OT - DC-10 gyros
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of
course, I had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that was stripped for parts around 2000. The gyro included the pull tag
with tail number, the license number of the A&P mechanic that pulled it,
and some other cool stuff.
What it turned out to really be is two gyros with two sets of
electronics in one box about 6" x 2" x 5" box, all vintage '80s or so.
Even better, it's a strapdown system. The actual gyro wheel is about the
size of your thumbnail. I've just started tracing things out, and I've
gotten the gyros to spin up. I really love mechanical gyros for some
reason, too bad there's not a gyro-nuts group. I'm going to have great
fun getting the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for
the gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power?
I faked it with a signal generator and power amp, but that's a bit
bulky. I'm thinking I'll use one of the class-D amp ICs and a simple
op-amp phase-shift sine generator.
Topical in a more abstract way, strapdown systems really are very
interesting. They require precise integration of the rate output over
time to derive velocity and position, and really weren't practical until
the 70's when small enough computers existed to do the requisite
calculations. (I worked on the nav system for the Trident missile back
in my Draper Labs days).
--
Bill Ezell
They said 'Windows or better'
so I used Linux.
How about one of those 2kw car stereo amps with a 555 input tone ?
--- On Wed, 3/27/13, Bill Ezell wje@quackers.net wrote:
From: Bill Ezell wje@quackers.net
Subject: [time-nuts] OT - DC-10 gyros
To: time-nuts@febo.com
Date: Wednesday, March 27, 2013, 1:40 PM
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course, I had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10 that was stripped for parts around 2000. The gyro included the pull tag with tail number, the license number of the A&P mechanic that pulled it, and some other cool stuff.
What it turned out to really be is two gyros with two sets of electronics in one box about 6" x 2" x 5" box, all vintage '80s or so. Even better, it's a strapdown system. The actual gyro wheel is about the size of your thumbnail. I've just started tracing things out, and I've gotten the gyros to spin up. I really love mechanical gyros for some reason, too bad there's not a gyro-nuts group. I'm going to have great fun getting the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for the gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power? I faked it with a signal generator and power amp, but that's a bit bulky. I'm thinking I'll use one of the class-D amp ICs and a simple op-amp phase-shift sine generator.
Topical in a more abstract way, strapdown systems really are very interesting. They require precise integration of the rate output over time to derive velocity and position, and really weren't practical until the 70's when small enough computers existed to do the requisite calculations. (I worked on the nav system for the Trident missile back in my Draper Labs days).
-- Bill Ezell
They said 'Windows or better'
so I used Linux.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Watch eBay for a small static inverter. I got an Abbott one for under $50.
It takes 28 VDC and puts out 115VAC 400 Hz.
-John
===================
How about one of those 2kw car stereo amps with a 555 input tone ?
--- On Wed, 3/27/13, Bill Ezell wje@quackers.net wrote:
From: Bill Ezell wje@quackers.net
Subject: [time-nuts] OT - DC-10 gyros
To: time-nuts@febo.com
Date: Wednesday, March 27, 2013, 1:40 PM
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course,
I had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that was stripped for parts around 2000. The gyro included the pull tag
with tail number, the license number of the A&P mechanic that pulled it,
and some other cool stuff.
What it turned out to really be is two gyros with two sets of electronics
in one box about 6" x 2" x 5" box, all vintage '80s or so. Even better,
it's a strapdown system. The actual gyro wheel is about the size of your
thumbnail. I've just started tracing things out, and I've gotten the gyros
to spin up. I really love mechanical gyros for some reason, too bad
there's not a gyro-nuts group. I'm going to have great fun getting the
package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for
the gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power? I
faked it with a signal generator and power amp, but that's a bit bulky.
I'm thinking I'll use one of the class-D amp ICs and a simple op-amp
phase-shift sine generator.
