Today's Message Index:
----------------------
0. 04:52 AM - LOC (Matt Dralle)
1. 06:15 AM - Re: Recomended Alternator (Robert L. Nuckolls, III)
2. 06:18 AM - Re: Recomended Alternator (OldBob Siegfried)
3. 06:24 AM - Re: Antennaes and primer (Robert L. Nuckolls, III)
4. 06:32 AM - Re: Transistorture (Robert L. Nuckolls, III)
5. 07:07 AM - Re: TCAD IAS Switch (with link to sketch) (Robert L. Nuckolls, III)
6. 07:21 AM - Hall Effect/Ammeter/query (Len Loudis)
7. 07:55 AM - Re: Hall Effect/Ammeter/query (Robert L. Nuckolls, III)
8. 08:55 AM - Re: Re: TCAD IAS Switch (with link to sketch) ()
9. 09:16 AM - Re: Antennaes and primer (Bill Hibbing)
10. 09:18 AM - Vacuum Pad Limitations - Weight & Torque... (Greg Campbell)
11. 09:18 AM - Re: AeroElectric-List Digest: 16 Msgs - 11/14/06 (William Morgan)
12. 10:32 AM - Re: Vacuum Pad Limitations - Weight & Torque... (rtitsworth)
13. 11:35 AM - Re: Vacuum Pad Limitations - Weight & Torque... (Matt Prather)
14. 04:23 PM - Re: Recomended Alternator (gordon or marge)
15. 05:28 PM - Re: Temperature units puzzle (Barlow, Jim D)
16. 05:54 PM - Re: The Real US Metric History (DBerelsman@aol.com)
17. 06:39 PM - Re: Vacuum Pad Limitations - Weight & Torque... (Robert L. Nuckolls, III)
18. 07:03 PM - Re: Temperature units puzzle (Robert L. Nuckolls, III)
19. 07:32 PM - Re: Re: TCAD IAS Switch (with link to sketch) (Don Vs)
20. 07:46 PM - Re: Recomended Alternator (Michel Creek)
21. 07:59 PM - Re: GTX327 power switching (phd1993)
Message 0
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Each year at the end of the List Fund Raiser, I post a message acknowledging everyone
that so generously made a Contribution to support the Lists. Its sort
of my way of publicly thanking everyone that took a minute to show their
appreciation for the Lists.
Won't you take a moment and assure that your name is on that List of Contributors
(LOC)? As a number of members have pointed out over the years, the List seems
at least - if not a whole lot more - valuable as a
building/flying/recreating/entertainment tool as your typical magazine subscription!
Please take minute and assure that your name is on this year's LOC! Show others
that you appreciate the Lists. Making a Contribution to support the Lists is
fast and easy using your Credit card or Paypal on the Secure Web Site:
http://www.matronics.com/contribution
or by popping a personal check in the mail to:
Matt Dralle / Matronics
PO Box 347
Livermore CA 94551-0347
I would like to thank everyone that has so generously made a Contribution thus
far in this year's List Fund Raiser! Remember that its YOUR support that keeps
these Lists going and improving! Don't forget to include a little comment
about how the Lists have helped you!
Best regards,
Matt Dralle
Matronics Email List Administrator
Message 1
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| Subject: | Re: Recomended Alternator |
At 09:37 PM 11/14/2006 -0800, you wrote:
><mwcreek@frontiernet.net>
>
>
>I'm new to this list and building a Bearhawk with an O-540. I'm looking for
>a ER 40 amp alternator that is less expensive than B&C's. Can anyone
>recommend a good model ND or equivalent? Same goes for regulators.
To my knowledge, there are no modern production alternators
designed to run with external regulators . . . at least not
in the volume automotive markets.
You can modify your own alternator. There's probably several
guides out there on the 'net. One that I'm aware of can be
viewed at:
http://www.miramarcollege.net/programs/avim/faculty/north/alternator/
Regulators are cheap. The generic "ford" regulator cited in
the 'Connection is one to consider.
OV protection and LV warning are also good features to have.
Regulation, OV protection =AND= LV warning can be had in
one box from B&C in the form of the LR-3 . . . or you can
craft your own devices from data gleaned from my website
or elsewhere.
My best recommendation is that you install an out-of-the-box
IR alternator. By the time you're ready to fly, we'll probably
have the hardware to add to your installation that will offer
all the features cited above while offering any time, any
circumstances, ON-OFF control of the alternator without concerns
for damage to the alternator or ship's systems.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 2
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| Subject: | Re: Recomended Alternator |
Good Morning Michel,
Welcome to the list.
I hope you find what you need, but may I interject one
thought?
I am primarily a pilot, secondarily a grease monkey.
My electrical knowledge is way down on the competency
scale. Nevertheless, I would suggest that you be very
cautious when searching for electrical components
based on the price of acquisition.
If your need for electrical power is minimal such as
is true when flying daytime VFR in non challenging
environments, an electrical failure may be no problem
at all, but if your area of operation is in a more
challenging environment, buying high quality
components may be well worth the money.
Bill Bainbridge, the owner of B&C, is dedicated to
producing high quality equipment at a reasonable
price.
While there are undoubtedly cheaper components
available, I doubt if you will find very many products
of the same or grater quality at a lower price.
