Today's Message Index:
----------------------
1. 03:59 AM - Re: my other life (KITFOXZ@aol.com)
2. 04:44 AM - Re: my other life (Beckman, Rick)
3. 05:16 AM - Re: my other life (Alex Peterson)
4. 05:29 AM - Mic Jack Wiring (Mark Nielsen)
5. 05:59 AM - Re: Mic Jack Wiring (Rick Caldwell)
6. 06:09 AM - Re: my other life (Robert L. Nuckolls, III)
7. 06:18 AM - Re: my other life (Dennis O'Connor)
8. 06:22 AM - Re: AutoPilot Disconnect (Mark Phillips)
9. 06:27 AM - Re: AutoPilot Disconnect (Mark Phillips)
10. 07:02 AM - Re: AutoPilot Disconnect (Shannon Knoepflein)
11. 07:06 AM - Re: my other life (Robert L. Nuckolls, III)
12. 07:09 AM - Re: AutoPilot Disconnect (Robert L. Nuckolls, III)
13. 07:24 AM - Re: my other life (BobsV35B@aol.com)
14. 07:39 AM - Re: my other life (Robert L. Nuckolls, III)
15. 07:48 AM - Re: Mic Jack Wiring (Robert L. Nuckolls, III)
16. 07:54 AM - Re: Tach P-lead feed (Vincent Welch)
17. 08:37 AM - Re: AutoPilot Disconnect (Robert L. Nuckolls, III)
18. 08:41 AM - Re: OV circuit breaker tripping (Robert L. Nuckolls, III)
19. 09:01 AM - Re: Re: Flap system failure modes (Was circuit protection issues) (Phil Birkelbach)
20. 09:55 AM - Re: AutoPilot Disconnect (Shannon Knoepflein)
21. 10:09 AM - Re: AutoPilot Disconnect Brain Teaser - 05/12/03 (MikeM)
22. 10:32 AM - Re: AutoPilot Disconnect (John Loram)
23. 11:28 AM - Re: Re: AutoPilot Disconnect Brain Teaser - (Robert L. Nuckolls, III)
24. 11:34 AM - Re: AutoPilot Disconnect (Robert L. Nuckolls, III)
25. 11:43 AM - OV runaway in an internally regulated alternator (Robert L. Nuckolls, III)
26. 12:05 PM - Re: OV circuit breaker tripping (JOHN KARNES)
27. 12:06 PM - Re: Re: Flap system failure modes (Was circuit protection issues) (Gilles.Thesee)
28. 12:06 PM - Re: Re: Flap system failure modes (Was circuit protection issues) (Gilles.Thesee)
29. 01:03 PM - Re: Z13 and Dual Electronic Ignitions (Shaun Simpkins)
30. 01:05 PM - Re: OV circuit breaker tripping (Cy Galley)
31. 01:13 PM - Re: Re: AutoPilot Disconnect Brain Teaser - 05/12/03 (Phil Birkelbach)
32. 03:49 PM - Re: Re: AutoPilot Disconnect Brain Teaser -05/12/03 (Robert McCallum)
33. 04:33 PM - Re: Re: Flap system failure modes (Was (Robert L. Nuckolls, III)
34. 04:33 PM - Re: Re: AutoPilot Disconnect Brain Teaser -05/12/03 (Carlos Sa)
35. 05:11 PM - Re: Re: AutoPilot Disconnect Brain Teaser -05/12/03 (Robert McCallum)
36. 05:52 PM - Re: Microprocessor based Fuel Gauge Linearizer (nhulin)
37. 07:48 PM - Re: Re: AutoPilot Disconnect Brain Teaser (Robert L. Nuckolls, III)
38. 07:53 PM - Re: Re: AutoPilot Disconnect Brain Teaser - (Robert L. Nuckolls, III)
39. 07:57 PM - Re: OV circuit breaker tripping (Robert L. Nuckolls, III)
40. 09:15 PM - Re: OV circuit breaker tripping (John Karnes)
41. 09:15 PM - Re: Re: AutoPilot Disconnect Brain Teaser-05/12/03 (Robert McCallum)
42. 09:24 PM - Fw: Electric Bob - Microair Radio-Xpdr Wire Harness (Rick Fogerson)
43. 09:58 PM - Dual electronic ignition - revisited again (Geoff Evans)
44. 10:03 PM - Re: OV circuit breaker tripping (Robert L. Nuckolls, III)
45. 10:04 PM - Re: Fw: Electric Bob - Microair Radio-Xpdr (Robert L. Nuckolls, III)
46. 10:05 PM - Re: Re: AutoPilot Disconnect Brain (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
$200 bucks? Wow Bob. You are definitely earning your keep. Didn't the boss
want a tail rotor on it too? Some of us want you to burn a CD of it dancing
around the yard.
Does it have a name yet? How about the "Rotor Way Reject" J
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 2
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--> AeroElectric-List message posted by: "Beckman, Rick" <Rick.Beckman@ATK.COM>
Thought some of you might be interested in seeing
what I'm doing in the shop for RAC right now. Just
pushed this critter out into the yard for painting
this afternoon.
It's a centrifuge capable of putting 30G of linear
acceleration on some of the equipment we're going
to fly in a new super-sonic target (GQM-163) that
flys mach 2+ at 15 feet off the water.
Good job Bob!!!!!
Message 3
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--> AeroElectric-List message posted by: "Alex Peterson" <alexpeterson@usjet.net>
What happens if that sucker hits a bee or a dragonfly at mach 2???
Alex Peterson
>
> Thought some of you might be interested in seeing
> what I'm doing in the shop for RAC right now. Just
> pushed this critter out into the yard for painting
> this afternoon.
>
> It's a centrifuge capable of putting 30G of linear
> acceleration on some of the equipment we're going
> to fly in a new super-sonic target (GQM-163) that
> flys mach 2+ at 15 feet off the water.
>
>
> http://216.55.140.222/temp/MVC-650X.JPG
> http://216.55.140.222/temp/MVC-651X.JPG
Message 4
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--> AeroElectric-List message posted by: "Mark Nielsen" <mark.nielsen@fiedler-lp.com>
Bob or anyone else,
I have a question on Bob's shop notes on aircraft mic jack wiring (
<http://www.aeroelectric.com/articles/micjack/micjack.html>
http://www.aeroelectric.com/articles/micjack/micjack.html). I am
installing an Icom A200 comm radio. Pin 9 is the PTT switch; the pin is
grounded to activate. The wiring for the Microair that Bob shows appears
to be similar, and the PTT circuit is wired through the PTT terminal on
the mic jack. My question, what happens at the mic jack/plug? Does the
plug just complete the PTT circuit to ground? If so, would it also work
if the jack/plug was taken out of the circuit? (Ground the PTT pin
without wiring the PTT terminal at the jack.)
Or
Is the circuit needed to activate the headset mic? If so, what activates
the mic when you are just using the intercom function?
Mark Nielsen
RV-6; 812 hrs.
Message 5
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| Subject: | Re: Mic Jack Wiring |
--> AeroElectric-List message posted by: "Rick Caldwell" <racaldwell@hotmail.com>
Mark,
This is the "normal" way to wire the PTT. However, you do not need to wire
it to the mic jack. But if you bypass it & go directly to the PTT switch,
you can not use the portable PTT switch that plugs into the mic jack. The
mic itself does not need this wired up.
Rick Caldwell
RV-6 & One Design
>
>I have a question on Bob's shop notes on aircraft mic jack wiring (
><http://www.aeroelectric.com/articles/micjack/micjack.html>
>http://www.aeroelectric.com/articles/micjack/micjack.html). I am
>installing an Icom A200 comm radio. Pin 9 is the PTT switch; the pin is
>grounded to activate. The wiring for the Microair that Bob shows appears
>to be similar, and the PTT circuit is wired through the PTT terminal on
>the mic jack. My question, what happens at the mic jack/plug? Does the
>plug just complete the PTT circuit to ground? If so, would it also work
>if the jack/plug was taken out of the circuit? (Ground the PTT pin
>without wiring the PTT terminal at the jack.)
