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Hello! My son has convinced me to take up archery with him. After building a little range on our land and going through a different bow types I've settled on a Samick Sage for now. I seemed to cooperate better with the Recurve style versus Compound.

My recurve is 62" @ 35#

It's my understanding that the 'sweet spot' draw length is 22-24"

I have a draw length of 30". I have also been drawing it to this length. I'm assuming it's a higher draw weight the more you draw over it's 'sweet spot'? Any idea how to estimate or measure the exact draw weight at 30"?
 

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Most limbs are weighted at a 28" draw. I don't know the exact details of a Samick Sage's draw curve, but I would guess you are pulling close to 41# at a 30" draw.
 

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Never heard of this "sweet spot".. are you referring to one being a characteristic of the Sage itself, or with any recurve in general? As Hartkopf said, draw weights are measured at 28". Draw less than that, weight on the fingers will be less, draw more, more weight. About 2-3lbs per inch over 28" I've been told, which would put your 35# limbs at about a 39-41lb draw.

That's actually really pushing the Sage to the limit in terms of draw weight. You'd really do better with a 64" or longer bow. Otherwise you end up with "stacking", where really you're pulling beyond the design limits of the bow. I believe the Samick Journey is a couple inches longer- you should be able to simply swap the limbs.
 

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It depends on what you call the sweet spot. I have tested bows from 20 to 32 inches of draw on a shooting machine and efficiency is fairly constant. In fact, it actually goes down slightly as draw length increases.

Another measure is pounds/inch at each point in the draw cycle. I measure this as well. Stacking occurs when this numbers starts to rapidly increase. It can feel like you are hitting a wall. A Samick Sage is not the best choice for a person with a 30 inch draw.

It is too short unless you are planning on hunting with it. Target and recreational shooting is best with longer bows, especially with a long draw like you have (How did you determine your draw length? Where do you anchor?). I have not yet had a chance to test a Sage so I cannot offer specifics. I am hoping to do so since it is such a popular bow.

Anyway, I have not been able to quantify a sweet spot with the exception of super recurves which are designed to have the low point of the pounds/inch curve where you release. A conventional recurve has more of a sweet region as far as I can tell, and that is the area prior to stacking.

As far as differences in weight for bows that are drawn a lengths different than 28 inches, 2 pounds/inch is accurate enough for a bow between 35 and 45 pounds. It is just an estimate. I called it an estimate of an estimate of an estimate in the post I am linking to. (See this post http://www.archerytalk.com/vb/showthread.php?t=5359071) . Even the marked weight can deviate. Sages are marked in 5 pound increment. They do not necessarily weigh what they are marked. The weights are rounded.
 

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tkro0 -

The "sweet spot" (maximum efficiency) of any bow is typically, just before the limbs reach their stack or stress point.

The theory:
The stack point is when then increase of draw weight per inch begins increasing at an accelerated rate. (You, as the shooter don't want that.)
The stress point is when the limbs cease to tune as expected. (You, as the technician don't want that.)
Neither condition should harm the bow, but may hinder your development.

The practice:
It's almost irrelevant as far as performance is concerned (in any way you want to define performance) with any modern bow, unless you've passed either of those points. It might show up in a laboratory setting, but not at a range in human hands ...and...
It's also irrelevant because, if you actually have a 30" draw, you've already passed both points with the Sage.

Viper1 out.
 

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The "sweet spot" (maximum efficiency) of any bow is typically, just before the limbs reach their stack or stress point.
That is exactly what I thought until I actually tested it. I ran a series of tests on a shooting machine varying draw length with the same arrow, at constant GPP, and at constant stored energy, and found that efficiency is almost constant over a very wide range of draw lengths. I tested from 20 to 32 inches (I actually think I went to 33 but I have to check my data). I am defining efficiency as the ratio of kinetic energy to potential energy. This is why it is important to define what we mean by efficiency. We need to look at efficiency as one contributing factor of performance. I think many folks use the term efficiency when they are really talking about performance. Of course, this means we have to define performance, which is more complicated.

This has little impact on us as archers. We need a bow that performs will when we shoot it. There may be some value if we could figure out how to quantify performance and plot it by draw length for a bow.

I am not sure what it is that you have defined as the stress point or how you would measure it. I will take a look in your book to see if you have defined it there. I am always open to adding key measures to my test data set.
 

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Steve -

I think it just defined it (and yes, it's in the book). Most bows will reach a point where they will not tune as expected or in fact change tuning results, regardless of how the parameters are tweaked. In my experienced the arrows will usually act weak. I've seen it with a number of long draw shooters (32"+) and usually with bows that are too short. I might be able to speculate on why it happens, but have no way of knowing the exact reason. For most people, not reaching the stack point is enough.

I have yet to see a bow loose performance (Vo) as draw length is increased, as long as the draw length remained in the acceptable limits for the given rig. Yes, there will be a point of diminishing returns.

To be honest with you, I think quantifying "performance" by plotting some data on a curve would end up being more of a marketing ploy that some companies would be more than happy to take advantage of, than any benefit for us. The difference between "peak efficiency" and acceptable efficiency just isn't that great.

Viper1 out.
 

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I think it is more of a measure to be used in the design process. If I want to increase bow performance then I have to have a way of measuring the outcome of my design changes.

As far as choosing a bow for myself, I want something that I can execute well with, and that gives me good sight points for the distances I need to shoot. That means finding the "right" speed, weight and feel, rather than the highest performing, let's say, from a speed standpoint.

As such, I am currently using a 74 inch bow that pulls 32.5 at 32 inches. I hit all FITA field distances easily. My point on is around 35 meters meaning that I limit the number of shots that I have to stringwalk since I can shoot pick-a-point from 30 to 50 meters aiming off the target. I use super recurves to give me the longest string possible so that I limit how much I pull the bow out of balance. The low weight makes execution easier. I have not measured this particular bow yet but I am sure that it is below 180 fps, possibly even high 160's. Definitely not the highest performer from a speed perspective, but higher when you consider points on the scoreboard. At least I hope that will be the case. I have to see how this season goes.

Bottom line, I know how I measure performance for me and it is not the fastest or most efficient bow. I chased speed when I was shooting FITA target and needed to hit 90 meters with the lightest bow possible. I don't have to hit 90 meters any longer.
 

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Not with this bow. I have a bow that does very well at 70 meters that I use for FITA barebow target. It uses 35 pound Border HEX6 limbs and fairly heavy 434 gr Easton ACG arrows. It is 40.5 pounds at my draw. I can shoot 70 meters either with the arrow tip split finger, or aiming with the shelf three under.

I think that 70 might be out of range of my current bow. I hit 50 meters with my high anchor. I get about 10 more by going to my lower anchor. I might be able to get 70 if I go split. I certainly cannot get 90.
 
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