My only connection with B&C is that I am a very happy
customer!
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
--- Michel Creek <mwcreek@frontiernet.net> wrote:
> Creek" <mwcreek@frontiernet.net>
>
>
> I'm new to this list and building a Bearhawk with an
> O-540. I'm looking for
> a ER 40 amp alternator that is less expensive than
> B&C's. Can anyone
> recommend a good model ND or equivalent? Same goes
> for regulators.
>
> Thanks,
> Mike C.
>
>
>
> Click on
> about
> provided
> www.buildersbooks.com
> Admin.
>
> browse
> Subscriptions page,
> FAQ,
> http://www.matronics.com/Navigator?AeroElectric-List
>
>
>
>
>
Message 3
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| Subject: | Re: Antennaes and primer |
At 08:14 AM 11/14/2006 -0800, you wrote:
>
>I have all my antennas..com, nav, and 2 gps antennas under fiberglass.
>The GPS antennas are just forward of the wind screen, theNav antenna is in
>the belly and the com in the leading edge of the vert stabilizer.
>
>The only difference between my plane and the prototype is the primer and
>my control surfaces (elevator, rudder, ailerons, and flaps) are carbon
>fiber not fiberglass.
>
>The Prototype used PPG K36 with K201 hardener, I used Dupont Nason 421-19
>with 483-87 hardener.
>
>The MDSS lists aluminum, iron sulfate and carbon black in unknown
>quantities in the DuPont product. These are not listed in th MDSS for the
>PPG product.
>
>I find I transmit and recieve normally on frequencies below 125.00 but TX
>and RX is very weak above this. My Nav reception is exceedingly weak
>across the board and both GPSs take up to 10 minutyes to lock and then
>only see 4 sats.
>
>The com nav bench checks fine and when I recieved the BMA Efiss and tested
>them in the car they locked on in seconds.
>
>Can the stuff in the primer cause this? If so how large an area around the
>antennas do I need to sand.
Without hard data from experiments in the laboratory and/or
repeatable experiments in the field, I doubt that anyone can
give you more than WAGed advice. It's a given that ANYTHING
you place between your antenna and some signal of interest
has an effect. The question becomes to what degree and what
level of acceptability.
But unless someone here on the List has encountered and
massaged you particular combination of conditions before,
we're hard pressed to be of meaningful assistance. Sorry.
You're in position to offer us data from your own experiments
. . . and perhaps someone will come along later and repeat
to confirm/discount your findings.
Bob . . .
Message 4
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At 09:40 AM 11/13/2006 -0800, you wrote:
>
>The circuit is just a ground to tell my TCAD that it is on the ground. A
>pressure switch ( I can only find NO in the range I need) is in the pitot
>system. The switch closes at roughly 50 knots. I have access to both ends
>of the switch. The switch is a micro pneumatic logic 503. Maybe you know a
>supplier that would sell me one that is NC.The closing of the switch is
>supposed to open the ground on the TCAD. I can easily convert the no to nc
>by using a relay, but, I thought a transistor may also work?? Just making
>an attempt to learn more electric stuff. I hope that this explanation
>works.
If we knew more about the internal wiring of the TCAD system, perhaps
the solution could be as simple as the first sketch below.
1a352a.jpg
However, the second sketch is 99.9% certain to work. All the parts are
available from Radio Shack.
Bob . . .
Message 5
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| Subject: | Re: TCAD IAS Switch (with link to sketch) |
The circuit is just a ground to tell my TCAD that it is on the ground. A
pressure switch ( I can only find NO in the range I need) is in the pitot
system. The switch closes at roughly 50 knots. I have access to both ends
of the switch. The switch is a micro pneumatic logic 503. Maybe you know a
supplier that would sell me one that is NC.The closing of the switch is
supposed to open the ground on the TCAD. I can easily convert the no to nc
by using a relay, but, I thought a transistor may also work?? Just making
an attempt to learn more electric stuff. I hope that this explanation
works.
If we knew more about the internal wiring of the TCAD system, perhaps
the solution could be as simple as the first sketch below.
(I didn't get the attachment here . . . I've posted the sketch
at: http://www.aeroelectric.com/temp/TCAD_Switch.pdf
However, the second sketch is 99.9% certain to work. All the parts are
available from Radio Shack.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 6
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| Subject: | Hall Effect/Ammeter/query |
Folks,
As others have said, placement of devices to measure health of your electrical
system is like decisions on primers! So my goal, rightly or wrongly: One Hall
Effect feeding my ACS 2005 eng monitor on my main alt B-lead to read as loadmeter.
When I switch to my SD8 backup alt, all wired per Z13-8, I want to keep
it very simple and switch to a second sensor reading charge or discharge.
The ACS is monitoring volts, of course, and is wired through the endurance bus.
I After looking at archives, I still remain unclear as to my questions(s) here:
a) where to place this second sensor and which way constitutes "alternator"
and "battery" sides in that placement, and b) will it read properly whether
or not one has selected "Alternate Ebus Feed".
