Turbo 182: correct mixture for final approach at high altitude?

"john smith" wrote in message
...
[...] Had you need to do a go
around, the cruise mixture would have been sufficient for a full power
go-around.

You do understand that he's talking about a turbocharged engine, right?
Generally speaking, full rich is the correct mixture setting for a
turbocharged piston engine, for full-power takeoffs regardless of altitude.

Pete

Peter Duniho wrote:

You do understand that he's talking about a turbocharged engine, right?
Generally speaking, full rich is the correct mixture setting for a
turbocharged piston engine, for full-power takeoffs regardless of altitude.


'Generally speaking', but not necessarily. Full-rich is the correct takeoff
setting for a FUEL-INJECTED engine regardless of altitude, but *not* for a
CARBURETED engine.

Most turbocharged engines are injected, but not all. In fact, the Turbo 182 has
one that isn't: a (carbureted) Lyc 0-540.

Really - my carbureted 182 calls for full rich on takeoff

"Mark Mallory" wrote in message
...


'Generally speaking', but not necessarily. Full-rich is the correct
takeoff
setting for a FUEL-INJECTED engine regardless of altitude, but *not* for a
CARBURETED engine.

Most turbocharged engines are injected, but not all. In fact, the Turbo
182 has
one that isn't: a (carbureted) Lyc 0-540.

Michael 182 wrote:
Really - my carbureted 182 calls for full rich on takeoff

So does mine - at SL on a standard day.

But not on a hot 95 degF afternoon at 5000 MSL.

Peter Duniho wrote:

"john smith" wrote in message
...
[...] Had you need to do a go
around, the cruise mixture would have been sufficient for a full power
go-around.

You do understand that he's talking about a turbocharged engine, right?
Generally speaking, full rich is the correct mixture setting for a
turbocharged piston engine, for full-power takeoffs regardless of altitude.


Yes, I remembered the turbo part this afternoon.
For descent there is no reason to change the mixture unless you are
going to push the throttle back in beyond the cruise power setting.
For takeoff, the turbo should maintain sealevel power up to 12,000 feet
MSL, so full rich or slightly leaned mixture would be used on takeoff. I
think I would still lean for best power prior to releasing brakes for
takeoff.

"john smith" wrote in message
...
[...]
For takeoff, the turbo should maintain sealevel power up to 12,000 feet
MSL, so full rich or slightly leaned mixture would be used on takeoff. I
think I would still lean for best power prior to releasing brakes for
takeoff.

You need to use full rich to keep the exhaust temperature down. With the
turbocharged engine I normally fly, in my airplane, about a third of the
fuel is used just for cooling (30 gph at full power, when theoretically only
about 20 gph would be needed for the 270 hp). The turbocharger controller
ensures that I am getting best power, without any fiddling with the mixture
at all. Even in an aircraft with a manual wastegate, one would ensure best
power using that control, not the mixture.

Pete

"Barry Klein" wrote in message
om...
We took a newer 182 turbo to a 7000' elevation airport yesterday and
the engine quit at the end of the landing roll. I'm sure the mixture
was way too rich. It restarted without incident, glad we were on the
ground!

My airplane, with a Lycoming TIO-540, will do the same thing at high
altitude airports if the mixture is set full-rich prior to touchdown.

Operationally, I simply leave the mixture alone during descent. Given that
descents are usually made at reduced power, theoretically I could even lean
the mixture during the descent (opposite of what you'd normally do with a
normally aspirated engine at power settings near cruise), but I just keep an
eye on the turbine inlet temperature and normally no change in mixture
setting is required to keep the TIT in the ballpark of 1500 F.

During a go-around, it is critical that I remember to push the mixture
full-rich, but since it is just as critical that the engine not stop until I
am actually done flying the airplane, this is an acceptable trade-off.

I also need to keep the mixture lean while taxiing, otherwise I get fouled
plugs. I asked my mechanic about both issues (since they seem related) and
he verified that the idle mixture is correct for my installation. It just
runs rich at or near idle power unless the mixture is manually adjusted. At
higher density altitudes, idle mixture is so rich it will flood the engine
and make it stop.

[...] Later that day, when taxiing for takoff, we set 1200 rpm
and leaned for peak rpm, mixture knob was out 1.5-2 inches to achieve
this.

I assume you mean you just did this as a test during taxi, and that you
returned the mixture to full rich before takeoff?

When we returned home to 800' elevation, we checked the idle speed at
full rich, it was about 500 rpm, is this too low?

Sounds about right, but I don't know the specifics for that engine. It
might be that it's supposed to be higher. I would ask the mechanic
maintaining the aircraft if he has the engine manual for the engine
installed, and then you can read in that what the actual numbers should be.

Pete

Thanks everyone for the info. This was my first flight in a turbo, my
experience is with non-turbo 182s.
My buddy was in the left seat for the landing, 6750', about 50 deg F. I'm
not sure what he did for final approach,
may have gone to full rich.

