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jacklockamy(at)verizon.ne
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 Posted: Sat Oct 28, 2006 1:37 pm Post subject: Back-up Alternator |
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Last Thursday, after 245 hours on my RV-7A (0-320/160 HP), I suffered my SECOND, Van's 60-AMP, internally regulated alternator, failure! (The first alternator failed at 160 hrs!) I have a cooling blast tube aimed at the rear of the alternator and still don't know why these alternators keep failing. Since it was a NAPA rebuilt, Lester alternator #14684 with a three-year warranty, I was able to get the alternator replaced today for FREE!
I fly over mountainous terrain, IFR and occasionally at night, For this reason, I am concerned with alternator failures and have decided to install a back-up alternator on the un-used vacuum pump pad on my Lycoming 0-320/conical mount engine....
Question: How much does the B&C SD-20 weigh? I normally run with about 14-18 AMP loads and figure I need the SD-20 instead of the SD-8 (8-10 AMPS but lighter weight?) to have a reliable back-up alternator for my electrical load during night/IFR flight.
Question: I have my -7A wired using Bob's Z-11 architecture with a Van's 60-AMP internally regulated alternator. If I purchase and install the B&C SD-20 alternator, do I connect it to the Dynon EMS-10 firewall mounted shunt or connect the SD-20 to the Odyssey PC-680 battery directly in case the Van's recommended alternator takes another crap? Spoke with Gus at Van's on Thursday and wasn't able to determine if there was a problem with their wiring directions or if the #14684 alternators were the problem here.
BTW.... the Odyssey PC-680 battery kept me flying for approx. 1:45 minutes after the alternator failed. I was using flight following as usual and informed them that I had an alternator failure and would prefer to use the IDENT button on my King KT-76A transponder to acknowledge freq changes and/or traffic calls rather than use the juice in the battery when transmitting on the Comm-1 radio. This worked extremely well and I wasn't forced to use un-necessary volts using my transmit button on Comm-1. Using this method of acknowledgement, I was able to conserve valuable battery voltage for almost 2-hours and I landed with 11.5 volts in the PC-680. NOTE: I was prepared to squawk 7600 and had informed 'Center' that if I went NORDO (No Radio), I would squawk 7600, and would be expecting light signals (flashing green light?) from Camarillo Tower for landing permission. If you inform Center of your problem, they will assist. When I first informed Albuquerque Center of my alternator problem, the controller asked if I was declaring an emergency. My reply was "No... I have enough battery voltage to maintain flight (dual Slick Magnetos) and MONITOR Comm-1". I was switched to more than 6-7 different sector controllers and not once was I required to key the radio... just hit the IDENT button on the transponder and each controller acknowledged.... "Ident observed". Saves the juice.... I had the TRIO Avionics A/P, ALTRAK ALT-HOLD A/P, ICOM-A200 VHF Transceiver, DYNON EFIS-D10, DYNON EMS-D10 Engine monitor, King KT-76A Transponder and AvMAP EKP-IV Moving map GPS running the entire time....
Bottom Line: Use the IDENT button on your transponder to acknowledge radio calls rather than transmit on the radio and use valuable battery reserves.
Jack Lockamy
Camarillo, CA
RV-7A N174JL 245 hrs
www.jacklockamy.com
jacklockamy(at)verizon,net ([email]jacklockamy(at)verizon,net[/email])
[quote][b]
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endspeed(at)yahoo.com
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| Posted: Sat Oct 28, 2006 5:35 pm Post subject: Back-up Alternator |
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Hi Jack,
The SD-20 weighs 5.72 lbs. according to the B&C
drawing SD20 last revised 2/24/03.
Bob Sultzbach
--- JACK LOCKAMY <jacklockamy(at)verizon.net> wrote:
| Quote: | Last Thursday, after 245 hours on my RV-7A
(0-320/160 HP), I suffered my SECOND, Van's 60-AMP,
internally regulated alternator, failure! (The
first alternator failed at 160 hrs!) I have a
cooling blast tube aimed at the rear of the
alternator and still don't know why these
alternators keep failing. Since it was a NAPA
rebuilt, Lester alternator #14684 with a three-year
warranty, I was able to get the alternator replaced
today for FREE!
