Today's Message Index:
----------------------
1. 06:18 AM - Airframe ground joints (Robert L. Nuckolls, III)
2. 08:02 AM - Re: Load Analysis (Robert L. Nuckolls, III)
3. 08:48 AM - Re: Loan Analysis (Dave Morris)
4. 10:55 AM - Aux Batter Management Module (Jim Stone)
5. 11:46 AM - Dual Voltage System (marknlisa@hometel.com)
6. 12:24 PM - Intercom / Iso Amp Connection (Matthew Brandes)
7. 04:58 PM - Connection to main bus (RURUNY@aol.com)
8. 06:14 PM - Re: Intercom / Iso Amp Connection (Charlie England)
9. 06:40 PM - Re: Connection to main bus (Dave Morris \)
10. 07:56 PM - Load Analysis Revisited (Emrath)
11. 08:13 PM - Re: Load Analysis Revisited (Emrath)
12. 08:13 PM - Re: Re: Capacitance style fuel level sensor (Robert L. Nuckolls, III)
13. 08:17 PM - Re: Connection to main bus (Robert L. Nuckolls, III)
14. 08:18 PM - Re: Dual Voltage System (Robert L. Nuckolls, III)
15. 09:48 PM - How many busses? (Speedy11@aol.com)
16. 10:15 PM - Re: How many busses? (Bruce Gray)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Airframe ground joints |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>Comments/Questions: Dear Bob, I noted you made a posting in April on local
>grounds in the wings. You stated that doping the mating surfaces with
>"Silicon grease" would improve corrosion resistance. I'm building an RV7A
>that will be operated in a tropical environment and I'm very interested in
>corrosion control.
>
>Could you please tell me what is the name of a brand of acceptable silicon
>grease and where I could get it. I can't seem to find one in the Aircraft
>Spruce catalogue. Also, I would've thought silicon would be a non
>conductor and a thin film could adversely affect the performance of the
>ground. Why is this not the case.
First, the quality of a clean and smooth joint clamped up
with enough pressure to bring terminal and sheet metal
together in a gas tight connection will not be enhanced by
any magic glops or goops.
However, since smoothness may be difficult to control
one might offset the existence of microscopic openings to
the joint by application of some material likely to stay
in microscopic openings and offer some barrier to moisture and
corrosive gasses.
This can be about any material that is not itself antagonistic
to the metals. Liquid gasket materials from car parts stores
are good. Silicone grease (Dow Corning DC-4 comes to mind . .
but my tube is 40 years old and only 1/3 gone . . . don't know
were I'd look for another one). I would avoid vinegar smelling
RTV but the neutral smelling (electronic grades) are okay.
Dope the surfaces of the joint before you clamp them up. Where
you have achieved proper pressure in the joint, all sealant
will be extruded from the joint. Only fissures that didn't
close will contain remnants of sealant.
Having offered all this, your concerns are making a mountain out of
a mole-hill. Gazillions of dry, bolted-up joints have been performing
as intended for decades. Get the surfaces clean with scotch-brite,
bolt down with no smaller than #8 hardware torqued to limits
with metal lock nuts. Use heaviest available flat washers under
head of screw -AND- under the nut to provide stiffness to the
clamp up forces and your ground joints are going to be just
fine until long after the airplane has been scrapped. But if you
want to dope the joints, it won't hurt.
Bob . . .
--------------------------------------------------------
< Throughout history, poverty is the normal condition >
< of man. Advances which permit this norm to be >
< exceeded -- here and there, now and then -- are the >
< work of an extremely small minority, frequently >
< despised, often condemned, and almost always opposed >
< by all right-thinking people. Whenever this tiny >
< minority is kept from creating, or (as sometimes >
< happens) is driven out of a society, the people >
< then slip back into abject poverty. >
< >
< This is known as "bad luck". >
< -Lazarus Long- >
<------------------------------------------------------>
http://www.aeroelectric.com
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Load Analysis |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 08:52 PM 6/21/2005 -0500, you 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.
First, which Z-figure are you contemplating? Keep in mind that
an "endurance bus" is for continued cruising flight sans alternator
so as to get the most efficient used of limited resource . . .
energy in battery.
If you have an aux alternator of any size, then the term "endurance
bus" becomes less meaningful because you have second engine driven
power source that is not limited as to duration.
