Today's Message Index:
----------------------
1. 03:53 AM - 14V or 28V (Carlos Trigo)
2. 06:55 AM - Re: 14V or 28V (Roger & Jean)
3. 06:56 AM - Re: 14V or 28V (Charlie England)
4. 07:35 AM - Re: 14V or 28V (Bill Bradburry)
5. 11:17 AM - Re: two com radios (toddheffley)
6. 03:17 PM - Re: 14V or 28V (donjohnston)
7. 05:00 PM - COM radio/intercom wiring problem... (Michael Burbidge)
8. 05:29 PM - Re: COM radio/intercom wiring problem... (Michael Burbidge)
9. 06:31 PM - Re: Re: 14V or 28V (Henador Titzoff)
10. 08:27 PM - Re: 14V or 28V (Robert L. Nuckolls, III)
11. 08:32 PM - Re: COM radio/intercom wiring problem... (Robert L. Nuckolls, III)
12. 08:36 PM - Re: two com radios (Robert L. Nuckolls, III)
13. 08:43 PM - Re: Alternators on aircraft (Robert L. Nuckolls, III)
14. 09:15 PM - Re: COM radio/intercom wiring problem... (Bill Putney)
15. 09:18 PM - Re: COM radio/intercom wiring problem... (Michael Burbidge)
16. 10:46 PM - Re: two com radios (Sacha)
17. 10:48 PM - Re: two com radios (Sacha)
Message 1
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Guys
I suppose this has been discussed before, but my laziness to search in the
archives makes me raise this issue again.
In the RV-10 that I am building, I am thinking in using a 12V(14V)
electrical system, most probably based in the Nuckolls's Z-14 architecture,
with the VP-X Pro box.
However, when searching for the Comm radios to choose from, I found that the
best radios, in terms of transmitting power (16W), are 28V.
Should I consider changing all the electric system to 28V, or is it possible
to have a 14V system and include a 14/28 voltage "converter" to feed the
radio?
All opinions welcome
Regards
Carlos
Message 2
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> In the RV-10 that I am building, I am thinking in using a 12V(14V)
> electrical system, most probably based in the Nuckolls's Z-14
> architecture,
> with the VP-X Pro box.
>
> However, when searching for the Comm radios to choose from, I found that
> the
> best radios, in terms of transmitting power (16W), are 28V.
> Should I consider changing all the electric system to 28V, or is it
> possible
> to have a 14V system and include a 14/28 voltage "converter" to feed the
> radio?
28 volt systems have become the normal for many new production
aircraft. You can use lighter fat wires and thus save a bit of
weight.
All of the electrical components are available in either voltage.
I would recommend that you go with one voltage or the other, and not
try to
run a dual voltage machine. Just keep in mind that if you go with a
28 volt
system, you must keep all other electrical items such as, starter,
lighting,
contactors and anything else plugged into the system, compatable
with the
28 volts.
Roger
Message 3
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On 07/27/2013 05:49 AM, Carlos Trigo wrote:
>
> Guys
>
> I suppose this has been discussed before, but my laziness to search in the
> archives makes me raise this issue again.
> In the RV-10 that I am building, I am thinking in using a 12V(14V)
> electrical system, most probably based in the Nuckolls's Z-14 architecture,
> with the VP-X Pro box.
>
> However, when searching for the Comm radios to choose from, I found that the
> best radios, in terms of transmitting power (16W), are 28V.
> Should I consider changing all the electric system to 28V, or is it possible
> to have a 14V system and include a 14/28 voltage "converter" to feed the
> radio?
>
> All opinions welcome
> Regards
> Carlos
>
Unless you're operating in an environment where the last 1/2 mile of
range matters, don't worry about it. VHF is basically line of site, &
even a 3W handheld (with a proper external antenna) can reach the
horizon unless you're flying at airliner altitudes. I'm too lazy to dig
up the math, but here's a rough rule of thumb: If you want to double
your range, multiply power by 10.
Charlie
Message 4
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In an experimental plane, you will save a few ounces, maybe even a pound or
two in smaller wires, but you will add 10-15 pounds for the larger battery.
