Author Topic: Stacking  (Read 5557 times)

0 Members and 1 Guest are viewing this topic.

mikekeswick

  • Guest
Re: Stacking
« Reply #15 on: July 20, 2015, 02:49:56 am »
Look at the bigger picture.
Angle in the string where you pull from and the angle at the tips are both important factors.

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: Stacking
« Reply #16 on: July 20, 2015, 04:06:38 am »
Here's my hypothetical bow.
Its drawn perfectly symmetrically except one limb is shaped slightly differently over the last few inches, but the nock position at brace and full draw is identical (btw it shoots real smooth ::)).
Is the string angle actually any different for each limb assuming the limbs flex over the same length?
Is the string angle the actual tip angle or the angle from string to a point midway down the limb?
Note the angle of string at the fingers is the same either side (assuming bow held dead centre, arrow shoots from dead centre for simplicity)
Del
Health warning, these posts may contain traces of nut.

blackhawk

  • Guest
Re: Stacking
« Reply #17 on: July 20, 2015, 08:51:19 am »
@Del....ya gotta  huge hinge on the left limb of your bow.  :laugh:

Offline George Tsoukalas

  • Member
  • Posts: 9,425
    • Traditional and Primitive Archers
Re: Stacking
« Reply #18 on: July 20, 2015, 09:21:38 am »
"Is the string angle the actual tip angle or the angle from string to a point midway down the limb?"

Tip angle.

Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline PatM

  • Member
  • Posts: 6,737
Re: Stacking
« Reply #19 on: July 20, 2015, 11:04:57 am »
Del, you can see that you can't draw an ellipse and put a recurve on one side. The  increased bend on the recurved side would change the whole limb. That's why you had to throw the hinge in there to get everything lined up

Offline DC

  • Member
  • Posts: 10,396
Re: Stacking
« Reply #20 on: July 20, 2015, 12:05:53 pm »
So in Del's picture the right limb would stack before the left?

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: Stacking
« Reply #21 on: July 20, 2015, 01:17:27 pm »
OK...
So if we now assume both limbs are totally static for the last section (up to and including the hinge) as shown in the new pic'.
They both now have identical 'working limb' length.
Does the silly shaped lever behave any different to the slightly deflexed shaped lever?
Is the actual string angles the same on each?

I'm playing Devil's advocate to some extent here... As PatM points out if I add the recurve without the hinge (dotted line) I'm increasing string length, which changes the geometry . I'm just striving for better understanding of cause and effect really.
Del
« Last Edit: July 20, 2015, 01:27:31 pm by Del the cat »
Health warning, these posts may contain traces of nut.

Offline George Tsoukalas

  • Member
  • Posts: 9,425
    • Traditional and Primitive Archers
Re: Stacking
« Reply #22 on: July 20, 2015, 06:49:30 pm »
"So in Del's picture the right limb would stack before the left?"
Correct.

All bows stack potentially, Del, the limb on the right would, way before the one on the left.

You lost me on the rest of your last post LOL. Spent a good part of the day in 90 deg F temps.

Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline jeffp51

  • Member
  • Posts: 1,641
Re: Stacking
« Reply #23 on: July 20, 2015, 06:52:24 pm »
I think stack is really just simple geometry.  the tip moves in an arc--and has a backward component and a downward component. Only the backward component results in forward arrow movement.  After 90 degrees, the percentage of downward motion is greater than the backward motion and stack begins to limit how much further the bow can be drawn.  Since our draw is only backward, you reach a point when it is no longer possible to to draw.  on an infinitely bendable limb, that would be when the tips point straight back.  recurved tips delay that point.

Offline George Tsoukalas

  • Member
  • Posts: 9,425
    • Traditional and Primitive Archers
Re: Stacking
« Reply #24 on: July 20, 2015, 06:55:24 pm »
Yup.
Geometry. 90 degrees is the magic number. When the string angle gets there, that's it for drawing the bow.
Jawge
Set Happens!
If you ain't breakin' you ain't makin!