Gas tank question

[Colin Broughton]

I noticed in some of the photos posted that some birds have a little tank on the side of the stock tank. Why its this and should mine have one too?

[pilot4fn]

Originally Posted by Buildmagazine

I noticed in some of the photos posted that some birds have a little tank on the side of the stock tank. Why its this and should mine have one too?

That is called 'header tank'. Main reason for it is to provide bubbless fuel to the engine during 3D flying. Second reason is to provide reserve fuel when main tank is dry.

Normal sport flying, You don't need it. Also, 'fuel magnet' does the same trick on sucking every last drop of fuel from main tank without bubbles.

[Zaneman007]

I put header tanks on all my helis. I like to run the main tank dry, dry, dry.

In addition, you don't have to worry about not getting fuel when your doing nose down tic tocs on a 1/4 tank or less of fuel.

They were stock parts on the old Raptor 50's. And some of us old farts, liked them enough to put them on our new helis.

[pilot4fn]

I'm running original clunk on main tank with stock header tank.
When main tank has only 30% or less fuel left and I'm doing flips or rolls (etc), engine goes lean pretty much every time for a moment.
Should I toss the header tank and get Lynx Fuelmagnet or how can I get rid of this annoying engine running too lean for 3-5 seconds?

[Cra-Z-1]

Originally Posted by pilot4fn

I'm running original clunk on main tank with stock header tank.
When main tank has only 30% or less fuel left and I'm doing flips or rolls (etc), engine goes lean pretty much every time for a moment.
Should I toss the header tank and get Lynx Fuelmagnet or how can I get rid of this annoying engine running too lean for 3-5 seconds?

That is EXACTLY what was happening with my 600N and header tank even "with" fuel magnet. It wasnt until my fly bud finally convinced me to drop the header tank, that all my issues went away. I was seeing engine hesitations during nose down flips and loops to inverted every single time, until I ridded my heli of it. I enjoyed the extra fuel, but quickly adapted when I seen the result of removing it.

I think that the problem lies in the clunk in the header tank. The tanks are so skinny, that they dont allow the clunk to bend around to pick up fuel. If you nose down, and have any kind of air in the tank, then probably your clunk is going to be out of the fuel for a moment. Anywho...thats my experience., I wouldnt go back to a header tank.

The Fuel Magnet is awesome!

[pilot4fn]

Originally Posted by Cra-Z-1

That is EXACTLY what was happening with my 600N and header tank even "with" fuel magnet. It wasnt until my fly bud finally convinced me to drop the header tank, that all my issues went away. I was seeing engine hesitations during nose down flips and loops to inverted every single time, until I ridded my heli of it. I enjoyed the extra fuel, but quickly adapted when I seen the result of removing it.

I think that the problem lies in the clunk in the header tank. The tanks are so skinny, that they dont allow the clunk to bend around to pick up fuel. If you nose down, and have any kind of air in the tank, then probably your clunk is going to be out of the fuel for a moment. Anywho...thats my experience., I wouldnt go back to a header tank.

The Fuel Magnet is awesome!

I'll order one today, so I can take a test flights on it next weekend.
Thanks for help.

[Stevendavis]

I run a header tank on my 600 and 700 on non regulated engines. I think its less critical on regulated engines like the YS, and OS-HZR. Mine run better with the header tank. One thing that you need to check with a new header tank is the vent nipple. Most of the ones I've used needed to be re-drilled to open the passage when they are new. Same with the main tank vent nipple.

[Zaneman007]

If you have a header tank and it's not working, you could have an air leak.

[pilot4fn]

Ok. I'll check the header tank nipple for need to open it a bit.
Also, if there will be air leaks - latter which I do not know if it will make difference.

[chosen69]

Originally Posted by Cra-Z-1

That is EXACTLY what was happening with my 600N and header tank even "with" fuel magnet. It wasnt until my fly bud finally convinced me to drop the header tank, that all my issues went away. I was seeing engine hesitations during nose down flips and loops to inverted every single time, until I ridded my heli of it. I enjoyed the extra fuel, but quickly adapted when I seen the result of removing it.

