> I shall wait until something much simpler and easier to install
If one wishes to avoid the vagaries of capacitance senders, I found that
a mechanical sender works well enough. I drew the outline of half the
tank (looking from the front) on paper, marking gallons off as tested.
Then it was a simple matter of setting it up against this template to be
more accurate a low levels of fuel. I found also that bending the float
arm into an elliptical shape took out some of nonlinearity of the tank.
It's not then real accurate at around 3/4 tank up, but that doesn't
really matter.
I found also that rather than the junk the aircraft catalogs sell for
"experimentals," a boat supply place near me had a quality universal,
rheostat-type, float sender and better looking choices of panel gauge.
As long an experimenter with electronics, how we deal with tiny levels
of capacitance (a handful of picofarads) and design something stable and
accurate (beyond the varying fuel dielectrics), I will pose as
theoretically achievable at least.
My newish Toyota is the one built from many Lexus components, and just
about everything is controlled by "the computer." However, one input is
---From a simple float and rheostat, latter inside the fancy fuel pump in
the tank. Its digital display of "miles remaining" was found to
remarkably accurate even down under like 20 miles, long after its stern
warnings.
I even fiddled with it to see what a microcontroller would need to do to
present a similar display. However, between tank sloshing and
"hysteresis" of the rheostat wiper there's issues, but which should be
fixable with program code. However, the design of the steam gauge makes
this all moot. It would be nice to feed in engine RPM, plus airspeed
---From my uEncoder instrument, and present a choice of digital display
info. In addition to making it very accurate, we could have fuel flow,
(rough) distance, time, or gallons remaining. All from a $20 "boat"
rheostat, and a "step through" display button on the control stick, as
per Toyota on my steering wheel. A reasonable goal too for an actual
aircraft to mimic a mere $25K vehicle made by people actually earning
[huge] profits!
Reg,
Fred F.
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