>
>Or
>
>Is the circuit needed to activate the headset mic? If so, what activates
>the mic when you are just using the intercom function?
>
>Mark Nielsen
>
>RV-6; 812 hrs.
>
>
Message 6
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:10 PM 5/12/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Jaye and Scott Jackson
><jayeandscott@shaw.ca>
>
>What I want to know is where on Earth did you find the time?
>Scott
It's part of my job. The 40 hours I put into it
have been spread out over several months. I also
built a drop tower for shock testing these same
pieces of equipment. By doing these tasks in my
shop at home, I can nudge them along much more
efficiently than if I had them built at RAC. For
one thing, there are no drawings for these pieces
of test equipment. To make a set of drawings from
which someone else would build it might take
40 hours of overhead time just to make the drawings,
get them checked and run through the release system.
Then, if something didn't work out, the person
building the fixture cannot make any changes to
the design until revised drawings are released.
By designing on the fly, I could take advantage
of parts I found in hardware stores and make
instant changes when things didn't come together
as originally envisioned. RAC could have built
it in-house but I suspect they would have invested
about 2x the person-hours. As it stands now, RAC's
total investment is about $3200.
Bob . . .
Message 7
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: "Dennis O'Connor" <doconnor@chartermi.net>
Just a word to the wise, Bob...
Will it work if nothing goes wrong? - Probably... But in my wasted youth I
was around all kinds of machinery and to my eye you need a harness attached
to that upper bearing block with four cables running out to ground anchors,
and the base firmly anchored also... Also, the lower end of the shaft needs
to be longer and set into another bearing or sleeve as the current setup
will twist itself out of the plywood box if the brown stuff hits the
fan...... You can use belt pulleys to run the drill motor from the side of
the shaft... The other thing you need to plan for is containment of a part
flying off... A battery makes a pretty good missile when flung off a 180 rpm
Trebouchet...
The slightest problem, such as the load slipping, a bearing seizing, a
squirrel trying to dive through, etc. will turn that thing into a flail
mower... You just never know with open frame, rotating machinery...
Denny
ya, ya, ya, I know - I'm just an old worry wart...
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: AeroElectric-List: my other life
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> Thought some of you might be interested in seeing
> what I'm doing in the shop for RAC right now. Just
> pushed this critter out into the yard for painting
> this afternoon.
>
> It's a centrifuge capable of putting 30G of linear
> acceleration on some of the equipment we're going
> to fly in a new super-sonic target (GQM-163) that
> flys mach 2+ at 15 feet off the water.
>
>
> http://216.55.140.222/temp/MVC-650X.JPG
> http://216.55.140.222/temp/MVC-651X.JPG
>
> The big bucket holds test articles. The smaller
> bucket holds batteries to power article under
> test. The battery bucket can be moved along the
> beam to coarse balance against the test article.
>
> A table mounts at the center of the beam to
> hold control computer and telemetry to take
> test signals off the centrifuge and control
> signals on.
>
> I used boat trailer 1" wheel bearings I found
> at Walmart. Turned a solid aluminum shaft to
> mount beam, pass through bearings and accept
> rotation torque from 1/2" drill motor underneath.
>
> Drill motor is about 10x oversized for task but
> had nice handles that made it easy to incorporate
> into the test fixture. It looks like something on
> the order of 15 volts DC will spin this rig up to
> about 3 revolutions per second to give me 30G in
> the big bucket.
>
> The boss priced one of these and was quoted about
> $18,000. I think I beat that price by a good margin!
> I've got just over $200 in materials and about
> 40 hours in it.
>
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
>
>
Message 8
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| Subject: | Re: AutoPilot Disconnect |
--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
> http://216.55.140.222/temp/AP_Disconnect_B.pdf
>
> Here's a brain teaser for you electro-wienies out there.
Oh goodie- another chance to publicly expose my ignorance! 8-)
> Why is a diode across the coil of the relay not only
> not needed but would be ineffectual were it included?
Collapsing field current goes to ground through the little switch
> Why, if we can hook an autopilot motor of up to 5A
> on this disconnect system, an itty-bitty stick-grip
> engage/disengage switch good for perhaps 2A is sufficient?
Servo motor current passes through the relay contact, not the relay activate switch
which
only carries relay coil current- which is why we use the things
> Why can we get by with a 1w resistor when dissipation
> in this resistor at 14v is nearly 20 watts?
Coil inductance? Best a bigger wienie than me answer this one! By the way, shouldn't
this
switch be shown as (mom)-off-(mom)?
Mark - do not archive -
Message 9
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| Subject: | Re: AutoPilot Disconnect |
--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
I said: "shouldn't this switch be shown as (mom)off(mom)?"
It is (duh)- that's what the little triangle shaped contacts mean--- too early
to be trying
this stuff! (sorry!)
Mark - do not archive -
Message 10
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Shannon Knoepflein" <kycshann@kyol.net>
The diode will be ineffectual because of the latch in resistor. This
resistor will provide a means of dissipating the coils field current.
Assuming the coil of the s704-1 is about 150 ohms, based on your
statement of less than 100ma to engage, we get 150+10, or 160 ohms
resistance from 14V to ground (once the engage switch is pressed). This
computes to 87.5mA of current flow, hence a 2A switch is more than
enough. The engage current is less than 100mA per the specs of the
s704-1. The disengage current will be 14/10, or 1.4A, still within 2A.
We can get by with the 1W resistor due to the current limiting of the
coil resistance to under 100mA (~150 ohms). Adding the 10ohm resistor
lowers the current further to about 87.5mA. The power dissipated in the
resistor is I
2*R, or 87.5mA
2*10= 0.076W, well under the 1W rating.
---
Shannon Knoepflein <---> kycshann@kyol.net
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: AutoPilot Disconnect
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 01:26 PM 5/12/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
>
>In october last year a link was provided to an autopilot disconnect
>schematic. The link was:
>
>http://216.55.140.222/temp/AP_Disconnect.pdf
>
>The link is dead, does anyone have a copy of the schematic?
>
>Thanks,
>Jim
The old one was replaced with a simpler version
and posted at:
http://216.55.140.222/temp/AP_Disconnect_B.pdf
Here's a brain teaser for you electro-wienies out there.
Why is a diode across the coil of the relay not only
not needed but would be ineffectual were it included?
Why, if we can hook an autopilot motor of up to 5A
on this disconnect system, an itty-bitty stick-grip
engage/disengage switch good for perhaps 2A is sufficient?
Why can we get by with a 1w resistor when dissipation
in this resistor at 14v is nearly 20 watts?
Bob . . .
Message 11
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:58 AM 5/13/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: KITFOXZ@aol.com
>
>$200 bucks? Wow Bob. You are definitely earning your keep. Didn't the boss
>want a tail rotor on it too? Some of us want you to burn a CD of it dancing
>around the yard.
>
>Does it have a name yet? How about the "Rotor Way Reject" J
. . . that's a good one.
Dee's favorite color is purple. I suggested we could
name it the "Rolling Purple Parts Eater". But alas,
I'm almost finished painting it the relatively standard
shop-tool gray.
Bob . . .
Message 12
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:01 PM 5/12/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: John Loram <johnl@loram.org>
>
>This is fun;
>
>The first thing to know is that the relay's coil (S704-1) has a resistance
>of greater than 140 ohms (base on Aeroelectric specs of, "coil current is
>under 100 millamps [sic]").
yes
>In the 'quiescent' state (no servo motor power) there is no current flowing
>through either the coil or the resistor.
yes
>In the 'active' state (servo motor is powered) there is 14 volts to the top
>of the 10 ohm resistor which flows through the resistor and the relay coil
>to ground. This current is sufficient to hold the relay in the active
>position, and is 14volts / (10 ohms + 140 ohms) = .092 amps (92 milliamps).