Thanks in advance,
Len
RV7A nearing completion
---------------------------------
Sponsored Link
Mortgage rates near 39yr lows. $420,000 Mortgage for $1,399/mo - Calculate new
house payment
Message 7
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| Subject: | Re: Hall Effect/Ammeter/query |
At 07:20 AM 11/15/2006 -0800, you wrote:
>Folks,
>As others have said, placement of devices to measure health of your
>electrical system is like decisions on primers! So my goal, rightly or
>wrongly: One Hall Effect feeding my ACS 2005 eng monitor on my main alt
>B-lead to read as loadmeter. When I switch to my SD8 backup alt, all wired
>per Z13-8, I want to keep it very simple and switch to a second sensor
>reading charge or discharge. The ACS is monitoring volts, of course, and
>is wired through the endurance bus. I After looking at archives, I still
>remain unclear as to my questions(s) here: a) where to place this second
>sensor and which way constitutes "alternator" and "battery" sides in that
>placement, and b) will it read properly whether or not one has selected
>"Alternate Ebus Feed".
Suggest you fit your system with a low voltage warning
light fed from the e-bus. Run BOTH alternator feed wires
through the same hall-effect sensor. The instrument will
read output from either or both alternators on one sensor.
If you're down to the SD-8, reduce loads on the e-bus until
the loadmeter is at 8A or less . . . or until the lv light
stops flashing.
No selector switches. Simple and consistent interpretation
of ammeter readings.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 8
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| Subject: | Re: TCAD IAS Switch (with link to sketch) |
Bob,
Thanks for the help. I now have one more question. I am looking at the second
sketch and the two resistoirs look to be in series with the second resistor going
to ground. The resistors appears to half the volltage going to the transistor
when the switch is open with the other half going directly to ground. With
the switch closed the voltage that would have gone into the transistor would
now go to ground ? with no voltage going into the transistor? If you have time
I would like to hear a little explanation of the actual workings of this circuit.
I am not doubting it will work, I just want to understand what and why
it does what it does. Thanks for all the help. Don
---- "Robert L. Nuckolls wrote:
>
>
> The circuit is just a ground to tell my TCAD that it is on the ground. A
> pressure switch ( I can only find NO in the range I need) is in the pitot
> system. The switch closes at roughly 50 knots. I have access to both ends
> of the switch. The switch is a micro pneumatic logic 503. Maybe you know a
> supplier that would sell me one that is NC.The closing of the switch is
> supposed to open the ground on the TCAD. I can easily convert the no to nc
> by using a relay, but, I thought a transistor may also work?? Just making
> an attempt to learn more electric stuff. I hope that this explanation
> works.
>
> If we knew more about the internal wiring of the TCAD system, perhaps
> the solution could be as simple as the first sketch below.
>
> (I didn't get the attachment here . . . I've posted the sketch
> at: http://www.aeroelectric.com/temp/TCAD_Switch.pdf
>
> However, the second sketch is 99.9% certain to work. All the parts are
> available from Radio Shack.
>
> Bob . . .
> ---------------------------------------------------------
> < What is so wonderful about scientific truth...is that >
> < the authority which determines whether there can be >
> < debate or not does not reside in some fraternity of >
> < scientists; nor is it divine. The authority rests >
> < with experiment. >
> < --Lawrence M. Krauss >
> ---------------------------------------------------------
>
>
>
>
>
Message 9
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| Subject: | Re: Antennaes and primer |
The primer may be your problem. I've got a Glasair Super 2 and I used PPG
K36 primer and PPG Concept paint and have had no problem. My GPS antenna is
located, like yours, ahead of the windscreen area inside of the airplane.
My comm antenna is located in the vertical stab.
Bill
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Sent: Wednesday, November 15, 2006 8:23 AM
Subject: Re: AeroElectric-List: Antennaes and primer
> <nuckollsr@cox.net>
>
> At 08:14 AM 11/14/2006 -0800, you wrote:
>
>>
>>I have all my antennas..com, nav, and 2 gps antennas under fiberglass.
>>The GPS antennas are just forward of the wind screen, theNav antenna is in
>>the belly and the com in the leading edge of the vert stabilizer.
>>
>>The only difference between my plane and the prototype is the primer and
>>my control surfaces (elevator, rudder, ailerons, and flaps) are carbon
>>fiber not fiberglass.
>>
>>The Prototype used PPG K36 with K201 hardener, I used Dupont Nason 421-19
>>with 483-87 hardener.
>>
>>The MDSS lists aluminum, iron sulfate and carbon black in unknown
>>quantities in the DuPont product. These are not listed in th MDSS for the
>>PPG product.
>>
>>I find I transmit and recieve normally on frequencies below 125.00 but TX
>>and RX is very weak above this. My Nav reception is exceedingly weak
>>across the board and both GPSs take up to 10 minutyes to lock and then
>>only see 4 sats.
>>
>>The com nav bench checks fine and when I recieved the BMA Efiss and tested
>>them in the car they locked on in seconds.
>>
>>Can the stuff in the primer cause this? If so how large an area around the
>>antennas do I need to sand.
>
>
> Without hard data from experiments in the laboratory and/or
> repeatable experiments in the field, I doubt that anyone can
> give you more than WAGed advice. It's a given that ANYTHING
> you place between your antenna and some signal of interest
> has an effect. The question becomes to what degree and what
> level of acceptability.
>
> But unless someone here on the List has encountered and
> massaged you particular combination of conditions before,
> we're hard pressed to be of meaningful assistance. Sorry.