I think that the problem lies in the clunk in the header tank. The tanks are so skinny, that they dont allow the clunk to bend around to pick up fuel. If you nose down, and have any kind of air in the tank, then probably your clunk is going to be out of the fuel for a moment. Anywho...thats my experience., I wouldnt go back to a header tank.

That doesn't make sense, the whole reason for the header tank is to stay full all the time.

[michael503]

Originally Posted by chosen69

That doesn't make sense, the whole reason for the header tank is to stay full all the time.

Yeah, if you're getting air in the HT and the main tank has between 1/4 and 1/2 tank, you may have an air leak on the main tank pickup line.
I have a HT and have never had this issue.. but I don't do nose down tic tocs yet

[pilot4fn]

Originally Posted by michael503

Yeah, if you're getting air in the HT and the main tank has between 1/4 and 1/2 tank, you may have an air leak on the main tank pickup line.
I have a HT and have never had this issue.. but I don't do nose down tic tocs yet

Issue appears when main tank has 1/3 or less fuel left. As I land, there is air in header tank maybe amount of a teaspoon. Many times during flight, I come close to check fuel level and never see any air in header tank until main tank has only 1/4 or so left.

I thought this to be pretty weird as well, but change is done and I'll see what happens with fuelmagnet (and w/o headertank) tomorrow.

[Zaneman007]

What you are describing is not weird. If you have a hole in the fuel line, it looks good until you get to the hole. The fact that it is consistent screams air leak.

I hope you replaced the fuel line in the tank. You do not have to be able to visually see the hole in the fuel line to have an air leak.

It is good you have a header tank to keep the engine from leaning out.

[pilot4fn]

Originally Posted by Zaneman007

What you are describing is not weird. If you have a hole in the fuel line, it looks good until you get to the hole. The fact that it is consistent screams air leak.

I hope you replaced the fuel line in the tank. You do not have to be able to visually see the hole in the fuel line to have an air leak.

It is good you have a header tank to keep the engine from leaning out.

I took the bird in air on Sunday w/o header tank but with fuel magnet. And exacly same issue happens. Engine leaning out for few seconds after flip, roll etc when less than 1/4 tank is left.
Clunk line was only 2 months old and I also put a fresh one in last friday with fuelmagnet?

Could there be air leak on the nipple where clunk line attaches to exit the tank? This one I did not inspect yet - or what in the world causes this

My frends are flying their tanks bone dry with fuel magnet while not having any issue on engine leaning out.

[drdrums]

Guy was having problems with inconsistent fuel delivery to his YS120 on his 700 Nitro. His solution was to use a latex balloon inside the tank as a fuel bladder - took a length of tubing, punctured some holes in it along ts length, and secured it inside the ballon, then secured the assembly into the tank. Voila, consistent fuel flow regardless of orientation or tank level.

[Stevendavis]

If you decide to put the header tank back on, try to get the center of the header tank as close to the centerline of the carb as possible.

[stephenwagner]

Is your clunck line too long and getting stuck on the back wall of the tank after a flip?


SJW

[Zaneman007]

Clunk line was only 2 months old

Doesn't matter, besides the cost is nothing compared to a blown engine caused by overheating.

Places to check for air leaks:

Fuel lines, internal and external
Grommets that seal the tank
Loose muffler
The tank itself

I hope you figure it out.

[pilot4fn]

Originally Posted by Zaneman007

Doesn't matter, besides the cost is nothing compared to a blown engine caused by overheating.

Places to check for air leaks:

Fuel lines, internal and external
Grommets that seal the tank
Loose muffler
The tank itself

I hope you figure it out.

Yesterday I removed the fuelmagnet and clunkline. Chcked that all connection points looks to be without blemishes - put everything back and... It works! No more running too lean after flips etc.
What did I do to fix it... idunno

[Zaneman007]

It could have been the grommet that connects to the fuel line and seals the tank. You may have reset it when you reinstalled it.

I replace an OS50 with a YS56, just to find out that I had multiple air leaks, and the grommet was one of them. Once the YS pressurizes the tank, the leaks show up as slow fuel drips.

Makes me wonder how many times my "engine" problems were due to undetected leaks.