Today's Message Index:
----------------------
1. 05:50 AM - Re: Mechanical battery switch-ATTN BN III (Ernest Christley)
2. 06:03 AM - Re: Mechanical battery switch-ATTN BN III (Ernest Christley)
3. 07:54 AM - Re: Z-14 with dual Lightspeed III and SD-8 (bcondrey)
4. 08:36 AM - Re: 180 keyway washers (John Morgensen)
5. 09:05 AM - Re: Re: Z-14 with dual Lightspeed III and SD-8 ()
6. 09:37 AM - Re: 180 keyway washers (Bob White)
7. 10:59 AM - Re: Re: Z-14 with dual Lightspeed III and SD-8 (Robert L. Nuckolls, III)
8. 11:29 AM - Re: Re: Z-14 with dual Lightspeed III and SD-8 (Robert L. Nuckolls, III)
9. 11:48 AM - Re: Mechanical battery switch-ATTN BN III (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: Mechanical battery switch-ATTN BN III |
Fergus Kyle wrote:
> Bob,
>
> I may have sent a message to your private address, and it's
> not monitored. However you sent me the subject diagram and I've begun to
> fabricate a form of it. I couldn't find any useful acetal version of Delrin
> nearby so opted for a slab of Phenolic which is several layers deep. Also I
> can't find any brass 5/16-24 stock so am going with 5/16 toilet stock which
> is coarser but hopefully usable.
>
The use of the delrin is for isolation, for the most part. There is
also going to be some mechanical gymnastics involved in isolating the
cable. Is all that really necessary? We tend to get caught up on the
idea that the positive lead of the battery has to have the switch;
however, for isolation purposes it is just as valid to interrupt the
negative lead. Isolation in the reference design could be simplified to
two vinyl shoulder washers for one of the 5/16 brass all-thread leads
(the one attached to the battery). Everything else could be safely
grounded to a metal airplane. In fact, it could safely BE the ground in
an all metal airplane, and only have one piece of all-thread and one
plunger, cutting the smaller area connections in half .
I don't have the time to do a CAD drawing, but I now think I will be
using a design composed of a piece of hat section aluminum about
1"x1"x1" with 3/8" flanges, riveted to a steel gusset (I'm building a
steel tube frame aircraft). The allthread mounts in a hole in the top
of the hat, the plunger through a threaded hole in the gusset. The
slider is just a brass plug that grounds the allthread to everything
else, until it is pulled.
Message 2
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Subject: | Re: Mechanical battery switch-ATTN BN III |
Fergus Kyle wrote:
> Bob,
>
> I may have sent a message to your private address, and it's
> not monitored. However you sent me the subject diagram and I've begun to
> fabricate a form of it. I couldn't find any useful acetal version of Delrin
> nearby so opted for a slab of Phenolic which is several layers deep. Also I
> can't find any brass 5/16-24 stock so am going with 5/16 toilet stock which
> is coarser but hopefully usable.
>
As a followup to my last post, I left out one point. The plunger could
be replaced with a short piece of stainless flat spring shaped like a
bow, riveted at the entrance and exit of the hat to leave a hump in the
middle. A slight depression filed into the center of the brass bar that
the spring settled into would provide for positive retention.
Message 3
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Subject: | Re: Z-14 with dual Lightspeed III and SD-8 |
Bob,
Direction to use CBs is in the installation literature, however no specific or
caution against fuses is not. This came up during a conversation when I mentioned
driving the ignitions off the battery buss fuse blocks.
Bob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=228169#228169
Message 4
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Subject: | Re: 180 keyway washers |
JohnInReno wrote:
>
> Does anyone have a source for keyway washers that are 180 degrees out from the
standard? The standard washers have the key and the tab together but I am looking
for ones with the tab opposite the key.
