Primitive Archer

Main Discussion Area => Bows => Topic started by: DC on February 06, 2018, 06:00:41 pm

Title: Big Hooks
Post by: DC on February 06, 2018, 06:00:41 pm
Just to double check something. In the picture there is a poor rendering of a recurve at full draw. You can see that the string never lifts off the end. Is the part of the recurve beyond the red line doing anything. Would it be better to cut it off to save weight on the tips. The red line might not be exactly in the right place by 1/2" or so.
Title: Re: Big Hooks
Post by: aaron on February 06, 2018, 07:05:47 pm
I don't think that the part past the red line would do anything when drawn as shown
Title: Re: Big Hooks
Post by: bradsmith2010 on February 06, 2018, 08:12:42 pm
+1 (-P
Title: Re: Big Hooks
Post by: PatM on February 06, 2018, 08:22:05 pm
I don't think that the part past the red line would do anything when drawn as shown

   How about on the front end of the draw? ;)
Title: Re: Big Hooks
Post by: bjrogg on February 06, 2018, 08:43:02 pm
Are you going to cut em off and tell us if there's any changes DC? (-P
Bjrogg
Title: Re: Big Hooks
Post by: aaron on February 06, 2018, 08:47:55 pm
I don't think that the part past the red line would do anything when drawn as shown

   How about on the front end of the draw? ;)
I think they would only contribute if it were drawn further.
Title: Re: Big Hooks
Post by: PatM on February 06, 2018, 08:51:39 pm
I don't think that the part past the red line would do anything when drawn as shown

   How about on the front end of the draw? ;)
I think they would only contribute if it were drawn further.

 Recurving doesn't influence the early draw then?
Title: Re: Big Hooks
Post by: DC on February 06, 2018, 10:20:49 pm
It influences the early draw by shortening the bow(string) doesn't it?
Title: Re: Big Hooks
Post by: DC on February 06, 2018, 10:25:21 pm
Are you going to cut em off and tell us if there's any changes DC? (-P
Bjrogg

On the little Yew I did it was 35# before and 38# after(approx). If I do this one I will chrono it at 27" draw before and after with 10 gpp arrows and also check draw weight before and after. This one is OS and the tiller is a tad iffy. It fought me tooth and nail.
Title: Re: Big Hooks
Post by: gutpile on February 07, 2018, 08:41:20 am
the additional wood added to make curve will definitely add more handshock than speed...actually will decrease speed... gut
Title: Re: Big Hooks
Post by: PatM on February 07, 2018, 08:49:58 am
    Definitely is a strong word.
Title: Re: Big Hooks
Post by: aaron on February 07, 2018, 08:53:08 am
I don't think that the part past the red line would do anything when drawn as shown

   How about on the front end of the draw? ;)
I think they would only contribute if it were drawn further.

 Recurving doesn't influence the early draw then?
Recurving does influence the early draw by making the bow feel shorter. When at brace, the bow "acts" like it is only as long as the distance between the string contact points. The ends of the recurves are past this point, so they don't affect the early draw.
Pat- are you messing with us? Why don't you tell us what you think?
Title: Re: Big Hooks
Post by: PatM on February 07, 2018, 09:24:11 am
Just questioning sweeping statements and making sure nothing is overlooked.

  The statement "the recurve feels shorter"   needs "feels heavier" added to it as well.

 The other statement about the wood beyond the contact point adding handshock could be countered with "would the handshock disappear if the bow was drawn until total lift-off occurred?"

 Do recurves typically have handshock if partially drawn?
Title: Re: Big Hooks
Post by: aaron on February 07, 2018, 09:42:21 am
Pat, yes, thank you . When I said "feel shorter" I should have included that this increases the early draw weight.
About the handshock- and the question "would hand shock disappear if the bow were drawn further?" If I understand it right , handshock would not disappear- it might even increase slightly because the tips would be traveling faster than if drawn partially. So, the handshock would be the same or worse, but the extra length of the recurve would have benefits independent of this. (string angle, further draw due to longer overall length of the bow) . Am I understanding this ?

