Primitive Archer

Main Discussion Area => Bows => Topic started by: Badger on April 24, 2018, 03:59:56 pm

Title: Request for those who are starting a new bow.
Post by: Badger on April 24, 2018, 03:59:56 pm
    Would like to get some feed back on this from those here with a chrono who are currently building a bow but have not yet drawn it past 24".

  Here is the experiment.  When you get to 24" draw but have never passed it  please take your current draw weight multiply by 10  say 44X10=440  then multiply that by 24 and then divide by 28.  In this case it would be 377 grains. So please shoot an arrow of the right weight through the chrono at 24" and then when you finally get to 28" shoot another arrow through the chrono at 10 grains per pound. Last request, go back to 24" recheck your weight and recalibrate your arrow weight accordingly and shoot through the chrono again and please report to us all 3 speeds. I already know how it works out for me but I would like for a few others to report on how it works out for them.

  Theoretically if the bow takes no set all 3 shots should be about the same.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on April 24, 2018, 04:53:34 pm
This should be fun, and I agree with your conclusion.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 24, 2018, 05:01:19 pm
  Here is what is interesting about this test. best case scenario all 3 shots the same. If the 28" draw ever exceeds the 24" draw it would invalidate the test for any number of reasons which could also include invalidating the formula.

  My prediction is this. First 24" shot will be the fastest in all cases. 2nd 24" shot will be the second fastest and 28" shot will always be the slowest. The 28" shot and the second 24" shot should be pretty close, if they are too far apart it would indicate a bad test for any number of reasons. Aside for the point I am trying to make this little test really drives home how important it is to avoid set.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on April 24, 2018, 05:03:12 pm
As an added thought, the difference in energy can be calculated at the 24 inch draw before and after taking it to 28, and energy loss can be actually quantified and seen. Then you can also see the loss in efficiency, I love it.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 24, 2018, 05:23:19 pm
As an added thought, the difference in energy can be calculated at the 24 inch draw before and after taking it to 28, and energy loss can be actually quantified and seen. Then you can also see the loss in efficiency, I love it.

  Sleek I think that is what I defined in the test. If not I may need to rewrite it. I have done this test myself countless times so I am very familiar with how it plays out.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 24, 2018, 07:08:18 pm
Will do. I've got a 68" Saskatoon(Serviceberry) close to that now.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 24, 2018, 07:13:51 pm
Will do. I've got a 68" Saskatoon(Serviceberry) close to that now.

  Appreciate!!
Title: Re: Request for those who are starting a new bow.
Post by: StickMark on April 24, 2018, 10:09:06 pm
I will try to borrow a friend's chrono.  This and the 10gpp rule is fun to think and play with.  In 2012, buying a hickory bard, never thought I would have so much sheer fun doing this passion.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 24, 2018, 10:50:39 pm
  I do my formula just slightly different than Sleeks. I use it as a percentage of the power stroke. So if you test the bow at 24"  you would use 8.2 grains per pound of draw weight.
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on April 25, 2018, 06:18:26 am
My osage is at 50@20 and has not been pulled further than that, will not be able to work on it for the next ten days so if you are not in a hurry I can do it when I continue working it
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 25, 2018, 11:04:12 am
I just realised that I can't draw 28". At least not accurately enough to get chrono results. This is the motivation I need to build a shooting machine but you'll have to wait a bit longer. But with better results. :D
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 12:25:47 pm
My osage is at 50@20 and has not been pulled further than that, will not be able to work on it for the next ten days so if you are not in a hurry I can do it when I continue working it

  Thanks Leon, hopefully it will just filter in.

Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 12:28:43 pm
I just realised that I can't draw 28". At least not accurately enough to get chrono results. This is the motivation I need to build a shooting machine but you'll have to wait a bit longer. But with better results. :D

  DC, take your first reading at 22" or so if you haven't passed that yet. Use an arrow for 22" that is 7.2 grains per pound or sleeks method 7.8 grains per pound. Maybe compromise at 7.5.
Title: Re: Request for those who are starting a new bow.
Post by: avcase on April 25, 2018, 12:33:31 pm
Steve,
I am trying to understand why you state that a bow’s performance would fall off beyond a 24” draw length?  I could understand that this would be true if the bow is designed to the material limits for a 24” draw, but then drawn beyond this. It just means the bow design is not optimal for the longer draw length, correct?

There is something else that could come into play which may reduce efficiency which is not due to overstressing the materials. If the bow draw weight is light and the draw length is long, then this requires more working limb length. This reduces a bow limbs secondary natural frequencies which can rob efficiency.  It is a similar issue low draw weight horn bows have compared to high draw weight horn bows.

Yet another reason this can occur is a shorter draw length has a proportionally better force-draw energy storage since it is less likely to stay out of the stack-zone, and the hump in the beginning of the force-draw curve takes up a bigger proportion of the whole.

The results of this test are also swayed heavily based on how the test arrow mass is adjusted for draw length too.

Alan
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 12:55:02 pm
  Allen, that is exactly right. In all most all cases the bow will show at a very minimum some signs of overstress usually past 26" on a well designed bow. I have yet to see one that showed zero sign of stress. But I haven't tested all of them obviously.

  Allen, how would you adjust for shorter draw. When I firt started doing it I based it on stored energy that I actually measured. Too much trouble so I switched to a method just using an equal percentage of power stroke ratio. I don't think any method is perfect and that is why I am against using it trying to level the playing field. I don't think it can be done with any real accuracy.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on April 25, 2018, 05:17:56 pm
Steve, I'm sure you've come across this article....http://www.primitiveways.com/Bow_and_Arrow_Efficiency.pdf
I recently found it when trying to get more information about bow hysterisis. 
Are the results saying that the more you draw a bow the less efficient it will be?  So related to your experiment, a 24" draw may have 15% loss due to internal friction, where as a 28" draw would have 20% loss due to internal friction, regardless of set.  Or am I reading this wrong?
 
   
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 06:49:15 pm
Steve, I'm sure you've come across this article....http://www.primitiveways.com/Bow_and_Arrow_Efficiency.pdf
I recently found it when trying to get more information about bow hysterisis. 
Are the results saying that the more you draw a bow the less efficient it will be?  So related to your experiment, a 24" draw may have 15% loss due to internal friction, where as a 28" draw would have 20% loss due to internal friction, regardless of set.  Or am I reading this wrong?
 
   

      I don't remember the kinds of percentages that were involved because they were all over the place with different bows. A perfectly designed and tillered bow would have hysteresis more similar to a fiberglass bow. Once a bow has been drawn past a certain point it can never be the same at that point again. The draw length is only pertinent once the set starts taking place. If everything is perfect it will react the same at 28 as it did at 24. The point is that once you have past 24 you can never go back and have the same performance as you did the first time unless everything was perfect. Most all 28" draw bows have at least some signs of set, some of them I see here are surprisingly fresh at 28" but I would still guess they have taken at least some set.  Thats why on my test I suggested we should an arrow at 24" when the bow has still never been drawn past 24" and then we go back after it has been drawn to 28" and shoot another arrow at 24" and compare the difference.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 25, 2018, 07:48:38 pm
So the old "man height" logic may be right after all. A six foot guy probably wants a 72" bow rather than a 66". It's strange that while bowyers were shortening bows they never noticed diminishing performance.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 25, 2018, 08:01:33 pm
This is where a self fulfilling prophecy starts limiting things.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 08:16:09 pm
So the old "man height" logic may be right after all. A six foot guy probably wants a 72" bow rather than a 66". It's strange that while bowyers were shortening bows they never noticed diminishing performance.

