Today's Message Index:
----------------------
1. 12:06 AM - Re: Regulator trouble? Probable resolution (Ed)
2. 12:46 AM - Loadmeter vs Battery Ammeter? (Deems Davis)
3. 07:17 AM - Re: Loadmeter vs Battery Ammeter? (Robert L. Nuckolls, III)
4. 08:16 AM - Fusible Link Connector (Bill Schlatterer)
5. 09:06 AM - VOR/GS Antenna ()
6. 09:13 AM - The importance of "good" numbers . . . (Robert L. Nuckolls, III)
7. 09:35 AM - Re: VOR/GS Antenna (Richard Dudley)
8. 10:06 AM - Re: Fusible Link Connector (Robert L. Nuckolls, III)
9. 10:13 AM - Re: Low Voltage plus Alt Loadmeter (Deems Davis)
10. 10:52 AM - Re: VOR/GS Antenna (earl_schroeder@juno.com)
11. 03:37 PM - Re: VOR/GS Antenna (Robert Feldtman)
12. 05:25 PM - Re: VOR/GS Antenna (BobsV35B@aol.com)
13. 11:13 PM - RTV sealants (Harold Kovac)
Message 1
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Subject: | Re: Regulator trouble? Probable resolution |
I've been e-mailing with Tim over at B and C (very helpful guy) and
here's what I just sent him:
Howdy Tim,
I checked it out using your troubleshooting guide. Results:
Resistance from batt neg to pin 7 0.0 - 0.1 ohms batt to
engine case 0.0 - 0.1 ohms
Buss volts 12.42 volts
Pin 3 12.33 - 12.40 v (several measurements)
Pin 6 12.07 v
Pin 4 11.02 v
Field terminal 10.86 v
B lead 12.42 v
Everything seemed pretty nominal until I was trying to get a probe into
the field connector on the alternator where I noticed the field wire
looking a little frayed. A very small tug removed it entirely. The wires
had no support for the insulation, just the crimp on the wire itself
which is where it broke.
My theory: The connection would intermittently not conduct too well
and the output voltage on the B lead would drop. The regulator would
respond by pushing the field voltage up and when the connection got
better again, the alternator output voltage would surge in response to
the high field voltage and trip the OVM. Logical?
I put some heat shrink on the wires to give them some support and
reassembled. Started but not yet flown. I expect that the problem is
solved. Time will tell. If inflight voltage stabilizes at less than
14.4, I guess I'll have to crawl under the panel and reset it. What's
the ideal voltage for charging an RG battery?
Thanks for help.
Ed Holyoke
Thanks for all the advice. If it misbehaves again, I'll let y'all know.
Robert L. Nuckolls, III wrote:
> <nuckollsr@cox.net>
>
> At 12:18 PM 6/18/2007 -0400, you wrote:
>
>>
>> I have a slightly different take on this as it seems there might
>> already be some clues here.
>>
>> Shouldn't the field voltage go above 8 volts when the alternator is
>> loaded on the ground. If it is putting out less that 14.4 volts at
>> low rpm - why isn't the field voltage up around 12 or 13? High
>> resistance somewhere in the field?
>
>
> The voltage will go that high only if one approaches the alternator's
> maximum available output current for that RPM. In this case, he cites
> a 17A load and ramp idle RPM.
>
>> Next I'd want to know why 14.7 volts while taxiing in. Is the
>> regulator voltage going up when it is hot? Does it not throttle back
>> far enough under light load? Is there a connection that is high
>> resistance when hot such that the regulator is sensing 14.4 but
>> putting out 14.7 upstream where the voltmeter is located? Or is it an
>> inaccurate voltmeter?
>
>
> There's a ton of variables which can stack up to push the setpoint
> around a bit . . . what we're interested in finding is an instability
> that accounts for the nuisance trip of an OV protection system set to
> operate at 16.2 volts or so.
>
>
>> If the connections have already been checked, I'd be tempted to
>> temporarilly wire in a cheap regulator and see what happens.
>
>
> A cheap regulator wouldn't have the ov protection built in. It
> WOULD be a useful experiment to temporarily wire in a substitute
> regulator and a separate OV sensor. I think I've got some hardware
> laying around we can send him if we don't see something really
> profound . . . or he's unable to observe a field and bus voltage
> surge associated with the nuisance trip.
