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Rod Dynamics ?
Hello:
Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Why does it, if so ? B. |
Rod Dynamics ?
My knowledge of the actual numbers behind physics is very limited, so
I'll offer up my simple minded version of Newton's Third Law. Could it be that every action has an equal and opposite reaction? ...but I'm a designer not a physician er, physisonian, or was that a physisoligist. Oh hell I don't now what I'm talking about. -Ethan Robert11 wrote: Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Why does it, if so ? B. |
Rod Dynamics ?
On Tue, 07 Nov 2006 10:35:15 -0500, daytripper
wrote: On Tue, 7 Nov 2006 07:47:36 -0500, "Robert11" wrote: Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Why does it, if so ? B. I can't see how any downward force vectors at the rod tip increase in this scenario, so while he's correct that the rod tip will point below horizontal, it doesn't "drop", it simply lags behind the rest of the rod movement, establishing an arc... I s'pose the same thing could happen with rifles, to some (hopefully vanishingly small) degree... /daytripper I'd offer that it would be a bit difficult to hold the average fly rod "truly horizontal"...unless one just had a lesson or two and the fly rod in question was the all-new and improved O' Cedar Fishsweeper XLT1000, for which the instructor was the sole local distributor... OTOH, I'd offer that any rifle barrel that couldn't be held "truly horizontal" might make a better fly rod than rifle barrel... And finally, I'd observe that someone who suggests the physics/mechanics involved in a rifle barrel at the moment of a round's discharge are generally the same as someone lifting a fly rod would likely not know much about either...but on the plus side, they'd be readily recognized as an expert by some on ROFF... HTH, R |
Rod Dynamics ?
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Rod Dynamics ?
"Robert11" wrote in message ... Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Yes Why does it, if so ? You might be able to see it more clearly with a full-flex rod as in the case of bamboo. While holding the rod in the horizontal position, the start of the arm motion upward begins the stored energy in the rod and translates it throughout the length. Since the fly rod has a continuous taper with the thicker part at the butt and thinning as it progresses towards the tip, the upswing motion caused the tip to bend momentarily and ever so slightly downward before it begins to move and follow the rod stroke path. Not quite sure how the author relates this to rifle ballistics as you described. fwiw, -tom. |
Rod Dynamics ?
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Rod Dynamics ?
Tom Nakashima wrote: "Robert11" wrote in message ... Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Yes Why does it, if so ? You might be able to see it more clearly with a full-flex rod as in the case of bamboo. While holding the rod in the horizontal position, the start of the arm motion upward begins the stored energy in the rod and translates it throughout the length. Since the fly rod has a continuous taper with the thicker part at the butt and thinning as it progresses towards the tip, the upswing motion caused the tip to bend momentarily and ever so slightly downward before it begins to move and follow the rod stroke path. That explains nothing. Wolfgang who suspects that the downward motion is an illusion......but wouldn't be much surprised if it is in fact real. in either case, recent developments in the roffian math club suggest rather strongly that a comprehensible answer will forever remain but a dream. |
Rod Dynamics ?
On Tue, 7 Nov 2006 07:47:36 -0500, "Robert11" wrote:
Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. The moment of inertia of the tip (and every other point on the rod) coupled with the flexibly of the rod would cause the rod to flex when it was rotated, but it wouldn't cause the tip to go down - that would violate the conservation of angular momentum AFAIK. -- Charlie... http://www.chocphoto.com |
Rod Dynamics ?
On Nov 7, 6:47 am, "Robert11" wrote: Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. It *moves*, yes, and if that movement is downward, then it drops. When a rifle, or any other firearm, is fired, the barrel vibrates. The manner in which it does varies with a number of inputs -- length, heat of combustion, thickness of barrel, bedding, etc. If its bedding or stocking is such that it kicks in a certain direction, than it can be drilled near the muzzle to use escaping gasses to overcome this tendency.- He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Why does it, if so ? It does, for reasons that Tom outlined. An outdoor writer mentioned this in a magazine article LOOOOOOOONG ago (I think it was Trueblood in F&S). He was fishing for short-strike bluegills, using a vintage bamboo (read "noodle") rod. At the strike, the tip DROPPED when he pulled up. So he had to overcome natural reflex and, as he stated it, "...swat at them like swatting flies with the rod tip" to tighten the line for the strike. cheers oz |
Rod Dynamics ?
MajorOz wrote: On Nov 7, 6:47 am, "Robert11" wrote: Hello: Was reading a book on ballistics the other day, and the author was describing conditions where a rifle barrel would drop a small amount as a shell was fired. It *moves*, yes, and if that movement is downward, then it drops. When a rifle, or any other firearm, is fired, the barrel vibrates. The manner in which it does varies with a number of inputs -- length, heat of combustion, thickness of barrel, bedding, etc. If its bedding or stocking is such that it kicks in a certain direction, than it can be drilled near the muzzle to use escaping gasses to overcome this tendency.- He used an example that if one held a fly rod rod truly horiz., and gave the handle a very quick upward (I think he means backwards; toward ones head) pure rotation, the tip momentarily goes Downward. Have my rods away for the season, so can't try it. Can't visualize this happening. Does it ? Why does it, if so ? It does, for reasons that Tom outlined. An outdoor writer mentioned this in a magazine article LOOOOOOOONG ago (I think it was Trueblood in F&S). He was fishing for short-strike bluegills, using a vintage bamboo (read "noodle") rod. At the strike, the tip DROPPED when he pulled up. So he had to overcome natural reflex and, as he stated it, "...swat at them like swatting flies with the rod tip" to tighten the line for the strike. Horse****. Wolfgang |
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