>This produces .092ma
>2 * 140ohms = 1.18 watts dissipation in the relay (it
>will run warm) and .092ma
>2 * 10 = 0.08 watts dissipation in the resistor.
yes
>During the transition state when the small switch is held in the 'engage'
>position, 14 volts is applied directly across the relay coil, pulling the
>relay into the 'active' state.
yes, but assume you have a 5A load (2.5 ohms) load (servo
motor) what is dissipation in resistor at time of engage switch
closure and how long does it last?
>During the transition state when the small switch is held in the 'disengage'
>position, the junction between the 10 ohm resistor and the relay coil will
>be held at ground. The current (92 milliamps) flowing through the relay coil
>will flow through the small switch to ground, and the energy stored in the
>relay coil's magnetic field will be dissipated in the coil's resistance.
>There will be a brief spike of current (a bit over an amp) from the 10 ohm
>resistor through the small switch. This current will stop as soon as the
>relay's magnetic field falls to the point where the relay contacts open
>(drops out).
Okay, what is the dissipation in resistor at time of
dis-engage switch closure and how long does it last?
What is dissipation mode for energy stored in the
relay coil?
>(is there a prize????) ;-) -john-
Sure, after you finish the test . . .
Bob . . .
Message 13
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 5/13/03 8:19:43 AM Central Daylight Time,
doconnor@chartermi.net writes:
> The slightest problem, such as the load slipping, a bearing seizing, a
> squirrel trying to dive through, etc. will turn that thing into a flail
> mower... You just never know with open frame, rotating machinery...
>
> Denny
>
>
Good Morning Denny,
Or you just put the whole shebang inside a suitable containment vessel, and
let 'er rip!
Happy Skies,
Old Bob
Message 14
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| Subject: | Re: my other life |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:18 AM 5/13/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Dennis O'Connor"
><doconnor@chartermi.net>
>
>Just a word to the wise, Bob...
>Will it work if nothing goes wrong? - Probably... But in my wasted youth I
>was around all kinds of machinery and to my eye you need a harness attached
>to that upper bearing block with four cables running out to ground anchors,
>and the base firmly anchored also... Also, the lower end of the shaft needs
>to be longer and set into another bearing or sleeve as the current setup
>will twist itself out of the plywood box
There are bearings at both ends of the shaft, top and bottom
of the bearing box.
> if the brown stuff hits the
>fan...... You can use belt pulleys to run the drill motor from the side of
>the shaft... The other thing you need to plan for is containment of a part
>flying off... A battery makes a pretty good missile when flung off a 180 rpm
>Trebouchet...
All good points. Keep in mind that for this thing to function
with any degree of civility, it has to be carefully balanced.
We have knife edge balance points at the center of the shaft
flange. Everything on the moving frame has to be held down
with hardware appropriate to the forces. Test articles and
batteries are in the buckets . . . the batteries cannot move
and test articles can't go very far . . . but even these are
fastened in on brackets and hardware good for several times
expected loads. Beam unbalance will be less than 0.1 oz-in.
The beam and buckets are designed for stiffness.
The I-beam is 5 x 5 with 5/16" webs. Friction at the
bearings is quite low. You cannot touch the beam at
the end lightly enough to keep it from rotating
away from you. Acceleration forces will be so low
for both increasing and decreasing speed that the base
can sit in caster-cups.
Buckets are 1/8" alum sheet riveted together with 1/8" angle
at the corners. Force needed to seriously deflect these shapes is
over 4,000 pounds.
>The slightest problem, such as the load slipping, a bearing seizing, a
>squirrel trying to dive through, etc. will turn that thing into a flail
>mower... You just never know with open frame, rotating machinery...
Yup, we've been doing this stuff for years. Just not
on this scale. I had to build this fixture 'cause our
existing rate table will only handle articles up to 2 pounds
or so.
We've studied and learned the need for robustness and
attention to details. Even so, no person will be in
the room with this thing operating. All the computer and
control equipment needed to conduct the operation will
be in zero-G land on a shelf in the center. Command and
monitoring will be done by radio so we can set in the
next room and know what's happening.
Aside from weight (about 80#) and g-forces (#350 lb
max), forces in the rest of the system are very
low.
Bob . . .
Message 15
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| Subject: | Re: Mic Jack Wiring |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:29 AM 5/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Mark Nielsen"
><mark.nielsen@fiedler-lp.com>
>
>Bob or anyone else,
>
>I have a question on Bob's shop notes on aircraft mic jack wiring (
><http://www.aeroelectric.com/articles/micjack/micjack.html>
>http://www.aeroelectric.com/articles/micjack/micjack.html). I am
>installing an Icom A200 comm radio. Pin 9 is the PTT switch; the pin is
>grounded to activate. The wiring for the Microair that Bob shows appears
>to be similar, and the PTT circuit is wired through the PTT terminal on
>the mic jack. My question, what happens at the mic jack/plug? Does the
>plug just complete the PTT circuit to ground?
yes
> If so, would it also work
>if the jack/plug was taken out of the circuit? (Ground the PTT pin
>without wiring the PTT terminal at the jack.)
>
>Or
>
>Is the circuit needed to activate the headset mic? If so, what activates
>the mic when you are just using the intercom function?
no, you can totally remote the ptt wiring. HOWEVER,
it is my personal preference to always wire the mic
jack so that the transmitter will function with
any standard aviation microphone plugged in. I carry
a standard hand mic just in case something comes unhooked
in my headset or other parts of ship's wiring.
Bob . . .
Message 16
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| Subject: | Re: Tach P-lead feed |
--> AeroElectric-List message posted by: "Vincent Welch" <welchvincent@hotmail.com>
I have an EIS4000 and would like to go this route. I called Grand Rapids
and Greg is out for a week and the lady that answered the phone has no idea
what I am talking about. I am using one impulse coupled mag and one
Lightspeed ignition.
Have any of you guys hooked up the EIS with Van's tach transducer, and if
so, would you mind sharing your methods?
Thanks
Vince Welch
>From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>Reply-To: aeroelectric-list@matronics.com
>To: aeroelectric-list@matronics.com
>Subject: Re: AeroElectric-List: Tach P-lead feed
>Date: Mon, 12 May 2003 23:41:16 -0500
>
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
><bob.nuckolls@cox.net>
>
>At 10:32 PM 5/12/2003 -0500, you wrote:
> >--> AeroElectric-List message posted by: Charles Brame
> ><charleyb@earthlink.net>
> >
> >As I understand it, a tach feed from a mag P-lead will work regardless
> >of whether the mag is "On" or "Off." A mag is turned "Off" by grounding
> >it, so the P-lead connection at the mag should continue to provide tach
> >info. The only problem (according to the VM-1000 folks) is that there
> >may be minor erratic tach indications if the mag has an impulse starter.
>
> Don't think so. A mag driven tach looks for the "low"
> voltage mirror image of the spark that appears across OPEN
> points of the mag switch. Closed switch, no spark, no signal
> to tach.
>
>
> >I'm not flying yet, so I cannot confirm. Maybe Bob can confirm.
> >
> >Another option is a transducer that fits on the mechanical tach port on
> >a Lycoming. Van sells the transducer for $60 (part #IE VTACHGEN2) or $67
> >if you have a vacuum pump (part #IE VTACGEN12.)
>
> This is the very best way to go. Bypass the ignition systems
> entirely. I designed tach transducers for the Bonanzas and Barons
> when they went to 2" instruments back in the 80's . . . built
> a hall effect transducer that screwed right onto the tach drive
> fitting of the engine.
>
> Bob . . .
>
>
Message 17
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:00 AM 5/13/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Shannon Knoepflein"
><kycshann@kyol.net>
>
>The diode will be ineffectual because of the latch in resistor. This
>resistor will provide a means of dissipating the coils field current.
that's true if the field collapse current flows through the
resistor . . . but consider that during relay drop-out, there's
a dead short across it through the dis-engage switch.
