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#1
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push vs pull vis a vis rudders
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#2
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push vs pull vis a vis rudders
wayne, are you really saying that while Feynman was right regarding the forces
involved in water flow, he wasn't right when water flowed over a rudder? Interesting. Should you be able to show that you can beat sher to the next Nobel prize in physics. Hurry. Time to give it up Jax, you're busted. Fact is Feynman was right, BUT, [Sprinkler Heads] [not equal] [Rudders] Prop flow over rudder in reverse is small but it's there. |
#3
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push vs pull vis a vis rudders
Fact is Feynman was right, BUT,
Prop flow over rudder in reverse is small but it's there. nobody said there was no flow -- there is -- but it is stated that the total of the forces on the rudder are zero. that's a fact of physics. accept it or not. your choice. look like intelligent or a Luddite. your choice. |
#4
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push vs pull vis a vis rudders
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. |
#6
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push vs pull vis a vis rudders
******************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? |
#7
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push vs pull vis a vis rudders
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 |
#8
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push vs pull vis a vis rudders
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. |
#9
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push vs pull vis a vis rudders
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. |
#10
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push vs pull vis a vis rudders
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. |
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