Back to the question of weather cutting off the extra mass would reduce handshock- My gut says it would. Anything that decreases mass in a moving part of the limb should help if handshock is caused by the bow's mass "slamming back to brace" and imparting it's momentum to the hand. the amount it can shock your hand should be partly dependant on it's moving mass. f=ma? On the other hand, if you cut off the tips, there would be less mass but more tip speed, so the increased tip speed would possibly add to handshock, taking away some of the gains from less mass.

Reading this and other forums, handshock and it's causes don't seem to be as well understood as other aspects of bowyery

Title: Re: Big Hooks
Post by: aaron on February 07, 2018, 09:53:24 am
Are you going to cut em off and tell us if there's any changes DC? (-P
Bjrogg

On the little Yew I did it was 35# before and 38# after(approx). If I do this one I will chrono it at 27" draw before and after with 10 gpp arrows and also check draw weight before and after. This one is OS and the tiller is a tad iffy. It fought me tooth and nail.

This has me confused. Are you saying that you had a bow with geometry like the first diagram and you cut off a the part that never experienced lift-off and its draw weight increased??
Title: Re: Big Hooks
Post by: PatM on February 07, 2018, 09:59:41 am
  Piking increases draw weight.   A better question would be how did the F/D curve change by reducing the tips.

As far as the big hooks increasing early draw weight, picture if the hooks were made so that they could be quickly manipulated without changing any other factors. 

 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?
Title: Re: Big Hooks
Post by: Selfbowman on February 07, 2018, 10:38:26 am
Hmmmmm. I would say extra mass on ends will effect speed and shock. Always a trade off it seems to me. The only real thing we can count on is gravity. I like both recurves and long bows. The most efficient bow design I like is a mix of both. That's just a Texans point of view though. Arvin
Title: Re: Big Hooks
Post by: aaron on February 07, 2018, 10:42:16 am
I understand that shortening increases draw, and that lengthening would decrease it, but I thought this would only apply to areas of the limb that are not in contact with the string. In the drawing below, would bow 2 and 3 have the same FD curve? It seems to me they would. Would the bow with the very curly tips have a lower draw weight at any point than the bow with the more normally recurved ends? I don't see how it would.

If you could wind recurves tighter while keeping the bow strung, brace would increase and you would be shortening the distance between the contact points of the string at brace, so the draw weight would go up. Likewise if DC took the bow pictured at the beginning and steam bent the recurves back to a lesser curve, draw weight would decrease.  This seems different to what we are discussing because if DC were to cut off his recurve tips, he would also shorten the string and maintain equal brace height (I assume).
Title: Re: Big Hooks
Post by: DC on February 07, 2018, 10:45:56 am


 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?
If I'm following correctly that would change the brace height, yes?? I would be shortening the string so the brace height would be the same. I've been meaning to build a jig for my tree to aid making F/D curves so I'll do that. Is taking a measurement every 2" accurate enough? Coffee first, I just got up :D
Title: Re: Big Hooks
Post by: gfugal on February 07, 2018, 12:19:27 pm
  Piking increases draw weight.   A better question would be how did the F/D curve change by reducing the tips.

As far as the big hooks increasing early draw weight, picture if the hooks were made so that they could be quickly manipulated without changing any other factors. 

 If you could wind them a little tighter or back them off a bit with the bow strung, the string tension would certainly change, no?
But the string length doesn't change in those examples. So yes the extra length would theoretically pull the bow further, just like putting a string of similar length on a longer bow increases brace height. But if you pike it, and make a new string that effect shouldn't apply anymore.
Title: Re: Big Hooks
Post by: DC on February 07, 2018, 02:25:07 pm
OK the before 38#@27"
7"- 0
9"- 5
11"- 10
13"- 15
15"- 18
17"- 22
19"- 25
21"- 28
23"- 32
25"- 35
27"- 38

Chrono 173,176,185,179,179,183,179,190?,170?,183,175,178,178 Avg 178.9. I left out the two question marks

Now I'll cut the tips off.

