Today's Message Index:
----------------------
1. 04:20 AM - TruTrak - Was: Re: Glass Panel Layout and (BobsV35B@aol.com)
2. 05:01 AM - Re: TruTrak - Was: Re: Glass Panel Layout and (Ken)
3. 05:05 AM - Avionics Stack - Single Point Grounding... (Don Honabach)
4. 05:41 AM - Re: TruTrak - Was: Re: Glass Panel Layout and (Alex Peterson)
5. 06:13 AM - Re: Avionics Stack - Single Point Grounding... (Brian Lloyd)
6. 06:13 AM - Re: TruTrak - Was: Re: Glass Panel Layout and (Mickey Coggins)
7. 06:45 AM - Re: Avionics Stack - Single Point Grounding... (Fiveonepw@aol.com)
8. 07:13 AM - Re: Kitfox Spar Damage (Tinne maha)
9. 07:19 AM - AMP CPC connector help (John Schroeder)
10. 07:23 AM - Re: TruTrak (Robert L. Nuckolls, III)
11. 07:33 AM - Re: Avionics Stack - Single Point Grounding... (FLYaDIVE@aol.com)
12. 07:48 AM - Re: AeroElectric-List Digest: 26 Msgs - 06/24/06 (Ernest Christley)
13. 08:44 AM - Re: Avionics Stack - Single Point Grounding... (John W. Cox)
14. 11:18 AM - Re: Ray Allen Trim Servo Wiring (Joe Dubner)
15. 11:57 AM - Re: Avionics Stack - Single Point Grounding... (LarryRobertHelming)
16. 01:18 PM - Re: Re: Ray Allen Trim Servo Wiring ()
17. 02:09 PM - Re: Avionics Stack - Single Point Grounding... (FLYaDIVE@aol.com)
18. 02:09 PM - Re: Avionics Stack - Single Point Grounding... (FLYaDIVE@aol.com)
19. 02:34 PM - Re: Avionics Stack - Single Point Grounding... (FLYaDIVE@aol.com)
20. 03:42 PM - Re: Re: Ray Allen Trim Servo Wiring (Carl Morgan)
21. 04:38 PM - Re: Avionics Stack - Single Point Grounding... (Doug Windhorn)
22. 06:14 PM - Re: Avionics Stack - Single Point Grounding... (Brian Lloyd)
23. 06:25 PM - Re: Re: Ray Allen Trim Servo Wiring (Brian Lloyd)
24. 06:25 PM - Re: TruTrak - Was: Re: Glass Panel Layout and (Alex Peterson)
25. 06:57 PM - Re: Re: Ray Allen Trim Servo Wiring (Robert L. Nuckolls, III)
26. 07:21 PM - Re: Avionics Stack - Single Point Grounding... (George Nolin)
27. 07:33 PM - Re: Avionics Stack - Single Point Grounding... (Don Honabach)
28. 11:00 PM - Re: Re: Ray Allen Trim Servo Wiring ()
Message 1
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Subject: | Re: Glass Panel Layout and |
Good Morning Ed,
That is a possibility!
Thank you for bringing it to our attention. It IS the way of the future.
Jim has done wonderful things.
Have you ever talked to him about the FAA? As I am sure you are aware, he
has often stated that he hopes to never deal with a FED again!
When he first developed the original version of the TruTrak, I naively aske
d
him how it worked. His answer: ---- "GOOD!"
When I continued to press, he said he didn't care what made it work, all he
cared about was that it provided a plus or minus five volts and that was wha
t
he needed to make his autopilot work.
True Genius!
I do not mean to infer that Jim does not really know how the accelerometers
work, he was just emphasizing the point that I didn't really have to
understand it to trust it.
Hopefully, his innovations will eventual drift over to certificated aircraf
t.
Brian mentioned the rate problems which are bothering the FAA. It is awfull
y
hard to get them to accept anything new.
There is no doubt that if I were flying an experimental airplane, I would
have one of Jim's autopilots hooked up as a full time aid in much the same
manner as Mooney used some thirty years ago. It was on full time and you had
to
hold down a button to get rid of it.
That did not work as well as one might hope it would. I do believe further
research is needed to see how best to interface the autopilot and the human
pilot.
As electronic aids improve, the man/machine interface has to change.
Air Bus is trying to make it work. Most of the pilots flying that machine
are happy with it, though I do know a few pilots who have bid off because th
ey
did not feel the pilot had adequate control or they did not care for the
man/machine interface.
Boeing has taken a different tack, but they claim keeping the interface
desired by the pilots has cost them one hundred and seventy pounds of payloa
d.
That is enough to carry one more passenger.
It may be that pilots who truly understand the workings of a computer can
accept giving control of their lives to it while pilots who do NOT understa
nd
computers are hesitant to do so.
Since I am strictly a computer and electronics illiterate, I would probably
add an ancient T&B "Just In Case!"
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
In a message dated 6/25/2006 11:38:08 P.M. Central Standard Time,
bicyclop@pacbell.net writes:
Bob et al,
You might take a look at the pictorial turn & bank here:
_http://www.trutrakflightsystems.com/ttfsinstruments.html_
(http://www.trutrakflightsystems.com/ttfsinstruments.html)
It=99s sorta like a turn & bank and a turn co-ord together only the h
orizon
doesn=99t act backwards to what the horizon does, and all based on an
electronic
gyro. You can get it combined with a one or two axis AP if you want.
See:
_http://www.trutrakflightsystems.com/ttfsproducts.html_
(http://www.trutrakflightsystems.com/ttfsproducts.html)
I haven=99t flown one and so can=99t comment on the usability c
ompared to iron
turn & bank.
Pax,
Ed Holyoke
Message 2
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Subject: | Re: Glass Panel Layout and |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Or it could be exactly the reverse!
But that's a different topic for a different place and it is largely a
software issue...
Ken
> It may be that pilots who truly understand the workings of a computer
> can accept giving control of their lives to it while pilots who do NOT
> understand computers are hesitant to do so.
>
Message 3
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Subject: | Avionics Stack - Single Point Grounding... |
I'm trying to wrap my mind around the single-point grounding system as
described in the 'Connection, in particular as it affects devices in the
avionics stack.
If I understand the core process, you go ahead and bring all power
grounds for cockpit related equipment to a single termination point on
the firewall (i.e. the fast tab ground plane). What I'm a bit confused
about though is that a prior post mentioned that most avionics run an
internal ground to their case. For metal planes using metal panels and
metal mounts wouldn't this result in a dual ground system (and as such
potential result in ground loop issues)? If so, does this mean that I
should go ahead and insulate items in the panel that might have a
noticeable affect (radios, intercom, etc.) or ???
(Thanks in advance for any help and guidance!)
Thanks,
Don
Message 4
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Subject: | Re: Glass Panel Layout and |
I'm hopping in to the middle of this, so apologies if I'm repeating old
ground.
My thoughts on the human/airplane interface is that computers are better at
watching people than the other way around. A computer doesn't mind watching
a pilot for hours on end, and is ready in an instant to warn the pilot or
take over. From my limited understanding, it seems that in modern airliners,
the pilots are expected to watch the computer, but be ready in an instant
should the need arise.
I would think that a truly innovative approach to avionics in light
airplanes would be something similar to what, I understand, some military
fighters have had for quite some time. That is, the autopilot takes over if
a crash is imminent. It seems that having some solid state (yes, they are
rate based) gyros being watched in conjunction with the gps terrain data
base would not be that difficult (at least for experimentals).
We'd have to have some sort of "Press to Buzz" switch on the stick to
override this function:^)
Alex Peterson
RV6-A N66AP 762 hours
Maple Grove, MN
_____
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
BobsV35B@aol.com
Sent: Monday, June 26, 2006 6:12 AM
SNIP
As electronic aids improve, the man/machine interface has to change.
Air Bus is trying to make it work. Most of the pilots flying that machine
are happy with it, though I do know a few pilots who have bid off because
they did not feel the pilot had adequate control or they did not care for
the man/machine interface.
Boeing has taken a different tack, but they claim keeping the interface
desired by the pilots has cost them one hundred and seventy pounds of
payload. That is enough to carry one more passenger.
