stroke, with excellent fuel draw, correct?

Engine connected to tank "A", vent line of tank "A" connected to tank "B" clunk line, tank "B" vent connected to muffler pressure.

Mount the tanks beside each other on the same level.

Throw out the bad advise, implement the good, We laid down the drawings for the recessed engine mount and twin fuel tanks...It's a GO!

Originally Posted by DarZeelon

S3NFO,


So, are you saying your way is trying everything on your own???

"So, that other guy died from jumping off the roof... I'm sure I will survive it. I'm jumping off now!"

What theory predicts can happen, eventually will happen.
I don't know if the fuel-tanks in your DF jets are visible from the outside, but can you still tell me if you ever observed, immediately after landing, a noticeable difference in fuel-level between them?

Immediately, because the physical 'law of connected vessels' will equalize the levels within a few seconds.

The only possibility for one tank (or one side of the saddle) to deplete itself earlier, is if gravity perceives its bottom as being higher than that of its counterpart...

...Which can happen as a result of various issues that I mentioned in my previous posts.

Noooo, I'm saying that 1,000 glow DF guys before me used parallel tanks and I benefited from their experience, and that 10 years of practical application from never having a dead stick from fuel starvation "should" be worth something. Serial tanks are definately easier, and all I use on turbine, but parallel tanks works fine.

May I suggest one other possible solution?

Plumb the tanks in series.

The line from the clunk in tank one goes to the vent line in tank two.
The line from the clunk in tank two goes to the engine.
The pressure line off the muffler goes to the vent line on tank one.

As the engine draws fuel from tank two the exhaust pressure pushes the fuel in tank one to tank two. Tank one goes empty and the pressure just passes through to the top of the fuel surface in tank two until depleated.

No problems with sucking air from either tank.

MTC YMMV

Originally Posted by Majortomski

May I suggest one other possible solution?

Plumb the tanks in series.

The line from the clunk in tank one goes to the vent line in tank two.
The line from the clunk in tank two goes to the engine.
The pressure line off the muffler goes to the vent line on tank one.

As the engine draws fuel from tank two the exhaust pressure pushes the fuel in tank one to tank two. Tank one goes empty and the pressure just passes through to the top of the fuel surface in tank two until depleated.

No problems with sucking air from either tank.

MTC YMMV

I believ the OP has already determined that is the way he is going to go.