Topical in a more abstract way, strapdown systems really are very
interesting. They require precise integration of the rate output over time
to derive velocity and position, and really weren't practical until the
70's when small enough computers existed to do the requisite
calculations. (I worked on the nav system for the Trident missile back in
my Draper Labs days).
-- Bill Ezell
They said 'Windows or better'
so I used Linux.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
For "thumbsized" gyros, the power-drain is probably very slight.
A class-D may or may not be a good idea, I'd worry about the
stability faced with a "weird" load like motors.
That said, I have been toturing one of these to no end, and
not managed to kill it yet:
http://classdaudio.com/amplifier-modules/ti-300-amplifier.html
Depending on the actual power-requirement, you can also consider
the NatSemi audio chips, for instance the LM3875 "gainclone".
It is basically a very good high-power op-amp.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi
The first question is "how much 400 Hz power do I need?". Without knowing if it's tens of amps (no, it's not…) or a tenth of an amp, it's a bit though to decide how much to spend on the solution.
Eight ohms at 28 volts would be just a bit under 4 amps. It's also right at 100 watts. I'd be very surprised it you need anywhere near that much current. You probably want a pure sine wave to keep everything happy. A lot of the simple inverters are "sort of" sine waves. I think I'd vote for something like an cheap audio amp driven by a nice clean / stable 400 Hz tone.
Bob
On Mar 27, 2013, at 4:40 PM, Bill Ezell wje@quackers.net wrote:
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course, I had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10 that was stripped for parts around 2000. The gyro included the pull tag with tail number, the license number of the A&P mechanic that pulled it, and some other cool stuff.
What it turned out to really be is two gyros with two sets of electronics in one box about 6" x 2" x 5" box, all vintage '80s or so. Even better, it's a strapdown system. The actual gyro wheel is about the size of your thumbnail. I've just started tracing things out, and I've gotten the gyros to spin up. I really love mechanical gyros for some reason, too bad there's not a gyro-nuts group. I'm going to have great fun getting the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for the gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power? I faked it with a signal generator and power amp, but that's a bit bulky. I'm thinking I'll use one of the class-D amp ICs and a simple op-amp phase-shift sine generator.
Topical in a more abstract way, strapdown systems really are very interesting. They require precise integration of the rate output over time to derive velocity and position, and really weren't practical until the 70's when small enough computers existed to do the requisite calculations. (I worked on the nav system for the Trident missile back in my Draper Labs days).
--
Bill Ezell
They said 'Windows or better'
so I used Linux.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Good points, Bob. At 400 Hz and low power, I'd think a decent LC low-pass
filter would be feasible for cleaning up any trash on the inverter output.
LC to minimize the series losses and provide a bit of peaking at 400 Hz.
Tom Holmes, N8ZM
Tipp City, OH
EM79
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Bob Camp
Sent: Wednesday, March 27, 2013 6:21 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] OT - DC-10 gyros
Hi
The first question is "how much 400 Hz power do I need?". Without knowing
if it's
tens of amps (no, it's not.) or a tenth of an amp, it's a bit though to
decide how
much to spend on the solution.
Eight ohms at 28 volts would be just a bit under 4 amps. It's also right
at 100
watts. I'd be very surprised it you need anywhere near that much current.
You
probably want a pure sine wave to keep everything happy. A lot of the
simple
inverters are "sort of" sine waves. I think I'd vote for something like an
cheap
audio amp driven by a nice clean / stable 400 Hz tone.
Bob
On Mar 27, 2013, at 4:40 PM, Bill Ezell wje@quackers.net wrote:
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of
course, I had
to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that
was stripped for parts around 2000. The gyro included the pull tag with
tail
number, the license number of the A&P mechanic that pulled it, and some
other
cool stuff.
What it turned out to really be is two gyros with two sets of
electronics in one
box about 6" x 2" x 5" box, all vintage '80s or so. Even better, it's a
strapdown
system. The actual gyro wheel is about the size of your thumbnail. I've
just started
tracing things out, and I've gotten the gyros to spin up. I really love
mechanical
gyros for some reason, too bad there's not a gyro-nuts group. I'm going to
have
great fun getting the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for
the
gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power?
