----- Original Message -----
From: "Tommy James" <twjames@healed.org>


> Okay, here is a real test of this groups aeronautical acumen.
>
> On the front of my Glastar is a ground adjustable Ivo Magnum (3 blade).
The
> "destructions" advise that it is adjustable from 30" to 90" pitch by
turning
> a large adjustment screw which twists a cam in each blade.  This screw has
5
> turns stop to stop, or 12" per full turn of the screw.  The prop is
> currently set at ~54" of pitch.  I ran the engine this morning to ~4500rpm
> and 25" MAP.  While there was throttle left, the engine did not seem to
want
> to advance from there.
> The plane was bouncing around like a caged animal...  This is new ( and
> exciting) to someone used to C152s.
>
> The test:
> How would one determine the correct pitch for first flight and what is the
> guesstimate of what that pitch should be?
>
> Regards,
> Tommy James<><
> ps. no further starter problem

The goal is to set the pitch where the engine will be at max recommended RPM
at WOT in level flight.   The difference between static & top speed delta
rpm works out to about 1000 engine RPM for a good fixed pitch wood prop on a
200 mph class airplane.  The delta rpm on an  IVO is a bit more than this so
you might figure on around 1200 delta.

Whatever you do, don't repeat Steve Parkman's mistake.  He pitched his prop
for maximum static thrust.  When his Long EZ reached flying speed (just
barely) the prop stopped making thrust and he wallowed around until crashing
into a cactus.  Steve is no longer among us.

Rough guess?  Id say 4700 - 5000 rpm for static.

But you need to clarify your test results a bit.  What does it mean when you
say you were at  less than full throttle "but the engine did not seem to
want to advance from there"?   Do you mean that the engine does not go
faster when the manifold pressure goes from 25" to 30"?  If so, this defies
all logic and qualifies as in the  "do not fly until solved" category.

Tracy Crook