Planning a Trip Over The Rockies

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Learn how to quickly get best power during the takeoff roll, using
your mixture control for any higher altitude takeoffs[...]
Some use a full power runup to adjust for
max RPM before starting the roll but I always hesitated to do that to
an engine just before takeoff.

There's a good reason for doing it BEFORE starting your takeoff roll, and
frankly, adding "fiddling with the mixture" to the things a pilot has to
deal with DURING the takeoff roll seems unwise to me. Never mind the fact
that once the airplane is moving, you will have a much harder time
identifying the point at which the engine is developing maximum power, since
RPM will be increasing as the airplane accelerates.

I have no idea why you'd hesitate to do something proven to be safe, and
which is much less hazardous than your personal procedure, but I hope that
no one else applies your advice to their flights.

[...]
Having an EGT gage really helps. I think it should be mandatory on
any carburated engine but that is just the engineer in me showing I
guess....

The EGT gauge is not necessary, nor useful, for the purpose of obtaining
maximum power for takeoff. Your RPM gauge will give you a 100% reliable
indication of maximum power, since maximum power will result in maximum RPM
every time. Using the EGT gauge adds an additional layer of indirection,
and you may or may not wind up with the actual maximum power mixture setting
using it.

Pete

To each his own I guess.

I have gotten used to glancing at the EGT on my takeoff rolls just to
make sure things are feeding fuel and air, and also running right. I
look for something about 50 to 100 deg F on the rich side of peak.
EGT also tells me if I have loaded up the things with carb ice while
waiting for takeoff. It is the only cross-check that I have to figure
out if the air/fuel metering system is behaving right, and that the
engine is properly extracting energy from the combustion process.

Personally I feel that any new engine installation (such as in a
homebuilt) should have at least a temporary EGT until the
idiosyncracies (sp?) of the air intake system are proven out. I've
seen/heard of several aircraft that have been excessively lean
(especially in the winter) or rich to the point of stumbling when carb
heat is added. The technique of getting a badly iced engine back
requires aggressive leaning, but I don't see that taught anywhere.

How do you lean a constant speed prop aircraft without EGT? I agree
that leaning a fixed pitch prop on the run without an EGT is not good
practice unless you know the engine.

Maybe I am more into this because I am using autofuel.

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om...
I have gotten used to glancing at the EGT on my takeoff rolls just to
make sure things are feeding fuel and air, and also running right.

Monitoring engine gauges is fine. Trying to adjust mixture while rolling on
takeoff is not.

I look for something about 50 to 100 deg F on the rich side of peak.

Like I said, the EGT (at any time) does not give you nearly as accurate an
indication of maximum power as RPM does during a static runup. Given that
you're happy with a range of 50 degrees, that's doubly true.

EGT also tells me if I have loaded up the things with carb ice while
waiting for takeoff. It is the only cross-check that I have to figure
out if the air/fuel metering system is behaving right, and that the
engine is properly extracting energy from the combustion process.

Firstly, you can easily do that cross-check during a static full-power
run-up just before takeoff. Secondly, huh? You could easily have carb ice
and still get a normal EGT reading, albeit at a different mixture setting
than normal.

[...]
How do you lean a constant speed prop aircraft without EGT?

Funny you should ask. First of all, this thread is about a 150, and you did
mention your TriPacer as well. Both fixed-pitched props.

Secondly, during a static run-up, even a constant speed prop is usually
going to be able to show you maximum power. Keep the prop control to
maximum RPM and for most installations, there won't be enough engine power
to bring the prop to the actual maximum RPM. This is true even at sea
level, but especially true if you're at high density altitude (the situation
we're talking about here), even for higher-powered engines.

I agree
that leaning a fixed pitch prop on the run without an EGT is not good
practice unless you know the engine.

I don't think that adjusting the mixture during the takeoff roll is a good
practice under any circumstance. The takeoff roll is a time during which
you should be trying to minimize workload, not introducing new, optional
items to add to your workload.

On top of everything else, it's my personal practice to keep my hand on the
throttle throughout the takeoff. This is a common technique used by many
pilots and helps ensure that the throttle doesn't accidently vibrate off the
full-power setting, and of course in a twin, makes sure your hands are in
the right place in case of an engine failure below Vmc (in airplanes where
that's an issue). It would be hard to keep one's hand on the throttle at
the same time you're fiddling with the mixture.

Maybe I am more into this because I am using autofuel.

I don't see what the type of fuel has to do with it.

Pete

Around here (Western Canada) most of the neophytes who get into
trouble in the mountains crash because of weather considerations or by
entering an upsloping valley that the airplane can't outclimb and the
pilot waits too long before turning around.
Mountain weather is treacherous and can change very rapidly. Pay
attention to the weather briefers. Mountain clouds usually have rocks
in them.
Mountain valleys can be confusing, especially if there's no
highway to follow, and it's easy to turn into a wrong canyon and get
lost real quick. The route should be marked on the map, with compass
headings penciled in on each leg. For anemic airplanes like the 150,
wind direction over the hills can make the difference between climbing
and sinking, as can lift or sink generated by solar heating or shade
on the slopes.

Dan