   If the bows are wide enough and thin enough to take the bend they will do it. I tested one yesterday 50" long  50#@24"   I lowered it from 60#@24". I used the handicap method of lowering the grains per pound based on the draw length. It was hitting 182. This bow is really designed for very light arrows though in the 200 grain range. I think I was shooting about 410 grains.   As far as shorter bows taking more set and not performing as well. I think a good portion of them do suffer while some guys are able to handle it. Longer bows store more energy anyway.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 25, 2018, 09:34:12 pm
Shooting machine is about done. I've shot one arrow. I followed Del's lead with some of Jan's ideas. Scary rig to use. Should be back to bows tomorrow.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on April 25, 2018, 09:37:33 pm
I have one that I’ll be finishing up in the next couple weeks. It will be a little overbuilt though at 28” as it’s designed for 29.5” draw.  Not sure if that matters.  I know it will take some set at 28” though, and going back to 24” will results in lower speeds.  So will this more or less quantify how much energy was lost to set?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 25, 2018, 10:00:14 pm
I have one that I’ll be finishing up in the next couple weeks. It will be a little overbuilt though at 28” as it’s designed for 29.5” draw.  Not sure if that matters.  I know it will take some set at 28” though, and going back to 24” will results in lower speeds.  So will this more or less quantify how much energy was lost to set?

  That will be interesting. Just make sure your first shot at 24" is before it has ever been drawn past 24". If your second shot at 24 is pretty close to what your first shot is you know you did a good job on the bow. The draw weights will be different but the comparison should be the same because of adjusted arrow weight both times.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on April 25, 2018, 10:16:58 pm
Okay. This sounds fun. Hopefully I will learn a thing or two in the process.  I may have to cut down some arrows.   I don’t think any of them are that light.
Title: Re: Request for those who are starting a new bow.
Post by: Yellowstave on April 25, 2018, 11:00:29 pm
So correct me if im wrong.. if performance drops off after 24", then wouldnt a person with a shorter draw length, lets say 26", have less loss of performance than a guy with 28 inch draw and therefore achieve greater cast??. 
Title: Re: Request for those who are starting a new bow.
Post by: Hawkdancer on April 25, 2018, 11:27:40 pm
I'm sort of in with DC, my draw length is 26".  A 22" arrow at 7.5 is no problem, but what weight at 26"?
Hawkdancer
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 26, 2018, 02:02:22 am
I'm sort of in with DC, my draw length is 26".  A 22" arrow at 7.5 is no problem, but what weight at 26"?
Hawkdancer
   9.2 should work
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on April 26, 2018, 03:30:38 am
I think Alan makes the most since to me with his explanation. So most of our set occurs between 24-28" if we don't go past our intended draw weight in the tiller process? That seems to be where mine happens also just thinking back. So extra mass in width vs. set . Which robs cast the most? That's what I have been trying to figure out also. But I have not built that many yet.  Arvin
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 26, 2018, 08:02:00 am
      Allen, I think you could equalize the test pretty well by ignoring the 28" shot and just comparing the before and after 22 or 24 inch shots made at the same grains per pound regardless of draw weight. I personally don't feel there is a good way to even the playing field by using a set formula to adjust weight. Lots of variables that doesn't allow for.
Title: Re: Request for those who are starting a new bow.
Post by: willie on April 26, 2018, 01:21:46 pm
     . I personally don't feel there is a good way to even the playing field by using a set formula to adjust weight. Lots of variables that doesn't allow for.

There can be a difference between a formula of "what is supposed to be", and a formula derived from actual shooting stats.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 26, 2018, 01:30:18 pm
     . I personally don't feel there is a good way to even the playing field by using a set formula to adjust weight. Lots of variables that doesn't allow for.

There can be a difference between a formula of "what is supposed to be", and a formula derived from actual shooting stats.

  Different styles of bows will have different types of fdc's. I doubt a perfect formula for this really exists.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on April 26, 2018, 02:02:48 pm
     . I personally don't feel there is a good way to even the playing field by using a set formula to adjust weight. Lots of variables that doesn't allow for.

There can be a difference between a formula of "what is supposed to be", and a formula derived from actual shooting stats.

  Different styles of bows will have different types of fdc's. I doubt a perfect formula for this really exists.

Equalizing  all bows to eachother is neither possible nor the intention. The intention is to equalize all archers to eachother regardless of draw length and weight. What this formula actually does is make the differences between bows stand out more clearly.

Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 04:38:11 pm
OK first test, 68" Service Berry 40#@ 24". The bow had a little deflex section. I traced the profile on some paper. The deflex was messing with my head so I did a heat treat to about 2" of relex and tillered out to 24". The bow was now back to it's original profile minus about a 1/4". Call that set or just the heat treat pulling out, I don't know. Anyway I shot it through the DC Bow Machine Mark 1.5 with a 342 grain arrow(I had to modify one so I hope that's the right weight). I got back to back to back 178's, 3 of them. Now I can go for 28". I haven't done that for a while, it's going to be scary. :D :D
Title: Re: Request for those who are starting a new bow.
Post by: sleek on April 29, 2018, 05:01:45 pm
Tjanks for taking the initiative on this Dc. Looking forward to results.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 05:55:32 pm
OK I got to 28" took about another 1/2" set. So 40#@ 28" shot 184fps 3 times. Then if I did it right went back and measured the draw weight at 24", it was 33 ish pounds. Ran that through Steve's formula and got 274 grains. Lightest arrow I have is 294 so I used that and got 162fps twice. I just did two because that arrow don't fly worth soup. So 178,184 and a questionable 162. 20 grains diff, maybe in the 170's
There ya go!

Oh, the 40@ 28 was with a 396 grain arrow, closest i could get to 10gpp.
Title: Re: Request for those who are starting a new bow.
Post by: willie on April 29, 2018, 07:08:34 pm
so 40@24 before and 33@24 after?  I wonder if a guy can use that to see if his tiller goal was too high or too low?(for 28")
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 29, 2018, 07:12:28 pm
   So the formula is off?

 He is  tillering to get to 28",  no?

Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 29, 2018, 07:16:47 pm
OK I got to 28" took about another 1/2" set. So 40#@ 28" shot 184fps 3 times. Then if I did it right went back and measured the draw weight at 24", it was 33 ish pounds. Ran that through Steve's formula and got 274 grains. Lightest arrow I have is 294 so I used that and got 162fps twice. I just did two because that arrow don't fly worth soup. So 178,184 and a questionable 162. 20 grains diff, maybe in the 170's
There ya go!

Oh, the 40@ 28 was with a 396 grain arrow, closest i could get to 10gpp.

  You missed the most important number the 24" shot before it had been drawn past 24". With that speed I doubt you lost much as you progressed.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 07:18:14 pm
I just checked my scale. I have two scales and if I hook them together and pull to 40# the other says 42#. I was using the one that reads high so if anything the weights are about 2# lower.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 07:19:54 pm
OK I got to 28" took about another 1/2" set. So 40#@ 28" shot 184fps 3 times. Then if I did it right went back and measured the draw weight at 24", it was 33 ish pounds. Ran that through Steve's formula and got 274 grains. Lightest arrow I have is 294 so I used that and got 162fps twice. I just did two because that arrow don't fly worth soup. So 178,184 and a questionable 162. 20 grains diff, maybe in the 170's
There ya go!

