Quiz answers

Simbirski & Group....

I have taken the time to go over many answer messages.  I picked these two as "A plus" !     G.

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Answers from Tony Loader .  My comments in italics.  G. :-

Tony & Group...

A little quiz on casting mechanics :

1.)  What is meant by the term, RSP ? "Rod Straight Position"    Yes.

2.)  What happens to the fly line at RSP after the casting hand stops ? A loop forms  

Using high speed video, we tried to do as Grunde Lovolle did in identifying the single frame which showed that the loop actually began to form at RSP.  At 100 fps and even 500 fps (which his group used) we couldn't be absolutely sure that this was the case, though it was very close.  I suspect that the loop actually begins to form a fraction of a second after RSP ... but it remains for studies with faster cameras to prove that.     G.

3.)  When, during the cast, is the rod top moving at its fastest rate ? Immediately after the "Stop"commences

Yes.  Just prior to RSP.   G.

4.)  Can the fly rod bend without acceleration ? No

Correct.  The fly rod cannot bend without accelertion.  Straight line velocity won't do it.  G.

5.)  What do you think the CASTING ANALYZER actually measures ? Rate of change of rod (butt) angle

Your answer may be more correct than the one usually given, which is "angular acceleration at the rod butt".  I've wondered about that in view of the fact that acceleration is a vector quantity whereas angular change has been described as the resultant of an infinite number of vectors.  We'll need input from physicists on that one for a final answer.   G.

6.)  There are two things which must match in order to achieve an (almost) straight line path of the rod tip.  What are they ? Rod bend and casting arc    Yes.

7.)  We have been taught that when Spey casting we are no longer using the method known as "Straight Line Overhead Casting."   Is there any point when making a single spey cast when we do strive for an almost straight line path of the rod tip ? The forward cast from the "key position"   Yes.

8.)  We've been using the term, "MASS PROFILE" in describing fly lines and leaders.  What does this mean to you ? The longitudinal distribution of the line's mass.   

Yes.  Some, including Ally Gowans, feel that the term "mass profile" should be changed to mass distribution.  Below, are a couple of messages between Ally and me on that subject :

"Frankly, I prefer the term "mass distribution".  We've been using the term "mass profile" mainly because of the fact that Bruce (and others) have launched it into the fly casting lexicon.  It may be meaningless unless defined as mass distribution.  Gordy"

"Hi Gordy,

 

Mass distribution it is then! ?Mass profile? makes no sense whatever. 

Ally Gowans"

 

9.)    Do you think that both line diameter and line weight play a roll when casting on a windy day ? Yes     Agree.

10.)  Which do you think is more important when casting into a strong wind.  Line thickness or line mass distribution ? Mass distribution    Agree.

11.)  Do both stiffness and mass have an effect on leader turnover ? Yes  Agree.

12.)  If you answered "yes" to question 11.), which do you think is more important ? Mass   Agree.

13.)  What do you think actually happens when most good casters try to stop the rod  ? The rod unloads along, or very close to, the desired tip path.

Good "short answer".  Actually lots could be written on what happens.  Basically, there is no "stop" as defined by instantaneous cessation of all motion.  The stop is actually one word to describe a compendium of events dominated by rapid deceleration. (Physicists may prefer the term "negative acceleration".   G.

14.)  You are given a series of pictures of the caster and fly rod taken as multiple frames shot as the cast is made.  You are asked to pick out the one which demonstrates the point of maximum acceleration.  How do you choose it ? Look for maximum rod bend.    Yes.

15.)  Suppose you made a cast but didn't stop the rod.  Would the rod fail to unload ? No

Correct.  The rod will unload whether or not you stop it.  G.

16.)  Your student asks you, "Why do I have to make a stop at the end of my cast ?".  What do you tell him ? To form a loop.

Well.... I'd prefer, "To form an efficient loop".  (You can make a cast and slow down without ever really stopping and end up with a wide, inefficient loop.)   G. 

17.)  Now you are taking your oral Master exam.  One examiner asks this question:  "Tell us the value of making a firm stop at the end of your cast."  Your answer ? To recover and focus as much stored potential energy as possible

Good way to put it.  As I see it, the stop is needed, among other things, to provide a base or sort of platform for the rod as it unloads thus helping to maintain the path of the rod tip up to the point of loop formation.  G. 

18.)  What is the one thing a fly rod can do ? It has been said that, unaided, a rod can only unbend. Troy has said, however, that a rod can also "resist bending"

The "expected answer" = STRAIGHTEN.   However, Troy Miller is correct.  Also, it can EXIST.   The question would have been more artful if I'd said, "What is the one thing a fly rod can do on its own.     G.

19.)  Which do you think is most important for an efficient long distance cast ... the direct ("swing") effort of the caster or the unloading and release of energy from a bent fly rod ("spring") ? Swing   Agree.

20.)  You are teaching a student to cast in high winds.  He brought his 3 wt. rod rigged with a WF3F line.  For today's lesson, you have suggested he use your rod with is a 6 wt.  It is rigged with a WF6F line.  Why did you do that ? More mass therefore proportionally less wind effect .   

