where does the model roll?

[Bob Kane]

There is another center, the center of pressure. The
model would rotate on a point somewhere between the
center of gravity and the center of pressure. I would
surmize the designs of current pattern plane designs
tend to put the vertical position of the center of
pressure and the center of gravity at the same point.
A trainer design would put the vertical center of
pressure above the center of gravity so the plane
would have a natural tendency to fly upright.


--- Bill Glaze <billglaze at triad.rr.com> wrote:
> Jim:
> True.  The C.G. is much more than the common point
> we use to balance our
> aircraft.  It is actually, as I'm sure you know, a
> point in space that is,
> generally, depending on design, not reachable by
> normal means.  On most
> "normal' configuration of monoplanes, somewhere
> inside the fuselage.  Rotation
> is considered to be about this point.
> 
> Bill Glaze
> 
> 
> JOddino wrote:
> 
> > ----- Original Message -----
> > From: "Koenig, Tom" <Tom.Koenig at actewagl.com.au>
> > To: "'Discussion'" <discussion at nsrca.org>
> > Sent: Wednesday, January 08, 2003 3:31 PM
> > Subject: where does the model roll?
> >
> > > Hi Guys,
> > >
> > > I've just been asked this question.........it
> never occurred to me to
> > really
> > > think about this, now I'm open to opinions,
> facts and anyone that has the
> > > cold hard knowledge.
> > >
> > > I have always assumed that a model rolls around
> the datum line ie: the
> > > crankshaft center line (not taking down and side
> thrust into
> > consideration)
> > >
> > > Now a mate of mine swears black and blue that in
> actual fact the model
> > rolls
> > > around the wing center line ie: it is the wing
> that rolls and all else
> > > scribes an arc around this.
> > >
> > > Can anyone can set us straight......please?
> > >
> > > Thanks
> > >
> > > Tom
> > >
> > I'll say it rolls around the cg but how many of
> you know where the cg is
> > along the vertical axis?
> >
> > Jim
> >
> > =====================================
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> > #
> 
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> 


=====
Bob Kane
getterflash at yahoo.com

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