I
faked it with a signal generator and power amp, but that's a bit bulky.
I'm thinking
I'll use one of the class-D amp ICs and a simple op-amp phase-shift sine
generator.
Topical in a more abstract way, strapdown systems really are very
interesting.
They require precise integration of the rate output over time to derive
velocity and
position, and really weren't practical until the 70's when small enough
computers
existed to do the requisite calculations. (I worked on the nav system for
the
Trident missile back in my Draper Labs days).
--
Bill Ezell
They said 'Windows or better'
so I used Linux.
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
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and follow the instructions there.
Great to know there's someone around who loves complex electro-mechanical
systems! I thought the population had dropped to zero!
Regards,
Lee
----- Original Message -----
From: "Bill Ezell" wje@quackers.net
To: time-nuts@febo.com
Sent: Wednesday, March 27, 2013 2:40 PM
Subject: [time-nuts] OT - DC-10 gyros
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course,
I had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that was stripped for parts around 2000. The gyro included the pull tag
with tail number, the license number of the A&P mechanic that pulled it,
and some other cool stuff.
What it turned out to really be is two gyros with two sets of electronics
in one box about 6" x 2" x 5" box, all vintage '80s or so. Even better,
it's a strapdown system. The actual gyro wheel is about the size of your
thumbnail. I've just started tracing things out, and I've gotten the gyros
to spin up. I really love mechanical gyros for some reason, too bad
there's not a gyro-nuts group. I'm going to have great fun getting the
package traced out and running.
Yeah I'd join a gyro-nuts group. I have a shelf full of weird gyros, a stable
platform, other gyro stuff. I made a little power supply to make 28 volts 3
phase 400 Hz, found it in an app note, for running a set of three tiny rate
gyros I picked up. I'll go dig it out and let you know.
Peter
On 3/27/2013 4:40 PM, Bill Ezell wrote:
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course, I
had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10 that
was stripped for parts around 2000. The gyro included the pull tag with tail
number, the license number of the A&P mechanic that pulled it, and some other
cool stuff.
What it turned out to really be is two gyros with two sets of electronics in
one box about 6" x 2" x 5" box, all vintage '80s or so. Even better, it's a
strapdown system. The actual gyro wheel is about the size of your thumbnail.
I've just started tracing things out, and I've gotten the gyros to spin up. I
really love mechanical gyros for some reason, too bad there's not a gyro-nuts
group. I'm going to have great fun getting the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for the
gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power? I
faked it with a signal generator and power amp, but that's a bit bulky. I'm
thinking I'll use one of the class-D amp ICs and a simple op-amp phase-shift
sine generator.
Topical in a more abstract way, strapdown systems really are very interesting.
They require precise integration of the rate output over time to derive
velocity and position, and really weren't practical until the 70's when small
enough computers existed to do the requisite calculations. (I worked on the
nav system for the Trident missile back in my Draper Labs days).
An appropriate (but small) Group already exists:
http://tech.groups.yahoo.com/group/Aerospace_Hardware_Collectors_Group/
-John
=======================
Yeah I'd join a gyro-nuts group. I have a shelf full of weird gyros, a
stable
platform, other gyro stuff. I made a little power supply to make 28 volts
3
phase 400 Hz, found it in an app note, for running a set of three tiny
rate
gyros I picked up. I'll go dig it out and let you know.
Peter
On 3/27/2013 4:40 PM, Bill Ezell wrote:
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of
course, I
had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that
was stripped for parts around 2000. The gyro included the pull tag with
tail
number, the license number of the A&P mechanic that pulled it, and some
other
cool stuff.
What it turned out to really be is two gyros with two sets of
electronics in
one box about 6" x 2" x 5" box, all vintage '80s or so. Even better,
it's a
strapdown system. The actual gyro wheel is about the size of your
thumbnail.
