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bonanza(at)vodamail.co.za
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 Posted: Fri Nov 24, 2006 7:46 am Post subject: Auto-pilots |
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Hey listers,
I'm looking around at auto-pilots. Obviously searched the net a bit, but still wondering, any recommendations from the list?
Bob Verwey
A35 Bonanza ZU-DLW
[quote][b]
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khorton01(at)rogers.com
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| Posted: Fri Nov 24, 2006 10:26 am Post subject: Auto-pilots |
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On 24-Nov-06, at 10:44 AM, Bob Verwey wrote:
| Quote: | Hey listers,
I'm looking around at auto-pilots. Obviously searched the net a bit, but still wondering, any recommendations from the list?
Bob Verwey
A35 Bonanza ZU-DLW
|
Do you need an installation for a type-certificated aircraft, or amateur-built? What capabilities do you want? Wing leveler only? Heading select? Altitude hold? Airspeed hold? Vertical speed hold? Altitude preselect? Coupled ILS? Coupled GPS? Coupled approach VNAV?
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
[quote][b]
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bonanza(at)vodamail.co.za
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| Posted: Sat Nov 25, 2006 6:43 am Post subject: Auto-pilots |
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OBAM, Heading select & alt hold, coupled GPS would be nice!
Thanx
Bob Verwey
A35 Bonanza et al
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Kevin Horton
Sent: 24 Nov 2006 08:25 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: AeroElectric-List: Auto-pilots
On 24-Nov-06, at 10:44 AM, Bob Verwey wrote:
| Quote: | Hey listers,
I'm looking around at auto-pilots. Obviously searched the net a bit, but still wondering, any recommendations from the list?
Bob Verwey
A35 Bonanza ZU-DLW
|
Do you need an installation for a type-certificated aircraft, or amateur-built? What capabilities do you want? Wing leveler only? Heading select? Altitude hold? Airspeed hold? Vertical speed hold? Altitude preselect? Coupled ILS? Coupled GPS? Coupled approach VNAV?
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
[quote]
href="http://www.aeroelectric.com">www.aeroelectric.com
href="http://www.buildersbooks.com">www.buildersbooks.com
href="http://www.kitlog.com">www.kitlog.com
href="http://www.homebuilthelp.com">www.homebuilthelp.com
href="http://www.matronics.com/contribution">http://www.matronics.com/chref="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List
[b]
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Earl_Schroeder(at)juno.co
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| Posted: Sat Nov 25, 2006 7:41 am Post subject: Auto-pilots |
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I have the Pictorial Pilot and AlTrak so I vote for TruTrak! I would
have invested in the ADI Pilot if it was available when I purchased.
Both work great in my Lancair. Earl
Bob Verwey wrote:
| Quote: |
OBAM, Heading select & alt hold, coupled GPS would be nice!
Thanx
Bob Verwey
A35 Bonanza et al
------------------------------------------------------------------------
*From:* owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] *On Behalf Of
*Kevin Horton
*Sent:* 24 Nov 2006 08:25 PM
*To:* aeroelectric-list(at)matronics.com
*Subject:* Re: Auto-pilots
On 24-Nov-06, at 10:44 AM, Bob Verwey wrote:
> Hey listers,
> I'm looking around at auto-pilots. Obviously searched the net a bit,
> but still wondering, any recommendations from the list?
> Bob Verwey
> A35 Bonanza ZU-DLW
Do you need an installation for a type-certificated aircraft, or
amateur-built? What capabilities do you want? Wing leveler only?
Heading select? Altitude hold? Airspeed hold? Vertical speed hold?
Altitude preselect? Coupled ILS? Coupled GPS? Coupled approach VNAV?
Kevin Horton
RV-8 (Finishing Kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
*
href="http://www.aeroelectric.com">www.aeroelectric.com
href="http://www.buildersbooks.com">www.buildersbooks.com
href="http://www.kitlog.com">www.kitlog.com
href="http://www.homebuilthelp.com">www.homebuilthelp.com
href="http://www.matronics.com/contribution">http://www.matronics.com/chref="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List
*
*
*
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bicyclop(at)pacbell.net
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khorton01(at)rogers.com
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| Posted: Sat Nov 25, 2006 12:27 pm Post subject: Auto-pilots |
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There are many happy customers of both the TruTrak and Trio
autopilots. They both have alt hold and coupled lateral GPS. But,
neither one offers heading select. They both have track select,
using track from the GPS. This isn't the same as heading select, but
you could manually turn to the desired heading, then have the
autopilot hold the current track.