>
> Bob . . .
>
>
Message 2
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Subject: | Loadmeter vs Battery Ammeter? |
Warning this question is posed by an electron nerd....
I'm planning the installation of probes & sensors for a Z14
architecture. The Z-14 Figures in the 'Connection' seem to depict the
shunts placed for use as 'loadmeters' i.e. they are placed on the
Alternator B lead (which will measure Alt charging only). In reviewing
Bob's notes. He favors a Battery Ammeter, the rationale seems to be that
it measures both charging and discharging of the battery/s. This seems
desirable to me.
However, I'm stumped as to where to locate the Shunts in the Z-14 so as
to be able to connect Battery ammeters.
How about some help?
Deems Davis
Message 3
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Subject: | Re: Loadmeter vs Battery Ammeter? |
At 12:41 AM 6/19/2007 -0700, you wrote:
>
>Warning this question is posed by an electron nerd....
>
>I'm planning the installation of probes & sensors for a Z14 architecture.
>The Z-14 Figures in the 'Connection' seem to depict the shunts placed for
>use as 'loadmeters' i.e. they are placed on the Alternator B lead (which
>will measure Alt charging only). In reviewing Bob's notes. He favors a
>Battery Ammeter, the rationale seems to be that it measures both charging
>and discharging of the battery/s. This seems desirable to me.
The Z-figures represent the latest thinking with respect
to the optimal solutions. The chapter on electrical instrumentation
was written a long time ago and will be updated at revision 12. If you have
only one electrical system monitor, it should be a low voltage
warning light. If you add anything on top of that, I'd recommend
an expanded scale voltmeter on the e-bus and/or alternator
loadmeter(s) . . . but both of those are only small peeks at a variety
of test points you'll need to look at for diagnosis. Ammeters
and voltmeters are poor monitoring tools. And as diagnostic
tools, they are only a part of what's necessary for troubleshooting.
>However, I'm stumped as to where to locate the Shunts in the Z-14 so as to
>be able to connect Battery ammeters.
What kind of panel displays are you considering? If they're
steam-gages, then they'll likely use shunts but if they're
electronic displays, they'll most likely come with hall-effect
sensors. Hall sensors can be place ANYWHERE in the system that
you think is most useful to you for knowing how many electrons
per second are passing that point . . . however, adding shunts
in series with the battery as suggested in Chapter 7 is based
on wobbly logic and poor practice. However, a hall-sensor can
certainly be placed on a battery lead if you so choose.
A caveat on battery lead hall-sensors. When the starter hits the
battery with an inrush current of as much as 1000 amps, the magnetic
forces impressed upon the hall sensor are, shall we say, significant.
The hall sensor MUST (by certain pesky laws of physics) be fitted
with a core material that serves to restrain the field flux around
the wire and supply a proportional sample of that field to the
hall device. EVERY magnetic material has a retentivity value . . .
a measure of permanent "set" that the core material will take
on when excited by an extra-ordinary force.
Depending on the materials used in your hall sensor, the act
of starting the engine can cause a small but significant
semi-permanent "set" of the field flux in the core. This
will manifest itself as what is known as "offset" . . .
a fixed error value that shows up most strongly when
the stimulus to be measured is zero . . . the indicator
reads something other than zero due to the core's
retentivity and influence of the starter inrush current.
Based on this expanded thinking, recommendations for ammeter
locations were revised to what you have in your hands today.
Without knowing more about the specifics of any hall-sensor
that may be supplied to you, I cannot recommend that they
be used as battery ammeters EXCEPT where you avoid running
starter current through the conductors. This means backtracking
to the architecture common in 1965 C-172.
The best I know how to do at the moment suggests that active
notification of low volts is #1. A voltmeter on the e-bus
(gas gage for battery during alternator out operations) is
#2. Items 3 and higher have little or no significance in
the OPERATION of your airplane . . . so sprinkle sample
and display items about your electrical system as you see
fit and you budget allows. Just understand that items 3
and higher offer no useful functions in flight and there
won't be enough of them to do a detailed troubleshooting
study on the ground.
Bob . . .