I fly over mountainous terrain, IFR and occasionally
at night, For this reason, I am concerned with
alternator failures and have decided to install a
back-up alternator on the un-used vacuum pump pad on
my Lycoming 0-320/conical mount engine....
Question: How much does the B&C SD-20 weigh? I
normally run with about 14-18 AMP loads and figure I
need the SD-20 instead of the SD-8 (8-10 AMPS but
lighter weight?) to have a reliable back-up
alternator for my electrical load during night/IFR
flight.
Question: I have my -7A wired using Bob's Z-11
architecture with a Van's 60-AMP internally
regulated alternator. If I purchase and install
the B&C SD-20 alternator, do I connect it to the
Dynon EMS-10 firewall mounted shunt or connect the
SD-20 to the Odyssey PC-680 battery directly in case
the Van's recommended alternator takes another crap?
Spoke with Gus at Van's on Thursday and wasn't able
to determine if there was a problem with their
wiring directions or if the #14684 alternators were
the problem here.
BTW.... the Odyssey PC-680 battery kept me flying
for approx. 1:45 minutes after the alternator
failed. I was using flight following as usual and
informed them that I had an alternator failure and
would prefer to use the IDENT button on my King
KT-76A transponder to acknowledge freq changes
and/or traffic calls rather than use the juice in
the battery when transmitting on the Comm-1 radio.
This worked extremely well and I wasn't forced to
use un-necessary volts using my transmit button on
Comm-1. Using this method of acknowledgement, I
was able to conserve valuable battery voltage for
almost 2-hours and I landed with 11.5 volts in the
PC-680. NOTE: I was prepared to squawk 7600 and
had informed 'Center' that if I went NORDO (No
Radio), I would squawk 7600, and would be expecting
light signals (flashing green light?) from Camarillo
Tower for landing permission. If you inform Center
of your problem, they will assist. When I first
informed Albuquerque Center of my alternator
problem, the controller asked if I was declaring an
emergency. My reply was "No... I have enough
battery voltage to maintain flight (dual Slick
Magnetos) and MONITOR Comm-1". I was switched to
more than 6-7 different sector controllers and not
once was I required to key the radio... just hit the
IDENT button on the transponder and each controller
acknowledged.... "Ident observed". Saves the
juice.... I had the TRIO Avionics A/P, ALTRAK
ALT-HOLD A/P, ICOM-A200 VHF Transceiver, DYNON
EFIS-D10, DYNON EMS-D10 Engine monitor, King KT-76A
Transponder and AvMAP EKP-IV Moving map GPS running
the entire time....
Bottom Line: Use the IDENT button on your
transponder to acknowledge radio calls rather than
transmit on the radio and use valuable battery
reserves.
Jack Lockamy
Camarillo, CA
RV-7A N174JL 245 hrs
www.jacklockamy.com
jacklockamy(at)verizon,net
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nuckollsr(at)cox.net
Guest
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| Posted: Sat Oct 28, 2006 5:37 pm Post subject: Back-up Alternator |
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Subject: Back-up Alternator
To: "AeroElectric List" <aeroelectric-list(at)matronics.com>
Last Thursday, after 245 hours on my RV-7A (0-320/160 HP), I suffered my
SECOND, Van's 60-AMP, internally regulated alternator, failure! (The first
alternator failed at 160 hrs!) I have a cooling blast tube aimed at the
rear of the alternator and still don't know why these alternators keep
failing. Since it was a NAPA rebuilt, Lester alternator #14684 with a
three-year warranty, I was able to get the alternator replaced today for FREE!
It's nice that the expense is so accommodating . . . but
a boat-load of no-cost alternators may well forever fall
short of design goals.
I fly over mountainous terrain, IFR and occasionally at night, For this
reason, I am concerned with alternator failures and have decided to install
a back-up alternator on the un-used vacuum pump pad on my Lycoming
0-320/conical mount engine....
It's been a perennial recommendation here on the List
that no vacuum pump pad should go wasting with a cover
plate on it.
Question: How much does the B&C SD-20 weigh? I normally run with about
14-18 AMP loads and figure I need the SD-20 instead of the SD-8 (8-10 AMPS
but lighter weight?) to have a reliable back-up alternator for my
electrical load during night/IFR flight.