If you don't have a second alternator, then there's way too much
stuff on the e-bus. Get the loads down to the bare minimums for
sustained cruising flight for some duration you choose (fuel
aboard?) and KNOWN battery capacity in a device that you've chosen
and MAINTAINED well.
Since you're talking about electrically driven flight instruments,
I'll assume you have no vacuum pump and that you plan not to waste
a perfectly good drive pad by covering it up with a plate.
So, with a minimum of 8A continuous output available with
a crapped main alternator, then the e-bus is really just
an aux alternator bus with multiple feed paths. So, load it
to 8A (less battery bus loads) and quit.
If your design goals don't allow this (you insist on having
EVERYTHING working ALL THE TIME then you need a 20A aux alternator
and Z-14 is probably your better architecture. The e-bus goes
away.
You're correct, loads cited are for the most part, too large.
You need to get the real numbers before you can make any
meaningful decision. For example, IFR cruise runs no exterior
lights. If you're contemplating a Z-13 installation, provide
a means for reducing e-bus + battery bus loads to less than
8A. Do you run the fuel pump all the time or only during
failure of an engine driven pump. An electronic ignition that
needs 5A of supply current should be trashed in favor of one
that is 2A or less.
You list an AUX Voltage regulator . . . what is this? Regulators
do not have independent power requirements. They
operate on current allotted for supplying the alternator field
which is NOT deducted from the alternator's output ratings.
The largest full-up, all electric IFR load I've calculated to
date for a 14v airplane has been 27A. The 0.3A numbers for
all your instruments seems excessive. If I designed them, they
would be 0.1A max and probably lower.
1A for LED panel lighting? A C-172 uses a panel flood that
draws 0.2A max and .08A in cruising flight. Led lighting
should be on the same order or less.
Unless you're into really grand arrivals, consider how much
lighting you really need to have on in order to find your
way from the runway to parking in an orderly fashion.
I think you're going to find that a 40A machine is sufficient
and that an 8A alternator is a most adequate back-up for an
already very reliable 40A machine.
I've copied your load analysis spread sheet to my server at:
http://www.aeroelectric.com/PPS/Load_Analysis/Beeline%20load_analysis.xls
I'll encourage others to download, review, and offer current values
for things they may have measured or have data for.
Bob . . .
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Loan Analysis |
--> AeroElectric-List message posted by: Dave Morris <BigD@DaveMorris.com>
The S701-1 battery contactor runs about 750mA at 12V, measured.
Your panel can be illuminated by one or two Luxeon 1W LEDs or an Emeralight
strip. So figure on about 100mA for panel lighting.
Remember that there are 2 kinds of loads you want to consider: a) for fuse
and wire size determination, b) for endurance and bus determination
For endurance and bus decisions you need to know 2 load values: a) constant
and b) intermittent
The transponder II believe) only draws maximum power when it is
transmitting, which is not continuous
The com radio only draws maximum power when you are transmitting
The flaps motor only draws current at all when you are changing flap settings
The autopilot servo only draws current at all when moving.
Then, look at the items that have their own internal power switch, or whose
operation is totally under your control.
For example, you could leave a trim servo on the e-bus because you can
decide not to operate it if you need to conserve battery.
Realize that if you put it on the main bus, you will have to re-energize
the entire main bus in order to operate the servo.
Those are just some of the thought processes I have discovered are
necessary with my plane.
Dave Morris
At 08:52 PM 6/21/2005, you 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
>
>
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Aux Batter Management Module |
--> AeroElectric-List message posted by: "Jim Stone" <jrstone@insightbb.com>
Hi Guys,
I bought the Low Voltage Warning and Auxiliary Battery Management Module (ABMM)
because I have two batteries installed (Odyssey 680s).
After reading the instruction manual it seems I may not need it.
My setup is: Harmon Rocket, 1mag, 1 electronic ignition (electroair), B&C 40 amp
alt with voltage regulator and low voltage warning light (LR3c).
I'm thinking that since I don't have a stby alternator or electrically dependent
engine, I probably don't need a unit that is designed to shut the aux battery
down in the event of a primary alternator failure. Wouldn't it be just fine
to continue on to destination or nearest suitable field as appropriate with both
batteries on, while monitoring my volt meter?
And since I already have a warning light in the LR3c voltage regulator, I don't
need that function either, do I.
Anyone able to confirm my line of thinking?
Thanks,
Jim Stone
Louisville
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Dual Voltage System |
--> AeroElectric-List message posted by: marknlisa@hometel.com
Dilemma:
Must use 28 VDC starter; have already planned for 14 VDC system. Have
been thru the archives on Dual Voltage systems and this particular problem
hasn't been addressed.
