Today's Message Index:
----------------------
1. 01:42 AM - Re: RV10 primary elec sys wiring (airknot)
2. 03:42 AM - Re: Use 1/4" hole on starter for engine ground? (Rowland Carson)
3. 07:03 AM - Re: Re: RV10 primary elec sys wiring (Charlie England)
4. 09:21 AM - Re: Re: RV10 primary elec sys wiring (C&K)
5. 10:48 AM - Re: RV10 primary elec sys wiring (user9253)
6. 11:17 AM - Re: Re: RV10 primary elec sys wiring (Bill Watson)
7. 12:10 PM - Re: Use 1/4" hole on starter for engine ground? (Robert L. Nuckolls, III)
8. 05:00 PM - Re: Use 1/4" hole on starter for engine ground? (rparigoris)
9. 07:47 PM - Z13-8 main alternator troubleshooting (rvtach)
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| Subject: | Re: RV10 primary elec sys wiring |
Dear Gents,
Revised my ELA calculations with assumtions:
-Comm system is working continiously during flight
-To start and taxi phases power consumtion for backupbatteries charging (G5, 2
-Skyview dispalys and IBBS backup battery) was added
-Pitot heating works during takeoff, approach and landing phases(icing conditions)
-fuel pump works during start, taxi, t/o, landing
please, critic me )
https://tinyurl.com/y6q2jrma
p.s. feel myself extremely self-doubt...
to check all real-life consumptions I must build primary elec system on airplane.
and hookup all the devices. or i am not right (
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498025#498025
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| Subject: | Re: Use 1/4" hole on starter for engine ground? |
On 2020-08-26, at 18:45, rparigoris <rparigor@hotmail.com> wrote:
> Hi Group I have a Rotax 914 with heavy duty starter. There is a casting at the
rear of the starter with an untapped 1/4" hole perhaps 1/2" thick. Is there
any reason why I couldn't use this as my only engine ground?
Ron - thats what I have done on the Rotax 912ULS in my Europa - see <http://www.rowlandcarson.org.uk/aviation/europa_435/starter_wires_a.php>. It seemed the obvious and sensible choice.
in friendship
Rowland
| Rowland Carson ... that's Rowland with a 'w' ...
| <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
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| Subject: | Re: RV10 primary elec sys wiring |
On Thu, Aug 27, 2020 at 3:47 AM airknot <airkbp@gmail.com> wrote:
>
> Dear Gents,
>
> Revised my ELA calculations with assumtions:
> -Comm system is working continiously during flight
> -To start and taxi phases power consumtion for backupbatteries charging
> (G5, 2 -Skyview dispalys and IBBS backup battery) was added
> -Pitot heating works during takeoff, approach and landing phases(icing
> conditions)
> -fuel pump works during start, taxi, t/o, landing
>
> please, critic me )
>
> https://tinyurl.com/y6q2jrma
>
> p.s. feel myself extremely self-doubt...
>
> to check all real-life consumptions I must build primary elec system on
> airplane. and hookup all the devices. or i am not right (
>
> You're doing fine; it takes multiple iterations to debug a design.
Go through it line by line, and play 'what if' for every situation you can
think of, related to that device, that leaves you able to make choices. If
night flight, lights on continuously. If mech fuel pump failure, boost pump
on continuously. Etc etc.
Go through again, line by line, asking how/when the device uses power, and
whether it's significant. The big deal is total energy (power *
time-active). Stuff that is almost never active can be ignored as part of
your continuous load. Ex: trim, flaps, comm's transmit current draw (which
is several times higher than 'idle' current), etc etc. Bob mentioned
'watt-seconds' earlier. If you have only one alternator, then after it
fails (assume that it will), then the battery(s) has some number of
watt-seconds of energy available in its 'tank'. An example battery might
have 12V * 18AH = 260 watt-hours, * 60 minutes = 12960 watt-seconds.
(Please check the math...) If, for example, the trim is activated for 2
seconds, it uses 0.15A * 12V = 1.8 watts, * 2 seconds = 3.6 watt-seconds
of energy while trimming. You probably couldn't use more than 100
watt-seconds from the battery for trimming, on the entire flight. Point is,
it's such a tiny percentage that it can be ignored, unless you have dozens
of those tiny items which could become significant if all operated, and all
operated continuously.
