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Date: Wed, 18 May 2011 18:46:55 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Reliably starting
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On 05/18/2011 06:24 PM, Ed Anderson wrote:
> One thing my precepitions  is that your are starting to get close to 
> violating  the old Keep it Simple Stupid principle.  The more 
> components, the more redundancy, the more things that could go wrong 
> with the systems and there perhaps unintended interaction.  Not saying 
> there should not be any redundancy - that is why I fly with the EC  
> after my HALTECH system went belly up (fortunately on the ground).  
> But, you gotta know where to draw the line.
>   Another factor is that unless these systems are automatic, you will 
> find your time (and attention span) somewhat limited when things start 
> to go wrong (don't ask me how I know).
>
>
Component count is important, but system interaction is where the 
complexity really comes from.  Compartmentalized pieces with simple 
interfaces is my approach to driving out the complexity demons.  I have 
two ignition controllers that both run under the guidance of the ECU.  
Sounds complex, but there are only two signals to worry about.  One is 
the EDIS talking to the MS.  The other is the MS talking to the EDIS.  
If the communication breaks down, the EDIS automatically run 
independently.  One has it's own power source to make it more redundant, 
much like a magneto.  Just a dedicated, bone simple, 70W PM generator.  
Because of the way the VRs are mounted, I can depend on the battle 
hardened electronics to drive a pulse that may not occur at the most 
optimum advance, but at least close enough to keep the engine going.

The fuel backup is just a line with a control valve.  Doesn't get much 
more primitive than that.

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    On 05/18/2011 06:24 PM, Ed Anderson wrote:
    <blockquote cite="mid:list-4987941@logan.com" type="cite">
      <meta content="text/html; charset=ISO-8859-1"
        http-equiv="Content-Type">
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      <div><font face="Arial">One thing my&nbsp;precepitions &nbsp;is that your
          are starting to get close to violating &nbsp;the old Keep it Simple
          Stupid principle.&nbsp; The more components, the more redundancy,
          the more things that could go wrong with the systems and there
          perhaps unintended interaction.&nbsp; Not saying there should not
          be any redundancy - that is why I fly with the EC&nbsp; after my
          HALTECH system went belly up (fortunately on the ground).&nbsp;
          But, you gotta know where to draw the line.</font></div>
      <div>&nbsp;</div>
      <div><font face="Arial">&nbsp; Another factor is that unless these
          systems are automatic, you will find your time (and attention
          span) somewhat limited when things start to go wrong (don't
          ask me how I know).</font></div>
      <div>&nbsp;<br>
      </div>
      <br>
    </blockquote>
    Component count is important, but system interaction is where the
    complexity really comes from.&nbsp; Compartmentalized pieces with simple
    interfaces is my approach to driving out the complexity demons.&nbsp; I
    have two ignition controllers that both run under the guidance of
    the ECU.&nbsp; Sounds complex, but there are only two signals to worry
    about.&nbsp; One is the EDIS talking to the MS.&nbsp; The other is the MS
    talking to the EDIS.&nbsp; If the communication breaks down, the EDIS
    automatically run independently.&nbsp; One has it's own power source to
    make it more redundant, much like a magneto.&nbsp; Just a dedicated, bone
    simple, 70W PM generator.&nbsp; Because of the way the VRs are mounted, I
    can depend on the battle hardened electronics to drive a pulse that
    may not occur at the most optimum advance, but at least close enough
    to keep the engine going.<br>
    <br>
    The fuel backup is just a line with a control valve.&nbsp; Doesn't get
    much more primitive than that.<br>
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