Message 4
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Subject: | Fusible Link Connector |
Is there any reason that you shouldn't use a soldered connection instead of
an inline connector in a fusible link? Would the solder go before the wires
unlike the solid inline connector? It would just make it a little cleaner
looking.
Thanks Bill S
7a Z13/8/30/32
Message 5
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Can anyone explain why some VOR "cat whisker" antennas are mounted with the
open end of the 'V' facing forward and some facing aft? Is there a
difference in reception quality and/or drag characteristics? Secondly, is
the polyester lamination over the steel for improved precipitation static
protection worth an extra $60? Thanks for any answers posted.
TPackard
--- http://USFamily.Net/dialup.html - $8.25/mo! -- http://www.usfamily.net/dsl.html - $19.99/mo! ---
Message 6
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Subject: | The importance of "good" numbers . . . |
I've often cited a simple-idea proffered by one Lord Kelvin
http://www-groups.dcs.st-and.ac.uk/~history/Printonly/Thomson.html
of whom it might be said, "Was obsessed with the ideas behind
accurate measurement." One of my favorite Kelvin quotes:
"I often say that when you can measure what you are
speaking about, and express it in numbers, you know
something about it; but when you cannot measure it,
when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind. It may be the
beginning of knowledge, but you have scarcely, in
your thoughts, advanced to the stage of science, whatever
the matter may be." - Lord Kelvin
We all have at least a rudimentary appreciation for the value
of having accurate numbers to describe the function of our
aircraft. One can easily deduce the potential for expense
and/or hazard if an airspeed indicator is badly out of
calibration . . . or perhaps an altimeter, a gyro, etc.
In many cases, the gathering and consideration of poor numbers
can have an incomprehensible effect on the lives and
fortunes of millions. This is especially true when pseudo-scientists
come to the attention of legislators and craft law based on
poor interpretation of poor numbers. With these thoughts in mind,
consider the facts and ideas presented at:
http://www.norcalblogs.com/watts/weather_stations/
There are folks belabored of the assumption that data from
these weather stations (and no doubt MANY more like them)
is accurate to within a tenth of a degree. What do you think?
Something to arm yourself with should you have a chance
to speak to your own representatives who may be inclined
to bring the force of law down upon your future and that
of your children.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 7
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Subject: | Re: VOR/GS Antenna |
TPackard,
I have been told that the orientation is a matter of preference though
the reception pattern ahead is slightly better with the tips pointing
forward. I think many prefer the appearance with the tips pointing aft.
(looks more aerodynamic:)
Richard Dudley
-6A flying (with tips pointing aft)
jtpackard@usfamily.net wrote:
>
> Can anyone explain why some VOR "cat whisker" antennas are mounted
> with the open end of the 'V' facing forward and some facing aft? Is
> there a difference in reception quality and/or drag characteristics?
> Secondly, is the polyester lamination over the steel for improved
> precipitation static protection worth an extra $60? Thanks for any
> answers posted.
> TPackard
>
>
> --- http://USFamily.Net/dialup.html - $8.25/mo! --
> http://www.usfamily.net/dsl.html - $19.99/mo! ---
>
>
Message 8
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Subject: | Re: Fusible Link Connector |
At 10:14 AM 6/19/2007 -0500, you wrote:
>Is there any reason that you shouldn't use a soldered connection instead
>of an inline connector in a fusible link? Would the solder go before the
>wires unlike the solid inline connector? It would just make it a little
>cleaner looking.
Food for thought. I think I'd want to test this.
You wouldn't want the joint to melt and then become
an intermittent connection with a potential for
a "soft fault" energy dump.
You can test this. Make up some assemblies and
then use them to fault a car battery. See where
the circuit opens first.
Bob . . .
Message 9
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Subject: | Re: Low Voltage plus Alt Loadmeter |
THANK YOU sooo much for responding and for the additional information,
I've replied where appropriate below and asked an additional question
for some clarification.
Robert L. Nuckolls, III wrote:
> <nuckollsr@cox.net>
>
> At 12:41 AM 6/19/2007 -0700, you wrote:
>
>> <deemsdavis@cox.net>
>>
>> Warning this question is posed by an electron nerd....
