From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: Extending range [fadec]
To: lml
Date: Sun, 28 Nov 2004 15:07:59 -0500
Message-ID: <web-548371@logan.com>
In-Reply-To: <00ab01c4d561$b571e1e0$3a920218@attbi.com>
References: <list-545829@logan.com>
 <00ab01c4d561$b571e1e0$3a920218@attbi.com>
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Posted for "Jabe Luttrell" <JabeLuttrell@comcast.net>:

  Hello Walter,
  
  Thanks for the reply.  I think a few points you opine need to be addressed.
  
  1. The fact that the PowerLink(TM) FADEC control system has the ability to
enrichen the mixture when the CHTs reach the control limits, doesn't mean or
imply that the CHTs actually reach the control limits on takeoff or at other
times.  In my flight experience with the system and with my experience
analyzing the data from dyno, prop stand, and other airplanes using the system
I find that the CHTs seldom reach 400F with correct cooling baffles.
  
  2. Full rich mixture limit is a rated limit.  It not a normal control 
target.
  The PowerLink(TM) FADEC system typically does not operate at that limit.  We
do, however, test that the full rich mixture fuel flows can be attained.
  
  3. The PowerLink(TM) FADEC does not target CHT redlines.  Its control limits
are less than the redlines.  In practice the control limits are not reached
during takeoff.
  
  4. The PowerLink(TM) FADEC tuning does not use degrees LOP or ROP.  It is
tuned to the measured minimum BSFC for economy and peak power for Best Power.
  And yes it does adjust for every power condition the pilot sets.  The entire
operating envelope for each engine has been mapped into the PowerLink(TM)
FADEC computers.
  
  5. It was nice of you to take credit for the cockpit mixture switch.  Your
opinion, unknown to us, wasn't the basis for the inclusion of the switch.  It
was added for both fixed pitch prop applications and constant speed (not pilot
selected variable) applications and was considered useful in all applications.
  
  6. Regarding the 30-year old injection system, I think you'll agree that
engine control technology has improved in 30 years.  Electronics and
injectors, too, are much faster.  The PowerLink(TM) FADEC injectors are off
more than half the time, even at takeoff.  I know I don't have a manual choke
or carburetor on my car anymore.  I don't have points or a distributor either.
  And I don't pine for the manual controls.  With the advent of glass cockpits
and the need for additional sophisticated training for pilots to operate the
"glass" TAA airplanes, imposing the continuous need for manual engine control
on the pilot is distracting from his real duties of flying the plane.  No
matter how frequently you proffer that the mixture should be adjusted, the
PowerLink(TM) FADEC will adjust it at the maximum rate of every engine cycle
for every cylinder.
  
  7. With regards to fuel flows, our, controlled, dyno and side-by-side tests,
in the same environment, at the same time, show real fuel savings.
  
  8. Sensor failure in the PowerLink(TM) FADEC system do not automatically
adjust the mixture to Full Rich.  It is incorrect to suggest that this the
response to failure modes.
  
  9. With regards to service, the TCM field service system supports this
product.  Service centers will grow in number with the rate of introduction.
  Parts are available.  Oil and plugs do stay cleaner longer, because the
engine is run at leaner mixtures.  In general the system needs less service
than the magneto-mechanical injection system.
  
  Jabe Luttrell