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Hi
Guy's;
I'm looking for a small, compact fuel cooler of some sort. I tried Google, but
get a ton of listings for ******partstore.com, but none of them actually lead to
any fuel coolers. I did find one other but it was for a fairly large cooler
(12"x3"). I was hoping for something closer to 3"x4". I've been monitoring the
firewall temp at the location of my fuel pumps and filters (on the cool side of
the engine) and it is consistently around 60C, while doing touch & goes. I'm
considering putting a tee in my return line to install a temp sensor to measure
fuel temp before it returns to the header tank as I suspect that it is
considerably warmer than this, due to heat from the turbo charger, which is in
fairly close proximity to the injection rail.
During extended touch and goes, the turbocharger is producing full power every
few minutes and I've began to use both boost pumps while in the circuit. this
combination seems to contribute to a build up of vapour in the header
tank. I also keep the boost pump on to keep the header tank pressurized to
7psi to help counter the vapour issue.
A
few days ago, after an hour of touch and goes, the vapour press apparently built
to 7psi and during my pre-landing checks while on downwind for runway 33, I
found that one of the FI pumps had just begun to cavitate indicating
vapour-lock. I immediately switched on both boost pumps, but the second boost
pump began to cavitate also, followed shortly after by that eerie silence that
we all hate. I immediately began to vent the pressure off the header tank while
continuing to pump to it, and set-up for a dead-stick landing onto 24. Landing
was uneventful and restart was easy as soon as the excess vapour pressure was
vented from the header tank.
I
understand the conditions that contributed to this, and it can be overcome by
venting build-up pressure on a timed basis, but I prefer to keep the header tank
as a closed system while in-flight. I realize the Ed is the only one who is
flying with a similar system using a header tank. Ed, if IRCC you had similar
problems with vapour lock before you switched to Avgas?
Now many of you will suggest that I just switch to Avgas, but that is not an
affordable option for me. The price difference here is so horrendous as to make
the difference between whether I can afford to fly or not. Of course I'm not
willing to risk continued vapour problems to save money either, but rather try
to find an affordable solution that will safely solve the
problem.
My current plan is to shroud the fuel pumps and filter to isolate them from the
cowl heat and duct a 2" hose from a NACA duct like the ones used for ventilation
on an RV (and probably many others) to this shroud, but have the air pass
through a small fuel cooler located at the air inlet to the shroud. Exit air
from the shroud would have its own exit out the bottom of the
cowl.
So my question for the list is does anybody know of a source for an
off-the-shelf compact fuel cooler? Any other suggestions would also be
appreciated. While I've considered the option of doing away with the header
tank, at this point I'd like to try to keep it as it does have advantages for
managing 6 fuel tanks.
Ps.... This
really isn't as bad as it sounds... really :-)
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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