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jpx(at)Qenesis.com Guest
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Posted: Sun Jan 27, 2008 10:09 pm Post subject: Z13-8 N P-Mags |
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You might think wiring up an electronic mag might be simple
Replacing the S700-2-10 with a S700-2-1 as I indicated in my previous
post isn't the correct solution. It does allow removing external
power to test the internal alternator, but in normal use, it removes
external power before grounding the P-Lead, which is clearly stated by
E-Mag as not the way to shut down the engine
At one point I had the design such that I used only three switches to
control power/ground to the mags, allowing testing and with a position
to engage the starter.
However, it used three expensive switches and I have encountered
poorer reliability with spring return types. The main problem really,
is that the power to both mags was routed through one single switch.
Since it is not being moved in flight, it is unlikely to fail, but ..
My current plan is to use four of the simplest single-pole on-off
switches, two for power and two for p-lead grounding, plus a push
button for start. So that is a total of five switches, but much
simpler and cheaper components and the plane will still fly if any one
of them fails.
I like the simple flow of operating the switches. However, I am not
completely comfortable without a keyswitch, which would be difficult
to include in this design. I do not like keyswitches, but there is a
clear delineation between someone being (or not) permitted to start
the aircraft if they are in possession of the key. To prevent
starting, the key would need to disconnect mag power to avoid hand
propping. The secret switch under the dash, used for auto anti-theft
is a safety of flight issue. Anyone have any good ideas how to handle
this ?
Jeff Page
Dream Aircraft Tundra #10
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nuckolls.bob(at)cox.net Guest
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Posted: Mon Jan 28, 2008 5:56 am Post subject: Z13-8 N P-Mags |
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At 01:06 AM 1/28/2008 -0500, you wrote:
Quote: |
You might think wiring up an electronic mag might be simple
Replacing the S700-2-10 with a S700-2-1 as I indicated in my previous
post isn't the correct solution. . . .
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<snip>
Quote: | My current plan is to use four of the simplest single-pole on-off
switches, two for power and two for p-lead grounding, plus a push
button for start. So that is a total of five switches, but much
simpler and cheaper components and the plane will still fly if any one
of them fails.
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Hmmmm . . . I take it that you have not read my response
to your original posting on this topic. Stand the circuit
as-published against the design goals stated and see if your
concerns are not already addressed by the proposed two-switch
configuration.
Quote: | I like the simple flow of operating the switches. However, I am not
completely comfortable without a keyswitch, which would be difficult
to include in this design. I do not like keyswitches, but there is a
clear delineation between someone being (or not) permitted to start
the aircraft if they are in possession of the key. To prevent
starting, the key would need to disconnect mag power to avoid hand
propping. The secret switch under the dash, used for auto anti-theft
is a safety of flight issue. Anyone have any good ideas how to handle
this ?
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What are the risks? How many folks of dishonorable behavior
know how to fly YOUR airplane? Hundreds of airplanes are
subjected to evil intent every year. Radios and instruments
are stolen, airframes vandalized but exceedingly few airplanes
are removed from their parking places. The most effective
theft deterrents are the simplest. Folks who want whole airplanes
are generally professional drug runners and the hauling ability
of an SE lightplane is simply not in conformance with their
business model. One of my favorite deterrents is used by several
folks at ICT. See:
http://www.aeroelectric.com/Pictures/Misc/AC_Theft_Protection.jpg
THIS airplane would haul a LOT of pot . . .
The whole idea of a "secret switch" doesn't consider the
mind-set of folks who prey upon others. If he/she goes
to work on your airplane only to find that the "puzzle"
is beyond their ability solve, they're more likely to
take out their frustration with a hammer to your panel
or a knife to your upholstery or canopy.
Thieves are a lazy lot, else they would make their living
by exploiting their own productiveness as opposed
to exploiting the products of others. Hence a hardened
steel chain and lock is very likely to send your antagonist
off to "greener" pastures. If you make the solution to
the puzzle quite clear from the get-go, they're more likely
to go in search of easier prey.
I had a hangar renter at 1K1 ask me NOT to lock his
airplane. He had to do thousands of dollars of work
to repair damage to doors over the years and thieves
got his radios anyhow. He correctly deduced that it
was a whole lot less expensive to leave the doors
unlocked and just have to replace radios. Interestingly
enough, after his airplane was moved to our Podunk
International Airport (See
http://www.aeroelectric.com/Pictures/Misc/1K1_Spring_1989.jpg
he was not victim of any more attacks against his
airplane.
Bob . . .
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