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Gyro (auto rotation) is a different case. As impossible as it may
seem, the air is going through the rotor blades OPPOSITE to the rotation you
would expect them to turn with no power applied. In my 8 years of
flying gyros I always used to look out at the blades and wonder what kept them
turning. It happens to be the same aerodynamic forces which makes a
plane glide forward with no engine. If you think about the fact that the
wings have a positive angle of attack even with no power, the plane SHOULD go
backwards.
In any case, this is completely different than a wind milling prop.
Tracy
----- Original Message -----
I'm glad I only went as far as saying they might
differ. Gyrocopters have
free-wheeling blades, they would
probably descend a 'bit' quicker if the blades
stopped
rotating.
There really are posts here which have
more useful info. I've spent a few
hours today and a couple yesterday
going thru them and capturing and organizing
info. Break-in
oils, oil-thermostats, fuel-injector stuff, soft-mounting
stock Mazda oil
coolers, MMO, A/F indicators, intake manifold lengths and
configurations,
ignition coil wire types, ... I'm actually feeling good about
being able to
have a good installation that'll work reliably despite my lack of
any
background. Something I'd like to find is 'how to remove
powder coating
from a motor'. Gold was a bad choice, I'd have less
other parts to paint if
the motor were silver and blue. I'll
probably simply repaint over the gold.
Tom
--- Bob White
<bob@bob-white.com> wrote:
> I
suspect they would be different. To hazard a guess, a free
spinning
> prop is doing less work than a prop turning a motor, so it
should
> provide less drag. But a fixed pitch prop in either condition
would want
> to turn somewhere in the range of speed you would be
gliding at. A prop
> at flat pitch would need to speed up to a
very high rpm to match the
> forward speed of the plane. If the
prop can't keep up with the forward
> speed of the plane, it will
effectively be pushing backward creating
> extra drag. At least
that's my armchair analysis.
>
> Bob White
>
> On Sun, 19 Dec 2004 18:10:25 -0800 (PST)
> Tom <tomtugan@yahoo.com> wrote:
>
> > I wonder if a free-spinning prop on a broken tranny would not
have the
> > same drag as a spinning prop which is turning the
motor? I'd be
> > inclined to say they would
differ.
> >
> > Tom
> >
> >
>
> --- Bob White <bob@bob-white.com> wrote:
> >
> > > Somenone else recently reported a spinning prop having
negligable
> > > effect on engine out glide. (Dave Leonard
maybe?). I'm thinking
> > > that the biggest effect occurs
with a C/S prop that goes to flat
> > > pitch when it looses oil
pressure. I think twins often use
> > > feathering props for
that reason.
> > >
> > > Bob White
> > >
> > > On Sun, 19 Dec 2004 15:41:53 -0500
> > > "Tracy
Crook" <lors01@msn.com> wrote:
> > >
> > > He glided about 20 miles from an altitude of only
5000 ft with the
> > > prop
> > >
freewheeling! I've heard several times that a freewheeling
prop
> > > (no engine drag on it) would generate lots of
drag. Another sacred
> > > cow shot down : )
> >
> >
> > > > Tracy
> > >
> > >
--
> > > http://www.bob-white.com
> > >
N93BD - Rotary Powered BD-4 (soon)
> > >
> > >
>> Homepage: http://www.flyrotary.com/
> >
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
> >
> >
> >
> >
> >
>
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> >
>
>
> --
> http://www.bob-white.com
> N93BD -
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>
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