On Sunday, September 9, 2007, at 07:58 AM, ALAN YERLY wrote:
> Sight gauge woe's. The fix is to install the Mod 33 and use the drain
> line as your lower sight gauge hookup point.- The static fuel at the
> rear of the tank allows the site gauge to be quite stable in flight.-
> For those of you who put the sight gauge in the seat back like I have,
> it works fine (tri-gear).- The longer tube lengths for those of you
> with the sight gauge near the foot well, acceleration does cause the
> fuel to move.- Remember to use the FSO2 to help stabilize the > reading
s.
I've been rassling w/ these issues...wanting to have a positive visual
(reliable) for both in-flight fuel, as well as a simple visual
reference when refueling...and now have the following set up. I'm
installing both a modified factory sight gauge as well as one between
the seat backs. My factory sight gauge T's off the main tank fuel drain
with an FS 02 inserted, but where the line goes vertical at the
footwell, I'm opting to use 90 degree barbed fittings top and bottom so
that I can contain a small redux/micro sphere float (painted w/ bright
yellow butyrate dope); sphere will be contained within the vertical w/
a bit of SS wool @ the barbs. I can live with the extra clamps for the
fittings. Vent line will continue to starboard (rather than port) and
rearward just below the door sill before rising alongside the filler
neck and venting below the flap as Bud described.
For the gauge between the seats, which also T's off the main tank drain
line, I'm using a piece of rigid pipe (ACS P/N 03-54100); it will also
have a redux/micro float. As I'm uncomfortable venting it between the
underside of the top of the CM and the tank, I've made a T-shaped
splash molding over foam which extends down to the tunnel; the
"crossing" of the T provides a lip which dies into the head rests and
provides a void in which the vent will reside before it penetrates the
starboard head rest and eventually Ts into the other sight gauge vent
line...this may sound complex, but it's really quite simple. Since my
reason for the seat back gauge is solely as a visual reference when
refueling, I want to be sure that it registers fuel level in the tank
as fuel is poured in. I have some concerns that if an FS 02 restrictor
is used, the fuel level in the sight gauge will lag behind the actual
level in the tank, rendering its utility suspect, if the point of
having it is to avoid spillage. Consequently, my thinking is to NOT use
an FS 02 in this line, recognizing that stable readings in flight may
result and if so would not affect the
footwell sight gauge at all.
I must confess to being a believer in redundancy for critical systems,
as I have also installed the factory electric float gauge.
All just grist for the mill,
Fred
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