The maximum would be around 0.5 psi: the (pitot - static) differential
pressure at 150 kts or so.
About as large as the hydrostatic pressure difference caused by a full tank.
So venting the pressure port for the "air column" to the cabin is a bad
idea; it has to go to the top of the tank with no leaks or movement of air.
On 11/29/2013 10:52 AM, GRAHAM SINGLETON wrote:
> Wonder what the difference between cabin pressure and fuel vent
> pressure is?
> Graham
>
>
> ------------------------------------------------------------------------
> *From:* Jan de Jong <jan_de_jong@casema.nl>
> *To:* europa-list@matronics.com
> *Sent:* Thursday, 28 November 2013, 20:20
> *Subject:* Re: Europa-List: sight gauge alternative
>
> What you hope to measure is the difference in hydrostatic pressure
> caused by the "column" of fluid in the tank and the same "column" of
> air outside the tank.
> Almost any connection from sensor to the top of the tank with
> not-moving air in it will do, just like with pitot, static and stall
> warner lines. Non-moving means no friction pressure drop.
> Jan
>
> On 11/28/2013 8:25 PM, GRAHAM SINGLETON wrote:
>>
>> I don't believe the shape and size of the vent has any influence -
>> the air in the vent line(s) hardly moves.
>>
>> Regards,
>> Jan de Jong
>>
>> But it does have a pressure. That's what we are measuring
>> Graham
>>
>> ------------------------------------------------------------------------
>> *From:* Jan de Jong <jan_de_jong@casema.nl>
>> <mailto:jan_de_jong@casema.nl>
>> *To:* europa-list@matronics.com <mailto:europa-list@matronics.com>
>> *Sent:* Thursday, 28 November 2013, 18:57
>> *Subject:* Re: Europa-List: sight gauge alternative
>>
>> <mailto:jan_de_jong@casema.nl>>
>>
>> I don't know whether it was mentioned but the aircraft attitude will
>> always have an influence on the fuel level reading.
>> The less one succeeds in mounting the sensor right below the center
>> of the tank the larger the influence.
>> One could measure pitch and do calibrations at several values and
>> interpolate.
>> I think that goes too far.
>> I don't believe the shape and size of the vent has any influence -
>> the air in the vent line(s) hardly moves.
>>
>> -= (And Get Some AWESOME FREE Gifts!)
>> http://www.matronics.com/contrsp; -Matt Dralle, List Admin.
>> > http://forums.matronics=================
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