Sanity check of my possibly flawed logic.
I am trying to make a short 3 piece longbow that doesn't stack till 30 or as close to as possible. My current bow is 51" nock to nock. I have about 5 1/2" static tip. It has 001 back taper and parallel belly for cores. It starts stacking around 28-28.5". My thoughts are if I were to use a 002 taper instead of 001 on back lam it would cause the limb to bend more before levering the tips. If I used both parallels it would cause the tips to lever more quickly due to more resistance towards the fades.
Is my logic sound? I know you guys have a ton of experience out there
Thanks
If it's one piece your gonna need a short riser. A lot of deflex and a lot of reflex. I have built them with .004 taper per inch. Kinda like a Thunderchild.
Its a 3-piece
How about putting a little more recurve out on the limb ends.
Ya I was thinking that would help a little but want to make sure I keep it a longbow strung up I have a little room before it touches the limb.
I have built longbows 3P with a 12 in, riserdown to 54 in. you end up with not much of a sight window and must cant the bow. I am now building a 50 in. one piece recurve for 28 or less draw. Getting the longer draws out of short bows may be a problem to keep them durable.
Then you have theShrew Tsunami. With wider limbs. Then there is the Hoo-dini that's gotcarbon to keep it stable so who knows. Just depends on how much development you wanna do----
This might be a kirkl question. Im really bummed. I just ram it through the chrono and it only shot 140fps at 9.7gpp and 29" draw. I am wondering if there is too much deflex in my limb pads or ifI need more arc in my limbs. I would like to hit 175fps
Theres no recipe. And no offense to kirk but he is going to ask you about taper rates, stack makeup, pad angle, preload, hook properties, tip wedges and powerlams(which is all informaiton that exists on this forum which has a huge archive of really detailed and great information). But what does any of that mean to you. Im not trying to get ruffled feathers or anything but i mean how does changing the various thicknesses and taper rates along the bow limb change how the bow acts to you as a bowyer? Is it just factors or can you see how they physically influence the dynamic bow bending?
Kirk when you see this, i appreciate you dont get me wrong.
There's a ton of information out there on what taper rates do as a function of limb bending and how and what the influence of changing that parameter will do.
Quote from: Watsonjay on May 18, 2026, 02:27:36 PMSanity check of my possibly flawed logic.
I have about 5 1/2" static tip. It has 001 back taper and parallel belly for cores. It starts stacking around 28-28.5". My thoughts are if I were to use a 002 taper instead of 001 on back lam it would cause the limb to bend more before levering the tips. If I used both parallels it would cause the tips
So to help in some way after my rant. 001 back taper and parallel belly, total taper rate still 001 parallel doesnt matter. assuming thick side of taper is to bow center; If you want the entire limb to bend before the hooks start to lever you would remove the taper at all and have paralell laminations. This would make the lamination coming off the wedge the same thickness allowing the limb to more evenly distribute the bend amongst the whole limb. This would move the hook the furthest distance and would take the most energy to return to brace. If you increased the taper rate from .001 to .002-.004 then the difference in thickness from bow center to the hooks is even more dramatic, meaning that the part of the limb coming off the fade or wedge will be substantially thicker than at the tip. This limb will bend closer to the hook and resist bending near the wedge/fade/handle where due to the total taper rate is thicker ratio from center to tip than.
For getting your fps up the taper rates will help where the energy gets stored and what parts of the bow use up the energy while returning to brace, so adjusting for taper rates may not help you as much as a different design that incorporates preload.
Stacking has to do with the string angle reaching 90 degrees and the pull characteristics change. Having your limb bend further out and will change the point of rotation for for that string angle. also some good archived threads about stacking.
I have way less functional experience than the "authority" of my claims but im here to understand bows and this is what i think ive learned. Id love some discussion.
Quote from: dbeaver on May 19, 2026, 01:04:08 PMQuote from: Watsonjay on May 18, 2026, 02:27:36 PMSanity check of my possibly flawed logic.
I have about 5 1/2" static tip. It has 001 back taper and parallel belly for cores. It starts stacking around 28-28.5". My thoughts are if I were to use a 002 taper instead of 001 on back lam it would cause the limb to bend more before levering the tips. If I used both parallels it would cause the tips
So to help in some way after my rant. 001 back taper and parallel belly, total taper rate still 001 parallel doesnt matter. assuming thick side of taper is to bow center; If you want the entire limb to bend before the hooks start to lever you would remove the taper at all and have paralell laminations. This would make the lamination coming off the wedge the same thickness allowing the limb to more evenly distribute the bend amongst the whole limb. This would move the hook the furthest distance and would take the most energy to return to brace. If you increased the taper rate from .001 to .002-.004 then the difference in thickness from bow center to the hooks is even more dramatic, meaning that the part of the limb coming off the fade or wedge will be substantially thicker than at the tip. This limb will bend closer to the hook and resist bending near the wedge/fade/handle where due to the total taper rate is thicker ratio from center to tip than.
For getting your fps up the taper rates will help where the energy gets stored and what parts of the bow use up the energy while returning to brace, so adjusting for taper rates may not help you as much as a different design that incorporates preload.
Stacking has to do with the string angle reaching 90 degrees and the pull characteristics change. Having your limb bend further out and will change the point of rotation for for that string angle. also some good archived threads about stacking.
I have way less functional experience than the "authority" of my claims but im here to understand bows and this is what i think ive learned. Id love some discussion.
thank you, that helps a lot. Basically my logic was backwards.
My logic also says if I decrease my pad angle it will add more preload and speed??
It may, but thats where the fun comes in. Anyone wanna share one of their adjustable risers for watsonjay? Aluminum body adjustable pad angles and sometimes can be adjusted a few inches between say 16-20 inches(or whatever) depending how you construct
https://www.tradgang.com/tgsmf/index.php?topic=185947.0
Quote from: dbeaver on May 19, 2026, 01:34:28 PMIt may, but thats where the fun comes in. Anyone wanna share one of their adjustable risers for watsonjay? Aluminum body adjustable pad angles and sometimes can be adjusted a few inches between say 16-20 inches(or whatever) depending how you construct
https://www.tradgang.com/tgsmf/index.php?topic=185947.0
Ya, I am going to have make one of those.
