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**[email protected]** · May 20th 08, 02:35 AM posted to rec.aviation.student,rec.aviation.piloting

In rec.aviation.piloting wrote:
On May 16, 9:15 am, wrote:
In rec.aviation.piloting Mxsmanic wrote:

Is it better (in a small GA aircraft) to maintain altitude using minor changes
in pitch and trim alone, or using both pitch/trim and throttle adjustments?
I'm asking just about maintaining altitude once there, not climbing or
descending to an altitude.

Well, if you had actually read any of the books by experts you go on
about, you would know this.

Or had taken actual instruction, but I digress.

Once established in cruise and assuming power and trim have been properly
adjusted, you will in general have two factors that will cause the
altitude to change.

One is vertical wind, i.e. turbulance and thermals. This usually
requires yoke input.

The other is the airplane gets lighter as you burn off fuel. This is
what trim is for.

Theoretically the combination of temperature and pressure could cause
the engine output power to change requiring throttle and mixture
adjustments, but I don't see that happening in the typical C-172 class
flight.

--
Jim Pennino

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I find that tiny power changes work better for maintaining
altitude than fooling with small trim changes. If the airplane is
climbing a bit, cranking in nose-down trim will increase speed and
upset the whole equilibrium somewhat. If one does this to descend back
to target altitude, the extra speed obtained will be a pain to deal
with as the airplane is retrimmed nose-up to stop the descent. Speed
will bleed off and the airplane will sink below altitude. Up and down
we go. Small---really small---power changes work better.

I can see that if your throttle is capable of making tiny changes; mine
isn't.

I already replaced the mixture control with a vernier because I didn't
like the corseness of the old push-pull and one of these days I'm going
to do that to the throttle control.

--
Jim Pennino

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