>>
>> I'm planning the installation of probes & sensors for a Z14
>> architecture. The Z-14 Figures in the 'Connection' seem to depict the
>> shunts placed for use as 'loadmeters' i.e. they are placed on the
>> Alternator B lead (which will measure Alt charging only). In
>> reviewing Bob's notes. He favors a Battery Ammeter, the rationale
>> seems to be that it measures both charging and discharging of the
>> battery/s. This seems desirable to me.
>
>
> The Z-figures represent the latest thinking with respect
> to the optimal solutions. The chapter on electrical instrumentation
> was written a long time ago and will be updated at revision 12. If
> you have
> only one electrical system monitor, it should be a low voltage
> warning light.
I have the LR-3's from B&C which drive/include Low Voltage indicators.
> If you add anything on top of that, I'd recommend
> an expanded scale voltmeter on the e-bus and/or alternator
> loadmeter(s) . . . but both of those are only small peeks at a variety
> of test points you'll need to look at for diagnosis. Ammeters
> and voltmeters are poor monitoring tools. And as diagnostic
> tools, they are only a part of what's necessary for troubleshooting.
>
>> However, I'm stumped as to where to locate the Shunts in the Z-14 so
>> as to be able to connect Battery ammeters.
>
> What kind of panel displays are you considering?
I have dual glass panels (EFIS) w a glass back-up. The Engine Interface
unit is a JPI product (black box) which captures information from probes
and sensors, it relies on Shunts for AMP meter input. The information
from the EIU black box is interpreted and displayed on graphic
indicators on a display page with the EFIS units.
> If they're
> steam-gages, then they'll likely use shunts but if they're
> electronic displays, they'll most likely come with hall-effect
> sensors. Hall sensors can be place ANYWHERE in the system that
> you think is most useful to you for knowing how many electrons
> per second are passing that point . . . however, adding shunts
> in series with the battery as suggested in Chapter 7 is based
> on wobbly logic and poor practice. However, a hall-sensor can
> certainly be placed on a battery lead if you so choose.
>
> A caveat on battery lead hall-sensors. When the starter hits the
> battery with an inrush current of as much as 1000 amps, the magnetic
> forces impressed upon the hall sensor are, shall we say, significant.
> The hall sensor MUST (by certain pesky laws of physics) be fitted
> with a core material that serves to restrain the field flux around
> the wire and supply a proportional sample of that field to the
> hall device. EVERY magnetic material has a retentivity value . . .
> a measure of permanent "set" that the core material will take
> on when excited by an extra-ordinary force.
>
> Depending on the materials used in your hall sensor, the act
> of starting the engine can cause a small but significant
> semi-permanent "set" of the field flux in the core. This
> will manifest itself as what is known as "offset" . . .
> a fixed error value that shows up most strongly when
> the stimulus to be measured is zero . . . the indicator
> reads something other than zero due to the core's
> retentivity and influence of the starter inrush current.
>
> Based on this expanded thinking, recommendations for ammeter
> locations were revised to what you have in your hands today.
OK, so I've got the low voltage indicators, and If I go ahead and
install the shunts per the Z-14 to supply Alternator loadmeters, I'm not
sure I understand how to interpret the information that I receive from
the Alternator loadmeters. What would this information be telling me? If
I understand it correctly (?) it would display the current that is being
output from the Alternator, correct? But if I understand correctly it
doesn't tell me that the battery is charging, (Is this what you mean
when you say that items 3 and higher have little or no significance in
Operations? can you illuminate?
> Without knowing more about the specifics of any hall-sensor
> that may be supplied to you, I cannot recommend that they
> be used as battery ammeters EXCEPT where you avoid running
> starter current through the conductors. This means backtracking
> to the architecture common in 1965 C-172.
>
> The best I know how to do at the moment suggests that active
> notification of low volts is #1. A voltmeter on the e-bus
> (gas gage for battery during alternator out operations) is
> #2. Items 3 and higher have little or no significance in
> the OPERATION of your airplane . . . so sprinkle sample
> and display items about your electrical system as you see
> fit and you budget allows. Just understand that items 3
> and higher offer no useful functions in flight and there
> won't be enough of them to do a detailed troubleshooting
> study on the ground.
>
Trying to become less of an electron nerd
Deems Davis
RV-10
http://deemsrv10.com/
Message 10
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Subject: | Re: VOR/GS Antenna |
I heard once that the forward facing whiskers were to protect the eyes
of the public [and unaware pilots]...