I've just started tracing things out, and I've gotten the gyros to spin
up. I
really love mechanical gyros for some reason, too bad there's not a
gyro-nuts
group. I'm going to have great fun getting the package traced out and
running.
So, to be a bit more topical, the package of course needs 28V 400Hz for
the
gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power?
I
faked it with a signal generator and power amp, but that's a bit bulky.
I'm
thinking I'll use one of the class-D amp ICs and a simple op-amp
phase-shift
sine generator.
Topical in a more abstract way, strapdown systems really are very
interesting.
They require precise integration of the rate output over time to derive
velocity and position, and really weren't practical until the 70's when
small
enough computers existed to do the requisite calculations. (I worked on
the
nav system for the Trident missile back in my Draper Labs days).
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Is this part of an HSI (horizontal situation indicator), ADI (attitude
director indicator), INS (inertial navigation system), or autopilot? Are
the bearings dust?
Sounds like fun to play with though. What do you plan to do with it?
Joe
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Bill Ezell
Sent: Wednesday, March 27, 2013 3:40 PM
To: time-nuts@febo.com
Subject: [time-nuts] OT - DC-10 gyros
Well, I can come up with something topical, read on. :)
I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course, I
had to buy it.
What I got was the yaw-rate gyro package from a Northwest Airlines DC-10
that was stripped for parts around 2000. The gyro included the pull tag with
tail number, the license number of the A&P mechanic that pulled it, and some
other cool stuff.
What it turned out to really be is two gyros with two sets of electronics in
one box about 6" x 2" x 5" box, all vintage '80s or so.
Even better, it's a strapdown system. The actual gyro wheel is about the
size of your thumbnail. I've just started tracing things out, and I've
gotten the gyros to spin up. I really love mechanical gyros for some reason,
too bad there's not a gyro-nuts group. I'm going to have great fun getting
the package traced out and running.
So, to be a bit more topical, the package of course needs 28V 400Hz for the
gyros, 28VDC for something, and +/-15V for most of the electronics.
Question - anyone figured out some clever solution for the 400Hz power?
I faked it with a signal generator and power amp, but that's a bit bulky.
I'm thinking I'll use one of the class-D amp ICs and a simple op-amp
phase-shift sine generator.
Topical in a more abstract way, strapdown systems really are very
interesting. They require precise integration of the rate output over time
to derive velocity and position, and really weren't practical until the 70's
when small enough computers existed to do the requisite calculations. (I
worked on the nav system for the Trident missile back in my Draper Labs
days).
--
Bill Ezell
They said 'Windows or better'
so I used Linux.
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
On 3/27/13 3:20 PM, Bob Camp wrote:
Eight ohms at 28 volts would be just a bit under 4 amps. It's also
right at 100 watts. I'd be very surprised it you need anywhere near
that much current. You probably want a pure sine wave to keep
everything happy. A lot of the simple inverters are "sort of" sine
waves. I think I'd vote for something like an cheap audio amp driven
by a nice clean / stable 400 Hz tone.
So, if I take my nice clean 10 MHz, rig up a counter that counts to
25,000, and a suitable PROM and DAC... (or run a DDS chip)... I think
that would be a "clean and stable" 400 Hz.
Of course, for the more mechanically inclined.. what about a big
flywheel driving an alternator. You might be able to rejigger a car
alternator. I don't recall how many poles they have..you might have to
spin it pretty fast.
On Mar 27, 2013, at 22:54, Jim Lux jimlux@earthlink.net wrote:
On 3/27/13 3:20 PM, Bob Camp wrote:
Of course, for the more mechanically inclined.. what about a big flywheel driving an alternator. You might be able to rejigger a car alternator. I don't recall how many poles they have..
A motor driving a flywheel driving an alternator/generator is called a motor generator set. Some implementations are called a diesel electric locomotive. We used to use them as power conditioners for Cray class supercomputers. Also used by many home machinists to generate 3 phase from single phase power.
