Hi All, It?s been a while since I?ve been on the newsletter between
work and trying to make progress on the Long EZ. Anyway, it?s
time
for the Fuel system and I wanted to get feedback from the group on
my design. I attached a PDF of my concept which utilizes 2
different sumps, 1 rear cockpit thigh support/fuel sump and a 2nd
sump in the hell Hole. The reason for the added sumps is to
try to
recover some of the fuel I will be losing due to installing
Infinity
retractable gear. Anyway, my assumption was a P-Ported 13B
with a
TO4 turbo so the lines need to be able to keep that thirsty puppy
humming at WOT. I guess it would make about 350hp at WOT.
Anyway,
can you guys take a look and shoot holes and make recommendations.
I look at the fuel system and Engine installation design as the
most critical systems we develop so I want it to be right.
Thanks
Mike C.
I'd put a fuel drain in the lowest part of each sump where lowest is
when the ship is parked.
I'd put the pumps in the last sump.
I don't see provision for fuel return.
tc
--
Thanks TC, cant believe I forgot the return line. I decided to do
away with the Hell hole sump, seems like I would be creating a lot of
work for little gain. I did add a fitting to the thigh sump so I
could add an Aux Tank if it was ever needed. Could just strap it into
the GIB seat. Anyway, I have a couple of questions about the fuel
return. Will it have enough pressure to overcome the head pressure in
the sumps from the Strake tanks? And the thigh sump is probably only
2-3 Gallons so should I be worried about hot fuel in the sump? Or
should I just return the fuel to the strakes? If I return it to the
strakes is there a chance I could empty the sump faster than the
gravity fill line can return it to the sump? Thanks again for all the
help guys. I attached an updated diagram, throw arrows!
Mike C.
Paul
I'm resending this because I never saw it posted, Might
have gotten lost in the ether.
Thanks
Mike C.
the return lines need to return to the tank or sump from which the
fuel was removed . Summer time heat increases the risk of vapor lock
when fuel is returned to the sump. Better to return the fuel to the
strake tanks. The sumps/tanks should be separate and feed of fuel is
from one or the other NOT BOTH SIMETANEOUSLY. Cross feed will occur
and will drain the tanks. See the write up on Central States Canard
News Letter. The vent to air line can be a 1/4" line with no problems.
Andair makes a valve which makes the selection of feed and return fuel
easy. Putting the sump tanks behind the front seat as a foot rest for
the passenger is a possibility. However fuel is then in the cockpit.
Chris Smale
Hi Chris
I'll make the change to reduce the vent line to 1/4" and I'm
planning on using the Andair
Fuel valve. I did read the central States Canard News letter
outlining the cross feed issue
And have no plan of cross tying the left and right sides together
except through the fuel selector
Valve. For the fuel return line I currently have it t-ing into the
fuel sump which is basically two individual
cells (Left and Right) and a little over a gallon in each side. I do
have concerns about fuel temperature
in such a small tank and would rather return it to the strakes but
there are issues with that as well.
If I return the fuel to the strakes how do I split it so that I'm not
returning it all to one strake? The other
concern I have is running the sump dry. Can a 5/8th gravity feed to
the sump keep up with the
engine and the loss Of the return line fuel at WOT? I guess I could
go bigger on the fuel line from the
Strake to sump maybe a 1" line but that's getting pretty big and I
would still have the same question, is 1"
adequate? If I return it to the strake how hot will it get? If I
decide the right thing to do is return it to the
stakes how do I return it to the proper strake? Does the Andair have
provisions for fuel return? What happens
when you have "Both" selected on the fuel selector, How do you ensure
the fuel returns to the proper tank. I could T
the return lines back to both strake tanks like I have it set up now
for the sumps but that would cause asymmetrical
fuel loading if I select either the Left or Right independently. Ideas?
Thanks
Mike C.
Andair makes a fuel valve which is 2 separate valves on one shaft. It
can be setup so that fuel return goes back to the source tank.
The fuel valve should not have a Both only right or left. Or you can
block off the both input and output , however this leaves you the
possibility selecting both with NO fuel going to the engine- not good.
A 3/4" fuel line from tank to sump is more than large enough as long as
you have a 1/4 or 3/8 vent line going from the sump to the strake tank
ends of the vent lines should be in the air spaces at the top of the tanks.
chris smale
Thanks Chris, I looked up the ANDAIR Duplex valve and made the changes
to the system. I also, modified the vent lines from the Sump so they
connect to the Each Strake.
Thanks
Mike C.
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