If you want heading select, I think you would need to purchase a Blue
Mountain EFIS system and their autopilot. Or maybe S-Tec + an
expensive heading gyro with a heading output.
Heading select requires a gyro system that outputs heading, which is
generally fairly expensive. Some of the newer low cost EFIS systems
have an AHRS with a magnetic field sensor to get heading, but I don't
think any of them output the same type of signal as a gyro with
heading output, so you can't use them in place of a mechanical gryo,
unless the autopilot was built around the AHRS, as with Blue Mountain.
Kevin Horton
On 25 Nov 2006, at 09:41, Bob Verwey wrote:
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ainut(at)hiwaay.net
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| Posted: Sat Nov 25, 2006 1:17 pm Post subject: Auto-pilots |
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If I can determine and find the right stepper motors, I plan to build my
own 
David M.
Bob Verwey wrote:
| Quote: | Hey listers,
I'm looking around at auto-pilots. Obviously searched the net a bit,
but still wondering, any recommendations from the list?
Bob Verwey
A35 Bonanza ZU-DLW
------------------------------------------------------------------------
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stein(at)steinair.com
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| Posted: Sat Nov 25, 2006 4:48 pm Post subject: Auto-pilots |
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Hi Kevin,
Almost right.....but...Even the lowest priced TruTrak has an internal
magentometer (along with a little gyro/accelerometer) that allows you to fly
the airplane in magentic heading mode and select the heading in 1 degree
increments, or you can steer to a new magnetic heading. Naturally you have
to calibrate the thing before doing that, but the TruTrak's have been this
way since day one. I'm not 100% sure about Trio's AP's (even though I sell
those too) but I don't have one of theirs installed in my plane....whereas
I've been flying behind the TruTrak stuff for awhile now.
All of the above can be accomplished with the GPS removed from the aircraft.
Then it won't follow a course, but the magenetic heading is the "backup" in
case the GPS signal gets inturrepted or doesn't work, etc... It's much nicer
to have the GPS hooked to either of them, put a flightplan or "direct 2" in
the GPS, hit the NAV button and let go!
Either way, you'll be happy!
Cheers,
Stein.
[quote]--
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khorton01(at)rogers.com
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| Posted: Sat Nov 25, 2006 6:06 pm Post subject: Auto-pilots |
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Stein,
I did look at the TruTrak web site before posting, and found no
mention of a heading select mode, but digging deeper now I see some
mention in the Quick Reference Guide for the DigiTrak. The info in
the Quick Reference Guide is a bit spartan though. If you want to
fly a particular heading (vice a track), how do you tell the
autopilot to turn to that heading? Can the heading mode be used if
the GPS is functional?
Kevin
On 25 Nov 2006, at 19:47, SteinAir, Inc. wrote:
[quote]
<stein(at)steinair.com>
Hi Kevin,
Almost right.....but...Even the lowest priced TruTrak has an internal
magentometer (along with a little gyro/accelerometer) that allows
you to fly
the airplane in magentic heading mode and select the heading in 1
degree
increments, or you can steer to a new magnetic heading. Naturally
you have
to calibrate the thing before doing that, but the TruTrak's have
been this
way since day one. I'm not 100% sure about Trio's AP's (even
though I sell
those too) but I don't have one of theirs installed in my
plane....whereas
I've been flying behind the TruTrak stuff for awhile now.
All of the above can be accomplished with the GPS removed from the
aircraft.
Then it won't follow a course, but the magenetic heading is the
"backup" in
case the GPS signal gets inturrepted or doesn't work, etc... It's
much nicer
to have the GPS hooked to either of them, put a flightplan or
"direct 2" in
the GPS, hit the NAV button and let go!
Either way, you'll be happy!
Cheers,
Stein.