>Assuming the coil of the s704-1 is about 150 ohms, based on your
>statement of less than 100ma to engage, we get 150+10, or 160 ohms
>resistance from 14V to ground (once the engage switch is pressed). This
>computes to 87.5mA of current flow, hence a 2A switch is more than
>enough. The engage current is less than 100mA per the specs of the
>s704-1. The disengage current will be 14/10, or 1.4A, still within 2A.
>
>
>We can get by with the 1W resistor due to the current limiting of the
>coil resistance to under 100mA (~150 ohms). Adding the 10ohm resistor
>lowers the current further to about 87.5mA. The power dissipated in the
>resistor is I
>2*R, or 87.5mA
>2*10= 0.076W, well under the 1W rating.
Actually, power limiting in the resistor is more a function
of the TIME that major currents flow. During engage, resistor
current flows for the 5 milliseconds of relay pull-in time,
and 2 milliseconds or so of drop-out time during dis-engage.
So actually, a 1/2w resistor would work nicely too.
There's another simple circuit that uses an SCR as the
latching device such that the engage/disengage switch
never sees load current . . . but this circuit needs
more parts too.
I was thumbing through an old notebook and found this
idea recorded from a project I worked on quite some time
ago. It was so much simpler than the diagram I published
last year, I decided to update the published drawing.
By the way, one can make this a multi-pole relay and
run trim motors through their own circuits as well. This
is what would be done on an airplane like a bizjet. One
button disconnects all motors that drive flight surfaces.
Bob . . .
Message 18
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>Bob-
>After disconnecting the ov module and doing the above, the circuit breaker
>stays in for about 8 seconds and then trips. Interestingly, when the
>circuit breaker is in, the voltmeter only reads 12.0 volts. Do you have any
>idea what could be wrong? As I said originally, the alternator is a brand
>new, out of the box, internally regulated 12V variety.
>
>John Karnes
Has this system ever worked for a period of time? I presume
that you're doing this test with the engine running and the
constant indication of 12v suggests that the alternator is
not becoming active at any level. I'd check over the wiring.
Try closing the alternator control switch with the engine not
running. You should hear the alternator disconnect contactor
operate and the breaker should stay in.
Sounds like a possible wiring problem.
Bob . . .
Message 19
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| Subject: | Re: Flap system failure modes (Was circuit protection |
issues)
--> AeroElectric-List message posted by: "Phil Birkelbach" <phil@petrasoft.net>
> Giles sent me the following photo:
> http://216.55.140.222/temp/flap_drive.jpg
>
> Let's fully explore whether or not you really
> want to put this system into your airplane. Then
> let's see if there are some simpler yet practical
> approaches to keeping working motors powered and
> smoke inside the wires.
>
> I'm convinced that we're just spinning our
> wheels on the electrical side until we have
> some confidence on how the mechanical side is
> going to work and how it behaves when it's
> not working.
>
I have to agree with Bob. I think that I would SERIOUSLY explore the
reasons why there are four motors in this system. It will NOT increase the
reliability of this system. Especially with the worm gears. I suspect that
those worm gears have a fairly high turn down and the higher the turn down
on a worm gear the higher the braking action. Try to get one set of these
motors to turn with only one motor wired up. If they won't do it then I'd
send the whole thing back to whomever built it and design/buy a system that
uses one motor.
There may be a ratchet type clutch in there somewhere that would allow for
the flaps to at least be retracted once if something broke but then you
would not be able to extend them. Depending on the airplane this may be
acceptable.
Get us some more information about this system and what problems were
associated with the design of the system. Did they need more torque? Is
there a space constraint? Did they assume that more motors would be more
reliable? Sometimes in a design of a system like this there are problems
that surface that initiate a solution that unknowingly creates other
problems. It happens to me at work all the time, I get started down a path
to solve one little problem and it is hard to disassociate myself from that
small problem so I don't see the bigger problem that my solution created
until later. This is where a second, third, or fourth set of eyes can
really help.
Godspeed,
Phil Birkelbach
RV7 - 727WB (Reserved)
http://www.myrv7.com
Message 20
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Shannon Knoepflein" <kycshann@kyol.net>
Dissipation in resistor at time of disengage is (14-0)/10, or 1.4A, or
19.6W. It lasts about 2ms from your post. However, there is a way to
calculate it based on the R and L values.
There is some time constant. For an RC circuit, its 1/RC. If I recall
correctly, for an RL, it would be L/R. Close? If that's correct, does
the coil have an inductance of about 0.32H, assuming R is 150 + 10=160?
---
Shannon Knoepflein <---> kycshann@kyol.net
Okay, what is the dissipation in resistor at time of
dis-engage switch closure and how long does it last?
What is dissipation mode for energy stored in the
relay coil?
>(is there a prize????) ;-) -john-
Sure, after you finish the test . . .
Bob . . .
Message 21
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - 05/12/03 |
--> AeroElectric-List message posted by: MikeM <mladejov@ced.utah.edu>
With reference to:
> http://216.55.140.222/temp/AP_Disconnect_B.pdf
>
> Here's a brain teaser for you electro-wienies out there.
Oh Goody, a pop quiz like the ones I spring on my students!
> Why is a diode across the coil of the relay not only
> not needed but would be ineffectual were it included?
A snubber diode is not required because as the switch is moved
to the "disengage" position, it is shorting the relay coil, and
thereby provides a path for the coil current to continue flowing
while the energy stored in the magnetic field is dissipated in
the coil resistance. The closed switch contact effectively
holds the coil voltage at 0 V, so absent a forward bias, a diode
would do nothing!
> Why, if we can hook an autopilot motor of up to 5A
> on this disconnect system, an itty-bitty stick-grip
> engage/disengage switch good for perhaps 2A is sufficient?
While the switch is held in the "engage" position, the relay
coil resistance limits the current through the switch to
E/R=14/120=0.12A. On "disengage", the peak current is
E/R=14/10=1.4A, but lasts only while the relay magnetic field
collapses and the relay contacts release. If an external current
path is provided (in this case through the switch), a relay like
this typically releases in about 10msec.
> Why can we get by with a 1w resistor when dissipation
> in this resistor at 14v is nearly 20 watts?
Even though the peak instantaneous dissipation in the resistor
is E
2/R=14*14/10=19.6W, the event lasts only for ~10 msec. A 1W
resistor will take 20W for 10msec provided it only happens
occasionally. I'm guessing that a 1/4 or 1/2 W resistor would be
sufficient.
Proff. Mike Mladejovsky, PhDEE (penultimate electro wienie)
Skylane '1MM
Pacer '00Z
Message 22
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: John Loram <johnl@loram.org>
At 10:01 PM 5/12/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: John Loram <johnl@loram.org>
>
>This is fun;
>
>The first thing to know is that the relay's coil (S704-1) has a resistance
>of greater than 140 ohms (base on Aeroelectric specs of, "coil current is
>under 100 millamps [sic]").
yes
>In the 'quiescent' state (no servo motor power) there is no current flowing
>through either the coil or the resistor.
yes
>In the 'active' state (servo motor is powered) there is 14 volts to the top
>of the 10 ohm resistor which flows through the resistor and the relay coil
>to ground. This current is sufficient to hold the relay in the active
>position, and is 14volts / (10 ohms + 140 ohms) = .092 amps (92 milliamps).
>This produces .092ma
>2 * 140ohms = 1.18 watts dissipation in the relay (it
>will run warm) and .092ma
>2 * 10 = 0.08 watts dissipation in the resistor.
yes
>During the transition state when the small switch is held in the 'engage'
>position, 14 volts is applied directly across the relay coil, pulling the
>relay into the 'active' state.
yes, but assume you have a 5A load (2.5 ohms) load (servo
motor) what is dissipation in resistor at time of engage switch
closure and how long does it last?
Yeh, I should have said something about that. At the time I didn't know
anything about the servo motor's electrical characteristics so left the
answer incomplete;
There will be a current surge through the resistor and small switch of
14volts/(1/(1/10+1/2.5)) = 2amps (plus 100 milliamps through the relay coil
or 1.4 watts in the resistor. It will last unit the relay pulls into the
active state (a few milliseconds at worst) at which time the current through
the small switch will drop to 100 milliamps (coil current) until the small
switch is opened.