>
> You're in position to offer us data from your own experiments
> . . . and perhaps someone will come along later and repeat
> to confirm/discount your findings.
>
> Bob . . .
>
>
>
Message 10
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| Subject: | Vacuum Pad Limitations - Weight & Torque... |
Does anyone know how much torque the www.BandC.biz SD-20
alternator places on the accessory pad drive? The reason I ask
is because I put one on my TCM IO-550N engine and want to be
sure it is within the limits prescribed by the engine manufacturer.
My engine is described by the "Type Certificate Data Sheet" (TCDS) E3SO.
(This applies to most of the Continental IO-550 engine models.)
For those who may not be aware, the TCDS is the "official" source
of limitations on any Type Certified device that the FAA has approved.
The FAA is the official repository of the most up-to-date approved TCDS
and also maintains the historical records as well. You can find them at
http://www.AirWeb.FAA.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf
Anyway... the E3SO (Revision 8) Type Certificate says that
my engine's "accessory drives" (aka: "vacuum pump pads")
can each be loaded to 100 inch pounds of torque on a continuous basis,
and up to 800 inch pounds of torque on a static basis. A little ***
note indicates that one drive can be loaded to 160 in.lbs if the other
drive is limited to 100 in.lbs, (or in my case, not used.)
It also states that the accessory drive gear ratio is 1.5:1
so if I'm cruising at 2333 RPM or higher, then the alternator
should be turning at 3500 RPM or higher and able to put out a full 20 amps.
(according to the info at www.BandC.biz for it's SD-20 alternator)
The TCDS also shows that the maximum "overhang moment" of each accessory
should not exceed 40 inch pounds. By checking the specs at
http://www.bandc.biz/SD20REVC.pdf
it appears that the SD-20 weighs about 5.72 lbs and the CG is 3.15"
from the flange, for an overhang moment of about 18 inch pounds.
So far, so good!
It would be nice to know if the SD-20 has a "shear shaft"
to limit the damage in the event of a locked rotor. If it sheared around
800 inch pounds of static torque, that would be great to protect the engine.
So... to my great relief (and no big surprise), the SD-20 doesn't appear to
present
any excessive burden to the accessory drive on my IO-550. Thousands of
these
things flying around, so I didn't expect that there would be a problem.
############## EXTRA CREDIT ################
The only significant "unknown" is what the "continuous" & "static" torque of
the
alternator is while fully loaded at my max-rpm's ?
I'll challenge the electrically gifted on this list to come up with a
reasonable estimate
of the torque required to produce 20 amps at 3500 to 4050 alternator rpm.
I can follow it through VxA = Watts, Watts -> HP, HP / Efficiency = Input
Shaft HP,
Input Shaft HP / rpm = Force or Torque or something - but I get stuck about
there.
Bottom line, I'd like to know Input Shaft torque on a continuous basis
over the range of operating RPM's. (Perhaps it's highest at lower RPM ?)
If it's less than 160 inch pounds, then we're good to hang at least one
SD-20 (on a TCM IO-550)
If it's less than 100 inch pounds, then you could conceivably hang two
SD-20's -
(although it would take tiny fingers & a small miracle to get them both
bolted on & torqued properly! ;-)
########################################
If anybody is considering hanging two of the SD-20's, or has a radically
different engine,
you might want to look up your TCDS to find the latest "approved"
limitations.
You might find out you have a higher or lower gear ratio, torque limit, or
max overhang moment.
Just some thoughts for those who are cautious or curious.
(But I'm expecting answers from the electrically gifted! ;-)
Greg
Message 11
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| Subject: | Re: AeroElectric-List Digest: 16 Msgs - 11/14/06 |
Robert Bosch (yes, the same as the German company Bosch)invented and
patented the spark plug as we know it today. He let anyone use the
patent without paying a royalty fee IF THE THREADS WERE METRIC!
Scott
At 01:55 AM 11/15/2006, you wrote:
>Time: 07:36:38 PM PST US
>From: Kelly McMullen <kellym@aviating.com>
>Subject: Re: AeroElectric-List: Temperature (metric) units puzzle
>
>
>So explain how virtually every American car post WWII used 14mm plugs,
>until they went to those tiny ones. Perhaps 14mm and 18mm just happen to
>be equal to an English thread size. Especially since they both require
>an English unit plug socket, either 13/16 or 7/8.
>DBe
--
No virus found in this outgoing message.
Message 12
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| Subject: | Vacuum Pad Limitations - Weight & Torque... |
I'm planning on using a similar setup (still building). Thanks for the
info.
I have no reason to use anything else besides the B&C SD-20. However, does
anyone know of any alternatives?
I was at GAMI in Oklahoma last spring and saw a demo of the Supplenator (30
amp version) see: http://www.gami.com/supplenator.html
However, the like GAMI's phantom PRISM ignition system it is not yet
available (perhaps never?)
Rick Titsworth
Cell: 313-506-5604
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Greg
Campbell
Sent: Wednesday, November 15, 2006 12:18 PM
Subject: AeroElectric-List: Vacuum Pad Limitations - Weight & Torque...
Does anyone know how much torque the www.BandC.biz SD-20
alternator places on the accessory pad drive? The reason I ask
is because I put one on my TCM IO-550N engine and want to be
sure it is within the limits prescribed by the engine manufacturer.
