Today's Message Index:
----------------------
1. 02:14 PM - Re: Capacitance style fuel level sensor (Jan de Jong)
2. 06:54 PM - Loan Analysis (Emrath)
3. 10:17 PM - Re: Loan Analysis (mprather)
4. 10:51 PM - Re: Loan Analysis (GMC)
Message 1
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| Subject: | Re: Capacitance style fuel level sensor |
--> AeroElectric-List message posted by: Jan de Jong <jan.de.jong@xs4all.nl>
For a 1-chip capacitance-to-analog solution one might look at:
http://www.qprox.com/downloads/datasheets/qt301_106.pdf
It would require some experimenting with the sampling capacitor (Cs).
It would also need a high-impedance voltmeter (or a voltage follower -
there's chip nr 2)).
And the scale might not turn out quite linear (if Cx2 not much larger
than Cx2-Cx1).
But one may want to separately calibrate a scale for volume instead of
level anyway.
QT301 is $3.84 at Digikey, either 8-DIP or 8-SOIC.
QT300 and QT117L are both raw-output 16-bit capacitance-to-digital
converters (not all bits usable in any particular setup)
QT300 is $3.84 too, 8-SOIC.
QT117L is the simpler of the 2 but not at Digikey at all.
Not so timely, but I thought I'd mention it anyway.
Jan de Jong
Message 2
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--> AeroElectric-List message posted by: "Emrath" <emrath@comcast.net>
Bob and fellow Listers,
I've completed the suggested load analysis chart but no matter what I seem
to come up with the following loads, during night VFR decent.
Battery Buss Endurance Buss Main Buss Total
Day VFR 1.65 10.95 7.88 20.48 Amp
Night VFR 1.65 11.95 31.88 45.48 amp
Night VFR Decent 5.65 11.95 31.88 49.48 Amp
IFR Night Decent 5.65 11.95 21.88 39.48 Amp
So, looks like I need the 60 B&C Alt. These totals do not include Com Radio
Transmit loads or use of the power ports. I am sending a copy of the Excel
file directly to you for better review, but I know the Matronics List will
strip the attachment from this posting.
Here's the proposed equipment listing:
MAIN BUSS
Flaps Motor Van's 3.000 est.
Starter Contactor B&C 1.000 est.
Pitot Heat Warren Gretz 8.000
Strobe Lights Whelen 2.750
Nav Lights 6.000
Taxi Lights 9.000
Land Lights 9.000
Main Voltage Regulator B&C 2.000 est.
Auto Pilot - Navaid Ind. 0.125
Auto Pilot - Navaid Servo .75~3.6A 2.000 est.
Power Port 2.000
Battery Contactor B&C 1.000 est.
TOTAL MAIN BUSS 45.875
ENDURANCE BUSS
Audio panel Garmin 2.200
Garmin 430 GPS Garmin 430 1.400
Garmin 430 NAV Garmin 430 0.250
Garmin 430 COMM Garmin 430 6.000
OBS 0.250
Garmin Transponder Garmin 1.000
Aux Voltage Regulator 2.000 est.
Attitude IndicatorB.F.Goodrich0.750
Directional Gyro RC Allen 0.750
Turn Coordinator 0.750
UBG-16 Electronics Int'l 0.500
Oil Press/Temp EI 0.300
Amps/Volts EI 0.200
Fuel Level EI 0.300
Fuel Totalizer EI 0.300
LED Panel Lighting 1.000
TOTAL ENDURANCE BUSS 17.950
BATTERY BUSS
Super Clock 0.300
Jeff Rose EIS (switched) 0.750
RPM EI (switched) 0.300
MANIFOLD EI (switched) 0.300
Fuel Boost Pump (switched) 4.000 est.
Power Port 2.000
TOTAL BATTERY BUSS 7.650
As you can see, I'm planning an all electric panel, a Jeff Rose EIS, high
pressure fuel pump for Fuel Injected Lyc with C/S prop. Some of my power
loads are estimates right now. Perhaps you can tell me how to better
configure this system given that we need to try and keep the battery buss
plus endurance buss loads to 6 amps or less (I don't like the small relay
idea for loads above this). One thing I'm contemplating is moving all the
EI instruments to the Main Buss except for the RPM and put that on the
Endurance Buss.
I would sure apprecitate your thoughts, thanks for all your help.
