Today's Message Index:
----------------------
1. 01:14 AM - Re: Re: Tach source for EIS (John Swartout)
2. 04:27 AM - Re: Silicone and O2 sensor? (Ronald J. Parigoris)
3. 06:39 AM - overvoltage protection false trigger fix (Ken)
4. 08:55 AM - Connector Selection Redux (Robert L. Nuckolls, III)
5. 09:20 AM - Re: Silicone and O2 sensor? (Robert L. Nuckolls, III)
6. 09:40 AM - Re: "P" lead length (Robert L. Nuckolls, III)
7. 11:03 AM - Re: Silicone and O2 sensor? (Ed Anderson)
8. 11:29 AM - Re: Silicone and O2 sensor? (Ken)
9. 12:32 PM - Re: Silicone and O2 sensor? (AI Nut)
10. 12:35 PM - Re: Silicone and O2 sensor? (AI Nut)
11. 01:15 PM - Re: Silicone and O2 sensor? (Ed Anderson)
12. 01:30 PM - Re: Slow starter (Charlie England)
13. 01:58 PM - Re: Slow starter (Robert L. Nuckolls, III)
14. 03:47 PM - P/N, source for microphone? (John Swartout)
15. 05:07 PM - Re: P/N, source for microphone? (Larry McFarland)
16. 05:28 PM - Re: P/N, source for microphone? (Bill Maxwell)
17. 06:25 PM - Re: P/N, source for microphone? (John Swartout)
18. 07:39 PM - HOT fuel guage (Jack Eckdahl)
19. 08:24 PM - Re: P/N, source for microphone? (Robert L. Nuckolls, III)
20. 08:34 PM - Re: HOT fuel guage (Robert L. Nuckolls, III)
21. 09:15 PM - Z13 and switches ()
22. 10:12 PM - Re: P/N, source for microphone? (Bill Maxwell)
Message 1
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| Subject: | Re: Tach source for EIS |
--> AeroElectric-List message posted by: "John Swartout" <jgswartout@earthlink.net>
Wow, George, thanks for the tutorial!
When I ordered the EIS from GRT, they told me I could take tach input
from the electronic ignitions, and use a switch to switch between them,
but it did not occur to me at the time to ask why I would want to.
I confess I haven't yet read the manual for the EIS. I have read some
manuals for other gadgets I'm installing, and generally find the better
ones awful and the worse ones utterly useless. Goes for computers as
well.
I'm working on the electrical system now and trying to order everything
I still need so I can cut correct size & number of holes in the
instrument panel in preparation for painting, next month if all goes
well.
Thanks for the help.
John
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
gmcjetpilot@yahoo.com
Subject: AeroElectric-List: Re: Tach source for EIS
--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
John:
"George, does that UMA tack drive convert mechanical to electronic to
supply the EIS?"
John, 5 volt (4.8v) excitation is common for many sensors for electronic
engine monitors, and this is not just limited a hall effect tach sender.
(Note sender, probe, transducer and sensor all mean the same thing for
this discussion).
5 VOLTS IS STANDARD FOR ELECTRONIC ENGINE MONITORS:
EIS has its own 5 volt output power supply (actually 4. 8 volts) to
drive the sensors or probes that require it. It may sound odd but some
of the EIS probes work on +4.8 volt bias, not ground or 12 or 14 volts.
In fact 12-14 volt going into any of the EIS probe input lines will
damage the unit.
If you read the manual for the EIS the optional or auxiliary inputs for:
fuel flow, capacitive fuel level probes , fuel pressure and hall effect
amp probe all require 4.8v to power them.
HALL EFFECT:
The hall effect tach sender converts the rotation of the tach drive into
an electrical pulse. That pulse is what the EIS is set up to measure and
turn into RPM. The standard way to get a pulse is off the magneto
p-lead, lighting or ignition coil (like on a rotax) or magnetic tach
sensor. Some of these produce their own voltage, others like a hall
effect sender need a small voltage to give the proper output.
Basics of Hall effect involve magnetic fields and electrical currents.
The hall effect needs a little input voltage to work. The UMA is a "Hall
Effect" device. Here is link explaining how "hall effect" works if you
want to know:
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/hall.html
GRT's EIS 4000:
The EIS works on +4.8 Volt Bias for many input signals.
4.8 Volts is the MAX volts input on any probe input for the EIS. 5
volts is common power supply level at the sub-component electronics
level, by the way.
Once you buy the EIS4000 and the hall effect device and read the
installation manual it will be obvious.
Even the optional amp sender GRT sells is a hall effect device and
requires a positive 4.8 volt input. The nice part of a hall effect amp
probe is the wire passes thru a coil with out a need to make a break in
the wire. The hall effect amp sensor measures the magnetic field and
converts it into a bias voltage your EIS can read. Cool.
The EIS for the most part simply measures steady state voltage levels
from a probe. With the software (and scale factor), it displays the
correct value for you to read, like: fuel pressure oil temp, EGT, CHT,
fuel level, etc.
(EGT and CHT probes produce their own (very small) voltage. The oil
pressure is set up to a ground bias and requires no external excitation
voltage. Other probes like the fuel pressure requires an excitation
voltage.)
Some of the probe inputs are self powered (EGT/CHT) and others in the
EIS are designed to measure a ground bias (oil pressure).
Some EIS inputs measure a pulse (tach and fuel flow). It sounds odd or
confusing I know, but it is super easy to connect. The wires are color
coded. The EIS know what to do.
As far as the Tach and the EIS, GRT does not sell tach transducers and
expects you to provide a pulse. The software has user settings to adjust
the number of pulses per engine revolution to account for different
input sources from 0.5 to 12. How you get the pulse is your business but
it must not be higher than 4.8 volts. IF using a coil or p-lead off a
magneto you need to add resistors.
The fuel flow requires the 4.8 volt excitation and the tach may or may
not depending on the way you are measuring it.
A pulse is a simple 0 to 5v signal that last a few Milli seconds. The
rate of this pulse is read buy the EIS and converted to the proper
display value to read as RPM or Gal/Hr. Regardless of the pulse the max
magnitude of the pulse can not exceed 4.8 volts.
Good Luck, George
Time: 05:46:10 AM PST US
From: "John Swartout" <jgswartout@earthlink.net>
Subject: RE: AeroElectric-List: Re: Tach source for EIS
--> AeroElectric-List message posted by: "John Swartout"
<jgswartout@earthlink.net>
George, does that UMA tack drive convert mechanical to electronic to
supply the EIS? 5 volts is sort of odd. How do you supply 5 volts to
yours?
I'll be using toggle switches per Z13-8 for the Pmags, so can turn off
either one at any time.