Examples of things that could be tweaked in the spreadsheet (not a
line-by-line analysis):
The comm can be listed at its lowest current. It only consumes the max
while transmitting, which is a tiny fraction of total time.
If you're going to fly IFR, the pitot heat should be listed as continuous,
because you may be in a marginal icing situation where you can't turn it
off. (That's what the 'worst case' thing means.)
You could probably zero out the trim current. Like the radio, it's only
operating a tiny fraction of the time, and shouldn't draw any current at
all while not operating.
Ask the mfgr about the oil cooler servo; like the trim servos, it shouldn't
draw any current unless operating.
Boost pump should be shown as continuous. 'Worst case' of mechanical fuel
pump failure during cruise would require running boost until landing.
Having fun yet?
Charlie
Message 4
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| Subject: | Re: RV10 primary elec sys wiring |
Very nice tutorial.
If the boost pump is normally off in cruise I'd also ignore that load
for an alternator failed scenario, same as for landing lights.
Ken
On 27/08/2020 9:58 AM, Charlie England wrote:
>
>
> On Thu, Aug 27, 2020 at 3:47 AM airknot <airkbp@gmail.com
> <mailto:airkbp@gmail.com>> wrote:
>
> <airkbp@gmail.com <mailto:airkbp@gmail.com>>
>
> Dear Gents,
>
> Revised my ELA calculations with assumtions:
> -Comm system is working continiously during flight
> -To start and taxi phases power consumtion for backupbatteries
> charging (G5, 2 -Skyview dispalys and IBBS backup battery) was added
> -Pitot heating works during takeoff, approach and landing
> phases(icing conditions)
> -fuel pump works during start, taxi, t/o, landing
>
> please, critic me )
>
> https://tinyurl.com/y6q2jrma
>
> p.s. feel myself extremely self-doubt...
>
> to check all real-life consumptions I must build primary elec
> system on airplane. and hookup all the devices. or i am not right (
>
> You're doing fine; it takes multiple iterations to debug a design.
>
> Go through it line by line, and play 'what if' for every situation you
> can think of, related to that device, that leaves you able to make
> choices. If night flight, lights on continuously. If mech fuel pump
> failure, boost pump on continuously. Etc etc.
> Go through again, line by line, asking how/when the device uses power,
> and whether it's significant. The big deal is total energy (power *
> time-active). Stuff that is almost never active can be ignored as part
> of your continuous load. Ex: trim, flaps, comm's transmit current draw
> (which is several times higher than 'idle' current), etc etc. Bob
> mentioned 'watt-seconds' earlier. If you have only one alternator,
> then after it fails (assume that it will), then the battery(s) has
> some number of watt-seconds of energy available in its 'tank'. An
> example battery might have 12V * 18AH = 260 watt-hours, * 60 minutes =
> 12960 watt-seconds. (Please check the math...) If, for example, the
> trim is activated for 2 seconds, it uses 0.15A * 12V = 1.8 watts, *
> 2 seconds = 3.6 watt-seconds of energy while trimming. You probably
> couldn't use more than 100 watt-seconds from the battery for trimming,
> on the entire flight. Point is, it's such a tiny percentage that it
> can be ignored, unless you have dozens of those tiny items which could
> become significant if all operated, and all operated continuously.
>
> Examples of things that could be tweaked in the spreadsheet (not a
> line-by-line analysis):
>
> The comm can be listed at its lowest current. It only consumes the max
> while transmitting, which is a tiny fraction of total time.
> If you're going to fly IFR, the pitot heat should be listed as
> continuous, because you may be in a marginal icing situation where you
> can't turn it off. (That's what the 'worst case' thing means.)
> You could probably zero out the trim current. Like the radio, it's
> only operating a tiny fraction of the time, and shouldn't draw any
> current at all while not operating.
> Ask the mfgr about the oil cooler servo; like the trim servos, it
> shouldn't draw any current unless operating.
> Boost pump should be shown as continuous. 'Worst case' of mechanical
> fuel pump failure during cruise would require running boost until landing.
> Having fun yet?