Can I run two 12 VDC batteries in series to power the starter, but still
get 12 VDC power for accessories? If so, how?
Thanks for any help,
Mark
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Intercom / Iso Amp Connection |
--> AeroElectric-List message posted by: "Matthew Brandes" <matthew@n523rv.com>
I'm trying to wrap my head around my audio setup. I've just read the DIY
ISO Amp document as well as the new Chapter 18 on Audio systems. I think I
have it figured out but I do have two questions.
Can I output the audio from one of the DIY isolation amplifiers INTO a MIC
input on my PM 501 Mono Intercom?? I think the output of a microphone is
much less than most devices.
How do I wire the stereo output (MP3) into a mono input (ISO Amp). I have 4
devices that generate tones so that doesn't leave me with two inputs on the
ISO Amp for stereo input. Since everything else is mono, I don't
particularly require stereo, so would like to just wire both channels of
stereo into a single mono connection.
Matthew Brandes,
Van's RV-9A (Finish Kit)
#90569
<http://www.n523rv.com/> http://www.n523rv.com
EAA Chapter 1329 President
EAA Chapter 868 Web Editor
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Connection to main bus |
--> AeroElectric-List message posted by: RURUNY@aol.com
A quick question to the group. I am using drawing Z-16 Rotax 912, I have my
battery and battery contactor behind the passenger seat in my Zenith 701 and
not on the firewall.
Should I:
1) Run the 4 AWG wire from the battery contactor up thru the firewall,
connect to the
starter contacter, then run a separate wire from the starter contacter
back thru the
firewall to the main bus.
2) Run the 4 AWG wire from the battery contactor to the main bus fuse
block, then run
from the fuseblock thru the firewall to the starter contactor.
3) Run the 4 AWG wire from the battery contactor to a standalone terminal
from west marine
to a location up near the firewall and then 2 4AWG split from this
terminal to the main bus
and another thru the firewall to the starter contactor.
Thanks
Brian
_http://www.zenithair.com/bldrlist/profiles/bunruh/_
(http://www.zenithair.com/bldrlist/profiles/bunruh/)
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Intercom / Iso Amp Connection |
--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Matthew Brandes wrote:
>--> AeroElectric-List message posted by: "Matthew Brandes" <matthew@n523rv.com>
>
>I'm trying to wrap my head around my audio setup. I've just read the DIY
>ISO Amp document as well as the new Chapter 18 on Audio systems. I think I
>have it figured out but I do have two questions.
>
>Can I output the audio from one of the DIY isolation amplifiers INTO a MIC
>input on my PM 501 Mono Intercom?? I think the output of a microphone is
>much less than most devices.
>
>How do I wire the stereo output (MP3) into a mono input (ISO Amp). I have 4
>devices that generate tones so that doesn't leave me with two inputs on the
>ISO Amp for stereo input. Since everything else is mono, I don't
>particularly require stereo, so would like to just wire both channels of
>stereo into a single mono connection.
>
>
>Matthew Brandes,
>Van's RV-9A (Finish Kit)
>#90569
> <http://www.n523rv.com/> http://www.n523rv.com
>
Hi Matthew,
Not likely to be a good idea to feed the iso amp into a mic input; the
mic input has much higher gain than the regular audio inputs. Unsure why
you might need to do that; do you need extra inputs? Other options are
available to do this if needed.
You can make a 'summing' combiner using 2 each 10k ohm resistors, one
on each mp3 output & the other ends tied together to feed into the
destination.
If you don't mind me asking, what are the other sources you are feeding
into the iso amp? (The reason for asking is that most stuff doesn't need
the amp; it's usually just needed for consumer audio gear like the mp3
player.)
Charlie
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Connection to main bus |
--> AeroElectric-List message posted by: "Dave Morris \"BigD\"" <BigD@DaveMorris.com>
Well, Number 1 is a bad idea and not necessary.
In Number 2 you are implying that you need 4AWG to the main fuse block,
which you don't. You only need 4 gauge to the starter because of the huge
currents.
Number 3 is probably closest to reality, except that the run from the
splitter to the main fuse block can be much smaller gauge wire, sized to
accomodate the maximum loads and the distance of the run.
But basically you're asking where the tap should be, and since it's all DC,
it doesn't really matter and it's more your preference due to location
constraints more than anything else.