John
---------------------------------
Message 2
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: "Ronald J. Parigoris" <rparigor@suffolk.lib.ny.us>
Hello Paul
Do not archive
"Would the O2 sensor likely to be damaged by 100 low lead ?"
If a O2 sensor were used to control FI, it would be rendered unusable in a very
short
time if using 100LL.
I have no first hand experience, but after researching it seems to drive a monitor
it
will work for some time. Supposedly you will see reaction time slow down which
is moot
on a monitor. Supposedly when you first start and a sensor has deteriorated, it
will not
cycle the full scale range, and just keep getting worst.
Folk I questioned seem to think on a exclusive 100LL diet, somewhere between 50
and 250
hours, all indicated when it begins to go south, it is very recognizable and will
still
be somewhat useful even in deteriorated state.
Ron Parigoris
Message 3
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| Subject: | overvoltage protection false trigger fix |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
I had a false OVM trip thing going on similar to Tom Johnson and I
really get annoyed when simple circuits misbehave. Both of my homemade
OVM's would trip their 2.5 amp C/B on battery power without the engine
running when various switches were operated. I couldn't make anything
trip when the OVM's were disconnected and I do have diodes on all the
relays. This is on a modified Z-14 and it turns out that my OVM's are
constructed according to reivision B 6/29/04 with that detailed
explanation of the circuit.
If I removed the main battery or it's B-lead fuse then just turning on
the crossfeed would trip both OVM's almost everytime. Interestingly both
C/B's are in series with a 10 amp ATO fuse and despite many dozens of
2.5 amp C/B trips I've yet to pop a 10 amp fuse. I did not see anything
unusual with an analog scope although on the bench the scope sure shows
how the diodes across the relays eliminates the negative spike when the
relays are opened. The OVM's seemed to check out fine on my bench and
and in fact I was only been able to get one unrepeatable false trip on
the bench and that was by drawing a little arc for quite some time in
the connection to the relay coil.
I then started thinking that maybe this really is the dv/dt effect on
the SCR due to voltage spikes on the bus. So I disconnected the
tranistor from the SCR gate but no false triggering occurred which I
think that means that the dv/dt effect was NOT occurring. However while
investigating (poking around) I noticed that just touching a digital
voltmeter probe to point C (the zener) would often trigger the little
devil. That didn't seem right so I added a 10 uF aluminum cap to
stabilize/filter the 12 volt reference provided by the zener. (No
particular reason for 10 uF , I just happened to put my hand on one)
Well happy days, it seems to have done the trick as so far I have not
been able to false trip the device.
Bob I'm going to declare my problem fixed unless you still want to see
one of these OVM's for your own tests. Maybe my particular zeners are
slow learners but it seems to me that the voltage reference probably
should have a capacitor on it to reduce its sensitivity to bus
variations and in any event, that seems to have fixed my problem :)
thanks
Ken
Robert L. Nuckolls, III overvoltage protection wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
overvoltage protection
>
>At 02:34 PM 7/15/2005 -0400, you wrote:
>
>
>
>>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>>
>>Hi Bob
>>
>>It's obvious that you are a busy man and I thank you for your
>>observations. No this is not a 40amp breaker. It's a small automotive
>>relay with 40 amp rated contacts. It provides an OV disconnect for a 20
>>amp PM alternator. The relay coil draws about 130 ma. The circuit
>>breaker that feeds this relay coil, and that the Crowbar OVP trips, is
>>a 2 1/2 amp (two and a half amp) breaker.
>>
>>The OVP is not from B&C. It is homemade according to the revision dated
>>4/16/2 and constructed with the recommended Digi-key parts. Since you
>>have confirmed that this is unexpected behaviour, I will do some more
>>investigation and let you know what I find.
>>
>>This is on a modified Z-14 and it is not even on the battery that feeds
>>the primary systems of my electrically dependant engine. This battery
>>and PM alternator feeds the backup engine systems. I'll start by
>>investigating whether the OVP for the other alternator behaves similarly
>>and perhaps put a scope on the 22 uF capacitor and the SCR. If I don't
>>learn anything useful and it is still exhibiting this behaviour, I'll be
>>happy to donate it to the cause if you still want to see it but it is
>>just a homemade unit.
>>
>>
>
> Yes. Send it to me. First, I'll test it for performance
> and then perhaps I'll make some mods and return it to
> see if it makes any difference.
>
> Bob . . .
>
>
Message 4
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| Subject: | Connector Selection Redux |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 01:22 AM 7/24/2005 -0400, you wrote:
Bob,
'Way back when, you discoursed upon the choices for connectors -
DSub/Molex - on the temporary address of:
"http://216.55.140.222/temp/power_dist.jpg"
I wonder whether it was lost when you settled on the new address or
whether it was incorporated in a neewer article. I have just lost the
original and beg to acquire it in whatever form it now takes.............
Cheers,
Ferg Kyle
VE3LVO@rac.ca
The ip address was a temporary archive for aeroelectric.com
articles when we were having server troubles. The link you've
cited now resides with a supplementary image at:
http://www.aeroelectric.com/Pictures/D-Sub_Power_Dist_1.jpg
and
http://www.aeroelectric.com/Pictures/D-Sub_Power_Dist_2.jpg
and it's a description of a power distribution assembly
I designed for a military program wherein I demonstrated
a technique for running a LOT of current through a d-sub
connector. In this case, pathways rated at 20A continuous.
This was accomplished by PARALLELING 5A pins and using
lengths of wire to provide BALLASTING resistance that
would wash out variability in pin-to-pin contact resistance.
I dug into the archives and found the conversation that
prompted my response and attached a copy below:
>
>Bob and Gang,
>Discussion of connectors raises an interesting thought; don't think
>I've never seen a good article on multi-wire plug connectors, and the
selection of
>a particular type for a particular application. Electronics guys know the
>details because they've worked with them for years. The rest of us pick up a
>Digi-Key catalog or similar, find a jaw-dropping selection, and groan.
Engineers navigating connector-wilds aren't much happier about it.
Connectors are like laundry soap . . . so many choices, so few
outstanding reasons for selecting any particular technology.
Every year or so, some starry-eyed sales rep would drop a new
connector catalog on my desk claiming that THIS product finally
answered the needs for everyone and was the greatest connector
since they began slicing bread . . .
Task 1 for a connector is to make non-permanent connections
between one or more strands of wire. Attachment to the wire
can be solder, crimp, or mass-termination (like ribbon cables
munched onto a 50 wires in a single stroke). Considerations
are (1) do you really NEED a connector there? (2) how many strands
of wire? (3) what sizes of wire? (4) any extraordinary
environmental concerns? (5) any extra ordinary mechanical
concerns?
