Trajectory/ "LAUNCH ANGLE"

Walter & Group:

 

 

From Walter Simberski....some rather deep thoughts:-

 

 

Gordy - I was thinking along similar lines as you but then I began to think that the idea of trajectory

for fly line is too complicated. By definition, trajectory is the path of an object through space. This

is a difficult enough concept when thinking about a bullet or a space capsule but a fly line has the added

complexity that it is long, thin and very flexible. A point on the rod leg will have a different path than a

point on the fly leg and both will be different from a point on the loop - even for a "basic" cast. Change

to a curved cast, corkscrew cast, serpentine cast, one of the spey casts and it becomes difficult to

describe the path of the line and virtually impossible to find a representative point on the line to

discuss in relation to the trajectory.

 

Perhaps a slightly different approach is in order. What is the question that we are trying to answer by

defining trajectory? Are we trying to identify the variables that tell us how far a cast will travel? Are we

trying understand how the path of the hand affects the path of the rod tip, and hence, the path of the

line in order to help us explaing casting faults or specialty casts? The affect of "trajectory" on presentation?

 

My first thought when the trajectory discussion started was that it was similar to the discussion of

trajectory for bullets which is mainly concerned about the distance a bullet will travel or how much it

will drop over a given distance but may also consider how it is affected by wind or the difference between

shooting at a stationary target vs a moving one.

 

If the idea is to determine the length a cast will travel then the variables we want to look at are lift,

drag, and launch angle. Lift and drag will be determined by loop shape and orientation, wind velocity,

line shape (most lines are round but knots are a common feature that may change) line density, and line

velocity. Launch angle for a "basic" cast, i.e. slp of the rod tip has been maintained and a loop with

parallel rod and fly legs is formed, could be determined by the fly leg or the front of the loop. Rod

leg could also be used but may be inaccurate if rebound has resulted in a bit of deviation on the leg.

 

Thank

 

Walter

 

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Walter....

 

I like that term, "LAUNCH ANGLE" !

 

To simplify matters, I look at the imaginary center of the loop as the, "bullet" when I think of trajectory.  So many things can change the legs of the loop that I have not seen fit to consider those.

 

Gordy

 

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From Paul Ardin:

Hi Gordy,

yep your definition is better - thanks, I'll use this from now on.

 

Cheers, Paul