In my experience capacitance types and resistive gauges are both unreliable.
I use and now sell a mechanical float device with internal reed switches.
200 sold so far and not one single return. Several Europa guys have fitted
them and they seem very pleased. Downside is you have to make a hole in the
tank and they are only 1/8th resolution which doesn't turn out to be a
restriction. Best of all they are inexpensive and very reliable. Two very
successful manufacturers have taken them on as standard fit and a third is
looking hard. They normaly provide infromation via a standard VDO fuel gauge
but they can be linked to an EIS or other digital device that eccpets a
varaible resistance input.
Jerry
LTS@avnet.co.uk
http://www.avnet.co.uk/touchdown
----- Original Message -----
From: Nick Hammond <nick.hammond@saabsystems.com.au>
Subject: RE: Fuel Tank shape
> Graham,
>
> Wouldn't the slight tank pressure head caused by the vent affect in-flight
> readings?
>
> Nick Hammond
>
> My choice of fuel contents gauge would now be a pressure sensor type. Non
> invasive, simply connect the sensor to either a drain connection or even
> the sight gauge.
> We tried a capacitance type but it was not very reliable, any water/
> condensation caused it to short out (the HF sensing signal) and read full
> scale, changes in fuel density caused false readings so we never really
> trusted it.
>
> Tony K has developed a good one, using bar graph LED display, I am also
> working on the same type of device (and loosely with him) . By the time
you
> are ready to use one it will certainly be available.
>
> Graham
>
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