It exerts a force against the rudder,

why is that? Please explain in detail, as the physicists disagree with you.
If you are right, you stand to make a fortune on the Nobel prize money alone.

On 29 Mar 2004 03:27:38 GMT, (JAXAshby) wrote:

It exerts a force against the rudder,

why is that? Please explain in detail, as the physicists disagree with you.
If you are right, you stand to make a fortune on the Nobel prize money alone.

================================================== ==

If flow deflection takes place (rudder at angle to flow), a force is
exerted. Old news to everyone, Nobel prize not likely.

******************If****************** flow deflection takes place (rudder at
angle to flow), a force is
exerted.

*IF* is the operative word. The question is why do *you* believe there is
deflection? The physicists don't believe that. Why do you?

Wayne.B wrote in message
...
On 29 Mar 2004 03:27:38 GMT, (JAXAshby) wrote:

It exerts a force against the rudder,

why is that? Please explain in detail, as the physicists
disagree with you.
If you are right, you stand to make a fortune on the Nobel
prize money alone.

================================================== ==

If flow deflection takes place (rudder at angle to flow), a
force is
exerted. Old news to everyone, Nobel prize not likely.

Wayne,

I can imagine a description of flow over the rudder which would
meet Jax's flat (and rather unhelpful) statements, and also
square with the obvious deflection that must occur just before
entering the prop. Whether it's realistic or not is another
matter.

Perhaps water approaches the propeller via the deflected rudder
through an Ess bend. ie, water approaches a point about a third
of the way from the tip of the deflected rudder (lets call it the
stagnation point). From one side of this point, water idles off
at a steep angle to round the rudder tip, doing a hairpin bend to
run back to the prop. From the other side the water moves quickly
along the rudder surface to the prop.

Well, it's a thought. I'm off to play with bits of card and wire
to repeat Derek Rowells experiment, so perhaps I should add a few
burning fag ends to the picture?

JimB

Wayne.B wrote:

Take a look at flow patterns through props some time. You're
assuming that all the flow past the rudder (when on the suction
side) is parallel to the keel (center) line, as it *basically* is
on the discharge side.

The intake side of the prop, however, has a cone-shaped intake
pattern, with the prop at the apex. If the rudder is at an angle
to the centerline, flow will take the path of least resistance,
and to the extent that there is impact pressure on the rudder side
with the highest aspect ratio, this will just cause
disproportionate flow around the other side, increasing impact
pressure on that side, until an equilibrium is reached. Once past
the rudder, the flow resumes its 'along the centerline' flow, so
there is no net deflection, and all 'thrust' is parallel to the
centerline.

Keith Hughes

If flow deflection takes place (rudder at angle to flow), a force is
exerted. Old news to everyone, Nobel prize not likely.

nice, Keith.

Wayne.B wrote:

Take a look at flow patterns through props some time. You're
assuming that all the flow past the rudder (when on the suction
side) is parallel to the keel (center) line, as it *basically* is
on the discharge side.

The intake side of the prop, however, has a cone-shaped intake
pattern, with the prop at the apex. If the rudder is at an angle
to the centerline, flow will take the path of least resistance,
and to the extent that there is impact pressure on the rudder side
with the highest aspect ratio, this will just cause
disproportionate flow around the other side, increasing impact
pressure on that side, until an equilibrium is reached. Once past
the rudder, the flow resumes its 'along the centerline' flow, so
there is no net deflection, and all 'thrust' is parallel to the
centerline.

Keith Hughes

If flow deflection takes place (rudder at angle to flow), a force is
exerted. Old news to everyone, Nobel prize not likely.

On Mon, 29 Mar 2004 08:59:59 -0700, Keith Hughes
wrote:
this will just cause
disproportionate flow around the other side, increasing impact
pressure on that side, until an equilibrium is reached. Once past
the rudder, the flow resumes its 'along the centerline' flow, so
there is no net deflection, and all 'thrust' is parallel to the
centerline.

======================================

Point taken and understood. I was assuming a starting condition with
the rudder parallel to an established flow, and then turned at an
angle causing a deflection and small side force. Given the general
weakness of the flow and somewhat unfocused direction, it's quite
believable that an equilibrium could be reached. Until that happens
I'm still convinced that a small amount of deflection and force would
be produced, similar to what the good professor at MIT observed with
his fan.

similar to what the good professor at MIT observed with
his fan.

what the "good professor at MIT observed" was that starting with an an empty
tube there was a tiny movement until the tube filled.

wayne, you may have noticed in your travels that water surrounds a boat in the
water, so there is no waiting for the tube to fill.

you are trying to salavage an untenable position.

JAXAshby wrote in message
...
similar to what the good professor at MIT observed with
his fan.

what the "good professor at MIT observed" was that starting
with an an empty
tube there was a tiny movement until the tube filled.


I seem to remember you damned the professor for using a metaphor
.. . .

JimB

he is a yo-yo.

candidly, when I first saw his post and noted his email address, I figured some
yo-yo hijacked his address. He claimed professional expertise in fluid flow,
but his website make no mention of such, though it does promote his "expertise"
in control systems for things such as MRI's.

similar to what the good professor at MIT observed with
his fan.

what the "good professor at MIT observed" was that starting
with an an empty
tube there was a tiny movement until the tube filled.


I seem to remember you damned the professor for using a metaphor
. . .

JimB