Peter
By proper differential pressure I assume you meant on one side there
will be the fluid pressure, and on the other side there will be tank
air pressure. I gathered from Paul's email that he did exactly this by
running the tank vent line to the sensor, but still sees a lag during
climbs and descents. This is most likely due to the large tank volume
and the small diameter of the vent tube. So it would matter exactly
where the vent line is teed off to go to the sensor. Closer to the
tank is better. In any case, this delay is likely to be
inconsequential because most of the spam cans I fly are only required
to have a reliable level indicator when the tank is really empty.
On Thu, Nov 28, 2013 at 8:38 AM, Peter Zutrauen <peterz@zutrasoft.com> wrote:
> I would suggest updating the cct/system to work on proper differential
> pressures - then venting isn't an issue. Ideally it would also incorporate a
> g-sensor such that a prolonged turn doesn't affect the fuel level reading
> (assuming there is some shorter duration filtering to deal with turbulence),
> and a switch to select avgas/mogas densities. I was planning on implementing
> such a system when the time came. I was also planning on a vertical aluminum
> tube gauge on the outside of the tank containing a magnetic float which
> triggered external level switches lighting up a simple led gauge - as a
> backup and in lieu of the sight-gauge.
>
> Cheers,
> Pete
> A239
>
>
> On Thu, Nov 28, 2013 at 8:11 AM, Rowland Carson <rowlandcarson@gmail.com>
> wrote:
>>
>> <rowlandcarson@gmail.com>
>>
>> On 28 Nov 2013, at 12:40, GRAHAM SINGLETON wrote:
>>
>> > isn't my vent system effectively the same as the factory setup? There
>> > will still be a +ve pressure on the tank.
>>
>> Graham - thanks for pointing that out. Until now, I hadn't noticed the
>> forward-pointing section at the end of the ultimate vent in your diagram as
>> posted here yesterday. I had assumed the vent would finish with a section
>> pointing vertically down (somewhere in the flap root area?) so as to
>> generate neither positive nor negative pressure, but probably cut off at an
>> angle to prevent whistles.
>>
>> in friendship
>>
>> Rowland
>>
>> | Rowland Carson ... that's Rowland with a 'w' ...
>> | <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
>> | Skype, Twitter: rowland_carson Facebook: Rowland Carson
>> | pictures: http://picasaweb.google.com/rowlandcarson
>>
>>
>>
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