Use one of these http://www.quickcar.net/electric/57700.html to get the
high current wire through the firewall.
Dave Morris
At 06:56 PM 6/22/2005, you wrote:
>--> AeroElectric-List message posted by: RURUNY@aol.com
>
>A quick question to the group. I am using drawing Z-16 Rotax 912, I have my
>battery and battery contactor behind the passenger seat in my Zenith 701 and
>not on the firewall.
>
>Should I:
>
>1) Run the 4 AWG wire from the battery contactor up thru the firewall,
>connect to the
> starter contacter, then run a separate wire from the starter contacter
>back thru the
> firewall to the main bus.
>
>2) Run the 4 AWG wire from the battery contactor to the main bus fuse
>block, then run
> from the fuseblock thru the firewall to the starter contactor.
>
>3) Run the 4 AWG wire from the battery contactor to a standalone terminal
>from west marine
> to a location up near the firewall and then 2 4AWG split from this
>terminal to the main bus
> and another thru the firewall to the starter contactor.
>
>
>Thanks
>
>Brian
>
>_http://www.zenithair.com/bldrlist/profiles/bunruh/_
>(http://www.zenithair.com/bldrlist/profiles/bunruh/)
>
>
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Load Analysis Revisited |
--> AeroElectric-List message posted by: "Emrath" <emrath@comcast.net>
Bob, and others, thanks for all your thoughts and comments about this. I'm
planning on using Z-13 as a quide, All Electric ship with the SD-8. Good to
know that the regulators don't draw any load, so the alternator output is
net output and not gross output.
Since posting this request for help, I've learned that the Jeff Rose EIS
system draws 0.75 amps continuous, so that should be changed. I've yet to
measure my aux. fuel pump but will do so this weekend and report back,
however, I'm moving it to the main buss since if needed on landing I'll just
have to turn the master on to power that and the lights, but hey we're
almost home at that point (hopefully).
The panel lighting was a total swaq, but now we know that can be reduced but
I've also got to figure something for the back lighting of the Electronic
International instruments which might be 100ma each (eight instruments). I
will try contacting EI to find out exactly what the continuously run loads
are because the numbers I used sound like the wire/fuse load. I've also
learned that my strobe allotment might be too small and that might be
higher, anyone know what a single power supply for a three strobe ship will
require? What about the Garmin Audio Panel?
I'll send Bob my next revision tonight and perhaps he can post that in lieu
of my first attempt. My IFR cruise is 23.2amps (based on my estimated
numbers) and my VFR Night Cruise with all the lights on is 46.2 amps. My
battery buss is 1.05 amp and the endurance buss is 6.15 amp having moved the
audio panel to the main and kept the power to the gps and nav on the Garmin
430 on the Endurance which I'm not sure is OK ---any comments to that?
Keep those comments coming, all good ones so far, thanks.
Marty
Subject: Re: Load Analysis
From: Robert L. Nuckolls, III (nuckollsr@cox.net)
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
At 08:52 PM 6/21/2005 -0500, you 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.
<<snip>> <<snip>>
First, which Z-figure are you contemplating? Keep in mind that
an "endurance bus" is for continued cruising flight sans alternator
so as to get the most efficient used of limited resource . . .
energy in battery.
If you have an aux alternator of any size, then the term "endurance
bus" becomes less meaningful because you have second engine driven
power source that is not limited as to duration.
If you don't have a second alternator, then there's way too much
stuff on the e-bus. Get the loads down to the bare minimums for
sustained cruising flight for some duration you choose (fuel
aboard?) and KNOWN battery capacity in a device that you've chosen
and MAINTAINED well.
Since you're talking about electrically driven flight instruments,
I'll assume you have no vacuum pump and that you plan not to waste
a perfectly good drive pad by covering it up with a plate.
So, with a minimum of 8A continuous output available with
a crapped main alternator, then the e-bus is really just
an aux alternator bus with multiple feed paths. So, load it
to 8A (less battery bus loads) and quit.
If your design goals don't allow this (you insist on having
EVERYTHING working ALL THE TIME then you need a 20A aux alternator
and Z-14 is probably your better architecture. The e-bus goes
away.
You're correct, loads cited are for the most part, too large.
You need to get the real numbers before you can make any
meaningful decision. For example, IFR cruise runs no exterior
lights. If you're contemplating a Z-13 installation, provide
a means for reducing e-bus + battery bus loads to less than
8A. Do you run the fuel pump all the time or only during
failure of an engine driven pump. An electronic ignition that
needs 5A of supply current should be trashed in favor of one
that is 2A or less.