Oh, the 40@ 28 was with a 396 grain arrow, closest i could get to 10gpp.

  You missed the most important number the 24" shot before it had been drawn past 24". With that speed I doubt you lost much as you progressed.

Go back a couple of posts, it's there. I got 178fps at 40@24
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 07:25:32 pm
   So the formula is off?

 He is  tillering to get to 28",  no?

If I'm following you. I was tillering as if I was going for 40#@ 28". When I got to 40#@24 I stopped and shot the first batch. Then I continued on to 40#@28".
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 29, 2018, 07:33:44 pm
Yes. Just confirming.

 I wasn't sure if willie was thinking the weight drop was just due to the increased draw.

 To me a better test would just be to shoot the bow at 24, draw it to 28 and shoot again and then shoot it at 24 again.

   Adjust arow weight appropriately each time.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on April 29, 2018, 07:39:42 pm
 Ok, I didn't think you had gotten a good shot off the first time around.
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 07:41:52 pm
I was quite surprised at the speed at 24".
Title: Re: Request for those who are starting a new bow.
Post by: willie on April 29, 2018, 07:50:12 pm
Yes. Just confirming.

 I wasn't sure if willie was thinking the weight drop was just due to the increased draw.

 To me a better test would just be to shoot the bow at 24, draw it to 28 and shoot again and then shoot it at 24 again.

   Adjust arow weight appropriately each time.

I was thinking the weight drop is about how well you choose your weight goal. Are you proposing the better test would be to to take the bow, 40@24 and just draw it out to 48 or whatever @28, without tillering to make 40@28?
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 29, 2018, 08:07:45 pm
Yes.  It seems like it would reduce additional factors.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 29, 2018, 08:12:11 pm
  Here is what is interesting about this test. best case scenario all 3 shots the same. If the 28" draw ever exceeds the 24" draw it would invalidate the test for any number of reasons which could also include invalidating the formula.

  My prediction is this. First 24" shot will be the fastest in all cases. 2nd 24" shot will be the second fastest and 28" shot will always be the slowest. The 28" shot and the second 24" shot should be pretty close, if they are too far apart it would indicate a bad test for any number of reasons. Aside for the point I am trying to make this little test really drives home how important it is to avoid set.

Well? 
Title: Re: Request for those who are starting a new bow.
Post by: DC on April 29, 2018, 08:22:28 pm
Is anyone else doing this? I'd hate to base anything on one test, especially mine. ;D ;D
Title: Re: Request for those who are starting a new bow.
Post by: PatM on April 29, 2018, 08:35:31 pm
Steve said he did it.
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 01, 2018, 12:48:24 pm
totday I had some time to do this small test:

Bow: osage rd, 65” ntn (from the narrow stave I posted about earlier)

Shot fresh at 45@24
Arrow weigth: 385 grain
Speed: 180 fps

54@28
Arrow weight: 540 grains
Speed: 177 fps

Bow dropped half a pound in weight
44.5@24
Arrow weight: 382 grains
Speed: 176 fps

All three arrows are 11/32 pine with 5” turkey fletching.
All three arrows where shot ten times, no real big diffences in speed

Below some pics of the bow, arrows, weight and speeds (euro chrony so speeds are meters per second)

45@24
(https://farm1.staticflickr.com/982/41828288201_e2ebaed2d5_z.jpg)

54@28
(https://farm1.staticflickr.com/974/41786426992_58984df7d9_z.jpg)

44.5@24
(https://farm1.staticflickr.com/964/41786427042_7ecb555376_z.jpg)

Osage reflex/deflex
(https://farm1.staticflickr.com/825/40932265045_1aa649526f_z.jpg)
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 01, 2018, 01:06:05 pm
Is it too late to back out?  haha.  I didn't think you all were going to be making bows that fast.  I'm going to get embarrassed.
Sweet bow btw leonwood.
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 01, 2018, 01:26:16 pm
Is it too late to back out?  haha.  I didn't think you all were going to be making bows that fast.  I'm going to get embarrassed.
Sweet bow btw leonwood.

Haha thanks, I was working in this bow already so it was easy to do the experiment. I will finish the bow in the next week or two and post it in a new thread since it is my first osage bow
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 01, 2018, 01:30:34 pm
Leon, you got what Badger predicted( I think). I wonder what I did? Maybe the heat treat messed it up. Did you heat treat at all?
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 01, 2018, 01:35:27 pm
You dropped weight to get 28".  He just drew his farther.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 01, 2018, 01:45:17 pm
Why didn't I see that :-[ :-[
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 01, 2018, 02:14:57 pm
Leon, you got what Badger predicted( I think). I wonder what I did? Maybe the heat treat messed it up. Did you heat treat at all?

Yes I did heat treat, I usually do this when I am at fullbrace and tillered to my final weight but at  about 18” so I can scrape the darkest stuff off the belly and  finetune the tiller a bit
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 01, 2018, 02:17:15 pm
You dropped weight to get 28".  He just drew his farther.

Exactly, just tillered it to 24 and thought it waa good enough to go to fulldraw from there. Will start shooting it in now and finish it at 50@28
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 01, 2018, 06:58:49 pm
You dropped weight to get 28".  He just drew his farther.

Exactly, just tillered it to 24 and thought it waa good enough to go to fulldraw from there. Will start shooting it in now and finish it at 50@28

Only lost half a pound @ 24" in the last four inches? Pretty respectable "no set", and weight goal setting.

cool looking bow, too  :OK
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 02, 2018, 01:28:28 am
You dropped weight to get 28".  He just drew his farther.

Exactly, just tillered it to 24 and thought it waa good enough to go to fulldraw from there. Will start shooting it in now and finish it at 50@28

Only lost half a pound @ 24" in the last four inches? Pretty respectable "no set", and weight goal setting.

cool looking bow, too  :OK

I deflexed the handle and heat treated it so I think that has something to do with the low set. And shot only about 50 arrows throught it by now, still the same at 24 though.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 06:42:24 am
   Leon, that looked like a good test, you did a very good job on that bow! That is only a very small loss. I appreciate you doing this!

 I am hoping to keep this thread going for a while and get more guys to feed in some numbers. Don't be embarrassed if you don''t match Leons numbers. I would be tickled pink to get numbers like that. We need the good bad and the ugly here, it helps all of us.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 06:47:52 am
You dropped weight to get 28".  He just drew his farther.

  The test does work out better if you don't have to drop weight but if the formula is right on it shouldn't matter. I have my doubts about the accuracy of the formula although I do know it is close.
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 07:38:33 am
Good post leonwood.Shows what freshness in a bow is like with the pursuit of good tillering and design in mind.Nice bow and good work on that one.With minimal set like that on self bows I make here they usually will hold that speed @ 28" after being broken in.Not trying to take away your thunder here because that is a very nice bow and would be proud to have made it but occasionally I will have one that shoots into the lower 180's @ 28".Not near all of them but into the mid 170's usually.One or two I know still shoot the lower 180's after a hunting season and a summer of 3D season with well over 2000 arrows through them.One of them did'nt get any heat treatment.No deflex in the handles though.
Would of liked to test those bows fresh @ 24".Made a bow from the other half but with a rounded belly and it shot in the mid to upper 170's.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 07:42:22 am
  Ed, I think any bow hitting up near or at the 180 range is not going to show much difference at the fresh 24" or the finished 28". It is pretty common to see bows fresh at 24" hitting at 180 and then fall back to low 170's after hitting 28".
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 07:47:58 am
Your probably right.I'd have to see it for myself through my own testing though.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 07:52:00 am
  It would be somewhat dependent on the design as well. A very aggressive design might be capable of 190 fps when perfectly executed but because of the high stress nature of the design reaching full draw without set is a lot more challenging. In a case like this you might see a bow hitting close to 190 at 24 then dropping off to 180. But in bows with more basic designs and just a little reflex hitting about 180 is excellent and not much more can be expected.
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 08:02:22 am
I'd have to agree with you about that.The bows I speak of have flipped tips with barely 3" of set back of tips.With not near perfect wood in them.Knots and wiggles very evident.They are eye opening that's for sure especially after going through longer time consuming efforts with other bows only gaining 10 to 15 fps results.
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 02, 2018, 08:03:04 am
   Leon, that looked like a good test, you did a very good job on that bow! That is only a very small loss. I appreciate you doing this!

