Today's Message Index:
----------------------
0. 12:54 AM - Just Two Days Left... (Matt Dralle)
1. 01:53 AM - Re: sight gauge alternative (GRAHAM SINGLETON)
2. 02:28 AM - Re: sight gauge alternative (Jan de Jong)
3. 02:54 AM - Re: sight gauge alternative (Bob Harrison)
4. 02:28 PM - Re: sight gauge alternative (h&jeuropa)
5. 03:05 PM - Re: Re: sight gauge alternative (Jan de Jong)
6. 06:58 PM - Re: More Mod 78 Fun! (djaflyact)
Message 0
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| Subject: | Just Two Days Left... |
Dear Listers,
There are just a couple days left for this year's List Fund Raiser. If you've
been putting off making a Contribution until the last minute, well, this is it!
The last minute, that is... :-) There are some GREAT new gift selections to
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something you can't live without too! And, best of all it supports your
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Please remember that there isn't any sort of commercial advertising on the Lists
and the *only* means of keeping these Lists running is through your Contributions
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Please make a Contribution today!
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Thank you!
Matt Dralle
Matronics Email List Administrator
Message 1
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| Subject: | Re: sight gauge alternative |
Wonder what the difference between cabin pressure and fuel vent pressure is
? =0AGraham=0A=0A=0A=0A=0A________________________________=0A From: Jan de
Jong <jan_de_jong@casema.nl>=0ATo: europa-list@matronics.com =0ASent: Thurs
day, 28 November 2013, 20:20=0ASubject: Re: Europa-List: sight gauge altern
ative=0A =0A=0A=0AWhat 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.=0AAlmost any connection from sensor to the top of
the tank with=0A not-moving air in it will do, just like with pitot, st
atic and stall=0A warner lines. Non-moving means no friction pressure dr
op.=0AJan=0A=0A=0AOn 11/28/2013 8:25 PM, GRAHAM SINGLETON wrote:=0A=0A=0A>I
don't believe the shape and size of the vent has any=0A influence
- the air in the vent line(s) hardly moves.=0A>=0A>Regards,=0A>Jan de Jong
=0A>=0A>=0A>But it does have a pressure. That's what we are measuring=0A>
=0A>Graham=0A>=0A>=0A>=0A>=0A>________________________________=0A> From: Ja
n de Jong <jan_de_jong@casema.nl>=0A>To: europa-list@matronics.com =0A>Sent
: Thursday, 28 November 2013, 18:57=0A>Subject: Re: Europa-List: sight gaug
an_de_jong@casema.nl>=0A>=0A>I don't know whether it was mentioned but the
aircraft=0A attitude will always have an influence on the fuel
level=0A reading.=0A>The less one succeeds in mounting the se
nsor right below=0A the center of the tank the larger the infl
uence.=0A>One could measure pitch and do calibrations at several=0A
values and interpolate.=0A>I think that goes too far.=0A>I don't beli
eve the shape and size of the vent has any=0A influence - the
air in the vent line(s) hardly moves.=0A>=0A>-=- - - - - (And G
et Some AWESOME FREE Gifts!)=0A http://www.matronics.com/contrsp;=0A
- - - - - - -Matt Dralle, List Admin.=0A>> http://foru
ms.matronics===================0A>=0A>
======================
Message 2
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| Subject: | Re: sight gauge alternative |
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=================
>>
>>
>>
>>
>>
>> <http://www.matronics.com/Navigator?Europa-List>
>> <http://www.matronics.com/Navigator?Europa-List>
>> <http://www.matronics.com/Navigator?Europa-List>
>> <http://www.matronics.com/Navigator?Europa-List>
>> <http://www.matronics.com/Navigator?Europa-List>
>> *
>>
>> * <http://www.matronics.com/Navigator?Europa-List>
>> <http://www.matronics.com/Navigator?Europa-List>
>
> <http://www.matronics.com/Navigator?Europa-List>
> **follow" target="_blank" href="http://www.buildersbooks.com/">www.buildeblank" href="http://www.homebuilthelp.com/">www.homebuilthelp.com <http://www.aeroelectric.com/>
> **
> *
>
> *
> **
> **
> **
> *
> *
>
> *
> *
Message 3
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| Subject: | sight gauge alternative |
Hi! Guys,
I've been sort of watching your deliberations and have a small contribution
which may not be relevant but sufficiently important for me to speak up.
When you calibrate the fuel levels into any pressure sensing of the depth of
fuel being measured remember to "allow for" the fact that when the aircraft
is brim full the column of fuel above the tank top in the filler pipe
appears to nearly double the depth of fuel being measured.
I used to have one of Tony K's systems and so had great difficulty with
fixing the "Full" reading to actually represent the tank top volume which
greatly reduced the accuracy of the full range of readings. This is in no
way intended a criticism of his transducer system, but more an illustration
of my computer illiteracy !