> Need examples? When does one use a Molex connector vs a D-sub?
D-subs are the first connector I consider for any new application.
Check out this picture:
(see corrected link above)
This is a "tall" picture . . . so scroll down to
see the bottom half.
This is an all solid state, power distribution
box that routes energy from ground power jack
and up to two batteries to 5 different busses
in the vehicle. External power input can be as
high as 40A continuous . . . yet, if one knows
how to make it work, all can be handled though
the 20AWG pins of d-sub connectors.
This box USED to be about 10" long, 4" thick
5" wide, full of relays and wired up with
supper-whizzy connectors. The connectors alone
on the previous version cost more than the whole
bill of materials for the new version.
Here you can see how the solder-right-to-
the-board features of D-sub connectors has
a profound reduction of labor to install.
In this case, although subjected to up to
30g acceleration and short term radiant
heating, the D-sub was entirely suited
mechanically to the task. The mil-spec,
gold-plated pins were no worse (or better)
than the gold-plated pins on MUCH more
expensive connectors.
> Why are (most?) D-sub pins gold plated?
I wouldn't say most . . . you can buy tin-plated
connectors in D-sub. Gold is preferred because is
does not corrode . . . electrical integrity of
mated pins is not nearly so likely to degrade
with age and use. Gold plated pins are relatively
cheap for D-subs because of the huge volume in
this particular product. By-the-way, the same
20AWG pin is used in AMP CPC Series II connectors
like:
http://dkc3.digikey.com/PDF/T031/0192.pdf
use the same pins as a D-sub . . . so you have
two low-cost connector opportunities to use the
same tools and a common part number for pins.
> Is connector selection as simple as
>observing an amperage rating, or is there more to it?
I you were wiring anything but voltages up to 28vdc,
there might be voltage rating issues but in our
market, ANY connector will suffice that can
carry the current and accommodate the quantity
of wires.
If you need to carry more than 4A continuous
per pin, consider the CPC Series I connectors
in the same catalog can accommodate up to
14AWG wires. Except for firewall penetrations,
the AMP CPC connectors for systems teamed with
CPC and/or D-subs for avionics would be my
connectors of choice. They are low cost, tools
are reasonably priced, gold plated pins are
available for both styles. Excellent values
for our projects.
> Why a choice of metal or plastic backshells?
Plastic is less expensive and lighter. 90% of my
applications use plastic. There are almost never
interference issues that justify the metal or
conductive plastic backshells. If the connector
is used under the cowl, metal backshells are probably
advised.
> The automotive world uses plastic connector shells
>that lock when mated; why don't we use similar connectors in our airplanes?
>Or do we, and where do you get them?
Mate-n-Lock/Molex style connectors have been used
on many single engine airplane beginning in the 60's.
>Does a Molex shell offer any wire support, or does it strictly
>depend on the insulation crimp of the little sheet copper pin?
That's it. No bundle support. Only the insulation grip
on each strand. I was skeptical when I first laid eyes on them
but in retrospect, they seem to have performed well for decades
in spite of no back shell support and non-gold pins.
> May seem like dumb questions to some, but...
Not at all. Before Internet access reduced the need,
my library used to have about 5 feet of shelving
dedicated to connectors. Your consternation is understandable.
I think you'll find that the two connector series
I cited will do a good job for your project 98%
of the time.
----------------------------------------------------
The short summation for the above is to consider either
D-sub, AMP CPC circular, or the white plastic connectors
like Mate-n-Lock and Molex first. None of these connnectors
is recommend to carry wires THROUGH THE FIREWALL. See other
archive articles on this issue. Further, D-sub/AMP CPC are
probably not suited for the one high-voltage application
found on light aircraft: power supply to strobe head wireing.
For the vast majority of other applications, I certainly
try to make one of these three offerings do the job before
considering any other connector technology.
Bob . . .
Message 5
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 07:21 AM 7/24/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
><rparigor@suffolk.lib.ny.us>
>
>Hello Paul
>
>Do not archive
>
>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>
>If a O2 sensor were used to control FI, it would be rendered unusable in a
>very short
>time if using 100LL.
>
>I have no first hand experience, but after researching it seems to drive a
>monitor it
>will work for some time. Supposedly you will see reaction time slow down
>which is moot
>on a monitor. Supposedly when you first start and a sensor has
>deteriorated, it will not
>cycle the full scale range, and just keep getting worst.
>
>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>between 50 and 250
>hours, all indicated when it begins to go south, it is very recognizable
>and will still
>be somewhat useful even in deteriorated state.
I saw an O2 sensor installed on a Falco some years ago wherein the
builder operated his engine on 100LL. He said that this particular
sensor had been working satisfactorily for over 400 hours.
As he explained it to me, the O2 sensor has a DC output (very small,
measured in millivolts) that is proportional to numbers of O2
molecules per second that strike the sensor. If one has a very agile
mixture control sensor that needs to know an accurate proportion
of O2 in exhaust gasses. Current O2 detector technology may not be
suitable; he acknowledged that lead present in the fuel will
alter calibration of the sensor after a few hundred hours. It was this
builder's intent to simply know when excess oxygen was present . . .
i.e. mixture too lean. His indicator was a simple analog instrument
that he used at altitude to set up cruise mixture. With the cruise rpm
and pressure, he would lean until the indicator first showed signs
of activity whereupon he would enrich ever so slightly.
Absolute calibration of the sensor was not important. He wasn't
interested in HOW MUCH O2 was present, only that it WAS
present in any amount. I believe he mentioned that his sensor cost
around $25. Given that it costs about that much to put in a couple of
spark-plugs, perhaps adding an O2 sensor to the list of time-based
preventative maintenance items would allow us to exploit this technology
to our advantage.
Bob . . .
Message 6
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| Subject: | Re: "P" lead length |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 02:18 PM 7/22/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "John Schroeder"
><jschroeder@perigee.net>
>
>Bob -
>
>Thanks for the diagram. After a good night's sleep and some study of the
>diagram, we concluded that the mags were indeed wired OK. We did
>disconnect the leads and ground shields to check for shorts. The problem
>was in the test plan!! You gotta put the meter in line and not across the
>lines!
>
>Thanks for the help.
Aha! The ol' "lying ohmmeter" syndrome. Many builders have placed
an ohmmeter across the mag switch expecting to see measurable
activity in the reading when opening and closing the switch.
Take a peek at:
http://www.aeroelectric.com/Pictures/Magneto_Resistance.gif
The mag switch turns a magneto OFF by placing a short across
the magneto's primary winding. The points and "condenser" in
the magneto are ALSO in parallel with the primary winding.
