Light weight horn bows
Traditional hornbow designs will not result fast bow with low poundage.
It is quite cleat that is bow is 3cm wide and 120# it would have to be scaled 1cm wide for 40# to keep the efficiency, and that would be bending sideways, thus not possible.
Decreasing more from thinkness and less is any from width will leads well functional bow that mostly look and functions like original, but with decreased efficiency.
... ok old news ...
What could done to make hornbows of low weight and higher efficiency?
"Simple" modifications of the design:
1. longer ears and shorter bending part
* Lower poundage bow does not need as long bending part,
since the part is thinner and thus bends better.
2. Ears made with lighter wood
* It is not possible to make ear thinner, so lighter wood would decrese
mass
3. Longer handle and shorter bending part
* ??
4. More wood in the core and much thinner horn and somewhat thinner sinew.
* Horn is heavies part. It bends more than wood, but is less stif than wood. When poundage is less there is less need for that, so thicker core with thinner horn would be optimal. Same with sinew but with less extent.
It is not possible to add more reflex since existent designs are allready reflexed to the max. Moreover adding reflex would not remarkably help
with efficiency as the energy store during stringing will not leave the bow, but the energy added comes from early draw weight.
Complete modification of design:
Make the changes from bending to non bending gradual. Use the heaviest material on less moving parts nearer the grip and the lighter makerials near the string.
So the idea would be that the bow would be made form:
1. Horn
2. Sinew
3. Core wood such as mapple
4. ear wood such as spruce of pine.
The part near handle would be sinew-core wood - horn.
The horn as the heavies material would phase out first. Then would
phaze out the sinew. After that would the core wood phaze out.
The whole would be tillered so that the parts with lighter material would
bend less than the parts with heavier materials.
The idea would be to do the same to horn bows that Tim Baker pecan bow did for wooden bow.
--
Ideas and critisism of what I wrote above.
It is quite cleat that is bow is 3cm wide and 120# it would have to be scaled 1cm wide for 40# to keep the efficiency, and that would be bending sideways, thus not possible.
Decreasing more from thinkness and less is any from width will leads well functional bow that mostly look and functions like original, but with decreased efficiency.
... ok old news ...
What could done to make hornbows of low weight and higher efficiency?
"Simple" modifications of the design:
1. longer ears and shorter bending part
* Lower poundage bow does not need as long bending part,
since the part is thinner and thus bends better.
2. Ears made with lighter wood
* It is not possible to make ear thinner, so lighter wood would decrese
mass
3. Longer handle and shorter bending part
* ??
4. More wood in the core and much thinner horn and somewhat thinner sinew.
* Horn is heavies part. It bends more than wood, but is less stif than wood. When poundage is less there is less need for that, so thicker core with thinner horn would be optimal. Same with sinew but with less extent.
It is not possible to add more reflex since existent designs are allready reflexed to the max. Moreover adding reflex would not remarkably help
with efficiency as the energy store during stringing will not leave the bow, but the energy added comes from early draw weight.
Complete modification of design:
Make the changes from bending to non bending gradual. Use the heaviest material on less moving parts nearer the grip and the lighter makerials near the string.
So the idea would be that the bow would be made form:
1. Horn
2. Sinew
3. Core wood such as mapple
4. ear wood such as spruce of pine.
The part near handle would be sinew-core wood - horn.
The horn as the heavies material would phase out first. Then would
phaze out the sinew. After that would the core wood phaze out.
The whole would be tillered so that the parts with lighter material would
bend less than the parts with heavier materials.
The idea would be to do the same to horn bows that Tim Baker pecan bow did for wooden bow.
--
Ideas and critisism of what I wrote above.
Here is a picture how would the matrial change in a limb.
I do not mean straight limb design... or one with constant thickness.
It has been draw straight do minimize the effort to draw it...
I do not mean straight limb design... or one with constant thickness.
It has been draw straight do minimize the effort to draw it...
jkekoni, just make it like an original, but reduce thickness of horn, core and sinew- backing.
I?ve done some different types of horn- bows for research, just to get some impressions about their physical and mechanical behaviour.
Drawweights are from 40- 50 lbs.
It works, anyway efficiency suffers and you ask yourself, all this work, a selfbow with the same drawweight is much more worth the effort.
Michael
I?ve done some different types of horn- bows for research, just to get some impressions about their physical and mechanical behaviour.
Drawweights are from 40- 50 lbs.
It works, anyway efficiency suffers and you ask yourself, all this work, a selfbow with the same drawweight is much more worth the effort.
Michael
All variation of your phantasie is for you better , jkekoni , than seriouz study our ancestors - who work in this problem thousands years ? I like phantasy , its mi work - i am artists , but ... Can you see closer to korean hornbow ? This little 122cm bow vith his 40-50 lb shoot very wel in 150 and more metres.
I would have thought shorter tips would also be a good idea.