Sender: "Marvin Kaye" <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Mon, 28 Feb 2005 15:56:05 -0500
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From: "Matt Hapgood" <hapgoodm94@alum.darden.edu>
Subject: RE: [LML] Re: FADEC Rough idle explanation
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In-Reply-To: <list-762667@logan.com>

I agree with both Adam and George (and you didn't think there was any common
ground!).

Electronic fuel metering is complex - really complex.  I've got a homebrew
EFI system - it doesn't have anything approaching the complexity and
redundancy that a certified system would require and it is still VERY
complex.  Lots to go wrong - lots to set up.

But, from an operators perspective, it is "turn the key and go".  No mixture
setting, no accidental lean take-offs, and it is always accurate (or at
least as accurate as I set it up to be years ago).

Do I really care about being able to "tune" the fuel flow while in flight -
hell no.  I want to focus on flying the plane.  Give me a choice between
best power or best economy and I would be thrilled.  Give me one or the
other at a specific power setting and I'll just pick the power setting I
want.

There IS a reason that the automotive industry went to EFI.  Taxi smaxi.
I'm not talking about sequential port injection vs. throttle body
injection - I'm talking about electronic fuel injection vs. carbureted or
mechanical injection - that's the comparison we are really talking about
here.  And electronic fuel metering IS less pilot input intensive.  It IS
more consistent.  It IS more idiot proof.  It IS at least as efficient, and
often more efficient, across the spectrum of operating regimes.  It IS
better.

We spend countless amounts of time on this list talking about accidents and
what could have been done to improve an outcome or increase safety.  Is
there ANYONE out there who believes that from a PILOT perspective that a
manually controlled mixture setting process is SAFER than an automatic
process?  Does anyone out there think that REDUCING pilot workload is a bad
thing?  Fouled plugs - anyone thought about the accident chain?  You'll
probably never read of an accident that is caused by improper mixture
setting, but how often is that a contributing factor?

So to me the only question is - how can we get a SAFE and RELIABLE
electronic fuel metering system - NOT whether it is a good thing or not.
Walter and George - the Prism system sounds wonderful - a great way to
increase engine life, power and efficiency.  But as far as I can tell it
doesn't do anything to reduce my workload.  As much as I like the timing
advantages PRISM promises, when it comes to spending many thousands of
dollars I'd be hard pressed to decide between it and and a system that
addresses timing, fuel metering and pilot workload (FADEC).

Walter, you may be a different type of pilot than me.  So I'll bore everyone
with a little analogy.  I used to do a bit of amateur car racing.  There are
always guys out there poo pooing EFI - they've got carburateurs and manual
chokes, and they rejet their carbs for practically every race.  They spend
countless hours getting their engines purring for each race.  I, on the
other hand, have EFI.  I show up, unload the car, tweak suspension settings
and downforce, and go racing.  The other guys are invariably faster at the
start of the race, but by the end of the race, there is a disproportionate
number of DNF's for those tuned-engine cars.  Holed pistons, sputtering
engines, or balled up in the hay bales as the driver was spending too much
time talking to the pit about engine glitches rather than driving the car.
But on the other hand, the tuned engine cars often won races - maybe they
were better tuners and eked out the very last bit of power.  Walter, I hope
you are one of them.  I am not - I use my airplane for transportation.

Flame suit on...

Matt