It may be that pilots who truly understand the workings of a computer can
accept giving control of their lives to it while pilots who do NOT
understand computers are hesitant to do so.
Since I am strictly a computer and electronics illiterate, I would probably
add an ancient T&B "Just In Case!"
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
Message 5
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Subject: | Re: Avionics Stack - Single Point Grounding... |
On Jun 26, 2006, at 8:02 AM, Don Honabach wrote:
> For metal planes using metal panels and metal mounts wouldn=92t this
> result in a dual ground system (and as such potential result in
> ground loop issues)? If so, does this mean that I should go ahead
> and insulate items in the panel that might have a noticeable affect
> (radios, intercom, etc.) or ???
Go ahead and ground the cases of your avionics. The issue comes when
you are doing signal grounds, mostly mic wiring. There you want to
have a single ground point for sure and it should be at your audio
panel or intercom.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
=97 Antoine de Saint-Exup=E9ry
Message 6
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Subject: | Re: Glass Panel Layout and |
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
> It may be that pilots who truly understand the workings of a computer
> can accept giving control of their lives to it while pilots who do NOT
> understand computers are hesitant to do so.
Hi Bob,
I think I would modify this just a bit.
Pilots who *think* they understand computers will trust their
lives to them, and pilots who truly *do* understand computers
will not.
Of course, it's all about risk management. I've been working
with computer hardware and software since the 70s, both for
fun and food, and I've seen the full range of good and bad
programming and hardware design. There are computer systems
that I would trust more than the random human, but I would
never trust just any ol' computer system with my life.
As applied to aviation, computer systems can add a lot of
value, and increase safety. Some airplanes require computer
systems to fly. A pilot should never blindly *trust* these
systems. They should spend time understanding them, learning
about their strengths and weaknesses, and learning how to
handle their failure modes.
This is no different from using mechanical instruments in
the cockpit. When we are trained to use gyros, we are taught
how to deal with the case where they fail. Computers fail
too, people need to be taught how they may fail, how to
recognize the failure, and what to do about it. They
should not be simply told that they can't fail, and that
they should blindly trust them.
> Since I am strictly a computer and electronics illiterate, I would
> probably add an ancient T&B "Just In Case!"
Wise move. Several systems using different technologies from
different suppliers will give you the best chance of surviving
a failure. We hear about this sound philosophy on this list
all the time. Ensure that the failure of any one system will
not cause a forced landing - or worse. Where you do have
single systems (engine, for example) be extra diligent about
maintenance.
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
Message 7
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Subject: | Re: Avionics Stack - Single Point Grounding... |
In a message dated 6/26/06 7:09:07 AM Central Daylight Time,
don.honabach@pcperfect.com writes:
> I=99m trying to wrap my mind around the single-point grounding syste
m as
> described in the =98Connection, in particular as it affects devices
in the avionics
> stack.
>>>>
Some EE out there will undoubtedly correct me, but this is how I look at it:
Electrons come screaming out of the battery up an interstate highway of
copper wire to each device. Once being tortured therein, they must return t
o the
fold (battery). Given the choice of a return Interstate highway of more
copper, or "over the river & thru the woods (device chassis, screws, metal m
ashed to
other metal etc.- just think HIGHER RESISTANCE than the highway) they will
prefer the easier route- one that is just as easy going as coming. When all
electrons travel this way, they are happy electrons and are less likely to
insidiously attack your ears as noyz! 8-)
(and yeah, I know about "holes" but let's KIS)
Mark - purty darn quiet Z-11 RV-6A
do not archive unless this adds something to the discussion or I case I'm
just plain wrong!
Message 8
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Subject: | RE: Kitfox Spar Damage |
--> AeroElectric-List message posted by: "Tinne maha" <tinnemaha@hotmail.com>
Hi Dave,
Not sure what model your Kitfox is........I've got an untouched set of
skystar built wings that are rated for a 1,400 lb gross weight. They came
with my series 5 in 1995 but I upgraded to the 1,550 lb wings later. They
have been hanging from a ceiling or in the shipping box my new wings came in
ever since.
I am firm at $2,000 + shipping costs.
Let me know if you are interested.
Grant
Message 9
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Subject: | AMP CPC connector help |
--> AeroElectric-List message posted by: "John Schroeder" <jschroeder@perigee.net>
Erich -
Buy the AMP CPC Type 2. Allied is a good source and they no longer have a
min. $ amount per order.
Buy the gold plated pins size 20 pins from either Steinmark or B&C and the
crimper from B&C. Stein may also carry the crimper. We used this combo on
the CPC's for the panel and for the DB9's on the autopilot sevros and DB25
for the Tru Trak box itself.
Piece of cake to get good crimps. The pins are good for 20 - 26 AWG and
although they are a bit more expensive, they are mil-spec and for avionics,
that is what is best.
Cheers,
John Schroeder
Lancair ES - about ready to fly.
Message 10
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
I'll suggest that it's more rudimentary.
Success in any endeavor is based on assembling a collection of simple-ideas
into an invention that is refined over time and experience while respecting
the laws of optimum proportionality to achieve a recipe for success. If we
look back over the history of flight, we'll find many examples of shaky
technology and process that would scare today's pilots away. History is
replete with accounts by early barnstorming pilots who dealt with
relatively fragile, life limited, less than optimal features in their
airplanes. Repairs were often made with tools carried in the airplane using
materials obtained from local merchants. Most repairs were made to correct
LIFE-LIMITED features as opposed to damage. Today, our high risk concerns
for flight are centered around HOW we operate the airplane. Back then, a
much higher percentage of pilots died because some part of the airplane
failed. Read Lindbergh's account of how the Spirit of St. Louis came into
being. The long pole in his tent was the engine. Recall that his flight was
only 23 years after the Wright brothers struggled into the air with an
extremely fragile, horribly underpowered airframe with dynamic stability
issues designed to bend airplanes and break pilots.
Some things evolve faster than others and the rate of evolution is based on
individual perceptions of opportunity to address a market. As I've written
in other posts, the state of our technical and manufacturing skills today
runs far ahead its application in airplanes. Way too much of how we think
about flying is rooted in our experience which has been hamstrung with the
albatross of regulation teamed with industry's misguided worship of policy
and procedure. While computers, automobiles, even toasters and VCRs become
more capable, less expensive to build and more reliable every year,
on-board systems in our airplanes lag further and further behind.
When one speaks of potentially life saving features that could be developed
for airplanes exploiting all that mankind knows how to do, there will
always be the individual who points a finger a Bill Gates and announces
that he'd never put his life in the hands of that man's software. But
consider the two missions: Bill's products require millions of lines of
code and thousands of programmers to develop an operating system that runs
hundreds of applications in hardware he has little direct control over.
From our perspective as users of airplanes and developers of hardware to
meet market needs, the task of crafting potentially life saving hardware is
perhaps 1/10,000 the size of Bill Gate's task.
A sold state rate sensor ($30), a GPS engine ($30), a stepper motor ($15),
a two gears and a rudimentary gear box combined with a CPU ($2) and a
hand-full of jelly-bean parts will run a few dozen lines of assembler code
that would offer a pilot 99% of everything he wants a "hands off flight"
system to do when thing are turning to crap in the cockpit. The thing that
makes this system stand far above Bill's products for reliability is low
parts count, low line count in code, low stress levels in components,
readily available off-the-shelf components and a SIMPLE SINGLE MINDED TASK
for functionality - hold a course.
Once this rudimentary "hammer" is crafted and installed, a marketer/user
has a means by which a whole lot of features can be added. A palm top could
be programmed to do all manner of navigational assist tasks by feeding new
course commands to the gps-aided wing leveler. The high risks are all
herded into one piece of low cost hardware (the palm top) that can be
totally disconnected from the wing-leveler at any time without crippling
the wing-leveler's ability to save your life. Under those conditions,
perhaps running Bill's software in your airplane becomes less problematic.
Installing two such systems powered from separate sources begins to offer
hands-off-flight stability with the same order of system reliability as
prop bolts.
We can debate the sensor-display-interpretation-reaction servo-loop for
flying forever but no combination of hardware -AND- pilot will match up to
the capabilities of what some simple hardware and yes, even Bill's
software, can do for us to avoid top billing on an NTSB accident
report. Accidents are unintended consequences over which victims have no
control when events stack up beyond some tipping point. Every prudent and
insightful designer should be working toward solutions that make tipping
points harder to reach. 75 years ago pilots were till very much at-risk of
tipping events forced upon them by limits in technology and process; their
demise was properly called an "accident".
