old designs reloaded: asymmetrical bow- designs
Redhorse, I guess you?ve read my post in the PALEOPLANET:
I think I?ve answered your question about the tillering of asymmetrical bows: tiller should be the same ratio like the limbs.
Energy storage of asymmetrical bow is really high, about 10% higher than in a symmetrical designs, but speed is comparatively low. There seems to be a problem in the transfer of the energy. I?ll recheck this question, any ideas welcome...........
Redhorse, you are right about the PP. Sometimes I feel there like an unrequested person. I think most bowyers there are too much focused on selfbows with skinny tips. They miss so much!
Michael
I think I?ve answered your question about the tillering of asymmetrical bows: tiller should be the same ratio like the limbs.
Energy storage of asymmetrical bow is really high, about 10% higher than in a symmetrical designs, but speed is comparatively low. There seems to be a problem in the transfer of the energy. I?ll recheck this question, any ideas welcome...........
Redhorse, you are right about the PP. Sometimes I feel there like an unrequested person. I think most bowyers there are too much focused on selfbows with skinny tips. They miss so much!
Michael
That is what I did feel with my only asymmetrical bow, it was slower then symmetrical made same way. There might be some way to tiller it so it gets higher efficiency.
I am quite surprised to read what you say about speed. Speaking as an archer and not a bowyer, having compared two bows of same weight (Grozer Hungarian/Hun) the asymmetrical Hun was a faster bow. Aesthetically, the limbs seemed to be working in a 'nicer' way. One limb always appears more stressed in symmetrical bows due to hand/arrow placement, this can be seen in old longbows especially that have taken a fair amount of set. The upper limb always takes on a different, more defined angle. To a non bowyer it would seem that a shorter lower limb would lend itself to better, more even limb action, is this not the case?
Maybe the speed- question is a problem of my little experience with this design. I?m working for more speed.
The last asymmetrical selfbow I?ve done, stores more than 100% of energy, but it seems only to be able to transfer about 70% of it.
As once a native told me: when dreams come true, the real problems will beginning.
But fact is, since I?m using the great infos about the Golden Ratio, I got from James Harrod and Michael Winkler, as a benchmark for the tiller, efficiency is increasing.
I got another important info from a Japanese who knows how Yumi- bows are done: the lower limb is used to adjust the tiller of the much more working upper limb.
So I tiller the shorter limb at first, when it bends to a certain amount, I tiller the upper limb. Than I tiller the lower limb again for to get the desired drawweight and the tiller-ratio.
This is hard to do, when you don?t know any benchmark for this job, so my first asymmetrical bows turned out to be low- weighted.
Another experience seems to be that asymmetrical bows don?t develop any set and they seemed to be very durable and stable.
Michael
The last asymmetrical selfbow I?ve done, stores more than 100% of energy, but it seems only to be able to transfer about 70% of it.
As once a native told me: when dreams come true, the real problems will beginning.
But fact is, since I?m using the great infos about the Golden Ratio, I got from James Harrod and Michael Winkler, as a benchmark for the tiller, efficiency is increasing.
I got another important info from a Japanese who knows how Yumi- bows are done: the lower limb is used to adjust the tiller of the much more working upper limb.
So I tiller the shorter limb at first, when it bends to a certain amount, I tiller the upper limb. Than I tiller the lower limb again for to get the desired drawweight and the tiller-ratio.
This is hard to do, when you don?t know any benchmark for this job, so my first asymmetrical bows turned out to be low- weighted.
Another experience seems to be that asymmetrical bows don?t develop any set and they seemed to be very durable and stable.
Michael
This is all very interesting. Perhaps you will see the benefits of the higher energy storage once bow weight rises to a certain point? Maybe the benefits will be realized in the same way they are with a horn/sinew bow.
I believe it is at about 50-60 pounds that you start seeing the benefits of horn sinew. Below that there is too much mass per energy stored?
There are many guys among the masses at Paleoplanet that are interested in this sort of thing and probably much more of them there who actually make bows. Sometimes people are reluctant to experiment when something is working just fine. Especially when it means sacrificing perfect material to experiment with.
I believe it is at about 50-60 pounds that you start seeing the benefits of horn sinew. Below that there is too much mass per energy stored?
There are many guys among the masses at Paleoplanet that are interested in this sort of thing and probably much more of them there who actually make bows. Sometimes people are reluctant to experiment when something is working just fine. Especially when it means sacrificing perfect material to experiment with.
Thanks Patrick for clearing something up with the Paleoplanet.
Anyway the skinny tip thing is great!
You?re right about the higher drawweight.
Today I?ve rechecked the energy storage of my last asymmetrical bow, it is really 110%, I?ve shot it with heavier arrows(350grains) equipped with smaller feathers and lighter points. The bow shots these arrows with 145f/s, 26", 31.8lbs, thats a very good speed, but efficiency is still about 50%. This is disappointing but this is my challenge to awake as much as possible of its pot.energy.
Michael
Anyway the skinny tip thing is great!
You?re right about the higher drawweight.
Today I?ve rechecked the energy storage of my last asymmetrical bow, it is really 110%, I?ve shot it with heavier arrows(350grains) equipped with smaller feathers and lighter points. The bow shots these arrows with 145f/s, 26", 31.8lbs, thats a very good speed, but efficiency is still about 50%. This is disappointing but this is my challenge to awake as much as possible of its pot.energy.
Michael
With higher weight it should be better, you may have tips for a much stronger bow and that eats efficiency.