 I am hoping to keep this thread going for a while and get more guys to feed in some numbers. Don't be embarrassed if you don''t match Leons numbers. I would be tickled pink to get numbers like that. We need the good bad and the ugly here, it helps all of us.

Thanks Steve!, this bow was designed for low stress and not for raw speed. I want to shoot the summer 3d competitions with this one. Just for fun I shot my bl hld static (63@26) with the same 24 inch arrow and got 195 fps, has nothing to do with the test but was just curious ;D
I did make an easy setup for my chrono sowill start using it more often now.

And on my next bows I will repeat this test and post results here
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 08:12:15 am
Bows I'm speaking of are low stress bows.Reason why they stay the way they are.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 08:20:02 am
 I agree Ed, I have had the best luck with conservative designs. I think low set and low stress trumps most everything else.
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 08:26:15 am
Myself with wood bows I'd rather not use any heat at all on these bows.Just a thing I have about heat weakening wood sometimes.Not always of course and type of wood heat treated considered too.Just flipping the tips some and working with naturally slightly reflexed bows.Seems to me most times those hold up the best.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 02, 2018, 09:14:28 am
If I'm getting this right Leon didn't do any tillering between the tests, he just changed arrow sizes. I took a lot of wood off between tests 1 and 2. Surely this would skew the results. Jump on me if I'm wrong. :D
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 02, 2018, 09:49:27 am
Don,

I agree that the way the tests were done (yours and Leons) are not the same, but as badger suggests, perhaps the results are similar.? It would be nice to clarify which way the experiment is to be run if results are to be compared.


a few thoughts.....

1. if the bow is tillered to your weight goal at 24, then just drawn out further without removing more wood, then you are being asked violate the "never pull harder than your weight goal" principle.  Leon just happened to be at 45@24 even though his weight goal for the finished bow was 50@28. Other folks might be 50@24 if tillering a the more usual way, putting the bow closer to 60@28 when "just drawn out". Perhaps not the best pratice for a low set bow intended to finish at 50@28?

2. if wood is removed between the first test @24 and the test @28, then the second test @24 is done with less wood than the first test @24.
would this second test @24 be all that useful? apples oranges etc.

3. Does one have to make three arrows all at 10GPP, or can an arrow that's "close enough"  be used and kinetic energy be calculated from  1/2 MVV to make the comparisions,?

Steve, do you have a quickie way to make test arrows of various weights? aluminum with inserts or something similar?
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 02, 2018, 09:53:50 am
Leonwood, were you using some sort of shooting machine?  I'm trying to figure out what's the best way to shoot right at 24" draw.  It seems it would be hard to get consistent results trying to eye a mark on the arrow. 
I don't want to build a shooting machine.  I would rather spend that time building another bow  ;D
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 10:05:05 am
  Ben, no substitute for a shooting machine but you can get very good and accurate shooting over a chrono by hand if you practice enough.

Don & Willie, not taking wood off does give a superior read out for the test results but most tests will be taken removing wood to avoid going over. This method relies more on a good formula. I believe that Leon used Woodbears formula, my formula based on string travel uses slightly lighter arrows. I think the true formula might be somewhere inbetween the two but closer to Wood bears. Once the bows have been draw all the way out the numbers at 24" and 28" should match if the formula is good. Leons pretty well match within 1 fps. I would rather see the 1 fps on the faster side than the lower side as we know we pick up just a tad more hysteresis drawing it further but over all the formula looks pretty good. Avoiding dramatic differences is what we are mostly looking for using an imperfect formula. 
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 02, 2018, 10:22:41 am
Steve,

woodbears "formula" give a slightly different arrow weight than your "formula" for an arrow weight to conduct the test with.  But isn't kinetic energy what we are after here? Easily calculated from either weight arrow, or even a slightly different weight arrow?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 10:44:28 am
  I don't think so because the heavier arrow and longer draw will always have more KE. maybe ratio of KE to draw weight? The formula we have been using is supposed to equalize stored energy ratios.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 02, 2018, 11:24:59 am
Steve,

"formula" is a confusing choice of words in this discussion. It can refer to an estimate, or to the equation that defines a physical law of motion.

woodbears method is a way to estimate results.  Your method is similar, but it uses powerstroke rather than total draw length, gives a slightly different result, but is still an estimate?

"ke=1/2 mvv"   when written out, is casually called a formula, but the relationship described between energy, mass and velocity is really a physical law.  Only one correct value for any particular weight arrow at a given speed.

Not sure if I should go on, as it may be sidetracking this discussion, but I think it is an important distinction to make if we are to understand the mechanics of the bow.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on May 02, 2018, 11:56:17 am
No formula can be perfect here, cause it represents perfect world scenarios. If every bowyer who uses the formula built perfect bows, id wager the formula is spot on. How ever, there is a variable that the formula can not account for, and thays the human error variable. You cannot accurately predict how well a lerson tillers a bow to get desired results the formula predicts should exist.

But it will tell you how good you did.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 12:10:13 pm
No formula can be perfect here, cause it represents perfect world scenarios. If every bowyer who uses the formula built perfect bows, id wager the formula is spot on. How ever, there is a variable that the formula can not account for, and thays the human error variable. You cannot accurately predict how well a lerson tillers a bow to get desired results the formula predicts should exist.

But it will tell you how good you did.

   I know what you are saying Willie, they are using a formula to arrive at an estimate. That is why I prefer not to use any method other than 10 grains per pound at 28" draw.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 12:12:21 pm
Myself with wood bows I'd rather not use any heat at all on these bows.Just a thing I have about heat weakening wood sometimes.Not always of course and type of wood heat treated considered too.Just flipping the tips some and working with naturally slightly reflexed bows.Seems to me most times those hold up the best.

   I use heat to set up my profile but don't do any actual heat treating. I am not really sure if the amount of heat I apply while straitening out the bow has a heat treat effect or not.
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 12:22:50 pm
No Steve intermittingly like that I don't think so myself.A spot or two 1" one on each limb I would think not.A good heat treatment is a torturous cell changing experience most times depending on how stressful the profile made is.That goes for alterations too I guess if they are extreme.
Some woods like hickory don't seem to be affected by heat as much as others I would say though.Guess what I'm saying is it might be more weakening to some woods more than others.Especially on the working parts of limbs more so than the static of course.
No matter.
Glad your getting results in from your proposed test especially from other talented bow makers on here.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 02, 2018, 12:32:40 pm
Here's an interesting quote from Mason's book.

