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

[noah]

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

[Ron Natalie]

"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.

[Cecil E. Chapman]

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

[Peter Duniho]

"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

[Roger Long]

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
>
>

[Newps]

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.

[Dale]

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

[G.R. Patterson III]

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.

[Peter Duniho]

"Roger Long" m> 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!

:)

[Thomas Borchert]

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)

[G.R. Patterson III]

Peter Duniho wrote:
>
> "Roger Long" m> 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!

You get upset when people agree with you?

That explains a lot.

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

[noah]

Thanks everyone for your replies...

Next time I'll fly with the rpm I want, and use Carb Heat below the
green arc as the POH recommends.

BTW: the Bay Tour definitely causes 'Ohh's and 'Ahh's. Even the first
two times I went (no pax) it was tough to stay focused on
traffic/airspace and not just enjoy the view. PS: Now (with pax) I
won't touch a camera at all, and just scan for traffic - as I've seen
quite a bit of traffic going North/South between the GGB and KHAF -
not to mention the low flying tours around the GGB and San Francisco.

Cheers,
Noah

[Peter Duniho]

"G.R. Patterson III" > wrote in message
...
> You get upset when people agree with you?

No, just Roger. I only get ****ed off because I know he's doing it to ****
me off.

:) (Smiley there. Just like in the last post, which you seemed to have
missed).

> That explains a lot.

Like what?

Pete

[Peter Duniho]

"Thomas Borchert" > wrote in message
...
> 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.

Wrong? Completely? So wrong that you found it so very important to follow
up to say so? Amazing. In any case...

Not all do. Many state or imply that leaning is not necessary below 3000'
or 5000', for example. And it may even be true that leaning isn't *really*
necessary, from an operational point of view. But engine will be much
happier if you do. I don't have the POH he's using, so I have no idea what
it says. My comments were offered purely in the hypothetical, so I don't
see how you can make an unqualified assertion that they were wrong.

My point is that, even if the POH says you don't need to lean, one ought to
anyway in this particular case. Do you disagree with the actual point, or
are you so hard up you find it necessary to critique embedded statements
that could be construed as being flatly incorrect, even when they aren't?

Pete

[Thomas Borchert]

Peter,

Hey, your fuse is really short (so what else is new?) ;-)

You and I know that "Don't lean below xxxx feet" is one of the baddest,
wrongest, silliest (are those words?) OWTs (Old Wive's Tales) in
aviation. So, IMHO, we need to do all we can to keep it from getting
propagated. That's all I was trying to do.

--
Thomas Borchert (EDDH)

[Peter Duniho]

"Thomas Borchert" > wrote in message
...
> Hey, your fuse is really short (so what else is new?) ;-)

Yes, I have a low tolerance for people like you who see a need to label a
person wrong, no matter how much you have to stretch your interpretation of
what they said to do it.

> You and I know that "Don't lean below xxxx feet" is one of the baddest,
> wrongest, silliest (are those words?) OWTs (Old Wive's Tales) in
> aviation. So, IMHO, we need to do all we can to keep it from getting
> propagated. That's all I was trying to do.

Not that I could tell. The ONLY thing your post claimed was that not all
POHs provide an altitude below which one doesn't lean the engine. Which is
true, but in no way contradicts anything I wrote.

You made no comment whatsoever regarding actual operations. You only
contested your perception of what I wrote (which wasn't accurate anyway).

Pete