I measured my limb pad angle and I am at 17deg. I think I will bump it down to 14deg and use parallels for the core to see what happens
It's a long process tinkering with different limb shapes, and adjusting limb pad angles to maximize preload. Along with shifting wedges and positioning working limb, and adjusting the length of the working limb.
But there is one more factor that really makes a difference in your performance that should be notet, and that is the limb travel... higher pre load , with a shorter limb travel makes a huge difference in performance .... I didn't quit tinkering until I was hitting high 190's at 10 gpp myself and over 200 fps at 9 gpp.
I was using .004 FT on my hybrid LB at first, but got better performance at .003 FT.
The most important thing to remember is that you need to dial in your pre load and limb shape at brace with your adjustable riser. Then mount it on your riser block before shaping the grip and measure back from the string to locate the deepest part of the grip.
Does anyone sell these adjustable limb pads riser? It would be nice to have an aluminum one like kirkl's
I made one from a old compound . Just cut off some of its limb and bolt yours on it. Use the compound weight adjustment bolt to change the angle.
Quote from: OldRawhide42 on May 21, 2026, 03:12:20 PMI made one from a old compound . Just cut off some of its limb and bolt yours on it. Use the compound weight adjustment bolt to change the angle.
Any pics of this? Hard to imagine.
Old compoumd
As of right now it goes 17° to 22°
Quote from: OldRawhide42 on May 21, 2026, 05:00:12 PMAs of right now it goes 17° to 22°
Pretty slick. Just an old compound. Usually they have really long risers. How do you adjust for riser length?
I dont
Quote from: OldRawhide42 on May 21, 2026, 04:56:45 PMOld compoumd
Well you should get some kind of award for redneck engineering on that set up... :biglaugh:
But.... I think i'd be concerned with lateral limb alignment issues using two different limb bolts like that. Once that limb bolt is adjusted out that far, your plus / minus tolerance on the threaded inserts alone in the riser is going to be all over the place. Then you have your location pin alignment too. :dunno: :dunno:
Jay... i sent you a PM.
Kirk the compound limb rocker keeps the lateral alignment pretty good. And ya the locator pins were a pain to do. I have shot it but it is not a fun bow to shoot. But it does help with the feel of the limbs . I mostly use it as a tool.
Jim
Alright guys, I am perplexed. I built another riser making it with 14 degree limb pads instead of 17. I put the limbs from the 17 onto the 14 and it bumped poundage up 4 lbs no surprise. The surprise is that after short drawing it to 28 to match the 51 from the other riser it shot the EXACT same speec 145 with 486gn arrow. I guess this means i need more reflex in my limbs? The unstrung pic is limbs on 17degree. The strung pic is on 14degree. And 2 risers side by side.
Did you measure the in line string tension on this one at brace? What draw weight @ 28" is it? Another question: how long is your string vs bow length tip notch to tip notch following the curve of the limb belly and measuring straight through the riser?
Something sounds off here. Those are very low numbers. You should be easily getting into the 170's or low 180's with that rig.
How have you got your chrono set up? Are you using a light kit indoors with a shooting machine? Or shooting by hand outdoors?
Quote from: Kirkll on May 24, 2026, 08:27:42 PMDid you measure the in line string tension on this one at brace? What draw weight @ 28" is it? Another question: how long is your string vs bow length tip notch to tip notch following the curve of the limb belly and measuring straight through the riser?
Something sounds off here. Those are very low numbers. You should be easily getting into the 170's or low 180's with that rig.
How have you got your chrono set up? Are you using a light kit indoors with a shooting machine? Or shooting by hand outdoors?
I don't have a way to measure the tension. It is 51@28" 486gn arrow 51" n2n. My string is 48" brace 7.25".
I ran it through my chrono with a new battery outside in the sun and got 144,145,145,144. I ran a compound through the chrono that always shoots 274 and it came up 274
Since it went up 5 lbs I could narrow the limbs or trap the back for lighter limbs. It just seems that changing it to 14 would have done something other than just add lbs
I would experiment with a longer string and lower brace ht. Believe it or not, that will increase the pre load weight first. Do this before narrowing the width profile and putting it on the shooting machine again.
If you want an accurate comparison, do a DFC chart on it going to 30" draw.
I will do the dfc for sure. On the first I am going to order a cheap small digital scale and rig up a couple short strings and a turnbuckle to measure tension. What should the tension be for good performance?
Quote from: Kirkll on May 25, 2026, 09:25:17 AMI would experiment with a longer string and lower brace ht. Believe it or not, that will increase the pre load weight first. Do this before narrowing the width profile and putting it on the shooting machine again.
If you want an accurate comparison, do a DFC chart on it going to 30" draw.
Not a lot of difference other than starting heavier and finishing heavier. Im guessing that means more tension on the string
Blue us 14 degree, Red is 17 Degree
That is a strange DFC chart and its hard to determine the draw length vs weight differences.
here is the industry stander form.
F:\2020 regroup\Bigfoot Order back up\DFC Charts\Copy of FD tables_blank template_new.xls
Here are a couple of my old DFC charts i did. these are on my hybrid long bow limbs.
John Paul Kelly Sas.xls
Thoms Sas.xls
Now look at the difference between this recurve DFC shape to my hybrid DFC charts. You'll notive the heavy weight on the first few inches of the draw, then it tapers off or lets off mid draw, then climbs again. This is a high preload bow that is about twice the string tension weigh as draw weight. About 100# on the in line scale at brace.
