Request for those who are starting a new bow.

[willie]

  The test was not to level the playing field exactly. More so to demonstrate that in most cases the 24" draw bow would be more efficient if it had never been drawn past 24".

So are you trying to zero in on where to find best efficiency somehow?

[Badger]

No Willie, I am trying to keep the broadhead shoot at 28" and give a reason why I feel that way. I should have said that at the beginning of the thread.

[willie]

Steve,
Ok,
this has been an interesing thread in it's own rights. My question was about bowbuilding and efficiency, not about the broadhead shoot at all.

[avcase]

I see the real goal of Steve’s challenge is showing how we may be losing more performance due to over stressing the Wood than we may realize. I feel it is very insightful!

Regarding test criteria, we can scale the GGP based only by power stroke, but it ignores a few aspects of bow design and the bow-human interface. For example, let’s say we have an “average” archer with a 28” draw (comfortably draws 26-1/4” from deepest part of the grip). Bow #1 works best with a 5” brace height, bow design #2 works best with brace height set at 7”. Both bows are designed to perform best at 28” draw but they have different draw stroke lengths. Does it make sense to modify GGP of the bow with a longer draw stroke so it shoots a heavier arrow?  Or does it make sense to set both bows at an equal but sub-optimal brace height just to keep the power stroke consistently? 

Alan

[DC]

No Willie, I am trying to keep the broadhead shoot at 28" and give a reason why I feel that way. I should have said that at the beginning of the thread.

How is this going to help that? Sorry if I'm a bit slow.

[DC]

I see the real goal of Steve’s challenge is showing how we may be losing more performance due to over stressing the Wood than we may realize. I feel it is very insightful!

Regarding test criteria, we can scale the GGP based only by power stroke, but it ignores a few aspects of bow design and the bow-human interface. For example, let’s say we have an “average” archer with a 28” draw (comfortably draws 26-1/4” from deepest part of the grip). Bow #1 works best with a 5” brace height, bow design #2 works best with brace height set at 7”. Both bows are designed to perform best at 28” draw but they have different draw stroke lengths. Does it make sense to modify GGP of the bow with a longer draw stroke so it shoots a heavier arrow?  Or does it make sense to set both bows at an equal but sub-optimal brace height just to keep the power stroke consistently? 

Alan

Gotcha Maybe people are just going to accept that different design bows do things differently. If you design a bow to shoot a 150 grain arrow across the Salt Flats don't take it hunting elk and vice versa. And if you enter a bow in a competition be aware of it's limitations.That doesn't help short draw people though Sorry Sleek

[Badger]

    I haven't really done much testing in this area since about 2010. The way I used to test was to chart the FDC establish how much stored energy I had and shoot an arrow weight that corresponded to stored energy. By all rights if the bowyer does his part the bow shouldn't loose all that much drawing it further. But I can tell you from experience that I was shocked when I found out how much I was actually loosing in a lot of cases.

[willie]

shoot an arrow weight that corresponded to stored energy.

So if I understand you correctly, if you had 60 ft lbs stored energy, you might move the decimal point and shoot an arrow of 600 grains?
rather than do a 10gpp based on the max pounds draw force?

[Badger]

shoot an arrow weight that corresponded to stored energy.

So if I understand you correctly, if you had 60 ft lbs stored energy, you might move the decimal point and shoot an arrow of 600 grains?
rather than do a 10gpp based on the max pounds draw force?

  That is pretty much what I considered my favorite method but too much trouble.

[Selfbowman]

Ok if I did it right here is some for a overbuilt bow. I guess.
70 inch Osage pyramid bow . 10" handle. 2-1/8 at fades , 1-3/8 at mid limb, 5/16 tips.
40x24=9360 devided by 28 =34x10 = 340gr.
I had a 360 grain arrow was as close as I could get. At 24" draw 148 fps
480 gr at 28 156fps
360 gr. At 24  146
About fifteen minutes latter restrung bow and pulled to 24 then 28then 24
At 24. 36.20
At 28 47.32
At 24 37.84
2" set straight away oh weight of bow   31oz.
This bow is for 50 # at 29-1/2 in. draw person.
Ok what's my score? :-)
Arvin

[Badger]

Ok if I did it right here is some for a overbuilt bow. I guess.
70 inch Osage pyramid bow . 10" handle. 2-1/8 at fades , 1-3/8 at mid limb, 5/16 tips.
40x24=9360 devided by 28 =34x10 = 340gr.
I had a 360 grain arrow was as close as I could get. At 24" draw 148 fps
480 gr at 28 156fps
360 gr. At 24  146
About fifteen minutes latter restrung bow and pulled to 24 then 28then 24
At 24. 36.20
At 28 47.32
At 24 37.84

  Arvin, the test has to be taken before the bow has ever been past a 24" draw? Was this a brandnew bow you just finished today?
2" set straight away oh weight of bow   31oz.
This bow is for 50 # at 29-1/2 in. draw person.
Ok what's my score? :-)
Arvin

[Selfbowman]

Yes this was done today. I did start at 24 then went from there. I did not pull to 29.5 until after the test. This bow has 6 arrows thru it. Yes it was a bow that was floor tillered this morning when I got up. I am a bit disappointed in the speed and the set. Cant explain it. I figured this bow would be in the 170s . Moisture reader said like 7%. Extremely straight grained Osage stave. Very flat back.i don't get it. Never went passed draw weight. Oh I shot a 500 gr arrow into 5-7 mile an hour wind for about 165 yds. May have got another 10-15 if the wind would have been reversed . Oh well did what I know to do. Arvin

[Selfbowman]

Bow two . Osage , 70-1/2ntn,10 inch handle, 1-7/8 at fades, 1-3/8 at mid limb, 5/16 tips, weight of bow 28oz.
At 24-43.88. 376 gr. Shot same 340grain arrow 157 fps
At 28-53.06.   530 grain arrow 165 fps
At 24. 340 gr arrow    158
 One inch set after 10 arrows
Will shoot for cast later today.

[Selfbowman]

You want force draw on these too?  Arvin

[Badger]

   Not sure how to comment on this. In both your tests the second 24" shot was faster than the first. At the same draw weight it would make sense that they stayed the same if the bow had taken no additional set. So as far as this test goes i would say inconclusive. As far as the bows go I think I would cut that one down a bit and narrow it up some.
maybe cut it down to 67" and narrow it down until you had about 50# or 21 oz. A lot of mass on that bow.