Main Discussion Area > English Warbow
Arrow Pass/Handle location
alanesq:
It will still bend along it's length, but wont the loads on the limbs be out of balance ?
Isn't the point of an arrow pass mark to dictate where you hold the bow ?
Davepim:
Yes Alan you are correct, the arrow pass dictates where you hold the bow, but the lower limb of a warbow is in any case supposed to be slightly stiffer than the upper, and so accomodates this slight difference in load on the limbs. I find it very difficult to explain exactly what I mean here, so apologies if I am causing confusion :D I can only say, by way of excuse, that even using dead centre of the bow as the arrow pass seems to work, only that it probably isn't optimal; I just go with what the real experts tell me :)
Dave
alanesq:
I understand what you mean, and I agree with you
a bow can be made to be drawn from any point (e.g. the Japanese bows)
I have heard it said that the limbs on a warbow should not be equal but I am not sure if this is the case or if it just comes from people not realising that the handle area should not be located at the centre if the bow is to be supported from its centre (i.e. they see the handle is not perfectly central so assume the limbs are different lengths)?
I wonder where the arrow pass was located on the Mary Rose bows ?
bow-toxo:
--- Quote from: alanesq on May 05, 2010, 07:10:47 am ---
I understand what you mean, and I agree with you
a bow can be made to be drawn from any point (e.g. the Japanese bows)
I have heard it said that the limbs on a warbow should not be equal but I am not sure if this is the case or if it just comes from people not realising that the handle area should not be located at the centre if the bow is to be supported from its centre (i.e. they see the handle is not perfectly central so assume the limbs are different lengths)?
I wonder where the arrow pass was located on the Mary Rose bows ?
--- End quote ---
As mentioned in a nother post;Since we are making longbows of the late mediaeval period, it might make sense to use the method used at the time. Balance the arc tillered bow on the thumb, then close the hand on the bow. No need to mark anything. You might glue a leather strip at the arrow pass like one of the Mary Rose bows.
Erik
DCM4:
It's awefully complicated, to be so simple. ;-)
The best answer I can come up with is, (the arbitrary 2") above center orientation is an artifact of the engineering influences in the early 20th century (Hickman, Nagler, Klopsteg), promoted and made possible by the use of modern materials which immediately followed.
Wrt to the physics, one must consider the role of string angle. For a demonatration, fold your fave bow string in half, then note the location of center in relation to your nock point. Positive tiller's purpose is to offset this inherent asymetry, of drawing the arrow, necessarily, above the fulcum of the bow hand, also most frequently above dimensional center of the bow.
What I've determined is you can "time" a bow regardless, within reason, of the relative lenghts of the two limbs. I personally value having the arrow pass closer to center, because I can find no justification for handicapping the upper limb by making it both shorter, and necessarily weaker, which puts it doubly at a disadvantage to the lower. When building with natural materials, where we tread as close it's elastic threshold as possible (even beyond in most cases), I prefer to not give the lower limb a "free ride."
It's a really, really good question and study of it will reveal many fundamental, and most frequently not appretiated, aspects of the bowyer's craft. That said, I think most bowyers still use trial and error to time their bows, regardless of the predetermined design and geometry.
With a full arc, so called "bendy handle" bow, one really must shoot it according to it's design, that is placing the bow hand fulcrum at the stiffest point along it's lenght regardless of where that point falls. Or risk getting beaten to death by the resulting handshock. And even on stiff handled bows, one risks pulling a limb out of tiller if you shoot it much different than it was designed.
I look at it as a triangle, arrow pass, positive tiller and nock point. The higher the arrow pass, the more tiller required. The more tiller, the higher the nock point. Since there's a lower limit to nock point (below which one risks interference between the arrow and knuckle/arrow rest), the bowyer's task is to put in just enough tiller so nock point can be used to adjust this back out, or in, according to the style (high wrist versus heeling, three under or split) of the archer. Heeling/split calling for more tiller, and high wrist/three under opposite.
But I'd love to hear my ideas challenged. It's far from resolved in my own thinking, although I've dedicated a great deal of thought, research and experimentation to the subject.
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