>
> Thanks,
> John Morgensen
>
> --------
> RV-9A - Fuselage
> Grumman AA1B-150 (RV-Trainer) Flying
>
>
Oops! I am inquiring about the 700 series of toggle switches.
john
Message 5
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Subject: | Re: Z-14 with dual Lightspeed III and SD-8 |
This whole thing gives me the willies, but I'm in the same boat and not
jumping off. I'm gonna buy 2 CB's and hog tie them to the battery. Oddly
enough they will be wired through a switch on the panel which is another
point of failure. Perhaps I'll braze the fast tabs on so they don't fly
off over a bump. We could also fly around with a spare battery at our
feet and two alligator clips drooping down from the panel. In an
emergency, just hook them up. I guess it's just a matter of what one is
comfortable with. Different strokes for different paranoia's.
On a similar note, in the recent KitPlanes mag there is an article
about Precision's "near" FADEC system which requires the whole system is
wired to a separate battery. In this they are taking the next step to
completely isolate dependency on the primary battery components.
Perhaps that is a good first step. Just add a battery in series and wire
the 2 CB's to it.
Glenn
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Sent: Sunday, February 01, 2009 9:45 PM
Subject: AeroElectric-List: Re: Z-14 with dual Lightspeed III and SD-8
<nuckolls.bob@aeroelectric.com>
At 03:28 PM 1/31/2009, you wrote:
><bob.condrey@baesystems.com>
>
>Food for thought for those with dual LSE ignitions (like me). I was
>talking with Klaus about his CB recommendation vs fuses and he said
>that the ignitions (at least the Plasma IIIs that I have) have an
>internal crowbar circuit to protect the ignition from an overvoltage
>event. Reason for the CB recommendation was so that in the unlikely
>case of an OV event the pilot could pull the alternator CBs, reset
>the ignition CBs and continue flight.
That is unfortunate. Is this feature
mentioned in the installation literature?
Under the right conditions of alternator
size, battery condition and system loads,
an OV event could trip BOTH ignition systems
leaving you with a cold engine.
The whole idea behind the 20V, 1-Second surge
test under DO-160 was to open an OV
shutdown opportunity as big as a barn door. Any
product designed with rudimentary attention
to DO-160 in mind will not even have to grunt
hard during an OV detection and shutdown.
Response to OV conditions are best handled
by devices crafted to slay the dragon in his
cave as opposed to chasing him down in the
wild.
>This was the first time I'd ever heard this and it scared me A LOT
>because I've got mine wired through my battery buss fuse blocks
>(Z-14). While I've never had a problem and haven't heard of anybody
>else having a problem, I plan to redo the ignition power wiring and
>switch to CBs.
It would scare me too. It's unfortunate
that a feature of this accessory drives
the installer's system architecture. Bottom
line is you gotta do what you gotta do
. . . even if it sucks for air.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 6
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Subject: | Re: 180 keyway washers |
Hi John,
Why not notch the panel to fit the washer? Both notches will be
covered when the switch is installed.
Bob W.
On Mon, 02 Feb 2009 08:34:44 -0800
John Morgensen <john@morgensen.com> wrote:
>
> JohnInReno wrote:
> >
> > Does anyone have a source for keyway washers that are 180 degrees out from
the standard? The standard washers have the key and the tab together but I am
looking for ones with the tab opposite the key.
> >
> > Thanks,
> > John Morgensen
> >
> > --------
> > RV-9A - Fuselage
> > Grumman AA1B-150 (RV-Trainer) Flying
> >
> >
> Oops! I am inquiring about the 700 series of toggle switches.
> john
>
>
>
>
--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://roblinstores.com/
Message 7
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Subject: | Re: Z-14 with dual Lightspeed III and SD-8 |
At 09:52 AM 2/2/2009, you wrote:
><bob.condrey@baesystems.com>
>
>
>Direction to use CBs is in the installation literature, however no
>specific or caution against fuses is not. This came up during a
>conversation when I mentioned driving the ignitions off the battery
>buss fuse blocks.