True .... though only part of the eqation.  That WF6S line also has smaller diameter which also helps yield less wind resistance.   G.

21.)  Which line do you think will be the best choice when casting into a strong wind with your 6 wt. fast action fly rod ?   WF6F,  DT6F, WF6I, DT6I, WF6S .. WF6S    Agree.

22.) What is the reason for your choice in 21.) ? Most favourable mass distribution and smallest diameter.

Yes.

23.)  Tell us one thing needed in order to convert rotation at the hand/cork of the fly rod to a straight line path of the rod tip ? Appropriate hand path.

Not incorrect at all.  Not the main feature, however.

I was thinking of ROD BEND.   If I try to cast with a broomstick which, for practical purposes, won't bend I cannot convert rotation at the butt into a straight line path of its tip.  G.

Gordy

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Answers from Mark Surtees :

Mark & Group...

A little quiz on casting mechanics :

1.)    What is meant by the term, RSP ?

Rod Straight Position   Yes.

2.)    What happens to the fly line at RSP after the casting hand stops ?

Exactly at RSP ? It is being propelled forwards, interesting stuff happens shortly after RSP though.. J

It may actually be true that the loop begins to form a fraction of a second after RSP !    G.

3.)    When, during the cast, is the rod top moving at its fastest rate ?

A fraction before RSP

Yes.

4.)    Can the fly rod bend without acceleration ?

No       Agree.

5.)  What do you think the CASTING ANALYZER actually measures ?

Rate of angular acceleration at the rod butt.   May be scientifically correct.  As you can see by my comments, above, I question the meaning of the term "angular acceleration".  Need some help from our physicists on that one.    G.

5.)    There are two things which must match in order to achieve an (almost) straight line path of the rod tip.  What are they ?

Casting angle, bend in the rod.    Yes.

7.)  We have been taught that when Spey casting we are no longer using the method known as "Straight Line Overhead Casting."   Is there any point when making a single spey cast when we do strive for an almost straight line path of the rod tip ?

Yes, the forward casting stroke.  Yes.

8.)  We've been using the term, "MASS PROFILE" in describing fly lines and leaders.  What does this mean to you ?

Distribution of mass through the taper of line or leader.   Yes.

9.)    Do you think that both line diameter and line weight play a roll when casting on a windy day ?

Yes.    Agree.

10.)  Which do you think is more important when casting into a strong wind.  Line thickness or line mass distribution ?

Mass Distribution    Agree.

11.)  Do both stiffness and mass have an effect on leader turnover ?

Yes    Agree.

12.)  If you answered "yes" to question 11.), which do you think is more important ?

Mass    Agree.

13.)  What do you think actually happens when most good casters try to stop the rod  ?

They don?t stop, they very rapidly decelerate, often there is a fraction of involuntary pull back.

Agree.

14.)  You are given a series of pictures of the caster and fly rod taken as multiple frames shot as the cast is made.  You are asked to pick out the one which demonstrates the point of maximum acceleration.  How do you choose it ?

Maximum rotational acceleration of the rod will be just prior to the stop position at the butt  and will most probably be the point of maximum bend, maximum acceleration of the tip/line will be just prior to RSP.

Yes.  I'd choose the frame showing the greatest rod bend.    G.

15.)  Suppose you made a cast but didn't stop the rod.  Would the rod fail to unload ?

If the rod decelerates it will unload.   Yes.

16.)  Your student asks you, "Why do I have to make a stop at the end of my cast ?".  What do you tell him ?

You will get a big baggy loop and the line will not extend forwards properly.   Agree.

17.)  Now you are taking your oral Master exam.  One examiner asks this question:  "Tell us the value of making a firm stop at the end of your cast."  Your answer ?

Because it generates an effective forward propagating loop.   Yes.  Does so, because of the resultant rod tip path.   G.

18.)  What is the one thing a fly rod can do ?

?? Not sure what you mean here Gordy, I think it can do more than one thing, It is designed to cast a fly line and to play fish, in both respects it bends.

I should have added, "on its own".   It can STRAIGHTEN.  (As Tony pointed out, Troy Miller noted that it can resist bending.)  G.

19.)  Which do you think is most important for an efficient long distance cast ... the direct ("swing") effort of the caster or the unloading and release of energy from a bent fly rod ("spring") ?

?Swing?.  Lever over Spring every time.    Agree.

20.)  You are teaching a student to cast in high winds.  He brought his 3 wt. rod rigged with a WF3F line.  For today's lesson, you have suggested he use your rod with is a 6 wt.  It is rigged with a WF6F line.  Why did you do that ?

Greater Mass in the line overall.   Yes.

21.)  Which line do you think will be the best choice when casting into a strong wind with your 6 wt. fast action fly rod ?   WF6F,  DT6F, WF6I, DT6I, WF6S ...

WF6S   Agree.

22.) What is the reason for your choice in 21.) ?

Mass is concentrated forwards, highest density line with the lowest line diameter to reduce drag.    Agree.

23.)  Tell us one thing needed in order to convert rotation at the hand/cork of the fly rod to a straight line path of the rod tip ?

Translation.    Translation will help.   We need a flexible rod to pull it off.... that's the main thing as I see it.    G.

Gordy