Max draw length

[Bryan Adolphe]

Jon  I got kind of the same issue going on so that’s what I’m going to do ….like Stic and Kirk mentioned …. i will tweek my form a bit just to get a bit of reflex at the end of the riser … I should be able to do that without rebuilding the form which will add a bit more preload and hopefully take a bit of stress off at the end of the riser where it meets the limb which is good.  Good luck with yours. Bryan

[Buemaker]

I do not use a wedge with a straight taper, but it dips into a concave section that starts where the limb pad ends. That way I have more meat where the limb pad ends.

[Bryan Adolphe]

I do see the advantage in that style of wedge for sure ! 

[simk]

If better string angle is the goal i put the bend more towards the inners. Am I the only one measuring string angle that way? Just my 2c

Cheers

[Jon Lipovac]

This may help me understand how guys measure this angle. Are you running a straight edge through the string groove to the throat of the riser for a reference to the string?

[Crooked Stic]

Maybe overthinking again,. I think what we want is less finger pinch. So if you got recurve or reflexed tips or tip wedges etc, keeps the string from going 90 degrees in relation to the tip you got better string angle. 

[simk]

This may help me understand how guys measure this angle. Are you running a straight edge through the string groove to the throat of the riser for a reference to the string?

You measure from the imaginary line between tips and middle of grip. Having discussed that topic with a bowyer that is physician this seems to be the only way to actually measure string angle. If on the other side you would meadure from tangent where the string lifts of from a recurve the angle is always zero, and that cannot be correct. That was his explanation and I found it logic. If you measure that way the impact of recurves on the angle is a lot smaller than you might think...but there still is an effect. However, there seems to be a lot on confusion on that topic.

[Kirkll]

You measure from the imaginary line between tips and middle of grip. Having discussed that topic with a bowyer that is physician this seems to be the only way to actually measure string angle. If on the other side you would measure from tangent where the string lifts of from a recurve the angle is always zero, and that cannot be correct. That was his explanation and I found it logic. If you measure that way the impact of recurves on the angle is a lot smaller than you might think...but there still is an effect. However, there seems to be a lot on confusion on that topic.
[/quote]

I think you’ll find that running an imaginary line from the tips to the center of the grip it is going to be a mirror image of the string itself….


You guys are making this way too complicated….. It’s the “String Angle” we are talking about here. And it’s the angle of the string itself at full draw that matters.

 The string angle on a long bow or a recurve increases as the limb tips slowly get closer together as the bow is drawn. The long bow limbs typically control that string angle with more length. So a longer draw length requires a longer bow. But…. Manipulation of where the limbs are bending, and how they are bending effects that string angle too. But long bow limbs start moving closer together much quicker than recurve limbs do…

With shorter length recurve tip limb designs. Especially static tip designs, as you start drawing the bow the limb tips go from reflexed to straight up and down and lets you draw the string further back before the tips start moving closer together.
As the string starts lifting off the back of the curl, that’s when the limbs start compressing. This is the point where your PPI starts increasing and the draw force curve starts curling upward on the graph.

There are a lot things that effect this stage in the draw a guy could devote a whole chapter in a book explaining them.  But the location of the working portion of the limb, and the length of that working portion seems to be one of the key factors, and string length, and preload determines how far you can draw the bow before the limbs start moving. Paying close attention to the first 3” of draw and getting good early draw weight plays a huge part in how that bow performs.

What I’ve always found was getting good preload with a longer string is the ticket. Staying 2.5” shorter than AMO bow length, is much higher in performance than the same limbs using a 3” under AMO length, and your string angle is better at full draw.

A lot of guys are too quick to change their limb geometry, or limb shape to increase performance and fine tune things.  Often times just changing limb pad angles, and string length can make a huge difference. And changing riser lengths can have an effect too….     

The bottom line on string angle is ….once it starts pinching your fingers you start stacking….The hell with all those other angles off the limbs.    Kirk

[simk]

[/quote]

I think you’ll find that running an imaginary line from the tips to the center of the grip it is going to be a mirror image of the string itself….

You guys are making this way too complicated….. It’s the “String Angle” we are talking about here. And it’s the angle of the string itself at full draw that matters.

[/quote]

Yes that imaginary line must mirror the string.

But the problem of stacking occurs because of changing the angle of attack at the tips.

But practically you probably very right also (-; just because of course there must be a direct relationship between all those angles in the square.

Dont wanna be dogmatic here - its just a topic i was interested for a while. Give you the original words of my bowyer physician - maybe someone finds it interesting too:

Concerning the string angle - I guess that you mean the angle between the string and the tangent of the limb at the nock, see fig. 1). If so, this angle really does not matter, or at least not as you think it would. You can imagine a small circle at the end of the limb in front of which the string is attached (at the back side). Then the angle is always zero, because the string is always tangent to the limb irrespective of the shape of the limbs (recurve, straight, etc.) and stage of drawing. Obviously this can not affect the shooting characteristics of a bow - a straight limbed bow will perform as a straight limbed bow.

What really matters is the angle between the string and the line segment connecting the middle of the bow and the point where the string is attached to (the nock), see fig 2). The shape of the force-draw curve, fig 3), is mostly determined by this angle, NOT the string angle (other quantities on which it depends include material properties etc.).

You can always approximate the limb of a bow by the line segment connecting the middle and the nock. If you recurve a bow, it acts as adding any kind of (non-contact) reflex into the bow. You pre-stress the material, which results in a force-draw curve, which is more concave, thus you store more energy in the bow (total energy is the area under this curve). This is the reason why it seems to you that low string angle "adds" energy to the bow.
From this consideration it also follows that reflexing the handle and tips has no effect when the limbs are deflexed and the overall reflex is zero. It has no advantage, except it looks fancy.
On the other hand, when you feel "stacking" it can be caused by several factors. 1) The bow is short - the angle phi in my drawing is low, so the cos(phi) gets high and the drawing force rises rapidly. This happens in short composite bows.
2) The bow is deflexed - the force-draw curve is more convex - see my drawing. This is the typical cause of stacking in longbows.
3) You push the material beyond the linear dependence of force on the strain (Hook's law) and it gets stiffer.

[Kirkll]

All I can say is Woof….that bowyer should be a politician….i see nothing helpful in anything that was written there…

It’s quite obvious this bowyer is old school and doesn’t have a lot of time into manipulating  energy storage and working limb lengths, and location of where that limb is bending in composite limb bows. Quite simply it’s the key to the whole equation.

But….. then you start looking at some of these wild horn bows, or horse bows they pull way past their ears using a thumb rings, and it just blows my mind how well they perform…. 

[Crooked Stic]

Overthinking----------