If you decide you should install two batteries...WOW! You will not find any
automotive parts that are 28V. I suggest you will need a reason better than
weight savings to go 28V.
B2
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Roger &
Jean
Sent: Saturday, July 27, 2013 9:54 AM
Subject: Re: AeroElectric-List: 14V or 28V
<mrspudandcompany@verizon.net>
> In the RV-10 that I am building, I am thinking in using a 12V(14V)
> electrical system, most probably based in the Nuckolls's Z-14
> architecture,
> with the VP-X Pro box.
>
> However, when searching for the Comm radios to choose from, I found that
> the
> best radios, in terms of transmitting power (16W), are 28V.
> Should I consider changing all the electric system to 28V, or is it
> possible
> to have a 14V system and include a 14/28 voltage "converter" to feed the
> radio?
28 volt systems have become the normal for many new production
aircraft. You can use lighter fat wires and thus save a bit of
weight.
All of the electrical components are available in either voltage.
I would recommend that you go with one voltage or the other, and not
try to
run a dual voltage machine. Just keep in mind that if you go with a
28 volt
system, you must keep all other electrical items such as, starter,
lighting,
contactors and anything else plugged into the system, compatable
with the
28 volts.
Roger
Message 5
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Subject: | Re: two com radios |
John
I wonder if you have considered an alternative solution to a installed second com?
My experience with hand crafted audio control systems has been 100% negative,,,,
meaning poorly thought out, no documentation, making repair a puzzling endeavor.
My favorite set up for a VFR/CrossCountry/LightIFR aircraft is:
ONE com. The best quality you can afford. CI122 antenna on the belly, Meaning a
REAL antenna, not just a cheapy 1/4 wave stick, not a internal antenna. Best
practices on coax termination and so forth. Carefully think through Bob's well
documented Zdiagrams to give the unit the bast chance of rock solid power +
some type of Plan B power.
A intercom correctly installed with the direct Mic/Phone jacks wired, as well
as the Pilot/Copilot/Pax mic/phone jacks. NAT is my favorite, but that is because
I am a snob.
My point is, put most of you eggs in that basket and make that basket FIRST RATE.
Secondly, a backup com system that is a REAL backup.
Meaning, a handheld radio, SOLIDLY afix the panel or side wall. Separate mic and
phone jacks wired ONLY to the handheld. A DEDICATED 2nd com antenna hooked directly
to the handheld.
FRESH batteries, and/or Fresh spare batteries in the flight bag.
This approach gets rid of the audio panel, a single point of failure, and divides
the cost of the second com in half.
I recommend this after YEARS of working on light aircraft with poorly maintained,
2nd rate avionics.
Best wishes for you and your project.
Todd
--------
WWW.toddheffley.com
www.theinterconnectco.com for lighting products
AV-TS.com for Jet Aircraft Test Equipment
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=405436#405436
Message 6
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bbradburry(at)bellsouth.n wrote:
> In an experimental plane, you will save a few ounces, maybe even a pound or
> two in smaller wires, but you will add 10-15 pounds for the larger battery.
> If you decide you should install two batteries...WOW! You will not find any
> automotive parts that are 28V. I suggest you will need a reason better than
> weight savings to go 28V.--
I would agree. I'm building a 28v system and the... adjustments I've had to make
are a bit of a pain. If I were starting from scratch, I'd probably go with a
14v system.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=405443#405443
Message 7
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Subject: | COM radio/intercom wiring problem... |
I'm trying to chase down a problem with my Radio (Garmin SL-40) Intercom (Flightcom
403) wiring. One of the strange behaviors that I don't understand is when
I push the PTT to transmit on a common unicom frequency such as 122.7, the ammeter
pegs at -40 amps. When I transmit on one of the maintenance frequencies
such as 135.85, it only deflects negative 1-2 amps. But the radio is transmitting,
I can hear on my handheld.
My ammeter is a shunt type ammeter and seems to work correctly in indicating positive
(discharge) loads for other equipment. What would make it indicate in
the negative directions. This is using just the battery. i.e. engine not running.
The situation is that I'm trying to debug my initial wiring, so the setup has never
worked.
Thanks for any hints.
