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Date: Mon, 21 Feb 2005 15:07:28 -0500
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From: Walter Atkinson <walter@advancedpilot.com>
Subject: Re: [LML] Re: FADEC Rough idle explanation

Gary:

Those answers are commonly offered.  Before George or I respond to 
them, any other thoughts from anyone else?

Walter


On Feb 21, 2005, at 9:00 AM, Gary Casey wrote:

<<Posted for "George Braly" <gwbraly@gami.com>:

   Want to try to define a list of what you think will be "better"  and 
why
   with FADEC than it will be with a well managed conventional engine?>>

I'm not an expert in Continental's version of FADEC, but I think if one
looked at the generic possibilities of a "good" FADEC system it would go
something like this:

   Hp ? - no difference as the spark timing of a conventional system is
probably about right for best power and the mixture was set for
cooling/detonation so nothing can be done there (not not always true).  
The
Lycomings have a venturi that restricts the flow, so a speed-density 
system
would have slight advantage there (up to 3%).

   BSFC ? - I think there would be an advantage to the FADEC, but only at
high altitudes/low MAP when the standard system can't advance the spark.

   CHT ? - no significant difference that I can think of.

   Price ? - Any FADEC system will almost certainly cost more.  Maybe 
quite a
bit more.

   TBO ? - There might be no difference as while the electronics can be
expected to last forever the injectors won't.  The conventional system 
can
be rebuilt any number of times.

   Weight ? - If a distributorless system is used the FADEC will almost
certainly weigh more as multiple ignition coils probably weigh more than
one.

   Other ? - The primary advantage of a FADEC system should be idle 
quality
(title of present thread not withstanding) and starting, as well as 
reduced
pilot workload.  How important are those things?

Gary Casey


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