My engine is described by the "Type Certificate Data Sheet" (TCDS) E3SO.
(This applies to most of the Continental IO-550 engine models.)
For those who may not be aware, the TCDS is the "official" source
of limitations on any Type Certified device that the FAA has approved.
The FAA is the official repository of the most up-to-date approved TCDS
and also maintains the historical records as well. You can find them at
http://www.AirWeb.FAA.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf
Anyway... the E3SO (Revision 8) Type Certificate says that
my engine's "accessory drives" (aka: "vacuum pump pads")
can each be loaded to 100 inch pounds of torque on a continuous basis,
and up to 800 inch pounds of torque on a static basis. A little ***
note indicates that one drive can be loaded to 160 in.lbs if the other
drive is limited to 100 in.lbs, (or in my case, not used.)
It also states that the accessory drive gear ratio is 1.5:1
so if I'm cruising at 2333 RPM or higher, then the alternator
should be turning at 3500 RPM or higher and able to put out a full 20 amps.
(according to the info at www.BandC.biz for it's SD-20 alternator)
The TCDS also shows that the maximum "overhang moment" of each accessory
should not exceed 40 inch pounds. By checking the specs at
http://www.bandc.biz/SD20REVC.pdf
it appears that the SD-20 weighs about 5.72 lbs and the CG is 3.15"
from the flange, for an overhang moment of about 18 inch pounds.
So far, so good!
It would be nice to know if the SD-20 has a "shear shaft"
to limit the damage in the event of a locked rotor. If it sheared around
800 inch pounds of static torque, that would be great to protect the engine.
So... to my great relief (and no big surprise), the SD-20 doesn't appear to
present
any excessive burden to the accessory drive on my IO-550. Thousands of
these
things flying around, so I didn't expect that there would be a problem.
############## EXTRA CREDIT ################
The only significant "unknown" is what the "continuous" & "static" torque of
the
alternator is while fully loaded at my max-rpm's ?
I'll challenge the electrically gifted on this list to come up with a
reasonable estimate
of the torque required to produce 20 amps at 3500 to 4050 alternator rpm.
I can follow it through VxA = Watts, Watts -> HP, HP / Efficiency = Input
Shaft HP,
Input Shaft HP / rpm = Force or Torque or something - but I get stuck about
there.
Bottom line, I'd like to know Input Shaft torque on a continuous basis
over the range of operating RPM's. (Perhaps it's highest at lower RPM ?)
If it's less than 160 inch pounds, then we're good to hang at least one
SD-20 (on a TCM IO-550)
If it's less than 100 inch pounds, then you could conceivably hang two
SD-20's -
(although it would take tiny fingers & a small miracle to get them both
bolted on & torqued properly! ;-)
########################################
If anybody is considering hanging two of the SD-20's, or has a radically
different engine,
you might want to look up your TCDS to find the latest "approved"
limitations.
You might find out you have a higher or lower gear ratio, torque limit, or
max overhang moment.
Just some thoughts for those who are cautious or curious.
(But I'm expecting answers from the electrically gifted! ;-)
Greg
Message 13
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| Subject: | Re: Vacuum Pad Limitations - Weight & Torque... |
Hello Greg,
It looks to me that the only thing missing in your calculation is hp
torque (ft-lbs) x RPM / 5252 or torque = hp x 5252 / RPM.
Let's say the alternator is 50% efficient - a very conservative number, I
think.
SD-20 Output Watts = 20A * 13.5V (guess) = 270Watts
with 50% efficiency, that's 540Watts input.
That's 0.723hp (power = 540Watts/746Watts/1hp) - 1hp = 746Watts
Seems like worst case torque might happen when the alternator is at the
lowest RPM - and producing maximum current. The alternator is rated at
3500RPM.
Torque = 0.723hp x 5252 / 3500 = 1.1ft-lb = 13.03in-lb.
Assumptions to be checked:
- My math.
- Shaft load above 3500RPM doesn't significantly increase.
- Dynamic torque load is minimal - I have noticed that when turning PM
dynamos, there are small magnetic "bumps" to get over. I suspect that
the magnitude of these bumps is small, but I don't know.
- Overall dynamo efficiency.
Regards,
Matt-
> Does anyone know how much torque the www.BandC.biz SD-20
> alternator places on the accessory pad drive? The reason I ask
> is because I put one on my TCM IO-550N engine and want to be
> sure it is within the limits prescribed by the engine manufacturer.
>
> My engine is described by the "Type Certificate Data Sheet" (TCDS) E3SO.
> (This applies to most of the Continental IO-550 engine models.)
>
> For those who may not be aware, the TCDS is the "official" source
> of limitations on any Type Certified device that the FAA has approved.
> The FAA is the official repository of the most up-to-date approved TCDS
> and also maintains the historical records as well. You can find them at
> http://www.AirWeb.FAA.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf
>
> Anyway... the E3SO (Revision 8) Type Certificate says that
> my engine's "accessory drives" (aka: "vacuum pump pads")
> can each be loaded to 100 inch pounds of torque on a continuous basis,
> and up to 800 inch pounds of torque on a static basis. A little ***
> note indicates that one drive can be loaded to 160 in.lbs if the other
> drive is limited to 100 in.lbs, (or in my case, not used.)
