Originally posted by Kirkll:
it's a total misconception that stiffer limbs are harder to change the pivot point on, or more forgiving in that regard than a floppy limb bow.
i've got a film somewhere with a couple different bows on the tiller tree cranked down to full draw, while i rotate the finger pressure on the string using a string hook 2.5" wide shaped like your fingers are at full draw..... regardless of what those limbs feel like at brace whether they are stiff, or floppy, it still takes the identical amount of pressure at full draw to rotate the grip, or the finger hook. 50 pounds is 50 pounds at full draw....
The last sentence is why I somewhat disagree with you...but I am not sure if I can clarify it perfectly on words alone.
Let's say we have two bows...and each bow is 100#@28" (just to work with a nice even number not that any of us around here would shoot that much weight).
Now, let's say bow A has a draw force curve that allows it to gain 3# per inch out to 30" and bow B is smooth to 28" but then begins to stacking and gains 4# per inch to 29" and 5# per inch at 30".
Now, let's say you put both bows in a vice and had a way to brace the riser so you could only draw ONE limb just to see the work load of the limb...and that you did this with a scale...and measured both limbs to the same flexing point necessary to produce a 26" draw (under-flexing it a lot), a 27" draw (under-flexing it slightly), a 28" draw (exactly the same as a perfectly balanced 28" draw on a strung bow), a 29" draw (over-flexing it slightly), and a 30" draw (over-flexing it a lot)...and record the weight necessary to produce that bend. We could observe and record the differences between the smooth bow and the bow that stacks. What happens to each bow when you draw with an altered pivot? With a low wrist (or visa-verse) you altered the dynamic tiller of the bow...say slightly over-flexing one limb (the lower in this case) limb to a 29" position and slightly under-flexing the other limb to perhaps the 27" position.
Bow A - the NET draw length may be near equal to the 28" balanced draw and with the smoother bow you might still get very close to 100# and you don't notice any difference in feel, even though the bow no longer has a 50/50 split...because the loss of draw weight on one limb is equally balanced by the gain on the other limb...say a 48.5/51.5 combination with the smooth draw even if the bow is out of balance.
Bow B - with the stacking bow the loss of pull weight on the less flexed 27" limb would be less than what was gained on the stacking 29" limb...perhaps only a 1/2# or some minor amount with a 48.5/52 combination resulting in a net pull of 100.5#. This is no doubt a small increase...but we are only discussing theory here anyway, but could this be enough to effect the relatively minor weight of an arrow? I think so. The increase in net pull weight with bow B I believe would seek the path of least resistance...and therefore be more prone to self-correct to obtain the balanced 100# draw where the limbs are more in time with one another. Additionally, bow B would be more prone to produce more shock (like a Hill bow) and a stack drawing feel that the archer draws it out of balance.
To illustrate this further.
Now lets say this person has BOTH low wrist with the bow hand and a hard pull with the ring finger on the drawing hand (along with a light pull of the index finger) and really exaggerates this...over-flexing the bottom limb even more so and under-flexing the upper limb even more so...
Bow A - Produces a 47.5/52.5# split (or something similar)...a net result of still 100# draw at 28" as the loss of draw weight was equally offset by the increase in draw on the over-flexed limb on the smooth drawing bow.
Bow B is produces a 48/53 balance )or something similar) due to the stacking limb gaining more than the loss on the under-flexed limb...and a net draw weight increased to 101# despite drawing the bow to the same 28" draw.
100# isn't 101#. I believe the more stable bow is likely to seek balance to have the path of least resistance for the 28" draw and would correct the pivot to the 50/50 split...and if the archer strong enough to maintain (force) the altered fulcrum that is out of balance, I believe the extra draw weight on the over-flexed limb will somewhat reduce the effect of poor timing in two ways...1. even if not eliminating the archer's error...it will reduce it, and 2. produce more acceleration on the limb that has to travel the furthest (which may help the arrow, but is likely to more shock).
That's probably as clear as mud so I tried to high light the main points. It seems to me that this reasoning would explain the exceptional stability that the HH bows are famous for. Regardless of why, what I know is HH bows are EXTREMELY resistant to torque (both vertical and lateral) and they are very stable bows. Their design is very self correcting and that is why those bows are so stable. Unfortunately, these designs are also more difficult to shoot so one ends up robbing Peter to pay Paul.
This is why finding the optimal balance of traits/attributes is important when trying to match up a given bow to a given archer...and is also why not everyone likes the same bow. We all have our own issues or lack there of...and therefore prefer different things from a bow.
Topic: Limb Stability (Read 1304 times)