Ragards,
Barry
----- Original Message -----
From: "Peter Duniho"
Newsgroups: rec.aviation.piloting
Sent: Sunday, January 11, 2004 3:01 PM
Subject: Turbo 182: correct mixture for final approach at high altitude?


"Barry Klein" wrote in message
om...
We took a newer 182 turbo to a 7000' elevation airport yesterday and
the engine quit at the end of the landing roll. I'm sure the mixture
was way too rich. It restarted without incident, glad we were on the
ground!

My airplane, with a Lycoming TIO-540, will do the same thing at high
altitude airports if the mixture is set full-rich prior to touchdown.

Operationally, I simply leave the mixture alone during descent. Given
that
descents are usually made at reduced power, theoretically I could even
lean
the mixture during the descent (opposite of what you'd normally do with a
normally aspirated engine at power settings near cruise), but I just keep
an
eye on the turbine inlet temperature and normally no change in mixture
setting is required to keep the TIT in the ballpark of 1500 F.

During a go-around, it is critical that I remember to push the mixture
full-rich, but since it is just as critical that the engine not stop until
I
am actually done flying the airplane, this is an acceptable trade-off.

I also need to keep the mixture lean while taxiing, otherwise I get fouled
plugs. I asked my mechanic about both issues (since they seem related)
and
he verified that the idle mixture is correct for my installation. It just
runs rich at or near idle power unless the mixture is manually adjusted.
At
higher density altitudes, idle mixture is so rich it will flood the engine
and make it stop.

[...] Later that day, when taxiing for takoff, we set 1200 rpm
and leaned for peak rpm, mixture knob was out 1.5-2 inches to achieve
this.

I assume you mean you just did this as a test during taxi, and that you
returned the mixture to full rich before takeoff?

Yes, we did this just to get a smooth idle for taxi. We went full rich on
the takeoff roll and climbed out to 8500' nicely.
I just mentioned this to demonstrate how lean we needed to go to get to the
best power setting at 1200 rpm.


When we returned home to 800' elevation, we checked the idle speed at
full rich, it was about 500 rpm, is this too low?

Sounds about right, but I don't know the specifics for that engine. It
might be that it's supposed to be higher. I would ask the mechanic
maintaining the aircraft if he has the engine manual for the engine
installed, and then you can read in that what the actual numbers should
be.

Pete

is this a turbo charged engine also?
I have taken off with a DA of 8800 ft, full rich and not had a problem in my
T-arrow
I use full rich on take off and landing, as my POH says to do.

Peter Duniho wrote:
My airplane, with a Lycoming TIO-540, will do the same thing at high

altitude airports if the mixture is set full-rich prior to touchdown.

Operationally, I simply leave the mixture alone during descent. Given that
descents are usually made at reduced power, theoretically I could even lean
the mixture during the descent (opposite of what you'd normally do with a
normally aspirated engine at power settings near cruise), but I just keep an
eye on the turbine inlet temperature and normally no change in mixture
setting is required to keep the TIT in the ballpark of 1500 F.

During a go-around, it is critical that I remember to push the mixture
full-rich, but since it is just as critical that the engine not stop until I
am actually done flying the airplane, this is an acceptable trade-off.

I also need to keep the mixture lean while taxiing, otherwise I get fouled
plugs. I asked my mechanic about both issues (since they seem related) and
he verified that the idle mixture is correct for my installation. It just
runs rich at or near idle power unless the mixture is manually adjusted. At
higher density altitudes, idle mixture is so rich it will flood the engine
and make it stop.

[...] Later that day, when taxiing for takoff, we set 1200 rpm
and leaned for peak rpm, mixture knob was out 1.5-2 inches to achieve
this.

I assume you mean you just did this as a test during taxi, and that you
returned the mixture to full rich before takeoff?

When we returned home to 800' elevation, we checked the idle speed at
full rich, it was about 500 rpm, is this too low?

Sounds about right, but I don't know the specifics for that engine. It
might be that it's supposed to be higher. I would ask the mechanic
maintaining the aircraft if he has the engine manual for the engine
installed, and then you can read in that what the actual numbers should be.

Pete

"Jeff" wrote in message
...
is this a turbo charged engine also?

Is what a turbocharged engine also? Both the engine that John Smith is
talking about and the engine that I am talking about are turbocharged, as we
both stated in our posts.

I have taken off with a DA of 8800 ft, full rich and not had a problem in
my
T-arrow I use full rich on take off and landing, as my POH says to do.

Have you landed with a DA of 8800' with the mixture full rich? On my
airplane (and apparently John's), the engine would stop on rollout. That
said, maybe you have a superior fuel system on the Turbo Arrow, or perhaps
the engine is just somehow inherently more immune to overly rich mixtures.

Pete