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Coam again
Moderator: Torsten
Re: Coam again
Paul,
Exactly right. If we could reduce all the affects of drag as much as possible then there should be a significant difference in fly leg speed at the end of the cast based on the two models. Possibly casting a level sinking line (hopefully at high altitude) is what I had in the back of my mind. One of the problems is the loop. The everything gets transferred to the fly leg model without drag (I posted one above) only shows really significant difference near the end of the cast. Add air drag and the acceleration is still significant but around the point where the acceleration should be really taking off the end of the line enters the loop. In my model that doesn’t matter but in the other model I’m not sure what the people’s thoughts are about what the other model thinks because we have (I think) 2 schools of though about the loop. If it’s am is constant throughout the cast then what prevents the last bit of accelerating fly leg from physically colliding with the loop? On the other hand the idea that the am in the loop is a result of tension in the top and bottom of the loop then the loop should also accelerate appreciably but I don’t think there is consensus about the tension around the loop.
You may get to experience relativity effects in casting yet but it’s going to require a bit of practice even for you. We could attach a tiny little atomic clock to the end of your line and see if it has experienced time shift after the cast.
Exactly right. If we could reduce all the affects of drag as much as possible then there should be a significant difference in fly leg speed at the end of the cast based on the two models. Possibly casting a level sinking line (hopefully at high altitude) is what I had in the back of my mind. One of the problems is the loop. The everything gets transferred to the fly leg model without drag (I posted one above) only shows really significant difference near the end of the cast. Add air drag and the acceleration is still significant but around the point where the acceleration should be really taking off the end of the line enters the loop. In my model that doesn’t matter but in the other model I’m not sure what the people’s thoughts are about what the other model thinks because we have (I think) 2 schools of though about the loop. If it’s am is constant throughout the cast then what prevents the last bit of accelerating fly leg from physically colliding with the loop? On the other hand the idea that the am in the loop is a result of tension in the top and bottom of the loop then the loop should also accelerate appreciably but I don’t think there is consensus about the tension around the loop.
You may get to experience relativity effects in casting yet but it’s going to require a bit of practice even for you. We could attach a tiny little atomic clock to the end of your line and see if it has experienced time shift after the cast.
"There can be only one." - The Highlander.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
Re: Coam again
WalterIn my model that doesn’t matter but in the other model I’m not sure what the people’s thoughts are about what the other model thinks because we have (I think) 2 schools of though about the loop. If it’s am is constant throughout the cast then what prevents the last bit of accelerating fly leg from physically colliding with the loop? On the other hand the idea that the am in the loop is a result of tension in the top and bottom of the loop then the loop should also accelerate appreciably but I don’t think there is consensus about the tension around the loop.
As the tension changes at the top of the loop, it changes from it down to the end of the line and there is no collision in the sense where the fly leg wants to push the loop thanks to its momentum. That is a misconception which does not resists N laws. All parts of the fly leg decelerate or accelerate at the same time.
You cannot decide whether or not loop AM is constant, it comes from N laws as well. The schools you are speaking about is 1) tension at top and bottom of the loop are equal (a shortcut used in many models), or 2) one uses loop AM ODE to calculate both tensions. There is a difference in the end, the flight is faster if you use loop AM ODE. In both cases loop AM varies (increases under your no air drag assumption).
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Charles Ritz, A Flyfisher's Life
- Paul Arden
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Re: Coam again
I do notice a difference in both carry and shoot at altitude. I remember carrying the old XXD to the backing knot outside your house one year. That’s a 105’ carry and ~10’ more than at sea level for me.
Anything over about 800m I notice immediately.
Cheers, Paul
Anything over about 800m I notice immediately.
Cheers, Paul
Re: Coam again
Have you ever thrown a tail Daniel?Merlin wrote: ↑Mon Nov 06, 2023 4:01 pm
As the tension changes at the top of the loop, it changes from it down to the end of the line and there is no collision in the sense where the fly leg wants to push the loop thanks to its momentum. That is a misconception which does not resists N laws. All parts of the fly leg decelerate or accelerate at the same time.
