Combining Bow Types/Styles?

[mmattockx]

Very possibly a dumb question, but what would happen if one was to combine different types/styles of bows? Say like taking a pyramid bow and then bending some deflex/reflex into it? Would you keep the circular tiller and efficient use of all the near handle wood and gain some early string tension or would the various design features end up interfering with one another?


Thanks for humouring me on this,
Mark

[PatM]

Bow styles all kind of flow together.

[Pat B]

I've seen a good shooting bow with one longbow limb and one recurve limb.

[willie]

Mark,
It would seem to me that if the the recurved area was bent into a circular tiller from reflexed, then that area of the limb would be strained more than the inner limbs,  and would respond similar to a straight limbed  bow that was  whip tillered.

If the recurve were to straighten out (or be less circular in the reflexed area, by keeping the outers a bit thicker), then one might also want to leave a bit extra thickness near the fades also, and tiller the inners "into" the fades, as the recurves will now be acting as more of a lever

http://www.primitivearcher.com/smf/index.php/topic,66666.0.html

http://www.primitivearcher.com/smf/index.php/topic,67447.msg947763.html#msg947763

[Stick Bender]

Most D/R bows that I have seen or made have been pyramidal front view at least from lower mids to tips but end up being elliptical tillered not sure you would want a circular tiller in your example by adding the D/R profile your changing the limb dynamics ,I think in your example if you skipped the deflex & added some mild reflex you could maybe get away with more of a circular tiller really only one way to find out by making one !

[Ricardovanleeuwen]

Somewhere on the forum i have Read that someone shoots a mollegabet/paddle hybrid. In my inexperienced eyes It is possible, the same way as with cross breeding animals. Bad gemetics can occur Just as the good ones. But with bows u have It in the hand.

Like the mollegabet paddle for example, i Read that the paddle bows have less chance to get set, are short.
Mollegabet shoots fast. So i guess that if It turns outs good that you end up with a fast shooting shortbow wich wont take much set.

This is Just what i think so dont blame me if im wrong

[mmattockx]

It would seem to me that if the the recurved area was bent into a circular tiller from reflexed, then that area of the limb would be strained more than the inner limbs,  and would respond similar to a straight limbed  bow that was  whip tillered.

Hmmm, that sounds correct. I think in my mind when I said 'keep the circular tiller' I was thinking of how much the limb would flex from its starting position (equivalent to the same amount of movement from flat to circular) and not getting to a true circular shape in the end. The way you put it definitely makes sense if one pulled a reflexed limb into a final circular arc.

If the recurve were to straighten out (or be less circular in the reflexed area, by keeping the outers a bit thicker), then one might also want to leave a bit extra thickness near the fades also, and tiller the inners "into" the fades, as the recurves will now be acting as more of a lever

This is what I was asking about when I said the features would interfere with one another. By the time you make the outer limbs stiffer and then add thickness near the fades you end up with a different profile than a pyramid bow. This all makes perfect sense with it being laid out as you have and explains why bows tend to look as they do.

http://www.primitivearcher.com/smf/index.php/topic,66666.0.html

What a great thread, I am going to read through that a couple times at least to try and get it all straight.

really only one way to find out by making one !

That seems to be the way it goes and may be what happens once I have a few more under my belt to be able to wing it some with an odd profile set up.


Mark

[willie]

By the time you make the outer limbs stiffer and then add thickness near the fades you end up with a different profile than a pyramid bow.

a different thickness profile?  I think you could tiller any back shape to any curve if you were not set on having a linear thickness taper.

a few years back there was a general consensus in the forum,  that a particular limb bend (elliptical or circular) was dictated by the back profile.  this must have presumed a straight taper.

there is much to be recommended for the pyramid back profile when low tip mass is desired. 

[mmattockx]

a different thickness profile?  I think you could tiller any back shape to any curve if you were not set on having a linear thickness taper.

No, I was thinking that you would change the back profile to be more efficient in use of the wood when you combined those things. I agree you could mess with the thickness to make any back profile achieve any tiller shape you wanted.

there is much to be recommended for the pyramid back profile when low tip mass is desired.

I hope so. The pyramid bow I am working on sure has been easy to get this far and seems to be an easy design to work on. I put it on the tree just to check the bend before I backed it and it only seems to need a bit of scraping on one limb to have it all bending nicely.


Mark

[willie]

I was thinking that you would change the back profile to be more efficient in use of the wood when you combined those things

Different proven designs seem to store energy in different parts of the limb, so that is part of the equasion, but the dynamics of how stored energy is delivered to the arrow on the powerstroke could be more important. There is a definition of efficiency in archery discussions that consider a "virtual Mass" model.
At the end of this thread, there is some references to the concept.   http://www.primitivearcher.com/smf/index.php/topic,63436.0.html

and at the end of this one also, http://www.primitivearcher.com/smf/index.php/topic,62879.0.html