Today, we're subject to tipping events that are NOT products of limits to
the best-we-know-how-to-do. They are the unintended consequences of those
who say they're keeping us "safe" from ourselves and our airplanes. In
fact, they have become the biggest promoters of disasters waiting to
happen. If one takes to the race track today with Firestone 500 nylons and
asbestos lined brakes, any demise to the car or driver precipitated by the
failures of those two systems to perform would not be called and accident.
Whether you talking race cars or airplanes, the consequences of not
exploiting the best-we-know-how-to-do are not accidents, they're EXPECTED
RESULTS of ignorance and failure to exploit man's natural desire to survive
and his inherent abilities to improve on that condition if individuals with
with airs of authority are not standing in the way saying, "you can't do that".
This cannot be laid just at the feet of the regulators. Leaders in the
aviation industry have become totally uprooted from the mind set that made
Beech, Lear, Cessna, et als. the once-great icons of aviation progress. If
there's a bright star on the horizon for little airplanes, it's shining
into basements and garages of all you folks who have "disconnected" from
the impediments to progress that are killing type certificated aviation.
The airplanes with the highest return on investment for safety and utility
will be the ones you folks are building.
Bob . . .
08:01 AM 6/26/2006 -0400, you wrote:
>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
>Or it could be exactly the reverse!
>
>But that's a different topic for a different place and it is largely a
>software issue...
>
>Ken
>
>>It may be that pilots who truly understand the workings of a computer can
>>accept giving control of their lives to it while pilots who do NOT
>>understand computers are hesitant to do so.
>>
>
>
>--
>No virus found in this incoming message.
>
>
>-- incoming mail is certified Virus Free.
>Checked by AVG Anti-Virus.
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 11
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Subject: | Re: Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 6/26/06 8:09:07 AM Eastern Daylight Time,
don.honabach@pcperfect.com writes:
> For metal planes using metal panels and
> metal mounts wouldn't this result in a dual ground system (and as such
> potential result in ground loop issues)? If so, does this mean that I
> should go ahead and insulate items in the panel that might have a
> noticeable affect (radios, intercom, etc.) or ???
>
>
>
> (Thanks in advance for any help and guidance!)
>
>
>
> Thanks,
>
> Don
=============================
Don:
You bring up one of my pet peeves ... GROUND LOOPS!
99.99% of the electrically involved do not understand ground loops. Due to
the Internet, rumors and BS spread at the speed of an electron.
A single point ground is a good thing. We ARE talking about DC (Battery)
circuits, right? But we are also talking about PLANES. And in Composition
Planes you MUST bring your ground to where ever you need it. In metal - aluminum
planes there is the possibility of using the plane as a ground. Just like they
do with cars. The problem is aluminum is a very poor electrical conductor
and a very good developer of corrosion.
OK, here are the Questions and the Answers:
As you mentioned Radios can use their CASE as the GROUND conductor.
Is that the way to go?
A: NO! And below are the reasons
Is there a problem with that?
A: YES - The radio is NOT a solid mechanical connection its movement makes
for a POOR Ground. When it moves it creates ware points on the case and tray
which remove the anodizing which increase the chance of corrosion. And in
return a POORER Ground.
Will it create a Ground Loop?
A: Well, lets ask the question: What is a Ground Loop?
There are TWO different types of Ground Loops ... AC & DC.
AC is anything with an Alternating Current that has a Frequency (i.e.: AF -
AUDIO and RF - Radio Frequencies. More on this later.
DC is Direct Current and does NOT have a frequency or a pulse, Your Planes
Battery / Alternator System.
A ground Loop in a DC circuit happens when there is a Potential Difference
between what should be Common Ground points.
Why are they NOT COMMON?
A: Because there is some form of resistance that causes the Potential
Difference (I.e.: Corrosion or Long Runs of Ground wire of the WRONG SIZE.
Can I use a separate Ground?
A: HELL YES! The issue is NOT how many grounds you have but the QUALITY of
the grounds.
If you use a single point ground to say an aluminum firewall and the area
under the Nut & Bolt ... You did use a Nut & Bolt? ... Corrodes ALL of your
grounds to that tie point are now at risk. To this add a bit of voltage and the
corrosion will increase. If it IA an aluminum point the corrosion is Aluminum
Oxide and Aluminum Oxide is pretty damn close to an insulator.
Should I use an ADDITIONAL separate Ground?
A: What do you think after reading the above Q&A?
The answer should be YES!
Keeping the potential difference on the Ground side of the circuit as low and
as uniform as possible should be your goal. It will help in the operation of
the equipment and eliminate failure points as well as NOISE.
Ok, now onto AC - AF & RF
The basic rule is very simple, learn it and don't forget it:
With an AF circuit you ONLY GROUND at the Source of the AF.
Lets consider intercoms. 99.99% of the noise problem is because someone,
somewhere in the installation GROUNDED the SHIELD at BOTH ENDS of the run. It
should be grounded where? At the Source ... At the Intercom. NOT at the Mic or
Phone jack.
Now someone is going to say ... Mine is grounded at both ends and it works
fine. Take a close LQQK I'd bet there are plastic mountings around the jacks.
Ok, now onto RF
The basic rule is very simple, learn it and don't forget it (where have you
heard that before):
With an RF circuit you GROUND at BOTH ends.
Both the Source (Radio) and Load (Antenna).
Question: What kind of a device is a STROBE?
A: It is both an AF and RF device.
The major part of the strobe noise is in the AF range.
Long runs of Power Lines to the Strobe and Flash Tube lines help to spread
the noise around. Because the expanding and collapsing fields of the strobe the
enegery/noise can be transmitted just like an RF signal. Transmitted into
other wires and down power lines. This is heard as noise in the headsets.
Question: How do you lessen or eliminate this noise?
Answer: Since it is both AF & RF you have to experiment. Use Shielded wire
for your power (B+) lines. Start by grounding at the source. Leave some
shielded ground free at the far end. Use Tolroids (ferrite beads) on the Power
and
Flash Tube wires. Give it a test ... Try grounding the free end shield. Do
Not run strobe lines parallel to other wires or antennas.
There are other tricks but these are the basics that handle most of the
problems.
So, do I believe in Single Point Grounds? Yes, a whole lot of them!
So, do I believe in DC Ground Loops? Yes, ONLY if you have POOR GROUNDS!
<<<--- Keyword - letter - being 'S' - GROUNDS
Barry
"Chop'd Liver"
Message 12
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Subject: | Re: AeroElectric-List Digest: 26 Msgs - 06/24/06 |
--> AeroElectric-List message posted by: Ernest Christley <echristley@nc.rr.com>
AeroElectric-List Digest Server wrote:
>The AI NEVER stabilizes there is a slow tumble until I see either nothing but
>sky or ground. NEVER STABILIZING!
>
>Has anyone ever run across this problem and if so what was the cause and cure?
>
>It has been suggested that I perform two (2) operations:
>1 - Upgrade the Software from Ver 2.21 to Ver 2.64
>2 - Hook up the keyboard and do a Warm System reboot from the keyboard
>
>What are your thoughts? Does this sound like a cure? Of course the software
>upgrade is required and will be done.
>
>Barry
>"Chop'd Liver"
>
>
>
I work in the software industry as a Quality Assurance Engineer, ie. I
test software. I've written a lot of software. I've met a lot of
software engineers. I've worked worked for several software companies.
There is a wide range of attitudes when it comes to software.
At one end of the spectrum is the companies/engineers that treat
software and the requisite hardware as an appliance. The software is
tied intimately to the hardware, and a breakage in one signifies a
breakage in the other. A breakage in either signifies a breakage in the
organization. Code is meticulously maintained, and every last detail of
the software/hardware combination is tested as much as humanly possible
before shipping to the customer. The engineers tend to be very
experienced and 'slow moving'. The code is not expected to break when
delivered to QA. The best example I have personal experience with is
IBM's mainframe networking division.
