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#1
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Thrust vectoring
Interesting. I can't think of too many boats that "pull" water over a
rudder for steering, except in reverse, and this is well known to be, generally, of little effect. Of course, considering the source of that statement, we realize it has no value, other than to say he didn't understand what I was saying, nor does he have any knowledge of the subject. G I'll call that a "negative", with reservations..... Come-on group, I'm looking for some pos/neg responses from people with some knowledge and experience, not jaxasses ..... otn Shen44 wrote: Subject: Thrust vectoring From: (JAXAshby) Date: 03/24/2004 19:39 Pacific Standard Time Message-id: if I told you that rudders were important tools of boat handling, but not to be considered for steering, rather for "thrust vectoring", when maneuvering around a dock, etc., when kicking an engine ahead, both positive and negative ...... would you understand what I was saying? I would know you are bull****ting, for pulling water over a rudder with a prop does not -- and can not under the laws of physics -- affect the direction a boat is moving. otn Since I know Otn has jaxass killfiled, I'll quote this nonsense so otn can read it. Shen |
#2
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Thrust vectoring
Interesting. I can't think of too many boats that "pull" water over a
rudder for steering, except in reverse, and this is well known to be, generally, of little effect. zero effect. none. |
#3
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Thrust vectoring
My first few lessons in small powerboat handling as a young lad included "thrust
vectoring" examples, although those terms were never used. I remember vividly bringing the launch (about 18 feet with an Atomic 4 and a "stick" tiller) bow to the dock and wagging the butt back and forth with the tiller. The exercise was repeated in reverse hanging off a bow line, proving (contrary to jaxie's claim) the affect works in reverse, although with greatly diminished results. These exercises were an eye-opener for me, since as a sailor, I had never thought in terms of water flow created by a prop. A few years later I had another lesson (I should have known better by then) when I tried to power off of a dock at Castine, ME with a very strong current flowing. An old hand showed me the "power against a spring line" trick. I was amazed that so much power could be brought to bear. These techniques are best taught "hands on," in a small boat, if possible, so that one can feel the power the prop can generate. Whether the words "thrust vectoring" are used depends on the audience. "otnmbrd" wrote in message hlink.net... Interesting. I can't think of too many boats that "pull" water over a rudder for steering, except in reverse, and this is well known to be, generally, of little effect. Of course, considering the source of that statement, we realize it has no value, other than to say he didn't understand what I was saying, nor does he have any knowledge of the subject. G I'll call that a "negative", with reservations..... Come-on group, I'm looking for some pos/neg responses from people with some knowledge and experience, not jaxasses ..... |
#4
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Thrust vectoring
The exercise was
repeated in reverse hanging off a bow line, proving (contrary to jaxie's claim) the affect works in reverse, geezus kriste, jeffies, you claim to have a degree in physics and have NEVER -- to this moment -- heard of classic "under water lawn sprinkler" paradox that ALL physics students learn. Get your wife to explain it to you. It is impossible to steer by *pulling* water over a rudder with a prop. Can't be done, except when under the influence of hard drugs. |
#5
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Thrust vectoring
OK, jaxie, please explain Feynman's Sprinkler Paradox and give us your answer.
And why do you think this is relevant? Are you claiming that an object placed on the "suction side" of a propeller will not feel an affect, that is it cannot be deflected to one side if it asymmetrical? "JAXAshby" wrote in message ... The exercise was repeated in reverse hanging off a bow line, proving (contrary to jaxie's claim) the affect works in reverse, geezus kriste, jeffies, you claim to have a degree in physics and have NEVER -- to this moment -- heard of classic "under water lawn sprinkler" paradox that ALL physics students learn. Get your wife to explain it to you. It is impossible to steer by *pulling* water over a rudder with a prop. Can't be done, except when under the influence of hard drugs. |
#6
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Thrust vectoring
Are you claiming that an object placed on the "suction side" of a propeller
will not feel an affect, that is it cannot be deflected to one side if it asymmetrical? yes, of course I am saying that. you would too if you had the degree in physics you claim you have. |
#7
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Thrust vectoring
an object placed on the "suction side" of a propeller
will there is no force in natural called "suction". Everyone with even one semester in physics knows that. how many semesters did you say you had, jeffies? |
#8
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Thrust vectoring
"JAXAshby" wrote in message
... an object placed on the "suction side" of a propeller will there is no force in natural called "suction". Everyone with even one semester in physics knows that. how many semesters did you say you had, jeffies? There may not be a force called "suction" but I did not use the word in that context. "Suction Side" is a commonly used engineering term, used in the context of both propellers and compressors. If you had the even most basic knowledge of refrigeration (you claimed family in the business) you would know that. You've just demonstrated that you're a complete fraud, jaxie. But we all knew that. |
#9
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Thrust vectoring
Sorry Jax, sometimes you get it right, but this time your habit of
stating absolutes where not appropriate is showing again. The underwater lawn sprinkler is an imperfect model for the mechanics of a boat's prop and rudder. Now, a prop in reverse creates very little water movement past the rudder compared to one in forward, but very little is not the same as none. As long as there is water being moving past and deflected by the rudder there will be some lateral force generated. Not much in this case, but some. This can be readily demonstrated as another poster pointed out. JAXAshby wrote: The exercise was repeated in reverse hanging off a bow line, proving (contrary to jaxie's claim) the affect works in reverse, geezus kriste, jeffies, you claim to have a degree in physics and have NEVER -- to this moment -- heard of classic "under water lawn sprinkler" paradox that ALL physics students learn. Get your wife to explain it to you. It is impossible to steer by *pulling* water over a rudder with a prop. Can't be done, except when under the influence of hard drugs. -- Dan Best - (707) 431-1662, Healdsburg, CA 95448 B-2/75 1977-1979 Tayana 37 #192, "Tricia Jean" http://rangerbest.home.comcast.net/TriciaJean.JPG |
#10
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Thrust vectoring
sorry, Dan. don't try to noodle this one out. It is a fact of physics that
you can NOT control using rudder by *pulling* water over it. you MUST push. lay people often don't that know, for intuitively it doesn't seem "right". but jeffies has in the past claimed specifically not to be a layperson regarding physics. Sorry Jax, sometimes you get it right, but this time your habit of stating absolutes where not appropriate is showing again. The underwater lawn sprinkler is an imperfect model for the mechanics of a boat's prop and rudder. Now, a prop in reverse creates very little water movement past the rudder compared to one in forward, but very little is not the same as none. As long as there is water being moving past and deflected by the rudder there will be some lateral force generated. Not much in this case, but some. This can be readily demonstrated as another poster pointed out. JAXAshby wrote: The exercise was repeated in reverse hanging off a bow line, proving (contrary to jaxie's claim) the affect works in reverse, geezus kriste, jeffies, you claim to have a degree in physics and have NEVER -- to this moment -- heard of classic "under water lawn sprinkler" paradox that ALL physics students learn. Get your wife to explain it to you. It is impossible to steer by *pulling* water over a rudder with a prop. Can't be done, except when under the influence of hard drugs. -- Dan Best - (707) 431-1662, Healdsburg, CA 95448 B-2/75 1977-1979 Tayana 37 #192, "Tricia Jean" http://rangerbest.home.comcast.net/TriciaJean.JPG |
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