Backcast loop / forward cast

Walter & Group...

[GH] Michael Heritage explains his answer on HANG TIME and gets a bit into loop dynamics "

[MH]

11. Distance casters sometimes use the term, HANG TIME. What do you think this means ?

"There is no such thing, unless someone has devised a line that defies gravity. I assume it refers to the amount of time the line remains airialised during the shoot."

Hi Gordy,

I think I should explain my answer to your question about hang time.

It might be of interest to realise that if we were to cast on a horizontal plane the line will fall to the ground in the same time frame regardless of whether we cast 30' or 130'. The only way we can influence the amount of time the line is in the air is by trajectory. There is a theory that there is some lift in a loop that counteracts gravity but that would depend on there being a loop shape that can take advantage of this. As most of us cast short to medium distances with a round loop this 'lift' can be discounted in most cases.

Mike

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[GH] Mike,

I have included a paper by physicist Noel Perkins on loop dynamics which calls attention to the drag forces on the loop and the effects of this on its fall.

The loop "lift" theories included suggestions that it might be due to airfoil effect such as that of an airplane wing. That one has been pretty well disproven, as you message suggests.

The effect of gravity will be the same with a short cast loop or a long cast loop..... just that the long cast loop is out there for a longer period of time. This is reflected in your statement on influencing the amount of time the line is in the air. In the event the trajectories for both long cast loops and short cast loops are low, then the long cast loop might well strike the ground.

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[GH] From Jim Gill :

Gordy, I've just finished studying (again) the two papers you circulated some time ago (Casting Physics Simplified - Parts 1 & 2) - regarding some of the responses below they provide more detail & understanding. "Hang" and "Pre-load " I'v never understood - regarded such terms as rather like the pleural "space" potentially there is one and when it does appear you're in trouble - I'll run with Mike Heritage and Bruce Richards.

Regards, Jim.

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[GH] Agree.

For those who have not seen these documents, I have included both Casting Physics 1 and Casting Physics 2 in attachments. Thanks to Walter Simbirski who authored each.

Walter has the wonderful capacity to make this material understood by non scientific folks !

Backcast loop / forward cast - discussion