>
> It also states that the accessory drive gear ratio is 1.5:1
> so if I'm cruising at 2333 RPM or higher, then the alternator
> should be turning at 3500 RPM or higher and able to put out a full 20
> amps.
> (according to the info at www.BandC.biz for it's SD-20 alternator)
>
> The TCDS also shows that the maximum "overhang moment" of each accessory
> should not exceed 40 inch pounds. By checking the specs at
> http://www.bandc.biz/SD20REVC.pdf
> it appears that the SD-20 weighs about 5.72 lbs and the CG is 3.15"
> from the flange, for an overhang moment of about 18 inch pounds.
> So far, so good!
>
> It would be nice to know if the SD-20 has a "shear shaft"
> to limit the damage in the event of a locked rotor. If it sheared around
> 800 inch pounds of static torque, that would be great to protect the
> engine.
>
>
> So... to my great relief (and no big surprise), the SD-20 doesn't appear
> to
> present
> any excessive burden to the accessory drive on my IO-550. Thousands of
> these
> things flying around, so I didn't expect that there would be a problem.
>
> ############## EXTRA CREDIT ################
> The only significant "unknown" is what the "continuous" & "static" torque
> of
> the
> alternator is while fully loaded at my max-rpm's ?
>
> I'll challenge the electrically gifted on this list to come up with a
> reasonable estimate
> of the torque required to produce 20 amps at 3500 to 4050 alternator rpm.
> I can follow it through VxA = Watts, Watts -> HP, HP / Efficiency = Input
> Shaft HP,
> Input Shaft HP / rpm = Force or Torque or something - but I get stuck
> about
> there.
>
> Bottom line, I'd like to know Input Shaft torque on a continuous basis
> over the range of operating RPM's. (Perhaps it's highest at lower RPM ?)
>
> If it's less than 160 inch pounds, then we're good to hang at least one
> SD-20 (on a TCM IO-550)
> If it's less than 100 inch pounds, then you could conceivably hang two
> SD-20's -
> (although it would take tiny fingers & a small miracle to get them both
> bolted on & torqued properly! ;-)
>
> ########################################
>
> If anybody is considering hanging two of the SD-20's, or has a radically
> different engine,
> you might want to look up your TCDS to find the latest "approved"
> limitations.
> You might find out you have a higher or lower gear ratio, torque limit, or
> max overhang moment.
>
> Just some thoughts for those who are cautious or curious.
> (But I'm expecting answers from the electrically gifted! ;-)
>
> Greg
>
Message 14
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| Subject: | Recomended Alternator |
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Wednesday, November 15, 2006 9:14 AM
Subject: Re: AeroElectric-List: Recomended Alternator
To my knowledge, there are no modern production alternators
designed to run with external regulators . . . at least not
in the volume automotive markets.
http://www.miramarcollege.net/programs/avim/faculty/north/alternator/
Regulators are cheap. The generic "ford" regulator cited in
the 'Connection is one to consider.
OV protection and LV warning are also good features to have.
Regulation, OV protection =AND= LV warning can be had in
one box from B&C in the form of the LR-3 . . . or you can
craft your own devices from data gleaned from my website
or elsewhere.
My best recommendation is that you install an out-of-the-box
IR alternator. By the time you're ready to fly, we'll probably
have the hardware to add to your installation that will offer
all the features cited above while offering any time, any
circumstances, ON-OFF control of the alternator without concerns
for damage to the alternator or ship's systems.
Bob . . .
Bob: FYI and FWIW, a Ford engineer told me recently that certain Ford IR
alternators have a field control lead that connects to the ECM which, under
some circumstances, tells the alternator to shut down for various reasons,
such as under heavy acceleration. Additionally, to help deal with belt
noise on cold startups, the regulator can be directed to perform a "soft"
start. He acknowleged the need for OV protection and made me think it is
part of the regulator but was not specific and I didn't press the issue.
What it could mean for our business I have'nt much of a clue.
Gordon Comfort
N363GC
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 15
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| Subject: | Temperature units puzzle |
This article explains the lack of conversion.
http://capitalastronomers.org/ReganMeasurements.html
do not archive
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Gilles Thesee
Sent: Monday, November 13, 2006 3:27 PM
Subject: AeroElectric-List: Temperature units puzzle
<Gilles.Thesee@ac-grenoble.fr>
Hi Bob and all,
As a European I'm accustomed to see US citizens use Fahrenheit for CHT,
oil temp etc.
But in an original P51 manual, I'm puzzled to find temps in Celsius.
How come the Celsius were fashionable in the '40s when only Anglo-Saxons
were flying US airplanes, and now they have reverted to Fahrenheit ?
Thanks,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
Message 16
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| Subject: | Re: The Real US Metric History |
Get the real information here.
_http://ts.nist.gov/WeightsAndMeasures/Metric/upload/1136a.pdf_
(http://ts.nist.gov/WeightsAndMeasures/Metric/upload/1136a.pdf)
As explained to me by a historian at the US Metric Board:
"The US has technically been metric since 1992, because the US Govt (the
largest purchaser in the world) went metric in 1992. But after that earlier
fiasco - we just chose not to advertise it."
