"Pete Brown" wrote in message ...

If a conventional aircraft is in stable level flight and the stick is
pulled back, all of the texts I have read indicate that the aircraft
pitches up, rotating through the CG.


It rotates around the CG, not through it.


Is this exactly correct or is it a very useful approximation good for
all practical purposes?

Most aircraft have the CG located slightly forward of the center of
pressure ( CP or center of lift) for positive pitch stability. I was
wondering if the actual point of rotation is displaced somewhat aft of
the CG, someplace close to the CG but in fact some small distance
towards the CP.

When the aircraft is subject only to the force of gravity, any
displacement will cause it to rotate around the cg but in flight its
subject to gravity as well as the aerodynamic forces which act through
the CP, suggesting to me that the point of rotation is not quite on the CG.



Thanks

--
Peter D. Brown
http://home.gci.net/~pdb/
http://groups.yahoo.com/group/akmtnsoaring/


Going home after a long day
http://farm2.static.flickr.com/1415/...22928754_b.jpg

The fleet at Summit. Mt. McKinley is about 45nm away at 20,320 msl.
http://farm1.static.flickr.com/187/4...cb8d2482_b.jpg

The 170B at Bold near Eklutna Glacier
http://farm1.static.flickr.com/168/4...a216d7bb75.jpg