>
> Charlie
>
>
Message 5
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| Subject: | Re: RV10 primary elec sys wiring |
The battery contactor only draws 0.75 amps. See https://www.gigavac.com/sites/default/files/GX11B-GX12B-GX21B-Temp-Considerations.pdf
The USB sockets will not draw any current unless something is plugged in.
Even then, the 12 volt current draw will be less than half of the 5 volt current
(assuming switching power supply)
The clock only uses 0.1 amp. See https://iflyei.com/wp-content/uploads/SC-5-OI.pdf
The com radio only uses 0.6 amps unless the transmit button is continuously held
in.
The TCW - SERVO VALVE will not run continuously. Do not count its current.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498037#498037
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| Subject: | Re: RV10 primary elec sys wiring |
On 8/17/2020 9:41 PM, Robert L. Nuckolls, III wrote:
>
> With that engine, why are you including a backup
> battery? A 8-10A standby alternator on a vacuum
> pump pad offers UNLIMITED endurance with about
> a 4 pound penalty. I go out of my way to avoid
> adding batteries to a design over and above
> those normally expected to start engines and
> back up the primary alternator.
>
> Do you not PLAN to conduct periodic airworthiness
> checks on the main battery?
>
> Bob . . .
>
OP - I too have an RV10 with the 2 mag engine and a 3 display GRT
panel. I'll just add a couple of observations based on 9+ years and
1200+ hours of IFR intensive operation.
Bobs point above is dead on target for RV10 folks in particular - I have
a 40 amp main alt and a 20amp alt on the vacuum pad (B&C externally
controlled). That 2nd amp removes the main failure point that threatens
to actually shorten a flight and force a alternative landing. I had a
number of backup batteries connected to various avionic components but
found that it was a challenge maintaining them to the proper standard
for true reliance in case of failure. They've all come out and I simply
focus on my main battery. 2 Alternators and 1 battery is a real sweet spot.
But that's not what i have. I installed a Z-14 -2 alts, 2 batts, 2
buses, also known by Bob as 'everything and the kitchen sink' electrical
system. It's overkill by many measures but I love it. However I'd
recommend that the 'Z' with 2 alts and 1 battery is the optimal config
from a price-performance perspective. And like Bob said, get rid of
those other backup batteries.
It is commonly said that:
> Another point is to protect equipment during engine start
Absolutely NO equipment needs to be protected during engine start.
There is no such thing as voltage spikes during starting. That is an
old wive's tale. Are you going to believe rumors based on 1950's
technology or Bob N. who has written the book on aircraft electrical
systems?
True enuff I suppose but my panel did suffer from low voltage sagging during some
starts (cold wx combined with panel running before start with a less than fresh
battery and no extra avionics switches to manage total power reqmts). It
now simply reboots the displays if the voltage is too low but earlier it was
possible to corrupt the software if the load was abnormally interrupted. A SW
bug for sure but it happened.
Those displays, which come on with my master switch, are amp hogs. So I added
a now discontinued product from TCW - IPS (intelligent power stabilizer) which
has kept me from losing my displays for 5 years now. A well managed, big battery
combined with modern avionics should avoid this issue entirely.
So I'd suggest adding a small alternator on the vacuum pad, eliminating the extra
batteries and not worrying about the 60 amp alternator's ability to handle
anything you throw at it. It still has a battery behind it - the most reliable
component in the system. The Z designs are really well crafted and don't require
modification to use them successfully.
BTW, the Odyssey AGM batteries are really easy to manage and maintain with a volt
meter. Read the owners manual and follow it to the letter: 1) make sure your
charging system is set to run between 14.1 and 14.7 volts 2) Use a proper charger
if and when needed, 3) Keep it fully charged when inactive, 4) if 24hours
after charging, the voltage is less than 12.5 volts (75% capacity), replace
it. You might do that at 12.6 volts.
Bill "not reading the owners manual cost me 3 or 4 batteries before I became fully
literate" Watson
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Message 7
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| Subject: | Re: Use 1/4" hole on starter for engine ground? |
At 05:40 AM 8/27/2020, you wrote:
><rowlandcarson@gmail.com>
>
>On 2020-08-26, at 18:45, rparigoris <rparigor@hotmail.com> wrote:
>
> >> Hi Group I have a Rotax 914 with heavy duty starter. There is
> a casting at
> >> the rear of the starter with an untapped 1/4" hole perhaps 1/2" thick.