" Lieut. Allen, U. S. Army, has described the excessive pains which the Copper River Indians bestow upon the fashioning and caring for their bows. There are no first rate, tough, elastic woods near them. Birch and willow and such soft species are the only stock in trade. And yet, by dint of heating or toasting, boiling, greasing, and rubbing down they convert these poor materials into excellent arms."

 There is also a quote regarding Red Cedar that could have been written by someone on here.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 02, 2018, 12:51:42 pm
  I don't think so because the heavier arrow and longer draw will always have more KE. maybe ratio of KE to draw weight? The formula we have been using is supposed to equalize stored energy ratios.

or perhaps KE to Stored Energy?

I am still not sure that comparing a bow at 24, to a bow retillered to a different weight as it is drawn to 28 and retested at 24 tells us much. The way Leon did it seems more apples to apples, but maybe I don't understand the purpose of the experiment well.  In the opening post you described the operation of the experiment, but when I go back and re read I am not sure what the purpose is, could you clarify?
Title: Re: Request for those who are starting a new bow.
Post by: BowEd on May 02, 2018, 12:54:21 pm
Here's an interesting quote from Mason's book.

" Lieut. Allen, U. S. Army, has described the excessive pains which the Copper River Indians bestow upon the fashioning and caring for their bows. There are no first rate, tough, elastic woods near them. Birch and willow and such soft species are the only stock in trade. And yet, by dint of heating or toasting, boiling, greasing, and rubbing down they convert these poor materials into excellent arms."

 There is also a quote regarding Red Cedar that could have been written by someone on here.

I did say if not now but earlier some woods do like heat very well and perform unaffected and better than their natural state.Hickory from my experience.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 02, 2018, 01:16:18 pm
Here's an interesting quote from Mason's book.

" Lieut. Allen, U. S. Army, has described the excessive pains which the Copper River Indians bestow upon the fashioning and caring for their bows. There are no first rate, tough, elastic woods near them. Birch and willow and such soft species are the only stock in trade. And yet, by dint of heating or toasting, boiling, greasing, and rubbing down they convert these poor materials into excellent arms."

 There is also a quote regarding Red Cedar that could have been written by someone on here.

found the account of the copper river bow ok.  Can you point to your red cedar reading better? tribe? place? page? 
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 02, 2018, 01:26:08 pm
Here's an interesting quote from Mason's book.

" Lieut. Allen, U. S. Army, has described the excessive pains which the Copper River Indians bestow upon the fashioning and caring for their bows. There are no first rate, tough, elastic woods near them. Birch and willow and such soft species are the only stock in trade. And yet, by dint of heating or toasting, boiling, greasing, and rubbing down they convert these poor materials into excellent arms."

 There is also a quote regarding Red Cedar that could have been written by someone on here.

found the account of the copper river bow ok.  Can you point to your red cedar reading better? tribe? place? page?

 
    Part 4 of 7 Bows and arrows of various tribes etc.
"The constructive industry of the men was confined principally to the making of arms, bows, arrows, shields, and spears. These were all objects in which they took great pride. The favorite material for bows was bois d'arc (Maclura aurantiaca). When these could not be obtained hickory or coffee bean (Gymnocladus Canadensis) was used. The name ti-rak-is, bow, seem to indicate that bows were once made of bone, the ribs of the buffalo or other large animal, skillfully fitted and wrapped throughout with sinew. Forty years ago bows of this kind, and also of elk horn were occasionally found in use. Choice bows were some times made of red cedar, and if carefully used answered well, but were extremely liable to be shattered by any rough handling. The making of a good bow was a task involving long and painstaking labor. It was wrought into shape only a little at a time, being repeatedly oiled meanwhile, and constantly handled to keep the wood pliable. When finished the bow was sometimes wrapped with sinew and its strength thereby greatly increased. The string was of sinew from the back of the buffalo. As soon as the sinew was taken from the animal the par ticles of flesh adhering were scraped off and the minute fibres carefully separated. The best of these were selected and twisted into a string of uniform size and elasticity. One end of this string was fastened securely in place upon the bow, and the other furnished with a loop so adjusted that in an instant, as occasion required, the bow might be strung or unstrung.
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 02, 2018, 01:51:58 pm
Leonwood, were you using some sort of shooting machine?  I'm trying to figure out what's the best way to shoot right at 24" draw.  It seems it would be hard to get consistent results trying to eye a mark on the arrow. 
I don't want to build a shooting machine.  I would rather spend that time building another bow  ;D

No I just shot the arrows myself. I did put some tape on the shortest arrow and a black line on the others to know where tomdraw it to. This worked pretty good because I shot ten arrows at each  drawweight/length and the speeds where consistent within 5 fps with only one or two extremer ones which I ignored
Title: Re: Request for those who are starting a new bow.
Post by: sleek on May 02, 2018, 02:06:33 pm
Tie a steing between the handle and bow string that has 24 inches of slack, measured from the back of the handle. When you hit 24 inches of draw, the string gets tight and you let loose. Easy day.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 02:58:29 pm
  Willie as long as the arrow weight is proportionate it shouldn't make any difference if you retiller it. The level of performance is not supposed to change unless it takes set.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 02, 2018, 03:49:49 pm
Thanks Sleek for that tip.  Your explanation brings up a question that I've been meaning to ask.  How are we all measuring draw length for this test? 
I know this seems like an elementary question, but I was surprised to find out how many bowyers do their own thing when it comes to draw length.  Not that any one way is right or wrong, as long as you are consistent in measuring the shooter and projecting that to the bow you build. 
I go by AMO draw length.  Deepest part of the handle plus 1.75".     
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 02, 2018, 05:46:51 pm
I go to the back of the handle. My handles are usually 1 1/2". Close enough for me ;)
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 02, 2018, 05:58:24 pm
Ben, primitive is pretty much always weighed at the back of the bow but amo is 26 1/4 from the deepest part of the handle. That may have been what you meant.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 02, 2018, 08:38:23 pm
Yeah I would guess AMO isn’t based on primitive bows.  It’s just the way I saw to do it when I started building.  My handles are normally closer to 1.75”.  So if I just measure to the back the bow my draw measurement will be 1/4” different than DC’s.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 07, 2018, 08:18:24 am
I got the results at the first 24" and then tillered out to 28" and shot it through the chrono and I keep getting errors.  I'm using a black arrow on this second test as that was the only one that was close to the right weight.  Do you think the color of the arrow has anything to do with these errors? 
Title: Re: Request for those who are starting a new bow.
Post by: leonwood on May 07, 2018, 09:14:29 am
Should be easier for the sensor to "see" a black arrow, do you use it outside and with the white addons above the sensor? Make sure you shoot as straight as possible and not too close to the chrono. Whit my chrony it helps if I shoot a little low through the triangle but that might scare some people
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 07, 2018, 09:25:13 am
I think that an arrow that is spined a little light gives more errors. I seem to have less errors with a stiffer arrow. If it's bending a lot it will miss a sensor. Maybe stand back a little farther but that makes it tougher to hit the sweet spot.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 07, 2018, 09:37:13 am
I was working on this last night, so I was inside without the white add-ons.  I know outside in the day is better, but I was getting good consistent numbers with the 1st 24" test, which is why I'm confused.  The only thing different was the arrow. 
I'll switch it up and see if that makes a difference.  I'm wondering if the arrow was light spined now that you say that DC. 
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 07, 2018, 10:00:34 am
I rarely use the white covers. I found that they make no difference and I hit one of the wires once and exploded the thing. In a brighter location they may be handy. If they weren't necessary sometimes they wouldn't use them but the whole thing is way easier without them.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 07, 2018, 04:17:23 pm
Steve, I'm at 24"@40# on my next bow. Since my DL is 26.5" I don't want to go out to 28". If I just go to 27" what will change, divide by 27 instead of 28?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 07, 2018, 04:57:52 pm
Steve, I'm at 24"@40# on my next bow. Since my DL is 26.5" I don't want to go out to 28". If I just go to 27" what will change, divide by 27 instead of 28?