The other end of the spectrum is what I like to call "The Microsoft
Generation". Code is whipped out using long tool chains built on top of
libraries written by someone else. I meet lots of these engineers
building database frontends to generate reports to management. The
criteria for these engineers is that they generate a disposable app
quickly and move on to the next project. They are conditioned to value
a new glitzy widget over solid engineering. Code unit test is an
afterthought at best, and if it does happen it consist of being able to
generate a report on a couple sets of data at most. These guys deliver
stuff to QA with the idea that the test team will tell them what is
wrong with the code. I call it the Microsoft Generation, because that
company has be the forerunner in preaching that hiring competent,
seasoned engineers is uneccessary with their software. Software is
complex and should be expected to break, they preach, but their tool set
will enable a cheap college grad that will work around the clock for
Coke and pizza to spit out polished applications to run the enterprise.
Widget, "new features" and just more eye-candy can be added ad nauseum,
quickly and easily.
The Microsoft Generation is OK for generating reports to management.
I'll even abide letting them build a video game or two. But I want real
engineers writing any software that I will be letting my butt ride on.
I talked to Blue Mountain and Dynon at Sun-n-Fun. The question I had in
mind was, "If I were an QA engineer at this company, what would the
development team deliver to me for testing?" The Dynon unit booted
quickly and showed a simple display. I got the "feel" that the software
was written for the hardware, and the hardware was designed for the
software. The BMA unit seemed to take for ever to boot up, complete
with splash screen to keep the user occupied reading copyright
information while it did a digital dance behind the scenes. (BTW, a
"splash screen" is a red flag that someone from the Microsoft Generation
is behind the scenes. How is it helpful, except to show more
eye-candy? And copyright? What am I going to do, run the stuff on my
PC?) I got the distinct feeling that BMA engineers would expect me to
tell them what was wrong with it, while the Dynon folks would only
expect me to verify that it works as they designed it.
My thoughts? The fact that the BMA is designed for "quick upgrades" is
a glaring red flag. The thing is a limited function device. It should
work out of the box. The in-field "quick upgrade" tells me that BMA is
using you as a beta tester. The fact that it doesn't work out of the
box tells me that either the hardware or software is broken. Being that
this is the real world, I can accept hardware being broken. Things
break in shipping...not every IC is tested off the assembly line..etc.
But the fact that a 'software fix' is available gives me the thought
that the development organization needs a fix.
--
,|"|"|, Ernest Christley |
----===<{{(oQo)}}>===---- Dyke Delta Builder |
o| d |o http://ernest.isa-geek.org |
Message 13
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Subject: | Avionics Stack - Single Point Grounding... |
I am no EE but in A & P school they were quite clear that electrons come
from the negative terminal. That is why the positive is always
connected first and the negative terminal is connected last. The better
the negative (Ground) path - "Path of least resistance" .... I know a
straight line between two points. The electrons will always chose the
lazy way. Still an important idea for high quality ground connections.
John Cox - $00.02
________________________________
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Fiveonepw@aol.com
Sent: Monday, June 26, 2006 6:40 AM
Grounding...
In a message dated 6/26/06 7:09:07 AM Central Daylight Time,
don.honabach@pcperfect.com writes:
I'm trying to wrap my mind around the single-point grounding system as
described in the 'Connection, in particular as it affects devices in the
avionics stack.
>>>>
Some EE out there will undoubtedly correct me, but this is how I look at
it:
Electrons come screaming out of the battery up an interstate highway of
copper wire to each device. Once being tortured therein, they must
return to the fold (battery). Given the choice of a return Interstate
highway of more copper, or "over the river & thru the woods (device
chassis, screws, metal mashed to other metal etc.- just think HIGHER
RESISTANCE than the highway) they will prefer the easier route- one that
is just as easy going as coming. When all electrons travel this way,
they are happy electrons and are less likely to insidiously attack your
ears as noyz! 8-)
(and yeah, I know about "holes" but let's KIS)
Mark - purty darn quiet Z-11 RV-6A
do not archive unless this adds something to the discussion or I case
I'm just plain wrong!
Message 14
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|
Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: Joe Dubner <jdubner@yahoo.com>
Answering my own question here so that others may profit from my
research ...
I just got off the phone with Scott at RAC and he confirmed that two (or
any number) of trim switches can be connected to each input wire of a
relay deck. No isolation diodes are used with SPST switches to ground.
There is no inherent danger in activating multiple trim switches
simultaneously. And grounding both relay deck input wires
simultaneously will provide no output to the trim servo, just as if no
switch was activated.
Note that this information applies to an installation that uses two G305
Stick Grips, two REL-1 Servo Relay Decks, and two T2-7A servos. It does
not necessarily apply to *all* RAC trim installations. For example, the
RAC website shows a wiring diagram for RS2 Rocker Switches that requires
isolation diodes unless the RS2 switches are rewired in some unspecified
fashion. See http://www.rayallencompany.com/RACmedia/instructionstwoRS2.pdf
There's a lot of misinformation floating around. When I spoke with
Scott I made a pitch for including real schematic diagrams of their
components (rather than a bewildering array of wiring diagrams) so one
could properly analyze their operation without spending a lot of effort
reverse engineering or making so many assumptions. I don't think he was
convinced so I'd urge anyone else who has opportunity to ask RAC a
question to make the same request.
--
Joe
On 10-Jun-06 14:40 Joe Dubner wrote:
> Can anyone shed some light on a question about the use of two Ray Allen
> Company control stick grips with trim switches, two RAC relay decks, and
> RAC servos for aileron and elevator trim? The RAC "Wire schematic" is
> attached.
>
> Do both sets of trim switches (the corresponding switches from grip 1
> and grip 2) connect to the points labeled Switch 1, Switch3, Switch4,
> and Switch2? To me the diagram doesn't make this clear.
>
> Does anyone have a schematic diagram of a complete RAC trim system that
> includes relay deck(s) and indicator(s)? The RAC documentation spreads
> out the applicable information between the stick grip and the servo
> manuals and it is more of a pictorial than a schematic diagram. I'd
> particularly like to see what's inside the "relay deck".
>
> Thanks,
> Joe
>
> -----------------------------------------------------------------------
> Joe Dubner K7JD | 523 Cedar Avenue | users.lewiston.com/hth/jd/
> Long-EZ 821RP | Lewiston, ID 83501 | +1 208 305-2688
> -----------------------------------------------------------------------
Message 15
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|
Subject: | Re: Avionics Stack - Single Point Grounding... |
I understand what you are saying John about connecting the negative
last. I however do it that way because if connecting the positive last,
you could easily ground the positive to some part of the plane when
connecting the positive. If the negative is connected last as you
suggest, touching the airframe while fastening the positive or negative
terminal does not cause sparks to fly. Knowing what I know about
electronics, I still am not sure if the electrons flow from negative to
positive or the holes left by the jumping electrons. Let the debate
begin. Larry in Indiana
----- Original Message -----
From: John W. Cox
To: aeroelectric-list@matronics.com
Sent: Monday, June 26, 2006 10:40 AM
Subject: RE: AeroElectric-List: Avionics Stack - Single Point
Grounding...
I am no EE but in A & P school they were quite clear that electrons
come from the negative terminal. That is why the positive is always
connected first and the negative terminal is connected last. The better
the negative (Ground) path - "Path of least resistance" .. I know a
straight line between two points. The electrons will always chose the
lazy way. Still an important idea for high quality ground connections.
John Cox - $00.02
-------------------------------------------------------------------------
-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Fiveonepw@aol.com
Sent: Monday, June 26, 2006 6:40 AM
To: aeroelectric-list@matronics.com
Subject: Re: AeroElectric-List: Avionics Stack - Single Point
Grounding...
In a message dated 6/26/06 7:09:07 AM Central Daylight Time,
don.honabach@pcperfect.com writes:
I'm trying to wrap my mind around the single-point grounding system as
described in the 'Connection, in particular as it affects devices in the
avionics stack.