Car alternators are generally 3 phase internally. Don't know if you could get 28vac out tho.
If you need good 3 phase 400 Hz you can get a VFD which goes up that high and
program it to just sit there making 400 Hz.
On 3/27/2013 11:16 PM, bownes wrote:
On Mar 27, 2013, at 22:54, Jim Lux jimlux@earthlink.net wrote:
On 3/27/13 3:20 PM, Bob Camp wrote:
Of course, for the more mechanically inclined.. what about a big flywheel driving an alternator. You might be able to rejigger a car alternator. I don't recall how many poles they have..
A motor driving a flywheel driving an alternator/generator is called a motor generator set. Some implementations are called a diesel electric locomotive. We used to use them as power conditioners for Cray class supercomputers. Also used by many home machinists to generate 3 phase from single phase power.
Car alternators are generally 3 phase internally. Don't know if you could get 28vac out tho.
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No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1430 / Virus Database: 2641/5707 - Release Date: 03/27/13
Crikey - an alternator?
Automotive alternators typically have 6 poles, which delivers
60 Hz at 1200 RPM. You would need to go to 8000 RPM to get 400
Hz, or a bit more than 133 revs per second. That's really
humming along.
When I was younger, and found a tank gyro about 3" in diameter,
it needed 115 VAC 3 phase. I found an electronic 28 VDC to 115
VAC 400 Hz that was single phase. A capacitor to the third phase
wire would spin it up after you started it by hand.
The motor doesn't care if the excitation is sine or square. There
is a bit more heat dissipation from the harmonics in the square
wave, but nothing to worry about in a small motor. If you are a
purist, as many list members are, you could build a six step
inverter to cut down on the harmonics.
To be practical, divide 10 MHz from a GPS disciplined oscillator
(which is necessary to be talking about this in this group),
use a transistor to switch any available DC into a suitable audio
transformer, and resonate it to 400 Hz with some caps.
There was a time when I'd have killed for that kind of souvenir
from a Northwest aircraft, but now I just sit back and read about
it with fading interest.
Bill Hawkins
Hi Bill,
Well, I can come up with something topical, read on. :)
[snip]
Topical in a more abstract way, strapdown systems really are very
interesting. They require precise integration of the rate output over
time to derive velocity and position, and really weren't practical until
the 70's when small enough computers existed to do the requisite
calculations. (I worked on the nav system for the Trident missile back
in my Draper Labs days).
Well, for the analysis of your gyro performance, time-nuts are already
equiped with one of the tools used - the Allan Variance.
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4404126&tag=1
There is also the relation
GPS & oscillator -> GPSDO
where in the navigation field
GPS & 3x gyro + 3x accel -> GPS stabilised inertial navigation
system
--
Björn
Just an idea -- if 440 Hz would work, there are a lot of electronic tuning
fork circuits out there.
Here is one:
http://www.spaennare.se/tfork.html
You could choose another crystal frequency or divide-by ratio if it needs to
be 400.00
Add a phase-shift circuit to get the other two phases (if needed),
amplifiers and you are good to go.
Dave
-----Original Message-----
From: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] On Behalf Of bg@lysator.liu.se
Sent: Thursday, March 28, 2013 05:48
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] OT - DC-10 gyros
Hi Bill,
Well, I can come up with something topical, read on. :)
[snip]
Topical in a more abstract way, strapdown systems really are very
interesting. They require precise integration of the rate
output over
time to derive velocity and position, and really weren't
practical until
the 70's when small enough computers existed to do the requisite
calculations. (I worked on the nav system for the Trident
missile back
in my Draper Labs days).
Well, for the analysis of your gyro performance, time-nuts are already
equiped with one of the tools used - the Allan Variance.
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4404126&tag=1
There is also the relation
GPS & oscillator -> GPSDO
where in the navigation field
GPS & 3x gyro + 3x accel -> GPS stabilised inertial
navigation
system
--
Björn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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