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Discussion Starter · #1 ·
why tip defection doesnt quite work as a means to bow stability.
take a longbow. the tip and the string are attached directly. so any tip movement is related to string movement.
in a recurve where the recurve portion is both short and pointing upright and close to the string in a vertical looking down axis then the tip movement is related to string movement.

if the tip is 6" away from the unsupported string. then the tip can show rotational movements that dont effect the strings position



so looking at tip movement is not a direct reflection on bow accuracy.

there is more to this post but one step at a time
 

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Discussion Starter · #2 ·
lets use a spring diving board as an example.
attach the string to the end of the board and the movement at the end is directly the movement you will get on the string.

attach a string half way between the base of the board and the end. and the movement at the end of the board is indicative of the string movement. but not directly the movement.

attach the sstring to the base of the board and the movement of the end of the board is irrelevant to the string. the distance that the movement is off axis to the unsupported the more irrelevant it becomes
 

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This is perhaps an oversimplification . . . but . . . to me the question is this:

Is the tail (the limb's tip) wagging the dog (string and ultimately, bow), or is the dog (the string and /or bow) wagging its tail (the limb's tip)?

If the dog is wagging its tail overmuch I might first be looking at my form and especially release.

If the tail is wagging the dog, I might first be looking at how I have tuned the bow. The basics; brace height, nocking point, tiller, plunger or sideplate offset.

If I am confident my form and release are good, and the bow's tuning is good then I might look for anomalies in the limbs, be it manufacturing defect or a deficiency in design.

Regards,

Salskov
 

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Discussion Starter · #4 ·
yes id say so too. but that is not my point for this thread.
my point is that if the unsupported part of the string is not directly connected to the part thats moving. then the movement in the moving part is not relevant

This is perhaps an oversimplification . . . but . . . to me the question is this:

Is the tail (the limb's tip) wagging the dog (string and ultimately, bow), or is the dog (the string and /or bow) wagging its tail (the limb's tip)?

If the dog is wagging its tail overmuch I might first be looking at my form and especially release.

If the tail is wagging the dog, I might first be looking at how I have tuned the bow. The basics; brace height, nocking point, tiller, plunger or sideplate offset.

If I am confident my form and release are good, and the bow's tuning is good then I might look for anomalies in the limbs, be it manufacturing defect or a deficiency in design.

Regards,

Salskov
 

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If the dog is wagging its tail overmuch I might first be looking at my form and especially release.
I like your analogy.

I was under the impression that the search for increased torsional stability was at least in part an attempt to calm unruly dogs.

Is that not the supposed benefit? To help override form errors, or at least be more forgiving of them?
 

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if the tip is 6" away from the unsupported string. then the tip can show rotational movements that dont effect the strings position

so looking at tip movement is not a direct reflection on bow accuracy.
I think I understand and agree, as long as any tip movement only happens after the arrow is gone, and the unsupported part of the string is as you describe. However, at the moment of release, (full draw) the unsupported part of the string is much more like that of a longbow at brace, and fully susceptible to any movement of the tip.
 

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If you twist the tip does the rest of the limb not show some (although small) deflection?
 

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Discussion Starter · #8 ·
If you twist the tip does the rest of the limb not show some (although small) deflection?
yes. the twist is coming from the tip. rather than the tip being the loose end.

the problem is that high speed filming comes with several problem. software driven high speed is often interpolated. so every other frame is madeup.
real slow mo is filed as a individual frame. this means the movement seen is real.
the second problem is the speed at which the cmos or ccd sensor can relay the data to the memory. there is some funky info on how the systems manifest the issues. such as wiggly bow strings mid shot.
the pixels are normally read top left to bottom right.
this means uf the action is at the same speed as the image is being recorded you end up with a funny strobe effect/ time delay from top of shot to bottom.
turning the camera 90 degs gives a very different effect of what is the same deal.
this isnt a problem with interpolated video.
since the frame rate isnt really there in the first place.
for example lets say a shot takes place over a 0.3 of a second.
most mobiles record at 30fps. meaning you get what. 10 frames over the whole power stroke.
thats tough going to see even smaller frequencies within that time frame.

anyhow.
i think an understanding of the types of movement and sources of energies that cause the mivement would help.
so lets see if we can list them?
 

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Discussion Starter · #9 ·
you have linear
and rotational.

tip movement can be symetrical (both tips at the same time) and asymetrical.

and tip movement can be up and down
back and forth
left and right.
 

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Discussion Starter · #10 ·
if limb timing is good. the movement will be symetrical.
symetrical movement comes from a central source such as string follow through. providing the two limbshave closure at the same position and time during the power stroke.
this can show on a longbow as a vertical movement of the tip.

it can also be a down ward motion on a convetional recurve. as the tips/ string wrap and limb are all in the same line.

if the tips and string wrap are not in the same line as the string follow through the movement will be different.

but since the movement comes from the same central symetrical source the NP shouldnt devate from its central path.
 

