Flying with the Carb-Heat on for a long(er) tour?

Hi,
After taking two passengers on SF-Bay tours, I realized that I
want to take the tour slower... A north-bay tour (SF, GGB, Ocean
Beach, without the 101/Bravo transition) takes about 40min roundtrip
from OAK - a little quick.

I've been used to flying with the rpm around the bottom of the
green arc for this kind of thing, as my CFI used to always remind me
that "Carb-Heat introduces unfiltered air [into the carb]" which is a
bad thing...

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

Thanks for any comments,
Noah

"noah" wrote in message om...

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

Most of the dirt is pretty close to the ground. Unless you're flying through
a duststorm or volcanic erruption, at altitude there shouldn't be much harm
in leaving the heat on.

My thread isn't really on-topic, but I just had to chime in. The SF Bay
tour is such a charge to take friends with you on. While I've certainly
taken some on the $100 hamburger stops, nothing has quite inspired the oohs
and aahhs as the SF Bay Tour. I'm so glad that the Fatherland... oops I
mean Homeland security , hasn't been needlessly paranoid and allowed the SF
Bay Tours...

--
--
Good Flights!

Cecil E. Chapman, Jr.
PP-ASEL

"We who fly do so for the love of flying.
We are alive in the air with this miracle
that lies in our hands and beneath our feet"

- Cecil Day Lewis-

Check out my personal flying adventures: www.bayareapilot.com
"noah" wrote in message
om...
Hi,
After taking two passengers on SF-Bay tours, I realized that I
want to take the tour slower... A north-bay tour (SF, GGB, Ocean
Beach, without the 101/Bravo transition) takes about 40min roundtrip
from OAK - a little quick.

I've been used to flying with the rpm around the bottom of the
green arc for this kind of thing, as my CFI used to always remind me
that "Carb-Heat introduces unfiltered air [into the carb]" which is a
bad thing...

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

Thanks for any comments,
Noah

"noah" wrote in message
om...
Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on?

Just remember to lean the engine. Technically, at that altitude you
theoretically wouldn't need to, based on the POH. But in reality, even
without the carb heat, leaning in cruise regardless of altitude is a fine
thing, and especially with the enrichened mixture caused by the carb heat,
it's nice for the engine.

Pete

I just want to take this opportunity to totally, 100%, and unreservedly
agree with Peter

--
Roger Long

Peter Duniho wrote in message
...
"noah" wrote in message
om...
Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on?

Just remember to lean the engine. Technically, at that altitude you
theoretically wouldn't need to, based on the POH. But in reality, even
without the carb heat, leaning in cruise regardless of altitude is a fine
thing, and especially with the enrichened mixture caused by the carb heat,
it's nice for the engine.

Pete

noah wrote:

Hi,
After taking two passengers on SF-Bay tours, I realized that I
want to take the tour slower... A north-bay tour (SF, GGB, Ocean
Beach, without the 101/Bravo transition) takes about 40min roundtrip
from OAK - a little quick.

I've been used to flying with the rpm around the bottom of the
green arc for this kind of thing, as my CFI used to always remind me
that "Carb-Heat introduces unfiltered air [into the carb]" which is a
bad thing...

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

The Cessna Pilots Assoc, in its systems and procedures courses,
reccomends that you use whatever amount of carb heat it takes to keep
the carb temp above freezing. You are doing no damage.

In article ,
(noah) wrote:


I've been used to flying with the rpm around the bottom of the
green arc for this kind of thing, as my CFI used to always remind me
that "Carb-Heat introduces unfiltered air [into the carb]" which is a
bad thing...

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

Just because you're RPM is below the green arc doesn't mean you'll
develop carb ice. In fact with a carb air temp gauge you might find
that at high power settings you're colder than at low power settings.

Try it without the carb heat. If you notice any roughness or RPM drop
apply heat.

The O-470 in a 182 makes more ice than most Frigidaires. I never flew
with the carb heat on constantly and I never had any carb ice problems.
I also had a carb air temp gauge.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

noah wrote:

Basically - is it bad for the aircraft (C172) to float around at
around 85kts with the power somewhere below the green arc (say
1800rpm) and the Carb-Heat on? Ok, there is a second benefit - my club
charges based on tach time, and I have to be honest about that -
although I really do wish for the tours to be slower.

No problem, but, as Peter says, lean the engine.

George Patterson
If you're not part of the solution, you can make a lot of money prolonging
the problem.

"Roger Long" om wrote in
message ...
I just want to take this opportunity to totally, 100%, and unreservedly
agree with Peter

I know you do that just to **** me off!

Peter,

echnically, at that altitude you
theoretically wouldn't need to, based on the POH.


Wrong. Most all POHs tell you to lean at any altitude AT CRUISE POWER
SETTINGS.

--
Thomas Borchert (EDDH)