>During the transition state when the small switch is held in the
'disengage'
>position, the junction between the 10 ohm resistor and the relay coil will
>be held at ground. The current (92 milliamps) flowing through the relay
coil
>will flow through the small switch to ground, and the energy stored in the
>relay coil's magnetic field will be dissipated in the coil's resistance.
>There will be a brief spike of current (a bit over an amp) from the 10 ohm
>resistor through the small switch. This current will stop as soon as the
>relay's magnetic field falls to the point where the relay contacts open
>(drops out).
Okay, what is the dissipation in resistor at time of
dis-engage switch closure and how long does it last?
There will be a brief surge of current through the switch at disengage time
which will be the sum of the current through the resistor (14 volts / 10
ohms = 1.4 amps (19.6watts )(I'm assuming for simplicity that the servo
motor is purely resistive) and the coil current .092 milliamps. The current
through the resistor will continue until the magnetic field in the relay
collapses to the point at which the relay drops out (usually several
milliseconds).
What is dissipation mode for energy stored in the
relay coil?
The energy stored in the relay coil's magnetic field will be dissipated in
the coil's resistance as the current circulates, primarily through the small
switch.
This analysis makes some simplifying assumptions; most importantly that the
switch and relay contacts have zero resistance, and that the only non-purely
resistive component is the relay coil. The calculation of the effect of
these tertiary elements are left to the student.... ;-)
>(is there a prize????) ;-) -john-
Sure, after you finish the test . . .
Bob . . .
Message 23
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
05/12/03
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:06 AM 5/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: MikeM <mladejov@ced.utah.edu>
>
>With reference to:
>
> > http://216.55.140.222/temp/AP_Disconnect_B.pdf
> >
> > Here's a brain teaser for you electro-wienies out there.
>
>Oh Goody, a pop quiz like the ones I spring on my students!
>
<snip>
>Even though the peak instantaneous dissipation in the resistor
>is E
>2/R=14*14/10=19.6W, the event lasts only for ~10 msec. A 1W
>resistor will take 20W for 10msec provided it only happens
>occasionally. I'm guessing that a 1/4 or 1/2 W resistor would be
>sufficient.
>
>Proff. Mike Mladejovsky, PhDEE (penultimate electro wienie)
>Skylane '1MM
>Pacer '00Z
You got it.
If you like good illustrative brain teasers, try these
on the class . . .
Take molecules of water in 1 cc and enlarge to size
of ping-pong ball (assume 1.5" diameter). Spread
them uniformly over surface of contiguous US
(assume) 5.7 x 10
6 square miles. To what depth
will the ping-pong balls cover the United States?
Another eye-opener . . .
Take an array of steel balls 0.001" in diameter
and stack them into 1 cubic inch of volume. How
many balls does it take to fill the cube? What
is the total surface area of all balls contained
in the cube? What is the open (see-through) area
of the space between the balls for any liquid
that passes into one face and out the opposite face?
Bob . . .
Message 24
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:52 PM 5/13/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Shannon Knoepflein"
><kycshann@kyol.net>
>
>Dissipation in resistor at time of disengage is (14-0)/10, or 1.4A, or
>19.6W. It lasts about 2ms from your post. However, there is a way to
>calculate it based on the R and L values.
>
>There is some time constant. For an RC circuit, its 1/RC. If I recall
>correctly, for an RL, it would be L/R. Close? If that's correct, does
>the coil have an inductance of about 0.32H, assuming R is 150 + 10=160?
You're correct that there are other relationships to consider
but in comparison to the major effects, they are pretty small
and I was neglecting them. The major effects for what the
resistor sees have more to do with Bus, Load and engage/disengage
switch. For example, you could substitute a 160 ohm resistor for
the effects of the relay coil and not significantly
change the outcome of the analysis.
Bob . . .
Message 25
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| Subject: | OV runaway in an internally regulated alternator |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:01 PM 5/13/2003 +0000, you wrote:
>Below is the result of your inquiry. It was submitted by
>Frank Piszkin (fpiszkin@thegrid.net) on Tuesday, May 13, 2003 at 11:01:57
>
>Tuesday, May 13, 2003
>
>Frank Piszkin
>
>,
>Email: fpiszkin@thegrid.net
>Comments/Questions: I submitted this inquiry a couple of weeks ago but
>have received no response.
>So, again, can you help me understand how the alternator disconnect contactor
>(S701-1) effects a disconnect? My electrical knowledge is barely beyond Ohm's
>Law. Looking at the wiring diagram you provided (for the internal regulator),
>it appears to me that the OVM-14 module is required to drop out the field
>voltage
>to the alternator (and the contactor) and cause the contactor to disconnect.
>But there is a jumper wire on the contactor which would appear to hold in
>the contactor since it provides a path to the battery side. What am I
>misunderstanding?
>And, why is the disconnect contactor required if the OVM-14 would, by itself,
>remove the field voltage from the alternator? Is it just simply to assure
>isolation
>of the aternator from the battery side? Please dumb it down for me, Bob. I
>really do
>want to understand how the system functions before I go wiring things up.
>Thanks, Frank
I think I invited you to join the AeroElectric List
for this conversation. I get lots of requests for one-on-one
tutorials every week and I've got a limited amount
of time to devote to operating the 'Connection. When
you put these questions out on the list, you're more
likely to get a response from me because (1) I've blocked out
most of my time to support the list and (2) the information
is shared with lots of other folks. Moreover, there are
many folks on the list besides me who can do a good job
of answering.
Not trying to be a hard-ass. Further, I very much appreciate
and encourage your desire to understand how the system
works. I firmly belive in the dissemination of knowledge.
But this activity works 1000% better in a forum where
many can benefit both as students and as teachers.
In a nutshell . . . internally regulated alternators
do not get their field excitation current from the
control lead. There are failure modes within an internally
regulated alternator that cannot be overridden by
shutting off the control lead. Hence, the need for
physical and total disconnection of the alternator
from ship's wiring in the event of an overvoltage
event.
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
Message 26
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "JOHN KARNES" <jpkarnes@charter.net>
> Has this system ever worked for a period of time? I
>presume
> that you're doing this test with the engine running
>and the
> constant indication of 12v suggests that the
>alternator is
> not becoming active at any level. I'd check over the
>wiring.
> Try closing the alternator control switch with the
>engine not
> running. You should hear the alternator disconnect
>contactor
> operate and the breaker should stay in.
>
> Sounds like a possible wiring problem.
>
> Bob . . .
Bob-
The system worked fine as currently wired until my engine
overheated last summer. The old alternator had bad
diodes, so I thought that was the problem. After
replacing the OV module and alternator, the problem
continues. Why would the circuit breaker trip if there is
only 12V leaving the alternator? When the button is
pushed in on the circuit breaker, there is a small rise in
voltage, albeit only to 12.0 V. If there is a wiring
problem, where would you suggest I look? Thanks for your
help
John Karnes
jpkarnes@charter.net
Message 27
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| Subject: | Re: Flap system failure modes (Was circuit protection |
issues)
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
Hi Bob and all,
> It sounds to me like your airplane has flaps capable of
> defining a high-risk envelope that you want to avoid by
> NOT extending flaps beyond a value that you can arrest
> decent until your comfortable landing is assured. This
> has nothing to do with flap extension/retraction reliability.
> Suggest you fully explore this with someone very familiar
> with your airplane or experienced enough as a test pilot
> to help you put bounds on operating conditions.
>
This has been recognized by the kit manufacturer, who proposes to reduce
flap extension to less drastic values. By the way the test pilot is my
former chief pilot and aerobatics coach.
>
> I think I disagree. Looking at the picture you sent I
> perceive that the motors drive a common shaft though worm
> gear drives. Worm gears are horribly inefficient . . . usually
> 50% or less. They can produce tremendous mechanical
> advantage in one gear-pass . . . that's why they are popular.
