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.
Hi Mike,
Another option for the lines instead of floxing them is to put a pipe
fitting into the tank as required. You can get bore through fittings
from Swagelok.
These do not have the smaller bore down from the nut and ferrule area
that stops the tube from going farther through. If you put a 3/4" NPT
fitting in the tank, you can put a suction screen on a tube and have the
tube bent to where you need the end at. Then you slip the fitting over
the tube and tighten the fitting in. Once the fitting(tube adapter in
Swagelok speak) is tight, you tighten the tube nut to lock the tube in
place. Then you can cut the tube off an inch from the nut and can then
use a tube union to connect to it.
There is
also available reducing unions. An example of the part number for these
is; SS-810-6-6. This would connect a 3/8" tube to a 1/2" tube.
Also there is Alloy fittings for different applications to deal with
some chemicals. Some of these may be lighter, but also more costly. Once
you finalize the fittings required you can contact the local Swagelok
people and compare the costs. I do not think the weight savings would be
a lot, but a kitchen scale would answer that quickly.
The fitting to put in the tanks are readily available for welding into
pipe or thin wall tanks made of sheet metal. Known as weld-o-let. To
flox, protect the threads and use a course sand blast to rough up the
surface. Fiberglass tanks use this method and have 2" to 4" fittings
with no problem. Grounding cables are commonly attached here also as a
stud can be welded to the fitting before glassing that the ground can be
attached on to. Very common in the oil patch for produced tanks to catch
water. Of course there is always some hydrocarbons with the water that
could ignite with a static build up.
Dale Davies
Thanks for keeping me straight Dale. I made the changes to the TA-1-X
fittings. I also added a grounding cable, Thanks for mentioning that I
didn’t even think of it for the sump. I'm also going to think about
just making the sump out of Al and then I could just use the -810-1-12W,
-1210-1-12W and -400-1-4W. I think it would be easy to cut out the
pieces but I don’t have a Tig so I would have to go find someone who
could weld it all up for me... it would also make grounding easier.
Anyway, Attached is an updated diagram for you guys to throw more darts
at. Thanks for all your help.
Mike C.
The 3D postion of the parts is also important.
Paul Lamart
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