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Main Boards => The Bowyer's Bench => Topic started by: arachnid on April 12, 2020, 03:37:08 PM

Title: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: arachnid on April 12, 2020, 03:37:08 PM: Hi guys.
Need some advice from you recurve experts.
I have a recurve design I want to improve but don't know how. So some guidelines will be helpful.
The bow is 64" long
Has a 19" riser with 23" power lam.
I use 0.003" taper in it.
Limb width is 1.5" (because the the glass I have).

Now here are the things i want to change:
First, I want to make is shorter- 60" or so.
The current design has some handshock- how do i get rid of it?
I want to make it draw smoother. I didn't do a FDC but the draw just doesn't "feel" smooth enough for a recurve.

These are the main issues I'd like to improve.
Any advice would be welcome
Thanks

(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/p720x720/92818475_2836240579798981_2642774333067362304_o.jpg?_nc_cat=101&_nc_sid=07e735&_nc_ohc=ohd2NnIc5JgAX-TtD_p&_nc_ht=scontent.fhfa2-2.fna&_nc_tp=6&oh=2d0f9e29cde8add3545ae0c27659cad0&oe=5EBA4EE5)

(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/93414244_2836240606465645_5710987502043529216_o.jpg?_nc_cat=102&_nc_sid=07e735&_nc_ohc=KOkCGxDDGEAAX_CBtnf&_nc_ht=scontent.fhfa2-2.fna&oh=0e3c2d6907649b92b2a9d57a253b2173&oe=5EB7FC48)

(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/93110484_2836240589798980_8546249951351406592_o.jpg?_nc_cat=107&_nc_sid=07e735&_nc_ohc=384OMwvaLQUAX8r85bk&_nc_ht=scontent.fhfa2-2.fna&oh=21293ef6fe297e01c7e3e680a0d54226&oe=5EBA25AA)
Title: Re: Advice needed on improving a recurve design
Post by: Crooked Stic on April 12, 2020, 04:22:38 PM: Just leave your hook the same and shorten the limb on the butt end. Go to a .001 taper with stable core.
Title: Re: Advice needed on improving a recurve design
Post by: Mad Max on April 12, 2020, 05:02:26 PM: Change the angle at the riser, go up about a inch at the nock. Don't change the limb curves , just the angle.
(https://i.imgur.com/HOFqeef.png?1)
Title: Re: Advice needed on improving a recurve design
Post by: Mad Max on April 12, 2020, 05:08:01 PM: For hand shock
Post a picture of the limb width, and how wide is it at the nock

Google recurve hand shock
Title: Re: Advice needed on improving a recurve design
Post by: Crooked Stic on April 12, 2020, 08:42:25 PM: You will be shortening the working limb going to 60 in. may help the vibration. With the .oo1 and limb side tapering you can get more performance also. And a bigger rounder hook. Get to crazy there tho and gonna need carbon to keep the limbs from going sideways.
Title: Re: Advice needed on improving a recurve design
Post by: buckeyebowhunter on April 12, 2020, 08:49:55 PM: For the handshock you can try more density in the riser by using a dymondwood or other laminated type wood. It will help absorb some of the vibration.
Title: Re: Advice needed on improving a recurve design
Post by: arachnid on April 13, 2020, 02:49:28 AM: Quote from: Crooked Stic on April 12, 2020, 08:42:25 PM
You will be shortening the working limb going to 60 in. may help the vibration. With the .oo1 and limb side tapering you can get more performance also. And a bigger rounder hook. Get to crazy there tho and gonna need carbon to keep the limbs from going sideways.

Side tapering like a pyramid taper or going parallel up to a point and the taper to the tips?
Title: Re: Advice needed on improving a recurve design
Post by: Crooked Stic on April 13, 2020, 08:24:47 AM: With the less lam taper or even parallel you gain stability. Then side taper to make your limbs bend where they work the best. I tried parallel but like .001 the best.
Title: Re: Advice needed on improving a recurve design
Post by: beachbowhunter on April 13, 2020, 09:27:11 AM: Quote from: Crooked Stic on April 12, 2020, 08:42:25 PM
You will be shortening the working limb going to 60 in. may help the vibration. With the .oo1 and limb side tapering you can get more performance also.

Would you maybe shorten the power lam or overall riser length to drop down to 60"?
Title: Re: Advice needed on improving a recurve design
Post by: arachnid on April 13, 2020, 11:04:21 AM: Quote from: beachbowhunter on April 13, 2020, 09:27:11 AM
Quote from: Crooked Stic on April 12, 2020, 08:42:25 PM
You will be shortening the working limb going to 60 in. may help the vibration. With the .oo1 and limb side tapering you can get more performance also.

Would you maybe shorten the power lam or overall riser length to drop down to 60"?

But that will give me, again, a longer working limb.. wouldn't the keep the hand shock?
Title: Re: Advice needed on improving a recurve design
Post by: Mad Max on April 14, 2020, 03:08:02 PM: 19" riser, 22" power lam, 19" working limb---22"+19"+19"=60"
Title: Re: Advice needed on improving a recurve design
Post by: arachnid on April 15, 2020, 02:51:10 PM: Quote from: Mad Max on April 14, 2020, 03:08:02 PM
19" riser, 22" power lam, 19" working limb---22"+19"+19"=60"

And that should be safe for a up to what draw length?
Title: Re: Advice needed on improving a recurve design
Post by: Mad Max on April 15, 2020, 03:14:29 PM: I have a 58" with 18-1/4" working limb, I don't see why it would not. It would do a 28" draw
Now you have 23" power lam and 20-1/2" working limb.
Title: Re: Advice needed on improving a recurve design
Post by: Crooked Stic on April 15, 2020, 04:43:04 PM: To find out do a FDC see where it stacks.
Title: Re: Advice needed on improving a recurve design
Post by: arachnid on May 20, 2020, 05:50:25 PM: So it`s been a while but I got to it and made the changes to my design.
I moved the limbs 1" forward, kept the same curve.
19" riser
22" power lam
switched to 0.001" taper

Here`s where I`m at now, after the bow it out of the form, roughly shaped, tillered and I also made a FDC.