> Their ability to resist back driving due to horrible efficiency
> is sometimes RELIED upon . . .
>
....................
>
> I presume that four motors were put into this system because
> someone perceived that this much horsepower was needed -OR-
> they thought that even if only two motors were needed to
> run the flaps, dual motors would give some degree of reliability
> enhancement.
>
> I am skeptical that this 4-motor system would still be okay
> with one motor inoperative but mechanically free. If one motor
> throws a comm bar or winding and locks up, then the system
> is definitely in trouble.
>
................
>
> I'm convinced that we're just spinning our
> wheels on the electrical side until we have
> some confidence on how the mechanical side is
> going to work and how it behaves when it's
> not working.
Please tell me if I understand correctly : the flap system could very well
lock up in case of motor failure. Provided I have to wire the system as is,
I have to make provision for an electrically safe behaviour in this case.
The resettable breaker is out of the question, any resetting could induce
wire overheating, or asymetrical deployment.
> Has this system flown?
The system is flying in about 40 to 50 two seaters and five or so four
seaters. The only failures I'm aware of are smoke under the panel on the
ground, and failure to extend due to loose connections.
Has it been tested for all
> failure modes including passive failure of one motor
> and hard failure (locked armature) of one motor?
>
I guess you and I know too well....
>
> That bar on the floor for manual flap operation is pretty
> hard to beat too. My recommendations for wiring and
> protection may indeed keep your wires from catching fire
> . . . but given the questions I've cited above, your
> biggest concerns may have nothing to do with keeping the
> smoke in your wires.
You're right.
Hand flaps are among the safest. But such a system would entail extensive
mods of the fuselage, console and throttle, wire conduits etc...
Unfortunately the decisions have been made last year, and I'm not in a
position to decide on a major redesign of the mechanical systems. I'm only
in charge of the wiring, but I'm determined to accomplish it as best as I
can, and thanks to your advice, to make it as ELECTRICALLY safe as is
practically possible.
That's why I was thinking of a fuselink to replace the fast acting fuse.
Doable, not doable ?
>
> I forget now, which airplane are you building?
It is an MCR 4S, see
http://www.avnet.co.uk/touchdown/pages/mcr4s.htm
Thanks for all your help.
Message 28
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| Subject: | Re: Flap system failure modes (Was circuit protection |
issues)
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
Phil,
>
> I have to agree with Bob. I think that I would SERIOUSLY explore the
> reasons why there are four motors in this system. It will NOT increase
the
> reliability of this system. Especially with the worm gears. I suspect
that
> those worm gears have a fairly high turn down and the higher the turn down
> on a worm gear the higher the braking action. Try to get one set of these
> motors to turn with only one motor wired up. If they won't do it then I'd
> send the whole thing back to whomever built it and design/buy a system
that
> uses one motor.
If it were my airplane, I would'nt even bother to make this experiment : I'd
design something else from the start. But I'm NOT the one who makes the
decisions on that project.
I definitely am the one in charge of making those motors spin as long as
they don't fall apart or weld solid inside, and keeping the smoke inside the
wires.
>
> There may be a ratchet type clutch in there somewhere that would allow for
> the flaps to at least be retracted once if something broke but then you
> would not be able to extend them. Depending on the airplane this may be
> acceptable.
>
> Get us some more information about this system and what problems were
> associated with the design of the system. Did they need more torque?
Sure
Is
> there a space constraint?
No
Did they assume that more motors would be more
> reliable?
Don't think so. Torque. And being acqainted with the motor for already using
it for the pitch trim.
Sometimes in a design of a system like this there are problems
> that surface that initiate a solution that unknowingly creates other
> problems. It happens to me at work all the time, I get started down a
path
> to solve one little problem and it is hard to disassociate myself from
that
> small problem so I don't see the bigger problem that my solution created
> until later. This is where a second, third, or fourth set of eyes can
> really help.
>
See my other mail. thanks for your advice,
Gilles
Message 29
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| Subject: | Re: Z13 and Dual Electronic Ignitions |
--> AeroElectric-List message posted by: "Shaun Simpkins" <shauns@hevanet.com>
>. . . hmmm . . . maybe that's IT!
> [Cirrus] may be selling airplanes with flooded batteries
>that cost a lot and they assume the owner is going to
> leave it in place for a long time .
>Bob . . .
Bob:
Thanks.
I think that's the reason. The prime battery is up front, the secondary
battery is buried behind the rear seat, where the owner will forget about
it until it's too late. The diode connection from the primary to the secondary
alternator system suggests that Cirrus expects the secondary battery to be
forgotten; if it dies, they're counting on the primary system to take over. Which
says
their e-bus is really the primary system, and...ecch.
Shaun
Message 30
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Cy Galley" <cgalley@qcbc.org>
Sounds like a dead short.
It would pull down the voltage and the excess amperage would trip the
breaker.
Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh
Editor, EAA Safety Programs
cgalley@qcbc.org or experimenter@eaa.org
Always looking for articles for the Experimenter
----- Original Message -----
From: "JOHN KARNES" <jpkarnes@charter.net>
Subject: Re: AeroElectric-List: OV circuit breaker tripping
> --> AeroElectric-List message posted by: "JOHN KARNES"
<jpkarnes@charter.net>
>
> > Has this system ever worked for a period of time? I
> >presume
> > that you're doing this test with the engine running
> >and the
> > constant indication of 12v suggests that the
> >alternator is
> > not becoming active at any level. I'd check over the
> >wiring.
> > Try closing the alternator control switch with the
> >engine not
> > running. You should hear the alternator disconnect
> >contactor
> > operate and the breaker should stay in.
> >
> > Sounds like a possible wiring problem.
> >
> > Bob . . .
>
>
> Bob-
> The system worked fine as currently wired until my engine
> overheated last summer. The old alternator had bad
> diodes, so I thought that was the problem. After
> replacing the OV module and alternator, the problem
> continues. Why would the circuit breaker trip if there is
> only 12V leaving the alternator? When the button is
> pushed in on the circuit breaker, there is a small rise in
> voltage, albeit only to 12.0 V. If there is a wiring
> problem, where would you suggest I look? Thanks for your
> help
>
> John Karnes
> jpkarnes@charter.net
>
>
Message 31
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - 05/12/03 |
--> AeroElectric-List message posted by: "Phil Birkelbach" <phil@petrasoft.net>
> Take an array of steel balls 0.001" in diameter
> and stack them into 1 cubic inch of volume. How
> many balls does it take to fill the cube? What
> is the total surface area of all balls contained
> in the cube? What is the open (see-through) area
> of the space between the balls for any liquid
> that passes into one face and out the opposite face?
>
> Bob . . .
>
You'll need 1,000
3 steel balls or...
1,000,000,000 balls
The surface area of a sphere is... 4*pi*r
2
So the area of one ball... 3.141592E-6 sq in
So the area of a billion balls... 3,141.5 sq in or 21.8166 sq ft
which is about 2/3 the area of a piece of plywood.
Now for the second part the wetted area...
It would be 1 sq in - the area of a million circles...
area of a circle = pi * r
2
Area of a 0.001" diameter circle = 7.85398E-7 sq in
Area of a million of them would be... 0.785398 sq in
so the see through area would be... 0.214602 sq in
Of course this all assumes that we stack the balls in a rectangular pattern
1,000 balls to an edge, and the 1 cubic inch volume is a 1" x 1" x 1" cube,
if it is anything more sinister than that then I don't have time to look it
up. :-)
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Fuselage
http://www.myrv7.com
Message 32
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| Subject: | Re: AutoPilot Disconnect Brain Teaser -05/12/03 |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
"Robert L. Nuckolls, III" wrote:
> -->
>
> Another eye-opener . . .
>
> Take an array of steel balls 0.001" in diameter
> and stack them into 1 cubic inch of volume. How
> many balls does it take to fill the cube? What
> is the total surface area of all balls contained
> in the cube? What is the open (see-through) area
> of the space between the balls for any liquid
> that passes into one face and out the opposite face?