(http://ts.nist.gov/WeightsAndMeasures/Metric/upload/1136a.pdf)
Message 17
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| Subject: | Re: Vacuum Pad Limitations - Weight & Torque... |
At 12:17 PM 11/15/2006 -0500, you wrote:
>Does anyone know how much torque the <http://www.BandC.biz>www.BandC.biz SD-20
>alternator places on the accessory pad drive? The reason I ask
>is because I put one on my TCM IO-550N engine and want to be
>sure it is within the limits prescribed by the engine manufacturer.
A 20A, 14V alternator puts out 280 watts or 280/745 = .38 HP.
The alternator is never running at its design speed for
peak efficiency (about 5,000 rpm) so just for grins, let's
assume 50% (ugh) efficiency. This says mechanical demands on
the engine are 0.76 hp.
The horsepower is 33,000 ft-lbs of work per minute. Since the
baseline torque limit you've cited is in in-lb, we'll assume
a shaft of 1" radius sticking out the back of your engine. Spinning
that shaft at 3,500 rpm give us a surface speed on the shaft
of 3,500 x 1 x 2 x pi = 21,980 inches per minute or 21,980/12
1,831 feet/minute. Loading this shaft to 100 in-lb yields
100 x 1,831 = 183,100 ft-lb per minute or available
HP = 183,100/33,000 = 5.5
>
>My engine is described by the "Type Certificate Data Sheet" (TCDS) E3SO.
>(This applies to most of the Continental IO-550 engine models.)
>
>For those who may not be aware, the TCDS is the "official" source
>of limitations on any Type Certified device that the FAA has approved.
>The FAA is the official repository of the most up-to-date approved TCDS
>and also maintains the historical records as well. You can find them at
><http://www.AirWeb.FAA.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf>http://www.AirWeb.FAA.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf
>
>Anyway... the E3SO (Revision 8) Type Certificate says that
>my engine's "accessory drives" (aka: "vacuum pump pads")
>can each be loaded to 100 inch pounds of torque on a continuous basis,
>and up to 800 inch pounds of torque on a static basis. A little ***
>note indicates that one drive can be loaded to 160 in.lbs if the other
>drive is limited to 100 in.lbs, (or in my case, not used.)
>
>It also states that the accessory drive gear ratio is 1.5:1
>so if I'm cruising at 2333 RPM or higher, then the alternator
>should be turning at 3500 RPM or higher and able to put out a full 20 amps.
>(according to the info at <http://www.BandC.biz>www.BandC.biz for it's
>SD-20 alternator)
>
>The TCDS also shows that the maximum "overhang moment" of each accessory
>should not exceed 40 inch pounds. By checking the specs at
><http://www.bandc.biz/SD20REVC.pdf>http://www.bandc.biz/SD20REVC.pdf
>it appears that the SD-20 weighs about 5.72 lbs and the CG is 3.15"
>from the flange, for an overhang moment of about 18 inch pounds.
>So far, so good!
>
>It would be nice to know if the SD-20 has a "shear shaft"
>to limit the damage in the event of a locked rotor. If it sheared around
>800 inch pounds of static torque, that would be great to protect the engine.
It could not have been certified without one, and even
then B&C would not have produced one without a shear section
even if it were allowed.
>
>
>So... to my great relief (and no big surprise), the SD-20 doesn't appear
>to present
>any excessive burden to the accessory drive on my IO-550. Thousands of these
>things flying around, so I didn't expect that there would be a problem.
>
>############## EXTRA CREDIT ################
>The only significant "unknown" is what the "continuous" & "static" torque
>of the
>alternator is while fully loaded at my max-rpm's ?
>
>I'll challenge the electrically gifted on this list to come up with a
>reasonable estimate
>of the torque required to produce 20 amps at 3500 to 4050 alternator rpm.
>I can follow it through VxA = Watts, Watts -> HP, HP / Efficiency = Input
>Shaft HP,
>Input Shaft HP / rpm = Force or Torque or something - but I get stuck
>about there.
>
>Bottom line, I'd like to know Input Shaft torque on a continuous basis
>over the range of operating RPM's. (Perhaps it's highest at lower RPM ?)
If the power output is constant, then torque would go UP as
RPM goes down. However, this alternator is never operated at
minimum speed for full output so if you're loading the alternator
at max output for 3,500 RPM and then reduce RPM, then power
input (torque) will go down along with the output.
>
>If it's less than 160 inch pounds, then we're good to hang at least one
>SD-20 (on a TCM IO-550)
>If it's less than 100 inch pounds, then you could conceivably hang two
>SD-20's -
>(although it would take tiny fingers & a small miracle to get them both
>bolted on & torqued properly! ;-)
>
>########################################
>
>If anybody is considering hanging two of the SD-20's, or has a radically
>different engine,
>you might want to look up your TCDS to find the latest "approved"
>limitations.
>You might find out you have a higher or lower gear ratio, torque limit, or
>max overhang moment.
>
Correct. As we've observed, the SD-20 doesn't begin to load
the pad to limits so the engine is not mechanically
challenged if one COULD install two alternators.
Bob . . .
Message 18
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| Subject: | Temperature units puzzle |
At 05:27 PM 11/15/2006 -0800, you wrote:
><jim.d.barlow@intel.com>
>
>This article explains the lack of conversion.