Can anyone explain why some VOR "cat whisker" antennas are mounted with
the
open end of the 'V' facing forward and some facing aft? Is there a
difference in reception quality and/or drag characteristics?
Message 11
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Subject: | Re: VOR/GS Antenna |
shouldnt matter - precip/icing might be an issue/ appearance probably drives
it. main thing is it should be horizontally polarized while the comm
antennas should be vertically polarized
bobf
W5RF
On 6/19/07, jtpackard@usfamily.net <jtpackard@usfamily.net> wrote:
>
>
> Can anyone explain why some VOR "cat whisker" antennas are mounted with
> the
> open end of the 'V' facing forward and some facing aft? Is there a
> difference in reception quality and/or drag characteristics? Secondly, is
> the polyester lamination over the steel for improved precipitation static
> protection worth an extra $60? Thanks for any answers posted.
> TPackard
>
>
> --- http://USFamily.Net/dialup.html - $8.25/mo! --
> http://www.usfamily.net/dsl.html - $19.99/mo! ---
>
>
Message 12
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Subject: | Re: VOR/GS Antenna |
Good Evening bobf and TPackard,
May I suggest that consideration be given to using blade antennas?
I have installed several sets with excellent results. They are relatively
low drag, handle precipitation well, have no issues with ice and nobody has
ever gotten an eye poked out by running into one.
While reception strength and pattern are not very important with modern
radios, the blades do provide excellently balanced reception throughout the
operating range. I generally have fed two VHF navigation receivers and two glide
slope receivers from one set of blades. All in all, very happy with the
results.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
In a message dated 6/19/2007 5:41:02 P.M. Central Daylight Time,
bobf@feldtman.com writes:
shouldnt matter - precip/icing might be an issue/ appearance probably drives
it. main thing is it should be horizontally polarized while the comm
antennas should be vertically polarized
bobf
W5RF
On 6/19/07, _jtpackard@usfamily.net_ (mailto:jtpackard@usfamily.net)
<_jtpackard@usfamily.net_ (mailto:jtpackard@usfamily.net) > wrote:
--> AeroElectric-List message posted by: <_jtpackard@usfamily.net _
(mailto:jtpackard@usfamily.net) >
Can anyone explain why some VOR "cat whisker" antennas are mounted with the
open end of the 'V' facing forward and some facing aft? Is there a
difference in reception quality and/or drag characteristics? Secondly, is
the polyester lamination over the steel for improved precipitation static
protection worth an extra $60? Thanks for any answers posted.
TPackard
************************************** See what's free at http://www.aol.com.
Message 13
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As far as sealants are concerned, wouldn't shoe goo, Plumbers Goop or RV
Goop from eclectic products work as well? I remember Bob talking about Shoe
Goo and some other similar products. These I believe are all from eclecti
products in LA. I purchased mine at Home Depot...seem to work well.
Harold
----- Original Message -----
From: "bob mackey" <n103md@yahoo.com>
Sent: Monday, June 18, 2007 9:51 PM
Subject: AeroElectric-List: RTV sealants
>
> There were several recent recommendations for the use of
> RTV (room temperature vulcanizing) elastic sealants.
> Before putting this stuff near your airframe or avionics,
> you should know that there are many different types of RTV,
> and most of them are somewhat corrosive as a result of the
> acetic-acid curing chemistry (smells like vinegar).
>
> For mounting antennas to aluminum airframes, consider using an
> alcohol-cure RTV such as clear or gray Dow Corning 3145, white
> General Electric RTV 162 or gray high strength RTV 167, or clear
> Loctite 5140.
>
> These alcohol-cure RTVs are more expensive.
> Instead of a buck or three, McMaster sells the GE 162 for $12.66
> per 2.8 oz tube.
> http://www.mcmaster.com (part number 74935A65, page 3305)
> The Dow 3145 is quite a bit more expensive than that.
>
> references:
> http://www.logwell.com/tech/servtips/RTV.html
> http://www.mgchemicals.com/downloads/appguide/appguide0205-1.pdf
> http://www.mgchemicals.com/products/silicones/cureguide-1part.html
> ... and of course Google...
>
>
>
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