When one attempts to measure some change of resistance at
the switch end, there's a chance that the points are resting
in a closed state and there's already a dead short in parallel
with the magneto switch. Further, the resistance of the primary
winding is so low, some ohmmeters may not have sufficient
resolution in this realm of measurement to show a measurable
effect of operating the magneto switch even when the points
are open.
One can acquire a high resolution, low ohms-adapter for
their toolbox by fabricating one of the low-ohms adapters
depicted in:
http://aeroelectric.com/articles/LowOhmsAdapter_3.pdf
I published this article for technicians in the field
who have similar measurement problems working on our
aircraft. I've been getting some good feedback on the
usefulness of this easily fabricated test tool.
Bob . . .
Message 7
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: "Ed Anderson" <eanderson@carolina.rr.com>
I have flow approx 300 hours using lead gas and O2 sensors. While Lead may
render the O2 sensor sensitivity unsuitable for emission control purposes
connected to an automobile CPU, using it for air/Fuel ratio indicator sensor
will generally give me 100 + hours before it is no longer usable. The range
of the older version of the O2 sensor is 0 - 1 volt with 1 volt indicating
max rich and 0 indicating max lean - in-between those limits it is very
non-linear but can be useful once you learn to interpret the LED indicators
on the most common Air/Fuel ratio indicators..
Ed Anderson
eanderson@carolina.rr.com
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Subject: Re: AeroElectric-List: Silicone and O2 sensor?
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <nuckollsr@cox.net>
>
> At 07:21 AM 7/24/2005 -0400, you wrote:
>
>>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
>><rparigor@suffolk.lib.ny.us>
>>
>>Hello Paul
>>
>>Do not archive
>>
>>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>>
>>If a O2 sensor were used to control FI, it would be rendered unusable in a
>>very short
>>time if using 100LL.
>>
>>I have no first hand experience, but after researching it seems to drive a
>>monitor it
>>will work for some time. Supposedly you will see reaction time slow down
>>which is moot
>>on a monitor. Supposedly when you first start and a sensor has
>>deteriorated, it will not
>>cycle the full scale range, and just keep getting worst.
>>
>>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>>between 50 and 250
>>hours, all indicated when it begins to go south, it is very recognizable
>>and will still
>>be somewhat useful even in deteriorated state.
>
> I saw an O2 sensor installed on a Falco some years ago wherein the
> builder operated his engine on 100LL. He said that this particular
> sensor had been working satisfactorily for over 400 hours.
>
> As he explained it to me, the O2 sensor has a DC output (very small,
> measured in millivolts) that is proportional to numbers of O2
> molecules per second that strike the sensor. If one has a very agile
> mixture control sensor that needs to know an accurate proportion
> of O2 in exhaust gasses. Current O2 detector technology may not be
> suitable; he acknowledged that lead present in the fuel will
> alter calibration of the sensor after a few hundred hours. It was this
> builder's intent to simply know when excess oxygen was present . . .
> i.e. mixture too lean. His indicator was a simple analog instrument
> that he used at altitude to set up cruise mixture. With the cruise rpm
> and pressure, he would lean until the indicator first showed signs
> of activity whereupon he would enrich ever so slightly.
>
> Absolute calibration of the sensor was not important. He wasn't
> interested in HOW MUCH O2 was present, only that it WAS
> present in any amount. I believe he mentioned that his sensor cost
> around $25. Given that it costs about that much to put in a couple of
> spark-plugs, perhaps adding an O2 sensor to the list of time-based
> preventative maintenance items would allow us to exploit this technology
> to our advantage.
>
> Bob . . .
>
>
>
Message 8
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Such narrow band sensors are really only useful for determining rich or
lean of stoichometric. Or approximately stoich. if switching back and
forth. I'm not convinced they are terribly useful. I plan to cruise
leaner than stoich and be richer than stoich. at full power. In any
event it has been reported that the sensor life is greatly increased in
the presence of lead if it is shrouded from direct exhaust blast such as
mounting it in a crosstube. A 3 wire heated sensor might be better in a
crosstube. Output is typically 0 to 1 volt but with a sharp knee at
stoich so in essence it is really a on or off rich or lean of stoich
switch. The ten LED display units are usually based on a 3914 display
chip but they still can't provide any more information than mentioned
above. True wideband instruments with actual air/fuel ratio readout are
available nowadays for several hundred dollars as a number of vehicles
are now using wide band sensors. They are popular with automotive
tuners. But again not real long life with leaded fuel.
Ken
Robert L. Nuckolls, III wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>
>At 07:21 AM 7/24/2005 -0400, you wrote:
>
>
>
>>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
>><rparigor@suffolk.lib.ny.us>
>>
>>Hello Paul
>>
>>Do not archive
>>
>>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>>
>>If a O2 sensor were used to control FI, it would be rendered unusable in a
>>very short
>>time if using 100LL.
>>
>>I have no first hand experience, but after researching it seems to drive a
>>monitor it
>>will work for some time. Supposedly you will see reaction time slow down
>>which is moot
>>on a monitor. Supposedly when you first start and a sensor has
>>deteriorated, it will not
>>cycle the full scale range, and just keep getting worst.
>>
>>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>>between 50 and 250
>>hours, all indicated when it begins to go south, it is very recognizable
>>and will still
>>be somewhat useful even in deteriorated state.
>>
>>
>
> I saw an O2 sensor installed on a Falco some years ago wherein the
> builder operated his engine on 100LL. He said that this particular
> sensor had been working satisfactorily for over 400 hours.
>
> As he explained it to me, the O2 sensor has a DC output (very small,
> measured in millivolts) that is proportional to numbers of O2
> molecules per second that strike the sensor. If one has a very agile
> mixture control sensor that needs to know an accurate proportion
> of O2 in exhaust gasses. Current O2 detector technology may not be
> suitable; he acknowledged that lead present in the fuel will
> alter calibration of the sensor after a few hundred hours. It was this
> builder's intent to simply know when excess oxygen was present . . .
> i.e. mixture too lean. His indicator was a simple analog instrument
> that he used at altitude to set up cruise mixture. With the cruise rpm
> and pressure, he would lean until the indicator first showed signs
> of activity whereupon he would enrich ever so slightly.
>
> Absolute calibration of the sensor was not important. He wasn't
> interested in HOW MUCH O2 was present, only that it WAS
> present in any amount. I believe he mentioned that his sensor cost
> around $25. Given that it costs about that much to put in a couple of
> spark-plugs, perhaps adding an O2 sensor to the list of time-based
> preventative maintenance items would allow us to exploit this technology
> to our advantage.
>
> Bob . . .
>
>
Message 9
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: AI Nut <ainut@hiwaay.net>
If you get the wideband sensor for VW's, they're only about $40 each.