  Yes, that would be close enough, do you want to try it using both my formula and wood bears. I think his worked out closer on the last one. Mine is based on string travel rather than draw length.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 07, 2018, 05:39:11 pm
Sure,  what is Woodbears formula?
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 08, 2018, 08:27:30 am
I used a different arrow and was able to complete the test.  The bow is an ipe/yellowheart/bamboo R/D.  I was using a 14 strand FF string and carbon arrows. 

- 51#'s @ 24" - 436 grain arrow, 175 fps

- 56#'s @ 28"- 557 grain arrow, 173 fps

- 47#'s @ 24"- 405 grain arrow, 170 fps

The first 2 seemed pretty close is speed, but the last one was definitely slower.  I had to play around with my release to get consistent readings, so the numbers are realistically + or - 2 or 3 fps, but like I mentioned the last one was slower. 

Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 08, 2018, 08:34:51 am
And don't mind the luminated nock  :(.  I know it's not traditional but I had to pull out every piece of arrow making that I own to meet weight. 
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 10:48:37 am
Anybody know Woodbear's formula?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 11:02:36 am
Ben, that looks like a good test and is consistent with the tests I have done on pretty well made bows, it demonstrates the loss due to hysteresis that occurred during the last few inches of tillering. Good Job. 

  Dc,  Woodbear is 24/28     mine is 18/22  somewhere inbetween seems to work out best but I do think Woodbears is a bit closer than the one I was using.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 11:12:35 am
   Ben, if the formula was right on then your 28" shot would match your second 24" shot. I think my formula might be closer based on string travel. This would have also made your 1st 24" shot a bit faster for an even bigger difference.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on May 08, 2018, 11:50:52 am
Ben, that looks like a good test and is consistent with the tests I have done on pretty well made bows, it demonstrates the loss due to hysteresis that occurred during the last few inches of tillering. Good Job. 

  Dc,  Woodbear is 24/28     mine is 18/22  somewhere inbetween seems to work out best but I do think Woodbears is a bit closer than the one I was using.

Shoukd we do an average if the two formula? Add the two formula then devide by 2? So it would be 21/25.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 12:51:57 pm
OK 24/28 first
40#@24"=184fps   348grains  should be 342

40#@26.5=185fps   400grains   correct weight

33#@24"=180fps   294grains   should be 282


now 18/22
40#@24"=189  322 grains  should be 327

40#@26.5=185fps   400grains  correct weight

33#@24"=180fps  294grains  should be 270

I included as many numbers as I could think of so you could check my work. The bow is a Maple backed Yew with a bit of Perry reflex. This one didn't gain any reflex while tillering. It took about an inch of set but most of it happened in the first half of tillering, whatever that means.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 08, 2018, 01:37:52 pm
Ok y'all know backwards Tex. I did something a bit different. I tillered the bow to 24" . Usualy at this point there is very little tiller work left. The bow weighed in at 41.24 at 24".  I then pulled the bow to 26" .the bow weighed in at 45.94.  I then weighed the bow in at 24" again weight 40.76 so does this mean.48 loss due to whaaaat.  That should get you guys laughing for a bit. I have 5 bows that are at tiller stage . 4 Osage and one hickory. So call me badger and tell me better what you want. I could be some of the worst but that means I have more room for improvement.  I am having fun.
Arvin
Title: Re: Request for those who are starting a new bow.
Post by: avcase on May 08, 2018, 02:50:27 pm
This is an interesting thread. Ignore this if it has already been answered, but the only places on the bow that should be used to scale something based on draw length is the places where your hands touch the bow. The deepest part of the grip is a good point on the bow itself, and the point where the fingers connect to the string.

So, a 28” draw is really 26-1/4”.  A 24” draw is actually 22-1/4”.

Equivalent ggp at 24” draw is found by multiplying 10ggp by the ratio of (22-1/4) / (26-1/4”) = 8.48 ggp.

The logic in this:
Take an perfect design for 28” draw and scale it for 24” draw. The length of the 24” draw bow will be proportionally shorter, the brace height of the 24” bow will be proportionally a little less, and the amount of set of the 24” draw bow will be proportional to the draw length ratio also.

This may not work



Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 03:01:07 pm
Why not the power stroke like Steve is doing? That's what actually does the work.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 08, 2018, 03:14:56 pm
D.C. I just did that to See if it would change. It should work on any bow . I will test some of my finished bows and see if they change. Thinking out loud here D.C. If it does change then there has to be a cause. The dreaded H word maybe! Now what if anything can we do to change that number to even every time. Still thinking out loud. Arvin
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 08, 2018, 03:22:26 pm
Alan I was measuring from the throats of the nock to a women's hair tie at desired lengths on the arrrow. Measured to the back of the bow. That's as close to the same as I am capable of right now.
Arvin 
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 08, 2018, 04:25:06 pm
Thanks Badger.  I was wondering about why the last 24" shot was less.  It looks to be pretty consistent with the other numbers DC and Leonwood provided. 

And after reading avcase's response, it got me thinking.....Wouldn't you want to scale the power stroke ratio's? not the artificial 24" / 28" values? 
So the powerstroke of the bow is how much it is actually being pulled back, so if you use AMO draw length, and you have a 6" brace height throughout, the power stroke at 24" would be 24"-1.75"-6"= 16.25" ,  and at 28", 28"-1.75"-6"= 20.25".  Using this ratio, 16.25/20.25, you get .802 as opposed to 24/28 which is .857. 

5.5% different could be why we are dropping off in speed at the 2nd 24" test.  I guess that's what you were trying to tell me.  Sorry, I'm just picking this up. 


 
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 08, 2018, 04:40:28 pm
Quote
this mean.48 loss due to whaaaat.

Arvin, due to "permanently" compacting the cells when you drew it  to 26 for the first time. I would be happy with 1/2 lb loss over the last 2". I bet Steve doesn't do much better with his no set method.

permanently is in quotes because the bow may recover at rest unstrung some, so if you try the test tomorrow, you may see some of the same thing, but probably not as much as the full .48 lb.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 08, 2018, 04:46:46 pm
What is the end goal of this? Certainly everyone isn't going to start drawing their bows 24 inches and shooting underweight arrows to flatter speed.

 The bottom line is that the longer draw delivers more all around, even if the wood is broken down.  It's a net gain scenario.

Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 08, 2018, 04:53:36 pm
I would think Badger is trying to find a formula to level the playing field in the flight shooting world for people with different draw lengths.  Just a guess.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 08, 2018, 04:55:24 pm
Ben, I think that this test is a good overall comparision, but when it comes to splitting hairs, there are a few details that will "gotcha"

one is that the test assumes a straight  line force draw curve, so each inch in the powerstroke adds the same weight increase, but his is not always the case. more over the force draw curve can lie to us if the bow is stacking some at the end of the draw. the test really assumes that efficiency is the same through out the range of test draw lengths.

