Please define smooth draw force curve

[snowplow]

From what I am reading, I am under the impression that a smooth draw force curve or feeling of a 'smooth draw' is attributed to low draw weight gain per inch of draw pull.

So 'smooth' is a relative term, however, a bow that is 10# at brace and 50# @ 28 is not as 'smooth' as one that is 50# at brace and 50# @ 28?

So in a draw force curve the flatter the ramp the smoother it is right?

One more example; the Toelke Chinook feels as if your close to the full draw weight from brace, so even though it is harder to draw in that sense (pulling more weight longer), it could be called extremely smooth?

[Orion]

Though smoothness is a personal thing, most would agree with the observation in the first sentence.

Of course, your second example in the second sentence is an impossibility with a stick bow.  All stick bows increase weight as they're drawn.

To answer your question in the last sentence, yes, because it has a lot of initial load, its pounds per inch as you draw it should remain relatively low so most would consider it smooth drawing.  

Looking at your earlier post and this one, it seems you're used to shooting a very light bow and find a heavier bow on the stiff side.   Seems you're looking for a bow that draws 50# to feel like it draws 25#.  Unlikely to find it.  Weight is weight.  Whether most of it is on the front end of the draw or the back end, 50#@28 is still 50#@28. Good luck in your quest.

[snowplow]

Thanks for the clarification.

I wasn't very clear on my example. When I said 50# @ brace and @ 28" I meant it as the greatest exaggeration of the principle by way of comparison.

[wingnut]

There are two schools of thought on smooth draw.  One for longbows and one for recurves.  The longbow is as you said;  it gains 3 pounds for every inch drawn from brace to anchor (or there abouts).  The recurve and especially the static recurve is different. It loads heavy in the first 2/3 of the draw say 4.5 pounds per inch and for the last 4 inches drops to 2 pounds per inch.

Both are considered smooth as long as they don't stack at the end of the draw cycle.

Mike

[damascusdave]

Take a look at the chart for the Border Covert Hunter at peteward.com...it is an extreme example of how a recurve force draw curve can vary from the conventional as Mike just alluded to...I think you will find something similar with his Dryad ACS recurve limbs

DDave

[snowplow]

Wingnut, you hit on where my mind was headed. Because if a recurve (heavy at first then slower to gain) is smooth, then a longbow would be the opposite. So what do people call the opposite of smooth? Kind of sounds like longbow shooters dont like 'smooth' bows. Ya know what I mean?

One more question- is it just a feel thing, or does it apply more energy to the arrow (speed)?

For example (exaggerated for effect) the same examples as above.

A bow that is 10# at brace and 50# @ 28 vs. one that is 50# at brace and 50# @ 28?

Will the one with more early poundage transfer more speed/energy to the arrow? Is that the reason why recurves are generally faster?

[McDave]

As Orion mentioned, smoothness of draw is somewhat subjective.  However, I wouldn't say that a longbow is the opposite of smooth.  I have a 66" Toelke Lynx longbow, and everybody who has drawn it has said that it is one of the smoothest drawing bows they have ever drawn.  I think part of the reason for that is that the force/draw curve is probably close to a straight line; in other words, there isn't much of a change in lbs gained/inch of draw from start to finish of the draw.  Probably another reason is that with a 66" length, the string angle at your fingers doesn't change much throughout a 28" draw.  Probably another reason is that the grip feels comfortable.

For me, a rough drawing longbow would be one where the lbs gained/inch of draw changes during the draw, I'm aware of finger pinch, and the grip doesn't fit my hand very well.

I'm sure that the feeling of the shot also influences a person's opinion about the smoothness of the bow, although theoretically it shouldn't, because it happens after the draw is complete.  However, I'm sure most people wouldn't rate a bow with a harsh release and hand shock as being very smooth.

The energy applied to the arrow is equal to the area under the force/draw curve, so a bow that had very little draw weight through the draw, with a dramatic increase in draw weight at the end of the draw, would impart very little energy to the arrow.  A bow that increases very rapidly in draw weight at first, and then either maintains that weight or drops off toward the end of the draw would impart more energy to the arrow.  I think they call that a compound bow, btw!  That said, I don't think most traditional archers would say that a compound bow was particularly smooth drawing, but who cares if you're only holding 20# at full draw?

[katman]

Smooth to me means no large jumps pounds per inch of draw, say 3# per inch for a longbow, although certain aggressive recurves can have a steady decrease in pounds per inch of draw, say 1.9# per inch, at the end of there draw.

It can be more than feel, an aggressive recurve is heavier in pounds per inch at first, storing more energy, and if it is efficient can put that into the arrow yielding more speed.

Here is a link to graphs of draw force curve, dfc, and the first derivative of that curve, the so called smoothness curve. Read the op description.

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=1;t=128522

On the smoothness curve epic(red) starts at 2.8#/inch per inch and then drops slowly to 2.2 at about 18" holds relatively steady until around 29" the rises. Now the poundage pulled is going up the rate of increase per inch is changing.

[nineworlds9]

Snow, these guys basically headed where I was headed in my last email, I was going to write again but they answered first.  Wingnut especially hit the nail on the head about longbows vs recurves.  He should know a thing or two  

[snowplow]

Makes sense guys. Awesome explanations!

[Mike Mecredy]

What I try to achieve, especially with longbows, is the smallest gap in draw weight, as possible, between the starting the draw and reaching max draw. For an example; if I start weighing my bow at 20" and the max draw is 28", and the draw weight is 50# @ 28", the Closer to 50# I can get at 20" the better.  That means the gain per inch is as minimal as I can get.  I like 2# or less per inch. So I'm happy if my longbow draws 34# @ 20", and goes up around 2# per inch until I reach 28".  On one bow I make the gain between 25" and 26" is only about 1.25#, and at that point in the draw cycle it's a good place to "have a break" from stacking. (I get the results I want by making a limb narrow and thick as opposed to wide and thin.) That's the only way I can explain a smooth draw force curve.  I hope that helps

[snowplow]

Yep that helps a lot. Thanks for taking the time!

[Stumpkiller]

Originally posted by snowplow:

So 'smooth' is a relative term, however, a bow that is 10# at brace and 50# @ 28 is not as 'smooth' as one that is 50# at brace and 50# @ 28?
 

In #2 above - if it is 50# at brace and 50# at 28" why bother drawing it?  

I find a bow that loads proportionally to draw feels smoother.  The best for me is one that just starts to stack-up at my anchor.

[ChuckC]

well, da way I see it, if der are no bumps, its pretty smooth !

CHuckC