. . . but why support "normal" loads? How much stuff do you
really need during the en route phase of flight to get airport
of intended destination in sight with a fully charged battery
to assist the standby alternator in running whatever electro-whizzies
you wish for descent and approach to landing?
Question: I have my -7A wired using Bob's Z-11 architecture with a Van's
60-AMP internally regulated alternator. If I purchase and install the B&C
SD-20 alternator, do I connect it to the Dynon EMS-10 firewall mounted
shunt or connect the SD-20 to the Odyssey PC-680 battery directly in case
the Van's recommended alternator takes another crap? Spoke with Gus at
Van's on Thursday and wasn't able to determine if there was a problem with
their wiring directions or if the #14684 alternators were the problem here.
Why are you choosing to stay with the brand/model of alternator
sold/recommended by Van's? We KNOW that other brands bolted to
Lycoming engines have produced exemplary service records. Aside
from weak design and/or poor workmanship, there no reason that
an alternator should not run for TBO on the engine. It would seem
prudent that the first order of the day is to replace a demonstrably
poor performing alternator.
BTW.... the Odyssey PC-680 battery kept me flying for approx. 1:45 minutes
after the alternator failed. I was using flight following as usual and
informed them that I had an alternator failure and would prefer to use the
IDENT button on my King KT-76A transponder to acknowledge freq changes
and/or traffic calls rather than use the juice in the battery when
transmitting on the Comm-1 radio. This worked extremely well and I wasn't
forced to use un-necessary volts using my transmit button on
Comm-1. Using this method of acknowledgement, I was able to conserve
valuable battery voltage for almost 2-hours and I landed with 11.5 volts in
the PC-680.
The energy needed to occasionally transmit is a trivial
part of the total required for comfortable continuation
of flight. While "helpful" to a tiny degree it was not
necessary.
If you are running Z-11, what was your predicted battery
only endurance value?
NOTE: I was prepared to squawk 7600 and had informed 'Center' that if I
went NORDO (No Radio), I would squawk 7600, and would be expecting light
signals (flashing green light?) from Camarillo Tower for landing
permission. If you inform Center of your problem, they will assist. When
I first informed Albuquerque Center of my alternator problem, the
controller asked if I was declaring an emergency. My reply was "No... I
have enough battery voltage to maintain flight (dual Slick Magnetos) and
MONITOR Comm-1". I was switched to more than 6-7 different sector
controllers and not once was I required to key the radio... just hit the
IDENT button on the transponder and each controller acknowledged.... "Ident
observed". Saves the juice.... I had the TRIO Avionics A/P, ALTRAK
ALT-HOLD A/P, ICOM-A200 VHF Transceiver, DYNON EFIS-D10, DYNON EMS-D10
Engine monitor, King KT-76A Transponder and AvMAP EKP-IV Moving map GPS
running the entire time....
Bottom Line: Use the IDENT button on your transponder to acknowledge radio
calls rather than transmit on the radio and use valuable battery reserves.
Your experience was much more tense than it needed
to be. You have too much electro-stuff running in the
endurance mode. Your choice to use IDENT for
communication with the ground was immaterial to the
outcome of your experience. The fact that you were
so worried about outcome that you felt compelled to save a
few watt-minutes of energy suggests that the outcome
was not a sure bet in your own mind . . . i.e. you were
not sure by reason of satisfied design goals that the
battery would get you there sans alternator.
I respectfully suggest that a killobuck SD-20 installation
that adds about 8# to the airplane is not as practical as
spending a similar amount of money for a main alternator
with an exemplary track record (no or small weigh penalty).
Back it up with an 8A alternator (also exemplary track
record) for a 3.5# weight penalty. Tailor loads
on the endurance bus so in the now unlikely event that
the main alternator craps, you have proven, designed-in
capabilities to get where you want to go with nary
second thought about punching the MIC button to tell
the ground, "everything is cool."
Main alternator performance is fundamental to the "no-
sweat design" along with a well maintained RG battery. Piling
a high dollar BandAid on a system with demonstrably
flawed fundamentals is only going to have you flying along
wondering when the "next interesting flight" is going to
happen. How about designing for "never"?
Bob . . .
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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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| Posted: Sun Oct 29, 2006 9:13 am Post subject: Back-up Alternator |
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10/29/2006
Responding to a posting From: "JACK LOCKAMY" <jacklockamy(at)verizon.net>
Hello Jack, Thank you for sharing your story with us. I sympathize with your
situation and congratulate you on its successful outcome.
