freestyle
Veteran
Location: Redmond WA USA
| Answer: it dependsI don't use a header on my Intrepid 3D, but I think this is made possible by two things: first, I use a YS ST2, and they seem to be pretty tolerant about air bubbles; second, I chose my fuel tank installation carefully.
I use a 16oz Nalgene fuel tank, like what Furies and some XLs use (and maybe some Bergens?). The fuel fittings are installed in the cap, for maximum clunk freedom (i.e. you get long clunk lines this way). The tank is also installed with the cap facing to the rear and the longer side vertical (rather than horizontal as with the Fury), so if there's fuel in the tank it will pools fairly deep. Dunno about other helis, but vertical installation is very on the 3D if you remove the push-pull tail rotor bellcrank, which I don't think is very helpful anyhow. Finally, I'm using a Robbe felt clunk, which all by itself does a pretty good job of stopping air bubbles.
This setup is good to the last drop, even without a header. I have run it down to just a trace of fuel in the tank, though I did keep it upright for the last minute or two just to be safe. 
My Futura never used a header when the YS was in that motor, but when I switched to OS in that heli I put on header tank. I keep meaning to take off the header just to see if it's really necessary, but I haven't done that yet. That Robbe clunk is great, and it might be enough all by itself. The Futura tank ain't bad, but I don't think it's quite as good as the Nalgene tank in my Intrepid 3D. |
