Engine mixture guidelines

Lean the mixture until it peaks and then enrichen it
(turn it back in) until it drops 50°C.

Not necessary the best advice.

Remember FULL rich for takeoffs and landings unless your flying at
Leadville, CO or some other really high altitude airport.

That is actually VERY BAD and DANGEROUS advice! You will need to lean
for take-off at density altitudes of 3000 feet or above for max power.
Actual airport elevation is irrelevant in this discussion, density
altitude is all that matters.

--
Thomas Borchert (EDDH)

That is too much anyway, 50 C is 90 F, really 25 C is more
than enough.



"Thomas Borchert" wrote in
message ...
| Lean the mixture until it peaks and then enrichen it
| (turn it back in) until it drops 50°C.
|
| Not necessary the best advice.
|
| Remember FULL rich for takeoffs and landings unless your
flying at
| Leadville, CO or some other really high altitude
airport.
|
| That is actually VERY BAD and DANGEROUS advice! You will
need to lean
| for take-off at density altitudes of 3000 feet or above
for max power.
| Actual airport elevation is irrelevant in this discussion,
density
| altitude is all that matters.
|
| --
| Thomas Borchert (EDDH)
|

Jim,

That is too much anyway, 50 C is 90 F, really 25 C is more
than enough.


That will put you right at the point of maximum internal combustion
pressure (and mostly maximum CHT). Is that good for the engine? I doubt
it.

--
Thomas Borchert (EDDH)

What damages the engine is excess oxygen and any combustion
temperature. Any mixture with a temperature drop means that
there is excess fuel. 25 C is easy to see on the gauge and
with a single probe assures that all cylinders are rich of
peak. A multi-probe system is best as is fuel injection.

At cruise power settings, you can lean aggressively. But
only the pressure wave of detonation will damage the
combustion chamber.



--
James H. Macklin
ATP,CFI,A&P

"Thomas Borchert" wrote in
message ...
| Jim,
|
| That is too much anyway, 50 C is 90 F, really 25 C is
more
| than enough.
|
|
| That will put you right at the point of maximum internal
combustion
| pressure (and mostly maximum CHT). Is that good for the
engine? I doubt
| it.
|
| --
| Thomas Borchert (EDDH)
|

"Thomas Borchert" wrote in message
...
Lean the mixture until it peaks and then enrichen it
(turn it back in) until it drops 50°C.

Not necessary the best advice.

Remember FULL rich for takeoffs and landings unless your flying at
Leadville, CO or some other really high altitude airport.

That is actually VERY BAD and DANGEROUS advice! You will need to lean
for take-off at density altitudes of 3000 feet or above for max power.
Actual airport elevation is irrelevant in this discussion, density
altitude is all that matters.

--
Thomas Borchert (EDDH)

Ok confession time: I've never been PIC with a controllable prop.

3000 feet density altitude fits with 75% power in the POHs that I recall
reading for trainers with fixed pitch props.

OTOH, high power levels are available to a higher density altitude with a
controllable prop--consult the POH. If the POH is old, consult the engine
manufacturer.

(I really wish that I could say "consult an instructor or mechanic at the
local FBO" )

Peter

Peter,

OTOH, high power levels are available to a higher density altitude with a
controllable prop.


They are? How would that work? (flying a Tobago with CS prop)

--
Thomas Borchert (EDDH)

"Thomas Borchert" wrote in message
...
Peter,

OTOH, high power levels are available to a higher density altitude with
a
controllable prop.


They are? How would that work? (flying a Tobago with CS prop)

--
Thomas Borchert (EDDH)

Full RPM on a CS prop is usually higher than the fixed pitch prop will allow
under most conditions of flight--especially take off and climb.

Peter

Peter Dohm wrote:



3000 feet density altitude fits with 75% power in the POHs that I recall
reading for trainers with fixed pitch props.

75% is available to about 8000 feet, depends on temp.



OTOH, high power levels are available to a higher density altitude with a
controllable prop--consult the POH.

Yes, indeed, consult the POH. The prop is irrelavant to the discussion
unless you've installed one hell of a cruise prop that just won't turn up.

Mxsmanic wrote:
Up to now when flying in simulation, I've had the simulator take care
of engine mixture adjustments. However, since I'd have to do this
myself in real life, I've decided to make some modest attempts at
managing mixture myself.

Making whole-hearted attempts may prove most effective.
-----

- gpsman

gpsman writes:

Making whole-hearted attempts may prove most effective.

One step at a time.

--
Transpose mxsmanic and gmail to reach me by e-mail.