This, of course, does not include any kind of readout -- for that,
you're on you own. 8-)
David
Ken wrote:
>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
>Such narrow band sensors are really only useful for determining rich or
>lean of stoichometric. Or approximately stoich. if switching back and
>forth. I'm not convinced they are terribly useful. I plan to cruise
>leaner than stoich and be richer than stoich. at full power. In any
>event it has been reported that the sensor life is greatly increased in
>the presence of lead if it is shrouded from direct exhaust blast such as
>mounting it in a crosstube. A 3 wire heated sensor might be better in a
>crosstube. Output is typically 0 to 1 volt but with a sharp knee at
>stoich so in essence it is really a on or off rich or lean of stoich
>switch. The ten LED display units are usually based on a 3914 display
>chip but they still can't provide any more information than mentioned
>above. True wideband instruments with actual air/fuel ratio readout are
>available nowadays for several hundred dollars as a number of vehicles
>are now using wide band sensors. They are popular with automotive
>tuners. But again not real long life with leaded fuel.
>Ken
>
>Robert L. Nuckolls, III wrote:
>
>
>
>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>>
>>At 07:21 AM 7/24/2005 -0400, you wrote:
>>
>>
>>
>>
>>
>>>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
>>><rparigor@suffolk.lib.ny.us>
>>>
>>>Hello Paul
>>>
>>>Do not archive
>>>
>>>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>>>
>>>If a O2 sensor were used to control FI, it would be rendered unusable in a
>>>very short
>>>time if using 100LL.
>>>
>>>I have no first hand experience, but after researching it seems to drive a
>>>monitor it
>>>will work for some time. Supposedly you will see reaction time slow down
>>>which is moot
>>>on a monitor. Supposedly when you first start and a sensor has
>>>deteriorated, it will not
>>>cycle the full scale range, and just keep getting worst.
>>>
>>>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>>>between 50 and 250
>>>hours, all indicated when it begins to go south, it is very recognizable
>>>and will still
>>>be somewhat useful even in deteriorated state.
>>>
>>>
>>>
>>>
>> I saw an O2 sensor installed on a Falco some years ago wherein the
>> builder operated his engine on 100LL. He said that this particular
>> sensor had been working satisfactorily for over 400 hours.
>>
>> As he explained it to me, the O2 sensor has a DC output (very small,
>> measured in millivolts) that is proportional to numbers of O2
>> molecules per second that strike the sensor. If one has a very agile
>> mixture control sensor that needs to know an accurate proportion
>> of O2 in exhaust gasses. Current O2 detector technology may not be
>> suitable; he acknowledged that lead present in the fuel will
>> alter calibration of the sensor after a few hundred hours. It was this
>> builder's intent to simply know when excess oxygen was present . . .
>> i.e. mixture too lean. His indicator was a simple analog instrument
>> that he used at altitude to set up cruise mixture. With the cruise rpm
>> and pressure, he would lean until the indicator first showed signs
>> of activity whereupon he would enrich ever so slightly.
>>
>> Absolute calibration of the sensor was not important. He wasn't
>> interested in HOW MUCH O2 was present, only that it WAS
>> present in any amount. I believe he mentioned that his sensor cost
>> around $25. Given that it costs about that much to put in a couple of
>> spark-plugs, perhaps adding an O2 sensor to the list of time-based
>> preventative maintenance items would allow us to exploit this technology
>> to our advantage.
>>
>> Bob . . .
>>
>>
>>
>>
>
>
>.
>
>
>
Message 10
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: AI Nut <ainut@hiwaay.net>
Ed, I was informed that an O2 sensor that has been lead fouled could be
put back in service like new just by using a propane torch on it. Have
you tried that? Or what did you do, 3 times in those 300 hours?
Thanks,
David
Ed Anderson wrote:
>--> AeroElectric-List message posted by: "Ed Anderson" <eanderson@carolina.rr.com>
>
>I have flow approx 300 hours using lead gas and O2 sensors. While Lead may
>render the O2 sensor sensitivity unsuitable for emission control purposes
>connected to an automobile CPU, using it for air/Fuel ratio indicator sensor
>will generally give me 100 + hours before it is no longer usable. The range
>of the older version of the O2 sensor is 0 - 1 volt with 1 volt indicating
>max rich and 0 indicating max lean - in-between those limits it is very
>non-linear but can be useful once you learn to interpret the LED indicators
>on the most common Air/Fuel ratio indicators..
>
>
>Ed Anderson
>eanderson@carolina.rr.com
>
>
>----- Original Message -----
>From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>To: <aeroelectric-list@matronics.com>
>Subject: Re: AeroElectric-List: Silicone and O2 sensor?
>
>
>
>
>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
>><nuckollsr@cox.net>
>>
>>At 07:21 AM 7/24/2005 -0400, you wrote:
>>
>>
>>
>>>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
>>><rparigor@suffolk.lib.ny.us>
>>>
>>>Hello Paul
>>>
>>>Do not archive
>>>
>>>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>>>
>>>If a O2 sensor were used to control FI, it would be rendered unusable in a
>>>very short
>>>time if using 100LL.
>>>
>>>I have no first hand experience, but after researching it seems to drive a
>>>monitor it
>>>will work for some time. Supposedly you will see reaction time slow down
>>>which is moot
>>>on a monitor. Supposedly when you first start and a sensor has
>>>deteriorated, it will not
>>>cycle the full scale range, and just keep getting worst.
>>>
>>>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>>>between 50 and 250
>>>hours, all indicated when it begins to go south, it is very recognizable
>>>and will still
>>>be somewhat useful even in deteriorated state.
>>>
>>>
>> I saw an O2 sensor installed on a Falco some years ago wherein the
>> builder operated his engine on 100LL. He said that this particular
>> sensor had been working satisfactorily for over 400 hours.
>>
>> As he explained it to me, the O2 sensor has a DC output (very small,
>> measured in millivolts) that is proportional to numbers of O2
>> molecules per second that strike the sensor. If one has a very agile
>> mixture control sensor that needs to know an accurate proportion
>> of O2 in exhaust gasses. Current O2 detector technology may not be
>> suitable; he acknowledged that lead present in the fuel will
>> alter calibration of the sensor after a few hundred hours. It was this
>> builder's intent to simply know when excess oxygen was present . . .
>> i.e. mixture too lean. His indicator was a simple analog instrument
>> that he used at altitude to set up cruise mixture. With the cruise rpm
>> and pressure, he would lean until the indicator first showed signs
>> of activity whereupon he would enrich ever so slightly.