>>>>
Some EE out there will undoubtedly correct me, but this is how I look
at it:
Electrons come screaming out of the battery up an interstate highway
of copper wire to each device. Once being tortured therein, they must
return to the fold (battery). Given the choice of a return Interstate
highway of more copper, or "over the river & thru the woods (device
chassis, screws, metal mashed to other metal etc.- just think HIGHER
RESISTANCE than the highway) they will prefer the easier route- one that
is just as easy going as coming. When all electrons travel this way,
they are happy electrons and are less likely to insidiously attack your
ears as noyz! 8-)
(and yeah, I know about "holes" but let's KIS)
Mark - purty darn quiet Z-11 RV-6A
do not archive unless this adds something to the discussion or I case
I'm just plain wrong!
Message 16
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|
Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
Just some very basic information about Ray Allen Servos (or other DC Brush
Motors) that if you don't know, you should:
The motors used on my T4-5 and whatever model a Europa uses for pitch
(with indicator) are simple brush motors.
Reverse the polarity of the 2 wires going to the motor, and the motor
reverses.
If you connect the 2 wires going to the motor to each other, it will act
as a brake. In other words if the motor is spinning and you disconnect
power, you are relying on the drag from brushes, gears and load to stop
the motor. These brush motors are generators if you spin them. They will
slow up real quick but only if you put a load on them. Connecting the 2
leads is a good load (generator needs to work with shorted wires, thus
there is motor braking).
If you draw a schematic of what their reversible switch is doing, things
will become very clear. Specialized switch (nice job) that you need relays
to duplicate with mini stick switches.
When I was studying how to deal with switching control from left stick to
right stick for my 3 servo motors (Aileron Ray Allen, Pitch pay Allen and
Airmaster Prop) I do see that there are some installs that do not use
motor braking. I am incorporating Braking.
I went with a multi tier selector switch (will look up info if anyone is
interested in busting the budget) and 4 relays.
By using a brake, when you let go of switch there is not much in the way
of coasting. I think this will be enough control so that I will not need
to control motor speed.
Another note on controlling speed of a DC brush motor, you can just add
resistors, which will drop voltage. The motor will not develop as much
torque. Or you can install a pulse proportion electronic speed controller.
It will provide full voltage, but depending on selection will limit the on
time per second, thus slowing down the motor. Also more efficient. If you
fly model electrics you will appreciate this feature, also there is a lot
less heat developed in wasted energy (last 2 sentences same thing).
If you don't install a speed controller, it can not fail or make noise.
Last note while standing on my soap box, do not over drive throw of
whatever it is you are trying to drive. If you want 3/16 throw up and down
for roll trim tab, and you are getting 1/2 inch, besides being undesirable
in event of run away, it is working motor harder than it could, and moves
far faster than it could, and is more susceptible to stripping gears if
you have "Muppet's" (as Neville would say) bang into your tab. Increase
driven control arm, or add a intermediate long arm in, short arm out.
Off Box.
Ron Parigoris
Message 17
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|
Subject: | Re: Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 6/26/06 3:06:33 PM Eastern Daylight Time,
lhelming@sigecom.net writes:
> Knowing what I know about electronics, I still am not sure if the electrons
> flow from negative to positive or the holes left by the jumping electrons.
> Let the debate begin. Larry in Indiana
==============================
Larry:
It does not matter which horse you use to cross the stream. Just don't
change horses mid stream.
Barry
"Chop'd Liver"
Message 18
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|
Subject: | Re: Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 6/26/06 3:06:33 PM Eastern Daylight Time,
lhelming@sigecom.net writes:
> I am no EE but in A & P school they were quite clear that electrons come
from
> the negative terminal. That is why the positive is always connected first
> and the negative terminal is connected last.
========================
John:
If that is what they are teaching then have them grab +500 Volts in the Right
Hand and -500 Volts in the Left Hand and turn the switch ON.
Plus 500 added to Negative 500 is ZERO and there will be no voltage flow.
The instructor should live Right?
Barry
"Chop'd Liver"
Message 19
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|
Subject: | Re: Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 6/26/06 8:09:07 AM Eastern Daylight Time,
don.honabach@pcperfect.com writes:
> For metal planes using metal panels and
> metal mounts wouldn't this result in a dual ground system (and as such
> potential result in ground loop issues)? If so, does this mean that I
> should go ahead and insulate items in the panel that might have a
> noticeable affect (radios, intercom, etc.) or ???
>
>
>
> (Thanks in advance for any help and guidance!)
>
>
>
> Thanks,
>
> Don
=============================
Don:
You bring up one of my pet peeves ... GROUND LOOPS!
99.99% of the electrically involved do not understand ground loops. Due to
the Internet, rumors and BS spread at the speed of an electron.
A single point ground is a good thing. We ARE talking about DC (Battery)
circuits, right? But we are also talking about PLANES. And in Composition
Planes you MUST bring your ground to where ever you need it. In metal - aluminum
planes there is the possibility of using the plane as a ground. Just like they
do with cars. The problem is aluminum is a very poor electrical conductor
and a very good developer of corrosion.
OK, here are the Questions and the Answers:
As you mentioned Radios can use their CASE as the GROUND conductor.
Is that the way to go?
A: NO! And below are the reasons
Is there a problem with that?
A: YES - The radio is NOT a solid mechanical connection its movement makes
for a POOR Ground. When it moves it creates ware points on the case and tray
which remove the anodizing which increase the chance of corrosion. And in
return a POORER Ground.
Will it create a Ground Loop?
A: Well, lets ask the question: What is a Ground Loop?
There are TWO different types of Ground Loops ... AC & DC.
AC is anything with an Alternating Current that has a Frequency (i.e.: AF -
AUDIO and RF - Radio Frequencies. More on this later.
DC is Direct Current and does NOT have a frequency or a pulse, Your Planes
Battery / Alternator System.
A ground Loop in a DC circuit happens when there is a Potential Difference
between what should be Common Ground points.
Why are they NOT COMMON?
A: Because there is some form of resistance that causes the Potential
Difference (I.e.: Corrosion or Long Runs of Ground wire of the WRONG SIZE.
Can I use a separate Ground?
A: HELL YES! The issue is NOT how many grounds you have but the QUALITY of
the grounds.
If you use a single point ground to say an aluminum firewall and the area
under the Nut & Bolt ... You did use a Nut & Bolt? ... Corrodes ALL of your
grounds to that tie point are now at risk. To this add a bit of voltage and the
corrosion will increase. If it IA an aluminum point the corrosion is Aluminum
Oxide and Aluminum Oxide is pretty damn close to an insulator.
Should I use an ADDITIONAL separate Ground?
A: What do you think after reading the above Q&A?
The answer should be YES!
Keeping the potential difference on the Ground side of the circuit as low and
as uniform as possible should be your goal. It will help in the operation of
the equipment and eliminate failure points as well as NOISE.
Ok, now onto AC - AF & RF
The basic rule is very simple, learn it and don't forget it:
With an AF circuit you ONLY GROUND at the Source of the AF.
Lets consider intercoms. 99.99% of the noise problem is because someone,
somewhere in the installation GROUNDED the SHIELD at BOTH ENDS of the run. It
should be grounded where? At the Source ... At the Intercom. NOT at the Mic or
Phone jack.
Now someone is going to say ... Mine is grounded at both ends and it works
fine. Take a close LQQK I'd bet there are plastic mountings around the jacks.
Ok, now onto RF
The basic rule is very simple, learn it and don't forget it (where have you
heard that before):
With an RF circuit you GROUND at BOTH ends.
Both the Source (Radio) and Load (Antenna).
Question: What kind of a device is a STROBE?
A: It is both an AF and RF device.
The major part of the strobe noise is in the AF range.
Long runs of Power Lines to the Strobe and Flash Tube lines help to spread
the noise around. Because the expanding and collapsing fields of the strobe the
enegery/noise can be transmitted just like an RF signal. Transmitted into
other wires and down power lines. This is heard as noise in the headsets.
Question: How do you lessen or eliminate this noise?
Answer: Since it is both AF & RF you have to experiment. Use Shielded wire
for your power (B+) lines. Start by grounding at the source. Leave some
shielded ground free at the far end. Use Tolroids (ferrite beads) on the Power
and
Flash Tube wires. Give it a test ... Try grounding the free end shield. Do
Not run strobe lines parallel to other wires or antennas.
There are other tricks but these are the basics that handle most of the
problems.
So, do I believe in Single Point Grounds? Yes, a whole lot of them!
So, do I believe in DC Ground Loops? Yes, ONLY if you have POOR GROUNDS!