SasRC62.GIF
Quote from: Kirkll on May 26, 2026, 02:04:13 PMThat is a strange DFC chart and its hard to determine the draw length vs weight differences.
here is the industry stander form.
F:\2020 regroup\Bigfoot Order back up\DFC Charts\Copy of FD tables_blank template_new.xls
My bad. I was doing it in excel and didn't notice it changing the top row from inches to lbs. I'll redo it but I started at 11" and ended at 29"
Well it looks like I screwed up my attachment for the DFC chart template. I'll try again later today. I also have a quick video showing the contraption I built for my tiller tree that has a light panel spaced in one inch increments that makes your readings very accurate.
Kirk
Lets try this again. You put in your own info in the yellow boxes and the sheet is set up to calculate the data and give you a graph.
Copy of FD tables_blank template_new.xls
Quote from: Kirkll on May 26, 2026, 08:08:17 PMLets try this again. You put in your own info in the yellow boxes and the sheet is set up to calculate the data and give you a graph.
Copy of FD tables_blank template_new.xls
Shows up in Libre Office viewer on my phone should download and work on any device that has excel or Libre Office loaded.
Quote from: Longcruise on May 27, 2026, 12:12:17 PMQuote from: Kirkll on May 26, 2026, 08:08:17 PMLets try this again. You put in your own info in the yellow boxes and the sheet is set up to calculate the data and give you a graph.
Copy of FD tables_blank template_new.xls
Shows up in Libre Office viewer on my phone should download and work on any device that has excel or Libre Office loaded.
i had a tough time pulling it out of my hard drive back up files, and finding the right format to save it in before it would post on the forum. ".xls" seemed to work ok. I Just wanted to make sure others could open it. I haven't played with DFC charts in a long time, and don't do a lot of testing anymore. Thanks for letting me know. This universal DFC blank template should be placed in the sticky files at the top of this sub forum.
Here is a better chart should make more sense. I also glued up some different limbs with parallel cores, no tip wedges, and more reflex. In the pic I have them mounted on the 17degree riser and the old limbs on the 14. We will see how they do after profiling and tip overlay. Maybe too handle forward for the 14 degree riser. We will see if thus gets me more speed.
I also extended the limb wedges 1". I know a lot of changes at one but I don't have unlimited supplies.
Parallel core on a r/d longbow would have a lot of limb bending, possibly way too much at your wedge depends on geometry. Limb tips would also travel farther with the whole limb bending more and no tip wedge so the limb eats up some of the energy returning to brace. But try
Quote from: dbeaver on May 27, 2026, 08:27:33 PMParallel core on a r/d longbow would have a lot of limb bending, possibly way too much at your wedge depends on geometry. Limb tips would also travel farther with the whole limb bending more and no tip wedge so the limb eats up some of the energy returning to brace. But try
I know I was was having a stacking around 28.5" with 001 taper and it was suggested that parallels would stop the tips bending as much but I did have tip wedges in those. My goal is to get to at least 29" without stack. I wish I new of a book that explained dynamics of limb taper rates, reflex-deflex, wedges, limb shape, and the effects of changing each. Like a bow simulator. Change a shim length and simulate, change a limb shape then simulate.
If you want semi-guaranteed success then ask a bowyer with known results for a form template.
Youre making your own designs without a good grasp on the design elements wanting high end results and then wishing it were simpler. Its research and development or pay to play. You obviously have craftsmanship youre putting good looking bows together.
Quote from: dbeaver on May 27, 2026, 09:08:35 PMIf you want semi-guaranteed success then ask a bowyer with known results for a form template.
Youre making your own designs without a good grasp on the design elements wanting high end results and then wishing it were simpler. Its research and development or pay to play. You obviously have craftsmanship youre putting good looking bows together.
Ya there aren't a lot of 52" 3-piece long bow limb designs out there. I have a 52" once piece design from kennym that shoot good but only hits 140 fps @29" 45lb with my hunting arrow so I would like to design one that hits around 170 with my hunting arrows. N kennym's defense he designed it to be a 35lb kids bow.
I understand that's it takes experimenting on a new design I am hoping some of you more experienced builders will help point out possible improvements. I am willing to put in the work but yes I dont fully understand the dynamics. Right now I am paying to learn.
I would love to apprentice for a local builder but there aren't any by me
I would like to see a clear non lens distorted frontal view and side view of both of your limbs so far. They may not be working for you bilut it's an opportunity to play with them and see if you can do anything to improve your performance from there you can take anything that might be there to be learned that you can build understanding on.
It's a long process prototyping limb designs. One of the most important part is remembering that once you start getting where you want to be, & like the way the bow draws and shoots, you need to start splitting hairs to make improvements and gains. These come in little jumps in performance, and some of the best discoveries come by accident.
I learned about deep core narrow limbs being a key factor to performance gains by missing my poundage on a prototype by about 25# too heavy. Instead of throwing them in the wood stove, I took those things to the edge sander and took a full 1/2" off the width profile, and did an aggressive trap to the belly side. I was amazed with the jump it made. I went from 180 fps to 190 fps, but I found it was a wee bit squirrelly at the tips. So with this in mind, I logged all the details in my log book, then changed the taper rate from .004 to .003 and used a tip wedge. Every bow I built after that one I tested, and changed one thing at a time a wee bit. Just shifting the stop in the form an inch, or lengthening my butt wedges, all make a difference. Type of wedge material used makes a difference too.
I wasn't going to quit tinkering until I hit 200 fps @ 10 gpp arrow weight at 28" draw length. Brother... I'm telling you right now, that is a pretty high bar. The bowyers I was working with back then referred to that as "ringing the bell" and it's damn tough to pull off without using uni carbon and bias weave pre preg carbon for stability and still get any longevity and consistency. I spent about 10 grand on carbon alone trying to beat the fastest bow in the world's record. And I built some serious hot rods doing it too.... I did reach my goal,and It was a blast! But eventually they all blew up.
when you get right down to it, you need stability AND durability to sell custom bows.
