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.
Now you are talking my language as an instrument tech (industrial).
Why use
cad plated carbon steel fittings. This is designated by the single S
prefix. I would use either SS (stainless) there is a a couple of
different stainless types available or alloy. Also a couple of
options. Use the SS ferrule sets.
With time the cadmium plating seems to let the nut stick to the
fitting and it takes some effort to break it loose. SS does not have
the same problem. Its problem lies with a lack of tolerance to cross
threading. Proper tightening of the fittings is important. Start
with the nut just finger tight on the fitting and then tighten 1 1/4
turns. Use a felt pen to mark it to get it right.
Also, I would use 1/2" return line to make sure there is no
restriction there.
What is the method of connecting to the sumps. You show tube unions
(600-6)
with the tube coming out of the sump. Another fitting available is
SS-6-TA-1-?
i Left a question mark for the pipe thread size; 1/4,3/8, or
1/2"NPT. These would be 4, 6, or 8 like AN designations. This would
then allow the use of the tube unions directly. A better option is
SS-600-1-? tube adapter. If you need a 90* then SS-600-2-?. There is
also 45* available. This would eliminate a possible leak source or
two. You know every joint will leak eventually.
Swagelok has available a small catalogue that is about 6" x 3"
and about 3/8"
thick that lists a lot of this and explains the codes for it's fittings.
Also
pressure ratings for tubing sizes and materials.
Dale
Hi Dale
Thanks for the info, I only chose the Steel because they were a
lot cheaper, I'll change to SS. I will also increase the size of
the return line to 1/2". My plan is to use Al tubing which will be
floxed into the sumps and Swagelok fittings to connect the lines toe
the stub tubes in the sump. It seemed like a simple solution. I
did look at the Swagelok fittings with NTP -600-2 on one end but
thought if I used Al tubing I could bend the tubes in the sump to
the location (lowest point for the fuel feed and highest point for
the fuel supply and vent) that they needed to be at. Then flox them
in place through the sump walls with a stub tub protruding which
will allow me to use a union to attach to the rest of the supply
lines and vents. Now that I think about it I could use a ss-600-2-8
for the return lines and a SS-600-2-12 for the Sump feed and
increase the feed line size to 3/4". Then use the original plan for
the fuel pick up lines to the Andair valve. Keep shooting arrows,
I really want a bullet proof Fuel System. No fuel = no thrust =
BAD DAY!
Thanks
Mike C.
I made all the suggested changes to the fuel system. Here is the
latest design. Still need to figure out the return... To the sump
or the strakes? Thanks for the help guys.
Mike C.
I was told by a very knowledgeable person who installs jet engines in
Cozys that 5/8 inch fuel lines would be best for fuel systems
feeding 300+ hp engines. All your other ideas appear to be on the mark.
Hope this helps.
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