This is probably the last for this topic. This discovery about the effective lever really changes my entire understanding of siyah. Proving the 48° and 66° is really unexpected. Good that everything comes together so that I can move to another topic lol.
@@BenRothArchery probably arrow spine and gpp. I had always wanted to do that because many ignorant archers are using severely underweighted arrows, which damages our bows. It gives us headache in warranty.
This and the last are excellent. I think you are dead right with sine and cosine vector components. The work on 60° being important is very revealing. Thankyou for your work
Thanks, that's very useful. I think you're friends is right in regards to the material losing it's ability to withstand stress before it fails completely. However I believe the reason why we might not notice this in a bow is because the bow limb is exposed to tension on the back and compression on the belly, when on of the sides starts to weaken only slightly the other sides stress level increases dramatically and the bow limb breaks more rapidly, because the bow is not one piece of homogeneous material. I hope it makes sense.
Yes, that's what I think as well. Even though technically there's a yield point, but it happens so quickly within a blink of an eye. So we don't usually experience it. The moment 1 thing fail, it triggers a chain reaction that produces the catastrophic failure within a fraction of a second. We are left stunned not understanding what just happened.
Hy, cool video. I'm running tests with a similar topic. One thing you might consider for your next video is the ratio betwen the limb and the stiff leaver. There has to be a sweetspot with a surtain ratio betwen limb and leaver. Based on the laws oft leverage. ;-)
There really isn't. It depends on the poundage of the bow and intended gpp. Low poundage couldn't overcome the heavy siyah, so lower leverage is better. With higher poundage, higher leverage is better. There's also a limitation based on the material strain limit. The top flight record (probably carbon limb) has a leverage to limb of only about 0.5. Top flight for hornbow has leverage probably around 3
Bows are made from polymer bonds. The yield is true more for materials like metal, where there are metallic bonds and the structure is crystalline as compared to a polymer polymer bond. After exceeding the max yilding force the metal crystals would start to deform. But in pulymers like wood, sinue etc. Its like strands of molecules which when break, dont attach to nearby molecules like atoms of metals would. So i think thats why it snaps immediately.
i experienced an incident broken bow. My oponion, it depends on material. If syntethic material it will suddenly failure. If natural material it will yielding and rupture.
Really impressive work. Had to re-watch certain parts to get the point. Have you made any FD curves and mapped out the 48, 60 and 66 degree points to see any correlation?
Don't think there's a correlation. FD curve is more related to the geometry of the bow. But it only turns out that at 66°, it's very difficult to fight the stacking even with an excellent bow geometry. So it's far more likely to notice the stack at that particular angle.
The 48° is actually rather difficult to observe. It feels like the portion directly after the big bump in the FD curve of a recurve, but before becoming linear. Somewhere in there, but difficult to trace without precision tool/setup.
@@bambooarchery I'm making a new spreadsheet to compare bows and diagnose why one bow outperforms another. I have 60 degree string angle as a data point. I think measuring 60 degree before and after the string has lifted of the string bridge is worth it (also measuring to the kasan-eye). But I thought it might be worth adding 48 or 66 degree as well. I will remeasure my bows and see if I find anything correlating
@@robinj6997 this has been studied before. As the siyah angle increase from 0° to 60° (relative to limb), energy storage increase, but cast efficiency decrease. The reverse is true. At one point, between 30-35° is where the cast efficiency and energy storage yield the highest level of output (highest speed).
Imo, math and physics doesn't lie. Material can affect perception through hysterisis, creating an illusion of smoothness. There's 2 bows that are full natural bow in this test. But the FDC doesn't care about perception. Ivar spoke highly about only geometry matters, and therefore my calculations focus on how geometry affects the math and forces. Try test it with all the various bows you have. The way I did it was to signal to the cameraman to take a photo when I feel the resistance. Then use the photo to measure the angle using a protractor. Repeat it to get an average value.
This is an awesome video series, and a great channel! Keep up the great work! I'd be very curious about learning more about string bridges and if you would be able to make a bow with non-string contact siyahs like a Magyar/Changshao/ general "Hunnic" design an improved design by adding string bridges (and potentially lengthening the string to maintain the same brace height and therefore power stroke).
@@Couponuser16 adding string bridge will increase brace height, reducing powerstroke. If you increase the string length to drop the brace height such that the brace height is the same as without the string bridge, then the limb has to bend less than before and could potentially become unstable, depending on how tall the bridge to be compensated.