And I drifted away from using so much carbon, and started tweaking my designs a bit here an$ there until I got damn near the same exact performance as the carbon bows, only they held up MUCH better, and were much more dependable. I did finally ring the bell with my static tip RC design using black glass, a combination of bamboo and maple cores on a few bows here and there, but the draw weights were 57-60 pounds, and I was drawing 30" to get those numbers.
There are no short cuts. Build em, test em very accurately, tweak them a bit, and log every tiny change you make. Once you get to the point you can get no more out of it, it's time to tweak the geometry of the limb, and start all over again with limb pad angles and preload first. Just One bow form will built a dozen different bows with a dozen different test results just shifting things in the form, experimenting with different limb lengths, changing wedge configurations, and taper rates. And limb pad angles.
Once you get a hundred under your belt you can put that bow on the tiller tree, stand back and look at it, and know exactly what it needs. You only get out, wha5 you put into these babies.... Kirk
Quote from: Kirkll on May 27, 2026, 02:08:30 PMQuote from: Longcruise on May 27, 2026, 12:12:17 PMQuote from: Kirkll on May 26, 2026, 08:08:17 PMLets try this again. You put in your own info in the yellow boxes and the sheet is set up to calculate the data and give you a graph.
Copy of FD tables_blank template_new.xls
Shows up in Libre Office viewer on my phone should download and work on any device that has excel or Libre Office loaded.
i had a tough time pulling it out of my hard drive back up files, and finding the right format to save it in before it would post on the forum. ".xls" seemed to work ok. I Just wanted to make sure others could open it. I haven't played with DFC charts in a long time, and don't do a lot of testing anymore. Thanks for letting me know. This universal DFC blank template should be placed in the sticky files at the top of this sub forum.
Well, sure - but exactly what needs to become a sticky: this entire thread or part of it? Email me about this so we can do it right.
Quote from: Watsonjay on May 27, 2026, 08:41:04 PMI wish I new of a book that explained dynamics of limb taper rates, reflex-deflex, wedges, limb shape, and the effects of changing each. Like a bow simulator. Change a shim length and simulate, change a limb shape then simulate.
VirtualBow will do that for you. It is free on the interwebz and there seems to be a reasonable number of users around. It's still time consuming to go through the near infinite combinations of variables, but it is way faster and cheaper than building a set of limbs every time to see what happens.
Mark
Quote from: mmattockx on May 28, 2026, 09:51:47 AMQuote from: Watsonjay on May 27, 2026, 08:41:04 PMI wish I new of a book that explained dynamics of limb taper rates, reflex-deflex, wedges, limb shape, and the effects of changing each. Like a bow simulator. Change a shim length and simulate, change a limb shape then simulate.
VirtualBow will do that for you. It is free on the interwebz and there seems to be a reasonable number of users around. It's still time consuming to go through the near infinite combinations of variables, but it is way faster and cheaper than building a set of limbs every time to see what happens.
Mark
I'm going to have to download that program and play with it some to see how close it is to real life experiences. Sometimes things look good on paper or in a simulation that don't come out so good in practical applications.
Quote from: Rob DiStefano on May 28, 2026, 06:36:21 AMQuote from: Kirkll on May 27, 2026, 02:08:30 PMQuote from: Longcruise on May 27, 2026, 12:12:17 PMQuote from: Kirkll on May 26, 2026, 08:08:17 PMLets try this again. You put in your own info in the yellow boxes and the sheet is set up to calculate the data and give you a graph.
Copy of FD tables_blank template_new.xls
Shows up in Libre Office viewer on my phone should download and work on any device that has excel or Libre Office loaded.
i had a tough time pulling it out of my hard drive back up files, and finding the right format to save it in before it would post on the forum. ".xls" seemed to work ok. I Just wanted to make sure others could open it. I haven't played with DFC charts in a long time, and don't do a lot of testing anymore. Thanks for letting me know. This universal DFC blank template should be placed in the sticky files at the top of this sub forum.
Well, sure - but exactly what needs to become a sticky: this entire thread or part of it? Email me about this so we can do it right.
We might want to just post the whole thread a rename it "Limb design discussions". There is a lot of good info, and good questions here, and it could be added to.
I can see a lot of things still yet to be discussed here.
I am going to try that program ans see if I can put these two limbs and risers in to see if it comes up with my results. Very curious. I plan on carving the nocks today and testing speed on this new limb. Tomorrow I am going to order a little scale to come up with a string tension rig. I found an old piston saying tension should be about double the draw weight for good performance. Cant wait to check these limbs
Quote from: mmattockx on May 28, 2026, 09:51:47 AMQuote from: Watsonjay on May 27, 2026, 08:41:04 PMI wish I new of a book that explained dynamics of limb taper rates, reflex-deflex, wedges, limb shape, and the effects of changing each. Like a bow simulator. Change a shim length and simulate, change a limb shape then simulate.
VirtualBow will do that for you. It is free on the interwebz and there seems to be a reasonable number of users around. It's still time consuming to go through the near infinite combinations of variables, but it is way faster and cheaper than building a set of limbs every time to see what happens.
Mark
I down loaded that program and tinkered with it a bit this am, and i think i would argue the part about it being way faster than building limbs. yes.... building air bows on a screen will be cheaper than materials used in prototyping, but nothing will replace the tiller tree and actually shooting and testing the bow.....
You are going to end up wasting a lot of screen time only to find out its just another rabbit hole....and you are still going to have to tweak your prototypes.
Reminds me of the photos you see of a big construction project with all the owners, the Architect, and all the engineers standing around the old carpenter in the center with saw dust in his hair & a pencil behind his ear explaining to these guys why these plans are not going to work, and what changes need to be made to make it come together... I've been in that position many times over the years, and building bows isn't any different. Nothing trumps hands on experience.
