REFLECTOR: Fuel sight guages..why?

[Terry Miles]

Alex, that was very well said.  I'm going to toss in on this topic too.  Not
that I have much to offer except my own experience (and hopes) to have
better fuel quant and fuel burn equipment than where the state of affairs
are now.  Like you, for now I am still relying only on my basic math skills
and stick readings and fuel truck readings, and will always be doing that as
fuel mgt method.  So much for the beauty of high tech!   

 

I have the Akinson sight gauges, and for some reason my LH one is blocked.
It worked fine for one day only when I was doing my mo-gas slosh of the
tanks during construction, which I drained back out immediately.  It was
some time later that I put in LL100 for the first time, and in the meanwhile
a little fleck of something decided to dry up and lodge over the opening to
the site gauge.  At present the gauge at about 3 gal level and no amount of
shucking and jiving and/or varied fuel loads wants to change that trapped
fuel in any.  The RH hand site gauge works just fine.  (And I agree, you
can't ever see the LH one anyway).  That said I am very glad I have them,
and glad I made a graduated dip stick too.

 

2nd issue:  When I refuel, I have the truck alternate with about 10 gal to L
tank than back to R tank and so forth until I have what I need.  I have only
done this a few times now, but the problem has been (with about a 60 of 80
gal requested fuel load) that I can wind up w a heavy wing (sometimes due to
ramp slope as a contributing issue) and when the heavy wing then sags
relative to the lighter wing, the fuel cannot transfer back so I have a 7 to
9 gallon wing to wing imbalance (based on stick readings) until I can get
taxiing or perhaps not until airborne.  

 

3rd comment: I have Princeton fuel probes that I bought from GRT and they
seem to stick at last reading while stationary on the ramp.  They have been
a pain in the neck all along.  I have tried recalibrating several times now
and that's been no help to their intermittent false readings.  I also bought
the GRT fuel flow calculator (flow-scan) add-on and it needs more test
flight tweaks to the digital offset entries to read correctly.  It on my
"things to do" list somewhere after but the belly skin back on.  Work is in
progress.  

 

Terry 

 

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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Alex Balic
Sent: Thursday, February 14, 2008 9:05 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Fuel sight guages..why?

 

Hi Brooke-

I for one have only the sight gauges and the fuel flow computer- IMHO the in
tank fuel gauges are a waste of panel space- or  just a waste of electricity
if you have them connected to a MFD.  The fuel flow computer can be pretty
accurate for burn rate, but not always, especially on mine, which has a
return line, so there are 2 transducers and the computer needs to do the
math to figure out how much is being burned- so less accuracy- also any
cavitation in the return line will make them even  less accurate- so I won't
really rely on them, just like I would not rely on just an airspeed
indicator and a timer to determine how far I have flown.  I have never ever
seen a truly accurate fuel quantity gauge- they are getting pretty good, but
I would never rely on one to give me accurate information other than, I have
about a half a tank, or now I have about a quarter tank- the only accurate
way to see how much fuel you have left is to do just that- SEE it- either
with a calibrated stick which is only good for when you are on the ground,
or with a calibrated sight gauge, which will tell you how much you have all
of the time-  no moving parts to break, no electricity required, and
perfectly accurate- I will use my flow meter to give general information,
and look over my shoulder to see how much gas I have- line leaks, fitting
leaks, cap leaks, compression loss on a cylinder,  electrical malfunctions,
does not matter- as long as there is gravity, and you can see, you will know
how much fuel you have.  If you read the NTSB reporter, you will know how
many pilots think that they have the fuel capacity/burn rate thing all
figured out- the lucky ones just end up in a field with a good hanger
story...

 

Alex

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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brooke Wolf
Sent: Thursday, February 14, 2008 9:45 AM
To: Velocity Aircraft Owners and Builders list
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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