Difference in bows stacking at full draw

[Mark-R]

I suppose you'd have to put this on a drawing board and measure inch by inch, but for those of you with more pracatical hands on experience - is there a big difference (in terms of stacking) between a 50# @ 28" bow and a 54-56# @ 30" bow?

I know every bow is different, I'm just considering "all things being equal" (two identical bows just tillered different).

More to the point - I like shooting 50# give or take.  Am I fine with a 45# bow @ 28", or better off with a 50# bow tillered to my 30" draw?

Thanks,
Mark

[Orion]

Most often, it's the same bow.  I've said this before, but most bowyers don't change the bow lamination taper or thickness for a longer draw, they just build their normal bow (i.e., x pounds @28 inches) and mark its poundage at 30 inches, if that's what the customer wants. Now some bowyers do change the lamination composition to get more performance at the longer (or shorter) draw length.

Generally, mid-weight bows (about 50#@28) will stack about 2 1/2# per inch beyond 28 inches.  However, the amount of stack increases the further one draws the bow so usually a bow gains more weight from 29 inches to 30 inches than it does from 28 inches to 29 inches.

Bow length and design have the greatest infuence on stacking.  Generally a shorter bow stacks faster than a longer bow, and a straight bow stacks faster than a hybrid or recurve.

To repeat.  Your 45# bow at 28 inches is more than likely the same bow as your 50# bow at 30 inches.  They are neither layed up nor tillered differently.  They're just marked differently.

[jhg]

Originally posted by Orion:
...

Generally, mid-weight bows (about 50#@28) will stack about 2 1/2# per inch beyond 28 inches.  However, the amount of stack increases the further one draws the bow so usually a bow gains more weight from 29 inches to 30 inches than it does from 28 inches to 29 inches....

I have to disagree with that statement. Stacking is not a bow adding 2-1/2 lbs an inch. That is adding normal, smooth weight. Stacking is adding over 3 lbs per inch and often more.
Any bow that adds 2-1/2 lbs an inch over 28 is a VERY nice bow. The nicer ones I shot add 2-1/2 through 30" measured at both 29 and 30.

Near my poundage limit I am very senstive to extra weight per inch over 2-1/2 lbs. I can tell the diff between that and 3 lbs an inch. Over that per inch/lbs the bow ceases to draw smoothly. It draws like it has a stumble toward the end of drawing it.

[Night Wing]

Originally posted by Orion:
Now some bowyers do change the lamination composition to get more performance at the longer (or shorter) draw length.

When I buy a custom made bow and with my 30" draw length, I always ask if the bowyer changes the lamination composition to get more performance with my 30" draw.

[Orion]

jhg.  We seem to have a semantics problem.  A lot of folks call the rate at which a bow's draw weight increases stack, as I do. I think that's the way Mark was using the term as well.  Every inch it is drawn, it stacks an additional amount of weight on top of what was drawn before. Now, when the stack increases sharply, usually somewhere beyond 28 inches, it can become uncomfortable, like hitting a wall.  That's called severe, excessive, insert whatever word you like, stack.

Night Wing, What is their answer?  Not trying to be a smart behind.  I just know that a lot of custom builders do not change their lamination and/or taper composition.  In fact, there's usually no need to. Drawing a bow further than 28 inches will increase the speed, performance commensurately.  The challenge comes with building a bow for a shorter draw length.  Bowyers can build a bow to yield peak performance at 26 inches, but then what happens when the person who ordered that bow sells it to someone with a 28 or longer draw.  Extreme stack. Then, the second owner often bad mouths the builder for building bows that stack.  That's another reason a lot of builders take the middle of the road course.  As I suggested before, bow design and length will do a lot more to ensure a proper "fit" to one's draw length than lamination composition.

[jhg]

Ok. Like calling snap shooting target panic or vs versa.

So tell me, if a smoothly progressing draw force is called stack, what do we call it when that draw force suddenly spikes in weight and becomes a wall?    

 Just playing devils advocate... ;0)


Joshua

[Mark-R]

Thanks for all the input.  You guys gave me things to think about thatnever really occured to me.  All good info.  Thanks again.

Mark

[Orion]

Joshua:  I think we're saying the same thing.  And I agree that any bow that "stacks" 2 1/2# per inch beyond 28 inches is a very smooth bow.  However, I tried to convey the fact that most bows don't stack at that rate very long beyond 28 inches.  I think stack is typically viewed as what happens beyond the normal 28 inches of draw. A bow that maintains a constant poundage increase per inch of draw length beyond 28 inches would be described as one that doesn't stack.  Those are  rare, however.  More common are those that tend to increase in poundage per inch beyond 28 inches. (For example ,almost any draw force curve presented in Blacky Schwartz' bow reviews.) These bows are stacking, but not as much as those that really spike/hit the wall, i.e., jump as much as 5# or more per inch.  Guess I've always viewed stack as a relative term.  I.e., This bow's pretty smooth.  This bow stacks a little.  This bow really stacks. This bow hits the wall at 29 inches, etc.

Sorry for getting this track a little off -center Mark.  Hope some of this was helpful to you.

[7 Lakes]

"Hitting the wall" is when your string to limb angle reaches 90 degrees.  There are several ways to avoid this & it becomes an issue mostly in shorter, straight limbed longbows with lots of taper in the limbs.

[Earl E. Nov...mber]

Stack to me is when the weight per inch of draws starts to rise above the normal(Typically 2.5-3# per in) for the bow..  That could be at 25" or it could be at 32"

It is all about the design of the bow, length of riser vs limbs and laminations are just some of the elements

[Javi]

When I draw a bow and it is smooth thru X number of inches and then the weight takes a jump above the normal rate of load per inch of deflection; that is stacking to me.. but what do I know.. I work with spring loads almost on a daily basis.. and what is a bow except a spring..