From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: IO-550 fuel injection system
To: lml
Date: Thu, 01 Feb 2007 21:39:42 -0500
Message-ID: <web-1805503@logan.com>
In-Reply-To: <270445.16473.qm@web34914.mail.mud.yahoo.com>
References: <270445.16473.qm@web34914.mail.mud.yahoo.com>
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Posted for bob mackey <n103md@yahoo.com>:

  Perhaps Hamid may have misinterpretted my comments.

   I offer the Toyota comparison simply as an example of good engineering.
   I never said my 115 HP Toyota four banger was an ideal replacement for
   a Continental IO-550 operating at -60F and FL260. What I said is that
   it was better engineered to do the job it was designed to do, and operates
   with very low operator workload.

   I am a pretty good engineer myself, and have quite a bit of experience
   designing, building, and driving race cars, including several national
championships.
   I know from that experience that many racers are willing to accept the
   limitations of off-the-shelf technology. These racers are rarely found in
   the winner's circle. Other racers are constantly questioning the status quo
   to find an opportunity for improvement. These are the guys or girls at the
front
   when the checkered flap drops.


   I'd like to think that most of us, as experimental aircraft builders are
also
   willing to improve on the status quo. The fuel system of the IO-550 is
   clearly an area that is ripe for improvement. I say this based not on
   my personal experience, but rather based on the experiences of those
   who have written about hi boost, lo boost, surging, vapor lock, and
   the sudden silence of engine stoppage. One pilot also reports that
   the engine won't stop when the mixture is pulled if the boost pump is on.


   I'd like to think that at least a few of us are willing to put in the 
effort
   to improve the safety and performance of that fuel system. Sure the
   monkey can be trained to flip the switches and twiddle the knobs so
   the noise maker keeps making noise, but I suspect there is a better
   way based on better engineering.

   Each of is our own Safety Tsar. Personally, I wouldn't have it any
   other way.This Safety Tsar would not approve an IO-550 for
   use in my aircraft without a better fuel pressure regulation system
   at the least. Better yet, a fuel metering system based on mass air flow
   or speed-density.

   PS - thanks to Gary Casey for explaining the function, "features",
   and resulting variations in the Continental Speed-Theta injection metering
   system. He thought the problem through, and then chose an injection system
   with Airflow-based metering (Lycoming IO-540 ?) for his aircraft.


   -bob mackey