May 29th 16, 12:52 AM
On Thursday, May 6, 1999 at 12:00:00 AM UTC-7, Steven Estergreen wrote:
> Point taken, although I apparently didn't write precisely enough, either. What I
> meant was that the "rolling moment" didn't produce a rolling motion of the aircraft.
> Thinking it over, I guess the more usual term for a moment that produces a rolling
> movement of the aircraft is "roll moment," as compared to a "yaw moment" or "pitch
> moment." And "rolling moment" could be interpreted more generally, as a moment that
> is produced by a force that is constant in direction, but rotating at some radius
> from the coordinate system of interest. It wouldn't necessarily, but could, relate to
> aircraft. That appears to be what you meant.
>
> highflyer wrote:
>
> > Steven Estergreen wrote:
> > >
> > > Actually, rather than a rolling moment, the one bladed prop would cause
> > > alternating pitch and yaw. The asymmetric force rotates around the longitudinal
> > > axis of the aircraft, but is aligned with it. So any moment produced acts about
> > > the pitch or yaw axis, and would not produce the motion commonly referred to as
> > > "rolling", rotation about the longitudinal axis.
> > > Yeah, I know, semantics....
> > >
> > >
> >
> > Semantics indeed Steve. That IS a "rolling moment about the hub"
> > which is, of course, rotating. Therefore the rolling moment about
> > the hub is felt by the airframe as a moment in constantly changing
> > directions, but always away from the single blade. It doesn't do
> > any good to write precisely when you don't read with equal precision!
> > <g>
> >
> > HF
EVEREL! check out everel props used on early piper cubs one blade high performance, smooth at all speeds. don't let the engineers discourage you. i find engineers are confused by their own brilliance.
> Point taken, although I apparently didn't write precisely enough, either. What I
> meant was that the "rolling moment" didn't produce a rolling motion of the aircraft.
> Thinking it over, I guess the more usual term for a moment that produces a rolling
> movement of the aircraft is "roll moment," as compared to a "yaw moment" or "pitch
> moment." And "rolling moment" could be interpreted more generally, as a moment that
> is produced by a force that is constant in direction, but rotating at some radius
> from the coordinate system of interest. It wouldn't necessarily, but could, relate to
> aircraft. That appears to be what you meant.
>
> highflyer wrote:
>
> > Steven Estergreen wrote:
> > >
> > > Actually, rather than a rolling moment, the one bladed prop would cause
> > > alternating pitch and yaw. The asymmetric force rotates around the longitudinal
> > > axis of the aircraft, but is aligned with it. So any moment produced acts about
> > > the pitch or yaw axis, and would not produce the motion commonly referred to as
> > > "rolling", rotation about the longitudinal axis.
> > > Yeah, I know, semantics....
> > >
> > >
> >
> > Semantics indeed Steve. That IS a "rolling moment about the hub"
> > which is, of course, rotating. Therefore the rolling moment about
> > the hub is felt by the airframe as a moment in constantly changing
> > directions, but always away from the single blade. It doesn't do
> > any good to write precisely when you don't read with equal precision!
> > <g>
> >
> > HF
EVEREL! check out everel props used on early piper cubs one blade high performance, smooth at all speeds. don't let the engineers discourage you. i find engineers are confused by their own brilliance.