For interest G-PTAG has no external tank vents but they actually pass into a
collection bottle in the cabin top( with a drain back to tank pipe) and
continue inside over the roof and down to exit near the port side flap
hinge bracket. I have never had any issues with venting or loss of fuel on
refuelling in any weather conditions or temperatures for my main Europa Tank
or my long range aluminium tank.
Regards
Bob Harrison G-PTAG Rotax 914.
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of GRAHAM
SINGLETON
Sent: 29 November 2013 09:53
Subject: Re: Europa-List: sight gauge alternative
Wonder what the difference between cabin pressure and fuel vent pressure is?
Graham
_____
From: Jan de Jong <jan_de_jong@casema.nl>
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 <mailto:jan_de_jong@casema.nl> <jan_de_jong@casema.nl>
Sent: Thursday, 28 November 2013, 18:57
Subject: Re: Europa-List: sight gauge alternative
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=================
<http://www.matronics.com/Navigator?Europa-List>
<http://www.matronics.com/Navigator?Europa-List>
<http://www.matronics.com/Navigator?Europa-List>
<http://www.matronics.com/Navigator?Europa-List>
follow <http://www.aeroelectric.com/> " target="_blank"
href="http://www.buildersbooks.com/">www.buildeblank"
href="http://www.homebuilthelp.com/">www.homebuilthelp.com
<http://www.mrrace.com/matronics.com/Navigator?Europa-List> "
href="http://forums.matronics.com/">http://forums.matronics.com============
=
Message 4
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| Subject: | Re: sight gauge alternative |
We originally copied some of Tony K's idea using the pressure transducer and op
amp he designed to get a 0-5 volt signal for our GRT EIS. It worked OK for
several years but there was always a problem of RF from the com transmitter causing
interference when transmitting.
We have now switched to Freescale (Motorola) integrated sensors, MPXV4006DP which
provide a 0-5 volt output for 0 - .87 psi. They are a differential sensor
so the liquid side is connected to the water drain pipe from the tank bottom
and the other side is connected to the tank vent. They only require a 5 volt
supply that we take directly from our EIS. We calculated that a full fuel tank
will have a head of pressure equal to about .4 psi. So we programmed the EIS
so that 0 - .4 psi gives an output of 0 - 100.
We have two of these sensors, one on the port (main) and one on the stbd (reserve).
In our GRT Sport EFIS we made the fuel calibration scales so that each side
goes from 0 - 3 gal and when there is 6 gallons in the tank so fuel is over
the saddle, then both read the same. The calibrations are in level flight attitude.
We have a sight gauge behind the seat back that is calibrated in the taildown attitude
(we have a mono). We use that to confirm at the end of the flight that
fuel used determined by the fuel totalizer in the EIS/EFIS is correct. We also
use the sight gauge to determine how much fuel to add.
We calibrated the sensors in level flight attitude so we have a in flight check
that the fuel totalizer and actual fuel used is correct. The other purpose
of these sensors is to give more confidence of how much fuel is aboard when the
tank is getting empty.
We've had no problems with using sensors with flouorosilicone seals and autofuel
(very seldom do we use 100LL). For our sight gauge we use Tygon SE200 which
has a flouoropolymer tube inside conventional clear tygon tubing. This tubing
does not discolor or degrade when exposed to gasoline. Use with single barbed
fittings.
Jim & Heather
N241BW XS, Mono, 914 500 hours
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=414535#414535
Message 5
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| Subject: | Re: sight gauge alternative |
Thank you. This seems to be the sensible solution. Temperature
compensation, gasoline compatible and inexpensive too. Without g-force
compensation but that is probably not so useful anyway. I am glad to
understand that the long lines between panel and sensor do not pick up
noticeable noise.
What kind of averaging time did you set the EIS input to?
Jan
On 11/29/2013 11:27 PM, h&jeuropa wrote:
> We have now switched to Freescale (Motorola) integrated sensors, MPXV4006DP
which provide a 0-5 volt output for 0 - .87 psi. They are a differential sensor
so the liquid side is connected to the water drain pipe from the tank bottom
and the other side is connected to the tank vent. They only require a 5 volt
supply that we take directly from our EIS. We calculated that a full fuel tank
will have a head of pressure equal to about .4 psi. So we programmed the
EIS so that 0 - .4 psi gives an output of 0 - 100.
>
Message 6
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| Subject: | Re: More Mod 78 Fun! |
More information on the dreaded Mod 78. It looks like the interference is the bolt
heads on the top of the CS08 brackets. By going with countersunk screws, the
spar should clear. Stay tuned.
I have not gotten the asking price for Charlie Bock's Tri-gear classic. I think
it is around $40K, but I need to verify that.
Dave
A227
Mini U2
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=414545#414545
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