50 degrees rich of peak

Ok. Just want to see if I have this correct. When leaning using an EGT
gauge the 172R POH says to lean untill the EGT needle peaks then enrich to
50 degrees F rich of peak EGT.

So the EGT temperature will be 50 degrees less than the peak reading.
Right?

Right. Your understanding of what 50 degrees rich of peak means is
correct.

Whether that's a good way to operate the engine is highly debatable.

Michael

lardsoup wrote:

So the EGT temperature will be 50 degrees less than the peak reading.
Right?

Slowly roll out the mixture lever watching the EGT gauge. When the
temperature on the EGT gauge peaks and begins to fall, roll in the mixture
lever until the temperature peaks, then keep rolling it inward until the
temperature needle falls 50 degrees below (or less than) the peak
temperature you witnessed.

--
Peter


















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Depends on if you want best power or best range. 50 degrees is for best
range, and 75 for best power if you don't want to crisp your valves.
Think of the heat in the valve section....excess fuel cools the valves
and that is what the EGT is doing for you.

Lardsoup,

go to www.avweb.com and search for columns by John Deakin on engine
management. Read them all. They will answer your question - and tell
you much more that's really good to know. Fun to read, too.

--
Thomas Borchert (EDDH)

lardsoup wrote:
Ok. Just want to see if I have this correct. When leaning using an EGT
gauge the 172R POH says to lean untill the EGT needle peaks then enrich to
50 degrees F rich of peak EGT.

So the EGT temperature will be 50 degrees less than the peak reading.
Right?


Yes.



--
Mortimer Schnerd, RN

VE

lardsoup,

You are correct in the interpretation, however, do not run the engine
at that power setting, it's about the worst possible for it.

As stated above, read John Deakin's columns in AVweb about what's going
on inside the engine. Either run it about 100 degrees rich of peak or
slightly lean of peak, although, thankfully on the little GA engines so
long as you are at 65% power or less you can't hurt them, the temps and
pressures don't get high enough.

All the best,
Rick

selway,

You might want to read Deakin's articles on engine ops in AVweb.

Crisping or burning the valves is an oft repeated, but untrue
statement. It is without any data to support it.

All the best,
Rick

"Michael" wrote in message
ups.com...
Right. Your understanding of what 50 degrees rich of peak means is
correct.

Whether that's a good way to operate the engine is highly debatable.


The actual and extensive data shows it's about the worst place you can
operate. That's in terms of both CHT and cylinder pressures.

wrote:

As stated above, read John Deakin's columns in AVweb about what's going
on inside the engine. Either run it about 100 degrees rich of peak or
slightly lean of peak, although, thankfully on the little GA engines so
long as you are at 65% power or less you can't hurt them, the temps and
pressures don't get high enough.

The OP cannot be faulted for leaning as per the POH. The late model C172
R and S model POH (page 4-26) recommends 50 degrees lean of peak. I would
suspect the OP is simply following the POH recommendation.

And before you flame me for simply pointing out this fact, keep in mind
that I am a 60-80 degree lean-of-peak leaner. :-)

--
Peter


















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