This is the old design next to the new on:
(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/p720x720/98205239_2931581526931552_8786807324388884480_o.jpg?_nc_cat=103&_nc_sid=e007fa&_nc_ohc=E_5RxlrYx0wAX94V_5P&_nc_ht=scontent.fhfa2-2.fna&_nc_tp=6&oh=c44156a057e62868cdfc80872bcd611d&oe=5EEC7D92)

This is it on top of the new one (so you can see the difference in the limb angle)
(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/r270/p720x720/98306568_2931581696931535_6557560731867283456_o.jpg?_nc_cat=109&_nc_sid=e007fa&_nc_ohc=kSPkRh-FmMEAX8cU2kd&_nc_ht=scontent.fhfa2-2.fna&oh=d462220f91e3533d90978e9f09c9b7ab&oe=5EEB034F)

Here`s the new bow strung
(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/p720x720/98104041_2931581523598219_1686831861289975808_o.jpg?_nc_cat=108&_nc_sid=e007fa&_nc_ohc=KDPDNQaXGqgAX9Gomue&_nc_ht=scontent.fhfa2-2.fna&_nc_tp=6&oh=02d98c7349371123e6107a8b1a5766f2&oe=5EEC14C0)

Full draw 28" (I think it looks like the bottom limb is bending a bit more because of the camera angle. I checked the tiller and it`s even).
(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/s960x960/98135797_2931581496931555_182027860830060544_o.jpg?_nc_cat=111&_nc_sid=e007fa&_nc_ohc=n5-EHMtPnSAAX9NJJDD&_nc_ht=scontent.fhfa2-2.fna&_nc_tp=7&oh=22fa3363695f021b3fa88a14ab36a215&oe=5EED31A0)

And here`s the FDC
(https://scontent.fhfa2-2.fna.fbcdn.net/v/t1.0-9/100085075_2931581680264870_7640396869943689216_o.jpg?_nc_cat=105&_nc_sid=e007fa&_nc_ohc=nlEQz4JXH5EAX-qNzRR&_nc_ht=scontent.fhfa2-2.fna&oh=fa706294760bca054b72a78d622a711c&oe=5EE99B9F)

Now, I`m no expert by any means, but I think it looks pretty good. It draws smoothly up to 30" (currect me if I`m reading the FDC wrong).
As for hand shock- I`ll finish it and shoot it.

I`d like to know what do you guys think.
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: Mad Max on May 20, 2020, 08:49:08 PM: I think you made the right moves, looks awesome :thumbsup:

see the 5.18 at 30"--stacking
so your good to 29"
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: arachnid on May 21, 2020, 12:03:15 AM: Is it a common thing for a 60" recurve to stack at 30"?
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: Crooked Stic on May 21, 2020, 07:27:59 AM: One thing I see is you need to thin your fade ramp down quite a bit. Actually get it where it is flexing a bit. If you think about a TD with a 17 in. riser and wedges with a lot longer fade to fade that are still smooth to 30 in. Did you try going past 30 to see if it stays the same. You string angle still looks ok.
.
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: arachnid on May 21, 2020, 07:45:51 AM: Regarding the fades, I follow the rule of 1" from the end- 1/16" thick, 2" from the end- 1/8".

I might have a mistake in the measurement, but I'm pretty sure not.

One more thing is, I really want to know what the changes I did actually work? How does the taper change helped the smoothness etc....
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: Crooked Stic on May 21, 2020, 08:26:05 PM: The .oo1 taper keeps you limb stable in the hooks. Then you can play with your taper profile to make the limb bend different. Kinda weird that it hit the wall that bad at 30 in. seems it should gain more gradual.
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: arachnid on May 21, 2020, 11:10:43 PM: O uploaded the FDC to the bowyers group on Facebook and they said the same thing.
Some guys suggested I'll use more taper and a tip wedge
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: Crooked Stic on May 22, 2020, 08:39:23 AM: How is your width taper. taper all the way to the fade or back how far down the limb. This taper ca work the same as more forward taper and keep the core thicker for stability. Although with your gradual hook and stable core you can use .002 taper okay.
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: arachnid on May 22, 2020, 08:58:56 AM: Quote from: Crooked Stic on May 22, 2020, 08:39:23 AM
How is your width taper. taper all the way to the fade or back how far down the limb. This taper ca work the same as more forward taper and keep the core thicker for stability. Although with your gradual hook and stable core you can use .002 taper okay.

It's 1.5" wide, parallel up to about 10" from the tips and then tapers. Now the tips are 1" wide but I'll narrow them to 1/2" and check again.

Do you think 0.001" taper will benefit more from a pyramid width taper? Or should I keep it as is?
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: Crooked Stic on May 23, 2020, 07:51:25 AM: Not sure what a pyramid taper is.
Title: Re: Advice needed on improving a recurve design - EDIT: changes made, take a look😁
Post by: mmattockx on May 23, 2020, 10:51:17 AM: Quote from: Crooked Stic on May 23, 2020, 07:51:25 AM
Not sure what a pyramid taper is.

That's triangular back profile that has straight side to side tapers from the fades to the tip. It looks like a very elongated pyramid, hence the name.

A red oak pyramid bow I did this spring:
(https://i.imgur.com/RcbvWMA.jpg)

Mark