Michael-
Message 8
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Subject: | Re: COM radio/intercom wiring problem... |
I should note that the ammeter shunt is measuring alternator current. It is installed
as in the Z-11 electrical system, between the starter contractor and the
"b" lead on the alternator.
This could very well be expected behavior when on battery only.
Michael-
On Jul 27, 2013, at 4:59 PM, Michael Burbidge <mburbidg@gmail.com> wrote:
>
> I'm trying to chase down a problem with my Radio (Garmin SL-40) Intercom (Flightcom
403) wiring. One of the strange behaviors that I don't understand is when
I push the PTT to transmit on a common unicom frequency such as 122.7, the
ammeter pegs at -40 amps. When I transmit on one of the maintenance frequencies
such as 135.85, it only deflects negative 1-2 amps. But the radio is transmitting,
I can hear on my handheld.
>
> My ammeter is a shunt type ammeter and seems to work correctly in indicating
positive (discharge) loads for other equipment. What would make it indicate in
the negative directions. This is using just the battery. i.e. engine not running.
>
> The situation is that I'm trying to debug my initial wiring, so the setup has
never worked.
>
> Thanks for any hints.
>
> Michael-
>
>
>
>
Message 9
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Don, Bill, Carlos,=0A=0A=0AApart from the 14V vs. 28V debate, I'd like to p
oint out that one doesn't necessarily have to add 10-15 lbs for the "28V" b
attery, i.e. it isn't necessarily that much of a "larger" battery. 12V batt
eries have six plates, while "28V" batteries have 12 plates.- If one need
s the same amount of power at the starter, an equally sized "28V" battery w
ith smaller plates will do the job, since P = E*I.- Voltage goes up, bu
t current goes down in the same proportion, or slightly less since the volt
age drops to the starter will sum less. In summary, same battery size, same
energy density, just higher voltage with less current needed.=0A=0AEnough
theory, now let's look at real world numbers. I've put quotes around the 28
Vs above, because 28V aircraft batteries are actually 24V, as one can see a
t the following link:=0A=0A---- http://www.concordebattery.com/alla
ircraftbatteries.php=0A=0A=0ANote that the Concorde CB-25 12V battery weigh
s 22 lbs, while the CB24-11 24V battery weighs 27 lbs. If Carlos plans his
electrical system well, surely he can make up that additional 5 lbweight by
using fat wires.=0A=0AHenador Titzoff=0A=0A=0A=0A=0A______________________
__________=0A From: donjohnston <don@velocity-xl.com>=0ATo: aeroelectric-li
st@matronics.com =0ASent: Saturday, July 27, 2013 6:16 PM=0ASubject: AeroEl
ectric-List: Re: 14V or 28V=0A =0A=0A--> AeroElectric-List message posted b
y: "donjohnston" <don@velocity-xl.com>=0A=0A=0Abbradburry(at)bellsouth.n wr
ote:=0A> In an experimental plane, you will save a few ounces, maybe even a
pound or=0A> two in smaller wires, but you will add 10-15 pounds for the l
arger battery.=0A> If you decide you should install two batteries...WOW!-
You will not find any=0A> automotive parts that are 28V.- I suggest you
will need a reason better than=0A> weight savings to go 28V.--=0A=0A=0AI wo
uld agree. I'm building a 28v system and the... adjustments I've had to mak
e are a bit of a pain. If I were starting from scratch, I'd probably go wit
h a 14v system.=0A=0A=0A=0A=0ARead this topic online here:=0A=0Ahttp://foru
=================
Message 10
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At 09:34 AM 7/27/2013, you wrote:
><bbradburry@bellsouth.net>
>
>In an experimental plane, you will save a few ounces, maybe even a pound or
>two in smaller wires, but you will add 10-15 pounds for the larger battery.
not strictly true. When going to a higher voltage system
a battery with 1/2 the a.h. capacity has the same stored
energy as the lower voltage battery.
>If you decide you should install two batteries...WOW! You will not find any
>automotive parts that are 28V. I suggest you will need a reason better than
>weight savings to go 28V.
The weight savings are pretty small . . . we did
some calculations on it way back when here on the
list. Not very impressive until you considered
a sea-plane with very long + and ground leads.