@@bambooarchery Thank you for your thoughts! I gotta couple more Qs for you if you are up for it. What would be the concern with having the bending limb do less bending than before, would it put an increased amount of force at the siyah / limb junction point? And If stability was maintained how much do you think potential energy & cast speed would be impacted by a string bridge large enough to make a non-string contact bow into a bow with string contact during the draw if any?
@@bambooarchery I do have the force draw curve on the bow I have in mind, not sure how would be the best to share if you are interested. It isn't linear, but it also isn't as extreme early on as other designs with more aggressive siyah angles. It's also an "XL" version, being 64" from nock to nock to accommodate a 34" draw from the belly so the F/D curve is more elongated than other Magyar/Xiongnu/Hunnic designs. But since the siyah angle is so much less aggressive than other designs, and the bow is extra long I think I might have a chance to sacrifice some stability. It is also admittedly a bit overbuilt due to these customizations. It's also an authentic horn composite, if that impacts things. But it is 47lbs @ 28" (from the belly), starts stacking after 33" where it is 59lbs, and goes up to 64lbs in that last inch with a 7.5" brace height (bow string is 59"). 25% of max draw at 11" (16lbs), 50% of max draw at 20" (32lbs), 75% at 28.5" (48 lbs), 92% at 33" (59lbs), and then 64lbs at 34".
Interesting: I had one asian bow in my collection. It was some Short Kaya Korean bow (I forgot model) I know my technique is decent drawing like english longbow (but with thumb instead of fingers). The kaya bow shot fast but it made my back muscles very tight, with knots and sore because of stacking (uncomfortable to me). I ended up giving the kaya away. I never have that muscle tightness sensation with my long bow (same draw weight, but smoother draw). Do archery muscles respond differently to stacking?
There's 2 part of the story: 1) just because 2 bows are the same poundage at 28", doesn't mean they are the same poundage at 30". For example a stacky bow may be 40# 28", but gain 4# per inch (10% per inch, 10ppi), and reaches 48# 30". But a Super Recurve of 40# 28", only gained 0.8# per inch (2% per inch, 2ppi), and reaches 41.6# 30". Obviously 48# will stress your muscles out more than 41.6#. 2) since a stacky bow gain higher percentage of poundage per inch, it also means it'll drain you more just to maintain that drawlength because you aren't really holding the exact drawlength like a machine. Your muscles try to pull, then collapse, pull and collapse, repeatedly, it's a pumping action. Repeatedly subjected to this micro movement, you burn a lot of stamina to fight the stacking. A smoother bow drains you less.
@@bambooarchery Speaking of string angles, kramar ammons some western archer, made a video stating shorter string angles from limb shoot faster because they have less distance from limb tip and retrack faster to brace. Is that right???
@@JonWickkk-cn1iv no, that's completely false. Shorter string and limbs simply have less mass, so shorter bows can reach higher dryfire speed. This is only useful under the context of flight archery, where you use the lightest possible arrow to get max speed. But for normal use, the opposite is true. If the arrows are reasonably heavy, such as 10gpp commonly used, then longer bows and longer string can actually be more efficient. Firstly because longer bows are smoother which increases energy storage. Secondly, if optimized in weight, then a longer limb and string can actually move more distance for same amount of limb/string travel and time, this literally means greater speed. As proof, the AF Babylon 59" is about 10fps faster than AF Tatar 49".
@@bambooarchery there is one detail you did not fully expound on in the three part series (you did vaguely) On western bows, the recurve is rested on a circle curve and I think some of them are static tip even if they look bending. For asian bows, I just realized, the recurve is at a straight line you can measure with a protractor after looking at many of them. Lets say you have two bows and all other factors are equal and they recurve the same amount. The only difference is one bow is recurved on a curve (western style) and one is not. How would the draw force curve be different?
@@JonWickkk-cn1iv when something is short, it is less bendy. So even on a working recurve, the last few inches don't bend. Just observe where that last bending spot is and treat the length after as a rigid siyah. All other rules apply
I was not expecting another one. You're like a mad scientist 😁
Awesome work!
This is probably the last for this topic. This discovery about the effective lever really changes my entire understanding of siyah. Proving the 48° and 66° is really unexpected. Good that everything comes together so that I can move to another topic lol.
@@bambooarchery What will your next topic be? Eagerly awaiting :)
@@BenRothArchery probably arrow spine and gpp. I had always wanted to do that because many ignorant archers are using severely underweighted arrows, which damages our bows. It gives us headache in warranty.
