REFLECTOR: Fuel sight guages..why?

Al Gietzen ALVentures at cox.net
Thu Feb 14 10:58:06 CST 2008


Brooke;

 

The key point is in your #2.  Because of the shape of the fuel tanks it is
very difficult to get a gauge to give a proper reading at more than a couple
points.  At least that is my experience. And the main issue is the case of a
cap leak which can cause uneven draining of the tanks.

 

Further; my experience is that in actual practice I rely upon my stick
measurement before a flight, and the fuel burn readout on the engine
monitor. And I make sure that the fuel caps seal properly. I installed a
capacitance probe gauge in one tank and an Atkinson sight gauge in the other
– thinking that it provided redundancy (since the tanks connect through the
sump) and convenience. I calibrated the probe readout to show correct at
empty and at ½ full. But I find that it has some ‘drift’ and can be
inconsistent by a few gallons.  I burn mogas, the clarity of which makes the
level difficult to see in the Atkinson sight gauge without a light.  So the
gauges are not my primary source for monitoring fuel.

 

Speaking of cap sealing – I used the caps that came with the kit back in
1997. I initially found the seal to be marginal even when greased. I found
that the o-rings were apparently a metric size, and that a 1/8” ring was
just slightly thicker and gives a better seal.

 

Al

 

 

Subject: REFLECTOR: Fuel sight guages..why?

 

Ok Guys, I have been pondering this question for some time.  Why do we have
fuel sight gauges in our Velocities?  The rationale for my doubt is as
follows:

 

1.      Before we fly, we visually observe and measure the fuel quantities
in each tank.  We know our fuel burn.  We know flying time.  Therefore we
always know our fuel state.  Nothing else required.  Unless

.

2.      We had fuel going somewhere other than into our cylinders.  IE we
have a leak!  Ok, we add fuel gauges.  My understanding is that fuel gauges
and associated sensing equipment is much more reliable than it was in my
1977 C172.

3.      Most installations have some sort of a fuel flow (fuel used)
computer to be used as a third source of fuel status.  Mine will.

 

There we have it.  Three layers of redundancy.  We could lose any two and
still be aware of our fuel state.  Why add more complexity to our machines
by bringing fuel inside the cabin?

 

Since so many people have the sight gauges, I fear I am missing something.
Your considered opinions and thoughts please





..at some point I am going
to be building the strakes!  Let me know what you think.

 

Thanks
..Brooke

XLRG-5

 

 

 

 

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