this. High pressure pumps need to be either in the tank or immediately
below or beside the tank because they don't suck well or tolerate
bubbles well. I think that any of the injected Soobs could be run
returnless. Just put the pressure regulator in or beside the tank and
perhaps insulate the fuel rails. That's the way some or all of the Neons
do it. I don't consider it a problem to route high pressure fuel through
the cockpit but it is nice if the ecm shuts off the fuel after an engine
stoppage. They all do that if wired like the car. But then we often add
a second pump for takeoff and landing that will stay running (or in some
cases start running) after an engine stoppage...
With a header tank you can plumb low pressure gravity fed fuel into it.
Put the header forward of the firewall and then all the high pressure
fuel is out of the cockpit. Sounds attractive at first glance but then
perhaps the header fuel is in one of the worst places if there is a leak
or rupture in an accident. A small tank can be fairly robust and should
probably be mounted like in a car. No welded tabs to crack or break off
and leak. Just put a couple of bands around it. Assume the surrounding
structure will be deformed in an accident and leave room for the hoses
to flex and move a bit without being ripped off.
I'm also reminded of a statistic that Bob Knockoll's has mentioned. It
seems that there is seldom a post impact fire in light aircraft if the
battery is ejected by the impact. Battery ejection might be a tricky
design objective but it does seem wise to try and keep fuel away from
the electrics which are probably the most likely ignition source.
Happy New Year to all...
Ken
Bob Patterson wrote:
To each his own .... I've always disliked header tanks, ever
since I lost a good friend who was burned in a Super Cub crash
because the header tank split & sprayed gas all over him & the
burning engine ...
I know you did a lot of work to crash-proof yours, and I think
it's mounted in back, instead of on the firewall like the Cub,
but to me it's still extra work, & an added hazard, and besides,
I'm all in favour of "active fuel management" ;-) --- often
the lack of attention to the fuel status is what causes a lot
of silence, and an instant glider, at inconvenient times ! ;-) :-)
"Returnless EFI" - now THAT sounds like the ideal answer !!
It would be great if Subaru went that way !
......bobp
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