john wrote:
The CFI no longer flies out of that airport, so I don't have contact
with him. I'm interested in others opinions related to rpm settings.
Is there any harm to the engine with reducing the RPM even lower, say
2200 or even 2100 RPM. I will confess to bringing it back to as low
as 1800 for a short X-C and found it to be good slow flight practice.,
which gave my one leg a work out in order to keep the bubble in the
middle. I wouldn't want to make many flights at 1800 though.

In the 172 I have reduced fuel from over 7.5 gph at 2400rpm to about
5.5 gph at 2200-2300.


The 1981 C-172P POH I just looked at listed 2100-2450 as the normal operating
range at sea level. The redline climbs with altitude to as much as 2700 rpm at
10,000 feet but it doesn't drop below 2100 on the lower end.

One thought about continued flight at 1800 rpm: if you were running with the
carb heat on to avoid icing, then you're ingesting unfiltered air. Best to keep
that at a minimum if you can.



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com