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So...if I am understanding this..

If both tips are symmetrical in their movement. .everything is working properly and the accuracy won't be impeded. ...then whatever movement after the arrows are off the string is ilrelivent unless damage is occurring to the limb...or correct?

What about the out of phase vibrations...is string walking going to amplify these to a point of distraction?

Mac
 

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Is this about the new Hex limb tip movement after the shot on slow motion? The reason it does that is obvious to me, the curl is well past the line of force from the string at bh. I see no affect from this during the shot, I only asked JP if he could feel it. I say this has no affect on the accuracy, cause from BH to anchor, as the limb tip uncurls, it becomes more supported by the string. The more those tips uncurl, the stronger they become. In my opinion what Sid(s) need to worry about is if the unsupported limb tip shows any side to side motion, or a serious torque shooter flipping the limb around and unstringing itself. Maybe this cant happen, but my gut says the further the curl is the more likely it could happen. Maybe Hex 7 isnt even close to that point, I dont know.
 
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Discussion Starter · #13 ·
string walking is a controled environment.
and still subject to release variables.

a bow that is vertically stiff to move appears to be more forgiving of vertical timing issues.
all target bows are that way. not all hunting/field bows are vertically as hard to challenge.

but yes. if there is asymetry between the limbs then the np will be prone to vertical movements at the point of separation.

try it with a braced bow and a bow square on it and push the top limb forward.
do this with both limbs equally.
now imagine a asymetrical string follow through
 

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Discussion Starter · #14 ·
Is this about the new Hex limb tip movement after the shot on slow motion? The reason it does that is obvious to me, the curl is well past the line of force from the string at bh. I see no affect from this during the shot, I only asked JP if he could feel it. I say this has no affect on the accuracy, cause from BH to anchor, as the limb tip uncurls, it becomes more supported by the string. The more those tips uncurl, the stronger they become. In my opinion what Sid(s) need to worry about is if the unsupported limb tip shows any side to side motion, or a serious torque shooter flipping the limb around and unstringing itself. Maybe this cant happen, but my gut says the further the curl is the more likely it could happen. Maybe Hex 7 isnt even close to that point, I dont know.
yes google compound cam derailments.

so yes.

we have increased the riser deflex. which increases the stability too.
more reflexed risers have more limb movement so more speed.
we backed off the speed for stability in the draw and in the power stroke.
the TS of this laminate is greater than the BB2.

just like compounds struggle with cam lean. we have had to work hard with bow hand torque.

so in short if you can make a bow unstable. you can therfor make it stable.
so we have used the stable features to an extra amount as you can see in the riser shape to make a bow with unique features
 

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yes google compound cam derailments.

so yes.

we have increased the riser deflex. which increases the stability too.
more reflexed risers have more limb movement so more speed.
we backed off the speed for stability in the draw and in the power stroke.
the TS of this laminate is greater than the BB2.

just like compounds struggle with cam lean. we have had to work hard with bow hand torque.

so in short if you can make a bow unstable. you can therfor make it stable.
so we have used the stable features to an extra amount as you can see in the riser shape to make a bow with unique features
This is why you are doing the BD riser/hex 7 and not ILF just yet? In my opinion you guys have it under control and its a non issue. :cheers:
 

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Discussion Starter · #16 ·
the lateral string movement is minimal.
for example. how many of you can just pick up a bow and shoot it with a 6.5" brace. without an arm guard.
both Ray and Joe did it in thier video.
not one winced with that well know sting we all know.
even with sleeves on.
 

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Discussion Starter · #17 ·
This is why you are doing the BD riser/hex 7 and not ILF just yet? In my opinion you guys have it under control and its a non issue. :cheers:
the ILF platform has issues for this design. and its a lack of deflex in some designs.
the 17" DAS Riser has good deflex. but we are scared of risers like the TAC. and other wooden inline risers out there.
 

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Discussion Starter · #18 ·
asymetrical "limb flap" as its called is a problem for efficency.

that said. what other bow can get close to 200fps with 10gpp at 28" finger shot
 

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Hmmm...they say a picture is worth 1,000 words...