<<<--- Keyword - letter - being 'S' - GROUNDS
Barry
"Chop'd Liver"
Message 20
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|
Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: "Carl Morgan" <zk-vii@rvproject.gen.nz>
All great stuff - I'm going through this at the moment (yesterday).....
Questions:
The Panasonic CF2-12V relay
(http://www.naisweb.com/e/relaye/mech_eng/pdf/mech_eng_cf.pdf) is designed
for car electric windows and provides a nice twin relay (and motor
breaking - I now note), however DigiKey needs 35 as a minimum order.....
Any other leads for a similar twin option - otherwise it is 4 singles +
diodes.....
Speed control: Is it better for a low (regulated) voltage, or 12V pulsed
for a the 'slow' speed? Pro / Cons?
Thanks,
Carl
--
ZK-VII - RV 7A QB - finishing? - New Zealand
http://www.rvproject.gen.nz/
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of
> rparigor@suffolk.lib.ny.us
> Sent: Tuesday, 27 June 2006 8:14 a.m.
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Re: Ray Allen Trim Servo Wiring
>
>
> --> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
>
> Just some very basic information about Ray Allen Servos (or other DC Brush
> Motors) that if you don't know, you should:
>
> The motors used on my T4-5 and whatever model a Europa uses for pitch
> (with indicator) are simple brush motors.
>
> Reverse the polarity of the 2 wires going to the motor, and the motor
> reverses.
>
> If you connect the 2 wires going to the motor to each other, it will act
> as a brake. In other words if the motor is spinning and you disconnect
> power, you are relying on the drag from brushes, gears and load to stop
> the motor. These brush motors are generators if you spin them. They will
> slow up real quick but only if you put a load on them. Connecting the 2
> leads is a good load (generator needs to work with shorted wires, thus
> there is motor braking).
>
> If you draw a schematic of what their reversible switch is doing, things
> will become very clear. Specialized switch (nice job) that you need relays
> to duplicate with mini stick switches.
>
> When I was studying how to deal with switching control from left stick to
> right stick for my 3 servo motors (Aileron Ray Allen, Pitch pay Allen and
> Airmaster Prop) I do see that there are some installs that do not use
> motor braking. I am incorporating Braking.
>
> I went with a multi tier selector switch (will look up info if anyone is
> interested in busting the budget) and 4 relays.
>
> By using a brake, when you let go of switch there is not much in the way
> of coasting. I think this will be enough control so that I will not need
> to control motor speed.
>
> Another note on controlling speed of a DC brush motor, you can just add
> resistors, which will drop voltage. The motor will not develop as much
> torque. Or you can install a pulse proportion electronic speed controller.
> It will provide full voltage, but depending on selection will limit the on
> time per second, thus slowing down the motor. Also more efficient. If you
> fly model electrics you will appreciate this feature, also there is a lot
> less heat developed in wasted energy (last 2 sentences same thing).
>
> If you don't install a speed controller, it can not fail or make noise.
>
> Last note while standing on my soap box, do not over drive throw of
> whatever it is you are trying to drive. If you want 3/16 throw up and down
> for roll trim tab, and you are getting 1/2 inch, besides being undesirable
> in event of run away, it is working motor harder than it could, and moves
> far faster than it could, and is more susceptible to stripping gears if
> you have "Muppet's" (as Neville would say) bang into your tab. Increase
> driven control arm, or add a intermediate long arm in, short arm out.
>
> Off Box.
>
> Ron Parigoris
>
>
--
Message 21
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|
Subject: | Re: Avionics Stack - Single Point Grounding... |
Disagree, to a point. Positive should be connected before ground when
we are talking about energy sources (say battery). Why? To prevent a
short circuit. If the ground is connected first, any contact by the
positive lead will send sparks flying. If the positive is connected
first, one will be attaching the wire to a system generally at ground
potential.
This goes to the point missing from the comments below. Namely that
electrons move only when invited to do so, either when being sucked by a
higher voltage potential, or when being pushed around by electromagnetic
fields (going to stop there before revealing my ignorance about chemical
reactions, but think the voltage potential is the driving force there).
Connecting the ground first will provide a complete circuit path if the
positive terminal is shorted against the grounded environment generally
present in the airframe environment. Connecting the positive first will
only result in a ground coming in contacted with an intended grounded
airframe at the same potential, hence negligible, if any, sparks will
fly.
For energy loads (consumers), it really does not, usually, make much
difference electrically, though it could mechanically (don't have a
specific instance, just leaving the door open to avoid rebuttal on the
point). Besides, you have deenergized the potential circuit before
doing this - right?
Doug Windhorn
----- Original Message -----
From: John W. Cox
To: aeroelectric-list@matronics.com
Sent: Monday, 26 June, 2006 8:40
Subject: RE: AeroElectric-List: Avionics Stack - Single Point
Grounding...
I am no EE but in A & P school they were quite clear that electrons
come from the negative terminal. That is why the positive is always
connected first and the negative terminal is connected last. The better
the negative (Ground) path - "Path of least resistance" .. I know a
straight line between two points. The electrons will always chose the
lazy way. Still an important idea for high quality ground connections.
John Cox - $00.02
-------------------------------------------------------------------------
-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Fiveonepw@aol.com
Sent: Monday, June 26, 2006 6:40 AM
To: aeroelectric-list@matronics.com
Subject: Re: AeroElectric-List: Avionics Stack - Single Point
Grounding...
In a message dated 6/26/06 7:09:07 AM Central Daylight Time,
don.honabach@pcperfect.com writes:
I'm trying to wrap my mind around the single-point grounding system as
described in the 'Connection, in particular as it affects devices in the
avionics stack.
>>>>
Some EE out there will undoubtedly correct me, but this is how I look
at it:
Electrons come screaming out of the battery up an interstate highway
of copper wire to each device. Once being tortured therein, they must
return to the fold (battery). Given the choice of a return Interstate
highway of more copper, or "over the river & thru the woods (device
chassis, screws, metal mashed to other metal etc.- just think HIGHER
RESISTANCE than the highway) they will prefer the easier route- one that
is just as easy going as coming. When all electrons travel this way,
they are happy electrons and are less likely to insidiously attack your
ears as noyz! 8-)
(and yeah, I know about "holes" but let's KIS)
Mark - purty darn quiet Z-11 RV-6A
do not archive unless this adds something to the discussion or I case
I'm just plain wrong!
Message 22
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Subject: | Re: Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
<sigh> This thread is MUCH harder than it needs to be.
The avionics trays should be grounded. If they are in an aluminum
airplane with an aluminum instrument panel and the panel is bolted or
riveted to the airframe somehow, your job is done. If you have some
sort of nonconducting panel such that the avionics trays are
insulated from the rest of the airframe, run a wire from your
avionics tray(s) to your single-point ground.
And this has nothing to do with the power ground for the radios. Each
radio has a ground or multiple ground pins on its connector. These
should be connected to your single point ground independently of the
chassis ground.
Audio grounds, e.g. headphone, mic, audio inputs, etc., should be
isolated and go to a single point ground at the radios. Mic and
headphone jacks should be insulated from the airframe and a ground
lead from each jack run back to the radio stack where they will
ground at the intercom (if you have an intercom), the audio panel (if
you have an audio panel without an intercom), or the comm radio (if
you have no intercom or audio panel).
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 23
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Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jun 26, 2006, at 6:37 PM, Carl Morgan wrote:
> --> AeroElectric-List message posted by: "Carl Morgan" <zk-
> vii@rvproject.gen.nz>
>
> All great stuff - I'm going through this at the moment
> (yesterday).....
>
> Questions:
>
> The Panasonic CF2-12V relay
> (http://www.naisweb.com/e/relaye/mech_eng/pdf/mech_eng_cf.pdf) is
> designed
> for car electric windows and provides a nice twin relay (and motor
> breaking - I now note), however DigiKey needs 35 as a minimum
> order.....
> Any other leads for a similar twin option - otherwise it is 4
> singles +
> diodes.....
You don't need fancy relays to have motor control with braking. For
each trim motor you need two single-pole, double-throw (SPDT) relays.
