Message-ID: <38835F72.28C22792@progress.com>
Date: Mon, 17 Jan 2000 13:29:06 -0500
From: Marcelo Pacheco <pacheco@progress.com>
Organization: PROGRESS Software Professional Services
To: lancair.list@olsusa.com
Subject: Re: power reduction
Mime-Version: 1.0

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For anybody that isn't convinced about why we shouldn't perform any
power reductions until it's time to level off, I sugest you read the
many articles about manifold pressure, RPM and mixture control on avweb.
Those articles are by John Deakin. This is a *general* idea, that
depends on your engine's operation. Exceptions can exist.

Also, I've seen mention to the word squared, which isn't quite the best
way to operate today's high performance engines. It's often much more
efficient and good to the engine to operate with lower RPM's and higher
MP's. This subject is also covered there.

My own conclusions after reading those very in depth but understandable
articles is that oversquare operation is good for as long as it's within
the engine's aproved performance envelope, as well as it's perfectly
acceptable to leave the throttle fully openned until leveling off,
unless it's documented in the engine's manual's otherwise. And for
normally aspirated engines, for a high altitude, long distance cruise,
often the best way to operate is to climb and cruise full throttle, just
reducing RPM once to climb RPM and again to cruise RPM, and leaning as
recommended.

Those 2 procedures come from the large radial, supercharged engines
found on the old piston airliners (for example the super constellation),
as well as turbine engines in general, but both are quite different
beasts when compared with today's piston engines.

What really matters is keeping the temps within recommended ranges.

Marcelo Pacheco
PP-ASEL IFR
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