?Best stat to compare bows PERFormance?

[Matt Green]

Recent article compared a dozen recurve bows by calculating a stat the authors called "comparative efficiency" (velocity/draw wt).
Just wondering what calculation YOU think is the best for head to head comparison. PLEASE, PLEASE focus on performance and NOT that the "grip has to fit, individual preference, etc".

Please state the rationale for your response as well. Not trying to start an argumet, just a healthy discussion.
look fwd to responses.
mg

[Sixby]

I believe every aspect of bow performance including fit and finish should be looked at closely. I personally believe in the complete package. for instance I do not want a fast bow that has bad handshock. I conversely do not want a slow bow the is quiet and smooth with little speed.
Bow performance according to Steve is a fast, quiet, smooth bow , completely sealed against the elements, Well formed and finished in a professional manner. I see absolutely no reason that we should have to settle for less than great in all aspects.  In other words Matt IMHO there is no single best stat if it sacrifices or does not address all other factors which constitute performance./ Including fit and shootability.

God bless you all, Steve

[Stone Knife]

Game taken  

[ishoot4thrills]

If you're talking performance ONLY, then the only way to measure THAT in a bow is with a chronograph. When comparing a bow's performance with another, everything must be the same: arrow weight in grains per pound of draw weight, draw length, type of string, etc.

[Matt Green]

Thank for hte post. AM talking performance ONLY. I don't disagree with the total package theory. I'm wondering if we shouldn't 1. tune for perfection in case tuning alters chrono speed observed and then 2. calculate an efficiency rating using velocity and grains per lb of arrow weight.
Something has to be standardized - a 60lb bow with 180f/s and a 50lb bow with 170f/s are not fairly compared if the arrow weighs the same.
any body else?
mg

[John Havard]

http://www.dryadbows.com/Defining%20Bow%20Performance%20Dryad.pdf

[BobCo 1965]

Personally, I think efficiency or how much of the bows energy goes to the arrow is the best stat to compare.

[joe skipp]

I believe Norb Mullaney used the AMO Standard when testing out Recurves and Longbows. I think it was 60# bow at 30" with a 540 gr arrow. Now I just woke up after working a 12 hr night shift so I could be fuzzy on the specs....    

[Sixby]

Speed means nothing unless it is compared against something. I would suggest that if all bows were compared on an equal basis as suggested say 28 in machine draw and release with same chronograph . same weight of draw , same string type and strand, same weight of arrow. that a lot of manufacturers claims would be going out the window. It is a very fast bow that will put a 10 gpp arrow drawn 28 inches over 190. There are a couple that will do that. Not many.
God bless, Steve

[wingnut]

Now Steve your not saying that some bowyers would fabricate the speed numbers are you?  LOL

That's why we send ours to Blacky for testing.  Total standard criteria on every test every bow.

Then live with the results.  Heck sure I wish ours was a few feet faster but it is what it is when Blacky runs the tests.


Mike

[Jeff Strubberg]

As long as controls like Mike talks about are used, FPS is a reliable way to compare bows to one another.

It's not the best predictor of penetration performance, but that's a measure of bow and arrow as a unit, not just the bow itself.

[hybridbow hunter]

The best way we found is to see on the same curve: speed according to GPP of bow, Dynamic efficiency and KE. This way gives a really good info and it is easy to compare different bows

 

[zze86]

From a pure energy standpoint, you want to compare how efficient the bow is in transferring energy to the arrow. That means you have to look at the force draw curve and consider the bow's total potential energy, then shoot an arrow to get the velocity of the arrow to calculate the kinetic energy in the arrow.

The parameters that the article uses, velocity/peak draw weight, will give very rough estimates of the bow's energy efficiency for they are nested in the potential energy/kinetic energy scenario I presented above. Those #'s will only give a rough estimate because the peak draw weight does not consider the shape of the force-draw curve. For example, a compound bow will have much higher potential energy then a recurve at the same peak draw weight and it is evident as to why when looking at the force-draw curves. I suspect the author chose to do it like that because that information is readily available whereas a force-draw curve is not.

Looking at velocity or FPS alone is, IMO, a selling tool and not a good comparative tool.


Hybrid Hunter - can you elaborate on the dynamic efficiency curve on your graph? I have not seen that before, what does it mean?

[hybridbow hunter]

ZZE86,

Dynamic efficiency change with arrow weight and as we know with the draw force curve the store energy of the bow@ drawlength, it is easy to calculate DE according to arrow mass:
Store Energy X DE= KE= 1/2 X m X V2
As we measure Store energy on our draw force curve and can  get arrow speed (with chronograph) with several arrows we accurately weighted, determining DE for each arrow mass is easy (and we use Excel software to make the curves)

[ron w]

If you can hit what your shooting at with a given bow, then the performance is spot on...at least for you!!  

[Sixby]

Originally posted by wingnut:
Now Steve your not saying that some bowyers would fabricate the speed numbers are you?  LOL

That's why we send ours to Blacky for testing.  Total standard criteria on every test every bow.

Then live with the results.  Heck sure I wish ours was a few feet faster but it is what it is when Blacky runs the tests.


Mike

Mike, Absolutely not on purpose but many do not run tests that are truly comparative. some use IBO ect and they do not compare to trad values like 10 gpp at 28 or even 29 inches would .
As for me I will have Kirk do all my testing when his program is all computerized. He is going way past what anyone is doing at the present time and I am going to be utilizing his expertise and his testing facility. Which by the way is right here in the USA. (Grin)
As to your bows, I can look at the new one and know it is pleanty fast. No flys on that baby at all. I don't have to have Blackies report to know that.

God bless you all, Steve

[LostNation_Larry]

I want a decibel reading in there somehow.  I hate to take a fast bow that is easy for me to shoot but noisy.  Nothing more embarassing than a compound shooter coming into my shop and shooting recurve only to comment on how it is louder than his compound.

[Gen273]

This is a neat thread with a lot of good info!

However for me, it is hitting where I look.

[Bjorn]

I don't base my bow decisions on calculations, oh sometimes I go to Blackie's site, can't think of anything I buy that would be based on formulae. Not saying it is bad mind you just can't see the use. With bows you gotta' shoot them in your own hands-it is personal.

[zze86]

Originally posted by hybridbow hunter:
ZZE86,

Dynamic efficiency change with arrow weight and as we know with the draw force curve the store energy of the bow@ drawlength, it is easy to calculate DE according to arrow mass:
Store Energy X DE= KE= 1/2 X m X V2
As we measure Store energy on our draw force curve and can  get arrow speed (with chronograph) with several arrows we accurately weighted, determining DE for each arrow mass is easy (and we use Excel software to make the curves)

ahhh...I see now. I like it and you're right it does present a lot of good info all at once.