FD Drawings

[DC]

Can you make any solid statements about a bow from the FD? For example if the top end of the curve is concave does that definitely mean the bow is stacking? On Sleeks thread Eric posted an FD that shows the entire curve is slightly concave. What can you deduce from that?

[Del the cat]

You can only make educated guesses and generalisations unless the tiller is obviously off and then you'd need see it unstrung, and even then bows can be deceptive. The prettiest bow can be sluggish and a scruffy stick bow can sometimes be surprisingly quick.
You'd need to know what wood too.
I s'pose I'm really saying "no"! (in my opinion of course...)
Del

[SLIMBOB]

You can say that the climb is steeper near the end as opposed to one that might be near level or even one that moves in the opposite direction as you might get with a contact recurve. So yes it does tell a story. Early draw weight is lower and increases toward the end of the draw. Whether or not it functions well is a open for interpretation.

[BowEd]

Anything making the string angle steeper comes closer to stacking.

[Eric Garza]

Just to be clear, DC, are you asking about Full Draw pics or Force-Draw curves? It seems like some people are talking about full draw photos, while others are talking about force-draw curves.

[DC]

Force draw, sorry, full draw never crossed my mind.

[Del the cat]

Oh, maybe I missunderstood.
If you mean the Force Draw curve you should say at trick one!
I thought you meant Full Draw shape...
Anyhow answer is the same .. you could make a bow out of lead and copper, the FD curve would bear no resemblance to the performance!
Del 

[bradsmith2010]

well if the bow is stacking on the full draw curve,, you could say it might not be a good design to draw that far,,

[DC]

You say "if the bow is stacking". Does that mean that a concave curve at the top doesn't mean it "is" stacking? If not, what could account for that curve?

[bradsmith2010]

i am don't quite understand the question, but if the curve is showing that the bow is pulling more weight per inch at the full draw,, it is stacking,,
for example if the bows was pulling smoothly 3lb per inch at 25,,26 27,, but at 28 it increases  5#s and 29 increases  7 #'s,, the curve would show that,,
I am sure someone will chime in and explain it more clearly,, but thats my try at it,,

[SLIMBOB]

That would fit my definition of stacking.  The force draw curve tells us how a bow gets from brace to full draw.  There are different paths bows can take to reach the same weight at a given draw length.  Flat, low early with a sharp increase near the end, or something that might resemble the very reverse of that, early draw weight with a leveling off at near full draw.  If it is taking the first route, it is stacking to some degree to get there in my opinion.

[DC]

Yup, that's what I was asking.