stack?

[knap_123]

what is stack and what causes it?

[Dano]

The way I understand it the closer the string angle gets to 90 degs. the more the bow stacks or the draw curves increases.

[Jesse Peltan]

Stack is a rapid acceleration in the increase in poundage. For example if a bow pulls 2-3# and then suddenly 5-6 it's stacking. Its caused by bow design and materials.

[ProArcher]

Archery Terms

Stacking
A characteristic of bow performance where the force/draw curve rises more rapidly over the final part of the draw.

 http://www.centenaryarchers.gil.com.au/archery_terms.htm#S


Stacking: Disproportionate increase in bow weight during the last few inches of the draw.

 http://fog.ccsf.cc.ca.us/~tkobayas/archery/ArchTerms.shtml

[Pat B]

Like Dano said, stacking happend when and after the string angle at the tip is greater than 90deg. At that point the string is pulling more at the length of the limb and not as much at the flexing limb.
  For example...pull the limb tip back towards you with your hand and the limb will flex. Pulling straight out from the end of the limb and there is no flex or give. At 90deg of string angle the limb flexes less and most of the force is being pulled along the limbs length increasing the draw weight. By adding a slight recurve to the tips, you decrease the string angle allowing the limb to flex more.