Many of the compelling reasons for 28v circulating
in the wild are more fantasy or error than face. See
page 12 and on in this document.
http://tinyurl.com/k9v2rfw
A 28v battery at 1/2 capacity will not be as roubust
to the effects of cranking events.
Cessna went 100% 28v for manufacturing conveniences
and before the advent of the higher efficiency, geared
light weight starters.
It would be interesting to see those economics
re-evaluated but in the certified, heavy iron
business, it's not likely to happen.
The most compelling reason cited for 28v here on
the list was "my engine came fitted with 28v hardware
and I didn't what to change it out."
Bob . . .
Message 11
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Subject: | Re: COM radio/intercom wiring problem... |
At 06:59 PM 7/27/2013, you wrote:
>
>I'm trying to chase down a problem with my Radio (Garmin SL-40)
>Intercom (Flightcom 403) wiring. One of the strange behaviors that I
>don't understand is when I push the PTT to transmit on a common
>unicom frequency such as 122.7, the ammeter pegs at -40 amps. When I
>transmit on one of the maintenance frequencies such as 135.85, it
>only deflects negative 1-2 amps. But the radio is transmitting, I
>can hear on my handheld.
>
>My ammeter is a shunt type ammeter and seems to work correctly in
>indicating positive (discharge) loads for other equipment. What
>would make it indicate in the negative directions. This is using
>just the battery. i.e. engine not running.
>
>The situation is that I'm trying to debug my initial wiring, so the
>setup has never worked.
You didn't say but I'm betting your ammeter is
the one Van's sells . . . minus 40 - zero - plus
40?
I have one of those things laying around here somewhere.
I think I reported to the List after I bought it that
the instrument was very vulnerable to strong RF
in the cockpit.
What kind of airplane and where is your antenna
located? Have you checked VSWR on the antenna
over the vhf comm range?
Bob . . .
Message 12
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Subject: | Re: two com radios |
At 02:07 AM 7/26/2013, you wrote:
><jmtipton@btopenworld.com>
>
>Hi Guys (Bob)
>
>I'd like to fit 2 x radio coms, I don't want or need a full 'audio
>panel' what are my options, I guess I really need is some kind of
>sophisticated change-over switch
>
>John
Have you considered 1 comm radio and a hand-held?
My flight bag always carried this constellation of
back-ups . . . even when I was flying an A36 with
all the goodies.
http://tinyurl.com/d5mrjgh
The nice thing about this line-up is that it's
totally independent of the airplane's electrical
system no matter which airplane you're flying.
Bob . . .
Message 13
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Subject: | Re: Alternators on aircraft |
At 03:10 PM 7/26/2013, you wrote:
>How often is there a scenario where an aircraft or automobile
>alternator needs to be balanced? Is this something that needs to be
>considered?
>
>Bill B
Depends on how you define 'need'. B&C started
balancing their rotors many years ago based
on the fact that belt driven alternators on
a Lycoming cruise at about 2x the rpm in cars.
2x speed is 4x the vibrational forces due to
unbalance.
Van's used to sell a larger pulley to 'slow
down' the alternators he sold/recommended.
Takes care of the cruise vibration but degreades
output at ground ops rpms. B&C elected to
maintain the performance and do a simple
operation to mitigate vibration.
B&C's track record has been exemplary. Would
it have been noticeably degraded if not balanced?
Don't know. It's a bearing life issue and doesn't
represent a large cost-of-ownership or flight
risk.
If your experience shows that you're shucking
bearings too often, then balancing or slowing
down are options. If you buy a B&C, those
concnerns are addressed with the package.
Bob . . .
Message 14
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Subject: | Re: COM radio/intercom wiring problem... |
40 Amps is 480 watts at 14V. That's a lot for an aircraft radio to pull. It's an
8 watt transmitter and just keying the mic with no modulation it would be a
fraction of that (it's an AM transmitter). The radio has an internal 7A fuse and
the installation manual says to use a 5A external fuse or breaker.
I'm thinkin' there's something wonkie with the ammeter or the grounding for the
avionics or the meter electronics.