I think what would help me the most with it is to put a current limb in there and make a little change like wedge length and see what changes to save me from going down that road if there doesn't look like there will be much improvement and focus on another tactic that looks like it has better odds of improvement
Well the 2nd set of limbs is done enough. I always end up with tip twist that I have to fix and I have to process how to fix it in my head. The new limbs on the 17 degree riser hit 158 but new limbs are currently 55lb on it but old limbs on 14degree riser were 55 and only hit 145 so I think it's an improvement. I'll attach the dfc and pics of old and new limbs. The new limbs on the 17 degree see to pickup some poundage in the middle of the cycle??
I broke up the dfc charts into the 2 different limbs on the same risers 14deg and 17. The second limbs seem to help with stacking from 28"-29". Because I changed 4 features (1" longer butt wedge, additional reflex, parallel cores instead of 001ft, and no tip wedge) I am not sure what helped but am guessing it was the parallels?? The 17 seemed to have more of an issue with stacking than 14deg. Speed with 17deg went from 140 to 158 but poundage is up 4 pounds too. The 14 degree went from 145 to 160 but poundage was higher too
Quote from: Watsonjay on May 27, 2026, 09:34:27 PMQuote from: dbeaver on May 27, 2026, 09:08:35 PMIf you want semi-guaranteed success then ask a bowyer with known results for a form template.
Youre making your own designs without a good grasp on the design elements wanting high end results and then wishing it were simpler. Its research and development or pay to play. You obviously have craftsmanship youre putting good looking bows together.
Ya there aren't a lot of 52" 3-piece long bow limb designs out there. I have a 52" once piece design from kennym that shoot good but only hits 140 fps @29" 45lb with my hunting arrow so I would like to design one that hits around 170 with my hunting arrows. N kennym's defense he designed it to be a 35lb kids bow.
I understand that's it takes experimenting on a new design I am hoping some of you more experienced builders will help point out possible improvements. I am willing to put in the work but yes I dont fully understand the dynamics. Right now I am paying to learn.
I would love to apprentice for a local builder but there aren't any by me
When you are testing your bows and trying to improve performance. You need to use a shooting machine and very precise arrow weight at 10 gpp and 9 gpp. into the equation. Just saying that you were using your hunting arrows, doesn't tell us anything. You also need Exact draw length comparison that the shooting machine provides. Indoor light kits for the chronograph in a controlled environment without any fluorescent light fixtures is a must too. Those chronographs can be all over the place using them outdoors or in weird lighting. When I was getting serious about it I used two chronographs in tandem because I didn't trust just one.
Can you post some full draw photos of each limb at 28-30" draw? And give a detailed description of your wedge length and taper rate? It's tough to advise without seeing it bending.
I can get one of my kids to take a pic while I pull on my draw board.
I used 8" long wedges tapering from 3.75" down to 0 and the wedges are .35 thick. The the three pics are 7.25" brace, 28", and 30". I never intended it to go to 30" being that short of a bow. These are the 2nd limbs
This is the first set of limbs. With tip wedges, and a 7" butt wedge same thickness. I actually like the way this looks bending more, not at stiff by wedge.
Pics
How about 2 more with no string and both the limbs on balanced on the tiller tree.
Here is my 52" one piece r/d longbow at 29" draw. 54 @ 29" 10 gpp (540 grains) 188 fps. 9 gpp 196 fps. Look at the string angle. This one was jumping up over 3# per inch from 29-30". Never did run a DFC chart on this one. But I hunted elk with it for 2 years.
After I got my shooting form dialed in, and my alignment good, my draw length went to 30". This baby didn't hold up very long shooting 30". She's now a wall hanger.
yeti5_Original.jpg
Here are a few more photos. Keep in mind this was an early prototype and the fades were way too steep on this riser. As I moved forward with this design, I lengthened the fades and got a much better transition. That is where this bow eventually failed was in the fade section shooting 30" draw.
IMG_6785_Original.jpgIMG_6780_Original.jpgIMG_6784_Original.jpgIMG_6783_Original.jpgIMG_6781_Original.jpg
That is a long flat spot along the limb. It looks like the strings had been touching the limbs. Can you explain the features that allowed you to get that performance and that low string angle at 29". It looks like the was a decent amount of deflex with the limbs behind the riser and the tips don't look like they were really in front of the riser. I thought you wanted your tips ahead of the riser for better cast, I know not too much or things het unstable?
Thank you for sharing.
I'm glad you noticed the flat spot Jay. There is just something about that is special.
I know it's not on the tiller tree, but you can see where that limb is bending at full draw, and further more, how FAR the limbs are traveling. Not very damn far. Look at the difference between the distance from the deepest part of the grip to the straight edge, and the distance of brace height at 7". The string was only 2.25" shorter than the NTN length . 52" NTN. 49.75" string. I can't tell you what the string tension at brace was because that was before I got into testing that. What I can tell you was that it had a Lot of preload. It also had .003 FT and 6" tip wedges I also believe I was using power lams coming up the belly ramps to extend the fades a bit on that 16" riser.
With this in mind..... You may want to try an experiment with your existing limbs, and build a mock up riser from oak or some other cheap hardwood that pushes the deepest part of your grip forward. Then play with your limb pad anngles, and use a longer string.
I honestly prefer the flat spot in the limbs with the reflex closer to the tips myself. This gives you a deeper core thickness in the working section and allows a faster taper rate and lighter weight tip. The width profile on mine is only 1.20" to 1/2" wide at the tip notches.
I reread your reply and wanted to comment on your definition of deflex. Due to the short length of this bow I angled the flat spot to the belly side. There really isn't a de flex sweep to my design. Instead of using an elliptical shape in that outer portion of the limb get the reflex, I flipped the tips and kept them static with a tip wedge.
I use this flat spot in my Sasquatch hybrid design too, but because of the extra length I straightened out the flat spot to increase preload a5 60" length.