You wrote: "Bottom Line: Use the IDENT button on your transponder to
acknowledge
radio calls rather than transmit on the radio and use valuable battery
reserves."
I'd like to explore this recommendation a bit further. First having the
radio in receive only mode by not transmitting would definitely conserve
battery. But having the transponder on continuously would consume battery at
some higher rate than when OFF or STANDBY, even when not IDENTING, because
the transponder is being constantly interrogated and responding to external
interrogators.
Maybe the underlying assumption in your recommendation is that: A) FAR
91.215 could require one to have the transponder on, and B) ATC needs your
transponder ON and the IDENTING in order to provide any useful services,
including air traffic separation.
I guess my question is whether or not there could be a circumstance where
one would prefer to have the radio on and transmitting only as needed while
keeping the transponder OFF or in STANDBY in order to better conserve
battery?
OC -- The best investment we will ever make is in gathering knowledge.
PS: A review of the Odyssey battery specs shows that the PC 625 has more
overall amperage capability than the PC 680. I wonder if we should not
switch to the PC 625 at the next battery change over?
http://www.odysseyfactory.com/specs.htm
PPS: Regarding using Vans recommended alternators: "Fool me once, shame on
you. Fool me twice, shame on me."
Time: 02:37:00 PM PST US
From: "JACK LOCKAMY" <jacklockamy(at)verizon.net>
Subject: Back-up Alternator
Last Thursday, after 245 hours on my RV-7A (0-320/160 HP), I suffered my
SECOND, Van's 60-AMP, internally regulated alternator, failure! (The
first alternator failed at 160 hrs!) I have a cooling blast tube aimed
at the rear of the alternator and still don't know why these alternators
keep failing. Since it was a NAPA rebuilt, Lester alternator #14684
with a three-year warranty, I was able to get the alternator replaced
today for FREE!
I fly over mountainous terrain, IFR and occasionally at night, For this
reason, I am concerned with alternator failures and have decided to
install a back-up alternator on the un-used vacuum pump pad on my
Lycoming 0-320/conical mount engine....
Question: How much does the B&C SD-20 weigh? I normally run with about
14-18 AMP loads and figure I need the SD-20 instead of the SD-8 (8-10
AMPS but lighter weight?) to have a reliable back-up alternator for my
electrical load during night/IFR flight.
Question: I have my -7A wired using Bob's Z-11 architecture with a
Van's 60-AMP internally regulated alternator. If I purchase and
install the B&C SD-20 alternator, do I connect it to the Dynon EMS-10
firewall mounted shunt or connect the SD-20 to the Odyssey PC-680
battery directly in case the Van's recommended alternator takes another
crap? Spoke with Gus at Van's on Thursday and wasn't able to determine
if there was a problem with their wiring directions or if the #14684
alternators were the problem here.
BTW.... the Odyssey PC-680 battery kept me flying for approx. 1:45
minutes after the alternator failed. I was using flight following as
usual and informed them that I had an alternator failure and would
prefer to use the IDENT button on my King KT-76A transponder to
acknowledge freq changes and/or traffic calls rather than use the juice
in the battery when transmitting on the Comm-1 radio. This worked
extremely well and I wasn't forced to use un-necessary volts using my
transmit button on Comm-1. Using this method of acknowledgement, I
was able to conserve valuable battery voltage for almost 2-hours and I
landed with 11.5 volts in the PC-680. NOTE: I was prepared to squawk
7600 and had informed 'Center' that if I went NORDO (No Radio), I would
squawk 7600, and would be expecting light signals (flashing green
light?) from Camarillo Tower for landing permission. If you inform
Center of your problem, they will assist. When I first informed
Albuquerque Center of my alternator problem, the controller asked if I
was declaring an emergency. My reply was "No... I have enough battery
voltage to maintain flight (dual Slick Magnetos) and MONITOR Comm-1". I
was switched to more than 6-7 different sector controllers and not once
was I required to key the radio... just hit the IDENT button on the
transponder and each controller acknowledged.... "Ident observed".