>
> Bob . . .
>
1,000,000,000 balls (1 billion)
2,000,000 square inches (.318845 acres)
.21461 square inches of open area (just shy of 1/4 of the total area)
--
Bob McC
DO NOT ARCHIVE
Message 33
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| Subject: | Re: Flap system failure modes (Was |
circuit protection issues)
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:48 PM 5/13/2003 +0200, you wrote:
>--> AeroElectric-List message posted by: "Gilles.Thesee"
><Gilles.Thesee@ac-grenoble.fr>
>
>
>Hi Bob and all,
>
>
> > It sounds to me like your airplane has flaps capable of
> > defining a high-risk envelope that you want to avoid by
> > NOT extending flaps beyond a value that you can arrest
> > decent until your comfortable landing is assured. This
> > has nothing to do with flap extension/retraction reliability.
> > Suggest you fully explore this with someone very familiar
> > with your airplane or experienced enough as a test pilot
> > to help you put bounds on operating conditions.
> >
>
>This has been recognized by the kit manufacturer, who proposes to reduce
>flap extension to less drastic values. By the way the test pilot is my
>former chief pilot and aerobatics coach.
Okay. I'm not sure you need to have an on-purpose limitation
to the flaps as long as your pilots are aware how to use
them safely. Benefits of flaps happen at touchdown. More
flaps just makes you come down faster and leaves you with
less energy to squander in the flare. If I were a flight
instructor, I'd not let a student use flaps at all until
they were proficient without them.
In the older C-150's, you could get the best of both
worlds by hanging out no more drag than you can tolerate
at full throttle to arrest your descent. When you're
sure you have the landing made, put out the rest of
the flaps.
>Please tell me if I understand correctly : the flap system could very well
>lock up in case of motor failure. Provided I have to wire the system as is,
>I have to make provision for an electrically safe behaviour in this case.
>The resettable breaker is out of the question, any resetting could induce
>wire overheating, or asymetrical deployment.
This is a distinct possibility.
> > Has this system flown?
>
>The system is flying in about 40 to 50 two seaters and five or so four
>seaters. The only failures I'm aware of are smoke under the panel on the
>ground, and failure to extend due to loose connections.
>
> > Has it been tested for all
> > failure modes including passive failure of one motor
> > and hard failure (locked armature) of one motor?
> >
>
>I guess you and I know too well....
Okay, let's see what we can do to make failures as tolerant
as possible. I think I'd simply wire all four motors in
parallel with each other. Treat them as a single motor.
Drive the system through a single, 20A breaker at the bus.
The idea of protecting each motor in any way is scary. You
don't want the system to continue to run in any way if one
motor has decided to mis-behave.
My sense is that this little airplane simply cannot need
as much snort as a 20A breaker would suggest. Wire with
14AWG wire and put a 20A breaker in for now. During flight
testing, let's put an ammeter in and see what the system
REALLY needs. I wouldn't be surprised to see that we can
drop the breaker size down to 15 or even 10 amps. An
RV actuator runs at under 5A. You don't need to size the
breaker for inrush currents.
If one wanted to reduce the hazards of single motor
failure, we could design some fancy circuitry to sense
abnormal operation and shut the whole system down
when it was detected.
Single point protection combined with judicious use
of flaps in approach-to-landing should let you make the
best of a rather un-thoughtful design. This wouldn't be
the only airplane flying around with idiosyncrasies
capable of embarrassing you or driving your pucker
factor up. Take a checkout in a Tri-Pacer or a AA-1
Yankee and have the check pilot show you how easy it
is to get tense in these airplanes. They ain't your
grandfather's C-172.
If this system has a satisfactory history . . . meaning
that gear-boxes aren't shelling out and motors are
hanging in there, then you're not facing gross design
limits or high rates of infant mortality. This suggests
that until a motor or gearbox reaches wear-out,
you won't have to shoulder duties as a failure modes
test-pilot soon. Maybe this won't happen until after you've
sold the airplane.
Bob . . .
Message 34
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| Subject: | Re: AutoPilot Disconnect Brain Teaser -05/12/03 |
--> AeroElectric-List message posted by: Carlos Sa <carlosfsa@yahoo.com>
> > Another eye-opener . . .
> >
> > Take an array of steel balls 0.001" in diameter
> > and stack them into 1 cubic inch of volume. How
> > many balls does it take to fill the cube? What
> > is the total surface area of all balls contained
> > in the cube? What is the open (see-through) area
> > of the space between the balls for any liquid
> > that passes into one face and out the opposite face?
> >
> > Bob . . .
> >
>
> 1,000,000,000 balls (1 billion)
> 2,000,000 square inches (.318845 acres)
> .21461 square inches of open area (just shy of 1/4 of the total area)
>
> --
> Bob McC
> DO NOT ARCHIVE
Bob, how didja do that? I gave up stacking them at 521,381,234??? :o)
Sorry, couldn't resist...
Message 35
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| Subject: | Re: AutoPilot Disconnect Brain Teaser -05/12/03 |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
Carlos Sa wrote:
>
> Bob, how didja do that? I gave up stacking them at 521,381,234??? :o)
>
> Sorry, couldn't resist...
>
Had my assistant (wife) do the second half.
--
Bob McC
DO NOT ARCHIVE
Message 36
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| Subject: | Re: Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: "nhulin" <nhulin@hotmail.com>
On Mon May 12 at 7:31 PM Jim Ziegler (jcz@espllc.com) wrote:
> I might be interested, do you have a summary of the requirements?
Guys,
Are you trying to solve a problem here that has limitations that you are
unlikely to overcome?
I've just installed the fuel tanks in my Zodiac 601XL and have been testing
the installation of the VDO style float arm resistive senders. The Zodiac
uses tanks of uniform shape but they are installed in a wing with dihedral.
Given that the sender is installed in the lower end of the tank to give the
best empty reading, the size of the float ball, and the dihedral, I found
that for the first few gallons down from full the float ball is pinned to
the top of the tank and no meaningful reading can be expected (except, of
course, "full"). On the low end it is much better but the ball eventually
bottoms before the tank is empty. In the middle it is reasonably linear.
For a very unusually shaped tank the linearizer would be helpful. The cost?
Perhaps a fuel totalizer would provide more benefit in these cases.
Just my 2c.
BTW: I designed a simple LED bargraph fuel gauge that seems to work OK (at
least in prototype form) since I have four tanks and the cost of gauges was
a bit too much. If I'm happy with the design when it is finished I'll let
the Aero'List know.
...neil
Neil Hulin
Zodiac 601XL
Cincinnati Ohio
Message 37
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| Subject: | Re: AutoPilot Disconnect Brain Teaser |
-05/12/03
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:45 PM 5/13/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: Robert McCallum
><robert.mccallum2@sympatico.ca>
>
>"Robert L. Nuckolls, III" wrote:
>
> > -->
> >
> > Another eye-opener . . .
> >
> > Take an array of steel balls 0.001" in diameter
> > and stack them into 1 cubic inch of volume. How
> > many balls does it take to fill the cube? What
> > is the total surface area of all balls contained
> > in the cube? What is the open (see-through) area
> > of the space between the balls for any liquid
> > that passes into one face and out the opposite face?
> >
> > Bob . . .
> >
>
>1,000,000,000 balls (1 billion)
yes
>2,000,000 square inches (.318845 acres)
??????
>.21461 square inches of open area (just shy of 1/4 of the total area)
yes
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 38
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
05/12/03
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:10 PM 5/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Phil Birkelbach"
><phil@petrasoft.net>
>
> > Take an array of steel balls 0.001" in diameter
> > and stack them into 1 cubic inch of volume. How
> > many balls does it take to fill the cube? What
> > is the total surface area of all balls contained
> > in the cube? What is the open (see-through) area
> > of the space between the balls for any liquid
> > that passes into one face and out the opposite face?