>>
>> Absolute calibration of the sensor was not important. He wasn't
>> interested in HOW MUCH O2 was present, only that it WAS
>> present in any amount. I believe he mentioned that his sensor cost
>> around $25. Given that it costs about that much to put in a couple of
>> spark-plugs, perhaps adding an O2 sensor to the list of time-based
>> preventative maintenance items would allow us to exploit this technology
>> to our advantage.
>>
>> Bob . . .
>>
>>
>>
>>
>>
>
>
>.
>
>
>
Message 11
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| Subject: | Re: Silicone and O2 sensor? |
--> AeroElectric-List message posted by: "Ed Anderson" <eanderson@carolina.rr.com>
Hi David
No, I have not tired that - I did look for a solvent that would dissolve
lead, however, had no luck. Since these were the old cheap O2 sensors
(around $25), I just replaced them. However, thanks for the idea I'll give
it a try next time the O2 sensor starts down hill. It keeps indicating, but
the high voltage end keeps getting lower. Like drops from around 1.0 volt
to around 0.8 volts which tends to compress the scale a bit which as several
folks have mentioned is not linear to begin with.
Ed
----- Original Message -----
From: "AI Nut" <ainut@hiwaay.net>
Subject: Re: AeroElectric-List: Silicone and O2 sensor?
> --> AeroElectric-List message posted by: AI Nut <ainut@hiwaay.net>
>
> Ed, I was informed that an O2 sensor that has been lead fouled could be
> put back in service like new just by using a propane torch on it. Have
> you tried that? Or what did you do, 3 times in those 300 hours?
>
> Thanks,
> David
>
>
> Ed Anderson wrote:
>
>>--> AeroElectric-List message posted by: "Ed Anderson"
>><eanderson@carolina.rr.com>
>>
>>I have flow approx 300 hours using lead gas and O2 sensors. While Lead
>>may
>>render the O2 sensor sensitivity unsuitable for emission control purposes
>>connected to an automobile CPU, using it for air/Fuel ratio indicator
>>sensor
>>will generally give me 100 + hours before it is no longer usable. The
>>range
>>of the older version of the O2 sensor is 0 - 1 volt with 1 volt indicating
>>max rich and 0 indicating max lean - in-between those limits it is very
>>non-linear but can be useful once you learn to interpret the LED
>>indicators
>>on the most common Air/Fuel ratio indicators..
>>
>>
>>Ed Anderson
>>eanderson@carolina.rr.com
>>
>>
>>----- Original Message -----
>>From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>>To: <aeroelectric-list@matronics.com>
>>Subject: Re: AeroElectric-List: Silicone and O2 sensor?
>>
>>
>>
>>
>>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
>>><nuckollsr@cox.net>
>>>
>>>At 07:21 AM 7/24/2005 -0400, you wrote:
>>>
>>>
>>>
>>>>--> AeroElectric-List message posted by: "Ronald J. Parigoris"
>>>><rparigor@suffolk.lib.ny.us>
>>>>
>>>>Hello Paul
>>>>
>>>>Do not archive
>>>>
>>>>"Would the O2 sensor likely to be damaged by 100 low lead ?"
>>>>
>>>>If a O2 sensor were used to control FI, it would be rendered unusable in
>>>>a
>>>>very short
>>>>time if using 100LL.
>>>>
>>>>I have no first hand experience, but after researching it seems to drive
>>>>a
>>>>monitor it
>>>>will work for some time. Supposedly you will see reaction time slow down
>>>>which is moot
>>>>on a monitor. Supposedly when you first start and a sensor has
>>>>deteriorated, it will not
>>>>cycle the full scale range, and just keep getting worst.
>>>>
>>>>Folk I questioned seem to think on a exclusive 100LL diet, somewhere
>>>>between 50 and 250
>>>>hours, all indicated when it begins to go south, it is very recognizable
>>>>and will still
>>>>be somewhat useful even in deteriorated state.
>>>>
>>>>
>>> I saw an O2 sensor installed on a Falco some years ago wherein the
>>> builder operated his engine on 100LL. He said that this particular
>>> sensor had been working satisfactorily for over 400 hours.
>>>
>>> As he explained it to me, the O2 sensor has a DC output (very small,
>>> measured in millivolts) that is proportional to numbers of O2
>>> molecules per second that strike the sensor. If one has a very agile
>>> mixture control sensor that needs to know an accurate proportion
>>> of O2 in exhaust gasses. Current O2 detector technology may not be
>>> suitable; he acknowledged that lead present in the fuel will
>>> alter calibration of the sensor after a few hundred hours. It was this
>>> builder's intent to simply know when excess oxygen was present . . .
>>> i.e. mixture too lean. His indicator was a simple analog instrument
>>> that he used at altitude to set up cruise mixture. With the cruise rpm
>>> and pressure, he would lean until the indicator first showed signs
>>> of activity whereupon he would enrich ever so slightly.
>>>
>>> Absolute calibration of the sensor was not important. He wasn't
>>> interested in HOW MUCH O2 was present, only that it WAS
>>> present in any amount. I believe he mentioned that his sensor cost
>>> around $25. Given that it costs about that much to put in a couple of
>>> spark-plugs, perhaps adding an O2 sensor to the list of time-based
>>> preventative maintenance items would allow us to exploit this
>>> technology
>>> to our advantage.
>>>
>>> Bob . . .
>>>
>>>
>>>
>>>
>>>
>>
>>
>>.
>>
>>
>>
>
>
>
Message 12
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| Subject: | Re: Slow starter |
--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Charlie Burton wrote:
>--> AeroElectric-List message posted by: "Charlie Burton" <notrubce@hotmail.com>
>
>I have a condition in my O-360 Glastar that puzzles me. I can turn the key switch
(Aircraft Spruce) to START and the engine starts to turn but at a slow rate
like a low battery, high compression, too small a battery cable, etc. The strange
part is that I just let go of the key and then try it again and the engine
turns over very nicely and starts on the first revolution through. I have one
mag on the left side and a Lightspeed ignition on the right. Any ideas?
>
>Charlie Burton & N331Fox
>
No particular ideas for a cure, but it's a fairly common symptom across
multiple starter types, unrelated to ignition type. I've even seen it in
cars.
Dragging solenoid plunger not driving the high current contacts firmly
together?
Charlie
Message 13
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| Subject: | Re: Slow starter |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 03:28 PM 7/24/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: Charlie England
><ceengland@bellsouth.net>
>
>Charlie Burton wrote:
>
> >--> AeroElectric-List message posted by: "Charlie Burton"
> <notrubce@hotmail.com>
> >
> >I have a condition in my O-360 Glastar that puzzles me. I can turn the
> key switch (Aircraft Spruce) to START and the engine starts to turn but
> at a slow rate like a low battery, high compression, too small a battery
> cable, etc. The strange part is that I just let go of the key and then
> try it again and the engine turns over very nicely and starts on the
> first revolution through. I have one mag on the left side and a
> Lightspeed ignition on the right. Any ideas?
