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Due to my addition
of auxiliary fuel tanks, I installed a header tank to return fuel to. After
reading Ed's chronicles of his tank and exchanging a few e-mails with him, I
decided to build a tank large enough to provide a usable reserve and locate it
aft of the firewall. I had concluded that the larger fuel volume and cooler
location would preclude the percolation problems that Ed has
experienced.
Well it seems that most of the heat is picked up as the fuel runs through
the system, as I'm seeing some signs of heated fuel. It has been warm here
(30C+) and problems didn't start showing up until after extended taxi runs
(40min), but I'm trying to take care of worst case scenario. Turning on a boost
pump does help, but I don't want to have to run one continuously. I'm hoping
this will not be necessary while in-flight.
I
did equip this header tank with a vent valve to purge the air out before
starting engine. This valve would normally never be open during operation as I
expected the tank to be under a vacuum as it draws fuel up from wing tanks, but
when I did crack it open, I was surprised to see it was under pressure. If this
continuous, I may add a press gauge to monitor this.
S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".
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