>
>http://capitalastronomers.org/ReganMeasurements.html
This article assumes an often committed fundamental
flaw in logic made by some observers of government.
Namely that the president (or any other official) has
the power to effect much of anything - especially
something so interwoven into the fabric of an economy.
The article assumes: (1) that president A decrees that
"it shall be so". All dutiful citizens immediately
begin marching off toward that goal and (2) that
president B - [for what ever motivations] decreed that
"it shall not be so" and all progress toward that goal
ceased.
The argument then stacks a lot of confusing if
not irrelevant references around the assertion
thus laying the groundwork for a huge disconnect
between perceptions of some citizens and simple
realities - like market forces and economics in
a free society.
If president A's decree were to achieve fruition,
it would have required the full force of of every
agent of government with guns to confiscate and destroy
every article not designed, manufactured and maintained
in the metric system. This would have required laws
with severe penalties for not adhering to the "new
order". The process would have taken years and
the court system would have been swamped. The economic
impact to the country would have been incalculable.
Fortunately, both the force and will of our elected decision
makers have yet to rise to the necessary proportions.
Bottom line is if somebody mass markets a new
product with fasteners totally foreign to all popular
measurement systems but with performance value
and market appeal, the same manufacturer would make
a lot of money selling a set of tools to go along
with the product.
Bob . . .
Message 19
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| Subject: | Re: TCAD IAS Switch (with link to sketch) |
Bob,
Thanks for the information. I sent a previous response that I do not think
made it. In that one I asked about how and why the resistive portion of the
circuit was there. I figured it out and think that I actuaslly learned
something today. Thanks again.
Don
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
L. Nuckolls, III
Sent: Wednesday, November 15, 2006 7:06 AM
Subject: AeroElectric-List: Re: TCAD IAS Switch (with link to sketch)
<nuckollsr@cox.net>
The circuit is just a ground to tell my TCAD that it is on the ground. A
pressure switch ( I can only find NO in the range I need) is in the pitot
system. The switch closes at roughly 50 knots. I have access to both ends
of the switch. The switch is a micro pneumatic logic 503. Maybe you know a
supplier that would sell me one that is NC.The closing of the switch is
supposed to open the ground on the TCAD. I can easily convert the no to nc
by using a relay, but, I thought a transistor may also work?? Just making
an attempt to learn more electric stuff. I hope that this explanation
works.
If we knew more about the internal wiring of the TCAD system, perhaps
the solution could be as simple as the first sketch below.
(I didn't get the attachment here . . . I've posted the sketch
at: http://www.aeroelectric.com/temp/TCAD_Switch.pdf
However, the second sketch is 99.9% certain to work. All the parts are
available from Radio Shack.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 20
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| Subject: | Recomended Alternator |
Bob and Bob,
Thanks for the input and recommendations. I do like the B&C products as
they look to be top of the line quality, I'm just not sure I need to spend
that much for the type of flying I do. I'm mostly day VFR with some
occasional clear night flying for no more than about 1 hour before dawn or
after dusk.
I'm also planning on installing a Dynon EFIS with a back-up battery.
Mike C.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Wednesday, November 15, 2006 6:14 AM
Subject: Re: AeroElectric-List: Recomended Alternator
<nuckollsr@cox.net>
At 09:37 PM 11/14/2006 -0800, you wrote:
><mwcreek@frontiernet.net>
>
>
>I'm new to this list and building a Bearhawk with an O-540. I'm looking
for
>a ER 40 amp alternator that is less expensive than B&C's. Can anyone
>recommend a good model ND or equivalent? Same goes for regulators.
To my knowledge, there are no modern production alternators
designed to run with external regulators . . . at least not
in the volume automotive markets.
You can modify your own alternator. There's probably several
guides out there on the 'net. One that I'm aware of can be
viewed at:
http://www.miramarcollege.net/programs/avim/faculty/north/alternator/
Regulators are cheap. The generic "ford" regulator cited in
the 'Connection is one to consider.
OV protection and LV warning are also good features to have.
Regulation, OV protection =AND= LV warning can be had in
one box from B&C in the form of the LR-3 . . . or you can
craft your own devices from data gleaned from my website
or elsewhere.
My best recommendation is that you install an out-of-the-box
IR alternator. By the time you're ready to fly, we'll probably
have the hardware to add to your installation that will offer
all the features cited above while offering any time, any
circumstances, ON-OFF control of the alternator without concerns
for damage to the alternator or ship's systems.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 21
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|
| Subject: | Re: GTX327 power switching |
I have been bench/panel testing my GTX327 during cable assembly prior to final
installation in my panel and I can confirm the Pin 1 / Pin 15 configurations.
Now my question - if I have power supplied via Pin 15 and ground on Pin 25 WITHOUT
connecting either the transponder antenna or the altitude encoder what should
the GTX327 display at power on? How about power on while holding down the
FUNC button. All I am getting is the "backpanel" illuminated with no other display
items. Is this proper? Or do I need to connect either the antenna, the
altitude encoder, or both before I start seeing any items displayed on the panel?
Feedback appreciated.
Thanks,
Sam H.
Zenith 701 kit
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=74927#74927
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