> >
> >Charlie Burton & N331Fox
> >
>
>No particular ideas for a cure, but it's a fairly common symptom across
>multiple starter types, unrelated to ignition type. I've even seen it in
>cars.
>
>Dragging solenoid plunger not driving the high current contacts firmly
>together?
I'd start with a voltage measurement at the starter . . . and
in particular, is it markedly different for the first (slow)
event versus the second (faster) event.
It's unlikely to have anything to do with starter switch
or ignition syles and everything to do with loss of
conductivity somewhere along the route from battery to
starter. If possible, have someone help you and get voltage
readings at the battery at the same time as your readings
are taken at the starter.
I worked a problem with similar symptoms years ago. Voltage
reading were HIGHER while the starter was running slow than
when cranking normally. This led to the diagnosis that brushes
were hanging up in their holders and casing the starter to
draw LESS current while the problem was worst.
Bob . . .
Message 14
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| Subject: | P/N, source for microphone? |
--> AeroElectric-List message posted by: "John Swartout" <jgswartout@earthlink.net>
My Icom A200 com radio needs a microphone. I will always be using
headphones, but the manual for the radio says I should also have a
microphone, either a low-impedance carbon mike or a dynamic mike, which
requires a pre-amp. Microphone impedance is 600 ohms. As this device
will primarily be unwanted clutter in the cockpit, I would like to get
the cheapest mike that will function if ever needed. Any suggestions?
Thank you all.
John
Message 15
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| Subject: | Re: P/N, source for microphone? |
--> AeroElectric-List message posted by: Larry McFarland <larrymc@qconline.com>
John,
I use an A200 tranciever with headsets (w/built in mics) no extra
microphone.
Doubt you'd ever need it. I would delete it.
Larry McFarland
do not archive
John Swartout wrote:
>--> AeroElectric-List message posted by: "John Swartout" <jgswartout@earthlink.net>
>
>My Icom A200 com radio needs a microphone. I will always be using
>headphones, but the manual for the radio says I should also have a
>microphone, either a low-impedance carbon mike or a dynamic mike, which
>requires a pre-amp. Microphone impedance is 600 ohms. As this device
>will primarily be unwanted clutter in the cockpit, I would like to get
>the cheapest mike that will function if ever needed. Any suggestions?
>Thank you all.
>
>John
>
>
>
Message 16
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| Subject: | Re: P/N, source for microphone? |
--> AeroElectric-List message posted by: "Bill Maxwell" <wrmaxwell@bigpond.com>
When you say "headphones" do you mean "headsets" John? If so, they of
course incorporate a microphone and that is all the A200 needs to be able to
transmit your voice, once the headset is correctly wired to the A200's
phones and mic circuits. You certainly will not need, nor be able to use a
second, presumably hand operated, microphone without also installing a
switch or resorting to additional wiring.
Bill
--- Original Message -----
From: "John Swartout" <jgswartout@earthlink.net>
Subject: AeroElectric-List: P/N, source for microphone?
> --> AeroElectric-List message posted by: "John Swartout"
> <jgswartout@earthlink.net>
>
> My Icom A200 com radio needs a microphone. I will always be using
> headphones, but the manual for the radio says I should also have a
> microphone, either a low-impedance carbon mike or a dynamic mike, which
> requires a pre-amp. Microphone impedance is 600 ohms. As this device
> will primarily be unwanted clutter in the cockpit, I would like to get
> the cheapest mike that will function if ever needed. Any suggestions?
> Thank you all.
>
> John
>
>
>
Message 17
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| Subject: | P/N, source for microphone? |
--> AeroElectric-List message posted by: "John Swartout" <jgswartout@earthlink.net>
Yes, I mean "headsets." Thanks. Since there will be two headsets, it
does seem unnecessarily redundant to add a mike to the panel.. Thanks
for the tip.
John
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bill
Maxwell
Subject: Re: AeroElectric-List: P/N, source for microphone?
--> AeroElectric-List message posted by: "Bill Maxwell"
<wrmaxwell@bigpond.com>
When you say "headphones" do you mean "headsets" John? If so, they of
course incorporate a microphone and that is all the A200 needs to be
able to
transmit your voice, once the headset is correctly wired to the A200's
phones and mic circuits. You certainly will not need, nor be able to
use a
second, presumably hand operated, microphone without also installing a
switch or resorting to additional wiring.
Bill
--- Original Message -----
From: "John Swartout" <jgswartout@earthlink.net>
Subject: AeroElectric-List: P/N, source for microphone?
> --> AeroElectric-List message posted by: "John Swartout"
> <jgswartout@earthlink.net>
>
> My Icom A200 com radio needs a microphone. I will always be using
> headphones, but the manual for the radio says I should also have a
> microphone, either a low-impedance carbon mike or a dynamic mike,
which
> requires a pre-amp. Microphone impedance is 600 ohms. As this device
> will primarily be unwanted clutter in the cockpit, I would like to get
> the cheapest mike that will function if ever needed. Any suggestions?
> Thank you all.
>
> John
>
>
>
Message 18
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--> AeroElectric-List message posted by: "Jack Eckdahl" <jeckdahl@sjrwmd.com>
I have 30 hours on my RV9A. Today, after taking off, I noticed an electrical "smell".
I glanced at all my guages and noticed moisture inside the lense of the
Vans fuel gauge. It was working, but I had never noticed moisture before.
My hanger is not humidity proof, but the plane has never been wet. I reached
under the panel and noticed that the guage was extremely hot to the touch. I
landed and did my best to look behind the panel. I saw no melted or burnt wires,
but the guage was still very hot and moisture continued to be behind the
faceplate. What should I do to troubleshoot? What would cause this after 30
hours of no known problem? thanks, Jack
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com on behalf of Robert L.
Nuckolls, III
Cc:=09
Subject: Re: AeroElectric-List: "P" lead length
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 08:48 AM 7/20/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>
>Are there lengths that should be avoided when installing "P" Leads? In other
>words, are there lengths that potentially cause more "transmitted noise" . .
>. or is that an issues with shielded "P" leads?
No length issues. You DO want to ground the shield
at the engine end only . . . and I recommend you use
the shield to PROVIDE ground at the switch end make no
other connections at switch end as suggested in numerous
other texts.
Bob . . .