Marty in Brentwood TN, RV6A
Do Not Archive
Message 3
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| Subject: | Re: Loan Analysis |
--> AeroElectric-List message posted by: mprather <mprather@spro.net>
Hi Marty,
It looks like many of the current specs you listed were peak, or max
values. 2.2A for an audio panel would be a lot. That's about 25watts -
enough to make very loud noises. 6A for a comm radio is a lot also.
That's better than 75watts. Even assuming 50% efficiency, you'd be
broadcasting better than 35watts. Most aircraft comm radios are in the
5-10watt range.
This issue seems to come up again and again.. People budget their
alternator size on the spec listed by the manufacturer. Manufacturers
don't give average operating current, usually just peak, or the size of
the breaker they'd like to see on the device. In the semiconductor
industry, that would just be unacceptable. We as a group of aircraft
engineers (that's the work we are doing) should start demanding better
datasheets from avionics manufacturers. Operating current specs with
their product in its various modes.
Regards,
Matt-
Emrath wrote:
>--> AeroElectric-List message posted by: "Emrath" <emrath@comcast.net>
>
>Bob and fellow Listers,
>I've completed the suggested load analysis chart but no matter what I seem
>to come up with the following loads, during night VFR decent.
>
> Battery Buss Endurance Buss Main Buss Total
>Day VFR 1.65 10.95 7.88 20.48 Amp
>Night VFR 1.65 11.95 31.88 45.48 amp
>Night VFR Decent 5.65 11.95 31.88 49.48 Amp
>IFR Night Decent 5.65 11.95 21.88 39.48 Amp
>So, looks like I need the 60 B&C Alt. These totals do not include Com Radio
>Transmit loads or use of the power ports. I am sending a copy of the Excel
>file directly to you for better review, but I know the Matronics List will
>strip the attachment from this posting.
>
>Here's the proposed equipment listing:
>
>MAIN BUSS
>Flaps Motor Van's 3.000 est.
>Starter Contactor B&C 1.000 est.
>Pitot Heat Warren Gretz 8.000
>Strobe Lights Whelen 2.750
>Nav Lights 6.000
>Taxi Lights 9.000
>Land Lights 9.000
>Main Voltage Regulator B&C 2.000 est.
>Auto Pilot - Navaid Ind. 0.125
>Auto Pilot - Navaid Servo .75~3.6A 2.000 est.
>Power Port 2.000
>Battery Contactor B&C 1.000 est.
>
>
>TOTAL MAIN BUSS 45.875
>
>
>ENDURANCE BUSS
>
>Audio panel Garmin 2.200
>Garmin 430 GPS Garmin 430 1.400
>Garmin 430 NAV Garmin 430 0.250
>Garmin 430 COMM Garmin 430 6.000
>OBS 0.250
>Garmin Transponder Garmin 1.000
>Aux Voltage Regulator 2.000 est.
>Attitude IndicatorB.F.Goodrich0.750
>Directional Gyro RC Allen 0.750
>Turn Coordinator 0.750
>UBG-16 Electronics Int'l 0.500
>Oil Press/Temp EI 0.300
>Amps/Volts EI 0.200
>Fuel Level EI 0.300
>Fuel Totalizer EI 0.300
>LED Panel Lighting 1.000
>
>TOTAL ENDURANCE BUSS 17.950
>
>BATTERY BUSS
>Super Clock 0.300
>Jeff Rose EIS (switched) 0.750
>RPM EI (switched) 0.300
>MANIFOLD EI (switched) 0.300
>Fuel Boost Pump (switched) 4.000 est.
>Power Port 2.000
>
>TOTAL BATTERY BUSS 7.650
>
>As you can see, I'm planning an all electric panel, a Jeff Rose EIS, high
>pressure fuel pump for Fuel Injected Lyc with C/S prop. Some of my power
>loads are estimates right now. Perhaps you can tell me how to better
>configure this system given that we need to try and keep the battery buss
>plus endurance buss loads to 6 amps or less (I don't like the small relay
>idea for loads above this). One thing I'm contemplating is moving all the
>EI instruments to the Main Buss except for the RPM and put that on the
>Endurance Buss.
>
>I would sure apprecitate your thoughts, thanks for all your help.
>Marty in Brentwood TN, RV6A
>
>
>
>
Message 4
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| Subject: | Re: Loan Analysis |
--> AeroElectric-List message posted by: GMC <gmcnutt@shaw.ca>
Emrath wrote:
>--> AeroElectric-List message posted by: "Emrath" <emrath@comcast.net>
>
>Bob and fellow Listers,
>I've completed the suggested load analysis chart but no matter what I seem
>to come up with the following loads, during night VFR decent.