Look at this build album and the shape of the limb and position they are in before brace height..... these bows will draw 33 inches without stacking, and get incredible performance in the 50-55# draw weights. Below 50 pounds the preload lessons and not as much energy can be transferred to the shafts.
https://photos.app.goo.gl/9Je82UHTrGkZpnEF8
Here is another unstrung photo
https://photos.app.goo.gl/LuC8C2VcXWkoiV1P7
Quote from: Kirkll on May 29, 2026, 07:48:12 PMI'm glad you noticed the flat spot Jay. There is just something about that is special.
I know it's not on the tiller tree, but you can see where that limb is bending at full draw, and further more, how FAR the limbs are traveling. Not very damn far. Look at the difference between the distance from the deepest part of the grip to the straight edge, and the distance of brace height at 7". The string was only 2.25" shorter than the NTN length . 52" NTN. 49.75" string. I can't tell you what the string tension at brace was because that was before I got into testing that. What I can tell you was that it had a Lot of preload. It also had .003 FT and 6" tip wedges I also believe I was using power lams coming up the belly ramps to extend the fades a bit on that 16" riser.
With this in mind..... You may want to try an experiment with your existing limbs, and build a mock up riser from oak or some other cheap hardwood that pushes the deepest part of your grip forward. Then play with your limb pad anngles, and use a longer string.
I honestly prefer the flat spot in the limbs with the reflex closer to the tips myself. This gives you a deeper core thickness in the working section and allows a faster taper rate and lighter weight tip. The width profile on mine is only 1.20" to 1/2" wide at the tip notches.
It seems like moving the grip further forward would lose some of the power stroke and stored energy?? Correct? But maybe that is why the string angle was so low because it was drawing like a 26-27"?? Sounds like a forward handle bow with straight limbs and a decent amount of static reflex at the tips a good taper to make the tips act like a recurve snap is the secret sauce.
Damn.... I just lost a long winded post here with this new security protocol in place typing on my iPad. I'm going to wait until I get on my pc and do my typing in a word program and paste it into the forum now.... Chit.... :banghead: :banghead: :banghead:
I know better.
The short version is you need a different perspective on the forward riser placement.
You are adding 2" to your draw length before stacking doing this... give that some thought. To be continued....
Quote from: Kirkll on May 28, 2026, 12:40:17 PMI down loaded that program and tinkered with it a bit this am, and i think i would argue the part about it being way faster than building limbs. yes.... building air bows on a screen will be cheaper than materials used in prototyping, but nothing will replace the tiller tree and actually shooting and testing the bow.....
You're using it for the wrong thing and you only see a rabbit hole because you're used to building and testing to see what happens the old fashioned way.
What it is good for is seeing how trends go and what effects changes have to the bend or draw weight or string tension at brace. This is extremely valuable for newcomers who don't have your depth of experience and don't want to spend years getting it.
We see draw weight questions all the time from people trying something new. Well, the software will get you right in the ballpark on the first try compared to asking people what weight they think a new bow design will be based on taper rates and stack thicknesses.
Yes, you absolutely have to build and test bows as well. But once you've validated the analysis results to real bows then you don't have to build nearly as many bows to test new ideas with.
Mark
Quote from: Kirkll on May 30, 2026, 11:11:00 AMThe short version is you need a different perspective on the forward riser placement.
You are adding 2" to your draw length before stacking doing this... give that some thought. To be continued....
That's pretty much what I said. You lose power stroke but gain in longer distance before stacking. That is really good if you want to prevent stacking on a short bow with a longer draw. Seems like for that design to be efficient you needed to build a limb that would produce the energy storage a lot sooner as you effectively have a shorter draw stroke. It sounds like you did that. I am guessing it has to do with that flat spot. You definitely have me thinking about how limbs work. Thank you.
Quote from: Kirkll on May 30, 2026, 11:08:51 AMDamn.... I just lost a long winded post here with this new security protocol in place typing on my iPad. I'm going to wait until I get on my pc and do my typing in a word program and paste it into the forum now.... Chit.... :banghead: :banghead: :banghead:
I know better.
Ya. I've learned to copy before I hit post. The price of security.
Quote from: mmattockx on May 30, 2026, 11:17:21 AMQuote from: Kirkll on May 28, 2026, 12:40:17 PMI down loaded that program and tinkered with it a bit this am, and i think i would argue the part about it being way faster than building limbs. yes.... building air bows on a screen will be cheaper than materials used in prototyping, but nothing will replace the tiller tree and actually shooting and testing the bow.....
You're using it for the wrong thing and you only see a rabbit hole because you're used to building and testing to see what happens the old fashioned way.
What it is good for is seeing how trends go and what effects changes have to the bend or draw weight or string tension at brace. This is extremely valuable for newcomers who don't have your depth of experience and don't want to spend years getting it.
We see draw weight questions all the time from people trying something new. Well, the software will get you right in the ballpark on the first try compared to asking people what weight they think a new bow design will be based on taper rates and stack thicknesses.
Yes, you absolutely have to build and test bows as well. But once you've validated the analysis results to real bows then you don't have to build nearly as many bows to test new ideas with.
Mark
Sounds exactly like a lot the engineers perspectives i've worked with over the years. But its "The carpenters perspective" that validates, or invalidates the data, and in many cases the engineering calcs do not factor in lateral and vertical stability issues with a bow, much less stacking issues at various draw lengths.
Case in point is that according to super tiller calcs a symetrical deflex sweep stores more energy with a thinner limb thickness than an elliptical shape . So therefore it stands to reason it should be higher in performance having less mass weight in the limb. And "You cant argue with the math." I tell the engineer i'm not arguing about the math, or your calcs, i'm showing you the practical application, and THAT sucks!
You are right about having many ways to skin a cat. If you are seriously into cad and different programs that simulate building air bows. that's cool. have at it. In my opinion that's wasting time. I build real bows and did my prototyping the old fashion way. There is nothing that replaces experience and time invested in accurate testing.