> >
> > Bob . . .
> >
>You'll need 1,000
3 steel balls or...
>
>1,000,000,000 balls
>
>The surface area of a sphere is... 4*pi*r
2
>
>So the area of one ball... 3.141592E-6 sq in
>So the area of a billion balls... 3,141.5 sq in or 21.8166 sq ft
>which is about 2/3 the area of a piece of plywood.
That's the part that really surprises folks . . . that
a 1" cube could have that much surface area contained
within.
>Now for the second part the wetted area...
>
>It would be 1 sq in - the area of a million circles...
>
>area of a circle = pi * r
2
>
>Area of a 0.001" diameter circle = 7.85398E-7 sq in
>Area of a million of them would be... 0.785398 sq in
>so the see through area would be... 0.214602 sq in
yup . . .
>Of course this all assumes that we stack the balls in a rectangular pattern
>1,000 balls to an edge, and the 1 cubic inch volume is a 1" x 1" x 1" cube,
>if it is anything more sinister than that then I don't have time to look it
>up. :-)
yeah, getting all those balls to set in there un-nested
takes some REAL patience.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 39
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:03 PM 5/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Cy Galley" <cgalley@qcbc.org>
>
>Sounds like a dead short.
>It would pull down the voltage and the excess amperage would trip the
>breaker.
I agree . . . check to make sure your diode on
the b-lead contactor isn't hooked up backwards
or shorted.
>Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh
>
>Editor, EAA Safety Programs
>cgalley@qcbc.org or experimenter@eaa.org
>
>Always looking for articles for the Experimenter
Cy, Have you picked through the stuff on downloadables
section of aeroelectric.com? If there's something you
like there, let me know . . . it might need updating.
Bob . . .
Message 40
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "John Karnes" <jpkarnes@charter.net>
> >Sounds like a dead short.
> >It would pull down the voltage and the excess amperage would trip the
> >breaker.
>
> I agree . . . check to make sure your diode on
> the b-lead contactor isn't hooked up backwards
> or shorted.
How do I check to see if the diode is shorted? I know it's not backwards as
I haven't changed it and it was working fine before. Could the high heat in
the engine compartment have caused this? (I'm talking HIGH heat!)
John Karnes
Message 41
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| Subject: | Re: AutoPilot Disconnect Brain Teaser-05/12/03 |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
"Robert L. Nuckolls, III" wrote:
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>
> >2,000,000 square inches (.318845 acres)
>
> ??????
This would be the answer when you are trying to demonstrate your stupidity by leaving
out half the
formula in the rush to get to the dinner table after being called three times,
then not even
bothering with a reasonability check before pushing the send button. (feeling a
little silly)
--
Bob McC
DO NOT ARCHIVE
Message 42
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| Subject: | Fw: Electric Bob - Microair Radio-Xpdr Wire Harness |
--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
----- Original Message -----
From: Rick Fogerson
Subject: Microair Radio-Xpdr Wire Harness
Hi Bob,
Are you going to be selling wiring harness's for the Microair radio or xpdr anytime
soon?
Rick Fogerson
Message 43
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| Subject: | Dual electronic ignition - revisited again |
--> AeroElectric-List message posted by: Geoff Evans <hellothaimassage@yahoo.com>
Hi Bob.
I thought I was all squared away after our message exchange of a few months
ago, but some recent postings of yours on the list have rekindled my
confusion.
Our prior conversations were about using the Z-13 architecture for dual
electronic ignitions, and whether the Z-13 system was any more likely to
result in an electrically-caused engine failure (with dual electronic
ignitions) than a something like a Z-11 system with an aux battery. At the
time, I was confused by some prior postings and some seemingly conflicting
language in your book.
Basically, my question was this: For an engine with dual electronic
ignitions, would I be better off with two batteries and one alternator, or
one battery and two alternators (removing all other variables, and assuming
the batteries are well-maintained)?
You said the following (among other things):
Depends on what you choose to worry about. A PROPERLY MAINTAINED
RG battery is the single most reliable power source you can put
in your airplane. Could you run dual electronic ignition systems
from their own fuses on a single battery bus? Sure.
Now, what about alternator-out operations. With one alternator
and a DESIGN REQUIREMENT that you can exhaust fuel before your
battery(ies) run down may suggest some variations on the theme.
An AUX battery more than a year old and less than two years
old running ONE ignition system says that in the extreme case
of running the main battery flat with e-bus loads, the engine
keeps running. Alternatively, if you're in a position to
get shed of vacuum operated accessories and the pump that
drives them, then a second alternator on the vacated vacuum
pump pad is a no-brainer decision.
Given that (the "no-brainer decision" comment), I was all ready to stick with
the Z-13 architecture for a dual electronic ignition engine.
Then I read a post of yours last Sunday where you said (in reply to someone
else):
> >
> > I was just amused at your statement on Z-13 because I thought that you
> > did not advocate this setup for dual electronic ignition?
Correct. Sometimes after a day of brain-wrestling with
these things all day at RAC, my thought train gets
derailed . . .
So, I guess what I'm looking for is some kind of statement akin to one of the
following:
"We at Aeroelectric Connection do not advocate using the Z-13 architecture
for an aircraft with dual electronic ignitions. We prefer dual batteries
instead."
or...
"We at the Aeroelectric Connection believe that the Z-13 architecture does
not have any greater chance of total electrical failure than a Z-11 system
with an aux battery. In fact, we think it's a better option, and it's
perfectly viable for use with dual electronic ignitions."
If you'd rather not make either of those statements (for liability reasons,
or whatever), I totally understand. I'm just trying to get a feel for your
opinion on the matter. Would you personally have any problem getting in an
airplane that uses the Z-13 architecture with dual electronic ignitions?
I'm trying to avoid the added weight of two full-size batteries, and I really
like the idea of having the SD-8 as a backup alternator instead. I'm also
trying to avoid the complexity of having a backup battery just for half of a
dual ignition system -- if that's even a logical position to take.
Can you put an end to the ambiguity (read: my confusion) one and for all?
Thanks much!
-Geoff
RV-8
__________________________________
http://search.yahoo.com
Message 44
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:10 PM 5/13/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "John Karnes" <jpkarnes@charter.net>
>
> > >Sounds like a dead short.
> > >It would pull down the voltage and the excess amperage would trip the
> > >breaker.
> >
> > I agree . . . check to make sure your diode on
> > the b-lead contactor isn't hooked up backwards
> > or shorted.
>
>How do I check to see if the diode is shorted? I know it's not backwards as
>I haven't changed it and it was working fine before.
Use your ohmmeter to check the resistance across the diode.
If it (or something else on the line is shorted) it will
read very low (less than 1 ohm) no matter which way you
attach the leads.
> Could the high heat in
>the engine compartment have caused this? (I'm talking HIGH heat!)
Not likely.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 45
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| Subject: | Re: Fw: Electric Bob - Microair Radio-Xpdr |
Wire Harness
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:23 PM 5/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
>
>
>----- Original Message -----
>From: Rick Fogerson
>To: aeroelectric-list@matronics.com
>Subject: Microair Radio-Xpdr Wire Harness
>
>
>Hi Bob,
>Are you going to be selling wiring harness's for the Microair radio or
>xpdr anytime soon?
>Rick Fogerson
Yes, I need to make some up tomorrow morning. Which ones do you
want?
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 46
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| Subject: | Re: AutoPilot Disconnect Brain |
Teaser-05/12/03
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:13 AM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: Robert McCallum
><robert.mccallum2@sympatico.ca>
>
>"Robert L. Nuckolls, III" wrote:
>
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
> >
> >
> > >2,000,000 square inches (.318845 acres)
> >
> > ??????
>
>This would be the answer when you are trying to demonstrate your stupidity
>by leaving out half the
>formula in the rush to get to the dinner table after being called three
>times, then not even
>bothering with a reasonability check before pushing the send button.
>(feeling a little silly)
Understand . . . I try to limit my silly episodes to one per day.
Bob . . .
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