Primitive Archer

Main Discussion Area => Bows => Topic started by: DC on February 11, 2020, 07:49:49 pm

Title: Piking a recurve
Post by: DC on February 11, 2020, 07:49:49 pm
What happens when you pike a recurve? Let's assume you have 2" radius 90° hooks and the string lifts off right at full draw. Then you take an inch off each end and readjust the brace height. I'm thinking nothing will be different until the string lifts off but then my brain fails me. The hooks will no longer be 90° so the string lifts off sooner. Would this make a hump in the FDC or would it start to climb again? Would the DW go up? Any thoughts please?
Title: Re: Piking a recurve
Post by: Weylin on February 11, 2020, 08:15:03 pm
never thought about that. Interested in what people's thoughts are.
Title: Re: Piking a recurve
Post by: Santanasaur on February 11, 2020, 08:16:15 pm
Not sure but I am thinking this would  only change the string angle after liftoff.  Before liftoff angle is determined by the contact point on the bridge which hasn’t changed.
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 11, 2020, 09:07:33 pm
I did it some,,.as the profile changed,,,the bow shot slower
Title: Re: Piking a recurve
Post by: DC on February 11, 2020, 09:08:33 pm
Not sure but I am thinking this would  only change the string angle after liftoff.  Before liftoff angle is determined by the contact point on the bridge which hasn’t changed.
Yeah, I said that, but no bridge, a nice smooth radius.
Title: Re: Piking a recurve
Post by: DC on February 11, 2020, 09:09:48 pm
I did it some,,.as the profile changed,,,the bow shot slower
Brad, did you readjust the DW?
Title: Re: Piking a recurve
Post by: DC on February 11, 2020, 09:15:56 pm
Pike it, then just steam in the same recurves.
That wasn't the question. I'm wondering about "shortening" the recurve.
Title: Re: Piking a recurve
Post by: Russ on February 11, 2020, 09:17:21 pm
ohhh, Ok i getcha! sorry.
Title: Re: Piking a recurve
Post by: Santanasaur on February 11, 2020, 11:56:50 pm
I guess I added a bridge in my head. Now i think there will be a difference.

Like you said, when the original bow hits full draw it has just finished lifting off. Imagine adding 1” to the hook while drawn (now 118° of 2” radius hook.) That extra inch would not have lifted off yet, since it would be at a greater  angle to the string than the part that just lifted off.  So taking  away 1”  (now 61° of r=2” hook) should mean liftoff ends sooner because when the original bow is at full draw, that spot 1” below has already lifted off.

So I think the piked bow will finish lifting off sooner, but both will start lifting off together and otherwise have the same force draw curve up until the piked bow lifts off. (Because any tip beyond string contact is not participating)  After the point where the piked bow lifts off, I would  expect the piked f/d curve to take off more steeply than the original.
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 12, 2020, 02:29:43 am
DC,...I can't remember if I adjusted the weight,.just remember it was slower,.
Title: Re: Piking a recurve
Post by: Russ on February 12, 2020, 08:26:52 am
wait, are they static?
Title: Re: Piking a recurve
Post by: PatM on February 12, 2020, 09:24:18 am
I don't think you'll see a difference worth measuring except for the draw weight going up.  I think people attribute too many features of hooks and siyahs  closer to how a compound behaves.  It's just not that dramatic.
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 11:09:10 am
wait, are they static?
Yes
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 12, 2020, 11:27:01 am
I didnt take notes on that one,, and cant remember the details,, I was shooting through a chrono at the time,,I just remember the results were not positive,,that being said, I think it would depend on the bow,, or would vary depending on the bow,,,
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 11:40:27 am
I don't think you'll see a difference worth measuring except for the draw weight going up.  I think people attribute too many features of hooks and siyahs  closer to how a compound behaves.  It's just not that dramatic.
I'm not expecting a lot. I'm getting closer to 200fps and I'm looking for 1 or 2 fps gains. I'm finding that there is more change just from measuring errors/changes. I finished one yesterday that shot 194. That was 1 fps gain over my best. I shot it a few times and it was steady at 194. Then I remeasured the DW and found that it had lost a pound to 39. I dropped the weight of the arrow 10 gr and this time it shot 198. I was pumped. The next day the bow was back up to 40#. I trust my scale so I think it's the angle I'm looking at the string scale. It changes a bit depending on how much I want to bend over (lol) I know I'm being anal but inconsistencies like this bother me.
Title: Re: Piking a recurve
Post by: bassman on February 12, 2020, 11:47:07 am
40 lb bow shooting 194. What grain arrow are you shooting at what draw?
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 12, 2020, 12:06:09 pm
maybe go down to 2 strands,,  ;D
Title: Re: Piking a recurve
Post by: PatM on February 12, 2020, 12:09:49 pm
I don't think you'll see a difference worth measuring except for the draw weight going up.  I think people attribute too many features of hooks and siyahs  closer to how a compound behaves.  It's just not that dramatic.
I'm not expecting a lot. I'm getting closer to 200fps and I'm looking for 1 or 2 fps gains. I'm finding that there is more change just from measuring errors/changes. I finished one yesterday that shot 194. That was 1 fps gain over my best. I shot it a few times and it was steady at 194. Then I remeasured the DW and found that it had lost a pound to 39. I dropped the weight of the arrow 10 gr and this time it shot 198. I was pumped. The next day the bow was back up to 40#. I trust my scale so I think it's the angle I'm looking at the string scale. It changes a bit depending on how much I want to bend over (lol) I know I'm being anal but inconsistencies like this bother me.