Bill
Sent from my iPad
On Jul 27, 2013, at 8:32 PM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
> At 06:59 PM 7/27/2013, you wrote:
>>
>> I'm trying to chase down a problem with my Radio (Garmin SL-40) Intercom (Flightcom
403) wiring. One of the strange behaviors that I don't understand is when
I push the PTT to transmit on a common unicom frequency such as 122.7, the
ammeter pegs at -40 amps. When I transmit on one of the maintenance frequencies
such as 135.85, it only deflects negative 1-2 amps. But the radio is transmitting,
I can hear on my handheld.
>>
>> My ammeter is a shunt type ammeter and seems to work correctly in indicating
positive (discharge) loads for other equipment. What would make it indicate
in the negative directions. This is using just the battery. i.e. engine not running.
>>
>> The situation is that I'm trying to debug my initial wiring, so the setup has
never worked.
>
>
> You didn't say but I'm betting your ammeter is
> the one Van's sells . . . minus 40 - zero - plus
> 40?
>
> I have one of those things laying around here somewhere.
> I think I reported to the List after I bought it that
> the instrument was very vulnerable to strong RF
> in the cockpit.
>
> What kind of airplane and where is your antenna
> located? Have you checked VSWR on the antenna
> over the vhf comm range?
>
>
> Bob . . .
>
>
>
>
Message 15
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Subject: | Re: COM radio/intercom wiring problem... |
Yes, my ammeter is the Vans ammeter.
My airplane is an RV-9A. My COM antenna is mounted on the bottom of the airplane,
approximately under where the left leg of the pilot is when sitting in the
airplane. The antenna is from Delta Pop Aviation. The coax cable is RG400 from
B&C.
I have not checked the VSWR on the antenna. I see your book gives some instructions
on how to do that.
The airplane is currently in my garage. Would that "focus" the RF energy more than
being out in the open?
Thanks,
Michael-
On Jul 27, 2013, at 8:32 PM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
> At 06:59 PM 7/27/2013, you wrote:
>>
>> I'm trying to chase down a problem with my Radio (Garmin SL-40) Intercom (Flightcom
403) wiring. One of the strange behaviors that I don't understand is when
I push the PTT to transmit on a common unicom frequency such as 122.7, the
ammeter pegs at -40 amps. When I transmit on one of the maintenance frequencies
such as 135.85, it only deflects negative 1-2 amps. But the radio is transmitting,
I can hear on my handheld.
>>
>> My ammeter is a shunt type ammeter and seems to work correctly in indicating
positive (discharge) loads for other equipment. What would make it indicate
in the negative directions. This is using just the battery. i.e. engine not running.
>>
>> The situation is that I'm trying to debug my initial wiring, so the setup has
never worked.
>
>
> You didn't say but I'm betting your ammeter is
> the one Van's sells . . . minus 40 - zero - plus
> 40?
>
> I have one of those things laying around here somewhere.
> I think I reported to the List after I bought it that
> the instrument was very vulnerable to strong RF
> in the cockpit.
>
> What kind of airplane and where is your antenna
> located? Have you checked VSWR on the antenna
> over the vhf comm range?
>
>
> Bob . . .
>
>
>
>
Message 16
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Subject: | Re: two com radios |
On Jul 28, 2013, at 5:35, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
> Have you considered 1 comm radio and a hand-held?
> My flight bag always carried this constellation of
> back-ups . . . even when I was flying an A36 with
> all the goodies.
>
> http://tinyurl.com/d5mrjgh
>
> The nice thing about this line-up is that it's
> totally independent of the airplane's electrical
> system no matter which airplane
Bob,
With this setup (in your own airplane) would you recommend:
A) connecting the handheld antenna to the aircraft com antenna (if so, how? Dave
mentioned in a previous post a that you had a setup specifically designed for
that with what sounded like an antenna splitter, but I could not find details
on your website)
B) wiring the PTT and Rx/Txs of the handheld through the audio panel as com2 (if
there is a simple way to do this, not sure... But the idea would be that the
handheld functions exactly like a normal com2).
Sacha
Message 17
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Subject: | Re: two com radios |
Sorry I just realized that John does not need/want an audio panel, I didn't mean
to high jack the thread...
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