>
> Battery Buss Endurance Buss Main Buss Total
>Day VFR 1.65 10.95 7.88 20.48 Amp
>Night VFR 1.65 11.95 31.88 45.48 amp
>Night VFR Decent 5.65 11.95 31.88 49.48 Amp
>IFR Night Decent 5.65 11.95 21.88 39.48 Amp
>So, looks like I need the 60 B&C Alt. These totals do not include Com Radio
>Transmit loads or use of the power ports. I am sending a copy of the Excel
>file directly to you for better review, but I know the Matronics List will
>strip the attachment from this posting.
>
>Here's the proposed equipment listing:
>
>MAIN BUSS
>Flaps Motor Van's 3.000 est.
>Starter Contactor B&C 1.000 est.
>Pitot Heat Warren Gretz 8.000
>Strobe Lights Whelen 2.750
>Nav Lights 6.000
>Taxi Lights 9.000
>Land Lights 9.000
>Main Voltage Regulator B&C 2.000 est.
>Auto Pilot - Navaid Ind. 0.125
>Auto Pilot - Navaid Servo .75~3.6A 2.000 est.
>Power Port 2.000
>Battery Contactor B&C 1.000 est.
>
>
>TOTAL MAIN BUSS 45.875
>
>
>ENDURANCE BUSS
>
>Audio panel Garmin 2.200
>Garmin 430 GPS Garmin 430 1.400
>Garmin 430 NAV Garmin 430 0.250
>Garmin 430 COMM Garmin 430 6.000
>OBS 0.250
>Garmin Transponder Garmin 1.000
>Aux Voltage Regulator 2.000 est.
>Attitude IndicatorB.F.Goodrich0.750
>Directional Gyro RC Allen 0.750
>Turn Coordinator 0.750
>UBG-16 Electronics Int'l 0.500
>Oil Press/Temp EI 0.300
>Amps/Volts EI 0.200
>Fuel Level EI 0.300
>Fuel Totalizer EI 0.300
>LED Panel Lighting 1.000
>
>TOTAL ENDURANCE BUSS 17.950
>
>BATTERY BUSS
>Super Clock 0.300
>Jeff Rose EIS (switched) 0.750
>RPM EI (switched) 0.300
>MANIFOLD EI (switched) 0.300
>Fuel Boost Pump (switched) 4.000 est.
>Power Port 2.000
>
>TOTAL BATTERY BUSS 7.650
>
>As you can see, I'm planning an all electric panel, a Jeff Rose EIS, high
>pressure fuel pump for Fuel Injected Lyc with C/S prop. Some of my power
>loads are estimates right now. Perhaps you can tell me how to better
>configure this system given that we need to try and keep the battery buss
>plus endurance buss loads to 6 amps or less (I don't like the small relay
>idea for loads above this). One thing I'm contemplating is moving all the
>EI instruments to the Main Buss except for the RPM and put that on the
>Endurance Buss.
>
>I would sure apprecitate your thoughts, thanks for all your help.
>Marty in Brentwood TN, RV6A
>Do Not Archive
>
>
>
Hi Marty
For a nice electrical load analysys format I like the one on Vern
Little,s web site at
http://www3.telus.net/aviation/flying/RV-9A/rv-9a.html
go to the Electrical/Avionics/Panel page for a link to his load analysys
format.
My comments are based on not completely understanding your system and
are worth what you paid for them but here goes..
The intermittent electrical load can exceed alternator output drawing
down the battery, the continuous electrical load should not exceed 80%
of alternator capacity allowing the battery to recharge.
Here in the Great White North the electrical load analysys is an
inflight consideration only and not for a system design analysys
therefore loads like starter contactor or ground only devices such as
taxi lights are not considered as flight electrical loads.
Items such as the flap motor, boost pump, etc are Intermittent loads
which may cause an intermittent alternator overload without a problem.
Items such as pitot heat & landing lights should be carefully evaluated
before placing them in a continuous or intermittent category, if the
aircraft is not certified for flight into icing conditions will the
pitot heat need to be operated continuously, will the landing lights be
operated continuously below 10K like the airlines or just for a few
minutes on final approach?
There is a question about alternator output, is it gross or net of the
regulator requirements.
The only specific item that does not look right on your load sheet is
that the strobe light draw looks on the low side.
George in Langley BC
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