@@bambooarchery That is good to hear!! I didn’t know about arrow weights until it was almost too late. Looking forward to it. 😊
This and the last are excellent. I think you are dead right with sine and cosine vector components. The work on 60° being important is very revealing. Thankyou for your work
It's very self satisfying when the pieces all come together nicely. 😊
Great chanel, very interesting content ! Thanks a lot for sharing these reflections and knowledge !
Thanks, that's very useful. I think you're friends is right in regards to the material losing it's ability to withstand stress before it fails completely. However I believe the reason why we might not notice this in a bow is because the bow limb is exposed to tension on the back and compression on the belly, when on of the sides starts to weaken only slightly the other sides stress level increases dramatically and the bow limb breaks more rapidly, because the bow is not one piece of homogeneous material. I hope it makes sense.
Yes, that's what I think as well. Even though technically there's a yield point, but it happens so quickly within a blink of an eye. So we don't usually experience it. The moment 1 thing fail, it triggers a chain reaction that produces the catastrophic failure within a fraction of a second. We are left stunned not understanding what just happened.
i believe 4.0 is on the way, great explaination.
Nah, I think I covered everything. Move on to another topic
Hy,
cool video. I'm running tests with a similar topic. One thing you might consider for your next video is the ratio betwen the limb and the stiff leaver. There has to be a sweetspot with a surtain ratio betwen limb and leaver. Based on the laws oft leverage.
;-)
There really isn't. It depends on the poundage of the bow and intended gpp. Low poundage couldn't overcome the heavy siyah, so lower leverage is better. With higher poundage, higher leverage is better. There's also a limitation based on the material strain limit. The top flight record (probably carbon limb) has a leverage to limb of only about 0.5. Top flight for hornbow has leverage probably around 3
Bows are made from polymer bonds. The yield is true more for materials like metal, where there are metallic bonds and the structure is crystalline as compared to a polymer polymer bond.
After exceeding the max yilding force the metal crystals would start to deform. But in pulymers like wood, sinue etc. Its like strands of molecules which when break, dont attach to nearby molecules like atoms of metals would. So i think thats why it snaps immediately.
i experienced an incident broken bow. My oponion, it depends on material. If syntethic material it will suddenly failure. If natural material it will yielding and rupture.
nice presentation
Really impressive work. Had to re-watch certain parts to get the point. Have you made any FD curves and mapped out the 48, 60 and 66 degree points to see any correlation?
Don't think there's a correlation. FD curve is more related to the geometry of the bow. But it only turns out that at 66°, it's very difficult to fight the stacking even with an excellent bow geometry. So it's far more likely to notice the stack at that particular angle.
The 48° is actually rather difficult to observe. It feels like the portion directly after the big bump in the FD curve of a recurve, but before becoming linear. Somewhere in there, but difficult to trace without precision tool/setup.
@@bambooarchery I'm making a new spreadsheet to compare bows and diagnose why one bow outperforms another. I have 60 degree string angle as a data point. I think measuring 60 degree before and after the string has lifted of the string bridge is worth it (also measuring to the kasan-eye). But I thought it might be worth adding 48 or 66 degree as well.
I will remeasure my bows and see if I find anything correlating
@@robinj6997 this has been studied before. As the siyah angle increase from 0° to 60° (relative to limb), energy storage increase, but cast efficiency decrease. The reverse is true. At one point, between 30-35° is where the cast efficiency and energy storage yield the highest level of output (highest speed).
You tested laminated bows only I guess and Ivar relates to composite bows with horn and sinew. could make a difference, but what do I know :)
Imo, math and physics doesn't lie. Material can affect perception through hysterisis, creating an illusion of smoothness. There's 2 bows that are full natural bow in this test. But the FDC doesn't care about perception. Ivar spoke highly about only geometry matters, and therefore my calculations focus on how geometry affects the math and forces.
Try test it with all the various bows you have. The way I did it was to signal to the cameraman to take a photo when I feel the resistance. Then use the photo to measure the angle using a protractor. Repeat it to get an average value.
This is an awesome video series, and a great channel! Keep up the great work! I'd be very curious about learning more about string bridges and if you would be able to make a bow with non-string contact siyahs like a Magyar/Changshao/ general "Hunnic" design an improved design by adding string bridges (and potentially lengthening the string to maintain the same brace height and therefore power stroke).
@@Couponuser16 adding string bridge will increase brace height, reducing powerstroke. If you increase the string length to drop the brace height such that the brace height is the same as without the string bridge, then the limb has to bend less than before and could potentially become unstable, depending on how tall the bridge to be compensated.