Connect both NC contacts of the relays to ground. Connect both NO
contacts of the relays to +12V. Connect the two leads coming from the
trim motor to the armature (moving) contacts of the two relays, one
wire to each relay. Wire up your trim switches from your yokes/sticks
to energize the relay coils.
When neither relay is energized, both leads of the trim motor are
connected to ground and since they are shorted, the motor will
provide dynamic braking. If you energize one relay the motor will run
in one direction. If you energize the other relay, the motor will run
in the reverse direction. If you inadvertently energize both relays
both leads from the motor get tied to +12 which shorts the motor
leads together and provides braking. This is fail safe in case one
person tries to activate trim in one direction while the other person
tries to activate trim in the other direction. The trim motor doesn't
run in that case. Fail safe.
>
> Speed control: Is it better for a low (regulated) voltage, or 12V
> pulsed
> for a the 'slow' speed? Pro / Cons?
Pulse width control for speed control is better but more expensive to
do.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 24
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Subject: | Re: Glass Panel Layout and |
--> AeroElectric-List message posted by: "Alex Peterson" <alexpeterson@earthlink.net>
> Pilots who *think* they understand computers will trust their
> lives to them, and pilots who truly *do* understand computers
> will not.
Except for those pilots driving cars less than about twenty years old to the
airport, and who may pull out in front of another car, trusting that the
car's computer will keep shoving gas and spark in!
do not archive!
Alex Peterson
RV6-A N66AP 762 hours
Maple Grove, MN
Message 25
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Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 08:13 PM 6/26/2006 +0000, you wrote:
>--> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
>
>Just some very basic information about Ray Allen Servos (or other DC Brush
>Motors) that if you don't know, you should:
>
>The motors used on my T4-5 and whatever model a Europa uses for pitch
>(with indicator) are simple brush motors.
>
>Reverse the polarity of the 2 wires going to the motor, and the motor
>reverses.
This is a permanent magnet motor . . . there are other motors that
also use brushes that have three or perhaps 4-leads and have different
requirements for reversing . . . but the motor you describe is VERY
common.
>If you connect the 2 wires going to the motor to each other, it will act
>as a brake. In other words if the motor is spinning and you disconnect
>power, you are relying on the drag from brushes, gears and load to stop
>the motor. These brush motors are generators if you spin them. They will
>slow up real quick but only if you put a load on them. Connecting the 2
>leads is a good load (generator needs to work with shorted wires, thus
>there is motor braking).
This is called 'dynamic braking' and is recommended for most situations
where motor coast after shut-off is a problem.
>If you draw a schematic of what their reversible switch is doing, things
>will become very clear. Specialized switch (nice job) that you need relays
>to duplicate with mini stick switches.
>
>When I was studying how to deal with switching control from left stick to
>right stick for my 3 servo motors (Aileron Ray Allen, Pitch pay Allen and
>Airmaster Prop) I do see that there are some installs that do not use
>motor braking. I am incorporating Braking.
>
>I went with a multi tier selector switch (will look up info if anyone is
>interested in busting the budget) and 4 relays.
Budget shouldn't be a problem. Relays with mounting feet and push-on
spade terminals from Digi-Key. Goto http://digikey.com
and search on: G8P-1C2T-F-DC12
These are SPDT relays with mounting feet, fast-on terminals,
and cost $4.10 each. They look like this:
http://www.aeroelectric.com/Pictures/Relays/s704inst.jpg
>By using a brake, when you let go of switch there is not much in the way
>of coasting. I think this will be enough control so that I will not need
>to control motor speed.
Controlling motor speed is seldom an issue driven by whether
or not the motor stops quickly . . . optimal trim rates are
linked to indicated airspeed. Aircraft with wide range (greater
than 2:1) difference in IAS for cruise versus over-the-fence
generally benefit from adjustable rates for electrically driven
trim systems.
For the Lears, by the time pitch trim was slowed down sufficiently
for optimum operation at cruise, the pilots had do start trimming
10 miles out to get the machine down to approach speeds over the
fence.
>Another note on controlling speed of a DC brush motor, you can just add
>resistors, which will drop voltage. The motor will not develop as much
>torque.
An un-quantified concern when the neophyte builder hasn't the foggiest
notion of exactly how much torque is needed for a given task . . .
he tries it and if it "works" then he goes on.
> Or you can install a pulse proportion electronic speed controller.
>It will provide full voltage, but depending on selection will limit the on
>time per second, thus slowing down the motor. Also more efficient. If you
>fly model electrics you will appreciate this feature, also there is a lot
>less heat developed in wasted energy (last 2 sentences same thing).
Trim systems are intermittent duty . . . both wattage and total
energy dumped during trim operations is microscopic with compared
with all other requirements for electrical energy. Selecting
a linear versus duty cycle switching versus switch mode regulators
for trim speed control may be an intellectually satisfying exercise
but in the final analysis, I'll suggest that max performance
(accurate, stable set-point), low parts count, low cost of implementation
are high on the list of points to consider irrespective of which
control philosophy is being considered.
>If you don't install a speed controller, it can not fail or make noise.
There are a number of variations on a theme downloadable from . . .
http://www.aeroelectric.com/PPS/Flight/Trim
but in particular . . .
http://www.aeroelectric.com/PPS/Flight/Trim/trim6.pdf
. . . where you see a two-speed trim system that's automatically
set to high speed ops as soon as you extend any flaps. This is
how it was switched on the Lear 35. All the part are available
from Radio Shack or other sources . . .
>Last note while standing on my soap box, do not over drive throw of
>whatever it is you are trying to drive. If you want 3/16 throw up and down
>for roll trim tab, and you are getting 1/2 inch, besides being undesirable
>in event of run away, it is working motor harder than it could, and moves
>far faster than it could, and is more susceptible to stripping gears if
>you have "Muppet's" (as Neville would say) bang into your tab. Increase
>driven control arm, or add a intermediate long arm in, short arm out.
Absolutely! Far to many trim systems have way too much authority
when allowed to drive to mechanical limits described by the kit or
plans. During your fly off, see how much authority is offered by
the as-built system and install mechanical stops or otherwise modify
geometry of the linkage to limit mechanical travel to what's really
needed.
I've know several folks bend airplanes pretty badly (one totaled)
because trim drove to a limit and surprised the pilot when the tail
came up but before he had a lot of aerodynamic authority with controls.
Bob . . .
Message 26
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Subject: | Re: Avionics Stack - Single Point Grounding... |
Electricity flows on all paths inversely proportional to the resistance, i.e. the
lower the resistance, the higher current flow.
Hank
Doug Windhorn <N1DeltaWhiskey@comcast.net> wrote:
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DIV.Section1 { page: Section1 } Disagree, to a point. Positive should
be connected before ground when we are talking about energy sources (say battery).
Why? To prevent a short circuit. If the ground is connected first,
any contact by the positive lead will send sparks
flying. If the positive is connected first, one will be attaching the wire to
a system generally at ground potential.
This goes to the point missing from the comments below. Namely that electrons
move only when invited to do so, either when being sucked by a higher voltage
potential, or when being pushed around by electromagnetic fields (going to stop
there before revealing my ignorance about chemical reactions, but think the
voltage potential is the driving force there). Connecting the ground first
will provide a complete circuit path if the positive terminal is shorted against
the grounded environment generally present in the airframe environment. Connecting
the positive first will only result in a ground coming in contacted with
an intended grounded airframe at the same potential, hence negligible, if
any, sparks will fly.
For energy loads (consumers), it really does not, usually, make much difference
electrically, though it could mechanically (don't have a specific instance,
just leaving the door open to avoid rebuttal on the point). Besides, you have
deenergized the potential circuit before doing this - right?
Doug Windhorn
----- Original Message -----
From: John W. Cox
To: aeroelectric-list@matronics.com
Sent: Monday, 26 June, 2006 8:40
Subject: RE: AeroElectric-List: Avionics Stack - Single Point Grounding...
I am no EE but in A & P school they were quite clear that electrons come from
the negative terminal. That is why the positive is always connected first
and the negative terminal is connected last. The better the negative (Ground)
path Path of least resistance . I know a straight line between two points.
The electrons will always chose the lazy way. Still an important idea for high
quality ground connections.