 The one pound difference is the wood recovering overnight. An organic bow is always going to have those slight variables, however tiny.
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 12, 2020, 12:18:00 pm
so tomorrow it could go 200,,, :)
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 12:26:30 pm
40 lb bow shooting 194. What grain arrow are you shooting at what draw?
400 grains(10gpp)@ 28"

maybe go down to 2 strands,,  ;D
I'm at six now. Continuous loop. Minimum serving. Minimum twists. Don't think it can be much lighter. :D I just ran out of Fast Flight and had to replace it with D97. It seems a lot heavier so I'm going back and reusing the FF from older bows.

I don't think you'll see a difference worth measuring except for the draw weight going up.  I think people attribute too many features of hooks and siyahs  closer to how a compound behaves.  It's just not that dramatic.
I'm not expecting a lot. I'm getting closer to 200fps and I'm looking for 1 or 2 fps gains. I'm finding that there is more change just from measuring errors/changes. I finished one yesterday that shot 194. That was 1 fps gain over my best. I shot it a few times and it was steady at 194. Then I remeasured the DW and found that it had lost a pound to 39. I dropped the weight of the arrow 10 gr and this time it shot 198. I was pumped. The next day the bow was back up to 40#. I trust my scale so I think it's the angle I'm looking at the string scale. It changes a bit depending on how much I want to bend over (lol) I know I'm being anal but inconsistencies like this bother me.

 The one pound difference is the wood recovering overnight. An organic bow is always going to have those slight variables, however tiny.

It's funny that I could accept that when the bows were in the 170-180 range but now I'm getting close to the big number I'm starting to get picky ;D ;D I guess I should stop that ;D
so tomorrow it could go 200,,, :)

Yeah but only because the DW was over 40#
Title: Re: Piking a recurve
Post by: bassman on February 12, 2020, 12:35:16 pm
With those numbers you are quiet the builder.Good luck on your quest for 200 fps.
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 12:44:59 pm
With those numbers you are quiet the builder.Good luck on your quest for 200 fps.

Thanks, just standing on shoulders here :D
maybe go down to 2 strands,,  ;D

This needs a little more. When I first shot this bow it was with a Flemish D97 string that weighed 57 grains. It shot 193. Then I found the old FF continuous. It weighed 33 grains. Oh boy, I thought, this will help. It shot 194. 10grains of arrow equals 4 fps but 24 grains of string only equals 1 fps. Neither string has centre serving yet.
Title: Re: Piking a recurve
Post by: bradsmith2010 on February 12, 2020, 01:40:33 pm
your much closer to 200 than 100.. just call it 200 ;D
Title: Re: Piking a recurve
Post by: bassman on February 12, 2020, 01:50:10 pm
Glad you brought that up about endless loop,and Flemish twist. My findings are same as yours. On the Wall one bow maker was making claims of 10 fps increase with endless loop strings when compared to Flemish twist strings all else being equal.
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 01:53:23 pm
I evened out the dimensions of the recurves and tips(made the bigger match the smaller) and gained 1 fps. 5 in a row at 195. 195 is a milestone, right ;D
 Love this stuff ;D
Title: Re: Piking a recurve
Post by: DC on February 12, 2020, 02:26:29 pm
Glad you brought that up about endless loop,and Flemish twist. My findings are same as yours. On the Wall one bow maker was making claims of 10 fps increase with endless loop strings when compared to Flemish twist strings all else being equal.
That seems like quite a lot. The Flemish is heavier at the tips where the weight doesn't matter as much as at the centre so I don't see that there would be much diff. I've noticed that some bows respond more to removal of tip weight than others. No sure why.
Title: Re: Piking a recurve
Post by: artcher1 on February 12, 2020, 04:05:03 pm
I could see how an endless string could add 10# over a Flemish string. About 80-90% of the Flemish strings I see are made up using a counter-clockwise twist. But the individual strands themselves have a slight clock-wise twist. Makes a fellow wonder...…..Art
Title: Re: Piking a recurve
Post by: bassman on February 12, 2020, 09:47:04 pm
Archer 1 you mean 10 fps. If you have a chrony try it for your self, and post the results. That was not my findings at all. Tied properly one is as good as the other.Just another personal choice.
Title: Re: Piking a recurve
Post by: artcher1 on February 13, 2020, 04:43:41 am
Sorry, yeah, that should be 10FPS Bassman. A little slip of the finger there...…….

My chrony died of a bullet wound, can't draw a bow anymore, but there may be other ways to test the different string twist. Will post something if I find any difference...……..Art