Here are a few different limb shapes with the same amount of reflex in the limbs. How would you plug this into the virtual bow program ,and what are the characteristic differences? you need to keep all the taper rates at.003, but the top limb has a 7" wedge 3/8" to nothing in 4" with a flat top. the center one has a 10" wedge milled .30 to nothing in 12" and finished wedge at 10", and the bottom one has the same .30-0 wedge 11" finished length. And... all of the limbs have tip 8" tip wedges milled from.050-0 and drop 6" below the tip notches.
limb design 1.gif
Quote from: Kirkll on May 31, 2026, 01:48:25 PMHere are a few different limb shapes with the same amount of reflex in the limbs. How would you plug this into the virtual bow program ,and what are the characteristic differences? you need to keep all the taper rates at.003, but the top limb has a 7" wedge 3/8" to nothing in 4" with a flat top. the center one has a 10" wedge milled .30 to nothing in 12" and finished wedge at 10", and the bottom one has the same .30-0 wedge 11" finished length. And... all of the limbs have tip 8" tip wedges milled from.050-0 and drop 6" below the tip notches.
limb design 1.gif
In your experience which one would produce the best performance while still providing good stability? I am guessing the middle one. How would you predict these limbs behaving at string up and when being drawn? Would you expect the bottom one to bend more at the wedge and straight part because it isnt an arc at stringup? Wouldn't the bottom limb wedge have to be at the same angle as the other two to really show reflex as it would put the tip way further forward ahead of the handle on the same riser? Or am I misunderstanding the term reflex? Thank you.
Ive beed thinking about this more. The energy to cast an arrow is based on the act of putting tension and compression on a material making it want to return back to a more neutral state right or its original glued up position. On the last limb just to get it to brace because it is far ahead of the butt wedge it seems like it would increase tension and compression more than the others to get it to the same brace, but since the limb is so straight and most of the bend is right by the wedge it seems like all the tension and compression would be in that little spot versus spread evenly over a limb with more arch making that a high stress point??
To answer this properly I need to be on my laptop so I can type it in a word program, then bring it in and post it. The security protocol now has a time out on it. If you take too long typing before posting it, you loose it.
Kirk
Keep something in mind that is hugely important. Performance as pertains to speed and kinetic energy from the arrow is the result of HOW MUCH ENERY IS TRANFERED to the shaft, not how much energy storage the limb has. The keys to a higher transfer is the preload tension at brace, mass weight in the tips of the limbs, and limb travel.
Of course you need good energy storage to pull that off too. I'll give you a hint... deep core, narrow limb profile is the ticket. Better stability, Less wind resistance , and lighter mass weight.
Take a set of your limbs and narrow them up skinny as a whip, then match up some arrows at 9-10 gpp at the new draw weight. I think you'll be amazed.
Btw... the bottom two shapes in my drawing will out perform the top one.
The bottom limb has the wedge being pressed into a reflex position putting it in the form. This really adds strength to that fade area, but due to its location at the last 2" of the fades, it works as an overload spring. As the working portion starts maxing out on compression and energy storage, the fades start flexing a bit without causing a hinge effect. I get incredible performance out of this design, and can draw to 33" on a 60" bow without stacking.
Kirk on your lower limb picture do you use a higher limb pad angle than on the middle one ???
Quote from: OldRawhide42 on June 01, 2026, 09:23:10 PMKirk on your lower limb picture do you use a higher limb pad angle than on the middle one ???
Yes... I actually have two different risers for that limb design. My original had a 22 degree limb pad angle. Then after I designed my Sasquatch SS static tip RC with a 17 degree limb pad angle, I built another form for my hybrid long bow limbs that matched the riser. The original has the deepest part of the grip further forward, than the SS riser. But I can put both longbow limbs and RC limbs on the same riser now. I often have customers that want both designs on the same riser and I build extra limbs.
Quote from: Kirkll on June 01, 2026, 08:23:16 PMThe bottom limb has the wedge being pressed into a reflex position putting it in the form. This really adds strength to that fade area, but due to its location at the last 2" of the fades, it works as an overload spring. As the working portion starts maxing out on compression and energy storage, the fades start flexing a bit without causing a hinge effect. I get incredible performance out of this design, and can draw to 33" on a 60" bow without stacking.
So you actually bend the wedge at glue up?? That is pretty cool.
Here are a few pictures showing what these limbs do at brace and full draw. Take note of the string angle* This is a 29" draw. also take note of the fade tips starting to flatten out a bit with the reflexed wedge tips. i could draw this bow another 4 inches before it stacks.
IMG_4269 (1).jpg
IMG_4252.jpg
IMG_4253.jpg
here is one more showing width profile. These are 1 3/8" to 9/16" at the tips. I've gone down to 1.25" to 1/2" tips too.
IMG_4302.jpg
How long is that bow? If I were to do the same on a 52" bow how long before you think mine would stack. I guess I accidentally did my limb like yours other than the reflexed fade. I may try that too.
Th limbs I currently have arre 1.5" (the 2nd set) I started my profile 1" after fade and went down to 1/2" at nocks then tried to blend the profile to the fade a little so less obvious
Heres an example of what this thread looks like,
Watsoinjay: tell me how to do this!
Kirk: heres what i do.
watsonjay: will that work for me
Kirk: heres what i do.
Cant believe this is stickied at the top of the page.
Quote from: dbeaver on June 03, 2026, 07:46:19 AMHeres an example of what this thread looks like,
Watsoinjay: tell me how to do this!
Kirk: heres what i do.
watsonjay: will that work for me
Kirk: heres what i do.
Cant believe this is stickied at the top of the page.
I know, I really appreciate kirkl sharing his theories and experience. I cant make others share their theories but I appreciate anyone willing to.
Even if it wasn't pinned it would be at the top of the page right under the pins as we are actively contributing.
Quote from: dbeaver on June 03, 2026, 07:46:19 AMHeres an example of what this thread looks like,
Watsoinjay: tell me how to do this!
