LOP operation

On Wed, 14 Apr 2004 22:36:41 -0700, "kage"
wrote:

Even John Deakin burned out a set of
Continental cylinders in 500 hours LOP in his Bonanza. And their highly
touted fuel savings are, for the most part, due to a decrease in speed. You
know, all that drag increase with V squared.

I'd hesitate to speak for Mr. Deakin but I'd venture that he'd
disagree violently that running lean of peak burned out his cylinders.
Since running lean of peak results in low temperatures and less gas
being burned, how exactly did they get burned out?

To demonstrate that running lean of peak does not necessarily mean a
lost of power, his "Mixture Magic" column showed a color photo of an
instrument panel of a Cessna 410 running one engine ROP and the other
LOP. Both engines were producing exactly the same power but at
different manifold pressures. The LOP engine was using less fuel and
was running at lower CHT temps. How is that bad?

CHTs are just fine ROP.

Actually they aren't, if you set the engine according to the POH.
Running at 75% or 80% power and set 50 degrees ROP, the CHT's run
above 400 degrees. These are figures that come from Lycoming and
Continental. And yet over 400 degrees is where aluminum begins to
loose strength. Deakin also was able to demonstrate that at certain
POH dictated ROP settings, the cylinders actually distorted from the
heat and began to scuff the pistons. This was during flight testing
with several proprietary probes installed in his engine which could
read what was happening in areas away from the cylinderhead probe.
While these probes were showing alarming increases in heat, the
cylinderhead readings read normal. He had to terminate the testing at
those settings because the readings at the bases of the cylinders were
rapidly rising, indicating that the pistons were beginning to scuff.

Engines run clean enough ROP.
Engine stresses have been doing just fine now for 100 years ROP.
CO is not a problem in maintained exhaust systems.
Airplanes fly faster ROP.

Not necessarily. Same rpm, same airspeed but higher manifold pressure
at the LOP settings equals the same cruise speed. Yes, if you want to
fly at best power, you should be running ROP.

Even the LOP diehards admit engines run smoother ROP.
Gamis have more value in a turbocharged engine.

Once again, not necessarily. Once the GAMI injectors are installed,
Deakin has been able to lean right to the point of having the engine
quit due to a mixture too lean to fire, without any roughness at all.
If there's roughness then the injectors are not matched properly.

Corky Scott