And I also couldn't help but notice that CAT40 tool holder in Sids avatar...as I've been an all around machinist for the past 3 decades in the aerospace industry...and mostly the non-commercial R&D end of things...where for the past decade I've been modeling, programming, setting up and running two (2) 3D CNC milling centers for the past 8 years....everyday...and what I see in that pic above?...is that even though the string appears to be in an extremely slack condition?...the oscillations are by and in large primarily in the Y axis...(for/aft)...with nearly zero detectable deviation in the X axis...(sideways)....however...this is a "still shot"....and it would take far more than one still photo and some very expensive equipment to ascertain the amount of X axis sideways motion as it relates to the forward motion of the limb tips as the string runs it's path...but to me?...despite any variations between the limb tip paths and the string path?...the strings path is the strings path. (that would be a period)

and what I mean by that is this....as the other obvious and notable factoid in the above pic is the fact that Elvis (the arrow) has left the building....but before it did?...that string was loaded down with the mission of propelling hundreds of grains of mass at a high rate of speed....during which time?...I suspect there was very little (if any) slack in that string...and even if the limb tips and the string didn't share exactly the same exact path of travel?...(which I doubt any bow does since there's no such thing as "Perfect" in this world)...I have a high level of trust that the archer in that picture had his plunger/rest very well tuned to compensate for just that...much like we build out strike plates or select particular diameter shafting to tune that very condition out of our imperfect off-the-shelf bows.

In closing (because I think my 1,000 words are just about up! LOL!)...I have 3 things I'd like to end with...

1. I once owned an shot a 21st Century Carbon Edge longbow that was a visual nightmare looking down the limbs...but the bow shot lights out...and if I didn't have personal issues with the poundage and the grip the bow would still be mine.

2. There's a thread in another website I visit entitled "The Traveling Polar Bear"....where the owner of this bow graciously offered for others to start a list of who would get the bow next to shoot it for a month then send it to the next person on the list...the bow has more vertical cracks than I care to count and a severe twist to the upper limb tip and thus far?...the owner and everyone who's received it claims the bow shoots lights out and are amazed at it's consistent level of accuracy. (I suspect it's in the tuning)

and finally?...

3. "Gary Davis": Here's a man who's a dedicated self-bow shooter...who loves fashioning his non-laminated, just wood bows from the most crooked staves he can find...then stands at 40yds and puts his wood shaft arrows in a softball sized group.

Just some food for thought in this smorgasbord of pontification regarding "after-the-fact" limb tip reaction.

and now?...it's time for me to "Make The VAP's"....the ones that shoot like lasers off my 1/2 century old Bear Polar! :lol:

L8R, Bill. ;)
 

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Discussion Starter · #20 ·
Hmmm...they say a picture is worth 1,000 words...



And I also couldn't help but notice that CAT40 tool holder in Sids avatar...as I've been an all around machinist for the past 3 decades in the aerospace industry...and mostly the non-commercial R&D end of things...where for the past decade I've been modeling, programming, setting up and running two (2) 3D CNC milling centers for the past 8 years....everyday...and what I see in that pic above?...is that even though the string appears to be in an extremely slack condition?...the oscillations are by and in large primarily in the Y axis...(for/aft)...with nearly zero detectable deviation in the X axis...(sideways)....however...this is a "still shot"....and it would take far more than one still photo and some very expensive equipment to ascertain the amount of X axis sideways motion as it relates to the forward motion of the limb tips as the string runs it's path...but to me?...despite any variations between the limb tip paths and the string path?...the strings path is the strings path. (that would be a period)

and what I mean by that is this....as the other obvious and notable factoid in the above pic is the fact that Elvis (the arrow) has left the building....but before it did?...that string was loaded down with the mission of propelling hundreds of grains of mass at a high rate of speed....during which time?...I suspect there was very little (if any) slack in that string...and even if the limb tips and the string didn't share exactly the same exact path of travel?...(which I doubt any bow does since there's no such thing as "Perfect" in this world)...I have a high level of trust that the archer in that picture had his plunger/rest very well tuned to compensate for just that...much like we build out strike plates or select particular diameter shafting to tune that very condition out of our imperfect off-the-shelf bows.

In closing (because I think my 1,000 words are just about up! LOL!)...I have 3 things I'd like to end with...

1. I once owned an shot a 21st Century Carbon Edge longbow that was a visual nightmare looking down the limbs...but the bow shot lights out...and if I didn't have personal issues with the poundage and the grip the bow would still be mine.

2. There's a thread in another website I visit entitled "The Traveling Polar Bear"....where the owner of this bow graciously offered for others to start a list of who would get the bow next to shoot it for a month then send it to the next person on the list...the bow has more vertical cracks than I care to count and a severe twist to the upper limb tip and thus far?...the owner and everyone who's received it claims the bow shoots lights out and are amazed at it's consistent level of accuracy. (I suspect it's in the tuning)

and finally?...

3. "Gary Davis": Here's a man who's a dedicated self-bow shooter...who loves fashioning his non-laminated, just wood bows from the most crooked staves he can find...then stands at 40yds and puts his wood shaft arrows in a softball sized group.

Just some food for thought in this smorgasbord of pontification regarding "after-the-fact" limb tip reaction.

and now?...it's time for me to "Make The VAP's"....the ones that shoot like lasers off my 1/2 century old Bear Polar! :lol:

L8R, Bill. ;)
Watch these vids


Its called the rolling shutter effect.

Its an illusion...
 
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