Obviously it needs TIME to change (better correct and update) all the old fly casting knowledge.
Yes, even if it is about a very wrong concept like loading and unloading the rod being the core of fly casting.
What fly casting really is all about?
We rotate the rod in order to create the desired line speed. As a consequence the rod bends. That rod bending gives us some clear disadvantages, which we may want to learn to best deal with. The rod flexibilty (bend) also gives us some advantages, which support our fly casting in an excellent way.
What fly casting is not about?
Loading the rod first, before the rod shoots the line and fly to the target. This is not what happens! What you have to understand is, that we only store a small percentage of the energy needed for a proper cast in our rod while bending it. *
Now what are the main pros and cons of rod flexibilty/rod bend?
The main disadvantages:
One strong disadvantage of rod flexibiltity is, that casting wise the rod first bends and then it will straighten again. After straigthening the rod then will bend (over swing) into the other direction. This is what we call counterflex. The tip path during couterflex will increase the size of our loop front. The more rod bend we create, the more counterflex then opening up the loop front we will have to deal with.
The second serious disadvantage of rod bend is, that as soon as we fail to control the rotation to be smooth enough, we have a too sudden increase in rod bend causing the rod tip to dip down during it's acceleration path. What follows is called to be a tailing loop. We all know this one too well! With a non flexible rod it's nearly impossible to shape a tailing loop.
The third disadvantage of rod bend can be the time lag between the beginning of rod rotation (at the handle) and the rod tip movement. We start to rotate the rod, but it takes extra time for the tip to significantly start to accelerate, too. The more rod bend we produce, the more tip lag comes in. On long line carries this often supports the unrolled fly line to additionally start falling. The more the fly line starts to fall before it gets significant speed in launch direction, the more the line end will dangle within the next cast. This is exactly why when casting with a non flexible rod (not having any tip lag) we create a very small dangling end. The line end remains passing the caster in a more straight path. Simply timing the start of the next cast gets more critical when increasing rod bend for long carries.
The fourth disadvantage is, that when increasing rod bend the distance between the rod tip and our rod hand decreases. Thus rod rotation gets less effective in terms of creating line speed. There is a fair reason why (unless the resistance gets too high) we create more line speed with the longer rods.
The main advantages:
On the positive side the flexibilty of the rod offers us a much smoother resistance against us rotating the rod to create line speed. Imagine a non flexible rod. The moment you start to rotate the rod, the tip would start to move and thus pull the whole fly line at the same time. This means right at the start we would have to overcome the resistance offered by our fly line. Since our fly rods are flexible they start to bend at the beginning of rotation instead and thus we feel less resistance in the beginning of the cast, because the tip starts to move much slower compared to that of a non flexible rod. Fair to say rod flexibilty supports the best feel for our casting.
Another strong advantage is, that while we start to slow down the handle of the flexible rod after having hit max rotational speed (max torque), the rod starts to straighten while the rod tip still keeps accelerating. This means while we already slow down (stopp) the rod on the handle, the tip still accelerates our fly line. Compared to the non flexible rod this means we can use a longer tip path for acceleration for the same size of arc. The longer the accelerational tip path can be, the less force we need to hit the desired line speed and thus support us to control the cast. Believe me, the more force you add to your cast, the harder it gets to keep control of it!
The third big advantage of rod flexibilty is, that when using a wide arc for creating the desired line speed, rod flex helps to still move the rod tip closer to a straight path during acceleration. Fair to say rod flex supports us to use a wider arc while still matching a proper tip path during acceleration. The wider the arc for creating the desired line speed will be, the less force we can use to hit max line speed. Again this supports a better control of the whole cast. Casting a non flexible rod while using a wide arc would ask for very tricky rod hand movements (to keep proper accelerational tip path) making it hard to control the cast.
Technically speaking I should add, that a flexible rod can come in much less overall weight and a much better weight distribution (light tip section) compared to a non flexible one. Obviously we never would want to miss this advantage!
In summary I am not saying, that we don't need our fly rods to flex. As a matter of fact I have always been saying precisely the opposite!
But I recommend to focus on controlling the rotation of the rod in the first place and don't spent time thinking about the level of rod load you may or may not create as the consequence of rotating the rod!
Little bit of fly casting theory. Believe me there are much more details I could add, but I am sure you don't need to know any of them in order to understand the core of fly casting. The above though, I believe can be quite good to understand when wanting to learn to control your casting in many situations.
*The bow and arrow cast (and only this one) is working different here.
Healthy week to all of you!
All my best
Still fishing my home area...
P.s.: In the pictures below you may find the only reason why fishing-wise I truly concentrate on getting some serious bend into my rod. Here it was my friend Hansi who did it.