It’s nice to see (2) becoming mainstream . It’s a sign of progress since previous discussionsYou cannot decide whether or not loop AM is constant, it comes from N laws as well. The schools you are speaking about is 1) tension at top and bottom of the loop are equal (a shortcut used in many models), or 2) one uses loop AM ODE to calculate both tensions. There is a difference in the end, the flight is faster if you use loop AM ODE. In both cases loop AM varies (increases under your no air drag assumption).
https://www.sexyloops.co.uk/theboard/vi ... 230#p45198
Vince
“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage — to move in the opposite direction.” — Ernst F. Schumacher
https://www.sexyloops.com/index.php/ps/ ... f-coaching
https://www.sexyloops.com/index.php/ps/ ... f-coaching
Re: Coam again
@Torsten,
I have found an issue with my model. As you implied I have a transformation error between two frames of reference. With the correction I am getting acceleration to infinity at the end of the cast. The issue I currently have is that my model matches the values from CoM rather than CoE. I expect I am missing something there and will continue to work at it and update if/when I make progress. Thanks for your patience.
@Paul,
Looks like we're still on for light sabers at dawn.
@ Merlin.
Cheers,
Walter
I have found an issue with my model. As you implied I have a transformation error between two frames of reference. With the correction I am getting acceleration to infinity at the end of the cast. The issue I currently have is that my model matches the values from CoM rather than CoE. I expect I am missing something there and will continue to work at it and update if/when I make progress. Thanks for your patience.
@Paul,
Looks like we're still on for light sabers at dawn.
@ Merlin.
Thanks for the good wishes, I have equations, thank you. Equations in two different frames of reference are not going to be the same but when we transform from one to the other we need to get the same results.I think you are going to hit the wall with the second model. Good luck for writing the equations, which anyway must be the same in both cases.
Cheers,
Walter
"There can be only one." - The Highlander.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
Re: Coam again
Sorry, but as one of the characters on an old time tv show used to say, "That does not compute". Can you explain it a bit more? What is the mechanism for making all of the parts of the fly leg decelerate at the same time?
fwiw, I think most people think of collisions between two objects as a physical collision between the two objects like two pool balls colliding on a table. But there doesn't need to be physical contact between the two objects. Any time two or more objects exert forces on each other for a relatively short time we have a collision. The trick is figuring out how the interaction between the two objects affects the momentum or energy of the two objects.
Thanks
"There can be only one." - The Highlander.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
Re: Coam again
Hi Walter
Unfortunately I caught covid and cannot concentrate on physics.
Merlin
Unfortunately I caught covid and cannot concentrate on physics.
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Charles Ritz, A Flyfisher's Life
- Paul Arden
- Site Admin
- Posts: 19761
- Joined: Thu Jan 03, 2013 11:20 am
- Location: Belum Rainforest
- Contact:
Re: Coam again
Hey get well soon Daniel.
Re: Coam again
I had to take a 2nd read, I thought most people would notice an 800m carryPaul Arden wrote: ↑Mon Nov 06, 2023 4:01 pm I do notice a difference in both carry and shoot at altitude. I remember carrying the old XXD to the backing knot outside your house one year. That’s a 105’ carry and ~10’ more than at sea level for me.
Anything over about 800m I notice immediately.
Get well soon Daniel, I think it's going to be a shit year for covid.
“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage — to move in the opposite direction.” — Ernst F. Schumacher
https://www.sexyloops.com/index.php/ps/ ... f-coaching
https://www.sexyloops.com/index.php/ps/ ... f-coaching
Re: Coam again
Get better Daniel!
I don’t expect casting physics will change much while you’re recovering.
I don’t expect casting physics will change much while you’re recovering.
"There can be only one." - The Highlander.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.
PS. I have a flying tank. Your argument is irrelevant.
PSS. How to generate a climbing loop through control of the casting stroke is left as a (considerable) exercise to the reader.