> --
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stein(at)steinair.com
Guest
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| Posted: Sat Nov 25, 2006 6:59 pm Post subject: Auto-pilots |
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As usual you are wise beyone your years! It's only a very basic magnetic
heading...you have to 'point' the airplane to a specific heading of sorts,
and once engaged a click of the knob or turn of the wheel (on my pic/pilot)
moves you one degree. You can't tell it to go to a specific heading
without a known starting point....hopefully referenced to your compass or
something. It's mainly a backup thing in case everything else in your
airplane fails (or you're me and you forgot to plug in the GPS then the
batteries go dead)! To use it with the GPS functional and installed, you
need to remove the GPS data feed, either by shutting the GPS off or turning
of the NMEA data stream.
Hope that clears things up. Like I said....you were kind of right - I just
had to point out that one little bit. Of course it's not the most powerful
bit of functionality in the world, but then it's not meant to be. It's
supposed to cover your rear in the case of other things failing. Like I
said, I'm not 100% sure about the Trio, and really not sure about how the
BMA in reality actually provides that info (and if it even really does or
still uses some GPS input), but I do know more about the TTAP's.
Cheers,
Stein.
--
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George McNutt
Joined: 09 Jan 2006
Posts: 30
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| Posted: Sat Nov 25, 2006 8:13 pm Post subject: Auto-pilots |
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Kevin Horton wrote:
| Quote: | (snip)
Heading select requires a gyro system that outputs heading, which is
generally fairly expensive. Some of the newer low cost EFIS systems
have an AHRS with a magnetic field sensor to get heading, but I don't
think any of them output the same type of signal as a gyro with
heading output, so you can't use them in place of a mechanical gryo,
unless the autopilot was built around the AHRS, as with Blue Mountain.
Kevin Horton
|
Hi Kevin & Steine
I hope I am not wrong here but I have been told that the GRT Sport EFIS
that I am installing will output heading, VOR and GPS signals to the
Trutrak autopilot all in the same RS232 format as the normal GPS nav
output. Therefore I am expecting to have GPS nav mode, heading select or
VOR/ILS tracking from my Trutrak ADI 2 when it is in Nav mode . This
requires the $400 moving map option in the Sport. In my installation the
A/P will normally get all inputs from EFIS but is switchable directly to
the GPS output for nav if the EFIS fails.
George in Langley BC
7A GRT Sport & Trutrak ADI-2.
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khorton01(at)rogers.com
Guest
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| Posted: Sun Nov 26, 2006 3:54 pm Post subject: Auto-pilots |
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Stein,
Thanks for the additional info. I am pondering eventually replacing
my Navaid wing-leveler with a more capable two-axis autopilot, so
this info is useful.
Kevin
do not archive
On 25 Nov 2006, at 21:56, Stein Bruch wrote:
[quote]
<stein(at)steinair.com>
As usual you are wise beyone your years! It's only a very basic
magnetic
heading...you have to 'point' the airplane to a specific heading of
sorts,
and once engaged a click of the knob or turn of the wheel (on my
pic/pilot)
moves you one degree. You can't tell it to go to a specific heading
without a known starting point....hopefully referenced to your
compass or
something. It's mainly a backup thing in case everything else in your
airplane fails (or you're me and you forgot to plug in the GPS then
the
batteries go dead)! To use it with the GPS functional and
installed, you
need to remove the GPS data feed, either by shutting the GPS off or
turning
of the NMEA data stream.
Hope that clears things up. Like I said....you were kind of right -
I just
had to point out that one little bit. Of course it's not the most
powerful
bit of functionality in the world, but then it's not meant to be.
It's
supposed to cover your rear in the case of other things failing.
Like I
said, I'm not 100% sure about the Trio, and really not sure about
how the
BMA in reality actually provides that info (and if it even really
does or
still uses some GPS input), but I do know more about the TTAP's.
Cheers,
Stein.
--
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bonanza(at)vodamail.co.za
Guest
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| Posted: Fri Dec 01, 2006 8:20 am Post subject: Auto-pilots |
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I have always admired the <can-do-it-myself'ers> in the electronics arena
<grin>
--
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nuckollsr(at)cox.net
Guest
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| Posted: Fri Dec 01, 2006 8:51 am Post subject: Auto-pilots |
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At 06:18 PM 12/1/2006 +0200, you wrote:
[quote]
I have always admired the <can-do-it-myself'ers> in the electronics arena
<grin>
--
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William.P.Dube(at)noaa.go
Guest
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| Posted: Fri Dec 01, 2006 9:44 am Post subject: Auto-pilots |
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Be sure to test the load on the stick with the wires on the stepper
shorted together. This "plug braking" mode offers MUCH more resistance
to movement than does the motor with open leads. Since the driver
silicon is quite likely to fail shorted (or stuck "on",) you must be
able to move the stick with shorted motor leads.