No, I was asking about the built in crowbar ov
protection. To include such a feature without
specific explanation of its value, installation
and operation would not be viewed with benevolence
among the designers I work with.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 8
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Subject: | Re: Z-14 with dual Lightspeed III and SD-8 |
> This whole thing gives me the willies, but I'm in the same boat and not
>jumping off. I'm gonna buy 2 CB's and hog tie them to the battery. Oddly
>enough they will be wired through a switch on the panel which is another
>point of failure. Perhaps I'll braze the fast tabs on so they don't fly
>off over a bump. We could also fly around with a spare battery at our
>feet and two alligator clips drooping down from the panel. In an
>emergency, just hook them up. I guess it's just a matter of what one is
>comfortable with. Different strokes for different paranoia's.
>
>
> On a similar note, in the recent KitPlanes mag there is an article
>about Precision's "near" FADEC system which requires the whole system is
>wired to a separate battery. In this they are taking the next step to
>completely isolate dependency on the primary battery components.
>
>Perhaps that is a good first step. Just add a battery in series and wire
>the 2 CB's to it.
"Perhaps it's a good first step" is not a well directed
thought process. While motivations of most builders is
to shrug off the debilitating effects of self-serving
regulation, the history of TC aviation is rich with examples
of successful repeatable experiments. Ever watch an
episode of "House"? There is a thought process demonstrated
in every episode where the characters participate in
a "diagnosis differential." In aviation we all it
a failure modes effects analysis (FMEA). This experiment
is repeated in the operation of ANY successful sifting
of simple-ideas looking for the optimized combination
that meets design goals.
If OBAM aviation suffers from any debilitating if not
dangerous faults, it's the lack of diagnosis differential
discussions amongst successful practitioners of the craft.
The Lists, newsgroups and forums are replete with
discussion noteworthy for their emotional dithering
and stirring the pot of "idea-stew" which almost never
moves toward a cleanly distilled solution.
It's your airplanes guys . . . and your choice of
installed hardware. If it were my airplane and it came
with any built in OV protection that places the airplane
at risk, I would conduct the following study:
(1) What duration and magnitude of over voltage can
the "protected" appliance withstand by design?
Does it even come close to the spirit and intent
of DO-160 power input recommendations?
(2) Can the supplier offer me product with the OV
protection disabled if I accept the system integrator's
responsibility for assuring that the product will not
be stressed beyond those limits quantified in
Mil-Std-704 and DO-160?
Pending assuring answers to those questions, I
would be strongly disposed to seek an alternative
product that meets my design goals. Of course,
I could craft special power sources for the products
that insure they're never presented with an over
voltage. How's that for a parts-count boondoggle?
Put in more parts to offset the undesirable effects
of parts that don't need to be there. In addition
to being surplus to the well crafted system, inclusion
of extra parts WITHOUT NOTIFYING the customer/installer
of their existence and function is inconsistent
with conduct I expect from an honorable supplier.
This isn't rocket science. It's not about customer
loyalty. It's not about performance at any risk.
There are well proven processes by which we can
minimize risk while meeting design goals and keeping
costs bearable. Operations outside those processes
is at best fearful and frustrating and at worst
hazardous.
Bob . . .
Message 9
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Subject: | Re: Mechanical battery switch-ATTN BN III |
At 03:53 PM 2/1/2009, you wrote:
>Bob,
> I may have sent a message to
> your private address, and its not monitored.
> However you sent me the subject diagram and
> Ive begun to fabricate a form of it. I
> couldnt find any useful acetal version of
> Delrin nearby so opted for a slab of Phenolic
> which is several layers deep. Also I cant find
> any brass 5/16-24 stock so am going with 5/16
> toilet stock which is coarser but hopefully usable.
> I hope this is satisfactory
> from a practical point of view I note the
> toilet kits are now yellow-coated steel as a
> partial scam. If it works Ill fire off a
> message describing it. At present my Main
> battery switch is a racing-car cut-off switch,
> so this will constitute a second battery switch
> thus saving me about 2+ amperes forever.
>Cheers, Ferg
Ferg, if you're ordering spring-loaded ball plungers
from McMaster, they also stock 5/16-24 brass rod
stock. They also stock Delrin but I have some scraps
of 1 x 1 inch Delrin I can send you. The plated steel
parts are NOT suited to this task.
Bob . . .
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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