Put another way, this test may work well on a practical basis for two close  numbers, ie 24" & 26" & 28", but the formulas will all have problems if the spread is too much or the bow too short
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 05:58:03 pm
I got fairly different results for the two tests I did. The first one I pulled to 28" and probably got some set and the numbers kind of spread out. The second test I only wanted to pull to my draw length, 26.5". What surprised me was how close the first 24" pull was to the 28" pull. Granted I was using a lighter arrow but in a half-assed way that 4" didn't do much. It is possible that the whole test was designed around those two pulls and that's the reason they match.From what I gather the test was to hopefully level the playing field for short draw length archers. I don't think it got close enough to make everyone happy but then nothing does. I had been thinking the same as Alan with the scaled bow bow but that kind of lead nowhere except to make me think there is no way to level the field. Maybe if we measured the length of each archers elbow to fingertip(a Cubit)or some appropriate body part and use that to calibrate the scaling. ;)
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 06:33:19 pm
  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".
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 08, 2018, 07:08:02 pm
  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?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 07:30:53 pm
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.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 08, 2018, 07:37:51 pm
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.
Title: Re: Request for those who are starting a new bow.
Post by: avcase on May 08, 2018, 07:47:30 pm
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



Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 07:56:59 pm
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.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 08, 2018, 08:07:07 pm
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
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 08:14:35 pm
    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.
Title: Re: Request for those who are starting a new bow.
Post by: willie on May 08, 2018, 08:28:30 pm
Quote
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?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 08, 2018, 08:32:45 pm
Quote
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.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 09, 2018, 06:25:12 pm
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
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 09, 2018, 07:12:20 pm
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
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 09, 2018, 09:56:15 pm
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
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 10, 2018, 08:01:06 am
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.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 10, 2018, 08:08:42 am
You want force draw on these too?  Arvin
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 08:10:40 am
   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.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 10, 2018, 08:32:30 am
Will probably leave bow one as is Steve. The guy has 29.5 in. draw and gaps. I will monitor it as he shoots it this year. Oh and he is a south paw. Left handed bows are not my favorite bows cause I can't shoot them ! Arvin
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 11:54:52 am
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.

 I thought you'd already decided that it was 28"?
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 01:13:28 pm
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.

 I thought you'd already decided that it was 28"?

 Oh! Ok Pat, then I guess I don't know why I started the thread.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 02:03:50 pm
https://en.wikipedia.org/wiki/Confirmation_bias
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 02:23:52 pm
    Pat you seem to have a problem comprehending that things can have multiple reasons for having relevance . # 1. I wanted to show a relationship between set, longer draws and loss of efficiency. 2. I wanted to demonstrate instead of argue that a formula for leveling the playing field cannot really exist. 3. I was hoping this would be a more educational experience than simply winning an argument.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 02:40:41 pm
    Pat you seem to have a problem comprehending that things can have multiple reasons for having relevance . # 1. I wanted to show a relationship between set, longer draws and loss of efficiency. 2. I wanted to demonstrate instead of argue that a formula for leveling the playing field cannot really exist. 3. I was hoping this would be a more educational experience than simply winning an argument.

    But in a real world scenario number 1  apparently isn't really true.  Number 2 could be done but then it would be unrealistic to use in a real world scenario.

 I hope this was an educational experience  in that way.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 02:42:57 pm
 Pat #1 is true in the majority of bows made, it will always be true to some extent but hopefully as little as possible. A small sampling taken here is not necessarily representative of more typical results.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 02:50:13 pm
But not in a practical way.  I don't see how you expect that to change with more samples unless you hope a whole bunch of overbuilt hinged bows skew the data in your favor.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 03:07:06 pm
But not in a practical way.  I don't see how you expect that to change with more samples unless you hope a whole bunch of overbuilt hinged bows skew the data in your favor.

   On the contrary, very well built good performing bows will still demonstrate this. They won't be operating at their full potential.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 03:16:18 pm
  That IS their full potential in the real world. That's the whole point.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 03:28:44 pm
  That IS their full potential in the real world. That's the whole point.

  Not a point I am will to expect. Archery had a lot of areas of discovery when we first got in a few decades ago. A lot of good information had been lost or forgotten. I think in recent years the bowyers have reached a very high level of achievement and efficiency. New frontiers to go after are getting fewer and farther between and the gains are smaller when we find something. I see set and hysteresis as one of those new frontiers that can be studied in more depth for substantial gains. Thst just how I see it and even you can't argue about how someone sees something.
Title: Re: Request for those who are starting a new bow.
Post by: sleek on May 10, 2018, 03:39:32 pm
Pat, I imagine this is done in large part to illustrate a point to me about the formual I have been pushing. Im watching closely and enjoying this.  Im waiting to see more and do it myself before making a conclusion.  Thanks Steve. 

Pat, im sure there is a badgering jome to be made, but you sure are loud right now. Why?
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 10, 2018, 03:52:02 pm
It's not my place to argue, but I'm confused as to why this test is controversial.  I'm sure learning a lot.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 04:07:49 pm
  i don't think the test itself is controversial because it's only purpose is to demonstrate the potential loss of power we have in the later stages of the draw if not designed and tillered out properly. To some degree the formula being used is controversial only in that could it act as a formula to allow shorter draw bows to compete with longer draw bows on a level playing field. If someone does not accept the premise I guess that could also be considered controversial. 
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 05:17:50 pm
  That IS their full potential in the real world. That's the whole point.

  Not a point I am will to expect. Archery had a lot of areas of discovery when we first got in a few decades ago. A lot of good information had been lost or forgotten. I think in recent years the bowyers have reached a very high level of achievement and efficiency. New frontiers to go after are getting fewer and farther between and the gains are smaller when we find something. I see set and hysteresis as one of those new frontiers that can be studied in more depth for substantial gains. Thst just how I see it and even you can't argue about how someone sees something.

 That's all just rediscovery.  I'm not arguing about how you see it but how you are pushing it as already done and restricting things to try to arrive at your conclusion too soon.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 05:23:22 pm
Pat, I imagine this is done in large part to illustrate a point to me about the formual I have been pushing. Im watching closely and enjoying this.  Im waiting to see more and do it myself before making a conclusion.  Thanks Steve. 

Pat, im sure there is a badgering jome to be made, but you sure are loud right now. Why?

 I don't like tests skewed to give the "right" answer.   I have no objection to a formula for a level playing field as long as the field is open at both ends and the data is interpreted realistically.
 
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 05:33:39 pm
  That's my point Pat, how to interpret the data accurately. I have said all along a proper formula does not exist. Efficiency doesn't lie. If you want to go through the work of plotting a curve on a fresh 24" bow and then plotting it again at 28" and then plotting it again at the broke in bow shooting 24" you will see an obvious answer. I have done this many times. It is clear concise and consistent in favoring the fresh 24" draw bow. Now the only possible way for the 28" draw bow can have an increase in performance instead of decrease is if the design were changes while tillering out to 28". or the tiller shape was changed or the tips were lightened up etc. Lots of variable and it does require a large sample for meaningful results.

    On a personal note, if I thought you were actually trying to take this some place that would give us better information I would support you 100% but this thread and other threads you get involved in seem to be nothing but efforts on your part to discredit whoever it is you have a hard on for that day. Correct me if I am wrong here,
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 07:10:19 pm
 How so?  It's irrelevant unless you are going to shoot light arrows at 24". It doesn't matter if the bow lost performance at 24" as long as it has a net gain at 28 " or dare I say 30 ".