Also, be sure that the output driver is protected from the very large
voltages that the stepper will generate when the stick (or control
surface) is jerked around quickly. You can also arc across the stepper
windings if the driver circuit doesn't have something to limit these
voltages.
Some sort of mechanical clutch or shear pin in the servo drive is a
prudent addition. A toothed rubber belt can be selected that will
break/slip if need be.
The basics can be simple, but the details can get quite complicated.
Bill Dube'
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ainut(at)hiwaay.net
Guest
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| Posted: Fri Dec 01, 2006 11:15 am Post subject: Auto-pilots |
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I thought a simple breaker in the power supply line would be enough.
Remove the power and a stepper should free-wheel. Are there other
failure modes even with power removed?
Thanks,
David M.
Bill Dube wrote:
| Quote: |
<William.P.Dube(at)noaa.gov>
Be sure to test the load on the stick with the wires on the stepper
shorted together. This "plug braking" mode offers MUCH more resistance
to movement than does the motor with open leads. Since the driver
silicon is quite likely to fail shorted (or stuck "on",) you must be
able to move the stick with shorted motor leads.
Also, be sure that the output driver is protected from the very large
voltages that the stepper will generate when the stick (or control
surface) is jerked around quickly. You can also arc across the stepper
windings if the driver circuit doesn't have something to limit these
voltages.
Some sort of mechanical clutch or shear pin in the servo drive is a
prudent addition. A toothed rubber belt can be selected that will
break/slip if need be.
The basics can be simple, but the details can get quite
complicated.
Bill Dube'
>
|
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William.P.Dube(at)noaa.go
Guest
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| Posted: Fri Dec 01, 2006 12:52 pm Post subject: Auto-pilots |
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Stepper may not freewheel with the power removed from the driver
circuit. If the silicon is shorted, the stepper will plug brake. If you
force the stepper to spin too fast, you can blow out the silicon with
over-voltage, and perhaps cause it to short. The back-feed of voltage
into the driver circuit (on or off) from the spinning stepper can cause
all sorts of problems. If you simply spin the stepper itself too fast,
you can possibly arc over, then short the windings, causing it to plug
brake.
Your auto-pilot system should be designed to be tolerant of all of
these fault scenarios.
Steppers don't really "freewheel", instead they "cog."
Bill Dube'
David M. wrote:
| Quote: |
I thought a simple breaker in the power supply line would be enough.
Remove the power and a stepper should free-wheel. Are there other
failure modes even with power removed?
Thanks,
David M.
Bill Dube wrote:
>
> <William.P.Dube(at)noaa.gov>
>
> Be sure to test the load on the stick with the wires on the stepper
> shorted together. This "plug braking" mode offers MUCH more
> resistance to movement than does the motor with open leads. Since the
> driver silicon is quite likely to fail shorted (or stuck "on",) you
> must be able to move the stick with shorted motor leads.
>
> Also, be sure that the output driver is protected from the very large
> voltages that the stepper will generate when the stick (or control
> surface) is jerked around quickly. You can also arc across the
> stepper windings if the driver circuit doesn't have something to
> limit these voltages.
>
> Some sort of mechanical clutch or shear pin in the servo drive is a
> prudent addition. A toothed rubber belt can be selected that will
> break/slip if need be.
>
> The basics can be simple, but the details can get quite
> complicated.
>
> Bill Dube'
>
>>
>
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mprather(at)spro.net
Guest
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| Posted: Fri Dec 01, 2006 1:27 pm Post subject: Auto-pilots |
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Seems I've read of autopilots having a clutch of sorts. I would think
that an electromechanical clutch could be included which would allow
decoupling of the stepper motor from the control bellcrank. The clutch
would failsafe in the decoupled configuration..