Saves the juice.... I had the TRIO Avionics A/P, ALTRAK ALT-HOLD A/P,
ICOM-A200 VHF Transceiver, DYNON EFIS-D10, DYNON EMS-D10 Engine monitor,
King KT-76A Transponder and AvMAP EKP-IV Moving map GPS running the
entire time....
Bottom Line: Use the IDENT button on your transponder to acknowledge
radio calls rather than transmit on the radio and use valuable battery
reserves.
Jack Lockamy
Camarillo, CA
RV-7A N174JL 245 hrs
www.jacklockamy.com
jacklockamy(at)verizon,net
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deej(at)deej.net
Guest
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| Posted: Sun Oct 29, 2006 9:56 am Post subject: Back-up Alternator |
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JACK LOCKAMY wrote:
| Quote: | Bottom Line: Use the IDENT button on your transponder to acknowledge
radio calls rather than transmit on the radio and use valuable battery
reserves.
|
Someone please correct me if this is incorrect, but aren't most
transponders something like 200-250 watts transmit power, and most comm
radios somewhere around 5-10 watts transmit power? If so, wouldn't it
use more battery power to have the transponder transmit versus the comm
radio?
Thanks,
-Dj
--
Dj Merrill
Sportsman 2+2 Builder #7118
http://econ.duke.edu/~deej/sportsman/
"TSA: Totally Screwing Aviation"
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retasker(at)optonline.net
Guest
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| Posted: Sun Oct 29, 2006 10:42 am Post subject: Back-up Alternator |
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True, except that the transponder transmits for microseconds while the
comm transmits for seconds. Therefore, the average power used in
transmissions of the transponder is much less than the comm.
On the other hand, if the use of the transmission capabilities of either
of these devices would make the difference in making it to your planned
destination or not, then you better get on the ground right now!
Dick Tasker
Dj Merrill wrote:
| Quote: |
JACK LOCKAMY wrote:
>Bottom Line: Use the IDENT button on your transponder to acknowledge
>radio calls rather than transmit on the radio and use valuable battery
>reserves.
>
>
Someone please correct me if this is incorrect, but aren't most
transponders something like 200-250 watts transmit power, and most comm
radios somewhere around 5-10 watts transmit power? If so, wouldn't it
use more battery power to have the transponder transmit versus the comm
radio?
Thanks,
-Dj
|
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Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
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nuckollsr(at)cox.net
Guest
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| Posted: Sun Oct 29, 2006 10:51 am Post subject: Back-up Alternator |
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At 12:55 PM 10/29/2006 -0500, you wrote:
| Quote: |
JACK LOCKAMY wrote:
> Bottom Line: Use the IDENT button on your transponder to acknowledge
> radio calls rather than transmit on the radio and use valuable battery
> reserves.
Someone please correct me if this is incorrect, but aren't most
transponders something like 200-250 watts transmit power, and most comm
radios somewhere around 5-10 watts transmit power? If so, wouldn't it
use more battery power to have the transponder transmit versus the comm
radio?
|
The transponder speaks in very narrow pulses arranged
so as to digitally identify you and report your altitude.
This is accomplished at a very low duty cycle . . . so while
PEAK power is on the order of 100-200 watts, the AVERAGE power
is less that what's consumed by most COMM transmitters while
talking. Having said that, the COMM transmitter is also
very low duty cycle. You may LISTEN to the radio for 1 hour
with at say 100 mA for a total power consumption of 0.1a x 11.5v
x 3600s is 4140 watt seconds. Your transmitter may raise this current to
say 2 amps. Assume you speak for 60 seconds total out of an
hour and we have 2 x 11.5 x 60 or 1380 watt-seconds. The 17 a.h. battery
supplying your e-bus being discharged at say 4 amps is good for
about 3 hours so 11.5v x 4a x 3hrs x 3600s = 496,800 watt seconds.
So, it's easy to see that if one has scaled their e-bus loads
to take advantage of say 75% of the battery in 3 hours (372,000
watt-seconds) then the addition of 3 minutes of "mic time" to
the mix increases total energy expenditure by about 0.3% . . .
a trivial portion of the total budget.
The same mistake is commonly made when considering energy
needed to crank an engine . . . 200+ amps for say 10 seconds
is only a tad over 20,000 watt-seconds. Only about 5% of the
total energy contained in a 17 a.h. battery.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
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