 On this thread and others I'm just trying to stall dogma from developing.

 But you sure can't be upset for shutting down a discussuion and then re-opening it.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 07:42:37 pm
Pat, I see the problem now. You don't seem to be comprehending the conversation. No one is argueing that a bow doesn't perform better at 28" draw. We are demonstrating that a loss of efficiency takes place in that last 4" in most cases. We are also demonstrating that if we attempted to handicap the bow using a different arrow weight the shorter draw would have a potential advantage. This same thing has been said over and over and over. If you fail to comprehend please don't keep badgering people with your version of what you think is happening here.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 08:03:05 pm
  Revisionist history.

  Even with the much lower GPP for the short draw  the advantage just isn't there. Especially if you actually put a regulation sized broadhead in the equation.   

 I'm also thinking people with actual short draws are going to be generally shooting proportionally shorter bows and so likely to be shooting bows equally broken down.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 10, 2018, 08:09:43 pm
 That is your opinion Pat but I have done extensive testing that says otherwise. It would all depend on the amount of handicap, wouldn't it? And then you follow up with another " opinion" about what people would be shooting. You are trolling Pat and I am filing a complaint against you if you don't come up with more specific genuine arguments. Allen Case and I challenge and disagree all the time but when we do we are specific about what we disagree on. You will have to do better than just what you think.  Inviting new bows to test on here was done to eliminate opinions and let everyone view a non biased test. So stop trolling or I am filing a complaint with the moderators. You have become a nuisance and boring! Please do better, I know you have it in you.
Title: Re: Request for those who are starting a new bow.
Post by: PatM on May 10, 2018, 08:55:46 pm
I never thought you would run to the teacher just because you weren't getting your way, Steve.
Title: Re: Request for those who are starting a new bow.
Post by: Selfbowman on May 10, 2018, 09:42:10 pm
Well I'll say. I am still waiting for info on my data. The test if I did it right has not been graded yet . Just to lighten the discussions a bit. I do think that there is something that I have learned here. You can figure your loss of efficiency that I did not see in my forse draw curve.and if it was present I did not See or understand it. I also understand that the grade is pretty useless once the bow is built. For me I see mass and try to place it as a builder . Many on here go at it from a mathmatics side which is great. They make most of the short cuts. Then there is the trial and erra guys like me. Which might make the smart duds stop maybe laugh and maybe think of a new angle. None the less I will continue the test for a while if  can find better arrows to match up. Arvin
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 11, 2018, 12:02:16 am
Well I'll say. I am still waiting for info on my data. The test if I did it right has not been graded yet . Just to lighten the discussions a bit. I do think that there is something that I have learned here. You can figure your loss of efficiency that I did not see in my forse draw curve.and if it was present I did not See or understand it. I also understand that the grade is pretty useless once the bow is built. For me I see mass and try to place it as a builder . Many on here go at it from a mathmatics side which is great. They make most of the short cuts. Then there is the trial and erra guys like me. Which might make the smart duds stop maybe laugh and maybe think of a new angle. None the less I will continue the test for a while if  can find better arrows to match up. Arvin

  Arvin, I couldn't come to any conclusions on yours. They appeared to be reflecting a bow that took no set at all after 24". Your test resembled a test of a bow that was already drawn to full draw or didn't take any set. I am hoping for several more samples over the next few weeks.

    The issue of handicapping short draw bows for broadhead is already settled so from this point on we are just looking at the effects of set. The two most useful numbers here are the comparisons between the two 24" draw tests one when fresh and the other after it had been tillered to 28". Of course the bottom line will always be the finished product. So as long as the 24" test is done with the same grains per pound it really doesn't matter much what is used 10 grains per pound would be fine.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 11, 2018, 12:06:23 am
  Pat, if getting my way means not putting up with someone just asking the same questions over and over then yes I hope I get my way. But don't despair they might find you in the right here and tell me to tone down. I would rather just not deal with you in any way in the future. You don't ask intelligent questions, you are not specific, you basically just harass people.
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 11, 2018, 01:19:31 pm
OK 24/28 first
40#@24"=184fps   348grains  should be 342

40#@26.5=185fps   400grains   correct weight  (later,May 11,40#@28"= 192fps)

33#@24"=180fps   294grains   should be 282


now 18/22
40#@24"=189  322 grains  should be 327

40#@26.5=185fps   400grains  correct weight

33#@24"=180fps  294grains  should be 270

I included as many numbers as I could think of so you could check my work. The bow is a Maple backed Yew with a bit of Perry reflex. This one didn't gain any reflex while tillering. It took about an inch of set but most of it happened in the first half of tillering, whatever that means.

I started taking pictures of this bow to post it and noticed that the bottom limb was way too stiff, looked awful. There was a bit more defex glued into the bottom limb but no, this needed fixing. 15 scrapes sorted it out and also brought the bow out to 40#@28". More in line with the test so I ran it through the chrono. At 10gpp(400grains) I got 192fps(My PB at 10ggp ;D ;D) Strangely the 24" draw weight didn't change.
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 11, 2018, 01:40:07 pm
  At 192 you have pretty much achieved about as close to perfection as you can get. That is smoking fast!  If you wanted to calibrate a formula to use on future bows of that same design you could simply find the arrow weight at 24" that matches your 28" speed. And then find out which formula will give you that. Each design of bow with different FDC's will use a slightly different formula, that's why I discount them as being of no real value.

   That bow would do extremely well at the flight shoots because it not only stores good energy but is also very efficient. I hope you can make it one of these years or find yourself a good shooter to represent you.
Title: Re: Request for those who are starting a new bow.
Post by: Bayou Ben on May 11, 2018, 01:41:46 pm
192 fps!  That's smoking

Yeah quit splicing those handles so you can come back down closer to my level... :D
Title: Re: Request for those who are starting a new bow.
Post by: Badger on May 11, 2018, 02:12:39 pm
  D/C  if you started using about 7.7grains per pound for that design at the 24" Mark I think it will give you a good prediction on potential
Title: Re: Request for those who are starting a new bow.
Post by: sleek on May 11, 2018, 02:47:26 pm
OK 24/28 first
40#@24"=184fps   348grains  should be 342

40#@26.5=185fps   400grains   correct weight  (later,May 11,40#@28"= 192fps)

33#@24"=180fps   294grains   should be 282


now 18/22
40#@24"=189  322 grains  should be 327

40#@26.5=185fps   400grains  correct weight

33#@24"=180fps  294grains  should be 270

I included as many numbers as I could think of so you could check my work. The bow is a Maple backed Yew with a bit of Perry reflex. This one didn't gain any reflex while tillering. It took about an inch of set but most of it happened in the first half of tillering, whatever that means.

I started taking pictures of this bow to post it and noticed that the bottom limb was way too stiff, looked awful. There was a bit more defex glued into the bottom limb but no, this needed fixing. 15 scrapes sorted it out and also brought the bow out to 40#@28". More in line with the test so I ran it through the chrono. At 10gpp(400grains) I got 192fps(My PB at 10ggp ;D ;D) Strangely the 24" draw weight didn't change.


I want all the bow dimensions to this please!  Also an unbraced pic from side and top?
Title: Re: Request for those who are starting a new bow.
Post by: DC on May 11, 2018, 03:54:48 pm
  D/C  if you started using about 7.7grains per pound for that design at the 24" Mark I think it will give you a good prediction on potential
I guess the next step is figuring out how to make light arrows. Haven't had much luck so far.