can i install a header tank laying flat on it side? will it have issues?

No, not really... The whole point of the header tank is to keep bubbles from getting in your fuel line... Your normal "tank" has a regular clunk in it... That is, it's designed to "drain" the tank since the clunk reaches all the way back and into the bottom of the tank... The problem with this arrangement is that during hard 3D it's easy for the clunk to get slung OUT of the fuel for a moment... This allows air bubbles in your fuel line... That's a VERY bad thing on a heli...

In comes the header tank... The PROPER way to have the clunk in a header tank (and I can't TELL you the number of people I've seen do it incorrectly) is to have the line cut so that the clunk stays basically right in the CENTER of the tank... I've seen a lot set it up just like the fuel tank, with longer line to allow it to reach the bottom back of the header tank too... Problem is, it negates the purpose of the header tank, since in this arrangement the clunk can get slung out of the fuel just like the main tank... With the clunk staying right in the middle of the tank, first, it's stiffer, so it basically stays in place during hard 3D.... Now think about the physics behind it... If you take a jug of water and start flipping it back and forth and all over, where do the bubbles stay? On the outside of the container... Always on the opposite side of gravity.. That means the clunk in the center of the tank always has a nice bubble free supply of fuel.... Any air the main tank picks up during maneuvers gets drawn into the header tank and never gets picked up by that clunk...

Back to your issue, because of WHAT the header tank does, if you install it flat on it's side, first, the clunk will (due to gravity) most likely be able to fall to either top or bottom easily... Thus, it will again be able to "reach" where bubbles are and suck air...

Just curious... What's this going into??? I've never seen a bird where it would have been easier to mount a header tank flat rather than vertical anyway???

Sure, the header tank is always full, it doesn't matter how you install it, as long as the clunk can move in it freely. If you run the main down all the way and get into the header fuel, you just have to make sure you don't get it low enough to start sucking air. there should be no air in the header when you are flying to suck bubbles. Thats the purpose of a header tank.

AS stated above, the clunk should sit more toward the middle, but I still have mine back quite a ways, not exactly in the center. I like to get most of the fuel out when I de-fuel.

http://www.rcuniverse.com/forum/m_28...tm.htm#2841603

Just found this thread, and read through it. Go look at it. Its all been hashed out and everyone has good points. You can make your choice from that instead of making them all hash it out again.

Make your decision from it.

I don't know why you would want to lay it on its side, but I still think it would work as stated. Thats just my opinion. Haven't tried it.

I often run a header with no clunk, just a short bit of tube. Like they say, we try to keep the header full so no air means no froth but without the clunk you have to be aware when the main tank is empty.