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Date: Tue, 22 Feb 2005 23:22:26 -0600
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Using "conventional" aircraft ignition switches..
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On a BAD day, 20 amps would seriously lengthen the time you could fly on 
your battery, which after all is the object of the exercise.
Sounds like a GOOD backup alternator, not so good as a redundant 
alternator ... Jim S.

David Staten wrote:

> Isn't 20 amps excessive? I mean, the entire engine should run off 20 
> amps, not just one pair of coils...
>  
> Dave
>
> James Maher wrote:
>
>> Dave,
>> I use this switch with Tracy's EC-2 controller.
>> The coil disable inputs are wired to this switch and function when 
>> controller "B" is selected.
>> I also have 2 separate 20A breakers ( the push/pull type) that the 
>> coils and injector pairs get their power from so that they can be 
>> disabled when working on the engine.
>> Jim Maher
>>
>> */David Staten <Dastaten@earthlink.net>/* wrote:
>>
>>     Another "fishing trip" to ping the collective masses here.
>>      
>>     A little background:
>>     Typical "aircraft" key ignition switches for controlling magnetos
>>     operate by grounding out the mag to "disable" it. The commonly
>>     seen configuation is something that has OFF, L, R, BOTH and a
>>     START position.. On the L setting for Left Magneto, the right mag
>>     is actually grounded/disabled and vice versa for the R position.
>>     In addition, in some installations, the switch also disables the
>>     right mag for starting if the aircraft has a "retarded" mag on
>>     the left side.
>>      
>>     I am curious about the following switch:
>>     http://www.aircraftspruce.com/catalog/elpages/ignitionswitchkit.php
>>
>>     http://www.aircraftspruce.com/catalog/elpages/ignitionswitchkit.php
>>
>>     Wiring diagrams available at the link.
>>
>>                  
>>     I am wondering if anyone has hands on experience with these sorts
>>     of switches (from a wiring standpoint..
>>
>>     Does anyone know if this switch is reasonably/easily adaptable to
>>     selecting individual coil banks such as for "trailing" and
>>     "leading" when used in conjunction with an EC 2 setup?
>>      
>>     Is the ground terminal on this switch connected to the entire
>>     switch chassis or is it an isolated terminal ONLY used for
>>     grounding the mags (and if its isolated, could it safely be used
>>     as a low current "HOT" instead to power a coil relay? Or are
>>     there relays (which in turn control the coil packs) that can be
>>     reasonably set to open/disconnect when placed to ground? Or would
>>     having a relay with a ground trigger result in undesireable
>>     current flow through the switch or relay? I assume an Ignition
>>     Master switch to de-energize the whole thing would be needed in
>>     that case
>>      
>>     If useable, the implications would be great: A key switch for
>>     "security appearance" (A.K.A.. the New Jersey dual lock rule).
>>     Key-cycled control of both coils, AND a start switch all in one.
>>      
>>     The only DISADVANTAGE that I see is the difficulty in cranking
>>     the engine with the ignition OFF for whatever reason: preoiling,
>>     clearing a flood, priming etc. I would assume that the COILS
>>     circuit breaker would need to be pulled in that event.
>>      
>>     Dave
>>