Dave Tennant, Bob Harrson et al:
Thanks for the early comment. My diatribe was an attempt to make things
clearer for those following, and so the two replies are most valid. I
worry a bir about that long two-inch column of fuel behind my neck in
that rubbery snout on a max. weight takeoff.... I suppose, since I
haven't mentioned all that upper fuel in the calcs, that one shouldn't
really fuss about EXTRA fuel until it drops to the measured depth. The
previous depletion could be 'back-extrapolated' to coincide with the
fuel chit on volume, I guess.
Sorry, I forgot to add the first line details to my message on
the fuel tank. There was no serial number, but the tank was passed on
29NOV96.
AS measured, the tank did not fill completely as mentioned, so
that the overhang sector remained dry, and that section has great
volume. Wirhout getting into sines and cosines, it seems that to fill
the tank to full capacity, one would have to have mucho gasolini up the
filler spout, and the vent sealed off. I have not checked the advertised
volume so do not know whether this is usual and so may carry much more
fuel.
The height of fuel at which the two lower separated section
conjoin is a bit diffuse. When strictly level, the two meet at the front
of the tank, and when tipped back to Refuel Attitude, at the back of the
'saddle'. This accounts for the rounded form of the depth curve when the
points are plotted.
I hope to copy Nigel Charles' plan and have a sensor one each
side. His backup (dual flow) design is also a comfort as far as tank
changeover events is concerned. The instance of aeration (vapour lock)
rises dramatically when sources are changed (in my humble experience)
and this scheme 'plugs a few more loopholes'.
Nevertheless, I invite any corrections and will propagate if
needed. The exercise gives SOME idea of the profile of fuel use enroute.
It is left to fate to translate fuel "height" into gallons/litres.
Happy Landings,
Ferg A064
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