> >> Is there any reason why I couldn't use this as my only engine ground?
>
> > Ron - Tthat's what I have done on the Rotax 912ULS in my Europa
> > see
> <http://www.rowlandcarson.org.uk/aviation/europa_435/starter_wires_a.php>.
> > It seemed the obvious and sensible choice.
Rowland, thank you for posting this image . . . for
two reasons.
First, I was unaware of the existence of that boss
on the starter end bell casting . . . you're right,
that's a really good place to get a good electrical
connection to crankcase!
Second, I have concerns for the mechanical
integrity of this installation as photographed.
I perceived that the fat wires are probably
$high$ 'aircraft wire' . . . nice stuff . . .
stiff as a board. The wire has no mechanical
support TO THE ENGINE in close proximity to
the bolted joint.
The combination of stiff, heavy wire and
no support imparts vibrational stresses to
the terminal flag.
This is the CRANKCASE GROUND . . . usually
a very critical wire in the system.
We normally try to make that connection
with super flexible conductors that are
(1) resistance to flexure failures, (2)
does not impart strong flexure forces to the
terminal.
Alternatively, consider using welding cable.
Again, were looking for a bazillion strands
of copper cat-hair for conductors and flexible-
friendly installation. This article suggests
a method for soldering terminals onto fat
wires
https://tinyurl.com/ct36xen
. . . I need to upgrade that article to
suggest welding cable with double-wall
heat shrink as opposed to the stiff-stuff.
https://tinyurl.com/yysahtcf
Recommend you consider upgrading the two
strands of fat-wire that come off the back
of your engine. Welding cable with heat shrink
dressing won't require additional mechanical
support and you'll enjoy working with this
stuff.
But thanks for sharing that picture . . . that's
indeed an excellent crankcase connection point.
Bob . .
Message 8
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| Subject: | Re: Use 1/4" hole on starter for engine ground? |
Hi Bob "I need to upgrade that article to suggest welding cable with double-wall
heat shrink as opposed to the stiff-stuff"
I plan on using B&C #4 Super-Flex Battery Leads going from firewall to engine x2:
https://bandc.com/product/super-flex-battery-lead-red-raw-material/ when you
suggest using double wall heat shrink, are you suggesting to use only at terminal
lugs or the entire length of cable?? What type of heat shrink are you suggesting?
Thx. Ron
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498041#498041
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| Subject: | Z13-8 main alternator troubleshooting |
Hello expert electron herders-
I'm just finishing the phase one flight test on my O-360 powered RV-7A wired per
Z13-8 and I'm trying to troubleshoot a main alternator problem which is that
the alternator isn't putting out any voltage. I replaced the voltage regulator
(at less than $20 it seemed like a reasonable first step) and still no power
from the B&C 60 amp alternator.
Due to some poor planning on my part the VR is in a somewhat inaccessible location
which may have contributed to me hooking up the IASF leads on the replacement
VR incorrectly- I connected the "S" lead (which is jumpered to the "A" lead)
to the "I" tab. Wonder if that may have fried the voltage regulator?
At the hangar today I took some measurements and here's what I found:
Good continuity from the main bus, through the D/C power master switch to the VR-166
voltage regulator A/S terminal. 0.5 ohms.
Good continuity from the VR to the Alternator Field plug. 0 ohms.
Good continuity from the VR case to Firewall forest of tabs ground. 0 ohms.
With Master switch on and battery voltage at 12.5V there is no voltage at the alternator
field plug. It seems like there should be something on the order of
12V at the field plug, no?
Any suggestions before I just go out and buy a new VR-166?
A final note- I truly appreciate all the information I've gleaned from this forum
over the past 10+ years. Because of everything I've learned from Bob and all
the rest of you guys this is the only electrical problem I've had- everything
else has been perfect. Beyond my hopes!!
Cheers-
Jim
--------
Jim McChesney
Tucson, AZ
RV-7A Finishing Kit
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498043#498043
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