Regards,
Matt-
| Quote: |
<William.P.Dube(at)noaa.gov>
Stepper may not freewheel with the power removed from the driver
circuit. If the silicon is shorted, the stepper will plug brake. If you
force the stepper to spin too fast, you can blow out the silicon with
over-voltage, and perhaps cause it to short. The back-feed of voltage
into the driver circuit (on or off) from the spinning stepper can cause
all sorts of problems. If you simply spin the stepper itself too fast,
you can possibly arc over, then short the windings, causing it to plug
brake.
Your auto-pilot system should be designed to be tolerant of all of
these fault scenarios.
Steppers don't really "freewheel", instead they "cog."
Bill Dube'
David M. wrote:
>
>
> I thought a simple breaker in the power supply line would be enough.
> Remove the power and a stepper should free-wheel. Are there other
> failure modes even with power removed?
>
> Thanks,
> David M.
> Bill Dube wrote:
>
>>
>> <William.P.Dube(at)noaa.gov>
>>
>> Be sure to test the load on the stick with the wires on the stepper
>> shorted together. This "plug braking" mode offers MUCH more
>> resistance to movement than does the motor with open leads. Since the
>> driver silicon is quite likely to fail shorted (or stuck "on",) you
>> must be able to move the stick with shorted motor leads.
>>
>> Also, be sure that the output driver is protected from the very large
>> voltages that the stepper will generate when the stick (or control
>> surface) is jerked around quickly. You can also arc across the
>> stepper windings if the driver circuit doesn't have something to
>> limit these voltages.
>>
>> Some sort of mechanical clutch or shear pin in the servo drive is a
>> prudent addition. A toothed rubber belt can be selected that will
>> break/slip if need be.
>>
>> The basics can be simple, but the details can get quite
>> complicated.
>>
>> Bill Dube'
>>
>>>
>>
>>
>>
>>
>>
>>
>>
>
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nuckollsr(at)cox.net
Guest
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| Posted: Fri Dec 01, 2006 8:22 pm Post subject: Auto-pilots |
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At 10:36 AM 12/1/2006 -0700, you wrote:
| Quote: |
Be sure to test the load on the stick with the wires on the stepper
shorted together. This "plug braking" mode offers MUCH more resistance to
movement than does the motor with open leads. Since the driver silicon is
quite likely to fail shorted (or stuck "on",) you must be able to move the
stick with shorted motor leads.
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Brushless dc motors have permanent magnet rotors that
do have a substantial backdriving force with the windings
shorted . . . but except for a small "gogging" force,
the backdriving torque is velocity related. In other words,
the motor can't "lock up" the shaft with simple shorted
windings . . . it can only resist motion with resitance
going up as velocity increases.
A stepper (or at least all the motors I've worked with)
don't have PM rotors and generate no driving EMF or
velocity related backdriving resistance.
| Quote: | Also, be sure that the output driver is protected from the very large
voltages that the stepper will generate when the stick (or control
surface) is jerked around quickly. You can also arc across the stepper
windings if the driver circuit doesn't have something to limit these voltages.
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Again, no permanent magnets, no back emf.
| Quote: | Some sort of mechanical clutch or shear pin in the servo drive is a
prudent addition. A toothed rubber belt can be selected that will
break/slip if need be.
|
I size the pinion gear width and material to provide
the last-ditch, mechanical fuse. Usually at about
60 to 100 lb-in of back driving force.
| Quote: | The basics can be simple, but the details can get quite complicated.
|
That's the nice thing about steppers. Very low parts count.
Very low risks to manual operability whether energized or
de-energized and all without clutches and brakes.
Bob . . .
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nuckollsr(at)cox.net
Guest
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| Posted: Fri Dec 01, 2006 8:24 pm Post subject: Auto-pilots |
|
|
At 01:14 PM 12/1/2006 -0600, you wrote:
| Quote: |
I thought a simple breaker in the power supply line would be enough.
Remove the power and a stepper should free-wheel. Are there other failure
modes even with power removed?
Thanks,
David M.
|
No, steppers have very benign failure modes and none
are "runaway" events. You don't want to OVERSIZE the
motor because you're depending on the steppers INABILITY
to hold position while energized should the electronics
hang up.
In a de-energized state, steppers are very free wheeling.
Bob . . .
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