After. I cut 3/4" off the tips and used a shorter string. For some reason when I got to the last hole in the pegboard I made to ensure consistent results I was only at  26 " draw so you'll have to keep that in mind. I haven't figured out what I did. I left the columns the same for consistency but remember they skew a bit and actually end at 26 not 27. crap.

After 37.5#@ 26
7"- 0
9"- 6
11"- 11
13"- 15
15"- 19
17"- 22
19"- 26
21"- 28
23"- 31.5
25"- 34
27"- 37.5

Chrono after 176,181,178,178,211?,177,180,184,178,186,183,175,174 Avg 179.1 Left out the iffy one again.

So I don't think I accomplished much. .2 fps doesn't mean squat. I wish I hadn't screwed up the FD but I can't go back. It didn't get worse though.
Title: Re: Big Hooks
Post by: aaron on February 08, 2018, 08:57:53 am
Looks to me like any changes were within a small margin of error. Bow stayed essentially the same.  Thanks DC for taking the time. PatM does this match your expectations? You seemed  to be hinting that it would  raise draw weight and possibly lower early  draw
Edited to change the word improve to lower in last sentence
Title: Re: Big Hooks
Post by: PatM on February 08, 2018, 09:30:38 am
I don't think the bow was changed enough to give us a meaningful comparison. I was under the impression that the beyond string contact point would be much larger and thus be a dramatic  enough difference to really highlight any changes.  As it is the results are kind of erratic.
      Can we see pics of the actual bow?
Title: Re: Big Hooks
Post by: aaron on February 08, 2018, 09:42:27 am
Im not sure I understand what you were expecting and why, PatM. Can you explain what you thought would happen (or what you think would happen if the hooks were even bigger (like in my sketch above with the super curly tips)?
Title: Re: Big Hooks
Post by: DC on February 08, 2018, 09:52:46 am
I found out what was causing my error as to draw length. When I built my peg board for doing FD curves I didn't remember that the scale gets longer as you pull it. As my peg board is below the scale it skews the numbers by close to an inch by the time I reach 40#. I have a fix in mind. Anyway I guess I didn't notice the draw length when I was doing the first run. So the end result is that the numbers should be directly comparable unless a there was a slight change in brace height caused by the new string . They are both slightly low as you get toward the full draw. So piking the bow in this case did slightly raise the early draw weight but it lowered the late draw weight. It looks like it didn't make a lot of difference though as the speed numbers show. I may have to build a machine for that.
Here's some pictures. The tiller is quite a bit off and there's a hinge on the right limb. I was hoping to gain a bit of weight to give me some working room. Like I said before this one really fought me. It may go in the corner of shame.
Title: Re: Big Hooks
Post by: PatM on February 08, 2018, 10:19:51 am
Im not sure I understand what you were expecting and why, PatM. Can you explain what you thought would happen (or what you think would happen if the hooks were even bigger (like in my sketch above with the super curly tips)?

 I would expect higher early draw weight with big hooks.  I don't care to speculate on your clockspring hooks.  That's too much exaggeration.
Title: Re: Big Hooks
Post by: DC on February 08, 2018, 10:58:41 am
Can we define big hooks? I'm thinking a big hook is one with a larger radius and a 90 degree bend. A larger radius will "shorten" the bow more at brace and that will increase the early draw weight. It will also "lengthen" the bow more at full draw which gives you more leverage which will lower the full draw weight. I put quotes there because it kind of depends which direction you're thinking from. Smaller radius lessens both of these. The angle of the bend controls lift off. I still think that anything past string lift off at full draw is wasted :D :D
Title: Re: Big Hooks
Post by: joachimM on February 09, 2018, 05:18:48 am
As long as the angle between string and nock is zero degrees at full draw, you have excess wood on your tips. This extra wood is not giving you any leverage, only excess mass.
So on your first drawing, you didn't remove enough wood.
And 2 fps means a lot in flight shooting, that's 5 m extra with a 10 gpp arrow.