>To my somewhat limited knowledge of variable pitch props, you may also
>need to monitor the engine manifold pressure to keep the engine
>operating optimally especially at altitude when the mixture might be
>leaned. Too lean = bad news. How complicated this will get, I don't
>know. Variable pitch props are the start of my next set of flying
>lessons.
>
>Tony

Tony

Constant speed props do not directly or significantly affect the mixture of
the engine.

For the rest of you non-flier types..

Fixed pitch props are set to provide optimal thrust from the engine at one
condition of airspeed and engine power setting. For an example the 150
you might have trained on has a prop the is most efficient at about 95mph
in cruise or at 70 for climb. What you gain at one "setting" you loose out
at the others. If you fly from floats you want to thing to get off the
water asap
or if you do short field  you might want to climb at best rate or angle etc
while
someone else might want to go cross country and high speed or cruise is it.
The only props that are capable of doing all of them efficiently (more anyway)
is a in-flight adjustable which is the basic prop Jinx is playing with or a
constant speed
which is what he is converting it to.

There have been electrically controlled props like this since the 40's as
well as the more
common hydraulically controlled ones. The electric ones more or less use a
toggle switch
to adjust the pitch through a reversible geared electric motor. The pitch
"governor" is the nut behind
the stick aka the Pilot. They work fairly well but can bit a bit of work
when you do circuits
or "crash and dashs" as instructors call em. Where you can be playing with
the switch the entire
time. Works great however when you are going someplace.

These are not a cruise control as such but more of a rpm governor.

Dave

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