Fuel Flow and Peak EGT

On Apr 30, 4:17 pm, Newps wrote:
First off gas is not cheaper than cylinders so that's a dumb argument
from the get go. At 65% you want to be leaner than peak EGT or richer
than 100 ROP for best engine health. At 75% you want to be leaner than
40 LOP or richer than 180 ROP. There are other power settings with
their own combos but these are the two most used. At your stated 65%
get yourself about 15-20 LOP. That's good for the engine and the loss
of airspeed is negligible. You can go leaner but you'll start to notice
a speed loss.



Kobra wrote:
What model engine? I often run LOP at those settings with a Lyc. O-360
F1A6.

I have an IO360 A1B6. I am embarrassed to say that I did not know, nor was
I ever taught, that below 65% power you could lean to peak without hurting
the engine. I have been wasting gas and money now since June of 2002. I am
really ashamed that I did not open my eyes. I just dismissed talk of LOP
and running at peak as bad advice without an engine analyzer. This is
because my instructor/A&P always said to run the engine 100 degrees ROP and
never to run LOP "because gas is cheaper than cylinders". I took his word
as gospel and have flown 75 to 100 degrees ROP ever since I bought my plane.

Even my type club said to me recently, "about 65% power and lean until your
hearts content..."

Thanks for all your help.

Kobra- Hide quoted text -

- Show quoted text -

Do these 65% v. 75% ROP & LOP temp limits have any relation to
compression ratio of the engine? In another words, if my engine is
7:1 CR & running at 75% power, can I run at temp limits for an engine
that is 8.5:1 CR running at 65%?

" wrote in message
ups.com...
On Apr 30, 4:17 pm, Newps wrote:
First off gas is not cheaper than cylinders so that's a dumb argument
from the get go. At 65% you want to be leaner than peak EGT or richer
than 100 ROP for best engine health. At 75% you want to be leaner than
40 LOP or richer than 180 ROP. There are other power settings with
their own combos but these are the two most used. At your stated 65%
get yourself about 15-20 LOP. That's good for the engine and the loss
of airspeed is negligible. You can go leaner but you'll start to notice
a speed loss.


Do these 65% v. 75% ROP & LOP temp limits have any relation to
compression ratio of the engine?

No, not really.

In another words, if my engine is
7:1 CR & running at 75% power, can I run at temp limits for an engine
that is 8.5:1 CR running at 65%?

Run at the temp limits defined (EGT/CHT) in your POH, where ever that fall
on the LOP graph.

http://www.avweb.com/news/pelican/182084-1.html (Plus the entire engine
series defined in the sidebar on the right).


--
Matt Barrow
Performace Homes, LLC.
Colorado Springs, CO