John Cox - $00.02
---------------------------------
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Fiveonepw@aol.com
Sent: Monday, June 26, 2006 6:40 AM
In a message dated 6/26/06 7:09:07 AM Central Daylight Time, don.honabach@pcperfect.com
writes:
Im trying to wrap my mind around the single-point grounding system as described
in the Connection, in particular as it affects devices in the avionics stack.
>>>>
Some EE out there will undoubtedly correct me, but this is how I look at it:
Electrons come screaming out of the battery up an interstate highway of copper
wire to each device. Once being tortured therein, they must return to the fold
(battery). Given the choice of a return Interstate highway of more copper,
or "over the river & thru the woods (device chassis, screws, metal mashed to other
metal etc.- just think HIGHER RESISTANCE than the highway) they will prefer
the easier route- one that is just as easy going as coming. When all electrons
travel this way, they are happy electrons and are less likely to insidiously
attack your ears as noyz! 8-)
(and yeah, I know about "holes" but let's KIS)
Mark - purty darn quiet Z-11 RV-6A
do not archive unless this adds something to the discussion or I case I'm just
plain wrong!
Message 27
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Subject: | Avionics Stack - Single Point Grounding... |
--> AeroElectric-List message posted by: "Don Honabach" <don.honabach@pcperfect.com>
Thanks everyone - lots of great information!
I understand from the comments I've received that
1. Grounding the 'power grounds' of the avionics to a firewall single-point system
is a good thing.
2. The fact that the avionics have a second power ground available to them via
their cases to the plane's core structure (assuming metal panel/plane) is ok
to leave as is, and putting in a single-point ground system 'on-top' of this 'poorer'
case ground path is preferred.
Onward I go so one day I can go upwards...
Don
-----Original Message-----
Sent: Monday, June 26, 2006 4:20 PM
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
<sigh> This thread is MUCH harder than it needs to be.
The avionics trays should be grounded. If they are in an aluminum
airplane with an aluminum instrument panel and the panel is bolted or
riveted to the airframe somehow, your job is done. If you have some
sort of nonconducting panel such that the avionics trays are
insulated from the rest of the airframe, run a wire from your
avionics tray(s) to your single-point ground.
And this has nothing to do with the power ground for the radios. Each
radio has a ground or multiple ground pins on its connector. These
should be connected to your single point ground independently of the
chassis ground.
Audio grounds, e.g. headphone, mic, audio inputs, etc., should be
isolated and go to a single point ground at the radios. Mic and
headphone jacks should be insulated from the airframe and a ground
lead from each jack run back to the radio stack where they will
ground at the intercom (if you have an intercom), the audio panel (if
you have an audio panel without an intercom), or the comm radio (if
you have no intercom or audio panel).
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupry
Message 28
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Subject: | Re: Ray Allen Trim Servo Wiring |
--> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
Hello Bob
Thx. for chiming in.
Have a few comments****
>>If you draw a schematic of what their reversible switch is doing, things
>>will become clear>>
****Brians post spells out in words and relays exact what ray allen does
with switches. I was hoping some who read my post would sit down and draw
out and figure out this concept. Once concept is grasped, far easier to
exact apply to ones exact application.
>>I went with a multi tier selector switch (will look up info if anyone is
>>interested break the budget. It was more that $125 but lein busting the budget)
and 4 relays.
>
> Budget shouldn't be a problem. Relays with mounting feet and push-on
> spade terminals from Digi-Key. Goto http://digikey.com
> and search on: G8P-1C2T-F-DC12
>
> These are SPDT relays with mounting feet, fast-on terminals,
> and cost $4.10 each. They look like this:
>
> http://www.aeroelectric.com/Pictures/Relays/s704inst.jpg
****The multi tier selector switch I went with can break the budget, it
was more than $125 but less that $150. It is made up of stack-able high
reliability gold contact rated DC switched. Work of art with LEDs to
indicate Pilot or co-Pilot. I am using 2 relays per side ( 2 for pilot and
2 for co pilot "cheap hardware"). I could have gone with a Relay (cheap)
for side selection, but chose to go with the switch. My business is
copiers (since 1975) and have seen relays fail in every inconceivable way.
I trust my chosen selector switch more than a relay. I am relying on this
selector switch in addition to running pitch and roll trim, also prop
motor. If 1 side has a problem, switching to other hopeful will cure till
on the ground.
>>By using a brake, when you let go of switch there is not much in the way
>>of coasting. I think this will be enough control so that I will not need
>>to control motor speed.
>
> Controlling motor speed is seldom an issue driven by whether
> or not the motor stops quickly . . . optimal trim rates are
> linked to indicated airspeed. Aircraft with wide range (greater
> than 2:1) difference in IAS for cruise versus over-the-fence
> generally benefit from adjustable rates for electrically driven
> trim systems.
>
> For the Lears, by the time pitch trim was slowed down sufficiently
> for optimum operation at cruise, the pilots had do start trimming
> 10 miles out to get the machine down to approach speeds over the
> fence.
>
>
>>Another note on controlling speed of a DC brush motor, you can just add
>>resistors, which will drop voltage. The motor will not develop as much
>>torque.
>
> An un-quantified concern when the neophyte builder hasn't the foggiest
> notion of exactly how much torque is needed for a given task . . .
> he tries it and if it "works" then he goes on.
****Your points are well taken. On a fair performance aeroplane like a
Europa, where the Mfg. depicts the servo, and supplies the switch which in
fact incorporates dynamic braking and only full motor speed, if one were
not aware that dynamic braking was designed into the equation, and builder
redesigned without, I suspect that it would be a bit too touchy for ones
taste at cruise. I am sure a pulse with modulation circuit, or a resistor
may help, but braking on a marginal fast system can be the deciding
factor. I have limited time on a europa, but found the pitch trim at
cruise lively and desirable. If it overshot just a bit my input, it may be
undesirable. I fooled with motor with and without braking during build,
braking makes thing awful precise. I will follow kinda sorta your mention
as to how to figure if enough torque is available with a dropping resistor
to slow motor speed "he tries it and if it "works" then he goes on" I will
do the same with Dynamic braking, and if I find that I want slower speed
of motor or 2 speeds, then I will install a speed controller. I would not
second guess the mfg. of a high performance craft that suggests a 2 or
more speed trim at first, if it were me, I would probably build as per
mfg. go fly and modify if I felt it was needed.
>>Last note while standing on my soap box, do not over drive throw of
>>whatever it is you are trying to drive. If you want 3/16 throw up and down
>>for roll trim tab, and you are getting 1/2 inch, besides being undesirable
>>in event of run away, it is working motor harder than it could, and moves
>>far faster than it could, and is more susceptible to stripping gears if
>>you have "Muppet's" (as Neville would say) bang into your tab. Increase
>>driven control arm, or add a intermediate long arm in, short arm out.
>
> Absolutely! Far to many trim systems have way too much authority
> when allowed to drive to mechanical limits described by the kit or
> plans. During your fly off, see how much authority is offered by
> the as-built system and install mechanical stops or otherwise modify
> geometry of the linkage to limit mechanical travel to what's really
> needed.
>
> I've know several folks bend airplanes pretty badly (one totaled)
> because trim drove to a limit and surprised the pilot when the tail
> came up but before he had a lot of aerodynamic authority with controls.
**** Sorry for boring with this now triple mentioned point, but I think it
is important. Will mention benefits as they pertain to models and full
size, perhaps if someone who did not yet get it, this may trigger:
**If you have too much throw, any play in mechanical linkage will equate
to more free play than if you had it set where max. movement of servo was
equal to exact throw needed. Exact throw required equates to more precise
control.
**Too much throw makes trim tab move faster.
**Too much throw provides less force to trim tab and requires motor and
transmission to work harder compared to exact throws.
**Too much throw can grow to way too much throw when the thing runs away
and the internal limit switch fails. I suggest ripping apart servo and
looking at just what is in there, go ahead and scare yourself. As Bob
suggests Mechanical limits or geometry design is prudent. I will make
mention that Europa incorporates a friction damper for the T-Bar that
controls the Anti servo tab for pitch in the event the servo linkage
failed for any number of reasons. The same damper also has mechanical
stops. Without the damper amd a linkage failure, I don't want to be the
one to find out how much damage the subsequent flutter of the antiservo
tabs will do.
Ron Parigoris
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