You list an AUX Voltage regulator . . . what is this? Regulators
do not have independent power requirements. They
operate on current allotted for supplying the alternator field
which is NOT deducted from the alternator's output ratings.
The largest full-up, all electric IFR load I've calculated to
date for a 14v airplane has been 27A. The 0.3A numbers for
all your instruments seems excessive. If I designed them, they
would be 0.1A max and probably lower.
1A for LED panel lighting? A C-172 uses a panel flood that
draws 0.2A max and .08A in cruising flight. Led lighting
should be on the same order or less.
Unless you're into really grand arrivals, consider how much
lighting you really need to have on in order to find your
way from the runway to parking in an orderly fashion.
I think you're going to find that a 40A machine is sufficient
and that an 8A alternator is a most adequate back-up for an
already very reliable 40A machine.
I've copied your load analysis spread sheet to my server at:
http://www.aeroelectric.com/PPS/Load_Analysis/Beeline%20load_analysis.xls
I'll encourage others to download, review, and offer current values
for things they may have measured or have data for.
Bob . . .
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | RE: Load Analysis Revisited |
--> AeroElectric-List message posted by: "Emrath" <emrath@comcast.net>
Listers:
I found an old email reply from Electronics International and the
instruments draw 100ma nominal and if back lighting is used and draw another
200ma at max. So, I'm planning on wiring the backlighting to the endurance
buss and just turn the light down or off and momentarily light them if
needed.
Marty
Message 12
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Capacitance style fuel level sensor |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 11:13 PM 6/21/2005 +0200, you wrote:
>--> 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.
Neat chip. I'll order some the next time I place a Digikey order.
This appears to be an excellent candidate for teaming with
a small micro-controller where one could do a direct measurement
of output duty cycle and convert to a value suited for transmission
by something more robust and versatile . . . serial data perhaps?
I'll toss this out to some of my fellow design wienies at RAC
and see what they come up with.
Bob . . .
Message 13
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Connection to main bus |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>Use one of these http://www.quickcar.net/electric/57700.html to get the
>high current wire through the firewall.
These are very useful if you don't want your firewall to be
a firewall anymore but simply a temporary barrier between
you and smelly things going on up front.
See:
http://aeroelectric.com/articles/Firewall_Penetration/firewall.html
and
http://www.epm-avcorp.com/tubeseal.html
Bob . . .
Message 14
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Dual Voltage System |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 01:44 PM 6/22/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: marknlisa@hometel.com
>
>Dilemma:
>
>Must use 28 VDC starter; have already planned for 14 VDC system. Have
>been thru the archives on Dual Voltage systems and this particular problem
>hasn't been addressed.
>
>Can I run two 12 VDC batteries in series to power the starter, but still
>get 12 VDC power for accessories? If so, how?
Dual voltage systems are generally practical only for items
that draw very little current where a small DC/DC converter
will suffice.
Why are you saddled with a 24v starter?
Bob . . .
Message 15
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | How many busses? |
--> AeroElectric-List message posted by: Speedy11@aol.com
I'm going to have about six groups of three each P&B W-31 switch circuit
breakers in my RV-8A. No need to address the fact I'm using CBs instead of fuses.
I understand those reasons, but I want to use CBs.
What I need to know is whether or not each group of three CBs should be
called a buss? Or should I call multiple groups of 3 each CBs a buss? Does it
really matter? Any problem with having, say, six "busses?"
Stan Sutterfield
Tampa
Message 16
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | How many busses? |
--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
Normal practice is to connect all CBs with a common brass strip on the
power side. All CBs connected to the same ganged brass strips are a
buss. So, you would have 2 electrically separated brass power strips,
one for your main buss and another for your endurance buss.
Bruce
www.glasair.org
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Speedy11@aol.com
Subject: AeroElectric-List: How many busses?
--> AeroElectric-List message posted by: Speedy11@aol.com
I'm going to have about six groups of three each P&B W-31 switch circuit
breakers in my RV-8A. No need to address the fact I'm using CBs instead
of fuses.
I understand those reasons, but I want to use CBs.
What I need to know is whether or not each group of three CBs should be
called a buss? Or should I call multiple groups of 3 each CBs a buss?
Does it
really matter? Any problem with having, say, six "busses?"
Stan Sutterfield
Tampa
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|