----- Original Message -----
Sent: Sunday, September 02, 2007 1:37
PM
Subject: [FlyRotary] Re: need help
Hi Joe,
again the "customary" :) up front!
1-2 gallons is a lot of space for a lot of
trash! If you have the need for that much space you
need to change your fuel supplier right now - or
redo your fuel system!
A small 1-qt sump is really all you need.
What you should get though, is an easy access to a
huge drain (high volume flow) on that sump
and use it every chance you get - like after every
refill, before every flight, after any time in a rain, every time you only
"visit" your mistress!
That does:
a) Avoid that anything settles/sticks to the sump-bottom
b) Doesn't let any accumulation of debris happen
c) Tells you what is going on in your fuel system
If the drain samples are clean put them back in and be happy that you
have a clean fuel system! If there is some water in there, separate the water
and use the fuel again.
In any system that uses a sump and or gascolator, I
would (the customary...) make sure that the supplying tanks
do not have a sump for debris control, but for fuel
collection only.
If you use your main sump drain often there is no way you ever will
accumulate a lot of debris.
Condensed water is not a contaminant, but a normal occurrence. It only
becomes a problem if you leave it in the sump for ever and it becomes the
nourishment for fungus....
As a matter of fact.
E.g. the Robinson helicopters have 2 tanks with a drain each, join the
fuel lines and pass through a gascolator before going to the engine.
When ever I saw an increase of "flotsam" in the drain samples, I would
close the fuel-shutoff (before the gascolator....) and pour about 1/2 qt of
clean water into the tank!
Whoever saw this would freak out!!
What does that: It lifts any debris that would sink in gasoline, but
float in water of the ground and keep it on top of the water.
Now I would drain the water - make sure you never stop draining until you
see pure gasoline running out. All the mud would be floating like a black disc
between the water and fuel in the drain bottle...
Before flight rock the wings, taxi on a slight sloe both ways and drain
the sumps again - ready!
Whatever rest (water) stays in the will go to the bottom of that 1-2 qt
sump. Any rest is way less than what you get with 1/2 full tanks and weeks of
parking in "condensing conditions"....
I prefer to get any muck out of the wings as soon as possible into a
place where it can get drained quickly...
At my job (flying helos for a living....) I would drain before every
flight, even if the mechanic just pulled a sample 5min ago after
refueling...
Best Regards,
TJ
On 9/1/07, Joe Ewen
<Jewen@comporium.net>
wrote:
Hi Wendell,
I would agree with Thomas (including his
customary warning.) I would add one item to consider. I am
building a Velocity and am positioning the fuel supply from the sump
(hopper) tank a couple of inches from the bottom . The idea is to
leave 1 to 2 gallons in the sump as an area for water and contaminants to
settle. One might argue that the 1 or 2 gallons may be helpful if low
on fuel, but I plan (hope) on never operating the AC that low on fuel ( i.e.
John Denver.)
Joe
----- Original Message -----
Sent: Friday, August 31, 2007 11:05
PM
Subject: [FlyRotary] Re: need
help
Hey Wendell,
now up front my customary warning:
All I post is copied/theory/"what I would do"/no personal experience
- worth what you paid for!
b) Okay, it's the little brother (or actually daddy?), but the
systems should be similar?
c) With reference to the article above, I would make a 5--8 gallon
alu or plastic tank, somewhere below the wing level - under the rear
seats as Bill's system or if you don't like the idea, at the lowest part
behind the firewall, but somewhere where the mains can drain into easily,
1/2" lines.
I always promote "heavy" fuel lines, never less than 1/2", helps a
lot to prevent vaporlock, air bubble lock - after running the tanks dry.
An air bubble will have a hard time to block a 1/2" line...
I'd prefer alu for the tank, as it is easier to do fuel plumbing,
like in-tank fuel pumps.
Obviously the Cozy (or most Canards) are not real low wing aircraft,
but rather midwings, so creating a system that can drain into one common
sump should be possible.
Make the tank round or V-shaped at the bottom and you should be able
to run it nearly dry (less then 1 gal unusable...).
d) If you copy Bill's system you only need 2 shut-offs, that stay
open except for maintenance purpose and 1 single shut-off at the
firewall.
e) Return to the 5-8 gal header/sump should keep the temps in control
or if you prefer to anyone of the wingtanks, as they are normally open and
connected it will balance fine until very low - then watch the ball! FLy a
little left/right to empty the wingtanks and land on the 5-8 in the sump!
:)
f) One difference I would make is to lead ALL ventlines into one
common manifold at the highest point possible (behind the rear seat
headrests or just behind there on the firewall) and vent this manifold to
some static area (mainwheel fairing?). Just make sure your filler caps are
airtight.
g) This way you only need 2 fuel pumps in parallel - you are truly
redundant, no fussing around with fuel-selectors (except for
after shutdown, if you care for - as your engine is at or above the
general fuel level, there should be no real reason to shut off fuel every
time....)
Best Regards,
TJ
On 8/30/07, Wendell
Voto <jwvoto@itlnet.net>
wrote:
Subject: [FlyRotary] Re: need help
TJ,
Sorry about the delay in responding, have been away doing my
contract work (still a necessity). I am building a Cozy. Bought
a project that I thought was a Cozy MKIV but was one of the very
first, other than Nats, 4 place Cozys. It is narrower in the
front by about 3 inches (original Cozy 3 dimensions) but is about the
same in other repects except the firewall is about 2 inches closer to
the landing gear bulkhead than the new plans versions.
Don't know how that will effect cg.
Have been thinking more about the fuel system and want the
finalize it soon. I put in returns in both tanks and feel I will
go ahead and use them and build the header tank slightly smaller than
the 15 inches mentioned earlier. Will use 2 outside the tank
pumps so no switching will be needed.
Wendell
Wendell,
would you please remind me what airplane you are building?
TJ