@@bambooarchery Thank you for your thoughts! I gotta couple more Qs for you if you are up for it. What would be the concern with having the bending limb do less bending than before, would it put an increased amount of force at the siyah / limb junction point? And If stability was maintained how much do you think potential energy & cast speed would be impacted by a string bridge large enough to make a non-string contact bow into a bow with string contact during the draw if any?
@@Couponuser16 hard to predict. You have to look at the force draw curve
@@bambooarchery I do have the force draw curve on the bow I have in mind, not sure how would be the best to share if you are interested. It isn't linear, but it also isn't as extreme early on as other designs with more aggressive siyah angles. It's also an "XL" version, being 64" from nock to nock to accommodate a 34" draw from the belly so the F/D curve is more elongated than other Magyar/Xiongnu/Hunnic designs. But since the siyah angle is so much less aggressive than other designs, and the bow is extra long I think I might have a chance to sacrifice some stability. It is also admittedly a bit overbuilt due to these customizations. It's also an authentic horn composite, if that impacts things.
But it is 47lbs @ 28" (from the belly), starts stacking after 33" where it is 59lbs, and goes up to 64lbs in that last inch with a 7.5" brace height (bow string is 59").
25% of max draw at 11" (16lbs), 50% of max draw at 20" (32lbs), 75% at 28.5" (48 lbs), 92% at 33" (59lbs), and then 64lbs at 34".
@@Couponuser16 you can send to my WhatsApp or Facebook, both before and after the change for comparison
have you read the traditional bowyers bible? if you havent, i think it would be a very good book for you.
Interesting: I had one asian bow in my collection. It was some Short Kaya Korean bow (I forgot model) I know my technique is decent drawing like english longbow (but with thumb instead of fingers). The kaya bow shot fast but it made my back muscles very tight, with knots and sore because of stacking (uncomfortable to me). I ended up giving the kaya away. I never have that muscle tightness sensation with my long bow (same draw weight, but smoother draw). Do archery muscles respond differently to stacking?
There's 2 part of the story:
1) just because 2 bows are the same poundage at 28", doesn't mean they are the same poundage at 30". For example a stacky bow may be 40# 28", but gain 4# per inch (10% per inch, 10ppi), and reaches 48# 30". But a Super Recurve of 40# 28", only gained 0.8# per inch (2% per inch, 2ppi), and reaches 41.6# 30". Obviously 48# will stress your muscles out more than 41.6#.
2) since a stacky bow gain higher percentage of poundage per inch, it also means it'll drain you more just to maintain that drawlength because you aren't really holding the exact drawlength like a machine. Your muscles try to pull, then collapse, pull and collapse, repeatedly, it's a pumping action. Repeatedly subjected to this micro movement, you burn a lot of stamina to fight the stacking. A smoother bow drains you less.
@@bambooarchery Speaking of string angles, kramar ammons some western archer, made a video stating shorter string angles from limb shoot faster because they have less distance from limb tip and retrack faster to brace. Is that right???
@@JonWickkk-cn1iv no, that's completely false. Shorter string and limbs simply have less mass, so shorter bows can reach higher dryfire speed. This is only useful under the context of flight archery, where you use the lightest possible arrow to get max speed.
But for normal use, the opposite is true. If the arrows are reasonably heavy, such as 10gpp commonly used, then longer bows and longer string can actually be more efficient. Firstly because longer bows are smoother which increases energy storage. Secondly, if optimized in weight, then a longer limb and string can actually move more distance for same amount of limb/string travel and time, this literally means greater speed. As proof, the AF Babylon 59" is about 10fps faster than AF Tatar 49".
@@bambooarchery there is one detail you did not fully expound on in the three part series (you did vaguely) On western bows, the recurve is rested on a circle curve and I think some of them are static tip even if they look bending. For asian bows, I just realized, the recurve is at a straight line you can measure with a protractor after looking at many of them. Lets say you have two bows and all other factors are equal and they recurve the same amount. The only difference is one bow is recurved on a curve (western style) and one is not. How would the draw force curve be different?
@@JonWickkk-cn1iv when something is short, it is less bendy. So even on a working recurve, the last few inches don't bend. Just observe where that last bending spot is and treat the length after as a rigid siyah. All other rules apply
seems the failures you have experienced are not material failure but joint failures.
Asian guy is an ignorant.
👍🏼👍🏼👍🏼 you are a scholar!!! 👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼👍🏼❤️
Great series!
i've tried this to find the limb length for 60 degree string angle and end up with a quadratic equation, law of cosine etc..🥲