Message 19
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| Subject: | Re: P/N, source for microphone? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 06:45 PM 7/24/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "John Swartout"
><jgswartout@earthlink.net>
>
>My Icom A200 com radio needs a microphone. I will always be using
>headphones, but the manual for the radio says I should also have a
>microphone, either a low-impedance carbon mike or a dynamic mike, which
>requires a pre-amp. Microphone impedance is 600 ohms. As this device
>will primarily be unwanted clutter in the cockpit, I would like to get
>the cheapest mike that will function if ever needed. Any suggestions?
>Thank you all.
What they're referring to is a hand-held microphone
from days of yore . . . John Wayne had really classy
hand-held microphone technique in "Flying Tigers" back
in '42 and we all tried to follow in the Duke's footsteps
since. But a few years ago, the hand-held mic started
disappearing from the airplanes. I don't think the rentals
I fly even have them in the cockpit any more.
The concern was that for early intercom systems, mic
audio for the comm transmitter was handled through
active electronics in the audio system. Loss of the
audio system could cause one to lose the pilot's voice
audio path to any or all transmitters . . . maybe the
headphones too!
The prudent installer of such systems provided a "failsafe"
path from pilots headphones and mic to at least one comm
transceiver. This is illustrated on page 1.11 of
http://www.aeroelectric.com/Catalog/AEC/9009/9009-700E.pdf
where in the lower left corner of the wiring diagram, you
see "failsafe" jacks for microphone and headset wiring.
When things are not going well with the audio distribution
system, the pilot can unplug his headset from the normal
jacks and plug into failsafe jacks for completion
of the flight.
Modern intercoms provide a relay that will hard-wire
the pilots headset to a comm radio in the event of
power failure to the intercomm for whatever reason.
If your intercom has this feature, you're done. If not,
you can add failsafe jacks as illustrated so that
you can easily bypass the audio system as needed. With
two headsets in the airplane a need to carry
a "second microphone" for redundancy is covered.
Failsafe jacks cover the rest of the hazards
so the microphone mentioned in the Icom manual becomes
extra redundant and un-necessary.
Bob . . .
Message 20
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| Subject: | Re: HOT fuel guage |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 10:40 PM 7/24/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "Jack Eckdahl" <jeckdahl@sjrwmd.com>
>
>I have 30 hours on my RV9A. Today, after taking off, I noticed an
>electrical "smell". I glanced at all my guages and noticed moisture
>inside the lense of the Vans fuel gauge. It was working, but I had never
>noticed moisture before. My hanger is not humidity proof, but the plane
>has never been wet. I reached under the panel and noticed that the guage
>was extremely hot to the touch. I landed and did my best to look behind
>the panel. I saw no melted or burnt wires, but the guage was still very
>hot and moisture continued to be behind the faceplate. What should I do
>to troubleshoot? What would cause this after 30 hours of no known
>problem? thanks, Jack
Your fuel gage tenants probably had a grease fire
while frying up a batch of taco shells. Geesh! I cannot
imagine what kind of failure would produce the symptoms
you've cited. The only time I saw an instrument "fog" up
like that, it wasn't moisture but smoke. The "fog" was
still on the instrument face when I disassembled it
for failure analysis. See:
http://www.aeroelectric.com/Pictures/Letting_Smoke_Out_1.jpg
In this case, the instrument (expanded scale voltmeter)
had been subject to an OV condition. I can't imagine what
would have caused it. It would be interesting to do a
an autopsy on it to see if we can figure it out.
Bob . . .
Message 21
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| Subject: | Z13 and switches |
--> AeroElectric-List message posted by: <pgroell@chello.fr>
Hello Bob and readers,
I'm still in the very early planning stages of building a RV-7A, but as I'm stuck
do to workshop availability, and I try to plan ahead with systems, etc...
I really like the architecture of Z13 and have questions about the switches.
1) As I understand, the ESS BUS switch and AUX ALT FIELD switch are closed after
MAIN ALT failure and after the MASTER SWITCH is opened. Would it be of interest
to have the two functions (ESS BUS close and AUX ALT FIELD ON) combined in
one switch . First position would connect the ESS BUS, second position would
close the AUX ALT FIELD switch.
2) Both alternators' circuits are equipped with shunts to "read" their load, as
the AUX ALT will only be running in case of MAIN ALT failure, the load needs
only to be read in this case. To be able to use only one instrument would it make
sense to wire the circuit so that the instrument would read MAIN ALT load
when MAIN ALT is running and AUX ALT load when AUX ALT is brought on line (may
be with the AUX ALT FIELD switch). I know this may interfere with question 1
above.
Maybe these questions don't make any sense or I have been unable to find the answers.
I'm trying to find a way to have the smallest amount of switches to throw in case
of MAIN ALT failure.
Best regards
Pascal
Message 22
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| Subject: | Re: P/N, source for microphone? |
--> AeroElectric-List message posted by: "Bill Maxwell" <wrmaxwell@bigpond.com>
You're most welcome. Actually, although the A200 is a good radio, if now a
little dated in terms of memory capacity and some other modern features, it
has always been let down by a less than comprehensive manuals, including the
service manual.
Bill
----- Original Message -----
From: "John Swartout" <jgswartout@earthlink.net>
Subject: RE: AeroElectric-List: P/N, source for microphone?
> --> AeroElectric-List message posted by: "John Swartout"
> <jgswartout@earthlink.net>
>
> Yes, I mean "headsets." Thanks. Since there will be two headsets, it
> does seem unnecessarily redundant to add a mike to the panel.. Thanks
> for the tip.
>
> John
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bill
> Maxwell
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: P/N, source for microphone?
>
> --> AeroElectric-List message posted by: "Bill Maxwell"
> <wrmaxwell@bigpond.com>
>
> When you say "headphones" do you mean "headsets" John? If so, they of
> course incorporate a microphone and that is all the A200 needs to be
> able to
> transmit your voice, once the headset is correctly wired to the A200's
> phones and mic circuits. You certainly will not need, nor be able to
> use a
> second, presumably hand operated, microphone without also installing a
> switch or resorting to additional wiring.
>
> Bill
> --- Original Message -----
> From: "John Swartout" <jgswartout@earthlink.net>
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: P/N, source for microphone?
>
>
>> --> AeroElectric-List message posted by: "John Swartout"
>> <jgswartout@earthlink.net>
>>
>> My Icom A200 com radio needs a microphone. I will always be using
>> headphones, but the manual for the radio says I should also have a
>> microphone, either a low-impedance carbon mike or a dynamic mike,
> which
>> requires a pre-amp. Microphone impedance is 600 ohms. As this device
>> will primarily be unwanted clutter in the cockpit, I would like to get
>> the cheapest mike that will function if ever needed. Any suggestions?
>> Thank you all.
>>
>> John
>>
>>
>>
>
>
>
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