Kirk: heres what i do.
watsonjay: will that work for me
Kirk: heres what i do.
Cant believe this is stickied at the top of the page.
Feel free to contribute something about limb design beav. There are others here that have posted about using software programs that simulate different designs, but haven't shown any examples. I'd be curious to hear what that program shows on the above drawings I've provided.
This isn't about me, or my bows. This is about helping others by sharing my experience and showing results first hand. If you don't appreciate my efforts, or disagree with what I have to offer. Please feel free to offer your own experience.
As to your question Jay, with the 52" length you are not going to get those 33" draw lengths, but 30" can be accomplished. I posted photos of an early prototype 52" one pc bow showing a similar limb design, but if you look at the bow up against the straight edge, you'll notice how I angled the flat spot in the limb to the belly side using a steeper limb pad angle.
The above bow length I just posted was 60".
Quote from: Kirkll on June 03, 2026, 11:01:04 AMQuote from: dbeaver on June 03, 2026, 07:46:19 AMHeres an example of what this thread looks like,
Watsoinjay: tell me how to do this!
Kirk: heres what i do.
watsonjay: will that work for me
Kirk: heres what i do.
Cant believe this is stickied at the top of the page.
Feel free to contribute something about limb design beav. There are others here that have posted about using software programs that simulate different designs, but haven't shown any examples yet. I'd be curious to hear what that program shows on the above drawings I've provided.
This isn't about me, or my bows. This is about helping others by sharing my experience and showing results first hand. If you don't appreciate my efforts, or disagree with what I have to offer. Please feel free to offer your own experience.
As to your question Jay, with the 52" length you are not going to get those 33" draw lengths, but 30" can be accomplished. I posted photos of an early prototype 52" one pc bow showing a similar limb design, but if you look at the bow up against the straight edge, you'll notice how I angled the flat spot in the limb to the belly side using a steeper limb pad angle.
The above bow length I just posted was 60".
Quote from: Kirkll on June 03, 2026, 11:01:04 AMQuote from: dbeaver on June 03, 2026, 07:46:19 AMHeres an example of what this thread looks like,
Watsoinjay: tell me how to do this!
Kirk: heres what i do.
watsonjay: will that work for me
Kirk: heres what i do.
Cant believe this is stickied at the top of the page.
Feel free to contribute something about limb design beav. There are others here that have posted about using software programs that simulate different designs, but haven't shown any examples. I'd be curious to hear what that program shows on the above drawings I've provided.
This isn't about me, or my bows. This is about helping others by sharing my experience and showing results first hand. If you don't appreciate my efforts, or disagree with what I have to offer. Please feel free to offer your own experience.
As to your question Jay, with the 52" length you are not going to get those 33" draw lengths, but 30" can be accomplished. I posted photos of an early prototype 52" one pc bow showing a similar limb design, but if you look at the bow up against the straight edge, you'll notice how I angled the flat spot in the limb to the belly side using a steeper limb pad angle.
The above bow length I just posted was 60".
As I indicated in my previous post I really appreciate you sharing.
I am going to try to make a shim to put at the wedge of my current form to get some bend in the wedge. I'll still stick with parallels and skip the tip wedge for a lighter tip. I may add some stabilcore that I have and never used to the backside in case I need to really narrow the limb and what change it makes between that and my current limbs. Ill post my results
I'm sorry I'm not going to be of more help on the shorty bows. I never did build those 52" hybrid long bows in a 3 piece configuration. I did lengthen the fades on the design and corrected the short fade flaw, and I called it "The Yeti". But the shorty bows were not big sellers, so I drifted away from building them, and no longer offer them.
I did finally build a few shorty TD recurves called the " Yeti RC" , but those too were not in demand. Only a few avid turkey hunters ordered them, then it died off.
I can send you photos of these if you like.
Kirkl Sent you a PM to reduce our back and forths, but I guess this is another one. Anyone else make any short fast bows
Quote from: Watsonjay on June 03, 2026, 11:42:16 AMKirkl Sent you a PM to reduce our back and forths, but I guess this is another one. Anyone else make any short fast bows
Ron LaClair's Shrew, and Super Shrew were sweet shooting bows. I designed my shorty with a photo of his on my bench using carpenter cad. In case you are wondering what the hell carpenter cad is, its a hand full of finish nails, a piece of plywood, and thin fiberglass lams that bend easily.
The old Core tough material Bingham's Projects used to sell works well and bends in nice smooth transitions. The stable core we use now days is too thin to use that way. its only .015 . the old Core tough was a .023 glass weave.
Another older bow that was way ahead of its time in performance was the Sovern Balistic. John Fazio was the bowyer. Those were an RC design but well worth studying the geometry. Those babies were fast! and very stable too.
Ya. The template kennym sent me was a lot like the shrew. Now great plains makes one like it too called hodini. I shot my friends custom bodnik version of it too. It shoots good but only hit 145fps like kennyms version. I tried finding pics of that ballistik but couldn't. It looks like sovereign archery is just a archery store now??
Here is another cool shorty bow By Cascade. But the radius transition/ shape from riser to the limbs is tough to fit nicely. You'll notice the limb design has a bit of a flat section in the working portion. Or almost flat anyway... These were pretty good shooting shorty's
https://rmsgear.com/collections/bows/products/cascade-golden-hawk-magnum-46-28-1232b?_pos=1&_fid=4dabcf0e7&_ss=c
The older Damin Howitt bows had great geometry/ limb shape, but never were really fast. But using that limb shape and kicking the fades out with a power lam, or using long lean wedges on a TD version, and adding a tip wedge, it can really be a nice higher performance design.
I used to know an old timer that was really into replication of that design, but never could get the speed he wanted using par lams.
https://rmsgear.com/collections/bows/products/damon-howatt-super-diablo-60-28-60-esd-2265?_pos=2&_fid=92e73b788&_ss=c