---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/21/05: 4 ---------------------------------------------------------- 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 _____________________________________ Time: 02:14:26 PM PST US From: Jan de Jong Subject: AeroElectric-List: Re: Capacitance style fuel level sensor --> AeroElectric-List message posted by: Jan de Jong 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 _____________________________________ Time: 06:54:49 PM PST US From: "Emrath" Subject: AeroElectric-List: Loan Analysis --> AeroElectric-List message posted by: "Emrath" 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 _____________________________________ Time: 10:17:22 PM PST US From: mprather Subject: Re: AeroElectric-List: Loan Analysis --> AeroElectric-List message posted by: mprather 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" > >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 _____________________________________ Time: 10:51:15 PM PST US From: GMC Subject: Re: AeroElectric-List: Loan Analysis --> AeroElectric-List message posted by: GMC Emrath wrote: >--> AeroElectric-List message posted by: "Emrath" > >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